PubMed Health⌕ Search

Biomedical subjects

M Yano

Publications and source records attributed to M Yano.

At least 559 records · Page 31Linked to original sources
PubMed1992

[Hematological values in fetal blood by cordocentesis].

Reference ranges for four hematological parameters--hemoglobin, hematocrit, white blood cell and platelet count--in each gestation were established from values for fetal blood samples obtained by cordocentesis from 72 pregnancies at 16-39 weeks gestation. These 72 fetuses turned out as normal or single malformations which should not affect fetal hematological values. Significant correlations were observed between hemoglobin, hematocrit and platelet counts and the number of weeks of gestation. No correlation was found between the white blood cell count and gestational age. Fetal anemia (hematocrit was below the lower limit of the 95% confidence interval) was found in 18 (7%) of all the fetuses that underwent cordocentesis, including nonimmune hydrops fetalis (8 cases), Rh isoimmunization (4 cases), twin-to-twin transfusion syndrome (3 cases), trisomy 18 (2 cases) and autoimmune thrombocytopenia (1 case). Of 26 hydropic fetuses, 8 (31%) were anemic. The prognosis of those fetuses depended on either the gestational age or the severity of the fetal anemia. Our results are useful in diagnosing fetal hematological disorders and to make decisions for fetal therapy.

Anemia↗
PubMed1992

[Two cases of broncholithiasis removed by bronchofiberscopy].

Two cases of broncholithiasis, removed bronchoscopically, are reported. Case 1 was a 38-year-old female who was admitted with hemoptysis. The chest tomogram showed calcification near the right middle lobe bronchus. Bronchoscopy revealed a broncholith in B4. Component analysis showed that more than 98% of this stone consisted of calcium carbonate. Case 2 was a 75-year-old male who was hospitalized because of continuous cough. The chest radiograph showed calcification and atelectasis in the right upper lobe. Bronchoscopically, right B3 was obstructed by a broncholith. After removal of the stone, the distal part of B3 was noted to be filled with pus. Analysis of the stone's composition revealed calcium phosphate (77%) and calcium carbonate (23%).

Adult↗
PubMed1991

Importance of the C-terminal region of big endothelin-1 for specific conversion by phosphoramidon-sensitive endothelin converting enzyme.

Based on our previous findings that phosphoramidon-sensitive endothelin (ET) converting enzyme (ECE) converts human big ET-1 but does not big ET-3, we investigated structural requirement for substrate peptide. We prepared shorter peptides of big ET-1 and measured hydrolysis of the Trp-Val bond of these peptides. Relative hydrolysis ratios of big ET-1(1-38), (1-37), (16-37), (1-31) and (17-26) were 1, 1.15, 3.71, 0.01 and 0, respectively. In addition, big ET-2 and big ET-3 were not significantly converted by ECE. These results suggest that the carboxyl-terminal sequence at residues 32-37 of big ET-1 is important for conversion, whereas the amino-terminal disulfide loop structure appears to interfere with access of ECE to big ET-1.

Amino Acid Sequence↗
PubMed1991

Local formation and degradation of endothelin-1 in guinea pig airway tissues.

Endothelin(ET)-1 and big ET-1 caused potent and sustained constriction of isolated guinea pig bronchus. The response to ET-1 was enhanced by phosphoramidon in a simple dose-related manner (0.01-1000 microM), while the response to big ET-1 was enhanced at lower doses (0.01-0.1 microM) but was suppressed at higher doses (100-1000 microM) of phosphoramidon. Big ET-1, when given intravenously (i.v.) to anesthetized guinea pigs, increased both bronchopulmonary inflation pressure and mean arterial blood pressure (2.5, 5, 10 nmol/kg i.v.). The pressor response to big ET-1 was attenuated by phosphoramidon dose-relatedly, while the pulmonary response was modified in a complex fashion composed of delayed onset and prolonged duration of action. These results suggest that ET converting as well as degrading enzymes coexist in the airway tissue and both enzymes are sensitive to phosphoramidon, so that phosphoramidon acts bifunctionally to reduce and stimulate the airway responses to big ET-1.

Animals↗
PubMed1991

[Ala1,3,11,15]endothelin-1 analogs with ETB agonistic activity.

A linear peptide analog of endothelin (ET)-1, [Ala1,3,11,15]ET-1 (4AlaET-1), and its truncated peptide analogs were synthesized to study the structural requirements of ET-1 for the recognition of ETs-nonselective ETB receptors. ET-1 exhibited sub-nanomolar binding to two distinct ET receptor subtypes (ETA and ETB), but 4AlaET-1 bound to ETB with an affinity 1,700 times higher than that seen during binding to ETA. The truncated linear peptides 4AlaET-1(6-21), 4AlaET-1(8-21) and N-acetyl-4AlaET-1(10-21) still had high affinity for ETB, whereas 4AlaET-1(6-20) and 4AlaET-1(11-21) displayed remarkably reduced affinity for ETB. Therefore, ET-1 requires the Glu10-Trp21 sequence for ETB binding, but not the disulfide bridges. These ETB-binding peptides elicit endothelium-dependent vasorelaxation of porcine pulmonary arteries in parallel with the binding affinity for ETB, suggesting that they are ETB agonists.

Amino Acid Sequence↗
PubMed1991

An endothelin receptor (ETA) antagonist isolated from Streptomyces misakiensis.

A competitive endothelin (ET) antagonist, BE-18257B, was isolated from the fermentation products of Streptomyces misakiensis. It is a novel cyclic pentapeptide, cyclo(-D-Glu-L-Ala-allo-D-Ile-L-Leu-D-Trp-), and binds to ETA receptors (ET-1 selective) in cardiovascular tissues, but not to ETB receptors (equally sensitive to isopeptides of ET family) in kidney, adrenal gland and cerebellum tissues. BE-18257B also antagonizes ET-1-induced vasoconstriction in rabbit iliac artery and pressor action in rats. Thus it is a selective ETA antagonist and should provide a valuable tool for elucidation of the pharmacological and pathophysiological roles of ET-1.

Animals↗
PubMed1991

Three-dimensional readout of flash x-ray images of living sperm in water by atomic-force microscopy.

The imaging of living specimens in water by x-ray microscopy can be greatly enhanced with the use of an intense flash x-ray source and sophisticated technologies for reading x-ray images. A subnanosecond [corrected] x-ray pulse from a laser-produced plasma was used to record the x-ray image of living sea urchin sperm in an x-ray resist. The resist relief was visualized at high resolution by atomic-force microscopy. Internal structure of the sperm head was evident, and the carbon density in a flagellum was estimated from the relief height.

Animals↗
PubMed1991

Phosphoramidon-sensitive endothelin-converting enzyme in the cytosol of cultured bovine endothelial cells.

Neutral metalloproteases with endothelin-1 (ET-1) converting activity were detected in membranous and cytosolic fractions of cultured endothelial cells (EC) from bovine carotid artery in a ratio of 5:1, respectively. The cytosolic enzyme specifically and quantitatively converts big ET-1 to ET-1 (Km = 10.7 microM), but does not convert big ET-3. Like the membranous enzyme, the cytosolic enzyme is only active at pH 6.5-7.5, and is competitively inhibited by phosphoramidon (Ki = 0.79 microM). The apparent molecular weight of the cytosolic enzyme is about 540 kD, which is 5-6 times greater than that of the membranous enzyme. These results indicate the presence of two types of phosphoramidon-sensitive neutral ET-converting enzyme in vascular EC.

Animals↗
PubMed1991

Endothelin converting enzyme of bovine carotid artery smooth muscles.

This is the first report clearly demonstrating the presence of endothelin (ET) converting enzyme in vascular smooth muscle. Like cultured endothelial cells, noncultured vascular smooth muscle homogenate of bovine carotid arteries, converts human big ET- 1 to ET-1 at pH 3.0, pH 5.0 and pH 7.0, and the apparent ratio of these three activities is about 6:5:1, respectively. Peptides generated during incubation of the homogenate and big ET- 1 at the three pHs were identified as ET- 1 by radioimmunoassay and high performance liquid chromatography. The two acid enzymes are in the cytosol (103,000xg sup) and are inhibited by pepstatin A, while the neutral enzyme is sensitive to EDTA or phosphoramidon; 73% of the neutral enzyme activity was membrane-bound and the remainder (27%) cytosolic.

Animals↗
PubMed1991

A high prevalence of antibody to the hepatitis C virus in patients with hepatocellular carcinoma in Japan.

In Japan, hepatocellular carcinoma (HCC) is one of the most prevalent cancers, with a reported fatality rate showing a consistent and significant increase in the last decade. At most, only 25% of HCC cases are positive for the hepatitis B surface antigen (HBsAg). To investigate a potential role for hepatitis C virus (HCV) in the development of HCC, sera from 105 HBsAg-negative HCC patients were collected from five districts of Japan and assayed for antibody to HCV antigen (HCVAb). A large number of these patients (76.2%) were found to be positive for the HCVAb in comparison with the reported prevalence in sera from blood donors (1.1%). A history of blood transfusion was found in 39.6% of the cases positive for HCVAb, which was significantly different to the lower rate (4.7%) observed in HCC patients who were both positive for HBsAg and negative for HCVAb (P less than 0.001).

Blood Transfusion↗
PubMed1991

Synthesis of human big endothelin-1 by sequence-specific proteolysis of a fusion protein in Escherichia coli.

Three DNA constructs, pETB-40, 41, and 42, encoding human big endothelin-1 (ET-1) preceded by the specific recognition sequence (Ile-Glu-Gly-Arg) for the activated blood coagulation factor Xa (FXa), fused in frame to the N-terminal portion of beta Gal, were expressed in Escherichia coli. The fusion proteins, pETB-40P, 41P, or 42P, consisted of the 55-, 51-, or 42-aa N-terminal peptide of beta Gal and the 38-aa of big ET-1, and had 1, 0, or 0 Cys residues and 5, 5, or 1 Arg residues in the N-terminal peptide of beta Gal, respectively. Enzymatic cleavage of the purified fusion proteins by FXa or trypsin allowed the recovery of authentic human big ET-1. The rates of conversion of pETB-40P, 41P, and 42P to big ET-1 by FXa digestion were 5.6, 11.2, and 30.0%, respectively. pETB-40P with a deletion of one Cys residue and four Arg residues in the N-terminal part was a better substrate than the other two for FXa or trypsin in the production of big ET-1.

Amino Acid Sequence↗
PubMed1991

Endothelin-converting enzyme and its in vitro and in vivo inhibition.

We investigated endothelin (ET)-converting enzyme and its localization in the vasculature. The membrane and cytosol fractions of cultured endothelial cells of bovine carotid artery contain phosphoramidon-sensitive ET-converting enzymes, and their molecular weights are about 100 and 540 kDa, respectively. The specific conversion of big ET-1 by these enzymes proceeds at pH 7.0 +/- 0.5, and it is inhibited by EDTA, o-phenanthroline, and phosphoramidon. Big ET-3 is converted by the membrane enzyme at a rate about one-tenth that of big ET-1, but it is not converted by the cytosol enzyme. Big ET-1 (but not ET-1)-induced hypertension in rats was remarkably suppressed by pretreatment with phosphoramidon, and big ET-1 (but not ET-1)-induced contraction of isolated coronary arteries, either with or without the endothelium, was substantially suppressed by phosphoramidon. These results suggest an essential role of phosphoramidon-sensitive enzyme(s) in the vascular conversion of big ET-1, and the existence of such enzymes also in nonendothelial cells. We found three converting enzymes operating at different optimal pH values in noncultured vascular smooth muscle cells; two pepstatin-sensitive, cytosolic acid proteinases and a phosphoramidon-sensitive neutral enzyme(s) in the membrane and cytosol. All of these findings strongly suggest the importance of phosphoramidon-sensitive neutral enzymes in the vascular conversion of big ET-1.

Animals↗
PubMed1991

Two endothelin receptor subtypes in porcine arteries.

Endothelin-1 (ET-1) and ET-3 caused constrictions of endothelium-denuded porcine coronary artery strips with different concentration-response curves: a typical sigmoidal curve to ET-1 and a two-phase sigmoidal curve to ET-3. Binding assays using a membrane preparation demonstrated different Bmax values for [125I]ET-1 and [125I]ET-3 binding. In addition, [125I]ET-1 binding was inhibited by ET-1 and ET-3 with different potencies (ET-1 greater than ET-3), while [125I]ET-3 binding was inhibited by both ETs equally. From these results, two distinct ET receptor subtypes were proposed in the artery; site 1 (selective to ET-1) and site 2 (equally sensitive to both ETs). However, only site 1 was identified on cultured arterial smooth muscle cells (VSMCs) by the binding assay, and this was confirmed since only ET-1 (not ET-3) caused a significant increase in the intracellular free Ca2+ concentration. Therefore, it seems likely that vasoconstriction is mediated via the binding of ET-1 to site 1 (VSMCs) and site 2 (non-VSMCs), or the binding of ET-3 to site 2 (non-VSMCs). Furthermore, site 2 was predominant in nonvascular tissues such as lung, kidney, and cerebellum, thereby suggesting that site 1 may exist in limited tissues such as VSMCs.

Animals↗
PubMed1991

Coronary vascular response to endothelin in isolated perfused hearts of spontaneously hypertensive rats.

1. The coronary vasoconstrictive response to endothelin (ET-1) was evaluated using the isolated perfused hearts of 15 week old spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). Endothelin produced marked increases in perfusion pressure (PP) in both SHR and WKY. The effects of ET-1 were more potent than those of acetylcholine, vasopressin and angiotensin II. The vascular response to ET-1, expressed as the increase in PP, was greater in SHR than in WKY. 2. Nicardipine (10(-8) mol/L) shifted the concentration-PP response curve for ET-1 to the right. The extent of the rightward shift was greater in SHR than in WKY. Additionally in SHR, Bay K-8644 elicited a dose-dependent increase in PP, the effect being more potent than that in WKY. 3. The increased response of the coronary vasculature to ET-1 was observed after 15 weeks of age but not at 6 weeks, indicating that enhancement of the response develops with ageing in SHR. 4. Enhancement of the vascular response to ET-1 in SHR was prevented by chronic (10 weeks) treatment with enalapril (10 mg/kg per day), but not by hydralazine (30 mg/kg per day). 5. These results indicate that the coronary vascular response to ET-1 increases with age in SHR. The mechanism of the enhanced response may involve the activation of dihydropyridine-sensitive Ca2+ channels, however, this type of mechanism may also be modulated at least in part by the renin-angiotensin system.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Antibody to the hepatitis C virus in acute hepatitis and chronic liver diseases in Japan.

In a 6-month follow-up study of acute hepatitis in Japan, 31 out of 41 (75.6%) cases of post-transfusion non-A and non-B hepatitis (NANB-PTH) and 14 out of 40 (35.0%) cases of sporadic non-A non-B hepatitis (NANB-SPO) were found to be positive for antibody to the hepatitis C virus (HCVAb). After 12 months of follow-up, 30 cases (81.1%) became chronic among 37 HCVAb positive acute NANB hepatitis cases. This figure shows a significantly higher rate of chronicity as compared with HCVAb negative acute NANB hepatitis. The prevalences of HCVAb in hepatitis B surface antigen (HBsAg) negative cases of chronic hepatitis and liver cirrhosis were 76.3% (200/262) and 66.7% (106/159), respectively, which were significantly different from the values of 5.1% (13/255) and 10.6% (13/123) observed in HBsAg positive cases. Of chronic liver disease cases positive for HCVAb, 45.8% (152/332) had a history of blood transfusion, in contrast to the value of 3.7% (13/352) observed in HBsAg positive cases of chronic liver disease that were negative for HCVAb.

Enzyme-Linked Immunosorbent Assay↗
PubMed1991

Use of a signature nucleotide sequence of hepatitis C virus for detection of viral RNA in human serum and plasma.

The nucleic acid sequence of the putative 5'-untranslated (5PUT) region of hepatitis C virus (HCV), determined for samples obtained from a variety of geographic origins, was found to be over 98% conserved among all isolates. On the basis of this signature sequence for HCV, a viral RNA assay was developed by using cDNA synthesis with reverse transcriptase, followed by polymerase chain reaction (PCR). The new assay was compared with the Ortho-Chiron C100-3 HCV enzyme-linked immunosorbent assay to research radioimmunoassays for antibodies to the C33c and C22 HCV antigens and to the first reported set of HCV PCR primers designed from the NS3 domain. Plasma samples from 16 Japanese patients with non-A, non-B hepatitis (NANBH) and 16 immunoassay-positive blood donors from the United States were investigated. The 5PUT PCR primers were found to be superior to the NS3 primers in sensitivity and specificity (15 of 25 versus 3 of 25 of the C100 enzyme-linked immunosorbent assay-positive samples, respectively). Samples from two C100-negative patients with acute NANBH were found to react with the 5PUT primers but not with the NS3 primers. Also, two of three patients with chronic NANBH converted from reverse transcriptase PCR positive to negative after interferon treatment. Although the clinical significance of the presence or absence of HCV RNA in samples from patients is not fully understood, the use of probes and primers from the 5PUT region (as opposed to primers from other segments) should not lead to false-negative results due to nucleic acid sequence variations in viral isolates.

Base Sequence↗