PubMed Health⌕ Search

Biomedical subjects

D Fujimoto

Publications and source records attributed to D Fujimoto.

At least 55 records · Page 3Linked to original sources
PubMed1985

Age-related changes in the content of non-reducible crosslinks in rat mandibular bone.

Age-related changes in the content of non-reducible crosslink amino acids, pyridinoline and histidinoalanine, in rat mandibular bone were studied. The pyridinoline content markedly increased up to 12 months of age and thereafter slightly increased. The histidinoalanine content was low until 3 months of age, but thereafter increased significantly up to 24 months. Total collagen content remained constant throughout the experiment. From these results, pyridinoline and histidinoalanine may serve as markers for the maturation and senescence, respectively, of mandibular bone.

Aging↗
PubMed1984

Histone acetylation and deacetylation of nuclei from sea urchin Hemicentrotus pulcherrimus embryos during early stages of development.

Nuclei were isolated from sea urchin (Hemicentrotus pulcherrimus) embryos during early stages of development, and the rates of histone acetylation and deacetylation were examined. Histone acetylation was measured in the presence of 6 mM sodium n-butyrate, a potent inhibitor of deacetylase, and in the absence of the inhibitor. The deacetylation activity was estimated from the difference between the rates with and without the inhibitor. The activities of the acetylation and the deacetylation, and the ratio of deacetylation to acetylation were unchanged during the stages between early blastula and gastrula. Autoradiographic analysis of acetylated histones showed that all of the internal histones of the nucleosomes were acetylated and that no apparent difference was found in the pattern of the acetylated fractions during the stages compared.

Acetylation↗
PubMed1984

Promotion of collagen production by human fibroblasts with gastric cancer cells in vitro.

To elucidate the histogenesis of gastric scirrhous cancer, the promotion of collagen production by normal human skin fibroblasts (HSF-1) with human gastric cancer cells (KATO-III, MKN-45 and MKN-28) was investigated by direct coculture and parabiotic culture. Argyrophilic collagenous fibers were demonstrated among fibroblasts on both direct cocultures and parabiotic cultures of the fibroblasts with gastric cancer cells. Microscopic examination showed that these fibers appeared earlier and were more abundant and thicker in direct cocultures and parabiotic cultures than in single cultures of fibroblasts. Gastric cancer cells in single or parabiotic culture did not form argyrophilic fibers. For quantitative proof of the promotion of collagen production by fibroblasts with gastric cancer cells, hydroxyproline produced by fibroblasts was measured. Much higher fibroblast hydroxyproline values were obtained in parabiotic cultures with gastric cancer cell lines than in single cultures of HSF-1. Moreover, the rate of collagen synthesis by HSF-1 was much higher than that of any gastric cancer cell line tested. These results demonstrate that gastric cancer cells enhance collagen production by fibroblasts in vitro. This finding suggests that they may produce a factor promoting fibroblast collagen synthesis and that this may contribute to the formation of stromal collagen in human gastric scirrhous cancer.

Adenocarcinoma, Scirrhous↗
PubMed1984

Age variation in histidinoalanine cross-links in proteoglycan subunits from human articular cartilage.

The proteoglycan subunits isolated from human articular cartilage of various ages (ranging from the newborn to the mature adult) were analyzed for their content of histidinoalanine. It was noted that while the young juveniles and adolescents contained about 1 nmole of histidinoalanine per mg protein, the skeletally mature adults contained about twice this amount. Unlike many age-related changes in proteoglycan structure that occur prior to the end of growth, this variation would appear to be more related to maturation of the adult.

Adolescent↗
PubMed1984

Biochemical studies on the collagen of the palmar aponeurosis affected with Dupuytren's disease.

The palmar aponeurosis of patients affected with Dupuytren's disease was examined for collagen characteristics with regard to extractability, polymorphism, and posttranslational modifications, and the results were compared with those from normal subjects. The increased proportion of type III collagen relative to type I collagen in the affected tissue confirmed the previous findings in this disease. A slight but significant increase in a ratio of glucosylgalactosylhydroxylysine to galactosylhydroxylysine in the Dupuytren's tissue may be interpreted by the increase in the content of type III collagen. The affected tissue contained increased amounts of dihydroxylysinonorleucine as the reducible cross-link of collagen. These data support the view that Dupuytren's tissue contains collagen resembling that in granulation and embryonic tissues. Pyridinoline was shown to occur in normal and affected aponeurosis. No change in its content suggests that this cross-link is not involved in the pathogenesis of contracture in this disease.

Amino Acids↗
PubMed1984

Elevation of histidinoalanine in calcified human aortas.

The cross-links histidinoalanine (HA); pyridinoline (Pyr); desmosine (Des); and isodesmosine (Ides) in human atherosclerotic aortas were studied. Only HA showed a significant increase in calcified aortas, with a high concentration in the insoluble "mineralized" fraction, which was separated out after treatment of tissues with pronase E. The cross-links composition was similar among "mineralized" fractions prepared from tissues of varying degrees of calcification: values were 2.40; 0.10; 0.17; and 0.16 moles per 1000 moles of amino acid residues for HA; Pyr; Des; and Ides, respectively. The findings suggest that the HA-containing peptide may play an important role in the calcification process of aortic tissues.

Amino Acids↗
PubMed1983

Analysis of pyridinoline, a cross-linking compound of collagen fibers, in human urine.

Pyridinoline, a cross-linking compound of collagen fibers, was found in human urine. A significant portion of urinary pyridinoline was in free form. The ratio of total pyridinoline to creatinine changed with age. It was high in children and decreased with growth. It was low and constant in adults, and increased slightly in old age. It was increased significantly in patients with certain bone and joint diseases. Urinary pyridinoline may serve as a useful marker for the breakdown of collagen fibers of skeletal tissues.

Adolescent↗
PubMed1982

Photolysis of pyridinoline, a cross-linking amino acid of collagen, by ultraviolet light.

Pyridinoline, a cross-linking amino acid of collagen, was degraded by irradiation of ultraviolet light. The decomposition rate varied with pH of the solution and wavelength of irradiation light. The maximum of the degradation rate at individual pH coincides with the ultraviolet absorption maximum. Namely, it was maximally degraded by irradiation at 295 nm in acidic solution and at 325 nm in neutral and alkaline solution. At the optimum wavelength, the photolysis occurred more rapidly in neutral and alkaline solution than in acidic solution. The quantum yield in neutral solution was approximately 0.11 and independent of wavelength. One of the photolysis products was identified as hydroxylysine on an amino acid analyser, indicating that the cleavage of the pyridinium ring occurred.

Amino Acids↗