Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hydroxyapatite (HA) is a bioactive dental implant material which accelerates bone formation on its surface. The mechanism of this acceleration is not clear. The elucidation of the cell adhesion might be the key to the understanding of the bioactive mechanism of HA. In this study, we analyzed the adhesion of HOS human osteoblasts onto HA and titanium to find the particular adhesion to HA. In short-term cultures in fetal bovine serum-pre-coated materials, a significantly higher number of cells adhered to HA than to titanium. In addition, serum-free conditions with phosphate-buffered saline pre-coating or bovine serum albumin pre-coating materials were tested. The results were nearly the same among all pre-coating conditions, suggesting that the quantity of cell adhesion was not affected by serum components. However, in the morphological observations by SEM, the form of adhesion was found to differ among pre-coating conditions. The osteoblasts tightly adhered and spread onto both HA and titanium with serum pre-coating, whereas the cells loosely adhered and did not spread without serum. To evaluate the Arg-Gly-Asp (RGD) sequence-specific adhesion, we used synthetic RGD peptides for a competitive inhibition test. The results showed that RGD peptides remarkably inhibited the tight adhesion and spreading of osteoblasts onto HA, whereas they did not strongly inhibit adhesion and spreading onto titanium. These results demonstrate that the regulation of cell adhesion to HA is different from that to titanium. Our study suggests that the RGD-containing serum proteins might have a major role in regulating the specific adhesion of osteoblasts to HA, and in inducing enhanced cell growth and differentiation.
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PMID:RGD peptides regulate the specific adhesion scheme of osteoblasts to hydroxyapatite but not to titanium. 949 21

Semen cryopreservation processes generally decrease sperm quality and fertility rate, but this is highly dependent on the specific susceptibility of sperm cells to low temperatures. In order to study the effect of cooling, freezing, and thawing on ram spermatozoa, sperm viability (plasma membrane integrity), HOS test (hyposmotic swelling test), and individual motility were assessed in fresh, cooled, and frozen-thawed samples. The cryoprotective ability of four extenders [Triladyl-yolk (20% Triladyl, 20% egg yolk), Salamon (9.9% raffinose, 2% sodium citrate, 15% egg yolk, 5% glycerol), I.N. I.A. (6.31% Tes, 1.51% Tris, 6% egg yolk, 3% glycerol), and Fiser (F1: 3.25% Tris, 9.3% fructose, 1.7% citric acid, 25% egg yolk, 2% glycerol; F2: 0.68% sodium citrate, 0.15% TES, 0.36% glycine, 10.18% lactose, 1.18% raffinose, 0.5% fructose, 3.95% dextran (150,000-200, 000 MW); 12% of the obtained solution was replaced by the same volume of glycerol)] was tested, as well as the effect of adding various compounds (bovine lactalbumin and serum albumin, vitamin E, dithiothreitol, bull seminal plasma, glycine betaine, proline, phosphatidylcholine, and cholesterol) to Fiser's medium. Simultaneously, centrifugal counter-current distribution in an aqueous two-phase system was carried out to analyze the effect of the four extenders on sperm surface heterogeneity. The results showed that ram spermatozoa undergo a dramatic loss of heterogeneity, viability, motility, and positive response to the HOS test during freezing and thawing. These changes were partially prevented by diluting samples in Fiser's extender containing egg yolk and glycerol. A considerable increase in sperm quality with respect to that obtained in Fiser's control sample was achieved by the addition of bovine lactalbumin, vitamin E, bovine serum albumin, and bovine and ram seminal plasma.
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PMID:Improvement of ram sperm cryopreservation protocols assessed by sperm quality parameters and heterogeneity analysis. 969 24

In previous reports, it has been demonstrated that progesterone (P) stimulates capacitation, hyperactivation of human sperm motility and initiates the acrosome reaction (AR). This last effect has been related to the presence of non-genomic receptors for the steroid, localized on the sperm head plasma membrane. These receptors can be detected after treating spermatozoa with the non-permeable conjugate Progesterone - 3-(O-carboxymethyl) oxime: bovine serum albumin-fluorescein isothiocyanate (P-BSA-FITC). In the present study, the presence of progesterone receptors was determined in a selected sperm population with normal morphology and high progressive motility. In addition, other parameters such as the AR, hypo-osmotic swelling test, stability of chromatin and capacitating effect of P were evaluated. The percentage of P-BSA-FITC positive-spermatozoa present in the selected sperm population was higher than in total seminal spermatozoa. Furthermore, spermatozoa incubated with P showed a higher percentage motility and AR than did control spermatozoa. The HOS test indicated that membrane integrity of P-treated spermatozoa was not different to that found in the control sperm suspensions. Unexpectedly, the total sperm population treated with P showed a marked susceptibility to nuclear decondensation with reducing agents. According to these results, the selected sperm population of this study, able to respond to P, may be similar to that with good motility and normal morphology selected in the female reproductive tract, before fertilization.
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PMID:Detection of progesterone receptors in human spermatozoa and their correlation with morphological and functional properties. 1145 77

Myeloperoxidase, released by activated phagocytes, forms reactive oxidants by catalysing the reaction of halide and pseudo-halide ions with H(2)O(2). These oxidants have been linked to tissue damage in a range of inflammatory diseases. With physiological levels of halide and pseudo-halide ions, similar amounts of HOCl (hypochlorous acid) and HOSCN (hypothiocyanous acid) are produced by myeloperoxidase. Although the importance of HOSCN in initiating cellular damage via thiol oxidation is becoming increasingly recognized, there are limited data on the reactions of HOSCN with other targets. In the present study, the products of the reaction of HOSCN with proteins has been studied. With albumin, thiols are oxidized preferentially forming unstable sulfenyl thiocyanate derivatives, as evidenced by the reversible incorporation of (14)C from HOS(14)CN. On consumption of the HSA (human serum albumin) free thiol group, the formation of stable (14)C-containing products and oxidation of tryptophan residues are observed. Oxidation of tryptophan residues is observed on reaction of HOSCN with other proteins (including myoglobin, lysozyme and trypsin inhibitor), but not free tryptophan, or tryptophan-containing peptides. Peptide mass mapping studies with HOSCN-treated myoglobin, showed the addition of two oxygen atoms on either Trp(7) or Trp(14) with equimolar or less oxidant, and the addition of a further two oxygen atoms to the other tryptophan with higher oxidant concentrations (> or = 2-fold). Tryptophan oxidation was observed on treating myoglobin with HOSCN in the presence of glutathione and ascorbate. Thus tryptophan residues are likely to be favourable targets for the reaction in biological systems, and the oxidation products formed may be useful biomarkers of HOSCN-mediated protein oxidation.
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PMID:Tryptophan residues are targets in hypothiocyanous acid-mediated protein oxidation. 1865 72

GSK812397 is a potent entry inhibitor of X4-tropic strains of HIV-1, as demonstrated in multiple in vitro cellular assays (e.g., in peripheral blood mononuclear cells [PBMCs] and a viral human osteosarcoma [HOS] assay, mean 50% inhibitory concentrations [IC50s]+/-standard errors of the means were 4.60+/-1.23 nM and 1.50+/-0.21 nM, respectively). The primary in vitro potency of GSK812397 was not significantly altered by the addition of serum proteins (2.55 [+/-0.12]-fold shift in the presence of human serum albumin and alpha-acid glycoprotein in the PBMC assay). Pharmacological characterization of GSK812397 in cell-based functional assays revealed it to be a noncompetitive antagonist of the CXCR4 receptor, with GSK812397 producing a concentration-dependent decrease in both an SDF-1-mediated chemotaxis and intracellular calcium release (IC50s were 0.34+/-0.01 nM and 2.41+/-0.50 nM, respectively). With respect to the antiviral activity of GSK812397, it was effective against a broad range of X4- and X4R5-utilizing clinical isolates. The potency and efficacy of GSK812397 were dependent on the individual isolate, with complete inhibition of infection observed with 24 of 30 isolates. GSK812397 did not show any detectable in vitro cytotoxicity and was highly selective for CXCR4, as determined using a wide range of receptors, enzymes, and transporters. Moreover, GSK812397 demonstrated acceptable pharmacokinetic properties and bioavailability across species. The data demonstrate that GSK812397 has antiviral activity against a broad range of X4-utilizing strains of HIV-1 via a noncompetitive antagonism of the CXCR4 receptor.
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PMID:Blockade of X4-tropic HIV-1 cellular entry by GSK812397, a potent noncompetitive CXCR4 receptor antagonist. 1994 58