Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extensive skeletal muscle injury, whether caused by mechanical crush or by extreme physical exertion, is incompatible with life, unless treated early and vigorously. The immediate cause of morbidity is leakiness of the sarcolemmal membrane to cardiotoxic or nephrotoxic cations and metabolites (K, PO4, myoglobin and urate) of the sarcoplasma, and rapid massive uptake by the muscles of extracellular fluid, sodium and calcium, leading to profound hypovolemic and hyocalcemic shock. Casualties who survive the early steep of hyperkalemia and arterial hypotension are susceptible to myoglubinuric acute renal failure owing mainly to the combination of renal vasoconstriction, nephrotoxicity, and tubular obstruction by myoglobin plugs and urate. Management includes immediate (prehospital) intravenous volume replacement followed by mannitol-alkaline diuresis. The alkali regimen ameliorates the acidosis associated with shock and the hyperkalemia, and protects against the nephrotoxicity of myoglobin and urate by alkalinization of the urine. Mannitol, through its impermeant hyperoncotic properties, decompresses and mobilizes muscle edema and promotes renal tubular flow, thus flushing myoglobin plugs and enhancing urinary elimination of nephrotoxic metabolites. With this regimen and when necessary also with the use of dialysis, a substantial salvage of lives, limbs, and kidney function has been achieved recently compared with invariable mortality for casualties who were buried for 3 to 4 hours or more in the early 1940s (World War 2).
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PMID:Acute renal failure complicating muscle crush injury. 975 9

A novel method is reported for quantifying protein adsorption to naked silica tubings and for assessing the efficacy of amino quenchers added to the background electrolyte. It consists of flushing a fluorescently-labelled protein (myoglobin) into a capillary equilibrated in Tris-acetate buffer, pH 5.0, until full saturation of the potential adsorbing sites. Desorption is then affected by driving electrophoretically sodium dodecyl sulphate (SDS) micelles into the capillary from the cathodic reservoir: the peak of eluted material is quantified fluorometrically by using a dual laser beam instrument able to read the fluorescein-isothiocyanate-labelled myoglobin at 520 nm and the internal standard (sulphorodamine) at 630 nm. As potential quenchers, a series of monoamines have been investigated (triethylamine, triethanolamine, ethylamine), followed by diamines (putrescine, cadaverine and hexamethonium bromide) and finally by oligoamines [spermidine, spermine and TEPA (tetraethylenepentamine), i.e., a tri- a tetra- and a pentamine, respectively]. Two values of molarities have been derived: a value at 50% (a kind of a dissociation constant) and a value at 90% inhibition of binding of macromolecules to the silica surface. According to these figures of merit, mono- and diamines are rather poor quenchers of interaction with the wall, since the 50% values are of the order of 50-100 mM and the 90% values reach as high as 560 mM. On the contrary, oligoamines, especially spermine and TEPA, are most effective, since the 50% molarities are in the sub-millimolar range and the 90% values are of the order of ca. 1 mM. Figures of merit have also been derived for different washing procedures. Those most commonly adopted in routine practice, i.e., of washing with either 1 M NaOH or with 1 M HCl, or with both, leave behind traces of proteins still bound to the wall, whereas the SDS micelle electrophoretic desorption seems to be 100% effective.
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PMID:Protein adsorption to the bare silica wall in capillary electrophoresis quantitative study on the chemical composition of the background electrolyte for minimising the phenomenon. 1067 82

A novel method is reported for quantifying protein adsorption to naked silica tubings and for assessing the efficacy of polymers added to the background electrolyte as dynamic wall modifiers. It consisted of flushing a fluorescently-labelled protein (myoglobin) into a capillary equilibrated in Tris-acetate buffer, pH 5.0, until full saturation of the potential adsorbing sites. Desorption was then affected by electrophoretically driving sodium dodecyl sulphate micelles into the capillary from the cathodic reservoir: the peak of eluted material is quantified by using a dual laser beam instrument able to read the fluorescein isothiocyanate-derivatized myoglobin at 520 nm and the internal standard (sulphorodamine) at 630 nm. Four polymers have been assessed as potential quenchers of interaction of proteins with the silica wall: hydroxypropylmethylcellulose (HPMC, Mr = 1000000), hydroxyethylcellulose (HEC, Mr = 27000), poly(vinyl alcohol) (PVA, Mr = 49000) and short-chain poly(dimethylacrylamide) [poly(DMA)] (average Mr ca. 150000). HPMC, poly(DMA) and PVA were effective in the 0.005 to 0.02% (w/v) range, whereas HEC was active in the 0.1 to 0.8% concentration range. All polymers, however, except for poly(DMA), exhibited a rather poor performance in suppressing protein interactions with the siliceous surface, and could inhibit adsorption only by, at most, 50% (contrary to oligoamines which can quench such interactions by >90%). It is hypothesized that dynamically adsorbed polymers leave ample regions of the capillary inner surface unmasked, thus allowing strong interactions of proteins with the silica wall. This is also confirmed by the modest reduction of electroendoosmotic flow upon polymer adsorption, as compared with an untreated silica surface. Although poly(DMA) can inhibit protein adsorption by as much as 85%, its hydrophobic nature could in turn provide more adsorption sites for less hydrophilic proteins than myoglobin.
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PMID:Quantitative studies on the adsorption of proteins to the bare silica wall in capillary electrophoresis. II. Effects of adsorbed, neutral polymers on quenching the interaction. 1081 68

Reduction of ferric myoglobin (metmyoglobin, MetMb) to its ferrous form is important for maintaining fresh meat color because only reduced myoglobin can bind oxygen to form the consumer-preferred cherry red color in fresh meat. The objective of this study was to characterize an apparent mitochondria electron transport chain (ETC)-linked pathway for MetMb reduction in vitro. MetMb was reduced in the presence of mitochondria and succinate (p < 0.05); mitochondria or succinate alone did not facilitate MetMb reduction relative to controls (p > 0.05). Flushing samples with oxygen greatly decreased MetMb reduction, while flushing with argon increased MetMb reduction when compared with controls (p < 0.05). ETC inhibitors were used to localize the site where electrons became available for MetMb reduction. MetMb reduction was increased by rotenone addition and decreased by malonic acid (p < 0.05); the reduction was completely abolished by additions of antimycin A or myxothiazol when compared with controls (p < 0.05). These results suggest that electrons become available for MetMb reduction at a site(s) between complex III and IV. Mitochondrial ETC-linked MetMb reduction increased with increased mitochondrial density and succinate concentration (p < 0.05); the greatest MetMb reduction was observed at pH 7.2 and 37 degrees C, and ETC-linked MetMb reducing activity decreased with time postmortem (p < 0.05). These results indicate that ETC-linked MetMb reduction exists but would be minimally active in postmortem muscles.
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PMID:Mitochondrial reduction of metmyoglobin: dependence on the electron transport chain. 1596 32

The suitability of noncovalently bilayer-coated capillaries for the analysis of proteins by capillary electrophoresis (CE) at medium pH was investigated. Fused-silica capillaries were coated simply by successively flushing with a polybrene (PB) and a poly(vinyl sulfonate) (PVS) solution. A protein test mixture was used to evaluate the performance of the coated capillaries. Comparisons with bare fused-silica capillaries were made. Several background electrolytes (BGEs) were tested in combination with the PB-PVS coating, showing that optimum performance was obtained for the proteins using high BGE concentrations. With a 300 mM Tris phosphate buffer (pH 7.0), good plate numbers (150,000-300,000), symmetrical peaks, and favorable migration-time repeatabilities (RSDs below 0.8%) were obtained for the proteins. Using bare fused-silica capillaries, the protein peaks were significantly broadened and the migration-time RSDs often exceeded 5%. It is concluded that the PB-PVS coating effectively minimizes adverse protein adsorption and provides a very stable electroosmotic flow (EOF). We also investigated the potential of a commercially available bilayer coating (CEofix) for protein analysis. It is demonstrated that with this coating, good plate numbers and peak symmetries for proteins can be achieved when the CEofix BGE ("accelerator") is replaced by a common BGE such as sodium or Tris phosphate. Apparently, the negatively charged polymer present in the "accelerator" interacts with the proteins causing band broadening. The utility of the bilayer coatings is further illustrated by the separation of proteins such as interferon-alpha 2b, myoglobin and carbonic anhydrase, by the analysis of a degraded insulin sample in time, and by the profiling of the glycoprotein ovalbumin. In addition, it is demonstrated that even in the presence of concentrations of human serum albumin in the sample of up to 60 mg/mL, the PB-PVS coating still provides reproducible protein separations of good performance.
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PMID:Noncovalently bilayer-coated capillaries for efficient and reproducible analysis of proteins by capillary electrophoresis. 1607 6

Nitric oxide (NO) may limit myocardial ischemia-reperfusion injury by slowing the mitochondrial metabolism. We examined whether rat heart contains catalysts potentially capable of reducing nitrite to NO during an episode of regional myocardial ischemia produced by temporary coronary artery occlusion. In intact Sprague-Dawley rats, a 15-min coronary occlusion lowered the nitrite concentration of the myocardial regions exhibiting ischemic glucose metabolism to approximately 50% that of nonischemic regions (185 +/- 223 vs. 420 +/- 203 nmol/l). Nitrite was rapidly repleted during subsequent reperfusion. The heart tissue tested in vitro acquired a substantial ability to consume nitrite when made hypoxic at neutral pH, and this ability was slightly enhanced by simultaneously lowering the pH to 5.5. More than 70% of this activity could be abolished by flushing the coronary circulation with crystalloid to remove trapped erythrocytes. Correspondingly, erythrocytes demonstrated the ability to reduce exogenous nitrite to NO under hypoxic conditions in vitro. In erythrocyte-free heart tissue, the nitrite consumption increased fivefold when the pH was lowered to 5.5. Approximately 40% of this pH-sensitive increase in nitrite consumption could be blocked by the xanthine oxidoreductase inhibitor allopurinol, whereas lowering the Po(2) sufficiently to desaturate myoglobin accelerated it further. We conclude that rat heart contains several factors capable of catalyzing ischemic nitrite reduction; the most potent is contained within erythrocytes and activated by hypoxia, whereas the remainder includes xanthine oxidoreductase and other pH-sensitive factors endogenous to heart tissue, including deoxymyoglobin.
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PMID:Nitrite consumption in ischemic rat heart catalyzed by distinct blood-borne and tissue factors. 1882 31