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Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 379 records · Page 21Linked to original sources
PubMed1981

New anthracycline metabolites from mutant strains of Streptomyces galilaeus MA144-M1. II. Structure of 2-hydroxyaklavinone and new aklavinone glycosides.

Four blocked mutants of aclacinomycin-producing Streptomyces galilaeus MA144-M1 produced new anthracyclinones; 2-hydroxyaklavinone, its non-esterified analog and 2-hydroxy-7-deoxyaklavinone, several new anthracyclines; 2-deoxyfucosyl-2-deoxyfucosyl-rhodosaminylaklavinone (MA144 U1), 2-deoxyfucosyl-rhodosaminylaklavinone (MA144 U2) and five aklavinone glycosides devoid of amino sugar, designated as MA144 U5, U6, U7, U8 and U9.

Anthracyclines↗
PubMed1981

[Pituitary-adrenal cortical function in newborn infants--especially in the ratio of unbound unconjugated corticosteroids (author's transl)].

It has already generally been accepted that there are a variety of fetal adaptations to a stress during delivery and the fetal endocrinological functioning is being controlled mainly by the pituitary adrenal axis. An endocrinological difference between fetuses given a stress and the controls was observed in this study. The levels of ACTH and cds in the umbilical cord blood are supposed to be the indicators of stresses. The measurements of not only those levels but the percentile value of non-protein bound cds (NPC), known for an active form, were conducted under various conditions. Consequently, the three following results were obtained. 1. In the group of infants delivered by the vacuum extraction, the levels of ACTH and percent free cds tended to be more increased, and those of total cds and NPC were significantly higher than both groups of infants delivered spontaneously and by the oxytocin induction. 2. There were no significant differences in the levels of ACTH, total cds, percent free cds and NPC in plasma between the groups of mothers when delivered spontaneously and by the vacuum extraction. 3. The levels of ACTH, total cds, percent free cds and NPC in umbilical cord blood in infants with asphyxia were significantly higher than the normal.

Adrenal Cortex Hormones↗
PubMed1981

[Studies on the genesis of the aortic thudding sound in patients with aortic insufficiency, with special reference to the aortic flow pattern (author's transl)].

To clarify the genesis of the aortic thudding sound (AK), phono-, mechano- and pulsed Doppler echocardiography were performed in 16 patients with pure aortic insufficiency (AI), 3 with AI associated with mild aortic stenosis (AIs) and 5 with AI associated with mitral insufficiency (AI + MI). The results obtained were as follows: 1) AK was composed of two components, that is, one (AK1) occurred in early systole and the other (AK2) near the end point of an ejection systolic murmur. Patients studied were divided into 4 groups following the appearance of AK1 and/or AK2: group with only AK1 (4 cases), group with only AK2 (7 cases), group with both AK1 and AK2 (5 cases) and group without AK (8 cases). 2) AK1 was a low frequency sound and was well recorded from the cardiac base to the right supraclavicular region. AK1 was not observed in cases with mild to moderate AI and with AI associated with mild AS. In atrial fibrillation, when the preceding R-R intervals were long, AK1 was loud and appeared in early systole, and when short, small and in mid-systole. Marked augmentation of AK1 was observed in the first beat after premature ventricular contraction with a compensatory pause. 3) AK2 was also low in frequency and was most intensively recorded near the apex. Although the intensity of AK2 tended to increase in the severe cases of AI, AK2 could be observed in mild to moderate cases. Intensity of AK2 also showed the post-extrasystolic potentiation similar to that of AK1. 4) The carotid pulse showed pulsus bisferiens in all cases with AK2 (group with only AK2 and group with both AK1 and AK2). On the other hand, in cases without AK2 (group without AK and group with only AK1), carotid pulse showed a monophasic systolic wave except 3 cases. These results suggested that there was a close relationship between AK2 and pulsus bisferiens in the carotid pulse. (5) In the apex cardiogram (ACG), systolic notches coincident with AK1 and/or AK2 were observed in 10 of 12 cases with AK2 and in 4 of 9 cases with AK1. In cases without AK, however, no notch was seen in ACG. Therefore, these notches might be resulted from the shock of the anterior chest wall produced simultaneously with the occurrence of AK. 6) Flow patterns at the left ventricular outflow tract (aortic flow patterns) were recorded in 13 cases, including 3 with only AK1, 2 with only AK2, 3 with both AK1 and AK2 and 5 without AK. In 5 of 13 cases the flow patterns were recorded simultaneously with phonocardiograms. Systolic aortic flow showed biphasic patterns in all cases with AK2, and monophasic patterns in cases without AK2. AK1 occurred coincidentally with the first peak of the biphasic flow patterns, and AK2 with the second peak. These results suggested that AK1 might be produced by rapid ejection of massive amount of blood containing a regurgitant flow into the aorta with the ordinarily distensiblwe aortic wall, and AK2 by the clash between the second ejected flow and the reflected flow returning from the peripheral artery against the first ejected flow.

Adult↗
PubMed1980

Interaction between an organic hydroperoxide and an unsaturated phospholipid and alpha-tocopherol in model membranes.

The behavior of an organic hydroperoxide in the presence of lipid and/or alpha-tocopherol in model membranes has been studied using 14C-labeled cholesterol-5 alpha-hydroperoxide as the organic hydroperoxide. Cholesterol-F alpha-hydroperoxide in saturated phospholipid micelles is rapidly isomerized to cholesterol-7 alpha-hydroperoxide. Such an isomerization is inhibited by alpha-tocopherol, but not by an alpha-tocopheryl analogue with a substituted OH groups, present in the micelles, indicating the formation of hydrogen bonds between OH group in alpha-tocopherol and OOH group in the 5 alpha-hydroperoxide. The double bonds in unsaturated phospholipid can also serve to form a hydrogen bond with OOH in the 5 alpha-hydroperoxide moiety in the micelles. The resulting hydrogen-bonded complex could be decomposed by iron-induced lipid peroxidation, accompanied by isomerization of the 5 alpha-hydroperoxide and the further degradation to the 7-ketocholesterol and 7 alpha-hydroxycholesterol. When three components, such as unsaturated phospholipid, 5 alpha-hydroperoxide and alpha-tocopherol, are present in the same micelles, they form hydrogen bonded complexes. Such complexes could be decomposed by iron in the ferrous state, yielding mainly 5 alpha-hydroxycholesterol without significant change in the structure of alpha-tocopherol and peroxidative cleavage of unsaturated phospholipid.

Animals↗
PubMed1980

Current status of Japanese studies with the new anthracycline antibiotic aclacinomycin A.

Fundamental and clinical studies on a new yellow anthracycline antibiotic aclacinomycin A are reviewed. Favorable responses were seen in patients with acute leukemia refractory to daunomycin and adriamycin, malignant lymphoma, and breast, ovarian, lung, gastric, intestinal, and urinary bladder cancers by intravenous and intraperitoneal infusions or bladder instillation of aclacinomycin A alone in the phase II study.

Aclarubicin↗
PubMed1980

Effect of adenosine-5'-triphosphate-3'-diphosphate and related nucleoside polyphosphates on the spore germination of Streptomyces galilaeus.

Exogenous addition of adenosine- and guanosine 5'-(di- and tri) phosphate 3'-diphosphate (pppApp, ppApp, pppGpp and ppGpp) at the concentration of 0.5 mM inhibits spore germination of Streptomyces galilaeus ATCC 31133. This reversible inhibitory effect appeared to be at the transcriptional level, and also depends on the phase of spore germination; pppApp inhibited more strongly RNA synthesis in the period of the germ tube emergence than the early stage of germination. No inhibitory effect was observed with normal purine and pyrimidine nucleosides, nucleotides, pApp, pGpp, cyclic AMP and pyrophosphoric acid at the concentration of 0.1 - 1.0 mM.

Adenine Nucleotides↗
PubMed1980

A radioimmunoassay for guanosine-5'-diphosphate-3'-diphosphate and adenosine-5'-triphosphate-3'-diphosphate.

A radioimmunoassay for guanosine-5'-diphosphate-3'-diphosphate (ppGpp) and adenosine-5'-triphosphate-3'-diphosphate (pppApp) has been developed. The assay method is based on competition of an unlabeled highly phosphorylated nucleotide with 3H-labeled highly phosphorylated nucleotide for binding sites on a specific antibody. Antibodies to ppGpp and pppApp were obtained by immunizing rabbits with the antigen prepared by conjugating ppGpp with human serum albumin using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and with the antigen prepared by conjugating 8-(6-aminohexyl)amino-adenosine-5'-triphosphate-3'-diphosphate with human serum albumin using glutaraldehyde, respectively. Antibody-bound 3H-labeled highly phosphorylated nucleotides were separated from the free 3H-labeled highly phosphorylated nucleotides by selective adsorption on dextran-coated charcoal. Displacement plots were linear over a concentration range of 5-1,000 pmol/assay tube in a log-probit percentage plot. Application of this method to biological systems offers improved accuracy and convenience compared with the previous 32PO4-labeling technique.

Adenine Nucleotides↗
PubMed1980

Microbial conversion of anthracyclinones to daunomycin by blocked mutants of Streptomyces coeruleorubidus.

Baumycin-negative mutants of Streptomyces coeruleorubidus ME130-A4 do not convert daunomycinone to daunomycin and baumycins. They biosynthesize daunomycin from aklavinone and epsilon-rhodomycinone, indicating the glycosidation of the aglycone before the synthesis of daunomycinone. The biosynthetic pathway from epsilon-rhodomycinone to daunomycin was further confirmed by studying the bioconversion of anthracyclinones and anthracyclines, which are presumed to be intermediates.

Biotransformation↗
PubMed1980

Chemical modification of anthracycline antibiotics. I. Demethoxycarbonylation, 10-epimerization and 4-o-methylation of aclacinomycin A.

Demethoxycarbonyl derivatives of aclacinomycin A and of its 7-epimer, 10-epi-aclacinomycin A and 4-O-methylaclacinomycin A were chemically derived from aclacinomycin A. The cytotoxicity and inhibitory effects of RNA and DNA synthesis in cultured L1210 leukemia cells of the 4-O-methyl derivative approximated that of aclacinomycin A, while the demethoxycarbonyl derivatives and 10-epi-aclacinomycin A exhibited decreased activities in comparison with the parent compound.

Aclarubicin↗