Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The paper represents a summary of our studies in which in vitro perfusion of human and animal coronary vessels was carried out. Formation and uptake of lipids in perfused human coronary arteries were studied under a vairety of experimental conditions, including exposure to carbon monoxide. The effect of collagenase on lipid synthesis and transport in carotid arteries of dogs was also studied. Human plasma with hydrogen-3-labeled cholesterol and carbon-14-acetate was used to perfuse human blood vessels. Autologous plasma was employed. Inhibition of cholesterol uptake was accomplished by the addition of 7-ketocholesterol (concentrations of 0.005 to 1 mum/ml) to the perfusate. Both atherosclerotic and normal human coronary arteries incorporated 14C-acetate into lipids but failed to synthesize either cholesterol of cholesterol esters. Similar results were obtained in human saphenous veins perfused at arterial pressure. Cholesterol uptake from the perfusion fluid was demonstrated in atherosclerotic and normal human coronary arteries as well as in human saphenous veins. Carbon monoxide increased permeability of the arterial wall to cholesterol uptake. In dog arteries exposed to collagenase marked increases in cholesterol uptake were found, but total lipid synthesis was reduced; the relative synthesis individual lipids remained unchanged. The addition of 7-ketocholesterol to the perfusate reduced cholesterol uptake by the vessel by 90 percent. Inhibition of cholesterol uptake was present in all species and was not due to oxidation of cholesterol to 7-detocholesterol in the perfusate. The results illustrate that human coronary arteries as well as human saphenous veins synthesize lipids but not cholesterol. Cholesterol flux into the artery is augmented by carbon monoxide and collagenase. The data also show that active inhibition of cholesterol uptake in the arterial wall can be accomplished by competitive inhibition with 7-ketocholesterol.
Am J Cardiol 1975 Apr
PMID:Lipid metabolism in perfused human and dog coronary arteries. 16 13

The adult newt cardiac ventricular myocyte has been successfully placed in cell culture and has been shown to undergo in vitro DNA synthesis. Although several growth factors have been reported to increase DNA synthesis in cardiac myocytes in vitro, PDGF has not been reported to do so, but has been shown to be active in other systems. Ventricles were removed from the adult red-spotted newt and were enzymatically and mechanically dissociated in a solution containing trypsin and collagenase. Cells were preplated on to plastic to remove non-myocytes. Myocytes were then plated onto laminin. Groups of myocytes were fed control medium and medium containing porcine PDGF. Myocytes were given 1 microCi/ml of tritiated thymidine 6 or 24 h before fixation. Control myocytes showed a peak DNA synthesis at 12-14 days in culture. One ng/ml of PDGF increased DNA synthesis significantly to 22% above control. Myocytes responded to PDGF with significantly increased DNA synthesis in about 12 h. PDGF did not induce earlier DNA synthesis, but increased synthesis at all days of culture tested. These results indicate that PDGF acts upon cardiac myocytes, increasing their DNA synthesis.
J Mol Cell Cardiol 1992 Sep
PMID:Stimulation of DNA synthesis by PDGF in the newt cardiac myocyte. 143 20

Hydrogen peroxide (H2O2) serves as a precursor for highly reactive oxygen intermediates. However, the respiratory function of myocytes is relatively resistant to exogenously administered H2O2. In this study, we examined whether or not the reduction of cellular defense increases the toxicity of H2O2. Rat heart myocytes were isolated by collagenase digestion. Respiratory rates of myocytes, suspended in a medium containing sucrose, 3-N-morpholino-propanesulfonic acid, EGTA and bovine serum albumin, were determined polarographically in the presence of pyruvate and malate with or without 2,4-dinitrophenol (DNP). Mitochondrial membrane potentials were measured by using [3H]triphenylmethylphosphonium+. Cellular defense was attenuated by i) inhibiting the catalase activity by 3-amino-1,2,4-triazole (AT), ii) reducing the glutathione concentration by diethyl maleate (DEM) or ethacrinic acid (EA), and iii) permeabilizing the sarcolemmal membrane by saponin. The dose-response relationship between H2O2 (0.1-5 mM) and mitochondrial membrane potential was not greatly affected by these experimental conditions. Myocyte respiration was inhibited by 5 mM H2O2, particularly that measured in the presence of DNP (48% of control). DEM treatment did not significantly affect the respiratory inhibition by H2O2, whereas the degree of inhibition was somewhat greater following EA or AT treatment. By contrast, the sensitivity of cellular respiration to H2O2 was potentiated approximately two orders of magnitude by the permeabilization of sarcolemmal membrane; thus, 100 microM H2O2 inhibited both DNP-stimulated and unstimulated respiration to 17% and 35% of control, respectively. The results indicate that factors existing in the sarcolemma and/or in the cytosol, which become ineffective and/or are diluted, respectively, following permeabilization with saponin, are important cellular defense mechanisms in alleviating the toxic effect of exogenous H2O2 on the respiration of mitochondria in situ in myocytes.
Basic Res Cardiol
PMID:Role of cellular defense against hydrogen peroxide-induced inhibition of myocyte respiration. 152 Feb 49

An investigation of myocardial glycoproteins was undertaken to elucidate the molecules responsible for the periodic acid-Schiff (PAS) reactivity of the increased extracellular matrix of diabetic cardiomyopathy. Perfusion with radiolabeled mannose indicated an enhanced formation of matrix components in the diabetic compared to the normal rat heart. Electrophoretic separation of radiolabeled extracts demonstrated the presence of glycoproteins with Mr values of 205, 142 and 90 kDa which could be separated by Bio-Gel A-5 m filtration. Fractionation of non-perfused hearts resulted in the isolation of only the 205 and 142 kDa components, which were shown by amino acid analyses and collagenase digestion to belong to the collagen family of proteins and by immunoblotting to represent type VI collagen. The carbohydrate content of these rat myocardial type VI collagen subunits, determined from monosaccharide analyses, was 11 and 12%, respectively, and N-glycanase digestion of the 142 kDa chain resulted in a decrease in size of approximately 14 kDa, indicating the presence of asparagine-linked units. Examination of normal and diabetic rat heart sections indicated that the latter contained abundant PAS-positive strands and nodules which corresponded to the distribution of anti type VI collagen reactivity. Moreover, immunoblots showed higher levels of Type VI collagen in diabetic than in normal heart extracts. Type VI collagen therefore appears to represent a major glycoprotein of myocardial extracellular matrix and to be implicated in diabetic cardiomyopathy.
J Mol Cell Cardiol 1992 Apr
PMID:Myocardial glycoproteins in diabetes: type VI collagen is a major PAS-reactive extracellular matrix protein. 161 69

Healing of myocardial infarction is associated with hypertrophy of a region surrounding the scar. In order to characterize the pattern of regional hypertrophy after healing of small myocardial infarctions, we used a Coulter Channelyzer to measure directly regional cell volume and light microscopy to measure cell length of isolated myocytes. Acute left ventricular myocardial infarctions were surgically created in adult cat hearts. After healing for 10.4 +/- 5.0 months, cells were dissociated by collagenase perfusion. Myocardial cells were isolated from three regions of the infarcted ventricle and the same three anatomical regions of unoperated control hearts: (1) remote from the infarct, (2) non-scarred tissues adjacent to the infarct, and (3) from the infarct. The volume of cells from control hearts was correlated significantly with individual body weight resulting in large inter-animal variations, but small intra-animal variations. Inter-animal comparisons were made by normalizing adjacent and infarct regions to percent change from its remote region. Myocyte volumes from hearts with healed infarcts were increased by 31% in the infarct region and by 20% in the adjacent region, relative to the corresponding regions from control hearts (P less than 0.05). Cell lengths were not different from control in any region. Calculated cross-sectional areas followed the same pattern as was observed for cell volumes. We conclude that there is a region of hypertrophy surrounding a small, transmural healed myocardial infarction that is characterized by increased myocyte cross sectional area with no change in cell length. This pattern is typical of the concentric hypertrophy observed with pressure overload rather than eccentric hypertrophy observed with volume overload.
J Mol Cell Cardiol 1991 Dec
PMID:Regional increase in isolated myocyte volume in chronic myocardial infarction in cats. 183 2

Experiments were performed to determine the cellular associations of the molecular forms of acetylcholinesterase (AChE) in adult rat heart. For this purpose, a cardiac muscle and a non-muscle fraction were isolated from rat heart ventricles after perfusion with collagenase and hyaluronidase, extracts of these fractions were subjected to ultracentrifugation on linear density gradients of sucrose (5-20%), and fractions of these gradients were analyzed for AChE activity. The results show that only globular AChE molecular forms were present in isolated cardiac muscle cells. Globular AChE forms were also present in the non-muscle cells fraction but in different proportions. The proportions of globular AChE forms plus the high specific activity of choline acetyltransferase in the non-muscle cell fraction suggest that this fraction contains cholinergic nerve fragments. The results of this study also show that asymmetric AChE is released during the perfusion of heart with the digestive enzymes, which suggests that asymmetric AChE is bound to the extracellular matrix of heart.
J Mol Cell Cardiol 1989 Oct
PMID:Acetylcholinesterase molecular forms in muscle and non-muscle cells of rat heart. 258 21

Regional changes in cardiac myocyte size and population distribution were examined in Sprague Dawley rats receiving an abdominal aortic constriction at five days of age. At specific time intervals post-constriction, hearts were recovered from constricted animals and weight-matched controls and isolated myocytes were obtained from right and left ventricles using retrograde coronary perfusion with collagenase. Cell volume and cardiac myocyte population distribution curves were determined using a Coulter Channelyzer system. Cell length was measured directly using a Bioquant Image Analysis system. Myocyte cross-sectional area was calculated from cell volume/length. By three months of age, heart weight and heart weight-body weight ratio in constricted animals had increased by approximately 115% (p less than 0.001) in females and 85% (p less than 0.001) in males compared to controls. Between 15 and 90 days of age, the growth response, as indicated by increased cell volume, was approximately 4x greater in constricted females and 2.5x greater in constricted males compared to corresponding controls. This increase was manifested by a shift in the mean size of the myocyte population to the right and a substantial widening of the distribution. Most of the enlargement was due to increased cross-sectional area, with only a moderate contribution from increased cell length. Significant increases in size were seen in both left and right ventricles. By three months of age, a significant interaction was apparent between aortic constriction and sex. The capacity for hypertrophy was greater in the smaller myocytes in female rats of similar age compared to males. The final degree of hypertrophy was similar for male and female rats, possibly indicating a critical upper limit in cell size for cardiac myocytes.
Basic Res Cardiol
PMID:Change in cardiac myocyte size distribution in aortic-constricted neonatal rats. 276 57

Large numbers of calcium-tolerant canine cardiocytes can be isolated from the collagenase-perfused canine myocardium. An average yield of 500 million cells provides abundant tissue for the preparation of subcellular fractions. Using nitrogen cavitation, along with extraction by 0.6 M potassium chloride/sucrose buffer, we have been able to prepare, after differential and sucrose gradient centrifugation, membrane fractions that are more than 100-fold enriched in sarcolemmal marker enzymes. This preparation of sarcolemma has the advantage of being essentially free of plasma membranes from endothelial, smooth muscle, and other cell types residing in the myocardium.
Basic Res Cardiol 1985
PMID:Characterization of sarcolemma from calcium-tolerant canine cardiocytes. 299 31

Myocytes were isolated by Langendorff perfusion of rat or rabbit hearts with low calcium solution followed by collagenase and hyaluronidase, or by incubation of chunks of rat ventricular tissue in similar media. Cells were then placed in a bath on a microscope stage, superfused and electrically stimulated. Contraction amplitude and rate of change of length during contraction were measured using a video camera and edge detection monitor. Cells were selected for study using a number of criteria developed to identify and define a cell population able to give consistent inotropic responses over a long period. The maximum contraction amplitude with isoproterenol in rabbit cells was 0.244 micron (sarcomere length change) or 13.1% (percentage change in cell length), and the EC50 was 12.8 nM. The maximum contraction amplitude with isoproterenol did not differ significantly between rat and rabbit, between cells prepared by perfusion and those made from chunks, or when determined from non-cumulative rather than cumulative curves. The EC50 for isoproterenol in rat cells made by the perfusion method (cumulative curves) was 3.81 nM, significantly lower than in rabbit. The maximum amplitude obtained with increasing concentrations of calcium was not significantly different from that with isoproterenol under any condition. The EC50 for calcium averaged 2.78 mM in rat cells made by the perfusion method (cumulative curves) and was significantly greater than that in rabbit (1.4 mM). Maximum rates of contraction for rat cells averaged 4.59 micron/s in 8 mM calcium. Rat cells contracted faster than they relaxed, whereas rabbit cells in 8 mM calcium relaxed faster than they contracted. Rat cells, maximally activated by either calcium or isoproterenol, contracted significantly faster than rabbit. There was no difference in rates of contraction (or relaxation) between rat cells prepared by perfusion and those made from chunks of tissue.
J Mol Cell Cardiol 1988 Jul
PMID:Contractile responses of isolated adult rat and rabbit cardiac myocytes to isoproterenol and calcium. 317 50

Regional variations in the size and shape of isolated myocytes were studied using the two-kidney, one clip (2K1C) renal model of hypertension. Weanling male Sprague-Dawley rats (50 to 75 g) were anesthetized by ketamine (100 mg/kg) during renal artery clipping (0.2 mm internal diameter silver clip) and were then allowed to grow for 6 to 8 weeks, when the blood pressure had stabilized at 180 mmHg. Hearts were removed, weighed and then were perfused with a calcium-free Joklik medium containing collagenase. Isolated myocytes were collected from five regions and fixed in isoosmolar glutaraldehyde: right ventricular free wall (RVFW), right and left halves of the interventricular septum (RIVS, LIVS), and epicardial and endocardial halves of the left ventricular free wall (LEPI, LENDO). Myocyte volume was measured by Coulter Counter. Myocyte length was measured by sonic digitizer. Cross-sectional area was calculated from myocyte volume and length. Tailcuff systolic pressure and heart weight were significantly increased in 2K1C rats as compared to control. Body weights were not different. Cell volume was significantly increased in RIVS, LIVS, LEPI, and LENDO, but not in RVFW. Cell length was not significantly increased in any region. Thus, the 2K1C model showed a predominant left ventricular hypertrophy in which the right half of the septum acted in concert with the left ventricle. The shape of the hypertrophied myocytes, having an increase in volume due to an increase in cross-sectional area but not length, was most consistent with a pressure-induced form of cardiac hypertrophy.
J Mol Cell Cardiol 1988 Nov
PMID:Regional myocyte size in two-kidney, one clip renal hypertension. 323 84


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