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The findings indicate that GPIIIb is not the major, essential collagen receptor for type I and III collagens. This would explain why all individuals with GPIIIb-deficient platelets examined so far are healthy and, in particular, show no apparent evidence of hemostatic problems. However, in contrast to control platelets, no aggregation and impaired platelet factor 4, beta-thromboglobulin, and ATP secretion was observed in response to type V collagen. Therefore, it is postulated that for type V collagen-induced aggregation both GPIa/IIa and GPIIIb Collagen biosynthesis in human oral submucous fibrosis fibroblast cultures.To investigate the mechanism of collagen accumulation in oral submucous fibrosis (OSF) tissues, we examined the biosynthesis of collagen in fibroblast cultures established from OSF lesions. Fibroblasts obtained from four of ten OSF specimens showed more than a 1-fold increase in the production of collagens compared with fibroblasts from age-, sex-, and passage-matched normal controls (p < 05).

When the relative amounts of collagen synthesis were estimated by SDS polyacrylamide gel electrophoresis, it was found that both OSF and control cells produced about 85% type I collagen and 15% type III collagen. The ratio of alpha 1(I) to alpha 2(I) chains was about 3:1 in OSF cells instead of the 2:1 expected for type I collagen. The excess alpha 1(I) chains could mean that collagen type I trimer was synthesized by the fibroblasts. These findings suggest that collagen overproduction and a reduced degradation of the structure-stable collagen type I trimer synthesized by OSF fibroblasts might contribute to the accumulation of collagen in OSF lesions in vivo. The mechanism(s) of increased procollagen production were analyzed by Northern blot, slot blot, and Southern blot. The OSF fibroblast strains with elevated collagen production also contained higher-than-normal levels of procollagen mRNA, and the ratios of alpha 1(I), alpha 2(I), and alpha 1(III) procollagen mRNAs were compatible with the results of corresponding procollagen alpha chains. ordinary cleanser of pro alpha 2(I) collagen gene in OSF fibroblasts was about 15.

No gene amplification was found. These results indicate that expression of these procollagen genes in cultured fibroblasts is regulated at the transcriptional Presence of phosphate-mediated cross-linkages in hard tissue collagens.Lack of collagen type specificity for lysyl hydroxylase isoforms.Lysyl hydroxylase is the enzyme catalyzing the formation of hydroxylysyl residues in collagens. Large differences in the extent of hydroxylysyl residues are found among collagen types. Three lysyl hydroxylase isoenzymes (LH1, LH2, LH3) have recently been characterized from human and mouse tissues. Nothing is known about the distribution of these isoforms within cells or whether they exhibit collagen type specificity.

ordinary squalane cleanser measured mRNA levels of the three isoforms, as well as the mRNAs of the main collagen types I, III, IV, and V and the alpha subunit of prolyl 4-hydroxylase, another enzyme involved in collagen biosynthesis, in different human cell lines. Large variations were found in mRNA expression of LH1 and LH2 but not LH3. Immunoblotting was utilized to confirm the results of Northern hybridization. The levels of mRNA of LH1, LH2, and the alpha subunit of prolyl 4-hydroxylase showed significant correlations with each other. The LH3 mRNA levels did not correlate with those of LH1, LH2, or the alpa subunit of prolyl 4-hydroxylase, clearly indicating a difference in the regulation of LH3. No correlation was observed between LH isoforms and individual collagen types, indicating a lack of collagen type specificity for lysyl hydroxylase isoforms. Our observations suggest that LH1, LH2, and the alpha subunit of prolyl 4-hydroxylase are coregulated together with total collagen synthesis but not with the specific collagen types and indicate that LH3 behaves differently from LH1 and LH2, implying a difference in their substrates.

These observations set the basis for further studies to define the functions of lysyl hydroxylase isoforms.Immunodetection of collagen types I, II, III, and IV for differentiation of liver fibrosis stages in patients with chronic HCV.The current study is aimed at evaluating serum collagens and other serum biochemical markers as useful, non-invasive markers of hepatic fibrosis associated with chronic hepatitis C virus (HCV). Collagen types I, II, III, and IV were detected in serum using ELISA and Western blot techniques. The ELISA levels of collagen I, II, III, and IV increased significantly with the progression of fibrosis staging. Based on receiver-operating characteristic (ROC) curve analysis, the collagen type III (70 kDa) and type IV (200 kDa) were more useful than other serum bio-markers for differentiating severe fibrosis from mild fibrosis. Multivariate discriminant analysis (MDA) selected a fibrosis discriminant score (FDS) = [245 + Collagen III (microg/mL) x 123 + Collagen IV (microg/mL) x 144 + ALT (U/mL) x 005] - [albumin(g/L) x 046].

The FDS correctly classified 87% of the severe fibrosis patients at a cut-off score = 2 (i.e., more than 2 indicated severe fibrotic liver and less than 2 indicated mild fibrotic liver) with specificity of 97%.