Journal articles: 'Patch de la membrane'

1

Garten, Matthias, Lars D. Mosgaard, Thomas Bornschlögl, Stéphane Dieudonné, Patricia Bassereau, and Gilman E. S. Toombes. "Whole-GUV patch-clamping." Proceedings of the National Academy of Sciences 114, no. 2 (December 21, 2016): 328–33. http://dx.doi.org/10.1073/pnas.1609142114.

Full text

Abstract:

Studying how the membrane modulates ion channel and transporter activity is challenging because cells actively regulate membrane properties, whereas existing in vitro systems have limitations, such as residual solvent and unphysiologically high membrane tension. Cell-sized giant unilamellar vesicles (GUVs) would be ideal for in vitro electrophysiology, but efforts to measure the membrane current of intact GUVs have been unsuccessful. In this work, two challenges for obtaining the “whole-GUV” patch-clamp configuration were identified and resolved. First, unless the patch pipette and GUV pressures are precisely matched in the GUV-attached configuration, breaking the patch membrane also ruptures the GUV. Second, GUVs shrink irreversibly because the membrane/glass adhesion creating the high-resistance seal (>1 GΩ) continuously pulls membrane into the pipette. In contrast, for cell-derived giant plasma membrane vesicles (GPMVs), breaking the patch membrane allows the GPMV contents to passivate the pipette surface, thereby dynamically blocking membrane spreading in the whole-GMPV mode. To mimic this dynamic passivation mechanism, beta-casein was encapsulated into GUVs, yielding a stable, high-resistance, whole-GUV configuration for a range of membrane compositions. Specific membrane capacitance measurements confirmed that the membranes were truly solvent-free and that membrane tension could be controlled over a physiological range. Finally, the potential for ion transport studies was tested using the model ion channel, gramicidin, and voltage-clamp fluorometry measurements were performed with a voltage-dependent fluorophore/quencher pair. Whole-GUV patch-clamping allows ion transport and other voltage-dependent processes to be studied while controlling membrane composition, tension, and shape.

APA, Harvard, Vancouver, ISO, and other styles

2

Sokabe, M., and F. Sachs. "The structure and dynamics of patch-clamped membranes: a study using differential interference contrast light microscopy." Journal of Cell Biology 111, no. 2 (August 1, 1990): 599–606. http://dx.doi.org/10.1083/jcb.111.2.599.

Full text

Abstract:

We have developed techniques for micromanipulation under high power video microscopy. We have used these to study the structure and motion of patch-clamped membranes when driven by pressure steps. Patch-clamped membranes do not consist of just a membrane, but rather a plug of membrane-covered cytoplasm. There are organelles and vesicles within the cytoplasm in the pipette tip of both cell-attached and excised patches. The cytoplasm is capable of active contraction normal to the plane of the membrane. With suction applied before seal formation, vesicles may be swept from the cell surface by shear stress generated from the flow of saline over the cell surface. In this case, patch recordings are made from membrane that was not originally present under the tip. The vesicles may break, or fuse and break, to form the gigasealed patch. Patch membranes adhere strongly to the wall of the pipette so that at zero transmural pressure the membranes tend to be normal to the wall. With transmural pressure gradients, the membranes generally become spherical; the radius of curvature decreasing with increasing pressure. Some patches have nonuniform curvature demonstrating that forces normal to the membrane may be significant. Membranes often do not respond quickly to changes in pipette pressure, probably because viscoelastic cytoplasm reduces the rate of flow through the tip of the pipette. Inside-out patches may be peeled from the walls of the pipette, and even everted (with positive pressure), without losing the seal. This suggests that the gigaseal is a distributed property of the membrane-glass interface.

APA, Harvard, Vancouver, ISO, and other styles

3

McNeil, P. L., S. S. Vogel, K. Miyake, and M. Terasaki. "Patching plasma membrane disruptions with cytoplasmic membrane." Journal of Cell Science 113, no. 11 (June 1, 2000): 1891–902. http://dx.doi.org/10.1242/jcs.113.11.1891.

Full text

Abstract:

Vesicle-vesicle fusion initiated in cell cytoplasm by high Ca(2+) can rapidly erect large membrane boundaries. These might be used as a ‘patch’ for resealing plasma membrane disruptions. Three central predictions of this ‘patch’ hypothesis are here established in sea urchin eggs. First, we show that surface markers for plasma membrane protein and lipid are initially absent over disruption sites after resealing is complete. Second, we demonstrate that resealing capacity is strongly dependent upon local availability of fusion competent cytoplasmic organelles, specifically the reserve or yolk granule. Lastly, we demonstrate that the reserve granule is capable of rapid (t(1/2) <1 second), Ca(2+)-regulated (high threshold) fusion capable of erecting large (>1000 μm(2)), continuous membrane boundaries. Production of patch vesicles for resealing may proceed by an ‘emergency’ fusion mechanism distinct from that utilized for the much slower, highly regulated, cytosol-requiring organelle-organelle fusion events typical of constitutive membrane trafficking pathways.

APA, Harvard, Vancouver, ISO, and other styles

4

Tedeschi, Henry, Carmen A. Mannella, and Charles L. Bowman. "Patch clamping the outer mitochondrial membrane." Journal of Membrane Biology 97, no. 1 (February 1987): 21–29. http://dx.doi.org/10.1007/bf01869611.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Minami, Kunihiro, and Yoshihiro Iwao. "The Formulation Design of Transdermal β1–blocker Patch （“Bisono®Tape”）." membrane 41, no. 2 (2016): 87–92. http://dx.doi.org/10.5360/membrane.41.87.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Engbretson, B. G., K. W. Beyenbach, and L. C. Stoner. "The everted renal tubule: a methodology for direct assessment of apical membrane function." American Journal of Physiology-Renal Physiology 255, no. 6 (December 1, 1988): F1276—F1280. http://dx.doi.org/10.1152/ajprenal.1988.255.6.f1276.

Full text

Abstract:

A technique is described whereby it is possible to evert a 0.5- to 1.0-mm segment of an amphibian renal tubule and perfuse it in vitro. Consequently, the apical membranes of an intact nephron fragment are directly accessible for electrophysiological study. Viability of the cells of everted diluting segments taken from Ambystoma kidney was indicated by 1) failure of the cells to take up trypan blue and 2) the existence of an apical membrane voltage (average 66 mV, cell negative), which decreased predictably in the presence of either 5 mM barium or elevated potassium in the luminal bathing solution. The utility of the everted tubule to patch clamp studies was tested. A large conductance channel that appeared to be selective for potassium could be demonstrated in a cell-attached patch of the apical membrane of an everted initial collecting tubule. The everted tubule preparation not only provides large quantities of apical membrane for patch clamp studies but, more importantly, allows the investigator to control the solutions bathing each membrane surface independently. The application of patch clamp techniques to perfused, everted tubules may then serve to more completely describe the role of the apical membrane in transcellular ion transport.

APA, Harvard, Vancouver, ISO, and other styles

7

Waqar, Tariq, Yasir Khan, and Muhammad Usman Riaz. "SUBAORTIC MEMBRANE;." Professional Medical Journal 24, no. 12 (November 29, 2017): 1801–5. http://dx.doi.org/10.29309/tpmj/2017.24.12.612.

Full text

Abstract:

Objectives: In this study, we presented our results regarding outcomes ofsurgical correction of sub-aortic membrane. Study Design: Retrospective observational study.Period: June 2012 to June 2017. Setting: CPEIC Multan, Pakistan. Methods: 51 patientsoperated for resection of sub aortic membrane. The resection of sub aortic membrane wasdone through the aorta. Evaluation of the aortic valve done in all patients. The aortic valve waseither replaced or repaired in cases of severe aortic regurgitation. Associated lesions such asventricular septal defects (VSD’s) were repaired with a dacron patch through the right atriumwhile ASD’s were repaired with a pericardial patch. Post-operative echocardiography was donebefore discharge and post-op LVOT gradients and aortic insufficiency were recorded for allthe patients. Results: There were 36 males and 15 females whose mean ages were 16.29years. On post-op echocardiography there was no residual significant LVOT gradient in anypatient. Three (3) patients developed mild to moderate aortic regurgitation post operativelybut none of them warrant any surgical intervention. There was only 1 death in the series whichwas due to VSD patch dehiscence. None of the patients developed conduction problems postoperatively needing any permanent pace maker. Mean pre-op LVOT gradient was 94.7 mmHgwhile it reduced to 20.7 post operatively (p-value <0.001). Conclusion: We concluded thatearly resection of sub aortic membrane can be safely accomplished with good results andsignificant drop in the mean LVOT pressure gradients post operatively.

APA, Harvard, Vancouver, ISO, and other styles

8

Hair, Philip I., Gillian M. Keating, and Kate McKeage. "Transdermal Matrix Fentanyl Membrane Patch (Matrifen®)." Drugs 68, no. 14 (2008): 2001–9. http://dx.doi.org/10.2165/00003495-200868140-00005.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Glover, Louise, and Robert H. Brown. "Dysferlin in Membrane Trafficking and Patch Repair." Traffic 8, no. 7 (June 5, 2007): 785–94. http://dx.doi.org/10.1111/j.1600-0854.2007.00573.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Ruknudin, A., M. J. Song, and F. Sachs. "The ultrastructure of patch-clamped membranes: a study using high voltage electron microscopy." Journal of Cell Biology 112, no. 1 (January 1, 1991): 125–34. http://dx.doi.org/10.1083/jcb.112.1.125.

Full text

Abstract:

We have developed techniques for studying patch-clamped membranes inside glass pipettes using high voltage electron microscopy (HVEM). To preserve the patch structure with the least possible distortion, we rapidly froze and freeze dried the pipette tip. The pipette is transparent for more than 50 microns from the tip. HVEM images of patches confirm light microscopy observations that the patch is not a bare bilayer, but a membrane-covered bleb of cytoplasm that may include organelles and cytoskeleton. The membrane that spans the pipette is commonly tens of micrometers from the tip of the pipette and occasionally as far as 100 microns. The structure of patches taken from a single cell type is variable but there are consistent differences between patches made from different cell types. With suction applied to the pipette before seal formation, we have seen in the light microscope vesicles swept from the plasmalemma up the pipette. These vesicles are visible in electron micrographs, particularly those made from chick cardiac muscle. Colloidal gold labeling of the patch permitted identification of lectin-binding sites and acetylcholine receptors. In young cultures of Xenopus myocytes, the receptors were diffuse. In 1-wk-old cultures, the receptors formed densely packed arrays. The patch pipette can serve, not only as a recording device, but as a tool for sampling discrete regions of the cell surface. Because the pipette has a constant path length for axial rotation, it is a unique specimen holder for microtomography. We have made preliminary tomographic reconstructions of a patch from Xenopus oocyte.

APA, Harvard, Vancouver, ISO, and other styles

11

Gordon, Sharona E., Eric N. Senning, Teresa K. Aman, and William N. Zagotta. "Transition metal ion FRET to measure short-range distances at the intracellular surface of the plasma membrane." Journal of General Physiology 147, no. 2 (January 11, 2016): 189–200. http://dx.doi.org/10.1085/jgp.201511530.

Full text

Abstract:

Biological membranes are complex assemblies of lipids and proteins that serve as platforms for cell signaling. We have developed a novel method for measuring the structure and dynamics of the membrane based on fluorescence resonance energy transfer (FRET). The method marries four technologies: (1) unroofing cells to isolate and access the cytoplasmic leaflet of the plasma membrane; (2) patch-clamp fluorometry (PCF) to measure currents and fluorescence simultaneously from a membrane patch; (3) a synthetic lipid with a metal-chelating head group to decorate the membrane with metal-binding sites; and (4) transition metal ion FRET (tmFRET) to measure short distances between a fluorescent probe and a transition metal ion on the membrane. We applied this method to measure the density and affinity of native and introduced metal-binding sites in the membrane. These experiments pave the way for measuring structural rearrangements of membrane proteins relative to the membrane.

APA, Harvard, Vancouver, ISO, and other styles

12

Pezeshkian, Weria, and John H. Ipsen. "Fluctuations and conformational stability of a membrane patch with curvature inducing inclusions." Soft Matter 15, no. 48 (2019): 9974–81. http://dx.doi.org/10.1039/c9sm01762c.

Full text

Abstract:

Membranes with curvature inducing inclusions display a range of cooperative phenomena, which can be linked to biomembrane function, e.g. membrane tubulation, vesiculation, softening and spontaneous tension.

APA, Harvard, Vancouver, ISO, and other styles

13

Su, Zhuocheng, Weihua Gao, Hongya Xu, Changan Xie, Qinglian Liu, and Lei Zhou. "Counting of Ion Channels on a Membrane Patch Aided by Patch-Clamp Fluorometry." Biophysical Journal 104, no. 2 (January 2013): 278a. http://dx.doi.org/10.1016/j.bpj.2012.11.1562.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Caporossi, Tomaso, Lorenzo De Angelis, Bianca Pacini, and Stanislao Rizzo. "Amniotic membrane for retinal detachment due to paravascular retinal breaks over patchy chorioretinal atrophy in pathologic myopia." European Journal of Ophthalmology 30, no. 2 (November 25, 2019): 392–95. http://dx.doi.org/10.1177/1120672119891415.

Full text

Abstract:

Purpose: To describe a new surgical technique, using a human amniotic membrane patch, in two cases of retinal detachment with paravascular retinal breaks over patchy chorioretinal atrophy in pathologic myopia, already underwent pars plana vitrectomy with the internal limiting membrane peeling for myopic foveoschisis. Methods: Surgical technique description with surgical video. A 23-gauge pars plana vitrectomy was performed. A human amniotic membrane patch was implanted under the neuroretina to seal the posterior retinal break. Standard silicone oil tamponade was performed at the end of the surgery. The patients were positioned face down after the operation for the first week. Optical coherence tomography scans were used in the follow-ups. Results: The 2 weeks postoperative optical coherence tomography showed a new tissue growth over the human amniotic membrane patch. The 3 months optical coherence tomography showed the new tissue entirely covering the human amniotic membrane plug. Visual acuity improved from 20/2000 (2 LogMAR) to 20/250 (1.1 LogMAR) 3 months after the operation in both patients. The silicone oil was extracted 2 months after surgery, and no recurrences were observed. The patient’s visual acuity remained stable at 20/250 after the silicone oil extraction. Conclusion: In these complex cases, human amniotic membrane transplantation can be a valid option, when internal limiting membrane has already been peeled in previous surgeries, to seal the posterior retinal breaks over high myopic chorioretinal atrophy, with encouraging results.

APA, Harvard, Vancouver, ISO, and other styles

15

S, Syahrijuita, Abdul Kadir, Sartini S, and Marhaen Hardjo. "Nata de coco patch miringoplasti pada ruptur membran timpani." Oto Rhino Laryngologica Indonesiana 48, no. 2 (January 30, 2019): 129. http://dx.doi.org/10.32637/orli.v48i2.276.

Full text

Abstract:

Latar belakang: Patch miringoplasti transkanal yang dapat dilakukan di Poli Klinik Telinga Hidung Tenggorok-Kepala Leher (THT-KL), saat ini merupakan pilihan yang didambakan bagi penatalaksanaan ruptur maupun perforasi membran timpani. Tindakan ini sederhana, praktis, tidak memerlukan alat, dan keterampilan khusus, dan dengan biaya yang murah. Membran yang terbuat dari air kelapa dengan bantuan Acetobacter xylinum yang dikenal dengan sebutan Patch Nata de Coco (PNC) memiliki karakteristik mirip kulit manusia yang elastis, biokompabilitas yang baik, non alergenik, dan dapat disterilkan tanpa merusak sifat fisiknya, direkomendasikan menjadi kandidat patch menggantikan patch kertas. Tujuan: Untuk menilai efek penggunaan PNC sebagai patch miringoplasti secara in vivo dan menilai efeknya terhadap waktu penutupan membran timpani (MT) ayam yang ruptur. Metode: Enam membran timpani ayam petelur dengan umur 72-96 minggu, berat badan 1500-2000 gram, telah dilakukan ruptur sejak 3 hari sebelumnya. Dipasangkan PNC transkanal pada 3 MT dan 3 lainnya dibiarkan tanpa perlakuan. Proses dan waktu penutupan didokumentasikan secara elektronik menggunakan otoskop digital. Hasil: Ruptur MT dengan pemasangan PNC 67% (2MT) menutup pada hari ke-4 dan 100% pada hari ke-5. Ruptur MT tanpa pemasangan PNC (kontrol) 33% (1MT) menutup pada hari ke-8 dan 100% pada hari ke-10. Waktu penutupan ruptur MT dengan pemasangan PNC lebih cepat 2x dibanding ruptur MT tanpa pemasangan PNC (kontrol). Kesimpulan: Patch nata de coco dapat digunakan sebagai patch miringoplasti dan dapat mempercepat penutupan ruptur membran timpani pada ayam. Background: The transcanal miringoplasty patch that can be performed at Ear Nose Throat–Head & Neck Clinic, is currently an ideal choice for the management of rupture and perforation of the tympanic membrane (TM). This procedure is simple, practical, does not require special tools and skill and low cost. The membrane which is made of coconut water processed with Acetobacter xylinum, is known as Nata de Coco Patch (NCP). It has characters of human skin elasticity, good biocompatibility, non-allergenic and can be sterilized without damaging its physical nature. PNC is recommended to be a candidate for replacing the paper patch. Purpose: To evaluate NCP usage in vivo on ruptured chicken TM and the closing time of ruptured TM. Method: Six TM of laying pullet aged 72-96 weeks and body weight 1500-2000 grams were ruptured 3 days previously. Transcanal NCP was installed at 3 perforations, and 3 others were left untreated. The process and TM closuring time was documented electronically using a digital otoscope. Results: Ruptured TM with NCP was closuring 67% (2 TM) on day 4, and total 100% had closured on the 5th day. Ruptured TM without NCP (control) was closuring 33% (1 TM) on day 8, and total 100% had closured on the 10th day. Ruptured TM with NCP closed twice faster than ruptured TM without NCP (control). Conclusion: Nata de coco patch (NCP) can be used as patch miringoplasty, and it accelerates the closure of the ruptured chicken tympanic membrane.

APA, Harvard, Vancouver, ISO, and other styles

16

Eyre, J. R. "Membrane action in isotropic patch-loaded unrestrained slabs." Magazine of Concrete Research 58, no. 6 (August 2006): 357–66. http://dx.doi.org/10.1680/macr.2006.58.6.357.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Seitz, Berthold, Sujata Das, Renate Sauer, Carmen Hofmann-Rummelt, Matthias W. Beckmann, and Friedrich E. Kruse. "Simultaneous Amniotic Membrane Patch in High-risk Keratoplasty." Cornea 30, no. 3 (March 2011): 269–72. http://dx.doi.org/10.1097/ico.0b013e3181eae8ea.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Miyoshi, Yuki, Azusa Saika, Takahiro Nagatake, Ayu Matsunaga, Jun Kunisawa, Yoshio Katakura, and Shino Yamasaki-Yashiki. "Mechanisms underlying enhanced IgA production in Peyer's patch cells by membrane vesicles derived from Lactobacillus sakei." Bioscience, Biotechnology, and Biochemistry 85, no. 6 (April 22, 2021): 1536–45. http://dx.doi.org/10.1093/bbb/zbab065.

Full text

Abstract:

ABSTRACT We analyzed the mechanisms underlying enhanced IgA production in the cells of Peyer's patch cells via membrane vesicles derived from Lactobacillus sakei subsp. sakei NBRC 15893. Depletion of CD11c+ cells from Peyer's patch cells suppressed the enhanced IgA production mediated by membrane vesicles. Meanwhile, the stimulation of bone-marrow–derived dendritic cells with membrane vesicles increased gene expression of inducible nitric oxide synthase, retinaldehyde dehydrogenase 2, and several inflammatory cytokines. The production of nitric oxide and interleukin (IL)-6 by membrane vesicle stimulation was induced via Toll-like receptor 2 on bone marrow–derived dendritic cells. Inhibition of inducible nitric oxide synthase and retinaldehyde dehydrogenase 2, as well as the neutralization of IL-6 in Peyer's patch cells, suppressed the enhanced IgA production by membrane vesicle stimulation. Hence, nitric oxide, retinoic acid, and IL-6 induced by membrane vesicles play crucial roles in the enhanced IgA production elicited by membrane vesicles in Peyer's patch cells.

APA, Harvard, Vancouver, ISO, and other styles

19

Sachs, F., and M. J. Song. "High-voltage electron microscopy of patch-clamped membranes." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 582–83. http://dx.doi.org/10.1017/s0424820100127402.

Full text

Abstract:

Cellular electrophysiology has been revolutionized by the introduction of patch clamp techniques. The patch clamp records current from a small patch of the cell membrane which has been sucked into a glass pipette. The membrane patch, a few micons in diameter, is attached to the glass by a seal which is electrically, diffusionally and mechanically tight. Because of the tight electrical seal, the noise level is low enough to record the activity of single ion channels over a time scale extending from 10μs to days. However, although the patch technique is over ten years old, the patch structure is unknown. The patch is inside a glass pipette where it has been impossible to see with standard electron microscopes. We show here that at 1 Mev the glass pipette is transparent and the membrane within can be seen with a resolution of about 30 A.

APA, Harvard, Vancouver, ISO, and other styles

20

Demuro, Angelo, and Ian Parker. "“Optical Patch-clamping”." Journal of General Physiology 126, no. 3 (August 15, 2005): 179–92. http://dx.doi.org/10.1085/jgp.200509331.

Full text

Abstract:

We describe an optical technique using total internal reflection fluorescence (TIRF) microscopy to obtain simultaneous and independent recordings from numerous ion channels via imaging of single-channel Ca2+ flux. Muscle nicotinic acetylcholine (ACh) receptors made up of αβγδ subunits were expressed in Xenopus oocytes, and single channel Ca2+ fluorescence transients (SCCaFTs) were imaged using a fast (500 fps) electron-multiplied c.c.d. camera with fluo-4 as the indicator. Consistent with their arising through openings of individual nicotinic channels, SCCaFTs were seen only when a nicotinic agonist was present in the bathing solution, were blocked by curare, and increased in frequency as roughly the second power of [ACh]. Their fluorescence amplitudes varied linearly with membrane potential and extrapolated to zero at about +60 mV. The rise and fall times of fluorescence were as fast as 2 ms, providing a kinetic resolution adequate to characterize channel gating kinetics; which showed mean open times of 7.9 and 15.8 ms when activated, respectively, by ACh or suberyldicholine. Simultaneous records were obtained from >400 channels in the imaging field, and we devised a novel “channel chip” representation to depict the resultant large dataset as a single image. The positions of SCCaFTs remained fixed (<100 nm displacement) over tens of seconds, indicating that the nicotinic receptor/channels are anchored in the oocyte membrane; and the spatial distribution of channels appeared random without evidence of clustering. Our results extend single-channel TIRFM imaging to ligand-gated channels that display only partial permeability to Ca2+, and demonstrate an order-of-magnitude improvement in kinetic resolution. We believe that functional single-channel imaging opens a new approach to ion channel study, having particular advantages over patch-clamp recording in that it is massively parallel, and provides high-resolution spatial information that is inaccessible by electrophysiological techniques.

APA, Harvard, Vancouver, ISO, and other styles

21

Krysik, Katarzyna, Dariusz Dobrowolski, Edward Wylegala, and Anita Lyssek-Boron. "Amniotic Membrane as a Main Component in Treatments Supporting Healing and Patch Grafts in Corneal Melting and Perforations." Journal of Ophthalmology 2020 (February 14, 2020): 1–7. http://dx.doi.org/10.1155/2020/4238919.

Full text

Abstract:

Purpose. To report on surgical approaches using amniotic membrane applications and patch grafts in corneal melting and perforations. Anatomical and functional results, including advantages and disadvantages of the interventions, will also be explored. Methods. A five-year retrospective analysis of 189 surgical treatments involving corneal melting with perforation was performed. In one evaluated treatment type, a graft of amniotic membrane, often folded one to three times, was sutured with the epithelial side facing the previously mechanically debrided corneal tissue. A larger monolayer amniotic patch was then sutured, with the epithelial side facing the top of the first membrane, to the perilimbal conjunctiva. For corneal patch grafts, the size-fitting technique of graft trephination was applied, and the donor-recipient junctions were sewn with interrupted sutures. All the procedures were evaluated, noting outcomes and complications of surgery, preoperative and postoperative visual acuities, postoperative intraocular pressures, graft rejection, and other late comorbidities and complications. Results. We performed 119 amniotic membrane applications (63%) and 70 corneal patch grafts (37%). Anatomical reconstruction of the anterior chamber was achieved in 157 eyes, of which 102 eyes (86%) received an amniotic membrane and 55 eyes (79%) were treated with the patch graft technique. In 63 eyes (33%), more than one amnion or graft treatment was necessary to close the corneal perforation. Conclusions. The success of medical and surgical management depends on the cause of corneal melting, and amniotic membrane applications often require further intervention; nevertheless, patch grafts deliver better tectonic reconstruction than amniotic membrane alone.

APA, Harvard, Vancouver, ISO, and other styles

22

Davenport, Nicholas R., Kevin J. Sonnemann, Kevin W. Eliceiri, and William M. Bement. "Membrane dynamics during cellular wound repair." Molecular Biology of the Cell 27, no. 14 (July 15, 2016): 2272–85. http://dx.doi.org/10.1091/mbc.e16-04-0223.

Full text

Abstract:

Cells rapidly reseal after damage, but how they do so is unknown. It has been hypothesized that resealing occurs due to formation of a patch derived from rapid fusion of intracellular compartments at the wound site. However, patching has never been directly visualized. Here we study membrane dynamics in wounded Xenopus laevis oocytes at high spatiotemporal resolution. Consistent with the patch hypothesis, we find that damage triggers rampant fusion of intracellular compartments, generating a barrier that limits influx of extracellular dextrans. Patch formation is accompanied by compound exocytosis, local accumulation and aggregation of vesicles, and rupture of compartments facing the external environment. Subcellular patterning is evident as annexin A1, dysferlin, diacylglycerol, active Rho, and active Cdc42 are recruited to compartments confined to different regions around the wound. We also find that a ring of elevated intracellular calcium overlaps the region where membrane dynamics are most evident and persists for several minutes. The results provide the first direct visualization of membrane patching during membrane repair, reveal novel features of the repair process, and show that a remarkable degree of spatial patterning accompanies damage-induced membrane dynamics.

APA, Harvard, Vancouver, ISO, and other styles

23

Wang, Tzu-Ming, and Donald W. Hilgemann. "Ca-dependent Nonsecretory Vesicle Fusion in a Secretory Cell." Journal of General Physiology 132, no. 1 (June 18, 2008): 51–65. http://dx.doi.org/10.1085/jgp.200709950.

Full text

Abstract:

We have compared Ca-dependent exocytosis in excised giant membrane patches and in whole-cell patch clamp with emphasis on the rat secretory cell line, RBL. Stable patches of 2–4 pF are easily excised from RBL cells after partially disrupting actin cytoskeleton with latrunculin A. Membrane fusion is triggered by switching the patch to a cytoplasmic solution containing 100–200 μM free Ca. Capacitance and amperometric recording show that large secretory granules (SGs) containing serotonin are mostly lost from patches. Small vesicles that are retained (non-SGs) do not release serotonin or other substances detected by amperometry, although their fusion is reduced by tetanus toxin light chain. Non-SG fusion is unaffected by N-ethylmaleimide, phosphatidylinositol-4,5-bis-phosphate (PI(4,5)P2) ligands, such as neomycin, a PI-transfer protein that can remove PI from membranes, the PI(3)-kinase inhibitor LY294002 and PI(4,5)P2, PI(3)P, and PI(4)P antibodies. In patch recordings, but not whole-cell recordings, fusion can be strongly reduced by ATP removal and by the nonspecific PI-kinase inhibitors wortmannin and adenosine. In whole-cell recording, non-SG fusion is strongly reduced by osmotically induced cell swelling, and subsequent recovery after shrinkage is then inhibited by wortmannin. Thus, membrane stretch that occurs during patch formation may be a major cause of differences between excised patch and whole-cell fusion responses. Regarding Ca sensors for non-SG fusion, fusion remains robust in synaptotagmin (Syt) VII−/− mouse embryonic fibroblasts (MEFs), as well as in PLCδ1, PLC δ1/δ4, and PLCγ1−/− MEFs. Thus, Syt VII and several PLCs are not required. Furthermore, the Ca dependence of non-SG fusion reflects a lower Ca affinity (KD ∼71 μM) than expected for these C2 domain–containing proteins. In summary, we find that non-SG membrane fusion behaves and is regulated substantially differently from SG fusion, and we have identified an ATP-dependent process that restores non-SG fusion capability after it is perturbed by membrane stretch or cell dilation.

APA, Harvard, Vancouver, ISO, and other styles

24

Coraboeuf, E., and D. Escande. "Ionic Currents in the Human Myocardium." Physiology 5, no. 1 (February 1, 1990): 28–31. http://dx.doi.org/10.1152/physiologyonline.1990.5.1.28.

Full text

Abstract:

Recent measurements by patch-clamp techniques of membrane currents from enzymatically isolated human cardiac cells have shown the existence in human atrial membranes of seven different types of ionic channels. Such studies open new perspectives for human cardiac pharmacology and physiopathology.

APA, Harvard, Vancouver, ISO, and other styles

25

Petersen, OH, and CCH Petersen. "The Patch-Clamp Technique: Recording Ionic Currents Through Single Pores in the Cell Membrane." Physiology 1, no. 1 (February 1, 1986): 5–8. http://dx.doi.org/10.1152/physiologyonline.1986.1.1.5.

Full text

Abstract:

When an intracellular electrode records an electrical event in the cell membrane, we know that there are changes in the membrane's permeability to various ions. These changes are mediated by membrane entities known as pores or ion channels. The advance of the patch-clamp technique, which permits the study of changes in individual ion channels, in the simplest case conforms to a simple open-close two-state model.

APA, Harvard, Vancouver, ISO, and other styles

26

Zhan, Xiaoping, Zhenmin Mao, Sijing Chen, Shaoxiong Chen, and Liqun Wang. "Formulation and evaluation of transdermal drug-delivery system of isosorbide dinitrate." Brazilian Journal of Pharmaceutical Sciences 51, no. 2 (June 2015): 373–82. http://dx.doi.org/10.1590/s1984-82502015000200015.

Full text

Abstract:

<p>The purpose of this study was to develop a reservoir-type transdermal delivery system for isosorbide dinitrate (ISDN). The developed patch consisted of five layers from bottom to top, namely, a temporary liner, an adhesive layer, a rate-controlling membrane, a reservoir and a backing. The effects of chemical penetration enhancers, reservoir materials and rate-controlling membranes on the release behaviour of ISDN from the transdermal patch were studied, and the<italic> in vitro</italic> release of ISDN from the developed patch was studied and compared with the commercially available ISDN patch. The results showed that there was no significant difference in permeation rates between the developed reservoir-type patch and the commercially available ISDN patch (<italic>p</italic>> 0.05). Moreover, the cumulative release ratio of the commercially available ISDN patch in 48 h was up to 89.8%, whereas the developed patch was only 34.9%, which meant the sustained release time of the developed patch was much longer than the commercially available ISDN patch, and would promote the satisfaction of the patient.</p>

APA, Harvard, Vancouver, ISO, and other styles

27

Kon, Tomohiko, Tomomi Honda, and Akira Sasaki. "Estimation of the Oxidative Deterioration of Turbine Oil Using Membrane Patch Color." Advances in Tribology 2020 (February 7, 2020): 1–8. http://dx.doi.org/10.1155/2020/1708408.

Full text

Abstract:

Lubricating oils degrade into two main products: oxidation products and solid particles. Oxidation products, called varnish, of turbine oils for power generation have become a particularly serious problem in recent years. The first step in determining the potential to produce varnish is to determine the remaining life of the antioxidant in the oil, but even though turbine oil may have antioxidants of sufficient longevity, varnish problems still occur frequently. Accordingly, to prevent varnish, it is necessary to diagnose oil oxidation products. Thus, the authors have developed a diagnostic method using membrane patch color, but the relationship between membrane patch color and the remaining life of turbine oils has yet to be clarified. This paper investigates a new method for estimating the oxidative degradation of turbine oils that uses membrane patch color and the dry turbine oxidation stability test (dry TOST) based on oxidation products and the remaining life of the turbine oils. Sample oils were prepared and degraded by oxidation in the laboratory using a dry TOST apparatus, and the membrane patch color was measured using a colorimetric patch analyzer (CPA). The relationship between membrane patch color and the rotating pressure vessel oxidation test (RPVOT) residual rate was then investigated. The results show that the new estimation method using the CPA and dry TOST is able to monitor the decrease of the RPVOT residual rate from the early stages of oxidative deterioration.

APA, Harvard, Vancouver, ISO, and other styles

28

Just, T., T. Zehlicke, O. Specht, W. Sass, C. Punke, W. Schmidt, E. Lankenau, D. Behrend, and H. W. Pau. "Detection of tympanic membrane movement using film patch with integrated strain gauge, assessed by optical coherence tomography: experimental study." Journal of Laryngology & Otology 125, no. 5 (January 27, 2011): 467–73. http://dx.doi.org/10.1017/s0022215110002859.

Full text

Abstract:

AbstractObjective:We report an ex vivo and in vivo experimental study of a device designed to measure tympanic membrane movement under normal and pathological conditions, assessed using optical coherence tomography.Materials and methods:We designed two types of flexible, round film patch with integrated strain gauge, to be attached to the tympanic membrane in order to measure tympanic membrane movement. Tympanic membrane attachment was assessed using optical coherence tomography. The devices were tested experimentally using an ex vivo model with varying middle-ear pressure.Results:Optical coherence tomography reliably assessed attachment of the film patch to the tympanic membrane, before and after middle-ear pressure changes. Strain gauge voltage changes were directly proportional to middle-ear pressure recordings, for low pressure changes. Tympanic membrane perforations smaller than 2 mm could be sealed off with the film patch.Conclusion:Attachment of the film patch with integrated strain gauge to the tympanic membrane was not ideal. Nevertheless, the strain gauge was able to precisely detect small pressure changes within the middle ear, in this experimental model.

APA, Harvard, Vancouver, ISO, and other styles

29

WATANABE, Shu-Ichi, and Motohiko MURAKAMI. "Phototransduction in Cones as Examined in Excised Membrane Patch." Japanese Journal of Physiology 42, no. 2 (1992): 309–20. http://dx.doi.org/10.2170/jjphysiol.42.309.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Kim, Jang Ho, Seong Jun Choi, Jung-Sub Park, Ki Taek Lim, Pill-Hoon Choung, Seung Won Kim, Jong Bin Lee, Jong Hoon Chung, and Yun-Hoon Choung. "Tympanic Membrane Regeneration Using a Water-Soluble Chitosan Patch." Tissue Engineering Part A 16, no. 1 (January 2010): 225–32. http://dx.doi.org/10.1089/ten.tea.2009.0476.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Kheirkhah, Ahmad. "Temporary Sutureless Amniotic Membrane Patch for Acute Alkaline Burns." Archives of Ophthalmology 126, no. 8 (August 11, 2008): 1059. http://dx.doi.org/10.1001/archopht.126.8.1059.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Tu, Elmer Y. "Descemet Membrane Endothelial Keratoplasty Patch for Persistent Corneal Hydrops." Cornea 36, no. 12 (December 2017): 1559–61. http://dx.doi.org/10.1097/ico.0000000000001351.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Franciolini, F. "Patch clamp technique and biophysical study of membrane channels." Experientia 42, no. 6 (June 1986): 589–94. http://dx.doi.org/10.1007/bf01955551.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Miyagi, Atsushi, Simon Scheuring, Beatrice Ramm, and Petra Schwille. "MinDE Membrane Patch Oscillations Observed by High-Speed AFM." Biophysical Journal 112, no. 3 (February 2017): 328a. http://dx.doi.org/10.1016/j.bpj.2016.11.1773.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Szabó, Ildikó, Valeria Petronilli, and Mario Zoratti. "A patch-clamp investigation of theStreptococcus faecalis cell membrane." Journal of Membrane Biology 131, no. 3 (February 1993): 203–18. http://dx.doi.org/10.1007/bf02260109.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Pontes, Kelly Cristine de Sousa, Andréa Pacheco Batista Borges, Renato Barros Eleotério, Emily Correna Carlo Reis, and Tatiana Schmitz Duarte. "Preserved xenogenic amniotic membrane as a patch on the repair of superficial corneal ulcers in rabbits." Revista Ceres 59, no. 3 (June 2012): 313–20. http://dx.doi.org/10.1590/s0034-737x2012000300004.

Full text

Abstract:

The aim of this study was to evaluate the effects of canine amniotic membrane, previously preserved in glycerin, used as a patch on the repair of experimentally-made superficial corneal ulcers and to compare corneal epithelization between the treated and non-treated groups. Xenogeneic amniotic membranes were collected aseptically and preserved in 99% glycerin at room temperature. Each animal was anesthetized and submitted to superficial corneal keratectomy of the left eye. The treated group received a fragment of canine amniotic membrane as a patch, while the control group had no treatment. The treated group showed blepharospasm, ocular discharge and conjunctival congestion. The membrane accelerated corneal repair in the beginning of the process, however, it delayed its conclusion (p<0.05). Treated eyes showed greater vessel formation and decreased corneal transparency (p<0.05). The stroma of the control group was thicker than that of the treated group (p<0.05). We suggest that amniotic membrane used in this manner can be applied as a therapy for superficial corneal ulcers in the beginning phases of the repair process.

APA, Harvard, Vancouver, ISO, and other styles

37

Zheng, Jie. "Patch Fluorometry: Shedding New Light on Ion Channels." Physiology 21, no. 1 (February 2006): 6–12. http://dx.doi.org/10.1152/physiol.00041.2005.

Full text

Abstract:

Patch fluorometry has emerged as a new approach to the study of the structure-function relationship in membrane-embedded functional ion channels. Simultaneous fluorescent and electrical recordings are achieved from a small number of channels in a cell-free membrane patch, yielding high recording sensitivities. Further improvement of this approach should permit direct observation of the gating motion of a single-channel protein.

APA, Harvard, Vancouver, ISO, and other styles

38

Taylor, C. W., and O. Dellis. "Plasma membrane IP3 receptors." Biochemical Society Transactions 34, no. 5 (October 1, 2006): 910–12. http://dx.doi.org/10.1042/bst0340910.

Full text

Abstract:

IP3Rs (inositol 1,4,5-trisphosphate receptors) are expressed in the membranes of non-mitochondrial organelles in most animal cells, but their presence and role within the plasma membrane are unclear. Whole-cell patch–clamp recording from DT40 cells expressing native or mutated IP3Rs has established that each cell expresses just two or three functional IP3Rs in its plasma membrane. Only approx. 50% of the Ca2+ entry evoked by stimulation of the B-cell receptor is mediated by store-operated Ca2+ entry, the remainder appears to be carried by the IP3Rs expressed in the plasma membrane. Ca2+ entering the cell via just two large-conductance IP3Rs is likely to have very different functional consequences from the comparable amount of Ca2+ that enters through the several thousand low-conductance store-operated channels.

APA, Harvard, Vancouver, ISO, and other styles

39

McCulloh, D. H., and E. L. Chambers. "A localized zone of increased conductance progresses over the surface of the sea urchin egg during fertilization." Journal of General Physiology 97, no. 3 (March 1, 1991): 579–604. http://dx.doi.org/10.1085/jgp.97.3.579.

Full text

Abstract:

Although activation of a sea urchin egg by sperm leads to three phases of membrane conductance increase in the egg, the mechanism by which the sperm causes these conductance changes is not known. We used the loose patch clamp technique to localize the conductance changes in voltage clamped eggs. A patch of the egg's membrane was isolated from the bath by pressing the loose patch clamp pipette against the egg surface. Sperm added to the bath attached to the surface of the egg in a region other than at the isolated membrane patch. During phase 1 of the activation current, no changes of the membrane conductance were detected. At the time of, and subsequent to the onset of phase 2, large currents recorded between the interior of the patch pipette and the bath were attributed to changes of the seal resistance between the surface of the egg and the pipette. A local change of membrane conductance was observed during phase 2 despite the changes of seal resistance. During phase 2, the large amplitude and short duration of the local membrane conductance increase relative to the membrane, conductance increase for the whole egg during phase 2 indicated that the conductance increase occurred over the entire surface of the egg, but not simultaneously. The time when the peak conductance for the membrane patch occurred, relative to the time of onset for phase 2 in the whole egg, depended on the distance, measured in a straight line, between the site of sperm attachment and the tip of the pipette. These data indicate that the localized conductance increase progressed over the surface of the egg from the site of sperm attachment to the opposite pole of the egg. It is proposed that the local conductance increase, the cortical reaction, and the change of seal resistance are all evoked by a common cytoplasmic message that progresses throughout the cytoplasm of the egg from the site of sperm attachment to the opposite pole of the egg.

APA, Harvard, Vancouver, ISO, and other styles

40

Maue, R. A., and V. E. Dionne. "Patch-clamp studies of isolated mouse olfactory receptor neurons." Journal of General Physiology 90, no. 1 (July 1, 1987): 95–125. http://dx.doi.org/10.1085/jgp.90.1.95.

Full text

Abstract:

Olfactory receptor neurons isolated from embryonic, neonatal, and adult mice were studied using the patch-clamp technique. Several distinct types of ion channels were characterized in patches of membrane from the neuronal soma and the dendritic knob of receptor neurons, including a 130-pS Ca++-activated K+ channel with voltage-dependent kinetics, an 80-pS Ca++-activated K+ channel with voltage-insensitive kinetics, a 25-pS K+ channel with properties similar to inward rectifiers, and a 40-pS K+ channel that was activated and then inactivated by rapid depolarization. Evidence of large-conductance (greater than 200 pS) Cl- channels, which were Ca++ insensitive and increasingly active at depolarizing membrane potentials, and voltage-activated Ca++ channels (16 pS) was also obtained. From K+ channel activity recorded from cell-attached patches, the intracellular [Ca++] was inferred to be below 0.1 microM, and the membrane potential was inferred to be approximately -50 mV. The receptor neurons had high input resistances, and action potentials could be elicited by picoampere amounts of depolarizing current. The receptor neurons responded to applied odorant molecules and to forskolin with increases in membrane conductance. These results provide a description of the membrane properties of olfactory receptor neurons and a basis for understanding their electrical activity and response to odorants.

APA, Harvard, Vancouver, ISO, and other styles

41

Ruknudin, A., M. J. Song, A. Auerbach, and F. Sachs. "The structure of patch-clamped membranes in high voltage Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 936–37. http://dx.doi.org/10.1017/s0424820100156663.

Full text

Abstract:

The study of single ion channel kinetics in cell electrophysiology has been made possible by the introduction of patch-clamp techniques. Recordings can be made from a patch of membrane either attached to the cell or excised into controlled solutions. Though this technique has been widely used for more than a decade, the structure of the membrane patch and its associated cytoplasmic elements are not known except for recent work done in this laboratory . We have improved this technique to visualize membrane patches using high voltage electron microscope and also identified one class of channels in the patch by immunocytochemistry.The procedure for preserving biological structure in a glass patch pipette is basically same as described earlier as “dry mounting technique” . Briefly, after making a patch, the pipette is removed from the bath and the tip is freeze-fixed in liquid propane. A slight negative pressure is applied to the pipette while freeze-fixing in order to stretch the shape of the patch. Once fixed, the tip is not exposed to temperatures higher than-126° C. A 0.5 cm bit of the pipette tip is broken off, stored in IN2, and then freeze dried between -126° to -80° C under high vaccum (10-6 Torr).

APA, Harvard, Vancouver, ISO, and other styles

42

Yoshita, Tsuyoshi, Akira Kobayashi, Kazuhisa Sugiyama, and Scheffer C. G. Tseng. "Oxygen permeability of amniotic membrane and actual tear oxygen tension beneath amniotic membrane patch." American Journal of Ophthalmology 138, no. 3 (September 2004): 486–87. http://dx.doi.org/10.1016/j.ajo.2004.03.021.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Wehner, F., L. Garretson, K. Dawson, Y. Segal, and L. Reuss. "A nonenzymatic preparation of epithelial basolateral membrane for patch clamp." American Journal of Physiology-Cell Physiology 258, no. 6 (June 1, 1990): C1159—C1164. http://dx.doi.org/10.1152/ajpcell.1990.258.6.c1159.

Full text

Abstract:

A preparation has been developed that permits patch clamping of the basolateral membrane of Necturus gallbladder epithelial cells with a high success rate. The epithelium is separated from the underlying tissues mechanically, without enzymatic treatment. Its apical surface is attached to a plastic cover slip, and the basolateral surface, facing up, is cleaned with a suction pipette under microscopic observation. With this cleaning procedure, the success rate in obtaining gigaohm seals increases from less than 1% to approximately 10% of the attempts. The cells appear to retain their structural and functional integrity, as evidenced by electron-microscopic appearance and magnitude of cell membrane voltages. Major advantages of the preparation are that the basolateral membrane domain is preserved and that enzymatic treatment, which could potentially alter membrane proteins, is not necessary.

APA, Harvard, Vancouver, ISO, and other styles

44

Kim, Jin, Chun Hoi Kim, Chan Hum Park, Jae-Nam Seo, HaeYong Kweon, Seok Woo Kang, and Kwang Gill Lee. "Comparison of methods for the repair of acute tympanic membrane perforations: Silk patch vs. paper patch." Wound Repair and Regeneration 18, no. 1 (January 2010): 132–38. http://dx.doi.org/10.1111/j.1524-475x.2009.00565.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Kawaguchi, Y., C. J. Wilson, and P. C. Emson. "Intracellular recording of identified neostriatal patch and matrix spiny cells in a slice preparation preserving cortical inputs." Journal of Neurophysiology 62, no. 5 (November 1, 1989): 1052–68. http://dx.doi.org/10.1152/jn.1989.62.5.1052.

Full text

Abstract:

1. The morphology, electrical membrane properties, and corticostriatal excitatory postsynaptic potentials (EPSPs) of two groups of neostriatal projection cells, patch cells, and matrix spiny cells were compared in the rat by the use of an in vitro slice preparation that preserves inputs from medial agranular cortex. Spiny cells were stained intracellularly with biocytin and identified as belonging to the patch (striosomal) compartment or to the matrix by immunohistochemistry for the 28 kD calcium-binding protein calbindin on the same sections. 2. Patch and matrix neurons had very similar axonal and dendritic morphology. Both patch and matrix cells extended their dendrites and local axon collaterals almost exclusively in their respective compartments. Patch cells and most matrix cells had local axon collaterals within or near the parent dendritic domain. However there was a class of matrix cells that extended axon collaterals over a much wider portion of the neostriatum but still restricted to the matrix compartment. 3. Input resistance and membrane time constant were estimated from the membrane response to intracellularly applied current pulses. The average values of matrix cells were and 8.41 ms. The values of patch cells were 31.8 M omega and 8.19 ms and were within the range of those of matrix cells. Both types of cells showed the same kinds of membrane nonlinearities when tested with the use of current pulses. Input resistance and time constant were both strongly affected by a fast anomalous rectification and were thus voltage-dependent, decreasing with membrane polarization. Slow ramplike depolarizing responses were observed in response to depolarizing current steps. 4. Repetitive firing was examined with the use of depolarizing current pulses. In both types of spiny cells, trains of action potentials showed little adaptation of spike frequency and linearly increased with current intensities less than 1 nA. The slopes frequency, calculated from the first and second intervals, were 115.0 and 107.2 Hz/nA, respectively, for matrix cells and 86.0 and 82.8 Hz/nA for patch cells. 5. Stimulation of the medial agranular cortex induced EPSPs in some striatal cells in both compartments. EPSP in matrix cells often showed both short-latency and long-latency components, corresponding to two early components of the response observed in vivo. Some matrix cells, and all patch cells, showed only the longer latency EPSP component. The average latency was 6.3 ms in matrix cells and 9.1 ms in patch cells. The relationship between EPSP amplitude and membrane potential was nonlinear, with EPSP amplitude and duration increasing with decreasing membrane polarization.(ABSTRACT TRUNCATED AT 400 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

46

Zhao, Y., S. Inayat, D. A. Dikin, J. H. Singer, R. S. Ruoff, and J. B. Troy. "Patch clamp technique: Review of the current state of the art and potential contributions from nanoengineering." Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanoengineering and Nanosystems 222, no. 1 (March 1, 2008): 1–11. http://dx.doi.org/10.1243/17403499jnn149.

Full text

Abstract:

The patch clamp technique permits high-resolution recording of the ionic currents flowing through a cell's plasma membrane. In different configurations, this technique has allowed experimenters to record and manipulate the currents that flow either through single ion channels or those that flow across the whole plasma membrane. Unfortunately, the conventional patch clamp method is laborious, requiring the careful fabrication of electrodes, skillful manipulation of the patch pipette towards a cell, and the clever design of electronics and apparatus to allow low-noise recordings. Advances in microfabrication offer promising technologies for high-throughput patch clamp recordings, particularly suitable for drug screening. This paper provides a review of the advances that have been made in the patch clamp technique over the years and considers where application of nanotechnology might provide significant contributions in the future.

APA, Harvard, Vancouver, ISO, and other styles

47

Jeon, Hyeon Seop, Jeong Hwa Kim, Martin B. G. Jun, and Young Hun Jeong. "Fabrication of Thermochromic Membrane and Its Characteristics for Fever Detection." Materials 14, no. 13 (June 22, 2021): 3460. http://dx.doi.org/10.3390/ma14133460.

Full text

Abstract:

Body temperature is an important indicator of the health status of the human body. Thus, numerous studies have been conducted in various fields to measure body temperature. In this study, a biocompatible thermochromic membrane that changes its color when the temperature becomes higher than the transition temperature for thermochromism was fabricated using an extrusion-based three-dimensional printing process. The printing material was prepared by mixing a thermochromic pigment and a thermoplastic polymer in various ratios. The effects of mixing ratio on the various properties of the fabricated membranes were experimentally investigated. It is presented that the fabricated lattice membrane had excellent thermochromic reaction, which was experimentally evaluated using a measurement of color brightness. The pigment content affected the diameter and surface morphology of the printed filament. The elastic modulus decreased, and thermochromic response became faster as the pigment concentration increased. Subsequently, a patch for fever detection was developed and then attached to the skin to demonstrate its color change according to body temperature. Results show that the fabricated thermochromic patch could be successfully applied to fever detection.

APA, Harvard, Vancouver, ISO, and other styles

48

Terasaki, Mark, Katsuya Miyake, and Paul L. McNeil. "Large Plasma Membrane Disruptions Are Rapidly Resealed by Ca2+-dependent Vesicle–Vesicle Fusion Events." Journal of Cell Biology 139, no. 1 (October 6, 1997): 63–74. http://dx.doi.org/10.1083/jcb.139.1.63.

Full text

Abstract:

A microneedle puncture of the fibroblast or sea urchin egg surface rapidly evokes a localized exocytotic reaction that may be required for the rapid resealing that follows this breach in plasma membrane integrity (Steinhardt, R.A,. G. Bi, and J.M. Alderton. 1994. Science (Wash. DC). 263:390–393). How this exocytotic reaction facilitates the resealing process is unknown. We found that starfish oocytes and sea urchin eggs rapidly reseal much larger disruptions than those produced with a microneedle. When an ∼40 by 10 μm surface patch was torn off, entry of fluorescein stachyose (FS; 1,000 mol wt) or fluorescein dextran (FDx; 10,000 mol wt) from extracellular sea water (SW) was not detected by confocal microscopy. Moreover, only a brief (∼5–10 s) rise in cytosolic Ca2+ was detected at the wound site. Several lines of evidence indicate that intracellular membranes are the primary source of the membrane recruited for this massive resealing event. When we injected FS-containing SW deep into the cells, a vesicle formed immediately, entrapping within its confines most of the FS. DiI staining and EM confirmed that the barrier delimiting injected SW was a membrane bilayer. The threshold for vesicle formation was ∼3 mM Ca2+ (SW is ∼10 mM Ca2+). The capacity of intracellular membranes for sealing off SW was further demonstrated by extruding egg cytoplasm from a micropipet into SW. A boundary immediately formed around such cytoplasm, entrapping FDx or FS dissolved in it. This entrapment did not occur in Ca2+-free SW (CFSW). When egg cytoplasm stratified by centrifugation was exposed to SW, only the yolk platelet–rich domain formed a membrane, suggesting that the yolk platelet is a critical element in this response and that the ER is not required. We propose that plasma membrane disruption evokes Ca2+ regulated vesicle–vesicle (including endocytic compartments but possibly excluding ER) fusion reactions. The function in resealing of this cytoplasmic fusion reaction is to form a replacement bilayer patch. This patch is added to the discontinuous surface bilayer by exocytotic fusion events.

APA, Harvard, Vancouver, ISO, and other styles

49

Walsh, K. B., J. P. Arena, W. M. Kwok, L. Freeman, and R. S. Kass. "Delayed-rectifier potassium channel activity in isolated membrane patches of guinea pig ventricular myocytes." American Journal of Physiology-Heart and Circulatory Physiology 260, no. 4 (April 1, 1991): H1390—H1393. http://dx.doi.org/10.1152/ajpheart.1991.260.4.h1390.

Full text

Abstract:

When the patch-clamp technique was used, a slowly activating, time-dependent outward current was identified in both cell-attached and excised membrane patches obtained from guinea pig ventricular myocytes. This macroscopic patch current was present in approximately 50% of patches studied and could be observed both in the presence and absence of unitary single channel activity (i.e., ATP-sensitive K+ channels). The time course of activation of the patch current resembled that of the whole cell delayed-rectifier K+ current (IK) recorded under similar ionic conditions, and the patch current and IK were activated over a similar membrane potential range. The time-dependent patch current could be eliminated when the Nernst potential for K+ equaled that of the pulse voltage. The patch current was inhibited by external addition of the tertiary ammonium compound LY 97241 (50 microM) and was augmented after internal application of the catalytic subunit of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (500 nM). Deactivating tail currents with kinetics similar to those of IK could be recorded to cell-attached and excised patches. Unitary single channel events underlying the time-dependent patch current could not be resolved despite various attempts to increase single channel conductance. Thus our results suggest that a major component of delayed rectification in guinea pig ventricular cells is due to the activity of a high-density, extremely low conductance K+ channel.

APA, Harvard, Vancouver, ISO, and other styles

50

Aguiar, José Lamartine de Andrade, Esdras Marques Lins, Silvio Romero de Barros Marques, Antônio Roberto de Barros Coelho, Renata de Oliveira Rossiter, and Roberto José Vieira de Melo. "Surgarcane biopolymer patch in femoral artery angioplasty on dogs." Acta Cirurgica Brasileira 22, suppl 1 (2007): 77–81. http://dx.doi.org/10.1590/s0102-86502007000700015.

Full text

Abstract:

PURPOSE: The objective of this study was to evaluate the use of the sugarcane biopolymer membrane in femoral artery patch angioplasty on dogs. METHODS: Eight dogs were submitted to bilateral femoral artery patch angioplasty with a sugarcane biopolymer membrane patch on one side and e-PTFE patch on the contralateral side. This research was performed at Experimental Surgical Research Laboratory of the Centro de Ciências da Saúde at Universidade Federal de Pernambuco. The dogs were submitted to a new surgery at 180 days after the patch angioplasty in order to harvest the femoral artery. All the animals were evaluated by: clinical examination, measure of femoral artery diameter, arteriogram and Doppler fluxometry. Yet the material harvested was sent to histological study. Each animal served as its own control. RESULTS: In all vessels of both groups there were no cases of infection, aneurysm formation, rupture or pseudoaneurysm formation and thrombosis. In both groups it was observed a chronic inflammatory reaction with lymphocytes, neutrophils and fibrosis in the outer surface of the patches. It was observed fibrosis in the inner surfaces of all the patches. In e-PTFE patches occurred invasion by fibroblasts. CONCLUSION: The sugarcane biopolymer membrane can be used as a patch in femoral artery angioplasty on dogs.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Patch de la membrane'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles