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)

Neuroepithelial bodies (NEB) in 29-day fetal rabbit lung were examined by light microscopy and cytochemistry to demonstrate their structural and biochemical properties in situ. Longitudinal sections of NEB at airway bifurcations demonstrated their chemoreceptor-like appearance. Furthermore, the cytochemical presence of serotonin, acetylcholinesterase, formaldehyde-induced fluorescence, and silver-staining properties demonstrated the neural-like biochemical properties of NEB cells. Forty-one NEB and eight single neuroendocrine cells from whole fetal lungs were examined ultrastructurally. Juxtaluminal junctional complexes composed of tight and intermediate junctions, desmosomes, and cytoplasmic filaments were demonstrated in the corpuscular-shaped NEB. Basal bodies were apparent in NEB cell cytoplasm; cilia extended from NEB cells. Dense-core vesicles (DCV) were of at least three types: type 1, type 2, and enterochromaffin type. The majority of epithelial cells adjacent to NEB in near-term airway epithelium were undifferentiated, with large amounts of glycogen. However, ciliated cells were adjacent to some small NEB and single neuroendocrine cells; mucus or Clara-type cells were not observed. NEB isolated by collagenase treatment revealed an intact organoid structure, DCV, and desmosomes and retained their argyrophilia and formaldehyde-induced fluorescence. NEB were recovered in cell fractions separated by unit gravity that had cells in clumps of four or more. One to five NEB stained with silver in cytocentrifuge preparations of control, mixed cells, whereas up to 20 intact NEB were demonstrated in the clump-containing, separated fractions. We propose that isolated NEB retain certain biochemical and metabolic properties similar to those of their counterparts in situ. Serotonin and 5-hydroxyindole acetic acid were found by high-performance liquid chromatography analysis in the fractions containing NEB, and amine precursor uptake and decarboxylation (APUD) activity were demonstrated. Moreover, muscarinic cholinergic receptors were detected, consistent with the occurrence of acetylcholinesterase in NEB. The elution profile of bombesin radioimmunoactivity substantiated that isolated fetal rabbit NEB contained this neuropeptide and that NEB were enriched by unit gravity sedimentation. These studies suggest that NEB are structurally and functionally developed before other cell types in immature airway epithelium and can be isolated as intact organoids, which retain some of their structural and metabolic integrity.
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PMID:Morphological and cytochemical characterization of neuroepithelial bodies in fetal rabbit lung. I. Studies of isolated neuroepithelial bodies. 613 13

Rat pancreatic acini were prepared with collagenase A and collagenase P and their secretory response to carbachol tested. The collagenase P gave the best acinar suspension, providing that the digestion was performed in the absence of added calcium and in the presence of a low concentration of albumin. More than ninety percent of the acini prepared with this crude collagenase were viable as judged by a coloration with eosine. Their basal amylase secretion was below 3% amylase released within 20 minutes. They responded to cholecystokinin (7-fold stimulation, EC50: 10 pM), to bombesin (7-fold stimulation, EC50: 1 nM), to carbachol (7-fold stimulation, EC50: 1 microM), to fluoroaluminate (4-fold stimulation, EC50: 3 mM) or to TPA (4-fold stimulation, EC50: 100 nM). Acini preloaded with fura2 and incubated in the presence of 0.5 mM extracellular calcium were able to maintain a large (5,000-fold) gradient of calcium across their plasma membrane. Carbachol, CCK-8 and bombesin increased the intracellular calcium concentration 6-fold, within 10 seconds. This level decreased for the next 20 seconds but remained higher than the basal value for the next 10 minutes. These acini could be permeabilized with a low concentration (0.1 U/ml) of streptolysin O without affecting the basal amylase secretion, an index of the integrity of zymogen granules. It is concluded that pancreatic acini which have retained their responsiveness to major pancreatic secretagogues can be prepared with crude collagenase and permeabilized with streptolysin O. They can thus be used as a model for the study of stimulus-secretion coupling in exocrine glands.
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PMID:Isolation of rat pancreatic acini with crude collagenase and permeabilization of these acini with streptolysin O. 767 14

We describe, for the first time, the development of a technique for a long-term selective culture of endocrine (PE) cells from the lungs of normal animals. Epithelial cells were isolated from 1-day-old hamster lungs through mechanical and enzymatic dissociation with collagenase type II. Cells were then cultured in HITES medium which contained RPMI 1640, hydrocortisone, insulin, transferrin, estradiol, sodium selenite, and supplemented with 5% fetal bovine serum (FBS), or medium which contained HITES medium supplemented with bovine serum albumin, phosphoethanolamine, arginine vasopressin, bombesin, and 2% FBS (9N). HITES medium, originally developed for establishment and long-term culture of human small cell lung cancer (SCLC) cell lines, allowed propagation of normal hamster PE cells up to 12 months as a mixed floating-attached cell culture. No difference was noted in the results using HITES or 9N. By 3 months, 80% of the cultured cells contained characteristic dense-core (endocrine type) granules. The cultured PE cells also expressed creatine kinase brain isoenzyme, and general NE markers including neuron specific enolase, and amine handling enzyme activity within the range of SCLC cell lines. Moreover, cultured PE cells contained and secreted immunoreactive calcitonin (iCT) which had a molecular profile similar to that of intact hamster lung. This long-term culture technique should markedly assist in elucidating the role of PE cells in health and disease.
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PMID:Long-term selective culture of hamster pulmonary endocrine cells. 838 31

In the present study we have characterized receptor-mediated Ca2+ signalling patterns as well as Ca(2+)-mediated ion transport mechanisms in collagenase isolated rat pancreatic acini. Measurements of the initial Ca2+ response to maximal carbachol stimulation revealed a rapid increase in [Ca2+]i, which, in general, occurred synchronously throughout the cells. Less frequently, not all cells in the acinus responded to carbachol, but did respond to subsequent stimulation with bombesin, indicating that not all cells possess receptors for all the applied agonists. In view of the heterogeneity in the agonist-evoked Ca2+ responses, ionomycin was used to assess the role of Ca2+ in activating K+, Na+ and Cl- transport mechanisms, Ionomycin induced a rise in [Ca2+]i, thereby increasing Cl- permeability as well as stimulating K+ efflux, probably through non-specific cation channels. However, the resting K+ efflux was insensitive to blockers of non-specific cation channels, indicating the existence of a selective resting K+ conductance. Ionomycin also stimulated influx of Na+, which in part was mediated by non-specific cation channels. The changes in ion fluxes measured in the present study revealed that when [Ca2+]i is raised in rat pancreatic acini, they gain Na+ and Cl- and lose K+, with non-specific cation channels being essential for this process.
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PMID:Stimulation-induced calcium signalling and ion transport in rat pancreatic acini. 912 72

Gastric infection with Helicobacter pylori is associated with hypergastrinemia. Platelet activating factor (PAF) is produced in H. pylori-infected mucosa. The effects of PAF on gastrin release from cultured antral rabbit G cells were examined. Rabbit antral G-cells were obtained by collagenase-EDTA digestion and enriched by centrifugal elutriation. After 40 hr in culture, gastrin release in response to PAF was assessed. PAF stimulated gastrin release in a dose-dependent manner. A maximal release of 67% above basal was seen with PAF at 100 nM. PAF also enhanced the gastrin release stimulated by forskolin and bombesin. PAF-stimulated gastrin release was abolished by a PAF-receptor antagonist. Gastrin release stimulated by PAF was abolished by chelation of intra- or extracellular calcium or the L-type calcium channel inhibitor verapamil as well as by the protein kinase C inhibitor chelerythrine. Platelet-activating factor may contribute to the hypergastrinemia of H. pylori infection by stimulating gastrin release from G cells. PAF-stimulated gastrin release involves influx of extracellular calcium via L-type channels and activation of protein kinase C.
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PMID:Effect of platelet-activating factor on gastrin release from cultured rabbit G-cells. 1128 66


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