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This case series demonstrates how subretinal fluid is displaced immediately after pneumatic retinopexy with a small gas bubble injection in the vitreous cavity for superior rhegmatogenous retinal detachment. This series highlights the significant impact of the buoyant force applied to the detached retina by intravitreal gas in achieving retinal reattachment. Purpose: To demonstrate how a small gas bubble injected into the vitreous cavity in pneumatic retinopexy for rhegmatogenous retinal detachment causes immediate displacement of subretinal fluid and to gain insights into the potential mechanism of retinal displacement. Methods: Three patients with rhegmatogenous retinal detachment who underwent pneumatic retinopexy were enrolled and prospectively followed. All patients underwent ultra-widefield fundus photography at baseline and at 1 to 2 minutes after intravitreal gas injection. Results: In all cases, the ultra-widefield fundus photograph demonstrated immediate displacement of subretinal fluid, suggesting that the buoyant force applied to the retina by the bubble was responsible for the displacement of subretinal fluid. The results were extrapolated to determine the buoyant force applied by a small and large gas bubble as in pneumatic retinopexy and pars plana vitrectomy. We determined that the buoyant force applied with a larger bubble in pars plana vitrectomy was substantially greater, and this may lead to retinal displacement. Conclusion: Intravitreal gas applies significant buoyant force to the detached retina and subretinal fluid that leads to substantial and rapid displacement of subretinal fluid. Understanding the affect of the buoyant force of the gas bubble on the detached retina can provide insight into possible mechanisms of retinal displacement. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to assess the potential mechanisms of Hydrogen sulfide (H2S)-mediated cardioprotection with the use of a pharmacological preconditioning model. The study involves laboratory mice that were administered with H2S through an intravenous injection. Accordingly, the mice were put to 45 minutes of myocardial ischemia followed by reperfusion. The results show that antioxidant and antipoptic signaling produce large cardioprotective effects.

The article examines the effect of the antihyperglycemic drug metformin on the activation of adenylic acid (AMP)-activated protein kinase and on the left ventricular function and survival in heart failure. Metformin improved myocardial cell mitochondrial respiration and adenosine triphosphate (ATP) synthesis and improved left ventricular function and survival through the activation of AMPK and its mediators.

Purpose: To describe a novel positioning maneuver for patients with rhegmatogenous retinal detachment (RRD) following pneumatic retinopexy(PnR)., Methods: Single-center prospective case series of primary RRDs referred to St. Michael's Hospital, Toronto, Canada, between 2021 and 2023. All patients underwent PnR. Baseline ultra-widefield fundus imaging and repeat imaging 10 minutes after the gas injection was performed. After PnR, patients were instructed to perform the mini-steamroll maneuver which consists of a face-down position for ten minutes followed by positioning to the retinal break. The reduction of subretinal fluid (SRF) volume after the initial face-down position was evaluated with clinical examination and ultra-widefield imaging., Results: Six patients who presented with primary bullous RRD and a sizable superior break were enrolled. The mini-steamroll maneuver resulted in a rapid and significant reduction of SRF in all patients with bullous RRD and large superior breaks, allowing subretinal fluid to be expressed into the vitreous cavity with 10 minutes of face-down positioning. One patient required a sequential PnR. Primary retinal reattachment was achieved in all cases .This approach was well-tolerated by patients., Conclusion: This case series demonstrates that the mini-steamroll maneuver may be a suitable alternative for patient positioning following PnR in certain cases. The mini-steamroll is a simpler positioning regimen with the potential benefits of direct-to-break and full steamroller maneuver., Competing Interests: Conflict of Interest: RHM: Consultant for AbbVie, Alcon, Bausch +Lomb, Bayer, Novartis, Roche. Grants to Institution: Alcon, Bayer, Novartis. No conflicting relationship exists for any other author.

Background: Hydrogen sulfide (H(2)S) is an endogenous signaling molecule with potent cytoprotective effects. The present study evaluated the therapeutic potential of H(2)S in murine models of heart failure., Methods and Results: Heart failure was induced by subjecting mice either to permanent ligation of the left coronary artery for 4 weeks or to 60 minutes of left coronary artery occlusion followed by reperfusion for 4 weeks. Transgenic mice with cardiac-restricted overexpression of the H(2)S-generating enzyme cystathione gamma-lyase (alphaMHC-CGL-Tg(+)) displayed a clear protection against left ventricular structural and functional impairment as assessed by echocardiography in response to ischemia-induced heart failure, as well as improved survival in response to permanent myocardial ischemia. Exogenous H(2)S therapy (Na(2)S; 100 microg/kg) administered at the time of reperfusion (intracardiac) and then daily (intravenous) for the first 7 days after myocardial ischemia also protected against the structural and functional deterioration of the left ventricle by attenuating oxidative stress and mitochondrial dysfunction. Additional experiments aimed at elucidating some of the protective mechanisms of H(2)S therapy found that 7 days of H(2)S therapy increased the phosphorylation of Akt and increased the nuclear localization of 2 transcription factors, nuclear respiratory factor 1 and nuclear factor-E2-related factor (Nrf2), that are involved in increasing the levels of endogenous antioxidants, attenuating apoptosis, and increasing mitochondrial biogenesis., Conclusions: The results of the present study suggest that either the administration of exogenous H(2)S or the modulation of endogenous H(2)S production may be of therapeutic benefit in the treatment of ischemia-induced heart failure.