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)

In many countries, including Brazil, extracts of Jatrophona elliptica species are currently used for the treatment of several diseases. Recently it was shown that a purified compound from these plants inhibits contraction of smooth and cardiac muscle in the microM range, probably involving alterations in membrane Ca2+ permeability and/or internal Ca2+ distribution. In collagenase-isolated rat islets and in the absence of glucose, basal insulin secretion measured by radioimmunoassay averaged 122 +/- 13 microU/islet per 90 min (N = 25). At 16.7 mM glucose, the insulin output reached 445 +/- 32 microU/islet per 90 min (N = 27). Jatrophone (1-100 microM/l) caused a dose-related inhibition of glucose-induced insulin release, over basal secretion, with an ID50 close to 8 microM/l. Complete inhibition of insulin release was obtained with 100 microM/l Jatrophone. However, at 100 microM/l (but not at 10 microM/l) concentration, Jatrophone also provoked a reduction in glucose metabolism by the islets which could explain, at least in part, the reduction in insulin secretion. After 120-min incubation, the glucose metabolism, measured by the 14CO2 production, was reduced from 26.58 +/- 3.63 (N = 42) to 7.48 +/- 1.36 (N = 16) pmol/l per islet. In conclusion, at lower concentrations (10 microM/l) Jatrophone could be a valuable tool for the study of the mechanism of insulin release induced either by glucose or other secretagogues.
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PMID:Inhibition of insulin release by Jatrophone. 134 26

A new type of bioartificial liver using isolated hepatocytes immobilized in alginate beads was developed and its capacity of correcting the metabolic deficiency of bilirubin conjugation in Gunn rats was assessed. Hepatocytes were isolated from Sprague-Dawley rats using the in situ collagenase perfusion technique, and they were then immobilized in Calcium alginate beads. The capacity of these immobilized hepatocytes to conjugate in vitro bilirubin was checked as compared to monolayer hepatocyte culture. The bioartificial liver consisted in a cylindrical bioreactor containing either alginate beads and hepatocytes (test group), or only alginate beads (control group). Gunn rats were connected to this bioreactor through and extracorporeal circulation system, and "bile samples were collected" every hour. Bilirubin mono and biconjugates were dosed in the bile using the high-performance liquid chromatography technique. The viability of alginate immobilized hepatocytes, determined before and after each experiment, was stable at 75%. In the test group, the total conjugate concentration rapidly increased to reach a maximum value of 204 +/- 16 microns after 3 hours, while in the control group, there were only conjugate traces (1 micron). These results show that the bioartificial liver is an efficient means to temporarily correct genetic deficiency in Gunn rats. Such a system could be of therapeutic interest in case of acute hepatic insufficiency.
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PMID:[Extracorporeal bio-artificial liver using isolated hepatocytes. An experimental study in the rat]. 134 2

Adult, canine intervertebral disc cells were isolated with a sequential digestion of pronase and bacterial collagenase. The nonchondrodystrophoid nucleus pulposus exhibits two populations of cells: large notochordal cells and smaller chondrocyte-like cells. The cells from the transition zone and anulus fibrosus are uniform in size, ranging from 17 to 21 microns. The isolated cells were encapsulated in alginate beads and cultured in Ham's F-12 medium containing 5% heat-inactivated fetal bovine serum. Alginate bead formation requires calcium ions and can be reversed with a suitable chelator, thus releasing viable cells. We observed that 58% of the newly synthesized proteoglycans formed large-molecular-weight aggregates with hyaluronic acid. The proteoglycans contained low amounts of keratan sulfate (KS) (less than 5% of the total glycosaminoglycans synthesized). The chondroitin sulfates (CS) consisted of 51-67% as 6-O-sulfate and 29-39% as 4-O-sulfate, with the remainder (4-10%) present as 4,6-sulfate for all three zones of the disc. The majority of cells synthesized significant amounts of matrix as evidenced by Alcian Blue staining. By immunohistochemical analysis, the matrix contained chondroitin 6-sulfate as demonstrated by monoclonal antibodies to the unsaturated disaccharides remaining on the proteoglycan core after chondroitinase ABC digestion. Keratan sulfate was also present in the majority of the matrices around cells. These results emphasize the similarity of the newly synthesized proteoglycans secreted by cells grown in alginate beads to those synthesized by the neonate disc. These experiments also demonstrate the usefulness of this method as a microculture technique for disc cells.
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PMID:Initial characterization of the metabolism of intervertebral disc cells encapsulated in microspheres. 138 73

The function of nasal polyp mast cells has not been elucidated despite the large number of these cells observed in tissues. We examined these mast cells histochemically, immunohistologically and functionally. Ninety-three percent of collagenase dispersed cells in a nasal polyp were formalin-sensitive. These dispersed cells released histamine in reaction to calcium ionophore A23187 in a dose dependent manner, but not in response to C5a, Compound 48/80 or Substance P. From these results, dispersed mast cells from nasal polyps were considered to be analogous to dispersed mast cells from the human lung and nasal mucosa but not those from human skin. On the other hand, in the reaction with anti-human IgE, dispersed mast cells from a non allergic nasal polyp could not be seen to release histamine. In only 2 of 7 patients, could histamine release in response to Japanese red cedar antigen, from mast cells sensitized passively with the serum of Japanese red cedar pollinosis, seen. Using small tissue samples from polyps, histamine was released by anti-human IgE in allergic patients but not in non allergic patients. Immunohistologically in allergic nasal polyps, some IgE positive mast cells could be seen, whereas in non allergic polyps these cells were absent. These observations suggest that mast cells which had accumulated in nasal polyps both with and without allergy were capable of functional histamine release, whereas in the nasal polyps of allergy patients but not in non-allergic patients these cells are involved in IgE mediated reactions.
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PMID:[Studies on the function of mast cells infiltrating in nasal polyps]. 138 Sep 84

Enhanced contractile responsiveness to the calcium channel agonist Bay K 8644 has been documented in large conduit arteries and small muscular arteries from hypertensive rats. The present study examined the effects of Bay K 8644 on the intracellular calcium concentration ([Ca2+]i) in microvessels from stroke-prone spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. Using microspectrofluorometry of fura-2, [Ca2+]i was measured in smooth muscle cells localized on arteriolar fragments (15-35 microns external diameter) isolated after collagenase digestion of the pancreas. Resting [Ca2+]i in hypertensive arterioles (94 +/- 6 nM, n = 29) did not differ from that in normotensive vessels (81 +/- 4 nM, n = 40). KCl (50 mM), applied alone and in the presence of Bay K 8644 (30 nM), stimulated increases in [Ca2+]i that were reversed in calcium-free solution and with nifedipine (10 microM), consistent with activation of potential-operated calcium channels. Potassium-induced calcium transients were consistently potentiated by Bay K 8644. The change in [Ca2+]i evoked by KCl alone or in combination with Bay K 8644 did not differ between arterioles from hypertensive and normotensive rats. In 24% of the vessels from hypertensive rats and in 29% of those from normotensive rats, Bay K 8644 evoked an increase in [Ca2+]i that did not differ significantly between the two strains. The findings indicate that, in contrast to observations made in larger arteries, there is no evidence of a functional abnormality in potential-operated calcium channels in very small arterioles from genetically hypertensive rats.
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PMID:Calcium channel activation in arterioles from genetically hypertensive rats. 138 37

Calcium-dependent conformational changes of surfactant protein A (SP-A) and the collagenase resistant fragment (CRF) of SP-A were studied by measuring fluorescence spectra. The emission peaks of both SP-A and CRF in the absence of Ca2+ appeared at 343 nm when they were excited at 280 nm. In the presence of Ca2+, the peaks appeared at 340 nm and were accompanied by an increase in the fluorescence intensity. The magnitude of the fluorescence intensity change induced by Ca2+ was amplified by the addition of dithiothreitol (DTT) in both SP-A and CRF. The Ca2+ binding of CRF was measured by a flow dialysis method with 45CaCl2 in the Ca2+ concentration range where the Ca(2+)-induced fluorescence changes occurred. The maximum binding number of Ca2+ to CRF was about 2 mol per mol of CRF, and the value was independent of the presence of DTT.
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PMID:Calcium dependent conformational changes of surfactant protein A (SP-A) and its collagenase resistant fragment with or without dithiothreitol. 139 Sep 20

Potassium (K+)-induced norepinephrine (NE) release was examined in preparations of cardiac synaptosomes and sliced atria from 6-, 24-, and 26-mo-old male F344 rats. Cardiac synaptosomes were prepared from rat hearts by collagenase digestion followed by homogenization in 0.32 M sucrose and centrifugation. The synaptosome preparations and the sliced atria were labeled with 3H-NE and then placed in a superfusion system. K(+)-induced net fractional release of NE from synaptosomes prepared from 24- and 26-mo-old rats (4.3% and 3.0%, respectively) was significantly reduced when compared to NE release from synaptosomes from 6-mo-old rats (5.2%). K(+)-induced NE release from sliced atria from 24-mo-old rats (4.7%) was also significantly reduced when compared to NE release from atria from 6-mo-old rats (6.3%). Perfusion of cardiac synaptosomes with buffer prepared without calcium (CA++free, < 5 microM) reduced K(+)-induced release by 50% in all age groups studied. Perfusion with tyramine induced identical rates of NE release from cardiac synaptosomes prepared from 6- and 24-mo-old rats. These results confirm that depolarization-induced NE release from cardiac sympathetic nerves is reduced in the old male F344 rat.
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PMID:Effect of age on potassium- and tyramine-induced release of norepinephrine from cardiac synaptosomes in male F344 rats. 143 Aug 47

To evaluate whether treatment with a mitogenic agent may increase bone formation and bone mass in osteopenia induced by estrogen deficiency, we determined the effect of oral fluoride treatment on bone and bone cells in ovariectomized rats. Sodium fluoride (NaF) was administered to 3-month-old ovariectomized rats 1 day after ovariectomy (OVX) for 1, 3, and 6 months. NaF was given in drinking water at the dose of 1 mg/kg body weight per day. Fluoride administration led to a partial prevention of the bone loss induced by OVX as shown by histologic analysis of tibial metaphysis and by evaluation of femoral calcium content. These beneficial effects of fluoride were more striking at early time points (1 and 3 months postovariectomy) than after 6 months of treatment. The increase in trabecular bone volume in OVX rats treated with fluoride was associated with a rise in the osteoblast surface, which was increased by 60, 72, and 235% at 1, 3, and 6 months postovariectomy compared to untreated OVX rats. In OVX rats and in sham-operated rats plasma osteocalcin was increased in correlation with the osteoblast surface. However, these two parameters were not correlated in OVX rats treated with fluoride. The heat-labile bone-specific alkaline phosphatase in plasma was decreased in OVX rats treated with fluoride compared to OVX rats, suggesting that both the number and the activity of osteoblasts were affected by NaF treatment. To examine the effect of fluoride on the osteocalcin production and the proliferative capacity of bone cells, osteoblastic cells were isolated by collagenase digestion from the bone surface of tibia in treated and untreated OVX rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of fluoride on bone and bone cells in ovariectomized rats. 144 10

Transamidases are a class of calcium-dependent mammalian enzymes which cross-link proteins by catalyzing the formation of (gamma-glutamyl)-epsilon-lysine bonds. It is possible that these enzymes play an important anabolic role in tissue healing. This study was to quantitate transamidase activity in human gingival tissue and examine the relation between transmidase activity and degree of inflammation. Forty-four out of a total 120 collected human gingival specimens from healthy and diseased patients were selected based on histometric and microbiologic criteria. Specimens were minced and homogenized in 10 mM CaCl2 and then extracted for 30 min, in 50 mM tris-HCl buffer (pH 7.5) containing 100 mM CaCl2. Following low speed centrifugation at 4 degrees C, the supernatant solution was assayed for both transamidase and collagenase activities by radioactive amine incorporation, and digestion of tritiated collagen, respectively. Appreciable levels of transamidase and collagenase activities in healthy gingivae were found. These enzyme activities were significantly elevated in the diseased and healing tissues. Unlike other transamidases, calcium was required in the enzyme extraction process.
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PMID:Transamidase and collagenase activity in healthy and diseased human gingival tissues. 146 May 85

The ability of low-dose tetracyclines to inhibit collagenase activity and inactivate osteoclasts suggests that these compounds have great potential as a prophylaxis for metabolic bone disease. However, the cellular mechanism by which tetracyclines interact with skeletal tissue is not yet clear. To better understand the effects of tetracyclines on bone metabolism, we examined their effect on osteoclast activity in vitro. Because tetracyclines can enter the cell and bind calcium and have been reported to directly interact with osteoclasts, we postulated that exposure to either of two tetracyclines, minocycline or doxycycline, would alter cytosolic Ca2+ regulation in rat osteoclasts. [Ca2+]i was measured in single rat osteoclasts utilizing fura-2. Addition of extracellular Ca2+ (5 mM CaCl2), a potent osteoclast inhibitor, increased [Ca2+]i in all osteoclasts, but 10(-6) M salmon calcitonin (sCT) did so only in a subpopulation of osteoclasts. Neither minocycline nor doxycycline (10 micrograms/ml) altered steady-state osteoclast [Ca2+]i. Further, neither minocycline nor doxycycline pretreatment affected the sCT-mediated increases in [Ca2+]i. However, tetracycline pretreatment significantly decreased the cytosolic Ca2+ response to extracellular CaCl2. Our results strongly suggest that tetracyclines have a specific effect on extracellular Ca(2+)-stimulated cytosolic Ca2+ mobilization in osteoclasts, which is not solely dependent on their ability to buffer Ca2+. Furthermore, these results point to the potential use of tetracyclines as probes to study cytosolic Ca2+ regulation. However, that tetracyclines attenuate a signal response associated with decreased osteoclastic resorption suggests that the reported antiresorptive attributes of tetracyclines must be achieved independently of an effect on osteoclastic cytosolic Ca2+.
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PMID:Regulation of cytoplasmic calcium concentration in tetracycline-treated osteoclasts. 146 56


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