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S Bain

Publications and source records attributed to S Bain.

29 records · Page 2Linked to original sources
PubMed1996

Ketoconazole and phorbol myristate acetate regulate osteoclast precursor fusion in primary murine marrow culture.

Osteoclast formation requires both precursor proliferation and then fusion into a multinuclear cell. These processes can be separated in primary murine marrow culture where osteoclastogenesis is stimulated by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). Here we investigate the regulation of precursor fusion. Ketoconazole, an agent known to inhibit cell fusion, added during the fusion period (days 5-6), dose-dependently inhibited formation of tartrate-resistant acid phosphatase+ (TRAP+) multinucleated cells (TRAP+MNCs), maximally at 62 +/- 4% (n = 10). TRAP+MNCs in cultures exposed to 48 h of ketoconazole (1 microM) during fusion had fewer nuclei compared with control (11.7 +/- 0.6 vs. 15.1 +/- 0.9). This inhibitory effect was completely reversed 24 h after removal of ketoconazole from culture. Phorbol myristate acetate (PMA) stimulated TRAP+MNC formation when given during the last 12 h of culture (2.3 +/- 0.2 fold compared with control). This increased formation was unaffected by the addition of hydroxyurea and accompanied by an increase in nuclei per TRAP+MNC (15.5 +/- 0.9 vs. 13.1 +/- 0.6). Finally, staurosporine decreased TRAP+MNC formation in the presence or absence of PMA, implying that protein kinase C is involved in fusogenic processes. Regulation of fusion appears to be another mechanism by which bone remodeling can be modulated in vivo.

Acid Phosphatase↗
PubMed1992

Captopril inhibits the fluorescence development associated with glycation of proteins.

Albumin and immunoglobulin G (IgG) show increased visible fluorescence in diabetic patients, IgG fluorescence being correlated with the presence of diabetic retinopathy. Captopril, an angiotensin converting enzyme (ACE) inhibitor, has free radical scavenging ability, attributable to its thiol group. We compared the scavenging effect of captopril (at doses between 0.5 and 100 microM) with perindoprilat, enalapril and enalaprilat (ACE inhibitors without scavenging ability) and two thiol-containing compounds, mercaptopropionylglycine (MPG) and N-acetylcysteine (NAC) (scavengers with no effect on ACE). Three systems were used to generate visible fluorescence in albumin and IgG; glycation, exposure to copper/hydrogen peroxide and gamma radiation. All three thiol-containing compounds inhibited fluorescence development in IgG and albumin, when fluorescence was generated by glycation or gamma radiation. Other ACE inhibitors had no effect with IgG. Enalapril and perindoprilat showed less effect than captopril with albumin; enalaprilat had no effect. No compound had any effect on fluorescence generation by copper/hydrogen peroxide. Captopril may have an additional antioxidant effect compared to other ACE inhibitors.

Albumins↗
PubMed1991

High-resolution linkage mapping for susceptibility genes in human polygenic disease: insulin-dependent diabetes mellitus and chromosome 11q.

Insulin-dependent diabetes mellitus (IDDM) has a complex pattern of genetic inheritance. In addition to genes mapping to the major histocompatibility complex (MHC), several lines of evidence point to the existence of other genetic susceptibility factors. Recent studies of the nonobese diabetic mouse (NOD) model of IDDM have suggested the presence, on mouse chromosome 9, of a susceptibility gene linked to the locus encoding the T-cell antigen, Thy-1. A region on human chromosome 11q is syntenic to this region on mouse chromosome 9. We have used a set of polymorphic DNA markers from chromosome 11q to investigate this region for linkage to a susceptibility gene in 81 multiplex diabetic pedigrees. The data were investigated by maximization of lod scores over genetic models and by multiple-locus affected-sib-pair analysis. We were able to exclude the presence of a susceptibility gene (location scores less than -2) throughout greater than 90% of the chromosome 11q homology region, under the assumption that the susceptibility factor would cause greater than 50% of affected sib pairs to share two alleles identical by descent. Theoretical estimates of the power to map susceptibility genes with a high-resolution map of linked markers in a candidate region were made, using HLA as a model locus. This result illustrates the feasibility that IDDM linkage studies using mapped sets of polymorphic DNA markers have, both for other areas of the genome in IDDM and for other polygenic diseases. The analytic approaches introduced here will be useful for affected-sib-pair studies of other complex phenotypes.

Chromosome Mapping↗
PubMedDate not supplied

Linkage between the fragile X and F9, DXS52 (St14), DXS98 (4D-8) and DXS105 (cX55.7).

Linkage data using the markers F9, DXS105 (cX55.7), DXS98 (4D-8) and DXS52 (St14) are presented from 22 kindreds segregating with the fragile X. Two-point linkage analysis was carried out taking into account cytogenetic results and penetrance classes defined by mental impairment status of mothers. Recombination frequencies (theta) corresponding to the maximum z scores (z) were obtained between F9 (z = 3.48, theta = 0.18), DXS105 (z = 5.06, theta = 0.07), DXS98 (z = 4.79, theta = 0.01) and DXS52 (z = 6.44, theta = 0.09) and the fragile X. Recombination frequencies between marker loci in fragile X families are also presented. These recombination frequencies need to be combined with those from other studies in order to determine the best estimates of map distances for use in genetic counselling, until markers closer to the fragile X, or at the fragile X, can be used. Most potential fra(X) heterozygotes were informative for flanking markers using the above 4 probes. Carrier risks were determined by 3-point analysis using informative flanking markers, taking into account cytogenetic results. Low level fra(X) expression occurred in 2 probable non-carriers; emphasising the need for extreme caution in the interpretation of low rates of expression.

Factor IX↗