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Biomedical subjects

M Sekine

Publications and source records attributed to M Sekine.

At least 163 records · Page 9Linked to original sources
PubMed1984

Chemical synthesis of the 5'-terminal part bearing cap structure of messenger RNA of cytoplasmic polyhedrosis virus (CPV): m7G5'pppAmpG and m7G5'pppAmpGpU.

The 5'-terminal structures of mRNA bearing the so-called 'cap' from cytoplasmic polyhedrosis virus (CPV), m7G5' pppAmpG and m7G5' pppAmpGpU, were first chemically synthesized. S,S-Di(4-methoxyphenyl) N6-benzoyl-2'-O-methyladenosine 5'-phosphorodithioate ((ArS) 2pAbmz) was prepared by phosphorylation of the 5'-hydroxyl group of N6-benzoyl-2'-O-methyladenosine with S,S-di(4-methoxyphenyl) phosphorodithioate by TPS. By the triester approach using (ArS) 2pAbmz as starting material, the protected dinucleotide and trinucleotide bearing 5'-phosphate group were synthesized. The protective groups of the dinucleotide and trinucleotide were removed to obtain pAmpG and pAmpGpU, respectively. By the reaction of a capping agent ((PhS) ppm7G) with pAmpG and pAmpGpU in the presence of silver nitrate or iodine. The 5'-terminal structure of the messenger RNA strand of CPV which was labelled isotopically, was confirmed completely as m7G5' pppAmGpU by cochromatography with the materials chemically synthesized here.

Chemical Phenomena↗
PubMed1984

Adrenal medulla gangliosides.

The gangliosides were examined in adrenal glands of mouse, rat, guinea pig, rabbit, monkey, pig, ox and chicken. GM3 ganglioside was predominant in all examined animals except pig. In pig GD3 ganglioside was the major one. GM4 ganglioside was found in guinea pig and chicken. The distribution of sialic acid varied in each species. NeuNGly containing gangliosides were not detected in rat, guinea pig, rabbit and chicken. The other animals have both NeuNAc and NeuNGly containing gangliosides. Chromaffin granules from bovine adrenal medulla contain gangliosides at concentrations 3 and 7 times as great as microsomal and mitochondrial fractions, respectively. These gangliosides were NeuNAc-containing GM3 and NeuNGly containing GM3 in the same amount.

Adrenal Medulla↗
PubMed1984

Isolation and characterization of a novel disialoganglioside from bovine adrenal medulla.

A novel GDlb ganglioside which contains only N-glycolylneuraminic acid was isolated from bovine adrenal medulla by DEAE-Sephadex A-25 and Iatrobeads column chromatography. The concentration of this ganglioside was 0.9 nmol lipid-bound sialic acid per gram fresh tissue, which accounted for 2.7% of the disialoganglioside fraction. The structure was elucidated by sugar analysis, neuraminidase digestion, and permethylation studies. The complete structure of this ganglioside was identified as GDlb (NeuGc)2 or II3 (NeuGc)2-GgOse4Cer.

Adrenal Medulla↗
PubMed1984

Ganglioside composition of chromaffin granule membrane in bovine adrenal medulla.

The ganglioside composition of chromaffin granule membranes of bovine adrenal medulla was investigated. Two major gangliosides, which accounted for over 95% of total gangliosides, were characterized as GM3 (NeuAc) and GM3 (NeuGc) by thin layer chromatography (TLC) and gas-liquid chromatography (GLC). Chromaffin granule membranes contained a relatively higher concentration of gangliosides than the membranes of other subcellular organelles; three times higher than microsomal membranes and seven times higher than mitochondrial membranes. This high concentration of ganglioside in chromaffin granule membranes could contribute to the high concentration of gangliosides in the adrenal medulla as compared to other extraneural tissues.

Adrenal Medulla↗
PubMed1984

Gangliosides and neutral glycolipids in guinea pig adrenal glands.

Glycolipids were isolated from the adrenal glands of seven strains of guinea pig by DEAE-Sephadex and Iatrobeads column chromatographies. The average lipid-bound sialic acid content of the adrenal glands was estimated to be 96.0 +/- 30.4 nmol/g fresh tissue. The ganglioside fraction contained two major gangliosides which accounted for 82% of the total lipid-bound sialic acid. They were identified as N-acetylneuraminylgalactosylceramide (GM4) and N-acetylneuraminyllactosylceramide (GM3). The neutral glycolipid fraction contained one major and three minor glycolipids. The major glycolipid was identified as galactosylceramide, which accounted for 81% of the total glycolipid. The other three glycolipids were identified as Forssman glycolipid (7%), lactosylceramide (5%), and gangliotriaosylceramide (7%). In all strains examined, the glycolipid patterns were similar.

Adrenal Glands↗
PubMed1984

Improvement of bioavailability of poorly absorbed drugs. I. Effect of medium chain glyceride base on the rectal absorption of cefmetazole sodium in rats.

The effect of medium chain glyceride on the rectal absorption of cefmetazole sodium is investigated using an in situ experiment in rats. Each glyceride component of medium chain glyceride was separated using a high-performance liquid chromatographic method. The promoting effect of medium chain glyceride was found to be mainly due to glycerylmonocaprylate and dependent on the concentration of glycerylmonocaprylate. When cefmetazole sodium in medium chain glyceride solution was administered into the rectal lumen of rats, rapid absorption of the drug was observed leading to a residual amount of about 45% at 15 min after administration. The promoting effect of medium chain glyceride was found to be more effective in the rectum than in the small intestine.

Animals↗
PubMed1983

Liposomal heme as oxygen carrier under semi-physiological conditions. Orientation study of heme embedded in a phospholipid bilayer by an electrooptical method.

The meso-tetra(alpha,alpha,alpha,alpha(o-pivalamidophenyl]porphinato iron-mono(1-lauryl-2-methylimidazole) complex embedded in the bilayer of dimyristoylphosphatidylcholine (liposomal heme) binds molecular oxygen reversibly at pH 7 and 37 degrees C. Orientation of the iron porphyrin complex in the phospholipid bilayer was studied by electric birefringence and dichroism. It was observed that both the phospholipid bibilayer of liposome and the porphyrin plane are oriented nearly in parallel to the electric field. Therefore the angle between the porphyrin plane and the bilayer is considered to be practically small.

Circular Dichroism↗
PubMed1983

Gangliosides of hog skeletal muscle.

The ganglioside content of hog skeletal muscle was 27 nmol/g wet weight when calculated as lipid-bound sialic acid. The elution profile on DEAE-Sephadex A-25 column chromatography showed that the monosialoganglioside fraction (61% of total lipid-bound sialic acid) contained at least seven major gangliosides and that the disialoganglioside fraction (25%) contained four major ones. These gangliosides were purified by latrobeads column chromatography, and from the results of sugar analysis, specific enzymatic hydrolysis, a permethylation study and CrO3 oxidation, the structures of these gangliosides were determined to be as follows: A, GM3(NeuAc); B, GM3(NeuGc); C, sialosylparagloboside(NeuAc); D sialosylparagloboside (NeuGc); E, GM1(NeuAc); F, GM1(NeuGc); G, sialosyllactosaminylparagloboside(NeuAc) (monosialogangliosides) and H, GD1a(NeuAc, NeuAc); I, GD1a(NeuAc, NeuGc); J, GD1a(NeuGc, NeuGc); K, GD1b(NeuAc, NeuAc) (disialogangliosides), where NeuAc is N-acetylneuraminic acid and NeuGc is N-glycolylneuraminic acid as sialyl groups. The major fatty acids of gangliosides A, D and G were mainly C16:0, but those of the others, E, F, H, J and K, were C16:0, C18:0, C22:0 and C24:0. The long-chain bases were predominantly C18:1 sphingosine in all gangliosides.

Animals↗
PubMed1983

Effects of alcohol diet from the fetal period on lipid metabolism in rats.

The effects of maternal alcohol consumption on lipid metabolism in the litter liver were examined in the rat. Rats reared from their fetal period to adulthood with liquid alcohol diet (fetal alcohol group) did not show any lipid accumulation in the livers. Liver perfusion experiments showed an increased oxygen consumption in the liver to a load of physiological concentration of palmitate. On the contrary, the response of oxygen consumption in fetal control rat livers (reared with non-alcohol liquid diet) to palmitate was found to be depressed. 14CO2 production rate from 14C-palmitate in perfused livers showed a significant increase in fetal alcohol group as compared with controls. No difference in 14C-palmitate incorporation into tissue lipid was found between fetal alcohol and fetal control groups. These data indicate that when rats are treated with alcohol from fetal period they acquire an ability to elevate FFA oxidation in the liver through metabolic adaptation.

Animals↗
PubMed1983

Isolation and characterization of the trisialogangliosides from bovine adrenal medulla.

Trisialogangliosides were isolated from bovine adrenal medulla by DEAE-Sephadex A-25 and Iatrobeads column chromatography. Their structures were elucidated by sugar analysis, neuraminidase digestion, and permethylation studies. The complete structures of trisialogangliosides, A to D, were identified as follows. A: GT1b, IV3NeuAc, II3 (NeuAc)2-GgOse4Cer. B: GT1b(NeuAc/NeuAc-NeuGc-); IV3NeuAc, II3 (NeuAc alpha 2-8 NeuGc-)GgOse4Cer. C: GT1b (NeuGc/NeuAc-NeuAc-); IV3NeuGc, II3 (NeuAc alpha 2-8 NeuAc-)GgOse4Cer. D: GT1b (NeuAc/NeuGc-NeuGc-); IV3NeuAc, II3 (NeuGc alpha 2-8 NeuGc-)GgOse4Cer. Gangliosides B, C, and D, which contain N-glycolylneuraminic acid, have not previously been reported in the literature.

Adrenal Medulla↗
PubMed1982

Disialogangliosides in bovine adrenal medulla.

Gangliosides were isolated from bovine adrenal medulla by DEAE-Sephadex A-25 and Iatrobeads column chromatography. The disialo fraction contained five major gangliosides, A to E; together they accounted for 4.6% of the total lipid-bound sialic acid. On the basis of sugar analysis, permethylation, mild acid hydrolysis and neuraminidase degradation studies, the structures of these five gangliosides are characterized as follows: (formula: see text). The major fatty acids of the disialogangliosides were C16:0, C18:0, C22:0, C23:0, C24:0, and C24:1, which were characteristic of extraneural gangliosides.

Adrenal Medulla↗
PubMed1982

High-performance liquid chromatographic method for determination of cefmetazole in human serum.

A fast, specific, sensitive high-performance liquid chromatographic method for the determination of cefmetazole in human serum was developed. The serum samples were deproteinized by adding 5% trichloroacetic acid in methanol containing barbital as an internal standard and were injected onto a reverse-phase column (mu-Bondapak C18) with a mobile phase of 10 to 15% acetonitrile in 0.005 M citrate buffer (pH 5.4). Eluted components were detected by UV absorption at 254 nm. Cefmetazole and the internal standard were separated from interfering serum components by this method. The peak height ratio of cefmetazole to the internal standard was proportional to the cefmetazole concentration in the range from 0.4 to 100 micrograms/ml. Serum samples obtained from three patients after a single intravenous injection of cefmetazole were assayed by this method and by a microbiological method. There was a good correlation between two assay methods (correlation, coefficient, 0.98). The stability of cefmetazole in human serum was (correlation coefficient, 0.98). The stability of cefmetazole in human serum was also determined by this method. Cefmetazole was stable in human serum for 2 weeks at 4 degrees C or for at least 8 weeks if it was kept frozen. As the high-performance liquid chromatography method is simple, specific, accurate, and reproducible, it appears to be more suitable for routine assay of cephalosporins than other assay methods.

Biological Assay↗