Pericardial levels of 8-iso-PGF2alpha increase with the functional severity of heart failure and are associated with ventricular dilatation. These data suggest an important role for in vivo oxidant stress on ventricular remodeling and the progression to heart failure.
Electronic cigarettes (e-cigarettes) are becoming the fashionable alternative to decrease tobacco smoking, although their impact on health has not been fully assessed yet. The present study was designed to compare the impact of e-cigarette refill liquid (e-liquid) without nicotine to e-liquid with nicotine on rat testis. For this purpose, e-liquid with nicotine and e-liquid without nicotine (0.5 mg/kg of body weight) were administered to adult male Wistar rats via the intraperitoneally route during four weeks. Results showed that e-liquid with or without nicotine leads to diminished sperm density and viability, such as a decrease in testicular lactate dehydrogenase activity and testosterone level. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis identified a reduction in cytochrome P450 side-chain cleavage (P450 scc) and 17 beta-hydroxysteroid dehydrogenase (17βHSD) mRNA level, two key enzymes of steroidogenesis. Following e-liquid exposure, histopathological examination showed alterations in testis tissue marked by germ cells desquamation, disorganization of the tubular contents of testis and cell deposits in seminiferous tubules. Finally, analysis of oxidative stress status pointed an outbreak of antioxidant enzyme activities such as superoxide dismutase, catalase and gluthatione-S-transferase, as well as an important increase in sulfhydril group content. Taken together, these results indicate that e-liquid per se induces toxicity in Wistar rat testis, similar to e-liquid with nicotine, by disrupting oxidative balance and steroidogenesis.
Calcium uptake into isolated membrane vesicles from two patients with a grey platelet syndrome has been investigated. An increase in calcium transport appears in both patients when compared to controls. Determination of the kinetic parameters of the calcium transport system gave similar apparent affinity for calcium and an increase in the calcium uptake velocity. This increase in calcium transport is correlated with the increase of the associated Ca2+ activated ATPase activity. The results would suggest a new relationship between the ultrastructural and functional abnormalities of the grey platelet syndrome.
Gray platelets initially described as lacking α granules also show thrombin-induced aggregation and release lower than normal. One of the possible explanation is a modified intracellular Ca2+ concentration which is involved in platelet activation. We then decided to investigate the relationship between the morphological abnormality and a possible regulation of platelet Ca2+ concentration.We isolated a platelet membrane fraction (100,000 g) enriched in intracellular membranes which actively sequesters Ca2+. This Ca2+ uptake was mediated by a characterized (Ca2+ + Mg2+) ATPase.The isolated membrane vesicles from two patients show an increase in the calcium uptake. The stimulation reaches a factor 2 to 3 agd the Ca2+ uptake appears greatly increased whatever the Ca concentration used. This led us to investigate the Ca2+ + Mg2+ ATPase activity. The enzymatic activity appears increased in the first 10 minutes which correlates with the increased rate in calcium uptake. The specific activity of the enzyme is increased by a factor 2.4 to 2.7 which again agrees with the calcium uptake results. Therefore we suggest that the severe impairment in secretion found in the Gray platelets is probably related to the low cytoplasmic mobilization as it is found by Hardisty et al, 1985 ; this would be the consequence of an increased Ca2+ uptake rather than a decrease in the Ca liberation.The absence of α granules in Gray platelets together with the described abnormality in internal membranes and the recently described modification of external membrane fluidity (Rendu et al 1985) would suggest that these platelets have a general membrane disorder.
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