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

Epithelial cells from bovine colon were isolated by mechanical preparation combined with an enzymatic digestion from colon specimens derived from freshly slaughtered animals. After digestion with collagenase I, the isolated tissue was centrifuged on a 2% D-sorbitol gradient to separate epithelial crypts which were seeded in collagen I-coated culture flasks. By using colon crypts and omitting the seeding of single cells a contamination by fibroblasts was prevented. The cells proliferated under the chosen culture conditions and formed monolayer cultures which were maintained for several weeks, including subcultivation steps. A population doubling time of about 21 hr was estimated in the log phase of the corresponding growth curve. During the culture period the cells were characterized morphologically and enzymatically. By using antibodies against cytokeratine 7 and 13 the isolated cells were identified as cells of epithelial origin. Antibodies against vimentin served as negative control. Morphological features such as microvilli, desmosomes and tight junctions, which demonstrated the ability of the cultured cells to restore an epithelial like monolayer, were shown by ultrastructural investigations. The preservation of the secretory function of the cultured cells was demonstrated by mucine cytochemistry with alcian blue staining. A stable expression of enzyme activities over a period of 6 days in culture occurred for gamma-glutamyltranspeptidase, acid phosphatase and NADH-dehydrogenase activity under the chosen culture conditions. Activity of alkaline phosphatase decreased to about 50% of basal value after 6 days in culture. Preliminary estimations of the metabolic competence of these cells revealed cytochrome P450 1A1-associated EROD activity in freshly isolated cells which was stable over 5 days in cultured cells. Then activity decreased completely. This culture system with primary epithelial cells from the colon will be used further as a model for the colon epithelium in toxicological studies in vitro.
 ...
PMID:Primary cell cultures of bovine colon epithelium: isolation and cell culture of colonocytes. 1096 60

Renal proximal tubule fragments (RPT) were prepared from young-adult, male F-344 rats by deferoxamine/collagenase perfusion and evaluated as a potential model for mechanistic studies and screening, using known nephrotoxins. Chloroform and S-(1,2- dichlorovinyl )- l - cysteine (DCVC) produced depressed O(2) consumption rates (basal and/or nystatin-stimulated) and lactate dehydrogenase (LDH) release during 8-hr incubations at 0.5 mg RPT protein/ml. Cytochrome P-450 inhibitors piperonyl butoxide and metyrapone were either without effect or potentiated chloroform-induced toxicity. DCVC was more cytotoxic to RPT than to rat hepatocytes. The cytotoxic potency for cephalothin relative to cefazolin decreased as RPT content in the medium was increased to 3.0 mg protein/ml, giving a rank order more in accord with results reported in vivo. Cephalosporins markedly depressed brush border alkaline phosphatase (ALP) activity, without affecting gamma-glutamyltranspeptidase activity; the effect on ALP was less sensitive to the RPT level. Acetaminophen (25 mm) and p-aminophenol (1.0 mm) induced LDH release without ALP depression and inhibited mitochondrial respiration. These results in general corresponded well with in vivo responses and indicate that this RPT system may be valuable for studies of chemical-induced nephrotoxicity.
 ...
PMID:Studies of nephrotoxic agents in an improved renal proximal tubule system. 2070 4

Isolated human primary hepatocytes are an essential in vitro model for basic and clinical research. For successful application as a model, isolated hepatocytes need to have a good viability and be available in sufficient yield. Therefore, this study aims to identify donor characteristics, intra-operative factors, tissue processing and cell isolation parameters that affect the viability and yield of human hepatocytes. Remnant liver pieces from tissue designated as surgical waste were collected from 1034 donors with informed consent. Human hepatocytes were isolated by a two-step collagenase perfusion technique with modifications and hepatocyte yield and viability were subsequently determined. The accompanying patient data was collected and entered into a database. Univariate analyses found that the viability and the yield of hepatocytes were affected by many of the variables examined. Multivariate analyses were then carried out to confirm the factors that have a significant relationship with the viability and the yield. It was found that the viability of hepatocytes was significantly decreased by the presence of fibrosis, liver fat and with increasing gamma-glutamyltranspeptidase activity and bilirubin content. Yield was significantly decreased by the presence of liver fat, septal fibrosis, with increasing aspartate aminotransferase activity, cold ischemia times and weight of perfused liver. However, yield was significantly increased by chemotherapy treatment. In conclusion, this study determined the variables that have a significant effect on the viability and the yield of isolated human hepatocytes. These variables have been used to generate an algorithm that can calculate projected viability and yield of isolated human hepatocytes. In this way, projected viability can be determined even before isolation of hepatocytes, so that donors that result in high viability and yield can be identified. Further, if the viability and yield of the isolated hepatocytes is lower than expected, this will highlight a methodological problem that can be addressed.
...
PMID:An algorithm that predicts the viability and the yield of human hepatocytes isolated from remnant liver pieces obtained from liver resections. 2531 81


<< Previous 1 2