Human retinal pigmented epithelium (RPE) can be cultured by removing small patches of this layer from the choroid of the fetal eye. Such RPE patches give rise to healthy, epithelioid monolayers in vitro within 1-2 weeks without contamination from retinal or choroidal cells. The viability and proliferative capacity of these cultures is independent of the initial polarity of the patch. These RPE monolayers develop apical/basal polarity and a basal lamina and rest on a field of collagen fibers; they are capable of phagocytizing outer segments. A patch can be lifted off a confluent monolayer and transferred to another culture dish without risking the viability of either the old or the new culture. This provides a means of transplanting an organized, polarized patch of human RPE from one place to another.
Objective: The purpose of this study was to investigate the radioprotective features of 940 nm laser on the life span of mice, and absolute counts of blood cells and their proportions in gamma-irradiated mice. Background data: An important feature of laser light is activation of mitotic division and differentiation of cells, which may be useful in activation of hematopoiesis in gamma-irradiated organisms. Materials and methods: Mice were randomly assigned to 11 groups according to the type(s) of influence. Generally, mice were irradiated in three different ways: with laser at different fluences, with gamma irradiation, or by combination of laser at different fluences and gamma irradiation in a different order. Mice were treated with 940 nm laser at 3, 12, or 18 J/cm 2 and/or a lethal dose of gamma irradiation (8.7 Gy). Each group was randomly subdivided into two subgroups, in which the life span of the mice and blood cell counts (on 12th and 45th day after gamma irradiation) were analyzed. Results: Laser (940 nm) at a fluence of 3 J/cm 2 significantly prolonged the life span of gammairradiated mice ( p < 0.05). In the same group, counts of white blood cells, lymphocytes, and neutrophils were higher on day 12 than in the gamma group. On day 45 after gamma irradiation, some signs of hematopoiesis repair were found in blood. There were no significant differences in counts of erythrocytes, monocytes, neutrophils, or the proportion of neutrophils between this group and the control group. Conclusions: In summary, 940 nm laser at a fluence of 3 J/cm 2 demonstrates radioprotective features in an experiment with lethally irradiated mice. Mechanisms responsible for this effect will be investigated in further studies.
IntroductionMelatonin was proposed as a potential antiarrhythmic agent, and its antioxidative properties are considered to be the basis for the antiarrhythmic effect. The present study was aimed at the evaluation of association between ventricular tachycardia and/or ventricular fibrillation (VT/VF) incidence, oxidative stress parameters and electrophysiological changes in myocardial ischemia/reperfusion setting.Methods18 rats were treated by melatonin (10 mg/kg/day, orally) for 7 days, while 13 control animals were given placebo. The left anterior descending artery was reversibly ligated for 5 min to induce ischemia and subsequent reperfusion in the anesthetized animals. Unipolar electrograms were recorded from ventricular epicardium with a 64‐lead array connected to a custom‐made high‐resolution (4 kHz) mapping system. Local activation and repolarization times were measured as instants of dV/dt min during QRS complexes and dV/dt max during T waves in unipolar electrograms, respectively. Local repolarization durations and dispersion of repolarization were calculated. After experiments, the hearts were excised, and parameters of the oxidative stress were determined in ventricular myocardium.ResultsVT/VF incidence was less in the animals given melatonin as compared to controls (6/18 vs 9/13, p=0.047, respectively). Superoxide dismutase activity was higher in the melatonin group as compared to the control group (69.6±0.5 vs 60.2±2.0 inhibition rate %, p=0.001, respectively), while total antioxidant capacity, 4‐HNE adduct and total glutathione content did not differ in the studied groups. No parameters of oxidative stress were associated with arrhythmia susceptibility. Among the studied ventricular epicardial electrophysiological parameters, local activation times at the baseline (preischemic) state were both reduced by melatonin treatment (9.39±0.26 vs 10.58±0.33 ms, p=0.012) and associated with VT/VF incidence (B=1.872, 95% CI 1.106–3.169, p=0.020) in logistic regression analysis. No association between parameters of ventricular electrical excitation and oxidative stress were found.ConclusionThough chronic melatonin treatment enhanced enzymatic antioxidant activity, its antiarrhythmic action in ischemia/reperfusion model was associated with its direct effect on ventricular activation pattern.Support or Funding InformationThe study was supported by Russian Science Foundation (RSF 18‐15‐00309).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
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