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Biomedical subjects

H Chiba

Publications and source records attributed to H Chiba.

At least 217 records · Page 12Linked to original sources
PubMed1989

[Comparison of thallium perfusion and electrocardiographic findings at exercise thallium-201 scintigraphy with coronary arteriographic findings].

Findings of thallium-201 perfusion (Tl) and exercise electrocardiography (ECG) at exercise thallium-201 scintigraphy was compared with coronary arteriographic findings (CAG) in 283 patients. We classified these cases into four groups by Tl and ECG; [A] Tl(+).ECG(+), [B] Tl(+).ECG(-), [C] Tl(-).ECG(+), [D] Tl(-).ECG(-). Redistribution of thallium-201 was evaluated by qualitative (visual) analysis. Three percent of group A consisted of the patients with normal coronary artery, and thirty-eight percent of group D consisted of the patients with coronary artery disease. On exercise thallium-201 scintigraphic imagings, most of patients with normal coronary artery showed redistribution of inferior (24%) and septum (45%). On exercise electrocardiographic findings, most of patients with normal coronary artery showed ST-segment depression in II, III, aVF, V5 and V6. In patients with coronary artery disease, single vessel disease in group B was larger than that in group C (62% vs. 33%, p less than 0.05), and triple vessel disease and left main truncus disease in group C was larger than that in group B (37% vs. 10%, p less than 0.05). On exercise thallium-201 scintigraphic imagings, most of false negative in patients with coronary artery disease changed to true positive by quantitative analysis. The patients with less than 90% coronary stenosis in group C was larger than that in group B (65% vs. 100%).

Aged↗
PubMed1989

[Usefulness of coronary angioplasty (PTCA) of the infarct-related artery in patients with prior myocardial infarction--follow up of infarct zone pre- and post-angioplasty by stress thallium scan].

We studied the efficacy of coronary angioplasty (PTCA) of the infarct-related artery in 29 patients with prior myocardial infarction by stress thallium scan. Twenty-seven patients had anterior myocardial infarction (single LAD disease), one had inferior (single RCA disease) and one had posterior (single LCX disease). According to the stress-redistribution thallium scintigraphic finding before PTCA, the patients were classified in 4 groups; (A): three patients with complete redistribution. (B): fourteen patients with incomplete redistribution. (C): seven patients with partial redistribution. (D): five patients with no redistribution. After PTCA, the parameters of residual ischemia in the infarct area (% RD and Thallium ischemic score = TIS) were improved significantly but those of infarct size (RD% uptake and Defect Score = DS) were improved slightly in group A. In group B and C, % RD, TIS, RD% uptake and DS were all improved significantly. In group D, TIS was improved slightly and DS was improved slowly 3 months after PTCA. Group A had high probability of viable muscle and group D had high probability of scar at the infarct zone. Group B and C showed intermediate type between group A and D. The change of infarct area after PTCA was variable in 4 groups but both residual ischemia and infarct size decreased in all groups. Thus, PTCA of infarct-related coronary artery is useful even in the patients with prior myocardial infarction.

Adult↗
PubMed1988

Erythropoietin receptor of a human leukemic cell line with erythroid characteristics.

A new cell line of human erythroleukemia cells differentiates spontaneously so that 30% of the cells are always hemoglobinized. Erythropoietin did not affect the percentage of such cells but stimulated the cell growth, indicating that the cells have functioning receptors. Binding of human recombinant radioiodinated erythropoietin to the receptors was specific. The bound ligand was internalized into cells at 37 degrees C but not at 15 degrees C. Scatchard analysis showed two classes of binding sites. Covalent binding of erythropoietin to its receptors yielded two products detected on sodium dodecyl sulfate-polyacrylamide gels electrophoresed under reducing conditions. Under non-reducing conditions, these species disappeared and larger products appeared.

Cell Differentiation↗
PubMed1988

Comparative structural study of N-linked oligosaccharides of urinary and recombinant erythropoietins.

The structures of the N-linked oligosaccharides of the urinary erythropoietin (u-EPO) purified from urine of aplastic anemic patients were analyzed and compared with those for recombinant erythropoietin (r-EPO) prepared with baby hamster kidney (BHK) cells. Asparagine-linked neutral oligosaccharides were released from each EPO protein by N-oligosaccharide glycopeptidase (almond) digestion. The reducing ends of the oligosaccharide chains thus obtained were aminated with a fluorescent reagent, 2-aminopyridine, and the mixture of pyridylamino derivatives of the oligosaccharides was separated by high-performance liquid chromatography (HPLC) on an ODS silica column. More than 8 and 13 kinds of oligosaccharide fractions for u-EPO and r-EPO (BHK), respectively, were completely separated by the one-step HPLC procedure. The structure of each oligosaccharide thus isolated was analyzed by a combination of sequential exoglycosidase digestion and another kind of HPLC with an amide-silica column. Furthermore, high-resolution proton nuclear magnetic resonance (1H NMR) spectroscopy and methylation analyses were carried out in the case of r-EPO (BHK).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Sequence↗
PubMed1988

Amino acid sequence of guinea pig liver transglutaminase from its cDNA sequence.

Transglutaminases (EC 2.3.2.13) catalyze the formation of epsilon-(gamma-glutamyl)lysine cross-links and the substitution of a variety of primary amines for the gamma-carboxamide groups of protein-bound glutaminyl residues. These enzymes are involved in many biological phenomena. In this paper, the complete amino acid sequence of guinea pig liver transglutaminase, a typical tissue-type nonzymogenic transglutaminase, was predicted by the cloning and sequence analysis of DNA complementary to its mRNA. The cDNA clones carrying the sequences for the 5'- and 3'-end regions of mRNA were obtained by use of the sequence of the partial-length cDNA of guinea pig liver transglutaminase [Ikura, K., Nasu, T., Yokota, H., Sasaki, R., & Chiba, H. (1987) Agric. Biol. Chem. 51, 957-961]. A total of 3695 bases were identified from sequence data of four overlapping cDNA clones. Northern blot analysis of guinea pig liver poly(A+) RNA showed a single species of mRNA with 3.7-3.8 kilobases, indicating that almost all of the mRNA sequence was analyzed. The composite cDNA sequence contained 68 bases of a 5'-untranslated region, 2073 bases of an open reading frame that encoded 691 amino acids, a stop codon (TAA), 1544 bases of a 3'-noncoding region, and a part of a poly(A) tail (7 bases). The molecular weight of guinea pig liver transglutaminase was calculated to be 76,620 from the amino acid sequence deduced, excluding the initiator Met. This enzyme contained no carbohydrate [Folk, J. E., & Chung, S. I. (1973) Adv. Enzymol. Relat. Areas Mol. Biol. 38, 109-191], but six potential Asn-linked glycosylation sites were found in the sequence deduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

[Ultrastructural observation of human papillomavirus particles in the uterine cervix intraepithelial neoplasia].

Using transmission electron microscopy (TEM), twenty two cases of an intraepithelial lesion in the uterine cervix have been examined for the presence of human papillomavirus (HPV) particles. In 21 of these cases (95%), HPV particles were detected in the nucleus, and in 5 cases, in the cytoplasm. The distribution of the intranuclear HPV particles was classified into 4 types. In only 2 cases did the exhibited particles show a geometrical crystalline array (type I). In most cases, the exhibited particles were either seen to show an aggregate non-crystalline array (type II) or were concentrated around the chromatin (type III). Some cases also were found to show particles that were scattered sporadically in the nucleoplasm (type IV).

Cytoplasm↗
PubMed1987

Characterization of erythropoietin receptor of murine erythroid cells.

Radioiodinated or biologically tritiated recombinant human erythropoietin was used to characterize receptors for this hormone on the surface of Friend erythroleukemic cells (745A and TSA8) and cells from mouse erythropoietic tissues (liver from fetus and spleen from animals made anemic by injection of Friend virus or phenylhydrazine). Specific binding of erythropoietin to these cells was time-dependent and dose-dependent. Binding studies at 37 degrees C showed that dissociation constants of erythropoietin-receptor complexes were in the range of 100-300 pM. The number of receptors on erythroleukemic cells increased after treatment with dimethylsulfoxide. Covalent binding of 125I-erythropoietin to its receptors with a cross-linking reagent, disuccinimidyl suberate or glutaraldehyde, resulted in the formation of two major radiolabeled products that migrated as 120-kDa and 140-kDa species on sodium dodecyl sulfate/polyacrylamide electrophoresis gels under reducing conditions. Under non-reducing conditions, both 120-kDa and 140-kDa species disappeared and two cross-linked products, a minor product with a molecular mass of 250 kDa and a major product of high molecular mass that kept it from migration into the separating gels, appeared. The relationship of the cross-linked products found under non-reducing conditions with those under reducing conditions remains to be clarified.

Animals↗
PubMed1987

Rhythmic slow wave observed on nocturnal sleep encephalogram in children with idiopathic nocturnal enuresis.

All-night sleep polygraphs, except the first night, were recorded for 15 patients with idiopathic nocturnal enuresis and 10 normal controls. Relations between sleep and the mechanism by which nocturnal enuresis is caused, with special emphasis on the occurrence of rhythmic slow waves (RSW), was studied. The following results were obtained. (a) There was no significant difference between the two groups in the proportions of the electroencephalographic (EEG) sleep stages, under the same conditions. (b) Nocturnal enuresis occurred with almost the same frequency in all sleep stages except stage 1 sleep and was higher in the second and third cycles. (c) Immediately before a nocturnal enuretic event, 6-7 Hz RSW continued for as long as 15-40 s in NREM sleep, or 3-5 Hz RSW was observed in REM sleep. (d) RSW was observed in enuretics and controls, and decreased with increase in age. However, RSW occurred more often, and age-related decrease was delayed in enuretic children. (e) RSW was induced by stimuli such as changes in sleep stages or body movement. During RSW, the variance of heart rate and respiration tended to be low. These results and the similarity between RSW and diffuse rhythmic theta suggest that RSW may be an expression of the process of maintaining a given sleep stage in children. These results may also be caused by the immaturity of the sleep mechanism in enuretic children. The long-lasting RSW on the sleep EEG was considered to be a sign of the onset of nocturnal enuresis.

Child↗