Niemann-Pick disease type C (NPC) was demonstrated in two successive pregnancies by strongly reduced activity of sphingomyelinase in amniotic fluid cells. By contrast, chorionic villi from the first pregnancy had shown normal sphingomyelinase activity. The prenatal diagnosis of NPC in the two fetuses was confirmed, after termination of the pregnancies, by (phospho)lipid analyses of the fetal li...

Cholesteryl ester–filled macrophages are the hallmark of atherosclerotic lesions. Unraveling the pathways responsible for lipid accumulation in macrophages has been viewed as an important aspect for understanding a piece of the atherosclerotic process.1 Investigations into the mechanisms through which macrophages accumulate cholesteryl esters from lipoproteins have delineated the involvement of...

Bacillus cereus sphingomyelinase belongs to the Mg(2+)-dependent neutral sphingomyelinase, which hydrolyses sphingomyelin to phosphocholine and ceramide, and acts as an extracellular hemolysin. The triplet residues, His151-Asp195-His296, of the enzyme are highly conserved among bacterial and mammalian Mg(2+)-dependent neutral sphingomyelinases. The triplet residues converge on the active-site p...

Lysosomal disintegration may cause apoptosis, necrosis and some diseases. However, mechanisms for these events are still unclear. In this study, we measured lysosomal beta-hexosaminidase free activity, membrane potential and intralysosomal pH. The results revealed that the cytosolic extracts of rat hepatocytes could increase the lysosomal permeability to both potassium ions and protons, and osm...

BACKGROUND Some of ginsenosides, root extracts from Panax ginseng, exert cytotoxicity against cancer cells through disruption of membrane subdomains called lipid rafts. Protopanaxadiol (PPD) exhibits the highest cytotoxic effect among 8 ginsenosides which we evaluated for anti-cancer activity. We investigated if PPD disrupts lipid rafts in its cytotoxic effects and also the possible mechanisms....

Erythrocyte injury such as osmotic shock, oxidative stress or energy depletion stimulates the formation of prostaglandin E2 through activation of cyclooxygenase which in turn activates a Ca2+ permeable cation channel. Increasing cytosolic Ca2+ concentrations activate Ca2+ sensitive K+ channels leading to hyperpolarization, subsequent loss of KCl and (further) cell shrinkage. Ca2+ further stimul...

Proliferating thyroid cells are more sensitive to UV-C radiations than quiescent cells. The effect is mediated by nuclear phosphatidylcholine and sphingomyelin metabolism. It was demonstrated that proton beams arrest cell growth and stimulate apoptosis but until now there have been no indications in the literature about their possible mechanism of action. Here we studied the effect of protons o...

Transcellular albumin transport occurs via caveolae that are abundant in lung microvascular endothelial cells. Stimulation of albumin transcytosis by proinflammatory mediators may contribute to alveolar protein leak in lung injury, yet the regulation of albumin transport and its underlying molecular mechanisms are so far incompletely understood. Here we tested the hypothesis that thrombin may s...