Human amniotic membrane for failed macular hole. A case of initial unsuccessful outcome that resolved after amniotic membrane exchange

Introduction We described a case of initial unsuccessful outcome of failed macular hole treated with amniotic membrane, that resolved after amniotic membrane exchange and silicone oil injection. Case Description a woman affected by a high myopic macular hole that had failed to close after multiple surgeries, had been treated using an amniotic membrane graft and 20% sulfur hexafluoride but, after the gas reabsorption, the macular hole was still open, and the amniotic membrane. A second surgery with a second amniotic membrane patch and silicone oil was carried out. Two weeks after the procedure the macular hole closed, and the final visual acuity improved from 20/400 to 20/100. Conclusions In this case, a second surgery, using a new amniotic membrane graft and a longer-lasting endotamponade, closed the hole and improved the visual acuity.

An inter-channel cooperative mechanism mediates PIEZO1's exquisite mechanosensitivity

The bowl-shaped structure of PIEZO channels is predicted to flatten in response to mechanical stimuli, gating their pore open. However, how this unique structure allows them to detect exquisitely small changes in membrane tension remains unclear. Here, using pressure clamp electrophysiology, modeling, and molecular dynamics simulations, we show that the single channel open probability of PIEZO1 increases weakly with respect to pressure-induced tension. In contrast, when multiple channels are present in a membrane patch, channel open probability increases steeply as a function of the number of open channels. These cooperative effects are consistent with an inter-channel energetic repulsion due to the local membrane deformation created by the non-planar PIEZO structure. When channels open, this deformation shrinks, allowing open channels to diffuse closer to each other, thus delaying closure. This study reveals how PIEZO1 channels acquire their exceptional mechanosensitivity.

Multi-dimensional and spatiotemporal correlative imaging at the plasma membrane of live cells to determine the continuum nano-to-micro scale lipid adaptation and collective motion

The primary cilium is a specialized plasma membrane protrusion with important receptors for signalling pathways. In polarized epithelial cells, the primary cilium assembles after the midbody remnant (MBR) encounters the centrosome at the apical surface. The membrane surrounding the MBR, namely remnant associated membrane patch (RAMP) once situated next to the centrosome, releases some of its lipid components to form a centrosome-associated membrane patch (CAMP) from which the ciliary membrane stems. The RAMP undergoes a spatiotemporal membrane refinement during the formation of the CAMP, which becomes highly enriched in condensed membranes with low lateral mobility. To better understand this process, we have developed a correlative imaging approach that yields quantitative information about the lipid lateral packing, its mobility and collective assembly at the plasma membrane at different spatial scales over time. Our work paves the way towards a quantitative understanding of lipid collective assembly at the plasma membrane spatiotemporally as a functional determinant in cell biology and its direct correlation with the membrane physicochemical state. These findings allowed us to gain a deeper insight into the mechanisms behind the biogenesis of the ciliary membrane of polarized epithelial cells.

Lyophilized amniotic membrane patch (LAMPatch) as a replacement of tamponades in the treatment of primary rhegmatogenous retinal detachment

Background The basis of retinal detachment repair is sealing the retinal breaks. In order to seal the retinal breaks, chorioretinal adhesion around these lesions has to be achieved. Laser retinopexy is not immediate thus necessitates the use of a temporal endotamponade to maintain both tissues in apposition. We propose the use of a patch of lyophilized human amniotic membrane (LAMPatch) in order to occlude the retinal tear effectively until the chorioretinal adhesion is settled, overcoming the risks and limitations of the current tamponades. Methods 23-gauge vitrectomy was performed on eyes with primary retinal detachment with single retinal breaks of less than one-hour extension. A LAMPatch was deployed over the retinal breaks after retina was repositioned with perfluorocarbon. Neither gas nor silicon oil were injected. Results Six eyes of six patients with total or partial retinal detachment were included. Retinas remained reattached in all cases until the end on follow-up (3, 5 months). Best-corrected visual acuity at 1-week postop was between 20/30 and 20/100. Neither elevations of intraocular pressure, cataracts nor signs of inflammation were registered during follow-up. No second surgeries were needed. Conclusion This technique has proven to be safe and effective in this small case series. No intraocular pressure rise, inflammation or cataracts were registered until last follow-up visit.

Amniotic Membrane Patch Graft in Management of Double Chamber after Deep Anterior Lamellar Keratoplasty

Purpose: To describe a novel technique of amniotic membrane (AM) patch graft in the management of double chamber treatment after big-bubble deep anterior lamellar keratoplasty (DALK). Case Report: A 35-year-old male patient with advanced keratoconus underwent bigbubble DALK. Manual lamellar dissection was done due to failed big-bubble. First-day postoperative double chamber was detected. Air bubbling and SF6 injection were tried without any success. Double chamber resolved by fixation of AM transplantation patch graft (1 × 1 mm) over the Descemet’s membrane perforation with fibrin glue. Conclusion: Amniotic membrane patch graft can be used in the management of double chamber after DALK not responsive to intracameral gas injection.

Estimation of the Oxidative Deterioration of Turbine Oil Using Membrane Patch Color

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.

Amniotic membrane for retinal detachment due to paravascular retinal breaks over patchy chorioretinal atrophy in pathologic myopia

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.