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http://www.webmedcentral.com/images/Header_Logo.giftext/html2010-11-06T10:25:09+01:00http://www.webmedcentral.com/Prof. Nataliya A BabenkoNatural C18:0-ceramide Induces Cellular Sphingolipid Accumulation And Apoptosis
http://www.webmedcentral.com/article_view/1100
Exogenous ceramides induces cell differentiation, cell cycle arrest and apoptosis in various cell types. However, the permeable short-chain ceramides have drawn more attention. In this study the effect of natural N-stearoyl-D-erythro-sphingosine (C18-ceramide) as well as short chain N-acetylsphingosine (C2-ceramide) and bovine brain non-hydroxy fatty acid ceramides on human keratinocyte growth and apoptosis and cellular sphingolipid accumulation was compared. Cells were cultered in the presence of 5-60 μM of ceramides or ethanol/dodecane for the 24 h. No significant release of lactate dehydrogenase was observed when the HaCaT cells were incubated with up to 60 μM of natural and C2-ceramides. Culturing of the cells in the presence of C18-ceramide leads to the concentration-dependent increase of the content of ceramide and sphingomyelin in the cells, reduction of keratinocyte proliferation, induction of cell apoptosis, and does not change the glucosylceramide content in the cells. It has been determined that the glucosylceramide synthase inhibitor D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol alone as well as combined with C18-ceramide was not toxic for HaCaT cells and did not enhanced the C18-ceramide-iuduced keratinocyte apoptosis. Comparison of biological activity of the ceramides species showed that natural C18-ceramide is the most potent inhibitor of the HaCaT cell growth and an inducer of cellular sphingolipid accumulation and cell apoptotic death.text/html2011-01-24T20:22:44+01:00http://www.webmedcentral.com/Dr. Zafer AkanProtective Role Of Quercetin: Antioxidants May Protect Cancer Cells From Apoptosis And Enhance Cell Durability
http://www.webmedcentral.com/article_view/1504
Quercetin is one of the most abundant dietary flavonoids widely present in many fruits and vegetables. Previous in vitro studies has shown that quercetin acts as an antioxidant and anti-inflammatory agent and it has potent anticarcinogenic properties as apoptosis inducer. In this study we examined apoptotic effects of quercetin on the K562 erythroleukemia cell line. K562 cells were induced to apoptosis by hydrogen peroxide and quercetin. Cell viability and apoptosis level were assessed by annexin V and PI staining method using flow cytometry. Viability of K562 cells was increased by low dose of quercetin (5-100 μM) during 3 hours. High dose of quercetin at toxic doses (100-500 μM) during 24 hours resulted with decrease of K562 cell viability as expected (P2O2 (150, 300, 600 µM). K562 cells were protected from H2O2induced apoptosis by the Quercetin (PAs indicated in previously studies, reduction of superoxides by the free radical scavengers such as quercetin could be beneficial for prevention of cancer but consumption of flavonoid free radical scavengers during cancer treatment may weaken effect of the chemotherapeutics and radiotherapy.text/html2013-05-07T08:38:04+01:00http://www.webmedcentral.com/Dr. Dipak K SahooIncreased germ cell apoptosis during testicular development and maturation by experimentally induced transient and persistent hypothyroidism
http://www.webmedcentral.com/article_view/4235
Oxidative stress is known to be one of the major factors to induce germ cell apoptosis. In our earlier research, it was reported that neonatal persistent and transient hypothyroidism cause prevalence of oxidative stress marked by elevated lipid peroxide levels, protein carbonyl contents with decreased antioxidant enzyme levels. Alteration in germ cell population was also marked in persistent and transient hypothyroid rat testis. In the present investigation, germ cell apoptosis were assessed by TUNEL in testicular sections and was found that significant apoptosis occurred in germ cells in the experimentally induced persistent and transient hypothyroid rats by 6-n-propyl-2-thiouracil (PTU). The number of TUNEL-positive cells (bright green spots) increases dramatically in case of the PTU-treated rat testis both for transient and persistent hypothyroidism in comparison to the controls. Nuclei were stained with DAPI and emitted blue fluorescence when excited with 405nm blue-diode laser. This also establishes the fact that hypothyroidism caused by PTU is linked with high testicular germ cell death rates. Such type of altered testicular physiology by hypothyroidism is reflected in adulthood with hampered fertility as evidenced by reduced total viable germ cells and sperm counts.