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Biomedical subjects

N Utsumi

Publications and source records attributed to N Utsumi.

At least 55 records · Page 3Linked to original sources

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↗

Localization of hepatitis B surface antigen in the human parotid gland.

Localization of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) in the human parotid gland and liver was studied by an immunohistochemical method in four cases with seropositive HBsAg. Neither HBsAg nor HBcAg could be detected in the parenchymal cells of the parotid gland in any of the cases. However, one of four cases, which had the highest titer of serum HBsAg, showed HBsAg immunoreactivity in the vascular wall and luminal fluid of the parotid gland. In liver, HBsAg was detected in three and HBcAg in two of the four cases, respectively. HBsAg was localized in the cytoplasm of hepatocytes, while HBcAg was localized mainly in their nuclei. The detection of HBsAg in the parotid gland and liver was correlated with the serum titer of the antigen. The results indicate that the HB virus does not have an affinity for or a replicate in the parotid gland. Also, it is suggested that the HBsAg found in saliva is derived from HBsAg circulating through the oral mucosa by capillary leakage and not from secretion into the mouth by the salivary gland.

Adolescent↗

Immunohistochemical localization of nerve growth factor and epidermal growth factor in guinea pig prostate gland.

Prostate glands of adult guinea pigs were stained for nerve growth factor (NGF) and epidermal growth factor (EGF) by immunohistochemical methods. Both NGF and EGF were localized diffusely in the cytoplasm of the glandular epithelial cells, and also in their secretory products. These findings suggest that NGF and EGF are synthesized, stored, and secreted by the glandular epithelial cells of the prostate.

Animals↗

Effect of transferrin on alkaline phosphatase activity and collagen synthesis in osteoblastic cells derived from newborn mouse calvaria.

The effect of transferrin was tested on osteoblastic cells (clone MC3T3-E1) cultured in serum-free medium containing 1% bovine serum albumin (BSA). Transferrin (Tf) stimulated increases of protein content and protein synthesis, but not of DNA content and cell number, in the cells. This protein also increased alkaline phosphatase activity and collagen synthesis in combination with 1% BSA. Actinomycin D and cycloheximide inhibited alkaline phosphatase activity induced by Tf, suggesting that Tf may enhance de novo synthesis of the enzyme. These results indicate that Tf may be involved in differentiation of osteoblastic cells, but not in their proliferation, in vitro.

Alkaline Phosphatase↗

Selective inhibition of type I collagen synthesis in osteoblastic cells by epidermal growth factor.

We have investigated the effect of epidermal growth factor (EGF) on collagen metabolism in clonal MC3T3-E1 cells, an osteoblastic cell line derived from newborn mouse calvaria. EGF significantly increased DNA synthesis, but decreased collagen production. We analyzed the amount of total collagen synthesis and degradation products of collagen together with the level of the enzyme responsible for extracellular collagen degradation, to investigate whether the decreased collagen production was due to a decrease in total collagen synthesis or to an increase in collagen degradation. Total collagen synthesis, determined by total hydroxyproline synthesized, was significantly decreased in cells cultured in medium containing EGF, but the amount of collagen degradation products and the level of animal collagenase activity were not increased. Analysis of the collagen type produced by the cells in the absence of EGF showed that 95% of the collagen recovered was type I and 3% was type III. The decreased level of collagen accumulated by cells cultured in the presence of EGF was explained only by the decreased rate of type I collagen synthesis. These results indicate that EGF selectively inhibits type I collagen synthesis in the clonal osteoblastic cell line, MC3T3-E1.

Animals↗