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Biomedical subjects

H Kosaka

Publications and source records attributed to H Kosaka.

At least 199 records · Page 11Linked to original sources
PubMed1981

Comparative study of carbohydrate-protein complexes. III. Peptide structures of the linkage region in proteoglycans of human, porcine and shark cartilages.

Chondroitin sulfite peptidoglycans were prepared by the pronase digestion of cartilages from human knee joints, porcine tracheae, and shark crania. The beta-elimination and sulfite addition reaction of these peptidoglycans yielded cysteic acid-containing peptides, and the amino acid sequences of some of them were determined. The finding that human and porcine peptidoglycans have the same sequence in the linkage region as that of the bovine peptidoglycan reported previously suggested that there is a common structural feature in the core proteins of these mammalian cartilage proteoglycans. The results also support the view that -Ser-Gly- is the minimum requisite for the formation of the xylosylserine linkage of proteochondroitin sulfates.

Amino Acids↗
PubMed1981

[The ultrastructure of a gangliocytoma (author's transl)].

The tumor tissue removed surgically from the left parietal subcortical area of a 16-year-old boy was studied by light and electron microscopy. Our results were identical to cases reported previously. By light microscopy, the neoplasm was composed mostly of mature and immature ganglion cells and glial cells. Ganglion cells with large nuclei and prominent nucleoli had characteristic Nissl substance in various amounts and they were encompassed in a network of fibrous connective tissue. Glial cells were mainly oligodendrocytic. Astrocytes were small in number and did not show neoplastic growth. By electron microscopy, mature ganglion cells contained dense core vesicles in their cytoplasm and processes. The size of the vesicles ranged from 100 to 200 nm. Furthermore ganglion cells were surrounded by their own processes and also processes of glial cells. Ganglion cells were rarely found in synaptic contact with adjacent processes. Instead, oligodendrocytes were sometimes situated adjacent to these ganglion cells. These findings suggest that the tumor under study may be of hamartomatous origin. Aside from mature ganglion cells and glial cells, immature cells were present. From viewing the architecture of these immature cells, we concluded that they were also ganglion cells.

Adolescent↗
PubMed1980

Failure to detect papovavirus-associated T antigens in human brain tumor cells by anticomplement immunofluorescence.

To probe the possible presence of papovavirus-related T antigen(s) in human brain tumors, the imprinted or cultured cells at various passage levels were examined by anticomplement immunofluorescence using antisera to T antigen of each BK virus, JC virus, and simian virus 40. No T antigen was demonstrated in any tests with cells derived from 69 patients with various brain tumors. Twenty-two tumor cell strains cultured in the presence of a tumor promoter, phorbol ester, also failed to show the T antigen.

Animals↗
PubMed1980

Studies on the alpha-L-iduronidase activity of beta-glucuronidase preparations from bovine liver, rat liver, and rat preputial gland.

A commercial preparation of bovine liver beta-glucuronidase contained two distinct enzyme species, both of which catalyze the hydrolysis of 4-methylumbelliferyl alpha-L-iduronide. The species with a molecular weight of about 290,000 was devoid of phenyl alpha-L-iduronidase activity and exhibited 4-methylumbelliferyl beta-D-glucuronidase activity. The species with a molecular weight of about 78,000 was active towards phenyl alpha-L-iduronide but lacked the latter activity. Studies of the kinetics of inhibition and heat inactivation suggested that the hydrolysis of 4-methylumbelliferyl alpha-L-iduronide is due to the beta-glucuronidase in the case of the 290,000-dalton species. The highly purified beta-glucuronidase preparations derived from rat preputial gland and liver lysosomes also exhibited 4-methylumbelliferyl alpha-L-iduronidase activity. These findings support the view that beta-glucuronidase can hydrolyze certain alpha-L-iduronide bonds and raise the possibility that beta-glucuronidase may play a role in the catabolism of iduronic acid-containing glycosaminoglycans.

Animals↗
PubMed1979

Stoichiometry of the reaction of oxyhemoglobin with nitrite.

During the reaction of oxyhemoglobin (HbO2) with nitrite, the concentration of residual nitrite, nitrate, oxygen, and methemoglobin (Hb+) was determined successively. The results obtained at various pH values indicate the following stoichiometry for the overall reaction: 4HbO2 + 4NO2- 4H+ leads to 4Hb+ + 4NO3- + O2 + 2H2 O (Hb denotes hemoglobin monomer). NO2- binds with methemoglobin noncooperatively with a binding constant of 340 M-1 at pH 7.4 and 25 degrees C. Thus, the major part of Hb+ produced is aquomethemoglobin, not methemoglobin nitrite, when less than 2 equivalents of nitrite is used for the oxidation.

Hemoglobin A↗
PubMed1978

Fluorometric measurement of urinary alpha-L-iduronidase activity.

A fluorogenic substrate for alpha-L-iduronidase, 4-methylumbelliferyl alpha-L-iduronide, has been newly synthesized and the enzyme activity has been measured in urine samples obtained from normal persons and patients suffering from mucopolysaccharidosis. Urine samples derived from a patient with Scheie syndrome showed greatly reduced activity compared with a normal adult at a similar age. This patient exhibited a high level of urinary excretion of dermatan sulfate and heparan sulfate, which could be interpreted in terms of her low alpha-L-iduronidase activity. The use of the fluorogenic substrate has some advantages over existing methods because of the high sensitivity and the relative ease of handling, and it should be useful not only for diagnosis but also for following the purification process of the enzyme.

Adult↗