Добірка наукової літератури з теми "CMOS 65 nm, 45 nm et 32 nm"

Abstract Idelalisib (Zydelig™), a first-in-class, selective, oral inhibitor of PI3Kδ, is approved for the treatment of chronic lymphocytic leukemia (CLL) in combination with rituximab and as monotherapy for patients with follicular lymphoma who have received at least 2 prior therapies. Despite remarkable clinical efficacy, complete responses are rare, highlighting the need to identify more effective therapies, including combinations of novel agents. GS-4059 (ONO-4059) is an investigational next generation BTK inhibitor with improved selectivity compared to ibrutinib. We report here on the results of the combination of idelalisib and GS-4059 in lymphoma cell lines. Methods: Growth inhibition was assessed using CellTiter-Glo™ Assay (Promega) after 72-96 h incubation with idelalisib and GS-4059. Synergy for anti-proliferative effects was assessed using the Bliss Model of Independence (Meletiadis et al., Med Mycol, 2005), using MacSynergy II (Prichard et al., MacSynergyTM II, Version 1.0, 1993) or the Chalice software (Horizon Discovery, Inc., Lehar et al., Nature Biotech, 2009). Lysates were analyzed by Simple Western (Protein Simple) or Western blot. Ibrutinib resistance was established by continuous passaging of a clonal isolate of TMD8 in the presence of 10-20 nM ibrutinib. Resistance mutations were identified by whole exon sequencing (WES, GeneWiz). Results: GS-4059 potently inhibited growth (EC50<26 nM) of 3 ABC-DLBCL cell lines (OCI-LY10, Ri-1, and TMD8) that were also sensitive to idelalisib (EC50<210 nM). The combination showed synergistic growth inhibition in OCI-LY10 and TMD8 and increased apoptosis above the level observed with single agents (Table 1). Idelalisib and GS-4059 synergistically inhibited growth in 2 MCL cell lines (Rec-1 and JMV-2). The combination was additive in the other lymphoma cell lines sensitive to these agents. Two mechanisms of resistance to BTK inhibitors were identified in TMD8: an inactivating mutation in the NF-kB inhibitor A20 (TNFAIP3 Q143*), and a BTK mutation (C481F). TMD8 cells with the BTK (C481F) mutation only were less sensitive to idelalisib (Emax = 14% at 1 uM vs. 86% in parental, Figure 1A). Addition of GS-4059 did not enhance growth inhibition in those clones. A20 mutant only TMD8 cells were resistant to GS-4059 (EC50>10 μM), but were sensitive to idelalisib, albeit less than parental (EC50 ≥ 4300 nM vs. 54 nM). Addition of 50 nM GS-4059 to idelalisib provided further growth inhibition, consistent with the presence of wild-type BTK, and increased the potency of idelalisib to a level comparable to parental TMD8 (EC50 ≥ 99 nM, n=5 clones, Figure 1B). Conclusion: Idelalisib and GS-4059 synergistically inhibited the growth of a subset of DLBCL and MCL cell lines. A20 mutation and loss-of -function was identified as a novel mechanism of resistance to BTK inhibitors. Idelalisib less potently inhibited the growth of A20 mutant TMD8 but the combination with GS-4059 provided additional benefit. TMD8 with a BTK-C481F mutation, were resistant to idelalisib and to the combination with GS-4059. These data suggest that the combination of idelalisib and GS-4059 may overcome some mechanisms of resistance to BTK. Table 1. Synergistic inhibition of ABC-DLBCL cell viability by GS-4059 and idelalisib GS-4059 (nM) EC50 of idelalisib (nM) when combined with GS-4059 TMD-8 OCI-LY-10 Ri-1 Pfeiffer 0 254 440 442 174 5 130 38 372 NTc 15 32 22 372 NT 45 24 5 372 174 EC50 shift (fold) 10.6 88 12 1 Synergy Score 65 65 0 0 Figure 1. Growth inhibition of ibrutinib resistant TMD8 with (A) BTK C481F mutation or (B) A20 Q143* mutation A. B. Figure 1. Growth inhibition of ibrutinib resistant TMD8 with (A) BTK C481F mutation or (B) A20 Q143* mutation. / A. / B. Figure 2. Figure 2. Disclosures Tannheimer: Gilead Sciences: Employment, Other: Share holder. Sorensen:Gilead Sciences: Employment, Other: Share holder. Yahiaoui:Gilead Sciences: Employment, Other: Share holder. Meadows:Gilead Sciences: Employment, Other: Share holder. Li:Gilead Sciences: Employment, Other: Share holder. Yue:Gilead Sciences: Employment, Other: Share holder. Tumas:Gilead Sciences: Employment, Equity Ownership. Queva:Gilead Sciences: Other: Share holder.

In recent years, Ge-based group-IV alloys (GeSn, SiGeSn) have received a significant amount of attention as candidates to replace Silicon for future low power and high performance nanoelectronics [1]. The interest in these materials stems primarily from the fact that, by varying the Sn-content of the alloy, it is possible to precisely tune its bandgap from indirect to direct [2], which even opens up the possibility to switch the carrier transport from larger mass low mobility L-valley electrons to the lower mass and high mobility Γ-valley electrons. Adding Si atoms into GeSn alloys enables additional strain engineering by decoupling the lattice constant from the band gap and enables the fabrication of devices to target specific applications. Ge exhibits superior hole mobility over Si and GeSn is predicted to further improve carrier mobilities for both electrons and holes, while still retaining Si CMOS compatibility [3]. In this Abstract, we present the fabrication and characterization of Ge- and GeSn-based vertical gate-all-around (GAA) nanowire (NW) p-MOSFETs. Multilayer stacks of Ge and GeSn were grown on a Ge virtual substrate (Ge-VS) using industrial CVD reactors and subsequently characterized, confirming the high quality of the alloys. On these GeSn/Ge heterostructures, vertical GAA nanowire FETs were fabricated using a top-down approach. First, nanowires were defined by electron-beam lithography and subsequently etched anisotropically using reactive ion etching (RIE). The diameter of the nanowires was reduced by digital etching, consisting of repeated combined GeOx layer formation by plasma oxidation and removal in diluted HF solution. This way nanowires with a diameter down to 20 nm and a height of 210 nm were fabricated. A two-step process was employed for gate dielectric formation to ensure a low interface trap density: (i), deposition of a thin layer of Al2O3, followed by an O2-plasma post-oxidation step; (ii) deposition of a HfO2 dielectric layer to reach the required EOT (equivalent oxide thickness). TiN deposited by sputtering forms the gate metal. Planarization and isotropic dry etching were performed to remove the TiN on the top of the nanowire. After a second planarization step, NiGe-contacts were formed on the exposed top nanowire by Ni-deposition followed by a forming-gas annealing step. Finally, metal contacts for gate and source/drain were added. The resulting Ge-NW-pMOSFETs exhibit high electrical performances. A low subthreshold slope (SS) of 66 mV/dec, a low drain-induced barrier lowering (DIBL) of 35 mV/V and an I on/I off-ratio of 2.1×106 were measured for nanowires with a diameter of 20 nm. For 65 nm NWs, the I on/I off-ratio improves, which is attributed to the decreased contact resistance on top of the NWs, leading to larger on-currents. The peak transconductance for the Ge NWs reached ~190 µS/µm (V DS=-0.5 V). Adopting a GeSn/Ge-heterostructure, with GeSn on top of the nanowire used as source the device performances are strongly enhanced. The on-current I on was increased by ~32%, mostly due to the reduced contact resistivity of the smaller bandgap of GeSn compared to Ge. It was also observed that adopting GeSn alloys leads to an increase in transconductance, G max, to a respectable value of ~870 µS/µm, almost 3 times larger as reported to date for Ge NWs. Moreover, both SS and DIBL are improved by decreasing the NW diameter as a consequence of improved electrostatic gate control over the channel. These results demonstrate that the incorporation of GeSn into Ge-MOSFET technology yields a significant advantage and confirm its high potential for low-power-high-performance nanoelectronics. Fig. 1: (a) Schematic of the GAA nanowire FET based on a GeSn/Ge-heterostructure. (b) Optical image on the metallic contacts (c) Transfer curve of a Ge nanowire pFET with a diameter of 20 nm. The SS is 68 mV/dec and the DIBL is 35 mV/V. (d) Transfer curves of Ge0.92Sn0.08/Ge nanowire pFETs with a diameter of 65 nm and different EOTs. Acknowledgments The authors acknowledge support from the German BMBF project “SiGeSn NanoFETs”. References: [1] M. Liu et al. ACS Appl. Nano Mater. 4, 94-101 (2021) [2] S. Wirths et al. Nature Photonics 9, 88-92 (2015) [3] J. Kouvetakis, J. Menendez, A. V. G. Chizmeshya: Annu. Rev. Mater. Res. 36:497-554 (2006) Figure 1

EDITORIAL 4 A Dozen Years, A Dozen Roses Lapeña JF ORIGINAL ARTICLES 6 Efficacy of Clarithromycin Versus Methylprednisolone in the Treatment of Non-Eosinophilic and Eosinophilic Nasal Polyposis: A Randomized Controlled Trial Gammad JC, Chua AH, Templonuevo-Flores CS 14 Simulation Platform for Myringotomy with Ventilation Tube Insertion in Adult Ears Chan AL, Carrillo RJD, Ong KC 21 Prevalence of Supraorbital Ethmoid Air Cells among Filipinos Carlos ALC, Gelera JE 24 Recurrent Laryngeal Nerve Paralysis and Hypocalcemia in Superior to Inferior Compared to Inferior to Superior Dissection Approaches in Thyroidectomy Yu RD 28 Pathologic Laryngoscopic Findings, Number of Years in Teaching, and Related Factors among Secondary Public-School Teachers in Bacolod City, Negros Occidental Mundo NP, Vinco VV 32 Tracheal Diameter Estimates Using Age-Related Formula Versus Radiographic Findings: Which Approximates the Actual Tracheostomy Tube in Pediatric Patients? De Guzman ICS CASE REPORTS 37 Lethal Midline Granuloma in a 15-Year-Old Girl: A Diagnostic Dilemma Gonzales ICA 41 Tuberculosis of the Temporomandibular Region Santos JM, Reala ET 45 Crab Shell Impaction in the Larynx with Aphonia Parekh NM, Kashyap PR SURGICAL INNOVATION AND INSTRUMENTATION 48 PHONETOVOX: A Novel Device for Alaryngeal Speech Econ ME, Soriano RG 53 Can Modified Laryngosternopexy (Laryngoclaviculopexy) Project the Larynx Anteriorly? Carrillo RJC, Lapeña JF FEATURED GRAND ROUNDS 56 Cleft Beyond the Lip and Palate: A Bilateral Tessier Cleft Canta LAB FROM THE VIEWBOX 60 Pulsatile Tinnitus Due to a Sigmoid Sinus Diverticulum and/or Dehiscence Yang NW UNDER THE MICROSCOPE 62 Respiratory Epithelial Adenomatoid Hamartoma Carnate JM, Abelardo AD PASSAGES 64 Armando T. Chiong, Sr. (1930 - 2018) Jamir JC 65 Carlos P. Dumlao (1950 - 2018) Pontejos AQY

Hamsters were exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days. Equal amounts of proteins from urinary bladder or liver extracts of control and arsenic-treated hamsters were labeled with Cy3 and Cy5 dyes, respectively. After differential in gel electrophoresis and analysis by the DeCyder software, several protein spots were found to be down-regulated and several were up regulated. Our experiments indicated that in the bladder tissues of hamsters exposed to arsenite, transgelin was down-regulated and GST-pi was up-regulated. The loss of transgelin expression has been reported to be an important early event in tumor progression and a diagnostic marker for cancer development [29-32]. Down-regulation of transgelin expression may be associated with the carcinogenicity of inorganic arsenic in the urinary bladder. In the liver of arsenite-treated hamsters, ornithine aminotransferase was up-regulated, and senescence marker protein 30 and fatty acid binding protein were down-regulated. The volume ratio changes of these proteins in the bladder and liver of hamsters exposed to arsenite were significantly different than that of control hamsters. Introduction Chronic exposure to inorganic arsenic can cause cancer of the skin, lungs, urinary bladder, kidneys, and liver [1-6]. The molecular mechanisms of the carcinogenicity and toxicity of inorganic arsenic are not well understood [7-9). Humans chronically exposed to inorganic arsenic excrete MMA(V), DMA(V) and the more toxic +3 oxidation state arsenic biotransformants MMA(III) and DMA (III) in their urine [10, 11], which are carcinogen [12]· After injection of mice with sodium arsenate, the highest concentrations of the very toxic MMA(III) and DMA(III) were in the kidneys and urinary bladder tissue, respectively, as shown by experiments of Chowdhury et al [13]. Many mechanisms of arsenic toxicity and carcinogenicity have been suggested [1, 7, 14] including chromosome abnormalities [15], oxidative stress [16, 17], altered growth factors [18], cell proliferation [19], altered DNA repair [20], altered DNA methylation patterns [21], inhibition of several key enzymes [22], gene amplification [23] etc. Some of these mechanisms result in alterations in protein expression. Methods for analyzing multiple proteins have advanced greatly in the last several years. In particularly, mass spectrometry (MS) and tandem MS (MS/MS) are used to analyze peptides following protein isolation using two-dimensional (2-D) gel electrophoresis and proteolytic digestion [24]. In the present study, Differential In Gel Electrophoresis (DIGE) coupled with Mass Spectrometry (MS) has been used to study some of the proteomic changes in the urinary bladder and liver of hamsters exposed to sodium arsenite in their drinking water. Our results indicated that transgelin was down-regulated and GST-pi was up-regulated in the bladder tissues. In the liver tissues ornithine aminotransferase was up-regulated, and senescence marker protein 30, and fatty acid binding protein were down-regulated. Materials and Methods Chemicals Tris, Urea, IPG strips, IPG buffer, CHAPS, Dry Strip Cover Fluid, Bind Silane, lodoacetamide, Cy3 and Cy5 were from GE Healthcare (formally known as Amersham Biosciences, Uppsala, Sweden). Thiourea, glycerol, SDS, DTT, and APS were from Sigma-Aldrich (St. Louis, MO, USA). Glycine was from USB (Cleveland, OH, USA). Acrylamide Bis 40% was from Bio-Rad (Hercules, CA, USA). All other chemicals and biochemicals used were of analytical grade. All solutions were made with Milli-Q water. Animals Male hamsters (Golden Syrian), 4 weeks of age, were purchased from Harlan Sprague Dawley, USA. Upon arrival, hamsters were acclimated in the University of Arizona animal care facility for at least 1 week and maintained in an environmentally controlled animal facility operating on a 12-h dark/12-h light cycle and at 22-24°C. They were provided with Teklad (Indianapolis, IN) 4% Mouse/Rat Diet # 7001 and water, ad libitum, throughout the acclimation and experimentation periods. Sample preparation and labelling Hamsters were exposed to sodium arsenite (173 mg) in drinking water for 6 days and the control hamsters were given tap water. On the 6th day hamsters were decapitated rapidly by guillotine. Urinary bladder tissues and liver were removed, blotted on tissue papers (Kimtech Science, Precision Wipes), and weighed. Hamster urinary bladder or liver tissues were homogenized in lysis buffer (30mMTris, 2M thiourea, 7M urea, and 4% w/w CHAPS adjusted to pH 8.5 with dilute HCI), at 4°C using a glass homogenizer and a Teflon coated steel pestle; transferred to a 5 ml acid-washed polypropylene tube, placed on ice and sonicated 3 times for 15 seconds. The sonicate was centrifuged at 12,000 rpm for 10 minutes at 4°C. Small aliquots of the supernatants were stored at -80°C until use (generally within one week). Protein concentration was determined by the method of Bradford [25] using bovine serum albumin as a standard. Fifty micrograms of lysate protein was labeled with 400 pmol of Cy3 Dye (for control homogenate sample) and Cy5 Dye (for arsenic-treated urinary bladder or liver homogenate sample). The samples containing proteins and dyes were incubated for 30 min on ice in the dark. To stop the labeling reaction, 1uL of 10 mM lysine was added followed by incubation for 10 min on ice in the dark. To each of the appropriate dye-labeled protein samples, an additional 200 ug of urinary bladderor liver unlabeled protein from control hamster sample or arsenic-treated hamster sample was added to the appropriate sample. Differentially labeled samples were combined into a single Microfuge tube (total protein 500 ug); protein was mixed with an equal volume of 2x sample buffer [2M thiourea, 7M urea, pH 3-10 pharmalyte for isoelectric focusing 2% (v/v), DTT 2% (w/v), CHAPS 4% (w/v)]; and was incubated on ice in the dark for 10 min. The combined samples containing 500 ug of total protein were mixed with rehydration buffer [CHAPS 4% (w/v), 8M urea, 13mM DTT, IPG buffer (3-10) 1% (v/v) and trace amount of bromophenol blue]. The 450 ul sample containing rehydration buffer was slowly pipetted into the slot of the ImmobilinedryStripReswelling Tray and any large bubbles were removed. The IPG strip (linear pH 3-10, 24 cm) was placed (gel side down) into the slot, covered with drystrip cover fluid (Fig. 1), and the lid of the Reswelling Tray was closed. The ImmobillineDryStrip was allowed to rehydrate at room temperature for 24 hours. First dimension Isoelectric focusing (IEF) The labeled sample was loaded using the cup loading method on universal strip holder. IEF was then carried out on EttanIPGphor II using multistep protocol (6 hr @ 500 V, 6 hr @ 1000 V, 8 hr @ 8000 V). The focused IPG strip was equilibrated in two steps (reduction and alkylation) by equilibrating the strip for 10 min first in 10 ml of 50mM Tris (pH 8.8), 6M urea, 30% (v/v) glycerol, 2% (w/v) SDS, and 0.5% (w/v) DTT, followed by another 10 min in 10 ml of 50mM Tris (pH 8.8), 6M urea, 30% (v/v) glycerol, 2% (w/v) SDS, and 4.5% (w/v) iodoacetamide to prepare it for the second dimension electrophoresis. Second dimension SDS-PAGE The equilibrated IPG strip was used for protein separation by 2D-gel electrophoresis (DIGE). The strip was sealed at the top of the acrylamide gel for the second dimension (vertical) (12.5% polyacrylamide gel, 20x25 cm x 1.5 mm) with 0.5% (w/v) agarose in SDS running buffer [25 mMTris, 192 mM Glycine, and 0.1% (w/v) SDS]. Electrophoresis was performed in an Ettan DALT six electrophoresis unit (Amersham Biosciences) at 1.5 watts per gel, until the tracking dye reached the anodic end of the gel. Image analysis and post-staining The gel then was imaged directly between glass plates on the Typhoon 9410 variable mode imager (Sunnyvale, CA, USA) using optimal excitation/emission wavelength for each DIGE fluor: Cy3 (532/580 nm) and Cy5 (633/670 nm). The DIGE images were previewed and checked with Image Quant software (GE Healthcare) where all the two separate gel images could be viewed as a single gel image. DeCyde v.5.02 was used to analyze the DIGE images as described in the Ettan DIGE User Manual (GE Healthcare). The appropriate up-/down regulated spots were filtered based on an average volume ratio of ± over 1.2 fold. After image acquisition, the gel was fixed overnight in a solution containing 40% ethanol and 10% acetic acid. The fixed gel was stained with SyproRuby (BioRad) according to the manufacturer protocol (Bio-Rad Labs., 2000 Alfred Nobel Drive, Hercules, CA 94547). Identification of proteins by MS Protein spot picking and digestion Sypro Ruby stained gels were imaged using an Investigator ProPic and HT Analyzer software, both from Genomic Solutions (Ann Arbor, MI). Protein spots of interest that matched those imaged using the DIGE Cy3/Cy5 labels were picked robotically, digested using trypsin as described previously [24] and saved for mass spectrometry identification. Liquid chromatography (LC)- MS/MS analysis LC-MS/MS analyses were carried out using a 3D quadrupole ion trap massspectrometer (ThermoFinnigan LCQ DECA XP PLUS; ThermoFinnigan, San Jose, CA) equipped with a Michrom Paradigm MS4 HPLC (MichromBiosources, Auburn, CA) and a nanospray source, or with a linear quadrupole ion trap mass spectrometer (ThermoFinnigan LTQ), also equipped with a Michrom MS4 HPLC and a nanospray source. Peptides were eluted from a 15 cm pulled tip capillary column (100 um I.D. x 360 um O.D.; 3-5 um tip opening) packed with 7 cm Vydac C18 (Vydac, Hesperia, CA) material (5 µm, 300 Å pore size), using a gradient of 0-65% solvent B (98% methanol/2% water/0.5% formic acid/0.01% triflouroacetic acid) over a 60 min period at a flow rate of 350 nL/min. The ESI positive mode spray voltage was set at 1.6 kV, and the capillary temperature was set at 200°C. Dependent data scanning was performed by the Xcalibur v 1.3 software on the LCQ DECA XP+ or v 1.4 on the LTQ [27], with a default charge of 2, an isolation width of 1.5 amu, an activation amplitude of 35%, activation time of 50 msec, and a minimal signal of 10,000 ion counts (100 ion counts on the LTQ). Global dependent data settings were as follows: reject mass width of 1.5 amu, dynamic exclusion enabled, exclusion mass width of 1.5 amu, repeat count of 1, repeat duration of a min, and exclusion duration of 5 min. Scan event series were included one full scan with mass range of 350-2000 Da, followed by 3 dependent MS/MS scans of the most intense ion. Database searching Tandem MS spectra of peptides were analyzed with Turbo SEQUEST, version 3.1 (ThermoFinnigan), a program that allows the correlation of experimental tandem MS data with theoretical spectra generated from known protein sequences. All spectra were searched against the latest version of the non redundant protein database from the National Center for Biotechnology Information (NCBI 2006; at that time, the database contained 3,783,042 entries). Statistical analysis The means and standard error were calculated. The Student's t-test was used to analyze the significance of the difference between the control and arsenite exposed hamsters. P values less than 0.05 were considered significant. The reproducibility was confirmed in separate experiments. Results Analysis of proteins expression After DIGE (Fig. 1), the gel was scanned by a Typhoon Scanner and the relative amount of protein from sample 1 (treated hamster) as compared to sample 2 (control hamster) was determined (Figs. 2, 3). A green spot indicates that the amount of protein from sodium arsenite-treated hamster sample was less than that of the control sample. A red spot indicates that the amount of protein from the sodium arsenite-treated hamster sample was greater than that of the control sample. A yellow spot indicates sodium arsenite-treated hamster and control hamster each had the same amount of that protein. Several protein spots were up-regulated (red) or down-regulated (green) in the urinary bladder samples of hamsters exposed to sodium arsenite (173 mg As/L) for 6 days as compared with the urinary bladder of controls (Fig. 2). In the case of liver, several protein spots were also over-expressed (red) or under-expressed (green) for hamsters exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days (Fig. 3). The urinary bladder samples were collected from the first and second experiments in which hamsters were exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days and the controls were given tap water. The urinary bladder samples from the 1st and 2nd experiments were run 5 times in DIGE gels on different days. The protein expression is shown in Figure 2 and Table 1. The liver samples from the 1st and 2nd experiments were also run 3 times in DIGE gels on different days. The proteins expression were shown in Figure 3 and Table 2. The volume ratio changed of the protein spots in the urinary bladder and liver of hamsters exposed to arsenite were significantly differences than that of the control hamsters (Table 1 and 2). Protein spots identified by LC-MS/MS Bladder The spots of interest were removed from the gel, digested, and their identities were determined by LC-MS/MS (Fig. 2 and Table 1). The spots 1, 2, & 3 from the gel were analyzed and were repeated for the confirmation of the results (experiments; 173 mg As/L). The proteins for the spots 1, 2, and 3 were identified as transgelin, transgelin, and glutathione S-transferase Pi, respectively (Fig. 2). Liver We also identified some of the proteins in the liver samples of hamsters exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days (Fig. 3). The spots 4, 5, & 6 from the gels were analyzed and were repeated for the confirmation of the results. The proteins for the spots 4, 5, and 6 were identified as ornithine aminotransferase, senescence marker protein 30, and fatty acid binding protein, respectively (Fig. 3) Discussion The identification and functional assignment of proteins is helpful for understanding the molecular events involved in disease. Weexposed hamsters to sodium arsenite in drinking water. Controls were given tap water. DIGE coupled with LC-MS/MS was then used to study the proteomic change in arsenite-exposed hamsters. After electrophoresis DeCyder software indicated that several protein spots were down-regulated (green) and several were up-regulated (red). Our overall results as to changes and functions of the proteins we have studied are summarized in Table 3. Bladder In the case of the urinary bladder tissue of hamsters exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days, transgelin was down-regulated and GST-pi was up-regulated. This is the first evidence that transgelin is down-regulated in the bladders of animals exposed to sodium arsenite. Transgelin, which is identical to SM22 or WS3-10, is an actin cross linking/gelling protein found in fibroblasts and smooth muscle [28, 29]. It has been suggested that the loss of transgelin expression may be an important early event in tumor progression and a diagnostic marker for cancer development [30-33]. It may function as a tumor suppressor via inhibition of ARA54 (co-regulator of androgen receptor)-enhanced AR (androgen receptor) function. Loss of transgelin and its suppressor function in prostate cancer might contribute to the progression of prostate cancer [30]. Down-regulation of transgelin occurs in the urinary bladders of rats having bladder outlet obstruction [32]. Ras-dependent and Ras-independent mechanisms can cause the down regulation of transgelin in human breast and colon carcinoma cell lines and patient-derived tumorsamples [33]. Transgelin plays a role in contractility, possibly by affecting the actin content of filaments [34]. In our experiments loss of transgelin expression may be associated or preliminary to bladder cancer due to arsenic exposure. Arsenite is a carcinogen [1]. In our experiments, LC-MS/MS analysis showed that two spots (1 and 2) represent transgelin (Fig. 2 and Table 1). In human colonic neoplasms there is a loss of transgelin expression and the appearance of transgelin isoforms (31). GST-pi protein was up-regulated in the bladders of the hamsters exposed to sodium arsenite. GSTs are a large family of multifunctional enzymes involved in the phase II detoxification of foreign compounds [35]. The most abundant GSTS are the classes alpha, mu, and pi classes [36]. They participate in protection against oxidative stress [37]. GST-omega has arsenic reductase activity [38]. Over-expression of GST-pi has been found in colon cancer tissues [39]. Strong expression of GST-pi also has been found in gastric cancer [40], malignant melanoma [41], lung cancer [42], breast cancer [43] and a range of other human tumors [44]. GST-pi has been up-regulated in transitional cell carcinoma of human urinary bladder [45]. Up-regulation of glutathione – related genes and enzyme activities has been found in cultured human cells by sub lethal concentration of inorganic arsenic [46]. There is evidence that arsenic induces DNA damage via the production of ROS (reactive oxygen species) [47]. GST-pi may be over-expressed in the urinary bladder to protect cells against arsenic-induced oxidative stress. Liver In the livers of hamsters exposed to sodium arsenite, ornithine amino transferase was over-expressed, senescence marker protein 30 was under-expressed, and fatty acid binding protein was under-expressed. Ornithine amino transferase has been found in the mitochondria of many different mammalian tissues, especially liver, kidney, and small intestine [48]. Ornithine amino transferase knockdown inhuman cervical carcinoma and osteosarcoma cells by RNA interference blocks cell division and causes cell death [49]. It has been suggested that ornithine amino transferase has a role in regulating mitotic cell division and it is required for proper spindle assembly in human cancer cells [49]. Senescence marker protein-30 (SMP30) is a unique enzyme that hydrolyzes diisopropylphosphorofluoridate. SMP30, which is expressed mostly in the liver, protects cells against various injuries by stimulating membrane calcium-pump activity [50]. SMP30 acts to protect cells from apoptosis [51]. In addition it protects the liver from toxic agents [52]. The livers of SMP30 knockout mice accumulate phosphatidylethanolamine, cardiolipin, phosphatidyl-choline, phosphatidylserine, and sphingomyelin [53]. Liver fatty acid binding protein (L-FABP) also was down- regulated. Decreased liver fatty acid-binding capacity and altered liver lipid distribution hasbeen reported in mice lacking the L-FABP gene [54]. High levels of saturated, branched-chain fatty acids are deleterious to cells and animals, resulting in lipid accumulation and cytotoxicity. The expression of fatty acid binding proteins (including L-FABP) protected cells against branched-chain saturated fatty acid toxicity [55]. Limitations: we preferred to study the pronounced spots seen in DIGE gels. Other spots were visible but not as pronounced. Because of limited funds, we did not identify these others protein spots. In conclusion, urinary bladders of hamsters exposed to sodium arsenite had a decrease in the expression of transgelin and an increase in the expression of GST-pi protein. Under-expression of transgelin has been found in various cancer systems and may be associated with arsenic carcinogenicity [30-33). Inorganic arsenic exposure has resulted in bladder cancer as has been reported in the past [1]. Over-expression of GST-pi may protect cells against oxidative stress caused by arsenite. In the liver OAT was up regulated and SMP-30 and FABP were down regulated. These proteomic results may be of help to investigators studying arsenic carcinogenicity. The Superfund Basic Research Program NIEHS Grant Number ES 04940 from the National Institute of Environmental Health Sciences supported this work. Additional support for the mass spectrometry analyses was provided by grants from NIWHS ES06694, NCI CA023074 and the BIOS Institute of the University of Arizona. Acknowledgement The Author wants to dedicate this paper to the memory of his former supervisor Dr. H. VaskenAposhian who passed away in September 6, 2019. He was an emeritus professor of the Department of Molecular and Cellular Biology at the University of Arizona. 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Introduction Methods Resuts Discussion Conclusions Acknowledgments Authors' contributions Competing interests Ethical approval References Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study Inaam N. Ali1, Muthana M. Awad2, Alaa S. Mahmood2,* 1 Water and Environment Directorate, Ministry of Sciences and Technology, Baghdad, Iraq 2 Department of Biology, College of Science, University of Anbar, Anbar, Iraq * Corresponding author: A. S. Mahmood (alaashm91@gmail.com) Abstract: Objective: To assess the effect of methotrexate and omega-3 combination on cytogenetic changes of bone marrow and activities of some enzymatic antioxidants. Methods: Fifty-six mature male Wistar rats were divided into two experimental groups and a control group. The first experimental group was sub-divided into three sub-groups depending on the concentration of methotrexate (MTX): X1 (0.05 mg/kg MTX), X2 (0.125 mg/kg MTX) and X3 (0.250 mg/kg MTX), which were given intraperitoneally on a weekly basis for eight weeks. The second experimental group (MTX and omega-3 group) was also sub-divided into three sub-groups (Y1, Y2 and Y3), which were injected intraperitoneally with 0.05, 0.125 and 0.25 mg/kg MTX, respectively, weekly for eight weeks accompanied by the oral administration of 300 mg/kg omega-3. The rats of the control group were given distilled water. The enzymatic activity of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) were measured in the sera of rats. In addition, the mitotic index (MI) and chromosomal aberrations of bone marrow were also studied. Results: MTX resulted in a significant decrease in the activities of CAT, SOD and GR compared to the controls. It also increased the MI and chromosomal aberrations of rat bone marrows. On the other hand, omega-3 significantly increased the activities of the investigated enzymatic antioxidants and reduced the MI and chromosomal aberrations in treated mice when given in combination with MTX. Conclusions: MTX has a genotoxic effect on the bone marrow by increasing the MI and all types of chromosomal aberrations and decreasing the enzymatic activity of CAT, SOD and GR. The addition of omega-3 can lead to a protective effect by reducing the toxic and mutagenic effects of MTX. Keywords: Methotrexate, Omega-3, Antioxidant, Wistar rat, Chromosomal aberration, Mitotic index 1. Introduction Methotrexate (MTX) is a folic acid antagonist because of their chemical similarity [1]. Vezmar et al. [2] showed that MTX affects the synthesis of nucleic acids deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) by interfering with the biosynthesis of thymine and purines. It also directly affects the rapidly dividing and intact cells, especially those in the mucous membranes of the mouth, intestine and bone marrow [3]. Omega-3 is a type of unsaturated fats, which are classified as essential fatty acids that cannot be manufactured by the body and should be taken with food [4]. Sources of omega-3 include fish oils, such as salmon, sardines and tuna, as well as soybeans, walnuts, raisins and linseed, almonds and olive oils [5]. Omega-3 is used in the prevention of a number of diseases such as rheumatoid arthritis, ulcerative colitis, asthma, atherosclerosis, cancer, and cardiovascular diseases [6]. A large amount of evidence indicates that omega-3 fatty acids have significant health benefits, including anti-inflammatory and antioxidant properties besides their effect on blood cholesterol levels [7]. Antioxidants retard the oxidation process by different mechanisms such as the removal of free radicals [8]. Enzymatic antioxidants include catalase (CAT), which is the first line of defense in the cell that removes hydrogen peroxide formed during biological processes by converting it into an aldehyde, and superoxide dismutase (SOD). There are three major families of SOD enzymes: manganese SOD (Mn-SOD) in the mitochondria and peroxisomes, iron SOD (Fe-SOD) in prokaryote cells and copper/zinc SOD (Cu-Zn SOD) in the cytoplasm of eukaryote cells [9]. Therefore, changes in the metal co-factors (manganese, iron, copper and zinc) can alter the effectiveness of SOD and may lead to diseases as a result of oxidative stress [10]. Glutathione reductase (GR) is also an enzymatic antioxidant that converts the oxidized glutathione to the reduced glutathione in the presence of NADPH, which is oxidized to NADP [11]. Therefore, the aim of the present study was to assess the effects of MTX and omega-3 on the cytogenetic changes of bone marrow as well as the activities of CAT, SOD and GR enzymatic antioxidants in male rats. 2. Method 2.1. Laboratory animals and experimental design Fifty-six mature male Wistar rats (Rattus norvegicus), aged 10–12 weeks old and weighing 250–300 gm, were used in the present study. The rats were kept in separate cages, with natural 13- hour light and 11-hour dark periods in a contamination-free environment with a controlled temperature (28.0 ± 1.0°C). In addition, rats were maintained on a standard diet and tap water ad libitum. The rats were randomly allocated to two experimental groups and a control group. The first experimental group (MTX group) included 24 rats injected intraperitoneally with different MTX dilutions with distilled water [12]. It was sub-divided into three sub-groups (eight rats per sub-group) according to MTX concentration as follows: X1 (0.05 mg/kg MTX), X2 (0.125mg/kg MTX) and X3 (0.25 mg/kg MTX). All rats were given a single dose of the specified MTX concentration weekly for eight weeks. The second experimental group (MTX and omega-3 group) included 24 rats allocated to three sub-groups (Y1, Y2 and Y3), which were injected intraperitoneally with 0.05, 0.125 and 0.25 mg/kg MTX, respectively, weekly for eight weeks accompanied by the oral administration of 300 mg/kg omega-3. The control group included eight rats that were intraperitoneally injected with distilled water and given a single dose of distilled water orally weekly for eight weeks. 2.2. Blood collection and processing After the end of the dosing period, 5 ml of blood were withdrawn from the heart (by cardiac puncture) using a 5 cc disposable syringe. The collected blood was immediately poured into a clean sterile screw-capped tube (plain tube) and left for coagulation in a water bath at 37°C for 15 minutes. After coagulation of blood, the plain tube was centrifuged for 5 minutes at 1500 rpm. Then the samples were stored at -20°C for subsequent analysis. 2.3. Measurement of the activity of antioxidant enzymes The antioxidant activities of CAT, SOD and GR were measured using enzyme-linked immunosorbent assay kits purchased from Kamiya Biomedical Company (Seattle, WA, US), according to the manufacturer's instructions. 2.4. Cytogenetic study of bone marrow Rats were killed by cervical dislocation, and their hip bones were cleaned from surrounding muscles and then dissected by cutting both ends of the bone. Five milliliters of physiological buffered saline were injected inside the bone to withdraw bone marrow into a test tube. Tubes were centrifuged at 2000 rpm/10 minutes. The supernatant was then removed, and 10 ml of KCL solution (0.075 M) were added to the sediment. The mixture was then incubated at 37 °C in a water bath for 30 minutes, with shaking from time to time. The tubes were then centrifuged at 2000rpm/10 minutes to remove the supernatant. However, 5 ml of a freshly prepared fixative solution (methanol: glacial acetic acid 1:3) were added gradually in the form of droplets into the inner wall of the tube with constant mixing. After that, the tubes were placed at 4 °C for half an hour to fix the cells. This process was repeated for three times, and the cells were then suspended in 2 ml of the fixative solution. The tubes were centrifuged at 2000 rpm for 5 minutes, and the supernatant was then removed while the cells were re-suspended in 1-2 ml of cold fixative solution. After shaking the tubes, 4–5 drops were then taken from each tube onto a clean slide from a height of about three feet to provide an opportunity for the cells and nuclei to spread well. The slides were stained with acridine orange solution (0.01%) for 4–5 minutes, incubated in Sorensen’s buffer (0.06M, pH 6.5) for a minute. and then examined using a fluorescence microscope Olympus BX 51 America at a wavelength of 450–500 nm [13, 14]. A total of 1000 cells were examined, and both dividing and non-dividing cells were calculated [13]. Mitotic index (MI) was calculated according to the following formula [13]: MI= No. of dividing cells / 1000 × 100 2.5. Analysis of chromosomal aberrations of bone marrow cells A total of 1000 dividing cells were examined on the stained slides under a fluorescence microscope at a wavelength of 45–500 nm. The examined cells were at the first metaphase of the mitotic division, where chromosomal aberrations are clear and can be easily seen [13]. 2.6. Statistical analysis Data were analyzed using the Statistical Analysis System (SAS®) software, version 9.1 (Cary, NC, USA) [15]. Effects were expressed as mean ± standard error (SE) and statistically compared using a completely randomized design analysis of variance and least significant differences. Differences at P values <5 were considered statistically significant. 3. Results 3.1. Effects of MTX and MTX-omega-3 combination on antioxidant enzymatic activities Table (1) shows significantly lower SOD activities among rats treated with MTX or MTX-omega-3 compared to controls. Moreover, sera of rats receiving relatively high doses of MTX (sub-groups X2 and X3) showed the lowest enzymatic activities of 4.29 ± 0.01 IU and 3.93 ± 0.11 IU, respectively. On the other hand, CAT activity differed significantly between treated and control rats as well as among treated rats themselves, In this respect, the controls showed the highest activity of 39.38 ±0.02 IU, while those receiving the highest MTX concentration, either alone or in combination with omega-3 (sub-groups X3 and Y3), showed the lowest activities of 30.97 ± 0.03 IU and 32.12± 0.06 IU, respectively. Regarding GR activity, control rats showed a higher activity of 53.09± 0.05 IU compared to treated ones; however, the differences in GR activities in rats given low doses of MTX, either alone or in combination with omega-3 (sub-groups X1 and Y1), were not statistically significant. On the other hand, rats in sub-groups X3 and Y3 showed the lowest GR activities of 34.59 ± 0.63 IU and 37.15 ±0.01, respectively, with statistically significant differences from other sub-groups. 3.2. Effects of MTX and MTX-omega-3 combination on mitotic index of bone marrow cells Figure (1) shows a significant decrease in the MI in all treated groups compared to control. In addition, there was a reverse association between MTX concentration and MI, where rats treated with the highest dose of MTX (sub-group X3) showed a significant decrease in MI compared to all other treated rat sub-groups. In addition, rats in sub-groups treated with MTX and omega-3 (sub-groups Y1, Y2 and Y3) showed a significant increase in MI compared to their counterpart rats receiving MTX only. Table 1. Activity of antioxidant enzymes in rats treated with MTX and MTX-omega-3 Group Enzymatic activity (mean± SE) SOD (IU) CAT (IU) GR (µmol) Control 6.41±0.02 a 39.38±0.02 a 53.09±0.05 a X1 (0.05 mg MTX/ kg) 5.33±0.01 b 37.81±0.01 c 51.12±0.06 a Y1 (0.05 mg MTX + 300 mg omega-3/ kg) 6.08±0.04 a 38.40±0.02 b 51.97±0.03 a X2 (0.125 mg MTX/ kg) 4.29±0.01 cd 33.13±0.01 e 42.34±0.03 b Y2 (0.125 mg MTX + 300 mg omega-3/ kg) 4.99±0.40 b 36.68±0.02 d 43.02±3.04 b X3 (0.25 mg MTX/ kg) 3.93±0.11 d 30.97±0.03 g 34.59±0.63 c Y3 (0.25 mg MTX + 300 mg omega-3/ kg) 4.47±0.02 c 32.12±0.06 f 37.15±0.01 c SE, Standard error; IU, international unit; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; *statistically significant at P < 0.05; **statistically significant at P < 0.01. Means with different letters within the same column showed a statistically significant difference. 3.3. Effects of MTX and MTX-omega-3 combination on chromosomal aberrations of bone marrow cells Rats receiving higher concentrations of MTX (sub-group X3) showed a significant increase in all types of chromosomal aberrations, i.e., chromatid gaps, chromosome gaps, chromatid breaks, chromosome breaks, deletions and simple fragments (Figure 2 and Table 2) than those of the control group or other treated sub-groups. All rats treated with MTX-omega-3 combination showed a significant decrease in almost all types of chromosomal aberrations compared to their counterpart rats receiving MTX alone (Table 2). Figure 1. Effect of MTX and MTX-omega-3 on the MI of bone marrow cells of treated rats compared to the controls. The groups X1 (0.05 MTX), X2 (0.125 MTX) and X3 (0.250 MTX) were compared to the control group, while the groups Y1 (0.05 MTX+ omega-3), Y2 (0.125 MTX+ omega-3) and Y3 (0.25 MTX+ omega-3) were compared to X1, X2 and X3, respectively. Figure 2. Effect of MTX and MTX-omega-3 on chromosomal aberration as seen under fluorescence microscope after staining with acridine orange: (1) a simple fragment; (2) a chromatid gap; (3) a chromosomal gap (A) and a chromosomal break (B). 4. Discussion The present experiment reveals that the addition of omega-3 to MTX alleviates its effects on the activities of the antioxidant enzymes CAT, SOD and GR, and decreases the MI as well as all types of chromosomal aberrations in the bone marrow cells. Daham et al. [16] showed that the decline in antioxidants associated with chemotherapy is attributed to the increase in lipid peroxidation caused by these kinds of drugs, which increase the level of free radicals. In addition, Weijl et al. [17] showed that some chemotherapeutic drugs have a negative effect on the antioxidant levels such as GR, whose activity decreases as a result of its involvement in many cellular processes such as cell defenses against the toxicity of some compounds. Al-Dalawy et al. [18] found that the decrease in the level of SOD is an evidence of its increased activity due to the increased release of free radicals. MTX causes an increase in the release of free radicals, including the OH radical that causes direct damage to DNA [16]. Al-Helaly [19] showed that the amount of food taken has an effect on antioxidants, where nutritional deficiency decreases the antioxidant levels, thus increasing free radicals that cause damage to DNA. Table 2. Chromosomal aberrations of bone marrow cells in rats treated with MTX and MTX-omega-3 Group Type of chromosomal aberration(mean ± SE) Chromatid gap Chromosome Gap Chromatid breaks Chromosome breaks Deletion Simple Fragments Chromosomal aberration (%) Control 1.33±0.33 e 0.00±0.00 e 1.67±0.33 c 0.33±0.15 c 0.00±0.00 0.67±0.33 cd 0.04±0.005 f X1 2.75±0.47 cd 1.50±0.28 cd 2.50±0.64 bc 1.00±0.41 bc 0.50±0.28 bc 0.75±0.25 bcd 0.09±0.02 de Y1 1.75±0.47 de 0.75±0.25 de 1.50±0.28 c 1.00±0.00 bc 0.75±0.25 abc 0.75±0.25 abc 0.065±0.005 ef X2 4.67±0.33 b 2.67±0.33 ab 2.67±0.33 bc 1.67±0.33 ab 0.67±0.33 abc 1.67±0.33 ab 0.14±0.006 bc Y2 3.00±0.00 c 2.00±0.00 bc 3.00±0.057 bc 1.33±0.33 b 0.67±0.33 abc 0.33±0.15 d 0.106±0.003 cd X3 6.80±0.37 a 3.00±0.31 a 4.60±0.74 a 2.40±0.24 a 1.40±0.24 a 1.80±0.37 a 0.20±0.017 a Y3 5.60±0.40 ab 2.40±0.24 ab 3.60±0.24 ab 1.80±0.20 ab 1.20±0.20 ab 1.40±0.24 abc 0.16±0.003 b LSD 1.231** 0.814** 0.602** 0.841** 0.774* 0.941** 3.499* SE, Standard error; * statistically significant at P < 0.05; ** statistically significant at P < 0.01. Means with different letters within the same column showed a statistically significant difference. X1 (0.05 mg MTX/ kg); X2 (0.125 mg MTX/ kg); X3 (0.25 mg MTX/ kg); Y1 (0.05 mg MTX + 300 mg omega-3/ kg); Y2 (0.125 mg MTX + 300 mg omega-3/ kg); Y3 (0.25 mg MTX + 300 mg omega-3/ kg). In the present study, the intraperitoneal administration of MTX to rats also caused a decrease in the MI of bone marrow and a significant increase in the rate of abnormal chromosomal aberration compared to the control rats. This finding is consistent with those reported previously [20], [21]. The effect of MTX can be attributed to its ability to interfere with the genetic material, leading to the appearance of toxic and mutagenic consequences. Rushworth et al. [22] reported that MTX leads to a lack of dihydrofolate reductase, which is the key to the growth and cell division processes. This, in turn, leads to a reduction of the nucleotides involved in the building of DNA and, therefore, to a stop or obstruction of the repair mechanisms of the damaged DNA. In addition, Wong and Choi [23] concluded that MTX inhibits the action of enzymes controlling the purine metabolism, which leads to the accumulation of adenosine in addition to the damage of the molecule itself and to the occurrence of chromosomal aberrations. Jafer et al. [24] reported the ability of MTX to induce chromosomal aberration in humans or animals by preventing the repair of DNA and affecting the proteins found in chromosomes. These findings were also confirmed by Hussain et al. [25], who found that MTX causes an increase in chromosomal aberrations. In the present study, the MI showed a significant increase in rat sub-groups treated with MTX-omega-3 combination, but there was a decrease in the rate of chromosomal aberration, which confirms the role of omega-3 unsaturated fatty acids in protecting the cell from the impact of free radicals [26], [27]. Attia and Nasr [28] reported the antioxidant effect of omega-3, which was attributed to the reduction in lipid peroxidation and the increase in SOD and CAT or the stimulation of GR. It is noteworthy that GR leads to the synthesis of reduced glutathione, which is important in the defense of the cell against toxic substances and the prevention of the occurrence of mutations [29]. 5. Conclusions MTX significantly decreases the activity of enzymatic antioxidants, reduce the MI and increase the chromosomal aberrations of all types in bone marrow. This gives further evidence on the genotoxic effects of MTX on the bone marrow. On the other hand, omega-3 shows a protective effect by reducing the toxic and mutagenic effects of MTX. Acknowledgments The authors thank the staff of the Water and Environment Directorate, Ministry of Science and Technology, Baghdad, Iraq for their cooperation. They also thank Dr. Jasim Al-Niami for his technical and scientific guidance. Authors' contributions INA, MMA and ASM contributed to the study design and analyzed data. All authors contributed to the manuscript drafting and revising and approved the final submission. Competing interests The authors declare that they have no competing interests associated with this article. Ethical approval The ethical clearance of this study was obtained from the Ethics Committee of the College of Science, University of Anbar (Reference No. A. D. 51 in 30/8/2015). References Yuen CW, Winter ME. Methotrexate (MTX). In: Basic clinical pharmacokinetics, Winter ME, editor. Philadelphia, USA: Lippincott Williams & Wilkins; 2010. p.p. 304–25. Google Scholar Vezmar S, Becker A, Bode U, Jaehde U. Biochemical and clinical aspects of methotrexate neurotoxicity. Chemotherapy 2003; 49: 92–104. DOI PubMed - Google Scholar Tian H, Cronstein BN. Understanding the mechanisms of action of methotrexate implications for the treatment of rheumatoid arthritis. Bull NYU Hosp Jt Dis 2007; 65: 168–73. PubMed - Google Scholar El-Khayat Z, Rasheed WI, Elias T, Hussein J, Oraby F, Badawi M, et al. Protective effect of either dietary or pharmaceutical n-3 fatty acids on bone loss in ovariectomized rats. Maced J Med Sci 2010; 3: 9–16. DOI - Google Scholar Kris-Etherton PM, Harris WS, Appel LJ; Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids and cardiovascular disease. Arterioscler Thromb Vasc Biol 2003; 23: e20–30. DOI - PubMed - Google Scholar Calder PC. Polyunsaturated fatty acids and inflammation. Prostaglandins Leukot Essent Fatty Acids 2006; 75: 197–202. DOI - PubMed - Google Scholar Begin ME, Ells G, Das UN, Horrobin DF. Differential killing of human carcinoma cells supplemented with n-3 and n-6 polyunsaturated fatty acids. J Natl Cancer Inst 1986; 77: 1053–62. DOI - PubMed - Google Scholar Shan B, Cai YZ, Sun M, Corke H. Antioxidant capacity of 26 spice extracts and characterization of their phenolic constituents. J Agric Food Chem. 2005; 53: 7749–59. DOI - PubMed - Google Scholar Matiax J, Quiles JL, Huertas JR, Battino M. Tissue specific interactions of exercise, dietary fatty acids, and vitamin E in lipid peroxidation. Free Radic Biol Med 1998; 24 : 511–21. DOI - PubMed - Google Scholar Dean RT, Fu S, Stocker R, Davies MJ. Biochemistry and pathology of radical-mediated protein oxidation. Biochem J 1997; 324: 1–8. PubMed - Google Scholar Bashir A, Perham RN, Scrutton NS, Berry A. Altering Kinetic mechanism and enzyme stability by mutagenesis of the dimmer interface of glutathione reductase. Biochem J 1995; 312: 527–33. PubMed - Google Scholar Perret-Gentil MI. Rat Biomethodology. Laboratory Animal Resources Center. The University of Texas at San Antonio. [Cited 1 Feb. 2015]. Available from: https://www.utdallas.edu/research/docs/rat_biomethodology/ Allen JW, Shuler CF, Menders RW, Olatt SA. A simplified technique for in vivo analysis of sister chromatid exchange using 50 bromodeoxyuridine tablets. Cytogenet Cell Genet 1977; 18: 231–7. DOI PubMed - Google Scholar Forsum U, Hallén A. Acridine orange staining of urethral and cervical smears for the diagnosis of gonorrhea. Acta Derm Venereol 1979; 59: 281–2. PubMed - Google Scholar Statistical Analysis System user's guide. Version 9.1. Cary, NC, USA: SAS Institute Inc.; 2012. Daham HH, Rahim SM, Al-Hmesh MJ. The effect of radiotherapy and chemotherapy in several physiological and biochemical parameters in cancer patients. Tikrit J Pure Sci 2012; 17: 83–91. Weijl N, Elseendoorm TJ, Lentjes EG, Hopman CD, Wipkink-Bakker A, Zwinderman AH, et al. Supplementation with antioxidant micronutrients and chemotherapy-induced toxicity in cancer patients treated with cisplatin-based chemotherapy: a randomised, double-blind placebo-controlled study. Eur J Cancer 2004; 40: 1713–23. DOI - PubMed - Google Scholar Al-Dalawy SS, Al-Salehy FK, Al-Sanafi AI. Efficient enzymatic antioxidants for oxidative stress syndrome in patients with hypertension. J Dhi Qar Sci 2008; 2: 32–3. Al-Helaly LA. Some antioxidant enzymes in workers exposed to pollutants. Raf J Sci 2011; 22: 29–38. Google Scholar Othman GO. Protective effects of linseed oil against methotrexate induced genotoxicity in bone marrow cells of albino mice Mus musculus. ZJPAS. 2016; 28: 49–53. Google Scholar Ashoka CH, Vijayalaxmi KK. Cytogenetic effects of methotrexate in bone marrow cells of Swiss albino mice. Int J Sci Res Edu 2016; 4: 4828–34. DOI - Google Scholar Rushworth D, Mathews A, Alpert A, Cooper Dihydrofolate reductase and thymidylate synthase transgenes resistant to methotrexate interact to permit novel transgene regulation. J Biol Chem 2015; 290: 22970–9. DOI - PubMed - Google Scholar Wong PT, Choi SK. Mechanisms and implications of dual-acting methotrexate in folate-targeted nanotherapeutic delivery. Int J Mol Sci 2015; 16: 1772–90. DOI - PubMed - Google Scholar Jafer ZMT, Shubber EK, Amash HS. Cytogenetic analysis of Chinese hamster lung fibroblasts spontaneously resistant to methotrexate. Nucleus 2001; 44: 28–35. Google Scholar Hussain ZK, AL-Mhdawi F, AL-Bakri N. Effect of methotrexate drug on some parameters of kidney in newborn mice. Iraqi J Sci 2014; 55: 968–73. Google Scholar Ghazi-Khansari M, Mohammadi-Bardbori A. Captopril ameliorates toxicity induced by paraquat in mitochondria isolated from the rat liver. Toxicol in Vitro 2007; 21: 403–7. DOI - PubMed - Google Scholar Dinic-olivira RJ, Sousa C, Remiao F, Durte JA, Navarro SA, Bastos L, et al. Full survival of paraquat-exposed rats after treatment with sodium salicylate. Free Radic Biol Med 2007; 42: 1017–28. DOI - PubMed - Google Scholar Attia AM, Nasr HM. Dimethoate-induced changes in biochemical parameters of experimental rat serum and its neutralization by black seed (Nigella sativa) oil. Slovak J Anim Sci 2009; 42: 87–94. Google Scholar Al-Rubaie AH.M. Effect of natural honey and mitomycin C on the effectiveness of the enzyme glutathione reductase in mice Mus musculus. Babylon Uni J 2008; 15: 1385–91.

Introduction Methods Resuts Discussion Conclusions Acknowledgments Authors' contributions Competing interests Ethical approval References Effect of Methotrexate and Omega-3 Combination on Cytogenetic Changes of Bone Marrow and Some Enzymatic Antioxidants: An Experimental Study Inaam N. Ali1, Muthana M. Awad2, Alaa S. Mahmood2,* 1 Water and Environment Directorate, Ministry of Sciences and Technology, Baghdad, Iraq 2 Department of Biology, College of Science, University of Anbar, Anbar, Iraq * Corresponding author: A. S. Mahmood (alaashm91@gmail.com) Abstract: Objective: To assess the effect of methotrexate and omega-3 combination on cytogenetic changes of bone marrow and activities of some enzymatic antioxidants. Methods: Fifty-six mature male Wistar rats were divided into two experimental groups and a control group. The first experimental group was sub-divided into three sub-groups depending on the concentration of methotrexate (MTX): X1 (0.05 mg/kg MTX), X2 (0.125 mg/kg MTX) and X3 (0.250 mg/kg MTX), which were given intraperitoneally on a weekly basis for eight weeks. The second experimental group (MTX and omega-3 group) was also sub-divided into three sub-groups (Y1, Y2 and Y3), which were injected intraperitoneally with 0.05, 0.125 and 0.25 mg/kg MTX, respectively, weekly for eight weeks accompanied by the oral administration of 300 mg/kg omega-3. The rats of the control group were given distilled water. The enzymatic activity of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) were measured in the sera of rats. In addition, the mitotic index (MI) and chromosomal aberrations of bone marrow were also studied. Results: MTX resulted in a significant decrease in the activities of CAT, SOD and GR compared to the controls. It also increased the MI and chromosomal aberrations of rat bone marrows. On the other hand, omega-3 significantly increased the activities of the investigated enzymatic antioxidants and reduced the MI and chromosomal aberrations in treated mice when given in combination with MTX. Conclusions: MTX has a genotoxic effect on the bone marrow by increasing the MI and all types of chromosomal aberrations and decreasing the enzymatic activity of CAT, SOD and GR. The addition of omega-3 can lead to a protective effect by reducing the toxic and mutagenic effects of MTX. Keywords: Methotrexate, Omega-3, Antioxidant, Wistar rat, Chromosomal aberration, Mitotic index 1. Introduction Methotrexate (MTX) is a folic acid antagonist because of their chemical similarity [1]. Vezmar et al. [2] showed that MTX affects the synthesis of nucleic acids deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) by interfering with the biosynthesis of thymine and purines. It also directly affects the rapidly dividing and intact cells, especially those in the mucous membranes of the mouth, intestine and bone marrow [3]. Omega-3 is a type of unsaturated fats, which are classified as essential fatty acids that cannot be manufactured by the body and should be taken with food [4]. Sources of omega-3 include fish oils, such as salmon, sardines and tuna, as well as soybeans, walnuts, raisins and linseed, almonds and olive oils [5]. Omega-3 is used in the prevention of a number of diseases such as rheumatoid arthritis, ulcerative colitis, asthma, atherosclerosis, cancer, and cardiovascular diseases [6]. A large amount of evidence indicates that omega-3 fatty acids have significant health benefits, including anti-inflammatory and antioxidant properties besides their effect on blood cholesterol levels [7]. Antioxidants retard the oxidation process by different mechanisms such as the removal of free radicals [8]. Enzymatic antioxidants include catalase (CAT), which is the first line of defense in the cell that removes hydrogen peroxide formed during biological processes by converting it into an aldehyde, and superoxide dismutase (SOD). There are three major families of SOD enzymes: manganese SOD (Mn-SOD) in the mitochondria and peroxisomes, iron SOD (Fe-SOD) in prokaryote cells and copper/zinc SOD (Cu-Zn SOD) in the cytoplasm of eukaryote cells [9]. Therefore, changes in the metal co-factors (manganese, iron, copper and zinc) can alter the effectiveness of SOD and may lead to diseases as a result of oxidative stress [10]. Glutathione reductase (GR) is also an enzymatic antioxidant that converts the oxidized glutathione to the reduced glutathione in the presence of NADPH, which is oxidized to NADP [11]. Therefore, the aim of the present study was to assess the effects of MTX and omega-3 on the cytogenetic changes of bone marrow as well as the activities of CAT, SOD and GR enzymatic antioxidants in male rats. 2. Method 2.1. Laboratory animals and experimental design Fifty-six mature male Wistar rats (Rattus norvegicus), aged 10–12 weeks old and weighing 250–300 gm, were used in the present study. The rats were kept in separate cages, with natural 13- hour light and 11-hour dark periods in a contamination-free environment with a controlled temperature (28.0 ± 1.0°C). In addition, rats were maintained on a standard diet and tap water ad libitum. The rats were randomly allocated to two experimental groups and a control group. The first experimental group (MTX group) included 24 rats injected intraperitoneally with different MTX dilutions with distilled water [12]. It was sub-divided into three sub-groups (eight rats per sub-group) according to MTX concentration as follows: X1 (0.05 mg/kg MTX), X2 (0.125mg/kg MTX) and X3 (0.25 mg/kg MTX). All rats were given a single dose of the specified MTX concentration weekly for eight weeks. The second experimental group (MTX and omega-3 group) included 24 rats allocated to three sub-groups (Y1, Y2 and Y3), which were injected intraperitoneally with 0.05, 0.125 and 0.25 mg/kg MTX, respectively, weekly for eight weeks accompanied by the oral administration of 300 mg/kg omega-3. The control group included eight rats that were intraperitoneally injected with distilled water and given a single dose of distilled water orally weekly for eight weeks. 2.2. Blood collection and processing After the end of the dosing period, 5 ml of blood were withdrawn from the heart (by cardiac puncture) using a 5 cc disposable syringe. The collected blood was immediately poured into a clean sterile screw-capped tube (plain tube) and left for coagulation in a water bath at 37°C for 15 minutes. After coagulation of blood, the plain tube was centrifuged for 5 minutes at 1500 rpm. Then the samples were stored at -20°C for subsequent analysis. 2.3. Measurement of the activity of antioxidant enzymes The antioxidant activities of CAT, SOD and GR were measured using enzyme-linked immunosorbent assay kits purchased from Kamiya Biomedical Company (Seattle, WA, US), according to the manufacturer's instructions. 2.4. Cytogenetic study of bone marrow Rats were killed by cervical dislocation, and their hip bones were cleaned from surrounding muscles and then dissected by cutting both ends of the bone. Five milliliters of physiological buffered saline were injected inside the bone to withdraw bone marrow into a test tube. Tubes were centrifuged at 2000 rpm/10 minutes. The supernatant was then removed, and 10 ml of KCL solution (0.075 M) were added to the sediment. The mixture was then incubated at 37 °C in a water bath for 30 minutes, with shaking from time to time. The tubes were then centrifuged at 2000rpm/10 minutes to remove the supernatant. However, 5 ml of a freshly prepared fixative solution (methanol: glacial acetic acid 1:3) were added gradually in the form of droplets into the inner wall of the tube with constant mixing. After that, the tubes were placed at 4 °C for half an hour to fix the cells. This process was repeated for three times, and the cells were then suspended in 2 ml of the fixative solution. The tubes were centrifuged at 2000 rpm for 5 minutes, and the supernatant was then removed while the cells were re-suspended in 1-2 ml of cold fixative solution. After shaking the tubes, 4–5 drops were then taken from each tube onto a clean slide from a height of about three feet to provide an opportunity for the cells and nuclei to spread well. The slides were stained with acridine orange solution (0.01%) for 4–5 minutes, incubated in Sorensen’s buffer (0.06M, pH 6.5) for a minute. and then examined using a fluorescence microscope Olympus BX 51 America at a wavelength of 450–500 nm [13, 14]. A total of 1000 cells were examined, and both dividing and non-dividing cells were calculated [13]. Mitotic index (MI) was calculated according to the following formula [13]: MI= No. of dividing cells / 1000 × 100 2.5. Analysis of chromosomal aberrations of bone marrow cells A total of 1000 dividing cells were examined on the stained slides under a fluorescence microscope at a wavelength of 45–500 nm. The examined cells were at the first metaphase of the mitotic division, where chromosomal aberrations are clear and can be easily seen [13]. 2.6. Statistical analysis Data were analyzed using the Statistical Analysis System (SAS®) software, version 9.1 (Cary, NC, USA) [15]. Effects were expressed as mean ± standard error (SE) and statistically compared using a completely randomized design analysis of variance and least significant differences. Differences at P values <5 were considered statistically significant. 3. Results 3.1. Effects of MTX and MTX-omega-3 combination on antioxidant enzymatic activities Table (1) shows significantly lower SOD activities among rats treated with MTX or MTX-omega-3 compared to controls. Moreover, sera of rats receiving relatively high doses of MTX (sub-groups X2 and X3) showed the lowest enzymatic activities of 4.29 ± 0.01 IU and 3.93 ± 0.11 IU, respectively. On the other hand, CAT activity differed significantly between treated and control rats as well as among treated rats themselves, In this respect, the controls showed the highest activity of 39.38 ±0.02 IU, while those receiving the highest MTX concentration, either alone or in combination with omega-3 (sub-groups X3 and Y3), showed the lowest activities of 30.97 ± 0.03 IU and 32.12± 0.06 IU, respectively. Regarding GR activity, control rats showed a higher activity of 53.09± 0.05 IU compared to treated ones; however, the differences in GR activities in rats given low doses of MTX, either alone or in combination with omega-3 (sub-groups X1 and Y1), were not statistically significant. On the other hand, rats in sub-groups X3 and Y3 showed the lowest GR activities of 34.59 ± 0.63 IU and 37.15 ±0.01, respectively, with statistically significant differences from other sub-groups. 3.2. Effects of MTX and MTX-omega-3 combination on mitotic index of bone marrow cells Figure (1) shows a significant decrease in the MI in all treated groups compared to control. In addition, there was a reverse association between MTX concentration and MI, where rats treated with the highest dose of MTX (sub-group X3) showed a significant decrease in MI compared to all other treated rat sub-groups. In addition, rats in sub-groups treated with MTX and omega-3 (sub-groups Y1, Y2 and Y3) showed a significant increase in MI compared to their counterpart rats receiving MTX only. Table 1. Activity of antioxidant enzymes in rats treated with MTX and MTX-omega-3 Group Enzymatic activity (mean± SE) SOD (IU) CAT (IU) GR (µmol) Control 6.41±0.02 a 39.38±0.02 a 53.09±0.05 a X1 (0.05 mg MTX/ kg) 5.33±0.01 b 37.81±0.01 c 51.12±0.06 a Y1 (0.05 mg MTX + 300 mg omega-3/ kg) 6.08±0.04 a 38.40±0.02 b 51.97±0.03 a X2 (0.125 mg MTX/ kg) 4.29±0.01 cd 33.13±0.01 e 42.34±0.03 b Y2 (0.125 mg MTX + 300 mg omega-3/ kg) 4.99±0.40 b 36.68±0.02 d 43.02±3.04 b X3 (0.25 mg MTX/ kg) 3.93±0.11 d 30.97±0.03 g 34.59±0.63 c Y3 (0.25 mg MTX + 300 mg omega-3/ kg) 4.47±0.02 c 32.12±0.06 f 37.15±0.01 c SE, Standard error; IU, international unit; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; *statistically significant at P < 0.05; **statistically significant at P < 0.01. Means with different letters within the same column showed a statistically significant difference. 3.3. Effects of MTX and MTX-omega-3 combination on chromosomal aberrations of bone marrow cells Rats receiving higher concentrations of MTX (sub-group X3) showed a significant increase in all types of chromosomal aberrations, i.e., chromatid gaps, chromosome gaps, chromatid breaks, chromosome breaks, deletions and simple fragments (Figure 2 and Table 2) than those of the control group or other treated sub-groups. All rats treated with MTX-omega-3 combination showed a significant decrease in almost all types of chromosomal aberrations compared to their counterpart rats receiving MTX alone (Table 2). Figure 1. Effect of MTX and MTX-omega-3 on the MI of bone marrow cells of treated rats compared to the controls. The groups X1 (0.05 MTX), X2 (0.125 MTX) and X3 (0.250 MTX) were compared to the control group, while the groups Y1 (0.05 MTX+ omega-3), Y2 (0.125 MTX+ omega-3) and Y3 (0.25 MTX+ omega-3) were compared to X1, X2 and X3, respectively. Figure 2. Effect of MTX and MTX-omega-3 on chromosomal aberration as seen under fluorescence microscope after staining with acridine orange: (1) a simple fragment; (2) a chromatid gap; (3) a chromosomal gap (A) and a chromosomal break (B). 4. Discussion The present experiment reveals that the addition of omega-3 to MTX alleviates its effects on the activities of the antioxidant enzymes CAT, SOD and GR, and decreases the MI as well as all types of chromosomal aberrations in the bone marrow cells. Daham et al. [16] showed that the decline in antioxidants associated with chemotherapy is attributed to the increase in lipid peroxidation caused by these kinds of drugs, which increase the level of free radicals. In addition, Weijl et al. [17] showed that some chemotherapeutic drugs have a negative effect on the antioxidant levels such as GR, whose activity decreases as a result of its involvement in many cellular processes such as cell defenses against the toxicity of some compounds. Al-Dalawy et al. [18] found that the decrease in the level of SOD is an evidence of its increased activity due to the increased release of free radicals. MTX causes an increase in the release of free radicals, including the OH radical that causes direct damage to DNA [16]. Al-Helaly [19] showed that the amount of food taken has an effect on antioxidants, where nutritional deficiency decreases the antioxidant levels, thus increasing free radicals that cause damage to DNA. Table 2. Chromosomal aberrations of bone marrow cells in rats treated with MTX and MTX-omega-3 Group Type of chromosomal aberration(mean ± SE) Chromatid gap Chromosome Gap Chromatid breaks Chromosome breaks Deletion Simple Fragments Chromosomal aberration (%) Control 1.33±0.33 e 0.00±0.00 e 1.67±0.33 c 0.33±0.15 c 0.00±0.00 0.67±0.33 cd 0.04±0.005 f X1 2.75±0.47 cd 1.50±0.28 cd 2.50±0.64 bc 1.00±0.41 bc 0.50±0.28 bc 0.75±0.25 bcd 0.09±0.02 de Y1 1.75±0.47 de 0.75±0.25 de 1.50±0.28 c 1.00±0.00 bc 0.75±0.25 abc 0.75±0.25 abc 0.065±0.005 ef X2 4.67±0.33 b 2.67±0.33 ab 2.67±0.33 bc 1.67±0.33 ab 0.67±0.33 abc 1.67±0.33 ab 0.14±0.006 bc Y2 3.00±0.00 c 2.00±0.00 bc 3.00±0.057 bc 1.33±0.33 b 0.67±0.33 abc 0.33±0.15 d 0.106±0.003 cd X3 6.80±0.37 a 3.00±0.31 a 4.60±0.74 a 2.40±0.24 a 1.40±0.24 a 1.80±0.37 a 0.20±0.017 a Y3 5.60±0.40 ab 2.40±0.24 ab 3.60±0.24 ab 1.80±0.20 ab 1.20±0.20 ab 1.40±0.24 abc 0.16±0.003 b LSD 1.231** 0.814** 0.602** 0.841** 0.774* 0.941** 3.499* SE, Standard error; * statistically significant at P < 0.05; ** statistically significant at P < 0.01. Means with different letters within the same column showed a statistically significant difference. X1 (0.05 mg MTX/ kg); X2 (0.125 mg MTX/ kg); X3 (0.25 mg MTX/ kg); Y1 (0.05 mg MTX + 300 mg omega-3/ kg); Y2 (0.125 mg MTX + 300 mg omega-3/ kg); Y3 (0.25 mg MTX + 300 mg omega-3/ kg). In the present study, the intraperitoneal administration of MTX to rats also caused a decrease in the MI of bone marrow and a significant increase in the rate of abnormal chromosomal aberration compared to the control rats. This finding is consistent with those reported previously [20], [21]. The effect of MTX can be attributed to its ability to interfere with the genetic material, leading to the appearance of toxic and mutagenic consequences. Rushworth et al. [22] reported that MTX leads to a lack of dihydrofolate reductase, which is the key to the growth and cell division processes. This, in turn, leads to a reduction of the nucleotides involved in the building of DNA and, therefore, to a stop or obstruction of the repair mechanisms of the damaged DNA. In addition, Wong and Choi [23] concluded that MTX inhibits the action of enzymes controlling the purine metabolism, which leads to the accumulation of adenosine in addition to the damage of the molecule itself and to the occurrence of chromosomal aberrations. Jafer et al. [24] reported the ability of MTX to induce chromosomal aberration in humans or animals by preventing the repair of DNA and affecting the proteins found in chromosomes. These findings were also confirmed by Hussain et al. [25], who found that MTX causes an increase in chromosomal aberrations. In the present study, the MI showed a significant increase in rat sub-groups treated with MTX-omega-3 combination, but there was a decrease in the rate of chromosomal aberration, which confirms the role of omega-3 unsaturated fatty acids in protecting the cell from the impact of free radicals [26], [27]. Attia and Nasr [28] reported the antioxidant effect of omega-3, which was attributed to the reduction in lipid peroxidation and the increase in SOD and CAT or the stimulation of GR. It is noteworthy that GR leads to the synthesis of reduced glutathione, which is important in the defense of the cell against toxic substances and the prevention of the occurrence of mutations [29]. 5. Conclusions MTX significantly decreases the activity of enzymatic antioxidants, reduce the MI and increase the chromosomal aberrations of all types in bone marrow. This gives further evidence on the genotoxic effects of MTX on the bone marrow. On the other hand, omega-3 shows a protective effect by reducing the toxic and mutagenic effects of MTX. Acknowledgments The authors thank the staff of the Water and Environment Directorate, Ministry of Science and Technology, Baghdad, Iraq for their cooperation. They also thank Dr. Jasim Al-Niami for his technical and scientific guidance. Authors' contributions INA, MMA and ASM contributed to the study design and analyzed data. All authors contributed to the manuscript drafting and revising and approved the final submission. Competing interests The authors declare that they have no competing interests associated with this article. Ethical approval The ethical clearance of this study was obtained from the Ethics Committee of the College of Science, University of Anbar (Reference No. A. D. 51 in 30/8/2015). References Yuen CW, Winter ME. Methotrexate (MTX). In: Basic clinical pharmacokinetics, Winter ME, editor. Philadelphia, USA: Lippincott Williams & Wilkins; 2010. p.p. 304–25. Google Scholar Vezmar S, Becker A, Bode U, Jaehde U. Biochemical and clinical aspects of methotrexate neurotoxicity. Chemotherapy 2003; 49: 92–104. DOI PubMed - Google Scholar Tian H, Cronstein BN. Understanding the mechanisms of action of methotrexate implications for the treatment of rheumatoid arthritis. Bull NYU Hosp Jt Dis 2007; 65: 168–73. PubMed - Google Scholar El-Khayat Z, Rasheed WI, Elias T, Hussein J, Oraby F, Badawi M, et al. Protective effect of either dietary or pharmaceutical n-3 fatty acids on bone loss in ovariectomized rats. Maced J Med Sci 2010; 3: 9–16. DOI - Google Scholar Kris-Etherton PM, Harris WS, Appel LJ; Nutrition Committee. Fish consumption, fish oil, omega-3 fatty acids and cardiovascular disease. Arterioscler Thromb Vasc Biol 2003; 23: e20–30. DOI - PubMed - Google Scholar Calder PC. Polyunsaturated fatty acids and inflammation. Prostaglandins Leukot Essent Fatty Acids 2006; 75: 197–202. DOI - PubMed - Google Scholar Begin ME, Ells G, Das UN, Horrobin DF. Differential killing of human carcinoma cells supplemented with n-3 and n-6 polyunsaturated fatty acids. J Natl Cancer Inst 1986; 77: 1053–62. DOI - PubMed - Google Scholar Shan B, Cai YZ, Sun M, Corke H. Antioxidant capacity of 26 spice extracts and characterization of their phenolic constituents. J Agric Food Chem. 2005; 53: 7749–59. DOI - PubMed - Google Scholar Matiax J, Quiles JL, Huertas JR, Battino M. Tissue specific interactions of exercise, dietary fatty acids, and vitamin E in lipid peroxidation. Free Radic Biol Med 1998; 24 : 511–21. DOI - PubMed - Google Scholar Dean RT, Fu S, Stocker R, Davies MJ. Biochemistry and pathology of radical-mediated protein oxidation. Biochem J 1997; 324: 1–8. PubMed - Google Scholar Bashir A, Perham RN, Scrutton NS, Berry A. Altering Kinetic mechanism and enzyme stability by mutagenesis of the dimmer interface of glutathione reductase. Biochem J 1995; 312: 527–33. PubMed - Google Scholar Perret-Gentil MI. Rat Biomethodology. Laboratory Animal Resources Center. The University of Texas at San Antonio. [Cited 1 Feb. 2015]. Available from: https://www.utdallas.edu/research/docs/rat_biomethodology/ Allen JW, Shuler CF, Menders RW, Olatt SA. A simplified technique for in vivo analysis of sister chromatid exchange using 50 bromodeoxyuridine tablets. Cytogenet Cell Genet 1977; 18: 231–7. DOI PubMed - Google Scholar Forsum U, Hallén A. Acridine orange staining of urethral and cervical smears for the diagnosis of gonorrhea. Acta Derm Venereol 1979; 59: 281–2. PubMed - Google Scholar Statistical Analysis System user's guide. Version 9.1. Cary, NC, USA: SAS Institute Inc.; 2012. Daham HH, Rahim SM, Al-Hmesh MJ. The effect of radiotherapy and chemotherapy in several physiological and biochemical parameters in cancer patients. Tikrit J Pure Sci 2012; 17: 83–91. Weijl N, Elseendoorm TJ, Lentjes EG, Hopman CD, Wipkink-Bakker A, Zwinderman AH, et al. Supplementation with antioxidant micronutrients and chemotherapy-induced toxicity in cancer patients treated with cisplatin-based chemotherapy: a randomised, double-blind placebo-controlled study. Eur J Cancer 2004; 40: 1713–23. DOI - PubMed - Google Scholar Al-Dalawy SS, Al-Salehy FK, Al-Sanafi AI. Efficient enzymatic antioxidants for oxidative stress syndrome in patients with hypertension. J Dhi Qar Sci 2008; 2: 32–3. Al-Helaly LA. Some antioxidant enzymes in workers exposed to pollutants. Raf J Sci 2011; 22: 29–38. Google Scholar Othman GO. Protective effects of linseed oil against methotrexate induced genotoxicity in bone marrow cells of albino mice Mus musculus. ZJPAS. 2016; 28: 49–53. Google Scholar Ashoka CH, Vijayalaxmi KK. Cytogenetic effects of methotrexate in bone marrow cells of Swiss albino mice. Int J Sci Res Edu 2016; 4: 4828–34. DOI - Google Scholar Rushworth D, Mathews A, Alpert A, Cooper Dihydrofolate reductase and thymidylate synthase transgenes resistant to methotrexate interact to permit novel transgene regulation. J Biol Chem 2015; 290: 22970–9. DOI - PubMed - Google Scholar Wong PT, Choi SK. Mechanisms and implications of dual-acting methotrexate in folate-targeted nanotherapeutic delivery. Int J Mol Sci 2015; 16: 1772–90. DOI - PubMed - Google Scholar Jafer ZMT, Shubber EK, Amash HS. Cytogenetic analysis of Chinese hamster lung fibroblasts spontaneously resistant to methotrexate. Nucleus 2001; 44: 28–35. Google Scholar Hussain ZK, AL-Mhdawi F, AL-Bakri N. Effect of methotrexate drug on some parameters of kidney in newborn mice. Iraqi J Sci 2014; 55: 968–73. Google Scholar Ghazi-Khansari M, Mohammadi-Bardbori A. Captopril ameliorates toxicity induced by paraquat in mitochondria isolated from the rat liver. Toxicol in Vitro 2007; 21: 403–7. DOI - PubMed - Google Scholar Dinic-olivira RJ, Sousa C, Remiao F, Durte JA, Navarro SA, Bastos L, et al. Full survival of paraquat-exposed rats after treatment with sodium salicylate. Free Radic Biol Med 2007; 42: 1017–28. DOI - PubMed - Google Scholar Attia AM, Nasr HM. Dimethoate-induced changes in biochemical parameters of experimental rat serum and its neutralization by black seed (Nigella sativa) oil. Slovak J Anim Sci 2009; 42: 87–94. Google Scholar Al-Rubaie AH.M. Effect of natural honey and mitomycin C on the effectiveness of the enzyme glutathione reductase in mice Mus musculus. Babylon Uni J 2008; 15: 1385–91.

We review our recent work on optical biosensors based on microring resonators (MRR) integrated with 4x4 multimode interference (MMI) couplers for multichannel and highly sensitive chemical and biological sensors. The proposed sensor structure has advantages of compactness, high sensitivity compared with the reported sensing structures. By using the transfer matrix method (TMM) and numerical simulations, the designs of the sensor based on silicon waveguides are optimized and demonstrated in detail. We applied our structure to detect glucose and ethanol concentrations simultaneously. A high sensitivity of 9000 nm/RIU, detection limit of 2x10-4 for glucose sensing and sensitivity of 6000nm/RIU, detection limit of 1.3x10-5 for ethanol sensing are achieved. Keywords Biological sensors, chemical sensors, optical microring resonators, high sensitivity, multimode interference, transfer matrix method, beam propagation method (BPM), multichannel sensor References [1] Vittorio M.N. 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Leonardis, "Ammonia Optical Sensing by Microring Resonators," Sensors, vol. 7, pp. 2741-2749, 2007.[8] C. Lerma Arce, K. De Vos, T. Claes et al., "Silicon-on-insulator microring resonator sensor integrated on an optical fiber facet," IEEE Photonics Technology Letters, vol. 23, pp. 890 - 892, 2011.[9] Trung-Thanh Le, "Realization of a Multichannel Chemical and Biological Sensor Using 6x6 Multimode Interference Structures," International Journal of Information and Electronics Engineering, Singapore, vol. 2, pp. 240-244, 2011.[10] Trung-Thanh Le, "Microring resonator Based on 3x3 General Multimode Interference Structures Using Silicon Waveguides for Highly Sensitive Sensing and Optical Communication Applications," International Journal of Applied Science and Engineering, vol. 11, pp. 31-39, 2013.[11] K. De Vos, J. Girones, T. 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Soldano and E.C.M. Pennings, "Optical multi-mode interference devices based on self-imaging :principles and applications," IEEE Journal of Lightwave Technology, vol. 13, pp. 615-627, Apr 1995.[22] Trung-Thanh Le, Multimode Interference Structures for Photonic Signal Processing: LAP Lambert Academic Publishing, 2010.[23] J.M. Heaton and R.M. Jenkins, " General matrix theory of self-imaging in multimode interference(MMI) couplers," IEEE Photonics Technology Letters, vol. 11, pp. 212-214, Feb 1999 1999.[24] Trung-Thanh Le and Laurence Cahill, "Generation of two Fano resonances using 4x4 multimode interference structures on silicon waveguides," Optics Communications, vol. 301-302, pp. 100-105, 2013.[25] W. Green, R. Lee, and G. DeRose et al., "Hybrid InGaAsP-InP Mach-Zehnder Racetrack Resonator for Thermooptic Switching and Coupling Control," Optics Express, vol. 13, pp. 1651-1659, 2005.[26] Trung-Thanh Le and Laurence Cahill, "The Design of 4×4 Multimode Interference Coupler Based Microring Resonators on an SOI Platform," Journal of Telecommunications and Information Technology, Poland, pp. 98-102, 2009.[27] Duy-Tien Le, Manh-Cuong Nguyen, and Trung-Thanh Le, "Fast and slow light enhancement using cascaded microring resonators with the Sagnac reflector," Optik - International Journal for Light and Electron Optics, vol. 131, pp. 292–301, Feb. 2017.[28] Xiaoping Liang, Qizhi Zhang, and Huabei Jiang, "Quantitative reconstruction of refractive index distribution and imaging of glucose concentration by using diffusing light," Applied Optics, vol. 45, pp. 8360-8365, 2006/11/10 2006.[29] C. Ciminelli, F. Dell’Olio, D. Conteduca et al., "High performance SOI microring resonator for biochemical sensing," Optics & Laser Technology, vol. 59, pp. 60-67, 2014.[30] Trung-Thanh Le, "Two-channel highly sensitive sensors based on 4 × 4 multimode interference couplers," Photonic Sensors, pp. 1-8, DOI: 10.1007/s13320-017-0441-1, 2017.[31] O. A. Marsh, Y. Xiong, and W. N. Ye, "Slot Waveguide Ring-Assisted Mach–Zehnder Interferometer for Sensing Applications," IEEE Journal of Selected Topics in Quantum Electronics, vol. 23, pp. 440-443, 2017.[32] Juejun Hu, Xiaochen Sun, Anu Agarwal et al., "Design guidelines for optical resonator biochemical sensors," Journal of the Optical Society of America B, vol. 26, pp. 1032-1041, 2009/05/01 2009.[33] Y. Chen, Y. L. Ding, and Z. Y. Li, "Ethanol Sensor Based on Microring Resonator," Advanced Materials Research, vol. 655-657, pp. 669-672, 2013.[34] Sasikanth Manipatruni, Rajeev K. Dokania, Bradley Schmidt et al., "Wide temperature range operation of micrometer-scale silicon electro-optic modulators," Optics Letters, vol. 33, pp. 2185-2187, 2008.[35] Ming Han and Anbo Wang, "Temperature compensation of optical microresonators using a surface layer with negative thermo-optic coefficient," Optics Letters, vol. 32, pp. 1800-1802, 2007.[36] Kristinn B. Gylfason, Albert Mola Romero, and Hans Sohlström, "Reducing the temperature sensitivity of SOI waveguide-based biosensors," 2012, pp. 84310F-84310F-15.[37] Chun-Ta Wang, Cheng-Yu Wang, Jui-Hao Yu et al., "Highly sensitive optical temperature sensor based on a SiN micro-ring resonator with liquid crystal cladding," Optics Express, vol. 24, pp. 1002-1007, 2016.[38] Feng Qiu, Feng Yu, Andrew M. Spring et al., "Athermal silicon nitride ring resonator by photobleaching of Disperse Red 1-doped poly(methyl methacrylate) polymer," Optics Letters, vol. 37, pp. 4086-4088, 2012.[39] Biswajeet Guha, Bernardo B. C. 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Background: Reperfusion following ischemia can lead to more injuries than ischemia itself especially in diabetic patients. The aim of this study was to evaluate the effect of dexmedetomidine on ischemia-reperfusion injury (IRI) in rats with have hepatic IRI and diabetes mellitus. Methodology: Twenty-eight Wistar Albino rats were randomised into four groups as control (C), diabetic (DC), diabetic with hepatic ischemia-reperfusion injury (DIR), and diabetic but administered dexmedetomidine followed by hepatic IRI (DIRD) groups. Hepatic tissue samples were evaluated histopathologically by semiquantitative methods. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathion s-transpherase (GST), and catalase (CAT) enzyme levels were investigated in liver and kidney tissues as oxidative state parameters. Results: In Group DIR; hepatocyte degeneration, sinusoidal dilatation, pycnotic nucleus, and necrotic cells were found to be more in rat hepatic tissue; while mononuclear cell infiltration was higher in the parenchyme. MDA levels were significantly lower; but SOD levels were significantly higher in Group DIRD with regard to Group DIR. In the IRI induced diabetic rats’ hepatic and nephrotic tissues MDA levels, showing oxidative injury, were found to be lower. SOD levels, showing early antioxidant activity, were higher. Conclusion: The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease IRI. Key words: Hepatic ischemia reperfusion injury; Diabetes mellitus; Dexmedetomidine; Rat; MDA; SOD Citation: Sezen SC, Işık B, Bilge M, Arslan M, Çomu FM, Öztürk L, Kesimci E, Kavutçu M. Effect of dexmedetomidine on ischemia-reperfusion injury of liver and kidney tissues in experimental diabetes and hepatic ischemia-reperfusion injury induced rats. Anaesth Pain & Intensive Care 2016;20(2):143-149 Received: 21 November 2015; Reviewed: 10, 24 December 2015, 9, 10 June 2016; Corrected: 12 December 2015; Accepted: 10 June 2016 INTRODUCTİON Perioperative acute tissue injury induced by ischemia-reperfusion is a comman clinical event caused by reduced blood supply to the tissue being compromised during major surgery. Ischemia leads to cellular injury by depleting cellular energy deposits and resulting in accumulation of toxic metabolites. The reperfusion of tissues that have remained in ischemic conditions causes even more damage.1 Furthermore hepatic ischemia-reperfusion injury (IRI) demonstrates a strong relationship with peri-operative acute kidney injury.2 The etiology of diabetic complications is strongly associated with increased oxidative stress (OS). Diabetic patients are known to have a high risk of developing OS or IRI which results with tissue failure.3 The most important role in ischemia and reperfusion is played by free oxygen radicals.1 In diabetes, characterized by hyperglycemia, even more free oxygen radicals are produced due to oxidation of glucose and glycosylation of proteins.3 The structures which are most sensitive to free oxygen radicals in the cells are membrane lipids, proteins, nucleic acids and deoxyribonucleic acids.1 It has been reported that endogenous antioxidant enzymes [superoxide dismutase (SOD), glutathion s-transpherase (GST), catalase (CAT)] play an important role to alleviate IRI.4-8 Also some pharmacological agents have certain effects on IRI.1 The anesthetic agents influence endogenous antioxidant systems and free oxygen radical formation.9-12 Dexmedetomidine is a selective α-2 adrenoceptor agonist agent. It has been described as a useful and safe adjunct in many clinical applications. It has been found that it may increase urine output by considerably redistributing cardiac output, inhibiting vasopressin secretion and maintaining renal blood flow and glomerular filtration. Previous studies demonstrated that dexmedetomidine provides protection against renal, focal cerebral, cardiac, testicular, and tourniquet-induced IRI.13-18 Arslan et al observed that dexmedetomidine protected against lipid peroxidation and cellular membrane alterations in hepatic IRI, when given before induction of ischemia.17 Si et al18 demonstrated that dexmedetomidine treatment results in a partial but significant attenuation of renal demage induced by IRI through the inactivation of JAK/STAT signaling pathway in an in vivo model. The efficacy of the dexmedetomidine for IRI in diabetic patient is not resarched yet. The purpose of this experimental study was to evaluate the biochemical and histological effects of dexmedetomidine on hepatic IRI in diabetic rat’s hepatic and renal tissue. METHODOLOGY Animals and Experimental Protocol: This study was conducted in the Physiology Laboratory of Kirikkale University upon the consent of the Experimental Animals Ethics Committee of Kirikkale University. All of the procedures were performed according to the accepted standards of the Guide for the Care and Use of Laboratory Animals. In the study, 28 male Wistar Albino rats, weighing between 250 and 300 g, raised under the same environmental conditions, were used. The rats were kept under 20-21 oC at cycles of 12-hour daylight and 12-hour darkness and had free access to food until 2 hours before the anesthesia procedure. The animals were randomly separated into four groups, each containing 7 rats. Diabetes was induced by a single intraperitoneal injection of streptozotocin (Sigma Chemical, St. Louis, MO, USA) at a dose of 65 mg/kg body weight. The blood glucose levels were measured at 72 hrs following this injection. Rats were classified as diabetic if their fasting blood glucose (FBG) levels exceeded 250 mg/dl, and only animals with FBGs of > 250 mg/dl were included in the diabetic groups (dia­betes only, diabetes plus ischemia-reperfusion and diabetes plus dexmedetomidine-ischemia-reperfusion). The rats were kept alive 4 weeks after streptozotocin injection to allow development of chronic dia­betes before they were exposed to ischemia-reperfusion.(19) The rats were weighed before the study. Rats were anesthetized with intraperitoneal ketamine 100 mg/kg. The chest and abdomen were shaved and each animal was fixed in a supine position on the operating table. The abdomen was cleaned with 1% polyvinyl iodine and when dry, the operating field was covered with a sterile drape and median laparotomy was performed. There were four experimental groups (Group C (sham-control; n = 7), (Group DC (diabetes-sham-control; n = 7), Group DIR (diabetes-ischemia-reperfusion; n = 7), and Group DIRD (diabetes-ischemia-reperfusion-dexmedetomidine; n = 7). Sham operation was performed on the rats in Group C and Group DC. The sham operation consisted of mobilization of the hepatic pedicle only. The rats in this group were sacrificed 90 min after the procedure. Hepatic I/R injury was induced in Groups DIR and DIRD respectively with hepatic pedicle clamping using a vascular clamp as in the previous study of Arslan et al.(17) After an ischemic period of 45 min, the vascular clamp was removed. A reperfusion period was maintained for 45 min. In Group DIRD, dexmedetomidine hydrochloride 100 μg/kg, (Precedex 100 μg/2 ml, Abbott®, Abbott Laboratory, North Chicago, Illinois, USA) was administrated via intraperitoneal route 30 minutes before surgery. All the rats were given ketamine 100 mg/kg intraperitoneally and intracardiac blood samples were obtained. Preserving the tissue integrity by avoiding trauma, liver and renal biopsy samples were obtained. Biochemical Analysis: The liver and renal tissues were first washed with cold deionized water to discard blood contamination and then homogenized in a homogenizer. Measurements on cell contest require an initial preparation of the tissues. The preparation procedure may involve grinding of the tissue in a ground glass tissue blender using a rotor driven by a simple electric motor. The homogenizer as a tissue blender similar to the typical kitchen blender is used to emulsify and pulverize the tissue (Heidolph Instruments GMBH & CO KGDiax 900 Germany®) at 1000 U for about 3 min. After centrifugation at 10,000 g for about 60 min, the upper clear layer was taken. MDA levels were determined using the method of Van Ye et al,(20) based on the reaction of MDA with thiobarbituric acid (TBA). In the TBA test reaction, MDA and TBA react in acid pH to form a pink pigment with an absorption maximum at 532 nm. Arbitrary values obtained were compared with a series of standard solutions (1,1,3,3-tetraethoxypropane). Results were expressed as nmol/mg.protein. Part of the homogenate was extracted in ethanol/chloroform mixture (5/3 v/v) to discard the lipid fraction, which caused interferences in the activity measurements of T-SOD, CAT and GST activities. After centrifugation at 10.000 x g for 60 min, the upper clear layer was removed and used for the T-SOD, CAT, GST enzyme activity measurement by methods as described by Durak et al21, Aebi22 and Habig et al23 respectively. One unit of SOD activity was defined as the enzyme protein amount causing 50% inhibition in NBTH2 reduction rate and result were expressed in U/mg protein. The CAT activity method is based on the measurement of absorbance decrease due to H2O2 consumption at 240 nm. The GST activity method is based on the measurement of absorbance changes at 340 nm due to formation of GSH-CDNB complex. Histological determinations: Semiquantitative evaluation technique used by Abdel-Wahhab et al(24) was applied for interpreting the structural changes investigated in hepatic tissues of control and research groups. According to this, (-) (negative point) represents no structural change, while (+) (one positive point) represents mild, (++) (two positive points) medium and (+++) (three positive points) represents severe structural changes. Statistical analysis: The Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA) 20.0 softwre was used for the statistical analysis. Variations in oxidative state parameters, and histopathological examination between study groups were assessed using the Kruskal-Wallis test. The Bonferroni-adjusted Mann-Whitney U-test was used after significant Kruskal-Wallis to determine which groups differed from the others. Results were expressed as mean ± standard deviation (Mean ± SD). Statistical significance was set at a p value < 0.05 for all analyses. RESULTS There was statistically significant difference observed between the groups with respect to findings from the histological changes in the rat liver tissue (hepatocyte degeneration, sinüsoidal dilatation, pycnotic nucleus, prenecrotic cell) determined by light microscopy according to semiquantitative evaluation techniques (p < 0.0001). In Group DIR, hepatocyte degeneration was significantly high compared to Group C, Group DC and Group DIRD (p < 0.0001, p < 0.0001, p = 0.002, respectively), (Table 1, Figure 1-4). Similarly, sinüsoidal dilatation was significantly higher in Group DIR (p < 0.0001, p = 0.004, p = 0.015, respectively). Although, pcynotic nucleus was decreased in Group DIRD, it did not make a significant difference in comparison to Group DIR (p = 0.053), (Table 1, Figure 1-4). The prenecrotic cells were significantly increased in Group DIR, with respect to Group C, Group DC and Group DIRD (p < 0.0001, p = 0.004, p < 0.0001, respectively), (Table 1, Figure 1-4). Table 1. The comparison of histological changes in rat hepatic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR Figure 1: Light microscopic view of hepatic tissue of Group C (control). VC: vena centralis, *: sinusoids. ®: hepatocytes, k: Kupffer cells, G: glycogen granules, mc: minimal cellular changes, Hematoxilen & Eosin x 40 Figure 2: Light-microscopic view of hepatic tissue of Group DC (diabetes mellitus control) (G: Glycogen granules increased in number, (VC: vena centralis, *:sinusoids. ®:hepatocytes, k:Kupffer cells, G: glycogen granules, mc: minimal cellular changes; Hematoxylin & Eosin x 40) Figure 3: Light-microscopic view of hepatic tissue of Group DIR (Diabetes Mellitus and ischemia-reperfusion) (VC: vena centralis, (H) degenerative and hydrophic hepatocytes, (dej) vena centralis degeneration (centrolobar injury) (*): sinusoid dilatation. (←) pycnotic and hyperchromatic nuclei, MNL: mononuclear cell infiltration, (¯) congestion, K: Kupffer cell hyperplasia, (­) vacuolar degeneration (Hematoxylin & Eosin x 40) Figure 4: Light-microscopic view of hepatic tissue of Group DIRD (Diabetes Mellitus and ischemia-reperfusion together with dexmedetomidine applied group) (VC: vena centralis, (MNL) mononuclear cell infiltration, (dej) hydrophilic degeneration in hepatocytes around vena centralis, (conj) congestion, G: glycogen granules, (←) pycnotic and hyperchromatic nuclei, sinusoid dilatation (*) (Hematoxylin & Eosin x 40) Besides, in liver tissue parenchyma, MN cellular infiltration was a light microscopic finding; and showed significant changes among the groups (p < 0.0001). This was significantly higher in Group DIR, compared to Group C, DC, and DIRD (p < 0.0001, p=0.007, p = 0.007, respectively), (Table 1, Figure 1-4). The enzymatic activity of MDA, SOD and GST in hepatic tissues showed significant differences among the groups [(p = 0.019), (p = 0.034). (p = 0.008) respectively]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p = 0.011, p = 0.016, respectively), (Table 2). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.010, p = 0.038, respectively), (Table 2). The GST enzyme activity was significantly higher in Group DIR, when compared to Group C, DC and DIRD (p = 0.007, p = 0.038, p = 0.039, respectively), (Table 2). Table 2. Oxidative state parameters in rat hepatic tissue [Mean ± SD] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR The enzymatic activity of MDA, SOD in renal tissues, showed significant differences among the groups [(p < 0.0001), (p = 0.008) respectively ]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p < 0.0001, p < 0.0001, respectively). Also MDA enzyme activity level was significantly increased in Group DC, in comparison to Group C and Group DIRD (p = 0.003, p = 0.001, respectively), (Table 3). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.032, p = 0.013, respectively), (Table 3). The GST enzyme activity was significantly higher in Group DIR than the other three groups, however; CAT levels were similar among the groups (Table 3). Table 3: Oxidative state parameters in rat nephrotic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR DISCUSSION In this study, we have reported the protective effect of dexmedetomidine in experimental hepatic and renal IRI model in the rat by investigating the MDA and SOD levels biochemically. Besides, hepatic histopathological findings also supported our report. Ischemic damage may occur with trauma, hemorrhagic shock, and some surgical interventions, mainly hepatic and renal resections. Reperfusion following ischemia results in even more injury than ischemia itself. IRI is an inflammatory response accompanied by free radical formation, leucocyte migration and activation, sinusoidal endothelial cellular damage, deteoriated microcirculation and coagulation and complement system activation.1 We also detected injury in hepatic and renal tissue caused by reperfusion following ischemia in liver. Experimental and clinical evidence indicates that OS is involved in both the pathogenesis and the complications of diabetes mellitus.25,26 Diabetes mellitus is a serious risk factor for the development of renal and cardiovascular disease. It is also related to fatty changes in the liver.27 Diabetes-related organ damage seems to be the result of multiple mechanisms. Diabetes has been associated with increased free radical reactions and oxidant tissue damage in STZ-induced diabetic rats and also in patients.26Oxidative stress has been implicated in the destruction of pancreatic β-cells28 and could largely contribute to the oxidant tissue damage associated with chronic hyperglycemia.29 A number of reports have shown that antioxidants can attenuate the complications of diabetes in patients30 and in experimental models.28,31 This study demonstrated that diabetes causes a tendency to increase the IRI. There is a lot of investigations related to the pharmacological agents or food supplements applied for decreasing OS and IRI. Antioxidant agents paly an important role in IRI by effecting antioxidant system or lessening the formation of ROS. It has been reported that anesthetic agents too, are effective in oxidative stress.1 During surgical interventions, it seems rational to get benefit from anesthetic agents in prevention of OS caused by IRI instead of using other agents. It has been declared that; dexmedetomidine; as an α-2 agonist with sedative, hypnotic properties; is important in prevention of renal, focal, cerebral, cardiac, testicular and tourniquet-induced IRI.13-18 On the other hand Bostankolu et al. concluded that dexmedetomidine did not have an additional protective role for tournique induced IRI during routine general anesthesia.32 In this study; we have shown that dexmedetomidine has a reducing effect in IRI in diabetic rats. Some biochemical tests and histopathological evaluations are applied for bringing up oxidative stress and IRI in the tissues. Reactive oxygen species (ROS) that appear with reperfusion injury damage cellular structures through the process of the lipid peroxidation of cellular membranes and yield toxic metabolites such as MDA.33 As an important intermidiate product in lipid peroxidation, MDA is used as a sensitive marker of IRI.34 ROS-induced tissue injury is triggered by various defense mechanisms.35 The first defence mechanisms include the antioxidant enzymes of SOD, CAT, and GPx. These endogenous antioxidants are the first lines of defence against oxidative stres and act by scavenging potentially damaging free radical moieties.36 There is a balance between ROS and the scavenging capacity of antioxidant enzymes.1-8 In this study, for evaluation of oxidative damage and antioxidant activity, MDS, SOD, GST and CAT levels were determined in liver and kidney tissues. MDA levels in hepatic and renal tissues were higher in Group DIR compared to Group C and Group DIRD. GST levels were higher in Group DIR compared to all the other three groups. When the groups were arranged from highest to lowest order, with respect to CAT levels, the order was; Group DIR, Group DIRD, Group DC and Group C. However, the difference was not significant. The acute phase reactant MDA, as a marker of OS, was found to be high in Group DIR and low in Group DIRD. This could be interpreted as the presence of protective effect of dexmedetomidine in IRI. IRI developing in splanchnic area causes injury also in the other organs.35 Leithead et al showed that clinically significant hepatic IRI demonstrates a strong relationship with peri-operative acute kidney injury.2 In our experimental research that showed correlation to that of research by Leithead et al. After hepatic IRI in diabetic rats renal OS marker MDA levels were significantly more in Group DIR than Group DIRD. In our study, we observed histopathological changes in the ischemic liver tissue and alterations in the level of MDA, SOD, GST and CAT levels which are OS markers. Histopathological changes of the liver tissues are hepatocyt degeneration, sinusoidal dilatation, nuclear picnosis, celluler necrosis, mononuclear cell infiltrationat paranchimal tissue. These histopathological injury scores were significantly lower in the Group DIRD than those in group DIR. LIMITATION Study limitation is there was no negative control group, as this type of surgical intervention is not possible in rats without anesthesia. CONCLUSION The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease ischemia-reperfusion injury. Conflict of interest and funding: The authors have not received any funding or benefits from industry or elsewhere to conduct this study. 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Avec l'émergence d'applications millimétriques telles que le radar automobile ou le WHDMI, la fiabilité est devenue un enjeu extrêmement important pour l'industrie. Dans un émetteur/récepteur radio, les problèmes de fiabilité concernent principalement les transistors MOS intégrés dans les amplificateurs de puissance, compte-tenu des niveaux relativement élevés des puissances. Ces composants sont susceptibles de se détériorer fortement par le phénomène de l'injection de porteurs chauds impactant lourdement les performances des amplificateurs. Ce travail de thèse concerne la conception et l'étude de la fiabilité des amplificateurs de puissance fonctionnant aux fréquences millimétriques en technologies CMOS avancées. Le mémoire est articulé autour de quatre chapitres. Les deux premiers chapitres concernent l'étude, la conception, la modélisation et la caractérisation des éléments actifs et passifs intégrés sur silicium et utilisés pour réaliser des amplificateurs de puissance aux fréquences millimétriques. Le troisième chapitre décrit les trois amplificateurs de puissance conçus et réalisés pour les tests de fiabilité. Enfin, le dernier chapitre propose une étude complète de la fiabilité de ces circuits jusqu'au calcul de leur temps de vie
With the emergence of millimeter-wave applications such as automotive radar or WHDMI, the reliability became a very important issue for the industry. In a radio transceiver, the main reliability problems concern the MOS transistors used in the power amplifiers, due to the high power level. These devices are subject to deterioration by the hot carrier phenomenon. This impacts heavily the power amplifiers performances. This thesis work concerns the design and the study of the reliability of millimeter-wave power amplifiers in advanced CMOS technologies. The manuscript is divided into four chapters. The two first one concern the study, the design, the modeling and the characterization of integrated active and passive elements on silicon and used into power amplifiers at millimeter wave frequencies. The third chapter describes the three power amplifiers designed and realized for reliability tests. The final chapter provides a comprehensive study of the reliability of these circuits to calculate their lifetime

Avec l'émergence d'applications millimétriques telles que le radar automobile ou le WHDMI, la fiabilité est devenue un enjeu extrêmement important pour l'industrie. Dans un émetteur/récepteur radio, les problèmes de fiabilité concernent principalement les transistors MOS intégrés dans les amplificateurs de puissance, compte-tenu des niveaux relativement élevé des puissances. Ces composants sont susceptibles de se détériorer fortement par le phénomène de l'injection de porteurs chauds impactant lourdement les performances des amplificateurs. Ce travail de thèse concerne la conception et l'étude de la fiabilité des amplificateurs de puissance fonctionnant aux fréquences millimétriques en technologies CMOS avancées. Le mémoire est articulé autour de quatre chapitres. Les deux premiers chapitres concernent l'étude, la conception, la modélisation et la caractérisation des éléments actifs et passifs intégrés sur silicium et utilisés pour réaliser des amplificateurs de puissance aux fréquences millimétriques. Le troisième chapitre décrit les trois amplificateurs de puissance conçus et réalisés pour les tests de fiabilité. Enfin, le dernier chapitre propose une étude complète de la fiabilité de ces circuits jusqu'au calcul de leur temps de vie.

L'intégration du siliciure de nickel allié à un faible pourcentage de platine dans un environnement de transistors CMOS génère des difficultés à contrôler sa formation. Ces problèmes peuvent se traduire par une migration anormale du nickel court-circuitant le transistor, impactant les rendements de fabrication. L'objectif de cette thèse est d'améliorer la compréhension de ce phénomène physique apparaissant de manière aléatoire à l'échelle d'un circuit intégré pour la microélectronique avancée. L'étude de ce phénomène rare a été conduite à l'aide de méthodes de caractérisation locales aux limites des possibilités techniques actuelles : détection des fuites par contraste de tension, SIMS, Microscopie électronique et sonde atomique tomographique. L'ensemble des résultats statistiques et des caractérisations réalisées ont permis de proposer un scénario de formation des défauts du siliciure en fonction des conditions de sa formation et de la redistribution des éléments chimiques en présence.