Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytotoxic effects of alloxan are not understood in any great detail, although they are considered to involve reactions mediated by oxygen-derived free radicals. These reactive species may form extra-or intracellularly following alloxan reduction, and result in cell damage through a number of complex interactions with a variety of macromolecules. The purpose of the present study was to elucidate further the early intracellular effects of alloxan on a model system of macrophage-like cells in culture. Addition of alloxan (15 mM), without reducing agents, to the medium surrounding the cells (phosphate-buffered saline, PBS, 37 degrees C, pH 7.4) resulted in rapid lysosomal damage (disappearance of the proton gradient over the membrane) followed by severe cellular degeneration (swelling and blebbing) and 50% cell death (trypan blue dye exclusion test) within fifty min. Cells pretreated with the gamma-glutamyl cysteine synthetase-inhibiting agent BSO, to decrease levels of intracellular glutathione, showed enhanced sensitivity to alloxan. The results are interpreted as indicating the cytotoxicity to result from intracellular formation of superoxide radicals, hydrogen peroxide and hydroxyl radicals, the latter within secondary lysosomes containing trace amounts of reactive iron (inducing Fenton reactions). The ensuing lysosomal membrane damage may result in leakage of lysosomal hydrolases and further cellular degeneration.
 ...
PMID:Alloxan cytotoxicity involves lysosomal damage. 158 Oct 39

Alloxan participation in extracellular redox processes results in the formation of the reactive oxygen species (ROS) superoxide anions (O2-), hydroxyl radical (OH.) and hydrogen peroxide (H2O2), causing cell damage through a number of complex interactions probably involving several different cellular structures. These involve the plasma membrane, and we have recently presented evidence for lysosomal interference. The present study elucidates the early (within 15 min) events in a model system of macrophage-like cells (J-774) in culture. Addition of 2 mM alloxan and 1 mM cysteine to the medium surrounding the cells (phosphate-buffered saline, PBS, 37 degrees C, pH 7.4) resulted in rapid lysosomal membrane damage with disappearance of the proton gradient as visualized by acridine orange relocalization, as well as plasma membrane alterations leading to increased leakage of fluorescein after fluorescein diacetate staining. These events were later (greater than 30 min) followed by cellular degeneration in the form of blebbing. Mitochondrial damage (rhodamine 123 relocalization) was a late event. Cells pretreated with desferrioxamine (Des) and superoxide dismutase (SOD) or Des, SOD and catalase (CAT) to induce partial (H2O2 formation only) or almost full protection (no ROS formation) showed about the same reactions as when cells were exposed to alloxan and cysteine without scavengers (O2-, H2O2 and OH. formation) or with PBS only, respectively. The results are interpreted as indicating that the cytotoxicity is a consequence mainly of H2O2 involvement and probably of lysosomal influx of H2O2 with ensuing OH.formation within secondary lysosomes containing trace amounts of reactive iron. It is suggested that the resultant lysosomal membrane damage is followed by leakage of lysosomal hydrolases and ensuing cellular degeneration.
 ...
PMID:Extracellular reduction of alloxan results in oxygen radical-mediated attack on plasma and lysosomal membranes. 158 Oct 40

The antibacterial activity and adherence-enhancing effects of nonoxynol-9 were evaluated against vaginal and uropathogenic bacteria. Nonoxynol-9 was markedly less active against the 43 uropathogenic bacterial and yeast strains tested (MIC90, greater than 32%) than against the 26 Gardnerella vaginalis strains (MIC90, less than or equal to 0.015%) and the 53 Lactobacillus strains (MIC90, 8%) tested. Hydrogen peroxide-producing strains of Lactobacillus were more susceptible to nonoxynol-9 (MIC90, 4%) than nonproducers (MIC90, 16%). Two Escherichia coli strains that expressed type 1 fimbriae and three vaginal strains of lactobacilli adhered in significantly higher numbers to vaginal epithelial cells preincubated with 5% nonoxynol-9 than to control cells preincubated with PBS. Spermicides may provide a selective advantage in colonizing the vagina with nonoxynol-9-resistant uropathogens such as E. coli, perhaps via a reduction in vaginal lactobacilli (especially hydrogen peroxide-producing strains) and through enhancement of adherence of E. coli to epithelial cells.
 ...
PMID:Nonoxynol-9: differential antibacterial activity and enhancement of bacterial adherence to vaginal epithelial cells. 165 2

alpha-Tocopherol contained in human blood cells was oxidized by a photosensitized reaction in the presence of hematoporphyrin as a photosensitizer. Participation of singlet molecular oxygen, superoxide radical and hydrogen peroxide in the photooxidation was not so significant, although hematoporphyrin can generate singlet molecular oxygen on illumination. Quercetin inhibited the photooxidation of alpha-tocopherol. Both in the presence and in the absence of linoleic acid, photooxidation of alpha-tocopherol which was suspended in the PBS solution was also inhibited by quercetin. The rate of the photooxidation of alpha-tocopherol in the presence of linoleic acid was faster than that in the absence of the fatty acid. When quercetin inhibited the photooxidation of alpha-tocopherol contained in blood cells or suspended in PBS solution, quercetin was oxidized. The photooxidation of quercetin, which was suspended in the PBS solution, was inhibited by alpha-tocopherol in the absence of linoleic acid, but stimulated in the presence of the fatty acid.
 ...
PMID:[Effects of quercetin on photosensitized oxidation of alpha-tocopherol in human blood cells in the presence of hematoporphyrin]. 213 61

The chemotactic activity of elastin-derived peptides (EP) for human polymorphonuclear leukocytes (PMNL) was investigated using the under agarose method. The EP were produced by digesting the bovine ligament elastin with porcine pancreatic elastase. Thus prepared digest had weak chemotactic activity for PMNL. The mean chemotactic index for all tested EP concentrations did not exceed 1.30 and was lower than that obtained with zymosan-activated serum (ZAS, n-formyl-methionyl-leucyl-phenylalanine (FMLP) 2.2 +/- 0.40, 3.1 +/- 0.32, (n = 10) respectively. However, EP (50 micrograms) after injection to the mouse pleural cavity induced PMNL influx. The mean PMNL number found in this cavity was 0.09 +/- 0.03 x 10(6) for PBS and 0.18 +/- 0.03 +/- 10(6) for EP injection (p less than 0.01 n = 6). Human PMNL during 60 min incubation with EP (1 to 10 micrograms/ml) or with EP and cytochalasin B (CB 4.8 micrograms/ml) released myeloperoxidase and low amounts of hydrogen peroxide. At 1 micrograms/ml and in presence of CB elastin digest was nearly as active in myeloperoxidase release as FMLP (300 ng/ml). The values reached 17.1 +/- 2.5 and 19.7 +/- 2.1% of the total activity of whole cell lysate, respectively. The obtained results suggest that EP produced in vivo in the site of inflammation could modulate to some extent its course by enhancing PMNL influx and their activation. It seems that such mechanism of enhancement of the inflammatory response may occur in the lungs which are rich in elastin fibers.
 ...
PMID:Chemotactic activity of elastin-derived peptides for human polymorphonuclear leukocytes and their effect on hydrogen peroxide and myeloperoxidase release. 256 30

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals.
 ...
PMID:Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke. 264 5

An optimal fixation method and intensification procedure may be required in brain immunohistochemistry to obtain intense and widespread staining for a specific antigen, in cases where ordinary fixation and conventional immunohistochemistry result in only partial demonstration of the antigen. In the present study of localization of corticotropin-releasing factor immunoreactivity (CRFI) in rat brain, the importance of such intensification is shown. We describe a fixation procedure in which perfusion of rat brain with Bouin's solution is followed by a PBS wash and a further perfusion with either Zamboni's fluid or 4% paraformaldehyde in 0.1 M phosphate buffer (pH 7.4), for subsequent investigation of the detailed localization of CRFI in cerebral cortex and subcortical structures. The cobalt-glucose oxidase-diaminobenzidine (Co-GOD) intensification method has been modified to increase the sensitivity of immunostaining by reducing the concentration of glucose oxidase, which is added to the final incubation solution as a generator of hydrogen peroxide. The use of cobalt acetate instead of cobalt chloride appears to slightly suppress background staining in the Co-GOD method. Combination of the two modified procedures was applied to visualize intense and widespread CRFI in a variety of rat brain regions, including median eminence, cerebral cortex, and central amygdaloid nucleus.
 ...
PMID:Improved fixation and cobalt-glucose oxidase-diaminobenzidine intensification for immunohistochemical demonstration of corticotropin-releasing factor in rat brain. 349 48

Treatment of human lymphocytes with hydrogen peroxide (10 microM, 30 min, 37 degrees C in PBS) or with 1 cGy X-rays evoked about a 30% decrease in the frequency of micronuclei upon subsequent X-irradiation (1.5 Gy). In addition to a lower micronuclei frequency, we also found an increase in the sedimentation distance of the nucleoids, when measured 90 min (duration of the isolation procedure carried out at 4 degrees C) after the adaptive dose (hydrogen peroxide or X-rays) and preceding the challenge dose. To test whether Ca2+ is involved in the induction of the adaptive response pathway, we treated cells with the calcium chelator, EGTA. When EGTA was given at the same time as the adaptive dose, it prevented the development of the adaptive response. In addition, the calcium antagonist, TMB-8, also prevented the development of the adaptive response as it prevented the reduction of both micronuclei and increased nucleoid sedimentation. Cellular treatment with TMB-8 increased the free [Ca2+] by 40%, when given together with hydrogen peroxide. The faster sedimenting nucleoids from adapted cells were also examined by ethidium bromide titration; there was no indication of any change in supercoil density or loop size. Psi-tectorigenin, an inhibitor of phosphatidylinositol turnover, did not modify the adaptive response, indicating that inositol (1,4,5)-trisphosphate is not involved in the induction of the adaptive response, but free Ca2+ ions are.
 ...
PMID:Calcium antagonist, TMB-8, prevents the induction of adaptive response by hydrogen peroxide or X-rays in human lymphocytes. 802 16

A dose-dependent and transiently elevated expression of a cytoplasmic 32 kDa protein was observed in Swiss albino 3T3 fibroblasts exposed to mainstream cigarette smoke (CS) trapped in phosphate-buffered saline solutions (smoke-bubbled PBS). The protein was identified as heme oxygenase (HO) (heme, hydrogen donor:oxygen oxidoreductase, EC 1.14.99.3) by Western blotting using an anti-rodent HO-specific antibody. Kinetic investigations revealed that HO protein and its mRNA were detectable in smoke-bubbled PBS-treated cells between 1 and 24 h after exposure to 0.03 puffs (approximately 1 cm3) CS per ml medium. As a result of transcriptional activation, a nearly 50-fold increase in the amount of HO mRNA was determined after 8 h exposure compared to control levels. Since literature data indicate that there is a link between glutathione depletion and HO expression, the same was assumed for cells exposed to smoke-bubbled PBS, as a decrease of more than 60% in glutathione levels was observed after the exposure. This was further supported by the observation that no elevated amounts of HO mRNA appeared in smoke-bubbled PBS-treated cells when cysteine was exogenously added. However, although these effects may be attributable to the formation of hydroxyl radicals (which have been shown to induce HO and to deplete glutathione levels and which appear in aqueous smoke-containing solutions via the iron-catalysed Fenton reaction) neither catalase nor the iron cation chelating agent o-phenanthroline were able to suppress or even to reduce HO expression in smoke-bubbled PBS-treated cells. On the contrary, at comparable concentrations both compounds were found to be potent inhibitors of smoke-dependent DNA strand breaks. Hence, reactive species other than Fenton reaction-derived hydroxyl radicals are responsible for the effects observed in the present study.
 ...
PMID:Heme oxygenase expression in Swiss 3T3 cells following exposure to aqueous cigarette smoke fractions. 829 50

Hyaluronan (HA) is a highly hydrated polyanion, which is a network-forming and space-filling component in the extracellular matrix of animal tissues. Confocal fluorescence recovery after photobleaching (confocal-FRAP) was used to investigate intramolecular hydrogen bonding and electrostatic interactions in hyaluronan solutions. Self and tracer lateral diffusion coefficients within hyaluronan solutions were measured over a wide range of concentrations (c), with varying electrolyte and at neutral and alkaline pH. The free diffusion coefficient of fluoresceinamine-labeled HA of 500 kDa in PBS was 7.9 x 10(-8) cm(2) s(-1) and of 830 kDa HA was 5.6 x 10(-8) cm(2) s(-1). Reductions in self- and tracer-diffusion with c followed a stretched exponential model. Electrolyte-induced polyanion coil contraction and destiffening resulted in a 2.8-fold increase in self-diffusion between 0 and 100 mM NaCl. Disruption of hydrogen bonds by strong alkali (0.5 M NaOH) resulted in further larger increases in self- and tracer-diffusion coefficients, consistent with a more dynamic and permeable network. Concentrated hyaluronan solution properties were attributed to hydrodynamic and entanglement interactions between domains. There was no evidence of chain-chain associations. At physiological electrolyte concentration and pH, the greatest contribution to the intrinsic stiffness of hyaluronan appeared to be due to hydrogen bonds between adjacent saccharides.
 ...
PMID:The molecular basis of the solution properties of hyaluronan investigated by confocal fluorescence recovery after photobleaching. 1051 40


1 2 3 4 5 6 7 8 9 10 Next >>