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Query: UNIPROT:P30536 (PBS)
 9,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

LAL would not form a clot when mixed with a viscous, opaque parenteral preparation of iron dextran spiked with endotoxin. However, recoverable precipitate could be obtained by diluting the LAL iron dextran mixture with PBS and centrifuging. Although the pellet so formed was red colored the protein present could be quantitated by dissolving it in a Coomassie Blue stain solution. The very rapid change in color from reddish black to deep blue was measured quantitatively in a spectrophotometer and was sigmoidally related to the amount of endotoxin used to spike the iron dextran. This method is suggested to be generally useful to measure quantitatively endotoxin concentrations too low to form a clot with LAL but high enough to precipitate recoverable protein from LAL.
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PMID:Endotoxin determination in viscous opaque solutions of iron dextran by Limulus amebocyte lysate. 9 34

There is general agreement that the lung damage seen in paraquat poisoning is due to the generation of free radicals in alveolar epithelial cells. We have recently shown that the iron chelator and antioxidant deferoxamine (DF) reduces the mortality caused by paraquat in vitamin-E-deficient rats. In the present study we investigated the effect of DF and the lipid soluble iron chelator compound 51 (CP51) of the hydroxypyridin-4-one family on paraquat poisoning in rats with a normal vitamin E status and on isolated alveolar type II cells (ATTC). Adult rats were intravenously injected with a lethal dose of paraquat (40 mg/kg) while concurrent treatment with a continuous intravenous infusion of DF or CP51 was started. Survival of rats receiving DF at 25 and 50 mg/kg/24 h was not significantly increased compared with PBS-treated control animals. CP51, however, significantly (p less than 0.01) reduced the mortality caused by paraquat. When rats were treated with 25 mg/kg/24 h, eight of 15 rats survived the study period of 35 days compared with three in the PBS-treated control group (n = 27). In ancillary in vitro studies radiolabeled [51Cr]ATTC were incubated in a medium containing 100 microM paraquat in the absence or presence of DF and CP51. Paraquat-induced ATTC lysis increased to approximately 25% after 7 h of incubation. At the highest tested concentration (500 microM) of chelator, injury decreased markedly (80%), whereas at the lowest tested concentration (50 microM) cytotoxicity was not prevented.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of iron chelators on paraquat toxicity in rats and alveolar type II cells. 130 65

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.
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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.
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PMID:Extracellular reduction of alloxan results in oxygen radical-mediated attack on plasma and lysosomal membranes. 158 Oct 40

1. Endosomes were isolated from K 562 cells after 3 min after the endocytosis of a single cohort of transferrin molecules. 2. The change in 125I/59Fe ratio of heavy and light endosomes, relative to that of the transferrin used and 59Fe from light endosomes. 3. Incubation of heavy and light endosomes with PBS or PIH showed equal ATP specific iron release from both heavy and light endosomes, but in the presence of a NADH/NAD+ redox couple iron release from light endosomes was reduced. 4. Incubation of heavy and light endosomes with PIH and NEM did not completely abolish ATP specific iron release from heavy and light endosomes.
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PMID:Characteristics of iron release from isolated heavy and light endosomes. 316 66

Lactoferrin acquisition and iron uptake by pathogenic Trichomonas vaginalis was examined. Saturation binding kinetics were obtained for trichomonads using increasing amounts of radioiodinated lactoferrin, while no significant binding by transferrin under similar conditions was achieved. Only unlabeled lactoferrin successfully and stoichiometrically competed with 125I-labeled lactoferrin binding. Time course studies showed maximal lactoferrin binding by 30 min at 37 degrees C. Data suggest no internalization of bound lactoferrin. The accumulation of radioactivity in supernatants after incubation of T. vaginalis with 125I-labeled lactoferrin and washing in PBS suggested the presence of low affinity sites for this host macromolecule. Scatchard analysis indicated the presence of 90,000 receptors per trichomonad with an apparent Kd of 1.0 microM. Two trichomonad lactoferrin binding proteins were identified by affinity chromatography and immunoprecipitation of receptor-ligand complexes. A 30-fold accumulation of iron was achieved using 59Fe-lactoferrin when compared to the steady state concentration of bound lactoferrin. The activity of pyruvate/ferrodoxin oxidoreductase, an enzyme involved in trichomonal energy metabolism, increased more than sixfold following exposure of the parasites to lactoferrin, demonstrating a biologic response to the receptor-mediated binding of lactoferrin. These data suggest that T. vaginalis possesses specific receptors for biologically relevant host proteins and that these receptors contribute to the metabolic processes of the parasites.
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PMID:Iron uptake and increased intracellular enzyme activity follow host lactoferrin binding by Trichomonas vaginalis receptors. 608 62

This paper, which is the first part of four, deals with the potential risks of homologous blood transfusion as well as with normovolemic hemodilution, an autologous transfusion method, which is easily to be applied and not expensive. Although the various methods of autologous transfusion are well known for many years the public discussion on the "AIDS-topic" has led to a growing interest in blood-saving measures. However, in contrast to the so-called "AIDS-topic" the potential risks of a transfusion-transmitted hepatitis as well as the immunologic effects of homologous blood are of much greater importance. Moreover, high-court-sentences give the legal background for intensifying autologous transfusion and to offer it to the patients. So far there are four autologous transfusion methods to be applied routinely: 1. normovolemic hemodilution (NHD); 2. intra- and/or postoperative blood salvage (I/PBS) with or without autologous direct-retransfusion (ADR); 3. preoperative autologous plasmapheresis (PPH); 4. preoperative autologous blood donation (ABD). Moreover, drug-induced stimulation of the erythropoiesis by means of erythropoietin and the additional (intravenous) administration of iron may become a further component among autologous transfusion methods. Normovolemic hemodilution means exchange of autologous blood versus an artificial colloid. To make sure for normovolemia is to be considered a "conditio sine qua non" for "functioning" of normovolemic hemodilution.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The present possibilities for routine use of blood-saving measures from the anesthesiologic point of view--theoretical basis and clinical practice. I. Potential risks of homologous transfusion; normovolemic hemodilution]. 814 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.
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PMID:Heme oxygenase expression in Swiss 3T3 cells following exposure to aqueous cigarette smoke fractions. 829 50

Serum antibody responses to the 70, 77, and 100 kDa iron-regulated outer membrane proteins (IROMPs) of Pasteurella haemolytica A1 were studied in cattle vaccinated with outer membrane protein (OMP) enriched outer membrane fraction, IROMP-enriched outer membrane fraction or live P. haemolytica. Vaccination with an IROMP-enriched outer membrane fraction stimulated antibodies to the 70 kDa IROMP, whereas vaccination with live P. haemolytica stimulated antibodies to the 70 and 77 kDa IROMPs. In a second experiment, sera were used from cattle vaccinated with live or killed P. haemolytica and subsequently challenged. Significant antibody responses to OMP- and IROMP-enriched outer membrane fractions were detected by an enzyme-linked immunosorbent assay (ELISA) for cattle vaccinated with bacterins or live P. haemolytica. Regression analysis indicated significant correlations between high antibody responses to the OMP- or IROMP-enriched fraction and resistance to challenge. Antibody responses to the 70 and 77 kDa IROMPs were significantly greater for the live P. haemolytica vaccinates than for PBS control vaccinates. There was no significant correlation between antibody responses to individual IROMPs and resistance or susceptibility to challenge. These data suggest that antibodies to IROMPs alone are probably not responsible for protective immunity against pneumonic pasteurellosis. Antibodies to IROMPs, however, in conjunction with antibodies to other surface antigens probably enhance immunity to P. haemolytica challenge.
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PMID:Serum antibody responses of cattle to iron-regulated outer membrane proteins of Pasteurella haemolytica A1. 853 87

Acquisition of iron from lactoferrin and transferrin by a parasitic protozoon Tritrichomonas foetus has been studied in vitro. Specific, time-dependent, and saturable binding of iodinated ligands to the outer membrane of T. foetus at 4 degrees C was demonstrated for 125I-labeled lactoferrin only. About 1.7 x 10(5) binding sites of a single class with Kd approximately equal to 3.6 microM was estimated by means of Scatchard analysis. Internalization of the bound lactoferrin was observed at 37 degrees C. The cell-associated radioactivity after 30 min incubation of the parasite with 125I-lactoferrin at 37 degrees C was about 3.5-fold higher than the amount bound at 4 degrees C. The majority of internalized 125I-lactoferrin was released within 15 min of cell reincubation at 37 degrees C in the presence of a 100-fold excess of nonlabeled lactoferrin. Released lactoferrin displayed unchanged mobility on autoradiography. In contrast to lactoferrin, binding of 125I-transferrin was nonspecific and did not display saturable kinetics. The growth of T. foetus in iron-restricted media was stimulated by both lactoferrin and transferrin. The ability of the cells to remove and accumulate iron from both proteins was therefore examined using 59Fe-saturated lactoferrin and transferrin. It was found that trichomonads acquired a comparable amount of iron from both lactoferrin and transferrin during 60 min incubation at 37 degrees C (495 and 577 pmole Fe/mg of protein, respectively). The pH of the assay medium (PBS) decreased from pH 7.4 to 5.6 after incubation with trichomonads. At this pH, marked release of iron from transferrin (up to 47%) but not from lactoferrin (4%) was determined in cell-free media. These results indicate that T. foetus is able to utilize both lactoferrin and transferrin to cover its iron requirements. However, mechanisms of iron acquisition from these host proteins appear to be different. Specific binding and internalization of lactoferrin suggests the possible involvement of receptor-mediated endocytosis in the acquisition of lactoferrin-bound iron, while retrieval of iron from transferrin may depend on the extracellular release of iron from this ligand.
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PMID:Tritrichomonas foetus: iron acquisition from lactoferrin and transferrin. 868 90


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