Hemoglobin in glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes is abnormally vulnerable to oxidative denaturation, which may release ferriheme, a known cytolytic agent. We found 13.3 nmol of ferriheme in G6PD-deficient erythrocyte membranes (per gram of total erythrocyte hemoglobin) using a spectrophotometric assay, as compared to 9.8 in normal membranes (P less than .05). After ...

Protection by ischemic preconditioning is lost in cardiomyocytes and hearts of heterozygous connexin 43 deficient (Cx43+/-) mice. Because connexin 43 (Cx43) is localized in cardiomyocyte mitochondria and mitochondrial Cx43 content is increased with ischemic preconditioning, we now tried to identify a functional defect at the level of the mitochondria in Cx43+/- mice by use of diazoxide and mena...

In order to clarify the role of oxidative processes in cytotoxicity we have studied the metabolism and toxicity of 2-methyl-1,4-naphthoquinone (menadione) and its 2,3 dimethyl (DMNQ) and 2,3 diethyl (DENQ) analogs in isolated rat hepatocytes. The two analogs, unlike menadione, cannot alkylate nucleophiles directly and were considerably less toxic than menadione. This decreased toxicity was cons...

cept on the vertical axis is 95. From the data plotted in accordance with equation 1, the values found for the dissociation constant Ki and the inactivation rate constant kinact were 38 ± 4 × 10 M and 1.05 ± 0.08 × 10 sec, respectively. These values compare very favorably with those for mechanismbased inhibitors of phosphatases. As shown in Figure 4, menadione shares critical structural feature...

Living cells typically contain numerous redox couples such as NAD+/NADH, NADP+/NADPH, cystine/cysteine, and the oxidized and reduced forms of glutathione and metalloenzymes. It is expected that the intracellular concentrations of these couples may change selectively with changes in the cellular environment, such as those due to hormones, growth factors, and nutrients. The present work employs a...

OmpW is a minor porin whose biological function has not been clearly defined. Evidence obtained in our laboratory indicates that in Salmonella enterica serovar Typhimurium the expression of OmpW is activated by SoxS upon exposure to paraquat and it is required for resistance. SoxS belongs to the AraC family of transcriptional regulators, like MarA and Rob. Due to their high structural similarit...

Stathmin 1 performs a critical function in cell proliferation by regulating microtubule polymerization. This proliferative function is thought to explain the frequent overexpression of stathmin in human cancer and its correlation with a bad prognosis. Whether stathmin also functions in cell death pathways is unclear. Stathmin regulates microtubules in part by binding free tubulin, a process inh...

BACKGROUND Extremely low frequency (ELF) magnetic fields (MF) are generated by power lines and various electric appliances. They have been classified as possibly carcinogenic by the International Agency for Research on Cancer, but a mechanistic explanation for carcinogenic effects is lacking. A previous study in our laboratory showed that pre-exposure to ELF MF altered cancer-relevant cellular ...

Mitochondrial dysfunction plays a crucial role in cell types that exhibit necrosis-like death after activation of their death program. Tumour necrosis factor (TNF) induces abnormal, perinuclear clustering of mitochondria from an evenly spread distribution throughout the cytoplasm. The mitochondria withdraw from the cell periphery and aggregate in a unipolar perinuclear cluster. TNF-induced mito...