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 basement membrane of the human umbilical vein was studied by electron microscopy with respect to its ultrastructure, susceptibility to digestion by collagenase or trypsin, and reactivity with human platelets. Electron microscopic examination of this vessel showed a continuous reticulated basement membrane which morphologically resembled those of mammalian capillaries and rabbit heart valves. The vascular endothelium was removed by freezing and thawing, thus uncovering the underlying connective tissue. The vessels were sliced into rings which were incubated with collagenase or trypsin. The basement lamella appeared to be susceptible to digestion by either enzyme. Platelet interaction with exposed vascular basement mambrane was studied by rotating frozen-thawed everted and noneverted rings in anticoagulated whole human blood. In heparinized or citrated blood, large aggregates of degranulated platelets adhered to collagenous controls; in contrast, the test rings with exposed basement membrane were partially covered with a monolayer of platelets which appeared to retain discoid or spherical shape and granules. In EDTA-anticoagulated blood, the collagen control rings accumulated a platelet monolayer, whereas little or no adhesion occurred on the basement membrane surface. In this system the basement membrane of the human umbilical vein appears to be a poor platelet reactive surface as compared to collagen.
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PMID:Platelet interaction with human umbilical cord vascular basement membrane. 18 62

Clostridium perfringens produces a variety of virulence factors. The mechanism of action of these factors usually falls into one of three groups. Some of these virulence factors, such as the alpha toxin, which is phospholipase C, and the kappa toxin, which is a collagenase, are enzymes that hydrolyze substances essential to the integrity of membranes or other body structures. Other virulence factors, such as the beta, episolon, and iota toxins, act primarily on the vascular endothelium, causing increased capillary permeability, especially in the brain. Still others, such as the delta and theta toxins, are essentially hemolysins. Theta toxin is similar in action and serologically related to streptolysin O.
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PMID:Virulence factors of Clostridium perfringens. 23 35

Cellular migration and replication were studied during repair of mechanical injuries produced in cultured monolayers of vascular endothelium. Human endothelial cells were obtained by collagenase perfusion of term umbilical cord veins and were grown on glass cover slips in replicate primary cultures. Following standardized mechanical denudation ("wounding") of narrow linear areas in postconfluent cultures, cellular migration and DNA synthesis were assessed at intervals after terminal 3H-thymidine incubation. Migration of cells from the edges of the wound into the denuded area was consistently underway by 12 hours, and by 24 hours there was considerable repopulation of the wound. A significant increase in 3H-thymidine labeling was not observed in the wound area until 36 hours. When cultures were exposed to 1500 rads of x-rays 1 hour prior to wounding, labeling was nearly abolished at 48 and 72 hours despite continuous incubation with 3H-thymidine. However, migration occurred as usual and resulted in repopulation similar to that in nonirradiated replicate cultures. These studies indicate that small endothelial defects can be significantly repaired by migration of adjacent viable cells. Thus, factors influencing both migration and replication should be considered in studies dealing with endothelial regeneration in vivo.
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PMID:Cellular migration and replication in endothelial regeneration: a study using irradiated endothelial cultures. 83 Sep 92

The efficiency of Eurocollins or modified University of Wisconsin (UW) solution (MUW) in preserving rat livers was compared. After cold storage with one of the solutions, the livers were transplanted or perfused by collagenase for isolation of hepatocytes. Five of the 6 rats receiving a graft preserved with MUW versus none of the 6 rat receiving a graft preserved with Eurocollins solution survived 24 h or more. A significantly greater number of hepatocytes were isolated from livers preserved with MUW than from livers preserved with Eurocollins solution. This suggests a better reperfusion of MUW-preserved livers by collagenase resulting from less endothelial injury. LDH release by cultured hepatocytes, ketone body production and stimulation by glucagon were not significantly different between the two groups. These results confirm the superiority of MUW solution over Eurocollins in preserving liver grafts. They suggest that the advantage of MUW solution results from better protection of vascular endothelium rather than of hepatocytes.
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PMID:Comparison of rat liver preservation with Eurocollins and a modified University of Wisconsin solution: transplantation and isolation of hepatocytes for culture. 207 86

These studies were designed to determine the role of cerebral vascular endothelium in the "myogenic" depolarization and contraction observed in isolated cat middle cerebral arteries exposed to high transmural pressures. With intact endothelial cells we observed, on elevation of transmural pressure in cannulated isolated arteries, significant membrane depolarization, action potential generation, and reduction in internal diameter. After perfusion of the same vessels with collagenase and elastase for short periods of time to disrupt the endothelial layer, all previous responses to elevation of transmural pressure were no longer seen. Even though enzyme perfusion had no effect on membrane potential at "control" levels of transmural pressure, it abolished the pressure-dependent depolarization, action potential generation, and constriction. Furthermore, the contractile response to agonist stimulation was maintained after endothelial disruption via enzymes, showing that this method of endothelial disruption did not appreciably damage muscle cells. The data document a dependence of an intact endothelium in mediating the activation of isolated cat cerebral arteries in response to a changing transmural pressure. Thus, it is possible that the endothelial cell may serve as a transducer in the autoregulatory response to pressure.
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PMID:Pressure-induced myogenic activation of cat cerebral arteries is dependent on intact endothelium. 356 82

Capillaries isolated by collagenase digestion of hamster epididymal fat pads were used to examine the properties of endothelial adenylate cyclase and cyclic nucleotide phosphodiesterase. Adenylate cyclase activity in capillary homogenates was increased by 10 microM GTP or 100 microM isoproterenol. Lower concentrations of the catecholamine and 5.7 microM prostaglandin E1 did not stimulate endothelial adenylate cyclase activity unless GTP was included in the assay system. The effects of isoproterenol on capillary adenylate cyclase activity were blocked by propranolol, but were not affected by phentolamine. Phosphodiesterase activity in endothelial homogenates showed anomalous kinetic behavior with either cyclic AMP or cyclic GMP as the enzyme substrate. At substrate concentrations below 1 microM, capillary phosphodiesterase activity hydrolyzed cyclic GMP 2-6 times faster than cyclic AMP. However, at high substrate levels, e.g., 100 microM, cyclic AMP and cyclic GMP were degraded at similar rates. Hydrolysis of 1 microM cyclic AMP by capillary homogenates was stimulated by 0.1 and 1 microM cyclic GMP. Caffeine, 1-methyl-3-isobutylxanthine, papaverine and dipyridamole SQ 20009 were effective inhibitors of capillary phosphodiesterase activity. In contrast, imidazole enhanced the activity of the enzyme. The presence of adenylate cyclase and phosphodiesterase activities in hamster isolated capillaries is consistent with a role for cyclic AMP in the regulation of endothelial function. Moreover, the experiments described here indicate that hamster isolated capillaries are useful model systems for studying the metabolism of vascular endothelium.
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PMID:Properties of adenylate cyclase and cyclic nucleotide phosphodiesterase in hamster isolated capillary preparations. 624 1

Microvascular endothelial cells play an important part in inflammation as well as in organ specific leucocyte traffic, and may be functionally different from large vessel endothelium in this respect. This study therefore established a method for isolation and longterm culture of human intestinal microvascular endothelial cells (HIMEC). After dissociation by collagenase/dispase/DNase of mucosal and submucosal tissue obtained from normal adult jejunum, cells were plated and cultured to subconfluence in endothelial serum free medium containing 2.5% fetal calf serum, hydrocortisone, and N6, O2-dibutyryladenosine cyclic monophosphate. Primary cultures were trypsinised and endothelial cells were isolated by paramagnetic beads armed with monoclonal antibody to CD31. Optimal growth conditions for HIMEC cultures were established, allowing up to nine passages (three months in vitro). The cells contained Weibel-Palade bodies, expressed von Willebrand factor, CD31, and VE-cadherin; and bound Ulex Europaeus lectin I. A method to establish longterm cell cultures of HIMEC will facilitate further investigation of the function of intestinal endothelial cells and their participation in physiological and pathological events in the gut.
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PMID:Isolation and longterm culture of human intestinal microvascular endothelial cells. 755 73

Endothelial cells were derived from aortic and mitral valves (n = 17) by collagenase digestion and subsequently cultivated in RPMI medium supplemented with 20% fetal calf serum. The cells were stained in an alkaline phosphatase-anti-alkaline phosphatase stain for the expression of MHC Class I and Class II antigens, ICAM-1, ELAM-1, F VIII, and H/Y. The endothelium showed a strong expression of Class I, H/Y, and ICAM-1 molecules, and weak expression of MHC Class II molecules. In contrast to vascular endothelium that is known to express F VIII constitutively, cardiac valve endothelium was found to be negative. F VIII and ELAM-1 were only expressed after stimulation with recombinant interferon-gamma. To analyze the immunogenicity of valve endothelium, cells were used as stimulator cells in a mixed cell culture reaction using lymphocytes as responder cells. Endothelial cells had a 2 to 3 times higher stimulatory effect than peripheral blood lymphocytes. These data allow speculation on whether the observed degeneration of homografts can be reduced if HLA matching is performed prior to valve implantation.
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PMID:In vitro cultivation and immunogenicity of human cardiac valve endothelium. 828 71

Tumor invasion and metastasis are complex phenomena believed to be facilitated by the disruption of collagen and elastin fibers in the extracellular matrix. Interstitial collagenase gene expression was studied in colonic adenocarcinoma and adenoma using in situ hybridization. The data indicated that three cell types within the tumor stroma expressed collagenase transcripts; they were eosinophils, fibroblasts, and vascular endothelium. In all 12 adenocarcinomas, a high to moderate level of expression was seen in 1 to 5% of eosinophils and in occasional fibroblasts, whereas these cell types in non-neoplastic mucosa adjacent to tumor showed no detectable expression. Two adenocarcinomas showed expression in hyperplastic endothelium in vascularized granulation tissue. Two out of three adenomas showed expression in eosinophils and fibroblasts at a reduced level. Tissue inhibitor of metalloproteinase-1 gene expression was, however, negligible in all tissue examined. These results suggest that interstitial collagenase gene activation in the tumor stroma, especially eosinophils, may have an important role in tumor invasion and metastasis.
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PMID:Interstitial collagenase gene expression in colonic neoplasia. 836 69

The vascular endothelium normally is maintained in a quiescent state, but under certain conditions it is induced to undergo marked changes in behavior and form new vascular structures. A complex interaction among various growth and differentiation factors and the extracellular milieu regulates this behavior. One series of signals affecting endothelial behavior is provided by laminin, a major structural protein of basement membrane. These signals have been studied using Matrigel, a reconstituted basement membrane preparation from the murine Englebreth-Holm-Swarm sarcoma, in an in vitro assay of endothelial cell differentiation. Three biologically-active sequences from the laminin molecule have been evaluated. Synthetic peptides that include the sequences -RGD-, -YIGSR-, and -SIKVAV- mediate, respectively, cell binding to Matrigel, alterations in cell morphology, and induction of migration and collagenase activity. Preliminary data indicate that observations made with this system may be relevant to endothelial function in vivo. Endothelial cell differentiation on Matrigel may thus be a useful in vitro model for the study of certain steps in angiogenesis.
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PMID:Role of laminin in endothelial cell recognition and differentiation. 843 60


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