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Biomedical subjects

S Kanematsu

Publications and source records attributed to S Kanematsu.

At least 37 records · Page 2Linked to original sources
PubMed1991

Chloroplast and cytosol isozymes of CuZn-superoxide dismutase: their characteristic amino acid sequences.

Isozymes of CuZn-superoxide dismutase (SOD) were purified from angiosperms (spinach and rice), fern (horsetail) and green alga (Spirogyra). Occurrence of CuZn-SOD was confirmed by its purification in the group of green algae which shows the phragmoplast type of cell division. Purified CuZn-SODs are divided to chloroplast and cytosol types by their cellular localization and immunological properties. Their amino acid compositions, absorption spectra, CD spectra, and sensitivity to hydrogen peroxide also are distinguished from each other. All organisms including Spirogyra contain both types of isozyme. Thus, the divergence of the two types of CuZn-SOD isozyme occurred immediately after its acquisition by the most evolved green algae. Amino acid sequences of amino-terminal regions of CuZn-SOD isozymes from spinach, rice and horsetail were determined and compared with those of CuZn-SODs from other plants. The chloroplast and cytosol isozymes of CuZn-SOD show each characteristic sequences. Sequence differences among the cytosol CuZn-SODs are greater than those among the chloroplast CuZn-SODs. These observations indicate that each type of isozyme had independently evolved after the acquisition of CuZn-SOD.

Biological Evolution↗
PubMed1991

Chemically-synthesized gene encoding modified human superoxide dismutase: its construction, expression and properties of the product.

The gene encoding modified human superoxide dismutase (h-SOD) with 153 amino acid residues was constructed by chemical synthesis using the phosphoramidite method. The gene was designed so as to use bacterial codons for expression in prokaryotes and to introduce several unique restriction sites for further mutagenesis by the cassette exchange method. The distance between Shine-Dalgarno sequence and initiation codon was adjusted to maximum expression by using synthesized oligonucleotide. In addition, Cys 6 of h-SOD was changed to Ala to improve instability of native h-SOD. Synthesized structural gene of h-SOD was expressed in E. coli after induction of isopropyl beta-D-thiogalactoside by inserting the gene into the expression vector pKK223-3 having tac promoter. The gene that has 10 base pairs between Shine-Dalgarno sequence and initiation codon showed the most efficient expression. The gene produced three active SOD isomers as revealed by chromatofocusing. The main isomer was purified to homogeneity and characterized. The h-SOD-Ala6 showed similar properties to those of native h-SOD with respect to molecular weight, subunit structure, absorption spectrum, but the modified SOD was more resistant to heat denaturation than was native h-SOD; half-denaturing temperature was shifted by 10 degrees C. Thus, the exchange of Cys 6 to Ala of h-SOD increased a stability of the enzyme.

Amino Acid Sequence↗
PubMed1990

Effects of VIP and GRF on the release of growth hormone in perifused bovine adenohypophysis.

The effects of vasoactive intestinal polypeptide (VIP) and growth hormone releasing factor (GRF:hpGRF(1-29)-NH2) on the release of growth hormone (GH) from anterior pituitaries from cows were examined by using an in vitro superfusion system. The pituitaries were excised randomly from cycling cows, dissected to obtain medial portions, and minced to obtain cubes with approximate dimensions of 1.5mm on a side. For each perifusion setup, 5 pieces of pituitary tissues were chambered and flushed with modified KRB solution saturated with 95% O2-5% CO2 at 38C. Perifusion with media containing 10(-6) and 10(-7)M VIP for 30 min induced a significant release of GH during the treatments (P less than 0.05). VIP (10(-8)M) increased GH levels significantly (P less than 0.05), but to a minor degree. Perfusion with the media containing 10(-6), 10(-7) and 10(-8)M GRF for 30 min markedly increased the GH concentration and the effects continued up to 90 min after termination of the perifusion of the peptide (P less than 0.05, P less than 0.01). The GH releasing effects of GRF could be seen at doses as low as 10(-11)M GRF (P less than 0.05, P less than 0.01). These findings indicate that the GH releasing effect of VIP is less potent than that of GRF in cows.

Animals↗
PubMed1989

[Definitive diagnosis of early malignant melanoma lesions by the quantitative analysis of 5-S-cysteinyldopa in the tissue and touch fluorescence method].

Methods for making diagnoses of early lesions of malignant melanomas using a touch-fluorescence method from the cut surface of the lesions and quantitative analysis of 5-S-CD in the tissues were developed. 1) The touch-fluorescence method and analyses of 5-S-CD values in the tissues were extremely useful in making definitive diagnoses of early lesions of nodular melanoma (NM). 2) Only quantitative analyses of 5-S-CD values in the tissues were useful in making definitive diagnoses of early lesions of superficial spreading melanoma (SSM). 3) It is impossible to definitively diagnose lentigo maligna using either way mentioned above. From these results, it appears that quantitative analysis of 5-S-CD values in the tissue was the most useful method for making definitive diagnoses in case of early lesions of NM and SSM.

Adolescent↗
PubMed1986

Quick diagnosis of malignant melanoma with the touch-fluorescence method during operation.

Nine cases of primary melanotic melanoma, three cases of metastatic amelanotic melanoma, and 26 cases of pigmented and unpigmented tumors other than melanoma were examined with the touch-fluorescence method using preparations from the cut surface of the lesions. Fluorescent melanoma cells were easily detected with a fluorescence microscope in all the cases of malignant melanoma whether the melanoma was melanotic or amelanotic. The fluorescent melanoma cells could be divided into three types by configuration: round, spindle-shaped, and pleomorphic. The main cell type of superficial spreading melanoma was round and that of nodular melanoma and acral lentiginous melanoma was chiefly pleomorphic. Fluorescent tumor cells were not seen in pigmented and unpigmented tumors other than melanoma, except in pigmented basal cell epithelioma; this fact made it possible to apply this method routinely for quick diagnosis of malignant melanoma during operation.

Adult↗