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)

Phospholipase C has been studied in homogenates, total particulate and soluble fractions of horse and human platelets. This enzyme, assayed with exogenous L-3-phosphatidyl[14C]inositol, is predominantly localized in the soluble fraction and its distribution parallels that of lactate dehydrogenase. A small percentage of activity present in the particulate fraction seems to be due to contamination with soluble enzyme. Enzyme from horse and human platelets appears identical, having a Km of 0.10-0.15 mM, acid pH optimum (pH 5.5) and showing Ca2+-dependency and weak inhibition by deoxycholate. Analysis of the reaction products shows the formation of myo-inositol 1,2-cyclic phosphate and myo-inositol 1-phosphate in almost equal amounts. Platelet stimulation with thrombin does not seem to induce association of the cytosolic activity to the membranes. The cytosolic activity is not affected by pretreatment of the intact platelets with prostacyclin or thrombin. Degradation of phosphatidylinositol present in a membrane fraction isolated from platelets by cytosolic phospholipase C requires addition of deoxycholate. Our information suggests that the degradation of phosphatidylinositol in stimulated platelets is mainly achieved by exposure of the substrate to the cytosolic enzyme and by an increase of the free Ca2+ concentration needed for optimal phospholipase C activity.
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PMID:Properties and distribution of phosphatidylinositol-specific phospholipase C in human and horse platelets. 686 Jul 6

Lactate and pyruvate of perilymph (PL) were studied 30, 60, and 120 min postmortem. During this period the mean lactate concentration of scala tympani and scala vestibuli increased from 4.8 mmol/l found intravitally to 17.8 and 15.1 mmol/l, respectively, whereas pyruvate decreased from an average of 0.33 to 0.10 mmol/l (fig. 1). These inverse changes of concentration yield postmortem lactate/pyruvate quotients which are more than one order of magnitude higher than the quotients found intravitally (Table 1). In comparative tests of blood samples carried out 30, 60, and 120 min after the sampling (Fig.1), the lactate increase was found to be markedly lower than in postmortem PL. The substantial metabolite changes in PL seem to be caused by glycolytic activity of all cochlear structures that are in direct contact with PL. The decrease of pyruvate level is probably due to a shift of the lactate-pyruvate equilibrium (lactate dehydrogenase system) in PL. The blood vessels in the perilymphatic space can be neglected as postmortem metabolite source of PL.
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PMID:[Postmortem changes in the perilymphatic lactate and pyruvate concentrations of guinea pigs. (author's transl)]. 697 14

Suspensions of enzymatically prepared hepatocytes from starved rats were separated according to their buoyant density at 12 degrees C in linear, isosmotic gradients of metrizamide, centrofuged at low speed for a relatively short time. The recovery of cell protein was 86%. Hepatocytes of high viability formed a single band around 1.10 g/cm3 and were recovered as four density populations (P1-P4) form low to high density, respectively. The content of protein was significantly lower in population P1, while the content of neutral fat or the averaged cell size was similar in the various populations. The specific activity of alanine aminotransferase increased in the order P1-P4. The distribution of this enzyme within the intact liver acinus obtained by others indicate that a partial separation of periportal and perivenous hepatocytes had occurred. The activity patterns of lactate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase (NADP+) and pyruvate kinase, also with known intra acinar distributions, supported this conclusion. The hepatocytes showed signs of shrinkage after separation, but since they retained a normal ultrastructure, most enzyme activities and viability, the present technique was regarded superior to previous procedures of hepatocyte separation by density. The degree of separation was calculated from an equation (see Appendix), and the periportal/perivenous ratio for parameters measured in density populations can be obtained. The specific activity of phosphofructokinase, alcohol dehydrogenase and aldehyde dehydrogenase showed no differences between populations. However, the ratio high-Km/low-Km aldehyde dehydrogenase increased in the order P4-P1.
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PMID:Partial separation and biochemical characteristics of periportal and perivenous hepatocytes from rat liver. 702 82

The activity of lactate dehydrogenase from the cattle myocardium extract as well as of this enzyme crystalline form was studied in the presence of structural analogues of the nicotinamide fragment NAD-amide, diethyl amide and N-oxymethyl amide of nicotinic acid. It is shown that the rate of the reaction catalyzed with lactate dehydrogenase under the effect of amide and N-oxymethyl amide of nicotinic acid decreases to a different extent depending on their concentration. Nicotinic diethyl amide practically has no effect on the activity of lactate dehydrogenase. Ki for crystalline lactate dehydrogenase and myocardium lactate dehydrogenase in the presence of nicotinic amide is 0.23.10-3 and 1.13.10-3 M. respectively, in the presence of nicotinic N-oxymethyl amide-0.30.10-3 and 0.10.10-3 M.
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PMID:[Lactate dehydrogenase activity in the presence of certain structural analogs of the nicotinamide fragment of NAD]. 705 48

Phase invariant signature algorithm (PISA), a new noninvasive technique, was used in the detection and quantification of acid-induced myocardial damage in anesthetized dogs. The diagnostic capabilities of this method were compared with those of conventional electrocardiogram and biochemical markers, MB-creatine phosphokinase (MB-CPK) and lactic dehydrogenase (LDH1). Myocardial damage of varying degree was induced by injecting diluted sulphuric acid (0.01 to 0.10 ml) into the free wall of the left ventricle. Conventional ECG, wideband ECG for PISA analysis, blood samples for LDH1, and MB-CPK were taken before and after 15, 30, 60, and 90 min of acid injection. The heart was removed at the end of 90 min for estimation of myocardial damage. PISA Index increased within 10-15 min of acid injection and remained elevated for the duration of the experiment (90 min). The increase in the PISA index was directly related to the extent of myocardial damage and the amount of acid injected. Although the conventional electrocardiogram detected large myocardial damage, it was unable to detect small myocardial damage. Also, most of initial change in conventional ECG with large myocardial damage disappeared within 90 min, while the PISA index was still elevated to the maximum level. The MB-CPK was not detected before or after myocardial damage. There was no significant change in the LDH1 at any time after myocardial infarction. These results suggest that the PISA technique is superior to the conventional ECG and the biochemical markers and would be a valuable diagnostic tool in the detection and quantification of incipient as well as advanced myocardial infarction.
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PMID:PISA: a noninvasive method in detection and quantification of acid-induced myocardial infarction in dogs. 727 1

Analytical subcellular fractionation techniques using metrizamide density gradients have been used to investigate the properties of the gut hormone storage granules and the principal organelles from homogenates of normal human jejunal mucosa obtained by peroral mucosal biopsy. The individual hormones, detected by radioimmunoassay, each showed single discrete peaks in the density gradient experiments indicating localisation to single granules each with characteristic modal densities. Thus motilin showed a modal density of 1.15, gastrin 1.16, gastric inhibitory polypeptide (GIP) 1.17, enteroglucagon 1.18 and somatostatin and vasoactive intestinal peptide (VIP) 1.10 g/ml. The following organelles, characterised by their marker enzymes were located in the density gradients; plasma membrane (5'-nucleotidase) brush border (alpha-glucosidase, pH 6.0) mitochondria (particulate malate dehydrogenase), peroxisomes (catalase), lysosomes (N-acetyl-beta-glucosaminidase), endoplasmic reticulum (alpha-glucosidase, pH 8.0), cytosol (lactate dehydrogenase). These studies provide biochemical evidence of the distinct nature of the individual gut hormone storage granules and provide a basis for studying dynamic changes in the granules in response to physiological stimuli and pathological processes.
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PMID:Characterisation of gut hormone storage granules from normal human jejunum using metrizamide density gradients. 730 92

To examine the effects of acute exposure to fumonisin-containing culture material (FCCM), 15 crossbred wether lambs were dosed intraruminally with FCCM containing 0 (CONTROL, n = 3), 11.1 (LOW, n = 4), 22.2 (MED, n = 4), or 45.5 (HIGH, n = 4) mg of total fumonisins (B1, B2, and B3)/kg BW daily for 4 d. Blood samples were collected daily, and on d 11 lambs were killed and necropsied. Changes in serum constituents in fumonisin-treated lambs indicative of liver damage, included increased (P < .05) activities of alkaline phosphatase, gamma-glutamyl transferase, aspartate aminotransferase, and lactate dehydrogenase. Serum concentrations of cholesterol, triglycerides, urea nitrogen, and creatinine were also increased (P < .05) in lambs dosed with FCCM. Hemoglobin tended to increase (P = .07) and white blood cell count tended to decrease (P = .08) in HIGH lambs and activated partial thromboplastin time tended to decrease (P < .10) in lambs dosed with LOW and MED treatments. Mitogen-induced lymphocyte blastogenesis was not different (P = .14) among treatments. Feed intake markedly decreased (P < .01) following the first dosing of FCCM and continued to decline throughout the study. Ruminal VFA concentrations and pH tended to decrease (P < .10) at d 11 in treated lambs. Relative liver and kidney weights (g/100 g of BW) increased (P < .05) in fumonisin-treated lambs. Histiolgical examination revealved tubular nephrosis and mild hepatopathy in dosed lambs. Lambs receiving the HIGH treatment died on d 3, 4, 5, and 7 of the study and on d 9 one lamb on the MED treatment died.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acute hepatic and renal toxicity in lambs dosed with fumonisin-containing culture material. 760 85

This study was designed to investigate the possible involvement of the thromboxane A2 (TXA2)-TXA2 receptor (TXA2R) system of the hepatic sinusoid in cold preservation/reperfusion injury in liver grafts. Rat livers were preserved in cold University of Wisconsin solution for either 6 or 24 hr. The number of TXA2Rs in sinusoidal endothelial cells isolated from 0-, 6-, and 24-hr preserved liver specimens was 22.50 +/- 1.80 x 10(3)/cell, 12.66 +/- 1.00 x 10(3)/cell, and 4.17 +/- 0.65 x 10(3)/cell, respectively. Kd and Bmax at 0 hr, 6 hr, and 24 hr of preservation were 8.54 +/- 1.26 nM and 37.34 +/- 3.01 fmol/10(6) cells, 7.08 +/- 1.14 nM and 12.66 +/- 1.00 fmol/10(6) cells, and 1.91 +/- 0.10 nM and 3.88 +/- 0.59 fmol/10(6) cells, respectively. The administration of OKY-046 (inhibitor of TXA2 synthesis) to the University of Wisconsin solution suppressed this reduction in TXA2R number. Furthermore, the concentration of TXA2 in hepatic sinusoid was decreased by OKY-046. In a reperfusion experiment, liver tissue preserved for 24 hr exhibited a higher reperfusion pressure, and effluent levels of both aspartate aminotransferase and lactate dehydrogenase were markedly elevated. The addition of OKY-046 to the preservation solution, however, prevented the rise in reperfusion pressure almost completely and the increase in effluent enzyme levels. This study showed that the TXA2Rs in sinusoidal endothelial cells were internalized through binding with TXA2 during cold preservation, causing activation of the TXA2-TXA2R system. This activation apparently induces an increase in reperfusion pressure, possibly due to sinusoidal contraction, resulting in microcirculatory disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Involvement of thromboxane A2-thromboxane A2 receptor system of the hepatic sinusoid in pathogenesis of cold preservation/reperfusion injury in the rat liver graft. 770 55

The present study was undertaken to assess the effect of carvedilol, a new vasodilating beta-adrenoceptor blocker with antioxidant activity, on the oxidation of low-density lipoproteins (LDL) by rat aortic smooth muscle cells (RASMC). LDL oxidation was assessed as thiobarbituric acid reactive substances (TBARS) formation and increase in electrophoretic mobility. Oxidized (ox) LDL-induced cytotoxicity was assessed as lactate dehydrogenase release (LDH) from cells and ox-LDL-enhanced adhesiveness of the RASMC for leukocytes was also determined. Carvedilol inhibited TBARS formation and LDH release from RASMC with IC50 values of 1.74 and 1.62 microM, respectively. Under the same conditions, the IC50 values of probucol and nicardipine were 2.33 and 5.60 microM, respectively, for inhibition of TBARS and 5.16 and 12.10 microM, respectively, for inhibition of LDH release; propranolol, atenolol, pindolol and labetalol, at concentrations up to 100 microM, had virtually no effect on either variable. RASMC-dependent ox-LDL stimulated the adhesive properties of RASMC for both monocytes and neutrophils in a concentration- and time-dependent manner, which were prevented when the RASMC were treated with carvedilol (IC50 2.07 microM for monocytes and 1.12 microM for neutrophils), whereas other beta blockers, at concentrations up to 30 microM, had only mild effects. The monoclonal antirat intercellular adhesion molecule-1 antibody partially inhibited ox-LDL-induced adhesion of RASMC for monocytes and neutrophils. Northern analysis demonstrated that ox-LDL induced intracellular adhesion molecule-1 messenger RNA expression on RASMC, which was inhibited by carvedilol and probucol via inhibition of LDL oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Carvedilol, a new vasodilating beta-adrenoceptor blocker, inhibits oxidation of low-density lipoproteins by vascular smooth muscle cells and prevents leukocyte adhesion to smooth muscle cells. 779 Nov 19

A high resolution electrophoretic method has been developed to separate plasma high density lipoprotein (HDL) particles by size using 4-30% polyacrylamide agarose (PAA) gradient gels, Sudan black B staining, and laser densitometry. Fourteen distinct HDL bands were observed with HDL-1 being designated as the largest particle and HDL-14 as the smallest particle. HDL-1 was similar in size to ferritin (Stokes diameter 12.2 nm), HDL-8 to catalase (9.2 nm), and HDL-13 to lactate dehydrogenase (8.1 nm). HDL-1 to HDL-7 were found within the density range of HDL2b (d 1.063-1.10 g/ml), HDL-8 to HDL-10 within HDL2a (d 1.10-1.125 g/ml), and HDL-11 to HDL-14 within HDL3 (d 1.125-1.21 g/ml). On immunoblotting, apolipoprotein A-I (apoA-I) was found in all HDL bands examined, being most prominent in HDL-6, 11, and 12. ApoA-II was not detected in HDL bands 1-5, but was present in all other HDL bands and was most prominent in HDL-9. ApoE was detected mainly in HDL bands 1-7, and was observed in only trace amounts in other bands. Lp A-I isolated by immunoaffinity column chromatography from the plasma of five subjects contained five subspecies (HDL-5, 6, and 11-13), while Lp A-I/A-II also had five subspecies (HDL-8, 9, and 11-13) in these subjects. In normal subjects (n = 57) four or five HDL bands were generally observed, with HDL-9, 11, and 12 being the most frequently observed. Mean HDL particle score (method of sizing based on scanning densitometry, where low score indicates large size and high score indicates small size) was significantly correlated (P < 0.001) with the concentrations of HDL cholesterol (r = -0.796), HDL free cholesterol (r = -0.780), HDL cholesteryl ester (r = -0.683), HDL phospholipid (r = -0.663), HDL apoA-I (r = -0.577), and HDL protein (r = -0.459), but not with HDL triglyceride (r = 0.069). In addition, HDL particle score was significantly correlated (P < 0.05) with HDL total mass (r = -0.649), HDL free cholesterol content (% of total mass, r = -0.608), HDL triglyceride content (r = 0.415), HDL phospholipid content (r = -0.359), and HDL protein content (r = 0.295), but not with HDL cholesteryl ester content (r = -0.219) or HDL apoA-I content (r = 0.183).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Analysis of high density lipoproteins by a modified gradient gel electrophoresis method. 780 82


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