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)

22 human pancreases were removed soon after circulatory arrest from donors aged 15--63 years. Part of the pancreas was used for isolation of islets by the collagenase technique. The mean yield +/- SEM, expressed as the number of islets isolated from 4 g pancreas was 79 +/- 15. The yield varied considerably even when the pancreas was removed immediately after circulatory arrest and the histology was normal, and there was no correlation with the age of the donors. The islet content of insulin (ng/microgram dry islet) was 8.5 +/- 1.2 (mean +/- SEM). Isolated islets were loaded with 45Ca in the presence of 20 mM glucose and placed in a perfusion apparatus for further studies of the 45Ca washout. The decrease of washout of radioactivity in Ca2+-deficient medium offers support for the existence of a Ca2+-Ca2+ exchange process. When added in a concentration of 20 mM, glucose tended to stimulate 45Ca efflux in perfusion medium of ordinary ionic composition but inhibited this process when the medium was deficient in Ca2+. Exposure to the calcium ionophore X-537A resulted in immediate stimulation of of 45Ca efflux from human islets as previously observed for islets from rats and mice. This suggests that Ca2+ has a direct regulatory role for insulin release also in humans.
 ...
PMID:Collagenase isolation and 45Ca efflux studies of human islets of Langerhans. 21 85

A procedure for dissociating the rabbit aorta into single, functional smooth muscle cells is described. After removal of adventitia and intima, slices of media were incubated with purified collagenase, elastase, and soybean trypsin inhibitor in a Krebs-Ringer buffer modified with Hepes, amino acids, and a [Ca2+] of 0.2 mM. After enzymatic digestion and mechanical shear, the yield of dispersed cells was approximately 25% based on DNA recovered. Greater than 95% of the cells excluded trypan blue and approximately 80-90% adhered to tissue culture dishes. By phase contrast microscopy, most of the cells were elongate and approximately 10 micron X 30 micron in size. The remainder were either spherical or highly crenated and contracted. Electron microscopy of the cells showed that immediately after dissociation greater than 95% could be identified as smooth muscle, though most had undergone some degree of structural change compared to cells in situ. Depending on the preparation, from 5 to 50% of these cells contracted in response to agonists. Cells shortened by 10-15% and developed numerous evaginations when stimulated by angiotensin II norepinephrine, or carbamylcholine. Cells relaxed after washout of agonists and could subsequently be restimulated. Specific inhibitors of each of the agonists blocked the contractile response. Dispersed cells cultured for 1-5 days contracted in even higher numbers than the freshly prepared cells, suggesting restoration of hormone binding and/or contractile function in culture. This preparation provides a system in which the physiology of individual vascular smooth muscle cells may be studied.
 ...
PMID:Preparation of functional smooth muscle cells from the rabbit aorta. 21 9

Isolated pancreatic acini were prepared by a new method from mouse and rat pancreases by digestion with purified collagenase and chymotrypsin followed by mechanical shearing. Acini were structurally similar to those of the intact pancreas, having a normal luminal structure but with the basal acinar cell membranes exposed to the incubation medium. Amylase release in response to both cholinergic analogues and the cholecystokinin analogues caerulein and pentagastrin was comparable to that of the intact pancreas, but was much greater than previously reported for isolated acinar cells. Cholinergic-stimulated release was inhibited by atropine with a Ki value of 1.4 nM which is comparable to other muscarinic receptors. All agonists tested, when added at supramaximal concentrations, produced a submaximal release of amylase even though ATP levels and the release of slowly exchanging 45Ca2+ were normal or increased. Acini releasing amylase submaximally after being exposed to supramaximal concentrations of carbachol failed to respond to a maximal amount of caerulein or to the Ca2+ ionophore A23187. It is concluded that the decreased response (desensitization) is a postreceptor phenomenon and possibly mediated by Ca2+ itself.
 ...
PMID:Action of secretagogues on a new preparation of functionally intact, isolated pancreatic acini. 21 42

A bone morphogenetic protein (BMP) obtained in solution by digestion of demineralized rabbit cortical bone matrix with bacterial collagenase retains its biologically active conformation in a neutral salt/ethylene glycol mixture. BMP may be insolubilized by coprecipitation with calcium phosphate and resolubilized by chemical extraction with a neutral salt in the same solvent mixture. Upon concanavalin A-Sepharose chromatography, BMP is bound by hydrophobic interaction and carbohydrate recognition and is recovered by elution with either alpha-methyl mannoside or ethylene glycol solvent mixture. Implants of both eluates and the extracts of the coprecipitate in double-walled diffusion chambers induce transmembrane bone morphogenesis. BMP is not species specific; rabbit BMP induces new bone formation in the rat. The present observations indicate that BMP is a glycoprotein.
 ...
PMID:Solubilized and insolubilized bone morphogenetic protein. 22 8

It was shown previously that addition of cyclic AMP (cAMP) to a synaptic membrane fraction incubated with [gamma-32P]ATP stimulated the phosphorylation of two proteins, designated proteins Ia and Ib, found only in nerve tissue. Addition of Ca2+ plus veratridine to synaptosomes preincubated with 32Pi stimulated the phosphorylation of two proteins with similar apparent molecular weights. Various techniques have now been used to determine whether the two proteins phosphorylated in synaptosomes in the presence of Ca2+ plus veratridine are the same as proteins Ia and Ib phosphorylated in synaptic membranes in the presence of cAMP. The proteins phosphorylated by the two procedures were extracted under similar conditions, had similar apparent molecular weights and charges, and were digested by collagenase at similar rates and to the same radioactive intermediates and end products. Furthermore, the two sets of proteins were digested by three other proteolytic enzymes to phosphopeptides with similar molecular weights. The results indicate that Ca2+ and cAMP are each capable of regulating the phosphorylation of proteins Ia and Ib.
 ...
PMID:Ca2+ and cyclic AMP regulate phosphorylation of same two membrane-associated proteins specific to nerve tissue. 22 28

Isolation of preneoplastic cell populations would greatly facilitate analysis of the development of liver carcinogenesis. Suspensions of intact single cells can be prepared in an almost quantitative yield by two-step perfusion of the isolated liver. In the first step the liver is perfused with a Ca2+-free buffer (or with EGTA) in order to irreversibly cleave the desmosomes; in the second step perfusion with Ca2+-activated collagenase dissolves the collagenous extracellular matrix. The resulting single-cell suspension will be a mixture of intact normal and preneoplastic hepatocytes, other liver cell types (mostly Kupffer and endothelial cells), damaged cells, and subcellular debris. Intact hepatocytes can be purified--e.g., by differential centrifugation--but separation of preneoplastic from normal cells has not yet been achieved. Density gradient separation or selection in culture on the basis of the unique properties of preneoplastic hepatocytes (e.g., drug resistance) may prove useful. The use of hepatocyte cultures and liver-derived epithelial cell lines as test systems and models for chemical carcinogenesis in vitro is briefly reviewed.
 ...
PMID:Hepatocyte suspensions and cultures as tools in experimental carcinogenesis. 22 9

The extracellular release from human neutrophils of the primary (azurophil) granule constituents, myeloperoxidase (MPO), chymotrypsin-like cationic protein (CCP), collagenase and lysozyme, and the secondary (specific) granule constituents, lactoferrin and lysozyme, was measured during ingestion of staphylococcus protein-A-IgG complexes. In buffer, lactoferrin release was consistently higher than that of the other protein. In serum, lactoferrin release increased concomitantly with ingestion, whereas the rate of lysozyme and especially of MPO release were stimulated to a higher degree than ingestion. Magnesium (0.5--2 mM) was more potent than calcium (0.5--2 mM) in promoting release but these cations worked synergistically. Zinc (0.5--4 mM) was found to be a potent and selective inhibitor of collagenase release. Manganese (0.25--4 mM), which inhibited the ingestion of SpA-IgG complexes, also inhibited release of CCP, collagenase, lysozyme and MPO, but actually stimulated lactoferrin release. The data suggests that lactoferrin and lysozyme may be confined to distinct granule populations or else released in a different fashion from the granules. When the effects on release of primary granule proteins are concerned it is suggested that the dissociation of binding of various agents to an anionic granule matrix may be affected differently by various cations.
 ...
PMID:Effects of serum and cations on the selective release of granular proteins from human netrophils during phagocytosis. 22 47

An enzymatic procedure for the isolation of metabolically active tumour cells from human renal cell carcinoma is described. The cells were suspended by a multistep incubation procedure of the tissue in the presence of collagenase (10 mg enzyme/g tumour wet weight) dissolved in a calcium-free buffer solution. About 90% of the isolated tumour cells were viable, as judged by routine trypan blue staining. Electron microscopic examination revealed tumour cells in various stages of dedifferentiation. The cells had retained their capability of protein synthesis. In short term experiments the effects of 17 beta-oestradiol and progesterone on the incorporation of [U - C] L-leucine into cellular proteins was studied; Progesterone was found to exhibit a slight tumour antianabolic or catabolic action. A 17 beta-oestradiol-dependent modulation of the rates of protein synthesis was not observed.
 ...
PMID:[Viable cells from human renal cell carcinoma: isolation procedure and analysis of hormone sensitivity (author's transl)]. 22 52

Bovine adrenal chromaffin cells were isolated by removal of the cortex and sequential collagenase digestion of the medulla. The catecholamine secretory function of these cells was characterized with respect to acetylcholine stimulation, cation requirements, and cytoskeletal elements. The dose-response curve for stimulated release had its half-maximum value at 10(-5) M acetylcholine, and maximum secretion was on the average 7 times that of control basal secretion. The differential release of epinephrine versus norepinephrine after stimulation with 0.1 mM acetylcholine occurred in proportion to their distribution in the cell suspension. The cholinergic receptors were found to be predominantly nicotinic. The kinetics of catecholamine release were rapid, with significant secretion occurring in less than 60 sec and 85% of maximum secretion within 5 min. A critical requirement for calcium in the extracellular medium was demonstrated, and 80% of maximum secretion was achieved at physiologic calcium concentrations. Stimulation by excess potassium (65 mM KCl) also induced catecholamine secretion which differed from acetylcholine stimulation in being less potent, in having a different dependence on calcium concentration, and in its response to the local anesthetic tetracaine. Tetracaine, which is thought to inhibit membrane cation permeability, was able to block acetylcholine-stimulated but not KCl-stimulated secretion. The microtubule disrupting agent vinblastine was able to block catecholamine release whereas the microfilament disrupter cytochalasin B had little effect. The results show the isolated bovine chromaffin cells to be viable, functioning, and available in large quantity. These cells now provide an excellent system for studying cell surface regulation of hormone and neurotransmitter release.
 ...
PMID:Stimulus-secretion coupling in chromaffin cells isolated from bovine adrenal medulla. 27 Jul 38

Viable suspensions of human colonic mucosal lymphoid cells have been prepared by sequential treatment of tissue with dithiothreitol, EDTA in calcium- and magnesium-free salt solutions, and purified collagenase. The intestinal lymphocyte population, in comparison with that of peripheral blood, had greater numbers of bone marrow-derived cells, particularly cells bearing membrane IgA; showed spontaneous association with macrophages; underwent rapid rosette formation with sheep erythrocytes; and demonstrated increased in vitro synthesis of immunoglobulin. Total thymus-derived cells were equal in the two populations. Decreases were found in "null" cell numbers, in cells bearing membrane IgD and IgM, and in responsiveness to phytohemagglutinin. Macrophage/monocytes in the intestinal population were increased in size, granularity, motility, sustained glass adherence, and phagocytic activity. Human intestinal lymphoid cells appear to constitute a cell population that is more "mature" and/or "activated", in comparison with the lymphoid cells of peripheral blood. The method of preparation should lend itself to the study of inflammatory bowel disease, gastrointestinal cancer, and the intestinal secretory immune system.
 ...
PMID:Isolation and functional characterization of human intestinal mucosal lymphoid cells. 32 91


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>