Literatura académica sobre el tema "Triiodthyronin"

The aim of this study was to compare hormonal, anthropometric and metabolic parameters in men of the komi ethnic group with (n=23, BMI ≥25 kg/м2) or without (n=39, 18.4≤BMI 25 kg/м2) obesity. Totally 62 males living in Komi Republic were included in the study. It has been established that obesity was accompanied by an increase in serum concentrations of cholesterol and low density lipoprotein cholesterol in comparison with control group indicating metabolic disturbance. The data shows the significant effect of BMI on testosterone and FSH serum concentration, but not on LH, estradiol, thyrotrophic hormone, thyroxin and triiodthyronin levels. Overweight and obese men had lower circulating testosterone and higher FSH level in comparison with the controls. The reproductive hormone changes in overweight and obese men can result in deleterious effects on sexual functions including erectile dysfunction, reduced libido and alteration in spermatogenesis

Die subklinische Schilddrüsendysfunktion kann definiert werden als biochemisches Syndrom mit pathologischer Serumkonzentration des Thyrotropin (TSH) bei asymptomatischem Patienten mit normalen peripheren Schilddrüsenhormonwerten. Bei der subklinischen Hypothyreose ist das TSH erhöht bei normalen Werten für Thyroxin (T4) und Triiodthyronin (T3). Die Prävalenz dieser Schilddrüsenfunktionsstörung beträgt bei Frauen 7–8%, bei Männern etwa 3% und wird am häufigsten bei über 50jährigen Frauen beobachtet. Bei TSH-Werten > 12 mU/l (und positiven antithyreoidalen Antikörpern) ist das Risiko für die Entwicklung einer manifesten Hypothyreose am größten. Deshalb besteht in diesen Fällen eine absolute Indikation für die Behandlung mit L-Thyroxin. Bei TSH-Werten < 12 mU/l richtet sich die Therapieindikation nach Ätiologie, Risikofaktoren und eventuellen Begleitkrankheiten (z.B. Strumektomie, koronare Herzkrankheit, Depression, Infertilität). Die subklinische Hyperthyreose ist eine meist asymptomatische Schilddrüsenfunktionsstörung mit supprimiertem TSH bei normalen fT4- und fT3-Werten. Am häufigsten ist sie durch eine exogene Behandlung mit L-Thyroxin bedingt. Die endogene subklinische Hyperthyreose kommt bei Knotenstruma mit einer Prävalenz von bis zu 20% vor. Bei der subklinischen Hyperthyreose besteht ein erhöhtes Risiko für Vorhofflimmern und bei postmenopausalen Frauen für eine verminderte Knochendichte. Eine Behandlung ist allerdings nicht immer notwendig, aber eine Nachkontrolle ist obligat. Bei der endogenen Form der subklinischen Hyperthyreose mit Vorhofflimmern ohne andere Ursache muß eine Therapie mit Thyreostatika, Betablocker oder mit Radiojod eingesetzt werden. Bei der iatrogenen Form ist eine Dosisreduktion der T4-Therapie angezeigt. Es soll nach Möglichkeit ein knapp meßbares und/oder durch TRH minimal stimulierbares TSH erreicht werden.

Objective:Study concentrations of steroid and thyreoid hormones in patients with neurotic, stress-related and somatoform disorders.Methods:35 patients with dissociative (conversion) disorders (ISD-10, F44), 29 patients with adjustment disorders (ISD-10, F43.2) and mentally healthy persons (27 persons) were investigated. Immunofermantal analysis for definition of concentration of steroid and thyreoid hormones were carried out.Results:We have observed statistically significant increased level of cortizol (p< 0,05) in patients with adjustment disorders (635,04±48,69 nmol/l) in comparison with control and patients with dissociative (conversion) disorders (444,97±24,53 nmol/l and 443,13±23,00 nmol/l accordingly). The statistically significant the lowered maintenance of dehydroepiandrosteronum is characteristic for patients with adjustment disorders in comparison with control and patients of another group (3,9±0,26; 6,35±0,62 and 6,69±0,50 mkmol/l accordingly, p< 0,05). For patients with dissociative (conversion) disorders is characteristic the statistically significant increased level of triiodthyronin (1,71±0,12 nmol/l), in patients with adjustment disorders and mentally healthy persons this metric composed 1,26±0,02 nmol/l and 1,34±0,04 nmol/l accordingly. The level of thyroxin for the persons with dissociative (conversion) disorders differ from values of control and patients with adjustment disorders (23,68±2,07 pkmol/l; 17,64±1,43 pkmol/l and 14,69±0,53 pkmol/l accordingly, p< 0,05).Conclusion:For patients with adjustment disorders is characteristic the statistically significant increased level of cortizol and the lowered maintenance of dehydroepiandrosteronum. Dissociative (conversion) disorders are formed in conditions of the raised maintenance thyreoid hormones and the physiological maintenance of steroid hormones.The investigation supported by project of RHSF №06-06-00691а, №07-06-95673и/М and №08-06-00284а.

The triiodthyronine (T3), thyroxine (T4), glucose, free fatty acids (FFA), triacylglycerols (TAG) and total cholesterol concentrations were estimated in the blood serum and content of lipids in the liver in healthy (n=10) and ketotic (n=10) dairy cows in the post parturient period. Samples of liver and blood tissues were taken from all the cows. Pathohistoligical examination of liver tissues showed statistically significant higher (p<0.01) lipid infiltration in ketotic cows compared to healthy ones. Biochemical examination of blood serum showed significantly higher values (p<0.01) of free fatty acids in ketotic cows such as significantly lower concentrations of glucose (p<0.01), triacylglycerols (p<0.01), total cholesterol (p<0.05), triiodthyronine (p<0.05) and thyroxine (p<0.05) compared to values of these parameters in the blood serum in healthy cows. Significant increase of concentration of free fatty acids, such as positive correlation (r=0.51; p<0.05) between the free fatty acids in blood and the content of lipids in liver in ketotic cows compared to healthy ones, as well as pathohistological report, shows that during intensive lipomobilisation newly synthesized triacylglycerols accumulated in the hepatocytes. In ketotic cows hypo thyroidal status is established and it can be a significant factor in the development of fatty liver. .

Endocrine disruptors are exogenous substances that exhibit hormone-like action and consequently disrupt homeostatic action of endogenous hormones. DDT is the most common disruptor. The objective was to evaluate changes in thyroid hormone secretion after long-term exposure to low doses of DDT. The experiment was performed on male Wistar rats. The rats were given DDT at doses of 1.89±0.86 мg/kg/day and 7.77±0.17 мg/kg/day for 6 and 10 weeks. Dose dependent increase of serum total thyroxine, total triiodthyronine, and thyroid peroxidase was revealed after 6 weeks exposure. After 10 weeks free thyroxine secretion was reduced. Such alterations of the thyroid status are typical for iodine deficient goiter. The data obtained indicate that the main mechanism of DDT action includes disruption of thyroxine secretion by thyrocytes, but not inhibition of deiodinase activity and decrease of blood thyroid binding proteins.

AbstractBackgroundThe thyroid gland of patients with congenital heart disease may be exposed to large doses of iodine from various sources. We assessed the thyroid response after iodine exposure during conventional angiography in cardiac catheterization and angiographic computer tomography in childhood.MethodsRetrospective mid- to long-term follow-up of 104 individuals (24% neonates, 51% infants, 25% children) with a median age and body weight of 104 days [0–8 years] and 5.3 kg [1.6–20]. Serum levels of thyroid-stimulating hormone, free triiodthyronine and free thyroxine were evaluated at baseline and after excess iodine. We also assessed risk factors that may affect thyroid dysfunction.ResultsBaseline thyroidal levels were within normal range in all patients. The mean cumulative iodinate contrast load was 6.6 ± 1.6 mL/kg. In fact, 75% had experienced more than one event involving iodine exposure, whose median frequency was three times per patient [1–12]. During the median three years follow-up period [0.5–10], the incidence of thyroid dysfunction was 15.4% (n=16). Those patients developed acquired hypothyroidism (transient n=14, long-lasting n=2 [both died]) with 10 of them requiring temporary replacement therapy for transient thyroid dysfunction, while four patients recovered spontaneously. 88 individuals (84.6%) remained euthyroid. Repeated cardiac interventions, use of drugs that interfere with the thyroid and treatment in the intensive care unit at the index date were strong predictors for acquired thyroid dysfunction.ConclusionsThe incidence of acquired hypothyroidism after iodine excess was 15.4%. However, most patients developed only transient hypothyroidism. Systemic iodine exposure seems to be clinically and metabolically well tolerated during long-term follow-up.

The aim of the present investigation was to determine the correlation in the blood concentrations of thyroid hormones, lipids and glucose as well as the content of lipids in the liver of dairy cows in the transitional period. The animals (n = 40) were divided into four groups: the first group included late pregnant cows (n = 10) from the 10th to 4th day before calving; the second group included late pregnant cows (n = 10) from the 4th to 1st day before calving; the third group included clinically puerperal healthy cows (n = 10), whereas the fourth group included puerperal cows with clinical symptoms of ketosis (n = 10). Samples of liver and blood tissues were taken from all cows. Pathohistological examination of liver samples showed statistically significantly higher (p < 0.01) lipid infiltration in ketotic cows compared to healthy cows in late pregnancy and puerperium. Biochemical examination of blood serum showed significantly higher values (p < 0.01) of free fatty acids in ketotic cows, such as significantly lower blood concentrations of glucose (p < 0.01), triacylglycerols (p < 0.01), total cholesterol (p < 0.05), triiodthyronine (p < 0.05) and thyroxine (p < 0.05), compared to the values obtained in the blood serum in the groups of healthy cows before and after calving. In this study, significantly positive correlations were determined between the content of lipids in the liver and blood concentration of free fatty acids (r = 0.51; p < 0.05) as well as the negative ones between the content of lipids in the liver and blood concentrations of glucose (r = -0.69; p < 0.05), triacylglycerols (r = -0.55; p < 0.05) and total cholesterol (r = -0.50; p < 0.05) in the group of ketotic cows. Our investigations suggested that a hypothyroidal status was established in ketotic cows and that the blood concentrations of free fatty acids, triacylglycerols, total cholesterol and glucose served as major biochemical indicators in determining liver steatosis in the dairy cows in the transitional period.

AbstractWe conducted a study in a metropolitan area to establish regional reference intervals for thyreotropin (TSH) and the thyroid hormones free triiodthyronine (fT3) and free thyroxine (fT4). This was due to the different reference ranges, based on varying regional trials, presented for a widely used electrochemiluminescence immunoassay system.We investigated 292 apparently healthy adult subjects and excluded those with known history of thyroid disease, abnormal findings in the ultrasonographic examination of the thyroid gland, or elevated thyroid autoantibodies in serum. Accordingly, 204 of 292 subjects were included as the reference collective. We measured serum concentrations of TSH, fT3, and fT4 using the Elecsys assays from Roche Diagnostics and calculated the 2.5th and 97.5th percentiles.The nonparametrically calculated reference values for TSH and fT4 were 0.58–3.49 mIU/L and 11.58–20.46 pmol/L, respectively. Statistically remarkable is the finding of a normal Gaussian distribution of the fT3 serum concentration, leading to the parametric reference interval of 3.56–5.88 pmol/L.The established reference values for this regional collective showed tighter intervals than the reference ranges provided by the manufacturer. A carefully selected study population, based on the correspondent National Academy of Clinical Biochemistry criteria, ensured a valid set of reference ranges for TSH, fT3, and fT4, providing a basis for accurate in vitro thyroid testing. The 2.5th percentile for the fT3 is now in better accordance with clinical findings.

Abstract Background Melatonin, an important neurohormone released from the pineal gland, is generally accepted to exercise an inhibitor effect on the thyroid gland. Zinc mediates the effects of many hormones and is found in the structure of numerous hormone receptors. Aim The present study aims to examine the effect of melatonin supplementation and pinealectomy on leptin, neuropeptide Y (NPY), melatonin and zinc levels in rats with hypothyroidism and hyperthyroidism. Methods This study was performed on the 70 male rats. Experimental animals in the study were grouped as follows: control (C); hypothyroidism (PTU); hypothyroidism + melatonin (PTU + M); hypothyroidism + pinealectomy (PTU + Pnx); hyperthyroidism (H); hyperthyroidism + melatonin (H + M) and hyperthyroidism + pinealectomy (H + Pnx). Blood samples collected at the end of 4-week procedures were analyzed to determine melatonin, leptin, NPY and zinc levels. Results It was found that thyroid parameters thyroid stimulating hormone (TSH), free triiodthyronine (FT3), free thyroxine (FT4), total T3 (TT3) and total T4 (TT4) decreased in hypothyroidism groups and increased in the groups with hyperthyroidism. The changes in these hormones remained unaffected by melatonin supplementation and pinealectomy. Melatonin levels rose in hyperthyroidism and fell in hypothyroidism. Leptin and NPY levels increased in both hypothyroidism and hyperthyroidism. Zinc levels, on the other hand, decreased in hypothyroidism and pinealectomy, but increased in hyperthyroidism. Conclusion The results of the study demonstrate that hypothyroidism and hyperthyroidism affect leptin, NPY, melatonin and zinc values in different ways in rats. However, melatonin supplementation and pinealectomy do not have any significant influence on the changes occurring in leptin, NPY and zinc levels in thyroid dysfunction.

Ziel dieser Arbeit war die Entwicklung neuer Substanzen für die Gentherapie. Diese beinhaltet die Behebung von erblich bedingten Krankheiten wie z.B. Mucoviscidose. Dabei werden im Zellkern defekte Gene durch normale, gesunde DNA-Sequenzen ersetzt. Zur Einschleusung des Genmaterials in die Zellen (Transfektion) werden geeignete Transport-Systeme bzw. Methoden benötigt, die dort die Freisetzung der neu einzubauenden Gene (Genexpression ausgedrückt in Transfektionseffizienzen) gestatten. Hierfür wurden neue Polykation-DNA-Komplexe (Vektoren) auf Basis kationischer Polymere wie Poly(ethylenimin) (PEI) hergestellt, charakterisiert und nachfolgend in Transfektionsversuchen an verschiedenen Zelllinien eingesetzt.
Sowohl das kationische Ausgangspolymer PEI als auch das Pfropfcopolymer PEI-g-PEO (PEO-Seitenketten zur Erhöhung der Biokompatibilität) wurden mit Rezeptorliganden modifiziert, um eine verbesserte und spezifische Transfektion an ausgesuchten Zellen zu erreichen. Als Liganden wurden Folsäure (Transfektion an HeLa-Zellen), Triiod-L-thyronin (HepG2-Zellen) und die Uronsäuren der Galactose, Mannose, Glucose sowie die Lactobionsäure (HeLa-, HepG2- und 16HBE-Zellen) verwendet.
Das PEI, die Pfropfcopolymere PEI-g-PEO und die Ligand-funktionalisierten Copolymere wurden hinsichtlich ihrer chemischen Zusammensetzung und molekularen Parameter charakterisiert. Die Molmassenuntersuchungen mittels Größenausschlusschromatographie zeigten, dass nach der Synthese unterschiedliche Polymerfraktionen mit nicht einheitlicher chemischer Zusammensetzung vorlagen.
Die anschließenden Transfektionsversuche wurden mit Hilfe einer speziellen DNA (Luciferase) an den Zelllinien HepG2 (Leberkrebszellen), HeLa (Gebärmutterhalskrebszellen) und 16HBE (Atemwegsepithelzellen) durchgeführt. Die T3(Triiod-L-thyronin)-Vektoren zeigten in Abhängigkeit vom eingesetzten Komplexverhältnis Polykation/DNA ein Maximum in der Transfektion an HepG2-Zellen. Die Hypothese der rezeptorvermittelten Endozytose ließ sich durch entsprechende T3-Überschuss-Experimente und Fluoreszenzmikroskopie-Untersuchungen bestätigen. Dagegen konnte bei den Folsäure-Vektoren keine rezeptorvermittelte Endozytose beobachtet werden.
Bei den Vektoren mit Mannuronsäure-Ligand (Man) konnte an allen drei Zelllinien (HepG2, HeLa, 16HBE) eine konstante, hohe Transfereffizienz nachgewiesen werden. Sie waren bei allen eingesetzten Polymer-DNA-Verhältnissen effizienter als der Vergleichsvektor PEI. Dieses Transfektionsverhalten ließ sich durch Blockierung der Zuckerstruktur unterbinden. In Transfektionsexperimenten mit einem Überschuss an freier Mannuronsäure und fluoreszenzmikroskopischen Untersuchungen konnte eine rezeptorvermittelte Endozytose der Man-Vektoren an den o.g. Zelllinien nachgewiesen werden. Die anderen Uronsäure-Konjugate zeigten keine signifikanten Abweichungen im Transfektionsverhalten im Vergleich zum PEI-Vektor.
The goal of this work was the development of new non-viral gene transfer systems for the somatic gene therapy. For these non-viral gene vectors (polycation-DNA-complexes) on the base of ligand-functionalized polycations were synthesized, characterized and tested in transfection trials on different cell cultures (HepG2, HeLa, 16HBE).
In preliminary investigations PEI-g-PEO copolymers with different grafting densities of poly(ethylene oxide) PEO8 were synthesized and characterized. This was followed by modification of PEI and the copolymer PEI-g-PEO(20) with specific receptor ligands for transfection studies to the cell lines mentioned above. Folic acid (transfection at HeLa cells), triiodo-L-thyronine (HepG2 cells) and the uronic acids of galactose, mannose, glucose as well as the lactobionic acid (HeLa, HepG2 and 16HBE cells) were used as ligands. The coupling of the ligands was performed either without a spacer or via PEO side chains and was realized by carbodiimids.
The PEI and the grafted copolymers PEI-g-PEO as well as the ligand-functionalized copolymers were characterized regarding to their chemical composition and molecular parameters. Molar masses from sedimentation rate experiments of the AUC were obtained within the range of 35000 to 70000 g/mol. The molar mass investigations by means of SEC-MALLS revealed that after the grafting process both copolymers with heterogeneous chemical composition and unmodified PEI were present. The polydispersity of all PEI-g-PEO(20) based copolymers increased significantly compared with unmodified PEI. The molar masses increased with higher conversion degree as expected. The highly-substituted products exhibited an increasingly more compact structure in aqueous solution.
The following transfection studies were accomplished with the help of a luciferase reporter genes at the cultures HepG2 (liver cancer cells), HeLa (cervix cancer cells) and 16HBE (lung epithelium cells). The grafted copolymers PEI-g-PEO were compared to the unmodified PEI vector in transfection experiments. Here an almost identical transfer efficiency compared to the unmodified PEI vector could be maintained accompanied by reduced toxicity up to a PEO content of 17% w/w.
Folic acid copolymers were tested on HeLa cells in further vector studies. All folic acid vectors showed a maximum in the transfection at a N/P ratio (complex of polycation with DNA) of 2.5 and/or 5.0, which refers to a receptor-mediated endocytosis. However, no receptor-mediated endocytosis was observed in transfection.
A similar transfection behavior was observed with the T3 vectors on HepG2 cells dependent on the N/P ratio. The hypothetical receptor-mediated endocytosis could be confirmed within the T3-functionalized vectors by appropriate T3 excess experiments. Herein the transfer efficiency of the T3 gene vectors decreased significantly while adding free low-molecular weight triiodo-L-thyronine. In contrast to this the transfer efficiency of the unmodified PEI vector decreased only negligibly. A receptor-mediated endocytosis was also confirmed by fluorescence microscopy investigation of T3-functionalized aminodextranes at transfection of HepG2 cells. Subsequently, the T3 vectors were tested at mice in vivo. Here high transfer efficiencies in comparison to the unmodified PEI vector were determined particularly in the spleen as well as in the kidneys and thyroid. The T3 vectors should be suitable for a gene transfer into hepatocytes.
The vectors with uronic acid conjugates as ligands (galacturonic-, glucuronic and lactobionic acid) did not show significant deviations in the transfer efficiencies compared with the PEI vector. In contrast to this the vectors with mannuronic acid exhibit a constant high transfer efficiency at the three cell cultures HepG2, HeLa and 16HBE. They are more efficient than the PEI vector over the examined N/P range. Here the transfection proceeds independently of the charge of the complex (N/P ratio). This transfection behavior could be prevented by blocking the glycosidic OH groups of the Man vector. A receptor-mediated endocytosis of the Man vectors at the three examined cell lines (HepG2, HeLa, 16HBE) could be verified by means of transfection experiments with an excess of free mannuronic acid and fluorescence microscopic investigations.
In continuing studies new gene vectors on the base of cationic starch graft copolymers were synthesized and tested in transfection studies at HepG2 and 16HBE cells. Beyond that peptide-functionalized PEI vectors, which exhibit a nuclear localization sequence (TAT), were established and their transfection in vitro was determined. Compared to the PEI vector lower transfections of the vectors on the base of cationic starch graft copolymers was observed. However, an increase is expected by coupling with T3 and mannuronic acid ligands.

In the theoretical part of my thesis, I describe the thyroid, its importance, anatomy, creation of hormones and their regulation. There is also summarized the knowledge of external environment influences on the thyroid such as nutrition, climatic conditions or seasons and internal factors influences, mainly breed, efficiency and age. The practical part is focused on the evaluation of the thyroid activity of free-range ewes and lambs in the spring and autumn of 2013. The thesis also deals with the evaluation of possible relevance between the content of thyroid hormones in the blood serum and the physiological state of the sheep. Thanks to the correlation between TSH and thyroid hormones, the proper regulation of the thyroid of ewes and lambs was confirmed. The thyroid activity was higher in the spring than in the autumn. The hypothyroidism in the autumn was not proved because no referential values of TSH are set. In the autumn there was a lower level of glucose and cholesterol in the blood of the ewes determined which gives evidence of a lower energy income from the feed in the autumn. Also the urea level which is closely connected to the energy shortage, starvation, and high income of N substances in the feed dosage was in the autumn twice as high as in the spring. There was a positive correlation determined between the higher urea concentration and the higher thyroid activity. Owing to the change of the feed content, the TSH started to stimulate the thyroid to a higher thyroid hormones production and thus to its higher activity.