Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The preparation of cell suspensions by treatment of chick embryo hearts with collagenase at various stages of development is described. 2. Measurements of oxygen consumption, incorporation of labelled leucine into protein and accumulation of labelled alpha-aminoisobutyric acid against a concentration gradient indicated a long-lasting viability of the isolated heart cells in vitro; a satisfactory preservation of subcellular structures, including plasma membrane, was assessed by electron-microscopic examination. 3. The rate of alpha-aminoisobutyric acid accumulation by cardiac cells isolated from hearts at different stages of embryological development decreased with aging; insulin stimulated the intracellular accumulation of this amino acid analogue. 4. Insulin increased the uptake by isolated heart cells of several (14)C-labelled naturally occurring amino acids; however, the fraction of amino acid taken up by the cells that was recovered free intracellularly, and therefore the concentration ratio (between intracellular water and medium), was enhanced by the hormone only with glycine, proline, serine, threonine, histidine and methionine. When isolated heart cells were incubated in the presence of a mixture of labelled amino acids, the addition of insulin increased the disappearance of radioactivity from the medium. 5. The general pattern of amino acid transport (in the absence and in the presence of insulin) in isolated cardiac cells was similar to that found in intact hearts, suggesting that the biological preparation described in this paper might be useful for studies of cell permeability and insulin action.
...
PMID:Amino acid uptake in isolated chick embryo heart cells. 430 8

1. A method to separate the epithelium from the underlying layers of the frog skin is described. The method is based on the combined use of collagenase and hydrostatic pressures.2. The potential difference and the short-circuit current values of isolated epithelia and whole skins are similar. Na net flux and short-circuit current are equivalent.3. The time course of changes in potential following rapid changes in composition of the bathing solutions shows that the barrier to K diffusion at the internal surface of the isolated epithelium is larger than the barrier to Na diffusion at the external surface.4. In the isolated epithelium there are 133 m-mole K(+) and 24.7 m-mole Na/l. cellular water. The amount of extracellular water was considered to be equal to the inulin space.5. Arginine vasopressin (0.1 u./ml.) markedly increased short-circuit current and potential difference in isolated epithelia. The amount of Na in the epithelium that equilibrated with Na in the external solution was not increased by the hormone.6. Ouabain (10(-4)M) reduced short circuit current and potential difference to values close to zero. The ouabain treated epithelia contained an increased amount of Na originating in the internal solution. On the other hand the amount of Na that originated from the external solution was not increased.7. The amount of epithelial Na that equilibrated with Na in the external solution was 0.009 mu-equiv/cm(2). This figure is about ten times smaller than the values found in whole skins.
...
PMID:Sodium transport across the isolated epithelium of the frog skin. 432 24

Insoluble bone gelatin with inclusions of insoluble noncollagenous protein produces new bone when implanted in muscle in allogeneic rats. The implanted residue provides the milieu for expression of bone morphogenetic potential of migratory mesenchymal cells. Neutral buffer solutions activate endogenous enzymes that degrade components essential for cell interactions and differentiation of bone. Chloroform-methanol either denatures or extracts constituents responsible for degradation. Insoluble bone gelatin produces new bone after extraction at 2 degrees with neutral salts, 0.5 M EDTA, 0.1 M Tris.HCl, 4 M urea, 0.5 M hydroxylamine, and 10 M KCNS, as well as after limited digestion with pepsin or collagenase, but not after extraction with 5 M guanidine, 7 M urea, water saturated with phenol, or after alkali hydrolysis with 0.1 N NaOH. The specific activity of cell populations interacting with insoluble bone gelatin suggests that a chemical bond between collagen and a noncollagenous protein or part of a protein, cleaved by a neutral proteinase, controls the bone morphogenetic reaction.
...
PMID:Bone morphogenesis in implants of insoluble bone gelatin. 435 76

The properties of collagen films crosslinked by physical and chemical techniques were compared to the properties of films crosslinked with glutaraldehyde (GTA). Physical techniques studied include exposure to short wave (254 nm) u.v. irradiation and severe dehydration. Chemical techniques studied include immersion of collagen films in aqueous solutions of cyanamide or GTA. Collagen films exposed to combinations of aqueous solutions of cyanamide and severe dehydration had moduli of elasticity, swelling ratios and resistance to bacterial collagenase similar to films crosslinked with GTA. Theoretical calculations based on amino acid composition indicate that approximately seven times as many amino acid residues are capable of forming crosslinks using cyanamide or severe dehydration procedures as compared to GTA crosslinking. In addition, using severe dehydration or cyanamide forms crosslinks involving both amino and carboxyl residues which may allow these procedures to act synergistically. Based on our studies this two-step procedure effectively crosslinks collagen-based biomaterials while the only by-product of this reaction is water-soluble urea. Preliminary biocompatibility studies suggest that this crosslinking procedure may allow for pronounced tissue ingrowth.
...
PMID:Evaluation of collagen crosslinking techniques. 609 1

Young adult male F344 rats were given 90 ppm diethylnitrosamine in drinking water for 5 weeks. Cells were obtained in suspension from the livers of these animals by in situ perfusion of collagenase. Cells were separated in a 2.7-16% (wt/wt) continuous gradient of Ficoll in tissue culture medium in the Sorvall TZ-28 reorienting zonal rotor for 10 minutes at 4 degrees C with a centrifugal force of 12 X g at the sample-gradient interface (26 X g at the gradient-cushion interface). Up to half a billion liver cells were separated without exceeding the band capacity. In all experiments the purest fractions contained more than 90% hepatocytes. After centrifugation, 72.4 +/- 6.6% of the purified hepatocytes had histochemically demonstrable gamma-glutamyl transpeptidase (GGT). When purified hepatocytes were injected into the mesenteric veins of rats given a diet containing 0.02% (wt/wt) N-2-fluorenylacetamide for 7 days and subjected to partial hepatectomy, all rats that received these cells developed foci that exhibited histochemically demonstrable GGT. Hepatocytes with histochemically demonstrable GGT make up all or part of what previously has been referred to as "liver colony-forming units." With the TZ-28 reorienting zonal rotor, these cells can be purified in biochemically preparative quantities.
...
PMID:Purification and transplantation of hepatocytes from livers of carcinogen-treated rats. 612 27

Two Fischer 344 rat hepatoma cell strains, JM1 and JM2, have been isolated from a primary hepatocellular carcinoma. Primary tumor formation was induced in a two-thirds partially hepatectomized rat by a single low dose (70 mg/kg of diethylnitrosamine followed by chronic phenobarbital administration (0.1 g/100 ml drinking water). The primary tumors were passed three times by subcutaneous implantation of tumor fragments into the inguinal region of syngeneic recipients. The fourth pass was by injection of tumor cells directly into the livers of recipient rats. Several weeks later, the tumor-containing rat livers were subjected to collagenase perfusion. Two cell lines emerged from tissue culture of the cells isolated by perfusion. Each cell line was cloned by serial dilution. Cells JM1 and JM2 were tumorigenic when injected into syngeneic rats. The tumors, which arose from injected cell strains, exhibited several characteristics of hepatocellular carcinoma. Morphology was examined by light and electron microscopy. Histochemical studies of JM1 and JM2 cells grown in vitro and in vivo were done. The levels of tyrosine aminotransferase and three microsomal enzymes of importance to drug and carcinogen metabolism were investigated. To our knowledge, this is the first report of cell strains derived from an initiation promotion protocol in rats.
...
PMID:Establishment of two rat hepatoma cell strains produced by a carcinogen initiation, phenobarbital promotion protocol. 613 63

The NaOH sonication digestion technique permits rapid isolation and exposure of intact networks of elastic fibers in vascular tissue for 3-dimensional observation with the SEM. The configuration of the network of elastic fibers within the vascular wall of large elastic arteries (aorta) is generally agreed to be a flexible framework through which smooth muscle cells and collagenous fibers are interwoven. However, the configuration of elastic fiber networks in muscular arteries, medium sized veins and smaller vessels remains unknown. When the lengthy standard biochemical elastin purification techniques were applied to vessels containing lesser amounts of elastic tissue and finer elastic fibers, the vessels were completely digested. In contrast, the digestion and sonication technique isolated and exposed intact networks of delicate elastic fibers in blood vessels which do not contain large amounts of elastic tissue. Unfixed vessels were cut into short segments, placed in 0.5 N NaOH and sonicated for 20-40 min. The specimens were rinsed in deionized distilled H2O, then autoclaved for 30 min. The tissue was rinsed a second time, fixed and processed routinely for SEM. Elastic stains and enzymatic digestion with chromatographically purified elastase and collagenase confirmed that the digestion and sonication technique produced clean, isolated networks of elastic fibers. Knowledge of the configuration of the networks of elastic fibers in different vessels enhances understanding of distensibility characteristics of individual vessels and serves as a baseline for studying alterations in the elastic framework which occur during aging and disease processes such as atherosclerosis, arterial hypertension and aneurysms.
...
PMID:A rapid digestive technique to expose networks of vascular elastic fibers for SEM observation. 620 43

Proximal straight tubules (S2 segments) swell rapidly in hypotonic media, but within a few minutes their volume returns toward control levels due to extrusion of K, Na, Cl, and water from the cytoplasm. In the present studies we determined the extent to which hydrostatic pressure (derived from the elastic tubule basement membrane (TBM) as the tubule enlarged in hypotonic medium) contributed to the regulation of cell volume. Removal of the TBM by collagenase had no effect on cell volume regulation in otherwise normal tubules. By contrast, tubules treated with ouabain, though they appeared to regulate their volumes in hypotonic media, were unable to do so in the presence of glycoside if the TBM had been removed with collagenase. This latter result is interpreted to show that hydrostatic pressure generated by extension of the TBM can cause "apparent" volume regulation when the sodium pump is blocked by ouabain. We conclude that normal proximal renal tubules regulate cell volume in hypotonic solutions by mechanisms that are dependent on the normal operation of the classical sodium pump.
...
PMID:Effect of collagenase and ouabain on renal cell volume in hypotonic media. 624 22

1. Individual cells were isolated from adult rats ventricular myocardium by a collagenase digestion procedure. 2. Steady membrane potentials recorded with conventional intracellular glass micro-electrodes from cells in a modified Krebs solution containing 3 . 8 mM-KCl and 0 . 5 mM-CaCl2 were less negative than -40 mV in most cells (-25 . 3 +/- 10 . 9 mV, mean +/- S.D., 211 cells). 3. After addition of the potassium selective ionophore valinomycin (60 nM) to the bathing solution all recorded membrane potentials were more negative than -60 mV (-74 . 8 +/- 7 . 0 mV, sixty-three cells). 4. The internal concentration of potassium in the cells was determined as 120 . 8 +/- 1 . 7 mM (+/- S.E., n = 24) by flame emission spectrometry after centrifugation through silicone oil, using tritiated water and D-[1-14C] mannitol to estimate total and extracellular water in the pellet. 5. In the majority of cells in the standard solution the membrane potential recorded within a few msec of penetration was more negative than -70 mV (-78 . 4 +/- 9 . 7 mV, seventy-three cells). In sixty-six cells penetration initiated an action potential which overshot zero by 31 . 3 +/- 7 . 1 mV. This overshoot was abolished by reducing the external sodium to 0 . 1 of the normal value, and reduced or abolished by addition of tetrodotoxin (30 microM). 6. Modifications of the standard bathing solution which increased the number of cells with steady recorded membrane potentials more negative than -60 mV were: isosmotic substitution of sucrose for NaCl; replacement of NaCl and KCl by sodium isethionate and potassium methyl sulphate; addition of 5 or 10 mM-CaCl2; addition of 10 mM-MnCl2. 7. For cells in solution containing 2 . 5 or 5 . 5 mM-CaCl2, input resistances estimated from the amplitude of hyperpolarizations evoked by 200 msec current pulses were approximately 40 M omega at a resting potential close to -80 mV and became much greater as cells were depolarized. Time constants measured at the resting potential were approximately 8 msec. 8. In certain conditions, repeated spontaneous action potentials were recorded from contracting cells, and in quiescent cells evoked action potentials could be initiated by applying brief depolarizing pulses through the micro-electrode. Action potentials were coincident with contractions. 9. It is concluded that the resting potential of these isolated cells is normally more negative than -70 mV, and that the cells retain the ionic mechanisms necessary for the generation of active currents.
...
PMID:Electrical properties of individual cells isolated from adult rat ventricular myocardium. 625 Dec 4

A method is described for accurate and reproducible determination of wet and dry weights of small articular cartilage samples. The water content of the articular cartilage samples before and after treatment with selective degradative enzymes and "artificial fibrillation" was determined. It was found that the water content of articular cartilage can be altered by changing the physical and chemical composition of articular cartilage. The combination of protein polysaccharide degradation and "fibrillation" causes an increase in articular cartilage water content, while collagenase and the combination of collagenase and "fibrillation" causes a decrease. The relationship between these findings and function of normal and osteoarthritic cartilage is discussed.
...
PMID:Water content of equine articular cartilage: effects of enzymatic degradation and "artificial fibrillation". 629 Jan 40


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

---