Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of polymethylmethacrylate (PMMA) on DNA, protein, and sulfated-proteoglycan synthesis by rabbit articular chondrocytes were observed in monolayer cultures. PMMA pellets in ratios of 1:1 and 1:2 (liquid monomer:powder) significantly reduced [3H]thymidine incorporation into DNA during the first 24 h of culture and less so after 48 and 72 h. The reduction in [3H]thymidine incorporation was restricted to the cohort of chondrocytes nearest the PMMA. Consequently, cellular proliferation was unaltered by PMMA. By contrast, PMMA failed to inhibit [3H]leucine or [3H]serine/35SO4 incorporation. Both control and PMMA (1:1)-treated chondrocyte CsCl density gradient medium fraction dA1 eluted as a retarded peak on Sepharose CL-2B under associative conditions. The average partition coefficient (Kav) of PMMA-treated fraction dA1 was 0.41, as compared with 0.27 for control cultures. The Kav of medium fraction dD1 (proteoglycan monomer) was unaltered. Both control and PMMA-treated dA1 fraction elution profiles on Sepharose CL-2B were altered by incubation with Streptomyces hyaluronidase, indicating the presence of proteoglycan aggregate. The PMMA-treated cultures synthesized smaller proteoglycan aggregates. Since PMMA has been a critical factor in the success of total joint arthroplasty, defining interactions of differentiated cells with the cement is imperative for an understanding of the effects of PMMA on the biology of cartilage and bone.
 ...
PMID:Effects of polymethylmethacrylate on rabbit articular chondrocytes in monolayer culture. 638 80

The foregoing discussion indicates that hyaluronidases probably play an important part in the control of development. In morphogenesis, they may be involved in epithelial-mesenchymal inductive interactions, in non-malignant invasion when one tissue displaces another in normal development, in controlling cell movements, in modulating changes of shape of cells and sheets of cells, in controlling the permeability of tissues and regulating the ionic environment within the embryo. There is also evidence indicating that hyaluronidases are involved in the initiation of cytodifferentiation pathways, perhaps via direct or indirect effects upon the cell division cycle and histone-DNA interactions. The evidence presented indicates that hyaluronidases are important repeatedly at different stages of embryonic development and differentiation, where periods of high activity follow others of reduced activity in localized regions of the embryo. Some new results were also presented, showing the presence of different hyaluronidase activities at early stages of chick embryo development. The highest levels of hyaluronidase activity were found in the primitive streak and mesoderm.
 ...
PMID:Mini-review: hyaluronidases in early embryonic development. 638 51

Premolar and third molar dental pulps were studied. The amount of collagen in the dried pulps was 25.7 per cent in premolars and 31.9 per cent in third molars. These percentages are much higher than those reported for pulps in other species. Significant differences were further found in the collagen content and cell distribution (DNA) of the coronal, middle and apical parts of the pulp. Collagen content was the lowest in the coronal part, while the cell content was the lowest in the middle part. The extractability of collagen in a neutral salt solution or 0.5 M acetic acid was found to be extremely low (less than 1 per cent). Pretreatment of the pulp with hyaluronidase in order to remove proteoglycans had no effect on the solubility. It is concluded that human pulp collagen is highly cross-linked and cannot be considered as immature. Characterization of collagen was performed by methods in which limited pepsin digestion or CNBr cleavage was used. The digests were analysed by means of quantitative electrophoresis which revealed an amount of 42.6 per cent type III of the total collagen. Because of the large differences between dental pulps from man and experimental animals, extreme caution should be exercised in drawing conclusions from data of other species to explain phenomena observed in human teeth.
 ...
PMID:The concentration, extractability and characterization of collagen in human dental pulp. 641 Oct 48

The surface of rat arterial smooth muscle cells was characterized with respect to some of its chemical and functional properties. The effects of selective enzymic degradations (hyaluronidase, chondroitinases, heparitinase or neuraminidase) on [35S]sulphate-prelabelled cells and on binding sites for cationized ferritin (CF) were examined to assess the presence and relative importance of individual species of macromolecules on the cell surface. The results indicate that about half of the strongly anionic sites on the cell surface (binding CF at pH 2.0) could be ascribed to sulphate groups of glycosaminoglycans and about half to carboxyl groups of sialic acid residues in glycoproteins and/or glycolipids. Weaker anionic sites (binding CF at pH 7.0) largely originated from carboxyl groups of glycosaminoglycans. Chondroitin sulphate and heparan sulphate were the main glycosaminoglycans. The surface of cells from young animals showed a higher glycosaminoglycan and a lower sialic acid content than that of cells from adult animals. Continuous treatment of the cultures with neuraminidase stimulated serum-induced initiation of DNA synthesis, while treatment with hyaluronidase or heparitinase inhibited it. Addition of hyaluronic acid, heparin or heparan sulphate to the culture medium inhibited initiation of DNA synthesis as well as cell proliferation. The effect was more marked in cultures of cells from young animals than from adults, although the latter cells were found to grow at a higher rate and to higher densities. These results suggest a role for cell-surface and pericellular glycoconjugates in growth regulation. A possible mechanism of action is that these molecules, due to their anionic charge or by steric exclusion, interfere with the binding of platelet-derived growth factor, a highly cationic polypeptide, to its cell-surface receptor.
 ...
PMID:Cell surface components and growth regulation in cultivated arterial smooth muscle cells. 642 Apr 21

Hepatocytes were prepared from rainbow trout by perfusion in situ with collagenase and hyaluronidase. Preparations normally showed high initial viability (95 +/- 5% dye exclusion, 92 +/- 5% lactate dehydrogenase retention) and gradually decreased in viability and glutathione concentration over 5 hours. Cellular metabolism of aflatoxin B1 (AFB1), a potent hepatocarcinogen, was characterized by an investigation of the following parameters: kinetics of AFB1 metabolism and DNA adduct formation, dose response, viabilities of detoxication and activation pathways with time, influence of organic solvents, and effect of variation in cell concentration. The AFB1 metabolites and DNA adducts were resolved and quantitated by high-performance liquid chromatography. From these results a standardized assay procedure was derived which we used to examine AFB1 metabolism and DNA adduct formation in hepatocytes from fish fed dietary substances known to alter the carcinogenic response to this mycotoxin. Dietary beta-naphthoflavone, which strongly inhibits AFB1 carcinogenesis in rainbow trout, dramatically and reproducibly altered AFB1 binding and metabolism in isolated hepatocytes. Overall rate of AFB1 metabolism and rates of detoxication reactions increased, whereas DNA binding decreased. Dietary cyclopropenoid fatty acids, powerful synergists and promoters of AFB1 carcinogenesis in trout, also repressed AFB1-DNA binding. Both dietary factors appeared to depress initial DNA damage by AFB1 but operated through different metabolic pathways to do so.
 ...
PMID:Dietary modification of aflatoxin B1 carcinogenesis: mechanism studies with isolated hepatocytes from rainbow trout. 643 Dec 90

Our aim was to develop a fibroblast-free monolayer culture of human gastric mucosal cells, using the specimens obtained by routine endoscopic biopsy. Human gastric mucosa obtained from normal volunteers by endoscopic biopsy was dissociated from collagenase and hyaluronidase. Dissociated cells were cultured in supplemented Coon's modified Ham's F-12 medium. Within 24 hr of inoculation, the cells were attached to the culture dishes. This was followed by cellular outgrowth. On phase-contrast microscopy, all cells had epithelial characteristics and fibroblasts were not observed. Ninety percent of cells contained periodic acid Schiff reaction-positive mucous granules after diastase digestion consistent with mucous epithelial cells. Two percent of the cells gave a strong reaction for succinic dehydrogenase activity (parietal cells). Immunohistochemical staining for pepsinogen in cultured cells was negative. On EM, microvilli-like projections, junctional complexes, Golgi apparatus, and mucous granules were apparent in the majority of cells. Mitotic figures were observed by day 3 with Giemsa staining. Autoradiographically, these cells were able to incorporate [3H]TdR into the nuclei. Cells were capable of synthesizing DNA, and this function was inhibited by cycloheximide. Cells could be cultured for up to two weeks without fibroblast contamination. A method of primary monolayer culture of human gastric mucosa obtained by a routine endoscopic biopsy has been successfully developed.
 ...
PMID:A monolayer culture of human gastric epithelial cells. 686 89

Rat liver nuclear matrix and similar structures derived from isolated Chironomus polytene chromosomes, nuclear envelopes, and intranuclear bodies of frog late oocytes (the karyospheres) were studied by electron microscopy with platinum shadowing and negative staining. We have shown that the treatment of whole nuclei, nuclear envelopes, polytene chromosomes, or karyospheres with nonionic detergent, high salt, and RNase and DNase followed by dilute alkali or hyaluronidase digestion reveals numerous rather uniform granules 25-30 nm in diameter. With omission of the nucleases the granules appear to be associated with DNA strands mostly organized in loops. Many granules form clusters and are arranged in linear or arch-like aggregates or cycles resembling the pore complexes. We suppose that these spherical bodies constitute a basic component of the nuclear matrix, chromosome scaffold, and nuclear envelope and are bound together by hyaluronic acid or some similar glycosaminoglycan.
 ...
PMID:Granules 25-30 nm in diameter: basic constituent of the nuclear matrix, chromosome scaffold, and nuclear envelope. 696 Mar 56

Using 3H-labelled glucocorticoids, the receptor activity of heart and liver cytosol preparations from various animal classes and species, the distribution of receptors in the myocardium from different divisions of rat heart and the number of glucocorticoid receptors in the myocyte preparations isolated from adult rat hearts after treatment of cardiac tissue with hyaluronidase and collagenase have been studied. The specific binding of 3H-dexametasone to bovine fetal heart endothelial cells as well as to some other cell cultures was investigated. The data obtained suggest that the bulk of the total receptor activity of the heart is accounted for contractile cells of the myocardium. The number of specific sites of glucocorticoid binding by whole myocyte cells (per 1 mg of protein) or by "crude nuclear fraction" (per 1 mg of DNA) is comparable to that for some other cell types, which are believed to be hormone-sensitive. However, by the number of receptors per single cell myocytes surpass all the other cell types under study.
 ...
PMID:[Evidence for the presence of glucocorticoid receptors in heart contractile cells]. 731 26

Rats were treated with twice daily injections of 100 microgram PG/rat for 15 days. PGA-1 had no effect. PGE-2 caused a significant increase in testicular weight, RNA content, hyaluronidase activity and number of spermatids. PGF-2 alpha produced a significant decrease in sorbitol dehydrogenase activity and DNA content. It is suggested that PGE-2 may be involved in later stages of spermatogenesis, i.e. conversion of spermatocytes to spermatids.
 ...
PMID:Effect of prostaglandins A-1, E-2 and F-2 alpha on spermatogenesis in rats. 735 86

Myocardial cells were isolated after treatment with collagenase (0.05%) and hyaluronidase (0.1%) by discontinuous-gradient centrifugation on 3% Ficoll. Nuclei derived from these myocardial cells were then fractionated on a discontinuous sucrose density gradient with the following steps: (I) 2.0M/2.3M, (II) 2.3M/2.4M, (III) 2.4M/2.5M, (IV) 2.5M/2.6M, and (V) 2.6M/2.85M. The myocardial nuclei were sedimented in the interfaces of gradient fractions (II) and (III). Nuclei from whole ventricles that had been treated with the enzymes before isolation sedimented into five major subsets of nuclei. These findings suggest that nuclei sedimented in the isopycnic gradient at fractions (II) and (III) are most probably derived from myocardial cells. However, this procedure is laborious and lengthy, and the recovery of myocardial-cell nuclei is low. An alternative method was developed to isolate an enriched fraction of myocardial-cell nuclei from whole ventricular tissue without exposing the tissues to enzyme digestion. These ventricular nuclei could be fractionated into five nuclear subsets by using the same discontinuous sucrose density gradient as that described above. The content of DNA, RNA and protein per nucleus for each band was determined. Although the DNA content per nucleus was constant (10pg), that of RNA varied from 1.5 to 4.5pg and that of protein from 16 to 24pg. Nuclei from each band were examined by light-microscopy: large nuclei occurred in the ligher regions whereas smaller nuclei were found in the denser regions of the gradient. From the size distribution pattern of myocardial-cell nuclei compared with that of total ventricular nuclei, it was found that nuclear subsets (II), (III), and (IV) were similar to myocardial nuclei. Electrophoretic analyses of the proteins solubilized in sodium dodecyl sulphate/phenol or Tris/EDTA/2-mercaptoethanol/phenol obtained from each nuclear subset indicate that these fractions are similar, with limited qualitative differences. These findings indicate that isolation of an enriched fraction of myocardial-cell nuclei could be achieved by discontinuous-sucrose-density-gradient centrifugation.
 ...
PMID:Fractionation of rat ventricular nuclei. 739 68


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