Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: C33C12 .10
63,145 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat liver parenchymal cell binding, uptake, and proteolytic degradation of rat 125I-labeled high density lipoprotein (HDL) subfraction, HDL3 (1.10 less than d less than 1.210 g/ml), in which apo-A-I is the major polypeptide, were investigated. Structural and metabolic integrity of the isolated cells was verified by trypan blue exclusion, low lactic dehydrogenase leakage, expected morphology, and gluconeogenesis from lactate and pyruvate. 125I-labeled HDL3 was incubated with 10 X 10(6) cells at 37 degrees and 4 degrees in albumin and Krebs-Henseleit bicarbonate buffer, pH 7.4. Binding and uptake were determined by radioactivity in washed cells. Proteolytic degradation was determined by trichloroacetic acid-soluble radioactivity in the incubation medium. At 37 degrees, maximum HDL3 binding (Bmax) and uptake occurred at 30 min with a Bmax of 31 ng/mg dry weight of cells. The apparent dissociation constant of the HDL3 receptor system (Kd) was 60 X 10(-8) M, based on Mr = 28,000 of apo-A-I, the predominant rat HDL3 protein. Proteolytic degradation showed a 15-min lag and then constant proteolysis. After 2 hours 5.8% of incubated 125I-labeled HDL3 was degraded. Sixty per cent of cell radioactivity at 37 degrees was trypsin-releasable. At 37 degrees, 125I-labeled HDL3 was incubated with cells in the presence of varying concentrations of native (cold) HDL3, very low density lipoproteins, and low density lipoproteins. Incubation with native HDL3 resulted in greatest inhibition of 125I-labeled HDL3 binding, uptake, and proteolytic degradation. When 125I-labeled HDL3 was preincubated with increasing amounts of HDL3 antiserum, binding and uptake by cells were decreased to complete inhibition. Cell binding, uptake, and proteolytic degradation of 125I-labeled HDL3 were markedly diminished at 4 degrees. Less than 1 mM chloroquine enhanced 125I-labeled HDL3 proteolysis but at 5 mM or greater, chloroquine inhibited proteolysis with 125I-labeled HDL3 accumulation in cells. L-[U-14C]Lysine-labeled HDL3 was bound, taken up, and degraded by cells as effectively as 125I-labeled HDL3. These data suggest that liver cell binding, uptake, and proteolytic degradation of rat HDL3 are actively performed and linked in the sequence:binding, then uptake, and finally proteolytic degradation. Furthermore, there may be a specific HDL3 (lipoprotein A) receptor of recognition site(s) on the plasma membrane. Finally, our data further support our previous reports of the important role of liver lysosomes in proteolytic degradation of HDL3.
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PMID:Rat high density lipoprotein subfraction (HDL3) uptake and catabolism by isolated rat liver parenchymal cells. 18 84

The rate constants for inactivation of lactate dehydrogenase and alcohol dehydrogenase in solution at 65 degrees C (pH 7,5) are 0,72 and 0,013 min-1, respectively. The enzyme incorporation into acrylamide gels results in immobilized enzymes, whose residual activity is 18--25% of the original one. In 6,7% gels the rate of thermal inactivation for lactate dehydrogenase is decreased nearly 10-fold, whereas the inactivation rate for alcohol dehydrogenase is increased 4,6-fold as compared to the soluble enzymes. In 14% and 40% gels the inactivation constants for lactate dehydrogenase are 6,3.10(-3) and 5,9.10(-4) min-1, respectively. In 60% gels the thermal inactivation of lactate dehydrogenase is decelerated 3600-fold as compared to the native enzyme. The enthalpy and enthropy for the inactivation of the native enzyme are equal to 62,8 kcal/mole and 116,9 cal/(mole.grad.) for the native enzyme and those of gel-incorporated (6,7%) enzyme -- 38,7 kcal/mole and 42 cal/(mole.grad.), respectively. The thermal stability of alcohol dehydrogenase in 60% gels is increased 12-fold. To prevent gel swelling, methacrylic acid and allylamine were added to the matrix, with subsequent treatment by dicyclohexylcarbodiimide. The enzyme activity of the modified gels is 2,7--3% of that for the 6,7% gels. The stability of lactate dehydrogenase in such gels is significantly increased. A mechanism of stabilization of the subunit enzymes in highly concentrated gels is discussed.
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PMID:[Thermal stability of lactate dehydrogenase and alcohol dehydrogenase incorporated into highly concentrated gels]. 46 89

Fourteen patients with severe viral illnesses were given intravenous infusions of a modified interferon inducer, polyriboinosinic-polyribocytidylic acid-poly-L-lysine complexed with carboxymethylcellulose [poly)I:C.LC)], during a phase 1 clinical trial. The first eight patients received 0.15 to 0.30 mg of poly(I:C.LC) per kg of body weight daily for 5 consecutive days, and another received two courses separated by 1 week. A second group of five patients was given single intravenous infusions of 0.10 to 0.15 mg of poly(I:C.LC) per kg. Interferon was detectable in the serum 8 to 16 h after injection. Titers ranged from 15 to 800 U/ml and varied directly with the dose of poly(I:C.LC). Interferonemias persisted for 12 to 48 h. In patients receiving 5-day courses of poly(I:C.LC), lower levels of serum interferon (0 to 160 U/ml) occurred on days 2 through 5, characteristic of a hyporesponsive state. An exception was a 69-year-old patient with disseminated varicella zoster, multiple myeloma, and renal insufficiency whose serum contained 3,150 U of interferon per ml on day 3 of 0.3 mg of poly(I:C.LC) per kg. Fever (39 to 40.5 degrees C, rectally; 13 of the 14 patients) peaked 3 to 8 h after completion of infusions. Other toxic effects included lymphopenia (10 of the 14 patients), hypotensive episodes (7 of the 14 patients), and minor elevations of serum glutamicoxalacetic transaminase and lactic dehydrogenase.
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PMID:Modified polyriboinosinic-polyribocytidylic acid complex: sustained interferonemia and its physiological associates in humans. 50 Jan 89

Low concentrations of a polyoxyethylene detergent, Brij 58, inhibited the secondary phase of platelet aggregation induced by ADP in human citrated platelet-rich plasma but had no effect on primary aggregation. Thrombin-induced aggregation of washed human platelets suspended in Tyrode's buffer was inhibited after incubation of cells with 4.10(-6) M detergent. Efflux of [14C]serotonin, 45Ca2+ and labile aorta contracting substance (thromboxane A2) and development of prothrombin-converting activity (platelet factor 3) were abolished concomitantly. Aggregation of washed platelets either by sodium arachidonate or by collagen was also inhibited by the same concentration of Brij 58 which inhibited thrombin aggregation. This concentration did not itself produce any release of a cytoplasmic marker, lactate dehydrogenase, from platelets. Higher concentrations of Brij 58, exceeding 4.10(-5) M, lysed the cells liberating lactate dehydrogenase, serotonin and Ca2+. When albumin was included as a platelet stabilizer in the suspending medium the concentration of detergent required for the inhibitory effects was increased ten-fold. This could be attributed to competitive binding of the detergent to albumin, demonstrated with [14C]acetylated Brij 58. A variety of other polyoxyethylene detergents, at concentrations from 8.10(-4) to 5.10(-3) M, also inhibited platelet aggregation induced by thrombin. It is concluded that low concentrations of Brij 58 stabilize the platelets against the action of aggregating agents, while higher concentrations produce membrane destabilization and cell lysis.
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PMID:Effects of a polyoxyethylene detergent (Brij 58) on platelet aggregation, release and clotting activity. 62 96

Analytical, intra-individual, and inter-individual components of variance were estimated in 10 volunteers for 34 assays encompassing 22 different constituents. Replicate blood specimens were obtained four times weekly. Nine constituents were measured with more than one instrument [Technicon AutoAnalyzer II and SMAC System, Perkin-Elmer Kinetic Enzyme Analyzer KA-150, and (or) the Abbott Bichromatic Aanalyzer ABA-100]. For those constituents that were stored for randomized batch analysis, results were examined for evidence of changes during storage and within-run analytical drift. Alkaline phosphatase, cholesterol, dopamine-beta-hydroxylase, and SMAC-measured lactate dehydrogenase had a ratio of intra-individual to interindividual variance of less than 0.10, thus exhibiting a high individuality. This ratio was greater than one for sodium, carbon dioxide, and creatine kinase. Analytical variance was more than 30% of total variance for sodium, carbon dioxide, calcium, total protein, and chloride. Analytical variance was less than 20% of intra-individual variance for bilirubin, creatine kinase, KA-150-measured lactate dehydrogenase, triglycerides, and urea nitrogen. Limits for the expected difference between measurements of the same constituent for the same individual on different days are also presented.
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PMID:Variance components of serum constituents in healthy individuals. 62 51

Seven enzymes of the Embden-Myerhof pathway of glycolysis were assayed in hypotonically treated epididymal sperm from mature rabbits. These were: fructose-biphosphate aldolase, triosephosphate isomerase, glyceraldehydephosphate dehydrogenase, 3-phosphoglyceromutase, enolase, pyruvate kinase, and lactate dehydrogenase. These enzymes were firmly enough bound to the cell structure to resist removal by washing after hypotonic treatment and had maximal activities comparable to, or greater than, the rate of mitochondrial pyruvate oxidation, so that rapid oxygen uptake was observed with intermediates of the glycolytic pathway. The activity of lactate dehydrogenase in a typical preparation of hypotonically treated cells was 5.3 mumoles/minute x 10(9) cells at 25 degrees C for pyruvate reduction in the hypotonically treated cells and 4.8 mumoles/minute x 10(9) cells in the thrice-washed hypotonically treated cells. The Km for pyruvate was 1.4 mM while that for lactate was 4.4 mM. By contrast, the maximal activity of pyruvate oxidation by mitochondria was 0.10 microgram atom of oxygen/minute x 10(9) cells, corresponding to 0.020 mumole of pyruvate/minute x 10(9) cells, and the Km for pyruvate was 5 microM. These enzyme parameters favor high lactate production from glucose in aerobic glycolysis.
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PMID:Energy metabolism of spermatozoa. V. The Embden-Myerhof pathway of glycolysis: activities of pathway enzymes in hypotonically treated rabbit epididymal spermatozoa. 80 42

Properties of lactate dehydrogenase (LDH) in the eye, heart and muscles of Hemigrapsus sanguineus, Paralithodes camtschatica, Erimacrus isenbeckii, Pandalus latirastrus, Pagurus brachiomastus have been studied with acrylamide gel electrophoresis and kinetics analysis. LDH in all the tissues of all the representatives studied was found to be specific for L-pyruvate and lactate; it migrated in electrophoresis as a single band revealing low mobility towards anode. The isoenzyme from P. camtschatica and P. latirastrus differed from the isoenzymes of other animals studied by higher mobility towards anode that reflected higher negative value of its total charge. The LDH isoenzymes in all the animals studied resembled the A4 (LDH5) of the vertebrates being unstable to the denaturing action of high temperature and being unaffected by high concentrations of pyruvate up to 1.0.10-3M. On the other hand, in conrast to the A4 of mammals, the LDH in question displayed enhancement of the reaction rate and decrease of the Km values upon increase in the NAD+ and NAD.H concentrations both in the presence of high or low lactate and pyruvate concentrations. The isoenzymes displayed catalytic activity also in the presence of NADP, the Km values for pyruvate in the presence of equimolar (2.25 mM) concentrations of NAD.H or NADP.H were practically identical and were found to be within the limits of 14-26.10-5 M. Molecular weight of the LDH studied assessed by the gel filtration method was found to be 130-140,000. It is suggested that the LDH isoenzyme from the representatives of the decapod crayfish studied is homologous in its certain properties to the homotetrameric A4 form of the vertebrates.
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PMID:[Lactate dehydrogenase isoenzymes in the eye, cardiac and skeletal muscles of several decapods]. 102 May 51

The purpose of our study was to investigate the interrelationship of known and possible new risk factors in patients with metastatic neuroblastoma and to define groups at risk. The possible influence of 37 variables on event-free survival (EFS) was analyzed univariately in 308 consecutive patients using the Kaplan-Meier estimate. Fifteen factors were identified (p less than 0.05, logrank greater than 3.84) of whom eight showed a nonrandom correlation to several others (chi 2-test, p less than 0.05). Seven noncorrelated factors [lactate dehydrogenase (LDH) level, resectability of the primary tumor, histologic grade, leukopenia, presence of symptoms, general condition, and age at diagnosis] were included in the multivariate analysis of 182 patients according to the Cox model. The variables LDH (p = 0.0007), resectability (p = 0.0063), histologic grade (p = 0.0055), and leukopenia (p = 0.0470) were identified multivariately as prognostic factors for EFS. These results permitted the classification of patients into three prognostic groups. The 6 year event-free survival for group IV-A (LDH normal) was 0.37 +/- 0.12, for group IV-B (LDH abnormal, additional risk factors favorable) 0.18 +/- 0.10, and for group IV-C (LDH abnormal, 1-3 additional risk factors unfavorable) was 0.08 +/- 0.03. We conclude that the proposed clinicopathological classification may prove to be a reliable and easily applicable tool for estimating the outcome of metastatic neuroblastoma in children.
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PMID:Prognostic factors in metastatic neuroblastoma. A multivariate analysis of 182 cases. 151 Jan 89

This trial was carried out to evaluate the therapeutic benefit of the addition of mitomycin to vindesine plus cisplatin (80 mg/m2) in 126 previously untreated non-small cell lung cancer (NSCLC) patients. 124 patients were evaluable for toxicity and survival and 122 for response. No patient achieved complete response. The partial response rate (PR) in the vindesine plus cisplatin (VP) and mitomycin plus vindesine and cisplatin (MVP) groups were 23% (14/62) vs. 35% (21/60) (P = 0.13) with a median duration of response of 23 vs. 37 weeks (P = 0.071), respectively. Time to progression (TTP) and survival time (ST) were similar for both treatment arms [median TTP; 14 vs. 21 weeks (P = 0.10), median ST; 9.1 vs. 10.5 months (P = 0.94), respectively]. No difference in the frequency of side-effects was observed except that WHO grade 3 and 4 leukopenia was higher in the MVP group. In multivariate analysis, the significant predictors of survival were serum albumin, sex, performance status, lactate dehydrogenase and stage. In conclusion, the addition of mitomycin to the VP regimen appears to have limited value in advanced NSCLC.
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PMID:A randomised clinical trial of vindesine plus cisplatin versus mitomycin plus vindesine and cisplatin in advanced non-small cell lung cancer. 164 83

Neutrophils migrate to areas of inflammation and, when stimulated, produce O2-, H2O2, and other reactive O2 metabolites. To assess the effects of stimulated neutrophils on enterocytes, rat enterocytes were incubated with peripheral neutrophils. To assess cell viability, trypan blue exclusion and lactate dehydrogenase and protein release were measured. When 10(6) enterocytes/mL were incubated with 2.5 x 10(5) neutrophils/mL stimulated with phorbol myristate acetate, trypan blue exclusion decreased and lactate dehydrogenase and protein release increased. With the addition of 0.10 mg/mL of superoxide dismutase, trypan blue exclusion further decreased and lactate dehydrogenase and protein release increased. This suggests that H2O2- or H2O2/O2(-)-derived metabolites are more damaging to isolated enterocytes than O2-. To test this hypothesis, enterocytes were incubated with xanthine and increasing concentrations of xanthine oxidase in the presence and absence of superoxide dismutase. With increasing concentrations of xanthine oxidase, the cell number decreased and protein release increased. With the addition of superoxide dismutase, fewer cells were present, suggesting that cell lysis occurred. Protein release was further increased by the addition of superoxide dismutase. Enterocytes were then incubated with leucine and increasing concentrations of amino acid oxidase. With increasing concentrations of amino acid oxidase, trypan blue exclusion decreased and protein and lactate dehydrogenase release increased. These effects were ameliorated by the addition of 500 IU catalase/mL. These data suggest that O2- and H2O2, whether created by stimulated neutrophils or an enzyme-generating system, are damaging to isolated enterocytes. Superoxide dismutase did not offer enterocytes protection.
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PMID:Rat enterocyte injury by oxygen-dependent processes. 165 Mar 18


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