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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 307 records · Page 17Linked to original sources
PubMed1989

[Evaluation of hepatic function by hepatobiliary scintigraphy using factor analysis].

Factor analysis of hepatobiliary scintigraphy using 99mTc-N-pyridoxyl-5-methyltryptophan (99mTc-PMT) was performed, and functional factor of liver parenchyma (FA-hepatogram) was obtained. Two parameters (peak time, T 1/2) were calculated from this hepatogram. A good correlation was obtained between these parameters and ICG-R15; furthermore, these parameters were prolonged in patients with normal volunteers, chronic hepatitis, compensated and decompensated liver cirrhosis in this order. Conventional hepatogram by ROI method (ROI-hepatogram) was not suitable for the evaluation of global liver function in condition such as a large intrahepatic mass, intrahepatic gall bladder, dilatation of biliary tree, and severe liver cirrhosis. But, even in such cases, FA-hepatogram was useful for the evaluation of global liver function.

Biliary Tract↗
PubMed1989

[Paroxysmal cold hemoglobinuria complicated with acute hemolysis in a child].

An 8 year-old girl with paroxsmal cold hemoglogunuria (PCH) is reported. She was referred to our clinic because of acute anemia, and found to have PCH after clinical and laboratory examination. Anti-P1 antibody and Donath-Landsteiner (D-L) antibody were detected. In Coombs' test with variable incubation temperatures, positive IgG on her erythrocytes changed to negative as temperature of incubation was elevated. Also activation of complement was detected on the surface of her erythrocytes. Clinical improvement was obtained by blood transfusion, and positive Coomb's test and D-L test turned to negative.

Acute Disease↗
PubMed1989

Effect of spatial resolution on SPECT quantification values.

The effect of spatial resolution on quantification by single photon emission computed tomography (SPECT) was studied using a rotating gamma camera and 99mTc. Using phantoms with hot and cold regions, experiments were performed to ascertain relationships between the source and the SPECT image, and to compare them with theoretic calculations. According to the results, the SPECT value represented the true radioactivity when the objects' sizes were 2.5 times larger than full width at half maximum (FWHM) for hot regions. For cold regions, there were errors of approximately 20% for the true value, even in the case of such large sizes. In addition, sizes at half maximum images corresponded to true object sizes when hot region sizes were larger than 1.4 x FWHM. The relationship between absolute radioactivity and total SPECT value was linear when the threshold level was zero. Knowing the effect of spatial resolution is a necessity in clinical SPECT studies.

Models, Structural↗
PubMed1989

Efficacy of coronary artery bypass surgery with gastroepiploic artery. Assessment with thallium 201 myocardial scintigraphy.

This study describes the efficacy of the right gastroepiploic artery (GEA) as graft material for coronary artery bypass grafting (CABG) as assessed by exercise thallium 201 myocardial scintigraphy in eight patients (age, 59.4 +/- 9.35 years [mean +/- SD]) who underwent CABG with the GEA graft in the past 2 years. Planar and single-photon-emission computed tomographic (SPECT) images were obtained during and 3 hours after exercise. Planar images were evaluated quantitatively with the percentile-washout method, and SPECT images were evaluated qualitatively with a bull's-eye, polar-coordinate map. All patients had triple-vessel disease, and in situ GEAs were anastomosed to the right coronary artery in seven patients and to the left anterior descending coronary artery in one. The internal mammary artery graft was concomitantly used in all patients. The mean number of grafts per patient was 3.0 (range, 2-4). Preoperative exercise testing could not be performed in two patients because of emergency operation. By qualitative assessment with the polar-coordinate map, four patients showed improvement, one did not show any change, and one became worse due to perioperative myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Prevalence and clinical significance of development of conduction disturbances in patients with hypertrophic cardiomyopathy].

To clarify the prognostic significance of electrocardiographic changes in hypertrophic cardiomyopathy, we retrospectively evaluated serial electrocardiograms of 77 patients with hypertrophic cardiomyopathy who were followed more than one year. Conduction disturbance was analyzed as an electrocardiographic feature. Excluding four cases of sudden death, various conduction disturbances developed in 32 of the 73 patients. Intraventricular conduction delay was the most frequent among them (47%). Left ventricular end-diastolic pressure at the initial investigation was significantly higher, and clinical deterioration developed more frequently in patients with conduction disturbances, as compared with those without conduction disturbances. Histopathological analyses showed that proliferation of collagen fibers in the left ventricle was frequently associated with conduction disturbances. However, the electrocardiographic changes did not develop in the four patients who died suddenly. It was concluded that conduction disturbances comprise a significant parameter suggestive of poor prognoses in patients with hypertrophic cardiomyopathy, but that they are not predictors of sudden death.

Adolescent↗
PubMed1989

Direct inhibitory ovarian effects of prolactin in the process of ovulation.

The present study was designed to determine the effects of prolactin (PRL) on the process of follicle rupture and oocyte maturation using an in vitro perfused rabbit ovary model. In the first experiment ovaries were perfused for 12 hours with or without PRL at 10(2) or 10(3) ng/ml. Ovulation did not occur in any ovaries in the absence of gonadotropin. The majority of follicular oocytes did not progress beyond the germinal vesicle stage following treatment with PRL. The percentage of follicular oocytes which showed evidence of degeneration was also comparable in both groups. The concentrations of progesterone in the perfusate did not differ significantly between PRL-treated and control ovaries. In the second experiment, ovaries were perfused with or without PRL at 10, 10(2), or 10(3) ng/ml. Thirty minutes later 50 IU of human chorionic gonadotropin (hCG) was added to the perfusate of all ovaries. The addition of PRL to the perfusate inhibited hCG-induced ovulation in a dose-related fashion. The degree of ovum maturity and degeneration was comparable in the two groups. PRL did not affect hCG-stimulated progesterone production by the perfused rabbit ovaries. The present study demonstrates that PRL acts directly on the ovary to influence the process of ovulation, resulting in the inhibition of hCG-induced follicle rupture. These data suggest that PRL inhibits ovulation by mechanism(s) independent of ovarian progesterone synthesis.

Animals↗
PubMed1988

Augmentation of coronary bypass graft flow induced by dipyridamole and its relation to bypass graft patency.

To evaluate the effect of dipyridamole on coronary bypass graft flow, 10 mg of dipyridamole was injected intravenously, during the measurement of graft flow, at the time of surgery. Its concentration in serum was measured and compared with that after oral administration. In 50 individual vein grafts performed on 35 patients, graft flow increased from 65 +/- 37 to 96 +/- 55 ml/min (p less than 0.001) after the dipyridamole injection and the arterial pressure decreased slightly. In 40 grafts whose graft flow was increased by more than 10 ml/min by dipyridamole, the patency rate (at 5 weeks) was 98 per cent, whereas that of the 10 other grafts, which responded poorly, was only 50 per cent (p less than 0.01). The serum concentration of dipyridamole, 3 minutes after intravenous injection, was 1.46 +/- 0.68 micrograms/ml, while the level of orally administered dipyridamole, in 3 groups of patients who were given 50 mg, 75 mg and 100 mg, three times a day, respectively, was steady, being 0.68 +/- 0.20 micrograms/ml, 1.43 +/- 0.41 micrograms/ml and 1.73 +/- 0.50 micrograms/ml, 2 hours following ingestion. We concluded that intravenous dipyridamole increases the graft flow and that a better patency is obtained in those grafts in which the graft flow is increased by more than 10 ml/min. It is also expected that routine doses of oral dipyridamole possibly increase the graft flow after coronary bypass surgery.

Administration, Oral↗
PubMed1988

Prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in apparently healthy subjects: a prospective study in the general population.

The prevalence of left ventricular false tendons, premature ventricular complexes and their coexistence was evaluated prospectively in 187 healthy company workers aged 21 to 50 (mean 36) years. False tendons were demonstrated echocardiographically in 133 (71%). Eight subjects were withdrawn from the study because of silent mitral valve prolapse. In these 179 healthy subjects, false tendons were detected in 127 (71%) and premature ventricular complexes in 48 (27%). Their coexistence was observed in 40, which showed a significant correlation (p less than 0.05) of false tendons and premature ventricular complexes. In seven of the eight subjects without false tendons, premature ventricular complexes were uniform and infrequent (mean 3 beats/24 h). In the 40 subjects with false tendons, premature ventricular complexes were uniform in 29, multiform in 6 and repetitive in 5, and the mean frequency was 96 beats/24 h. Correlation of premature ventricular complexes with the type of false tendons showed that premature ventricular complexes were significantly associated with thick (greater than or equal to 2 mm) and longitudinal tendons (p less than 0.005). Although it is not certain that left ventricular false tendons are arrhythmogenic, the prevalence of the coexistence of left ventricular false tendons and premature ventricular complexes in the general population, and the special relation between the frequency and the form of premature ventricular complexes and the type of false tendons, suggests that false tendons may play an etiologic role in the genesis of premature ventricular complexes in apparently healthy subjects.

Adult↗
PubMed1988

Angiotensin-converting enzyme and anorexia nervosa.

Angiotensin-converting enzyme (ACE) activity was measured in 10 patients with anorexia nervosa, 6 with hyperthyroid Graves' disease, and 7 with primary hypothyroidism. Patients with anorexia nervosa had a low serum ACE activity (9.8 +/- 2.2 IU/l), as compared to findings in normal subjects (13.4 +/- 3.5 IU/l) (P less than 0.05). Patients with hyperthyroid Graves' disease had high serum ACE activity (23.7 +/- 5.8 IU/l), as compared to levels in normal subjects (P less than 0.01), and patients with primary hypothyroidism tended to have low serum ACE activity (10.1 +/- 1.8 IU/l), compared to the normal subjects (P less than 0.1). Following weight gain (before; 71.3 +/- 10.2% of ideal body weight, after; 88.7 +/- 5.6% of ideal body weight), serum ACE activity in patients with anorexia nervosa reverted to within the normal range (13.8 +/- 3.5 IU/l), and serum T3 concentration was restored to the normal range (before; 0.7 +/- 0.2 ng/ml, after; 1.1 +/- 0.3 ng/ml). In these patients, ACE activity correlated with the per cent of ideal body weight (P less than 0.05). These data suggest that, in underweight subjects with anorexia nervosa, decreased serum ACE activities may relate to emaciation.

Adolescent↗
PubMed1988

Overexpression, solubilization and refolding of a genetically engineered derivative of the penicillin-binding protein 3 of Escherichia coli K12.

Replacement of the amino-terminal 40-amino-acid region of the 588-amino-acid precursor of the membrane-bound penicillin-binding protein 3 (PBP3) by the decapeptide MKGKEFQAWI was carried out by altering the amino-coding end of the ftsI gene. Insertion of the modified gene into a runaway-replication plasmid under the control of a fused lpp promoter and lac promoter/operator, resulted in the overexpression by Escherichia coli of the modified PBP3 (designated PBP3**) in the cytoplasm. About 80% of the accumulated PBP3** underwent sequestration in the form of insoluble protein granules that were isolated by cell breakage or cell lysis. After selective removal of contaminants by an EDTA-lysozyme/DNase (deoxyribonuclease)/Nonidet extraction, treatment of the granules with guanidinium chloride followed by dialysis against buffer containing 0.5 M NaCl yielded a refolded, water-soluble PBP3**, which, upon chromatography on Superose 12, exhibited the expected 60,000 molecular mass. The refolded PBP3** bound benzylpenicillin in a 1 to 1 molar ratio, was highly sensitive to aztreonam and showed the same degree of thermostability, in terms of penicillin-binding capacity, as the parent, membrane-bound PBP3, suggesting that protein refolding occurred with formation of the correct intramolecular interactions. Two to three mg of refolded PBP3** can be obtained from 1 litre of culture of the overproducing strain.

Acyltransferases↗
PubMed1988

Haematopoiesis in the aged as studied by in vitro colony assay.

Changes occurring in human haematopoiesis with advancing age were studied using an in vitro haematopoietic colony assay in 22 elderly subjects with unexplained anaemia, and in 15 elderly and 15 young subjects without anaemia. Both elderly groups were found to have significantly lower numbers of bone marrow early erythroid-committed progenitors (BFU-E) than the young controls. The elderly anaemic group also showed significantly lower numbers of granulocyte/macrophage progenitors (CFU-GM) than the young controls. However, the responses of the erythroid-committed progenitors in the elderly groups to erythropoietin and burst-promoting activity were similar to those observed in the young controls. Therefore, it is probable that anaemia tends to occur easily in elderly individuals as a result of reduction of reserves of haematopoietic progenitors with advancing age.

Adult↗
PubMed1988

Lipid modification of Escherichia coli penicillin-binding protein 3.

The primary structure of penicillin-binding protein 3 (PBP 3), an essential enzyme for cell division in Escherichia coli, was deduced from the nucleotide sequence of the ftsI gene (M. Nakamura, I. N. Maruyama, M. Soma, J. Kato, H. Suzuki, and Y. Hirota, Mol. Gen. Genet. 191:1-9, 1983). An amino acid sequence of Leu-26-Leu-Cys-Gly-Cys-30 was found near the amino terminus of the deduced sequence, showing a rather striking homology to the Leu-Leu-Ala-Gly-Cys consensus sequence for the modification and processing of precursors of the E. coli murein lipoprotein and other bacterial lipoproteins. As expected from this finding, PBP 3 was found to be modified with glycerol and fatty acids, although the lipid modification occurred only in a small fraction, accounting for less than 15% of the total PBP 3 molecules.

Acyltransferases↗
PubMed1988

Gene organization in the region containing a new gene involved in chromosome partition in Escherichia coli.

A new mutation, parC, causing abnormal chromosome segregation was identified in two thermosensitive mutants of Escherichia coli. The thermosensitive growth of the mutants was corrected by pLC4-14 in the Clarke-Carbon collection. This plasmid carries a putative gene which can suppress the cell division defect due to ftsI (pbpB) and has hence been termed sufI (sui). The nearness of parC to metC was confirmed, and cotransduction frequency of parC was 59% with metC and 20% with glc. The parC-sufI region was analyzed by subcloning the chromosome region of pLC4-14. The parC and the sufI gene products were electrophoretically identified as proteins of 75 and 55 kilodaltons (kDa), respectively. The allelism of parC+ on pLC4-14 to parC1215 was confirmed by cloning parC1215. The sufI gene appeared to be dispensable for cell viability, and overproduction of its product caused suppression of ftsI. An essential gene coding for a 25-kDa protein was found between the parC and the sufI gene. These three genes were transcribed in the same direction and may be organized into an operon, with parC to the proximal side and with internal promoters at least for the distal genes. The localization of the gene products was examined in maxicells. The sufI protein was synthesized as a precursor which could be chased into a mature form. The major part of the mature form was found in the soluble fraction. The 25-kDa protein was found almost exclusively in the membrane fraction. The parC protein was associated with the membrane fraction in the presence of Mg2+ but found in the soluble fraction when Mg2+ was sequestered with EDTA.

Bacterial Proteins↗
PubMed1988

Substitution of Ser-17 of pp60c-src: biological and biochemical characterization in chicken embryo fibroblasts.

pp60c-src is phosphorylated mainly on Ser-17 and Tyr-527 in vivo. In this study, we examined the effect of the phosphorylation of Ser-17 on the properties of pp60c-src by introducing Rous sarcoma virus variants carrying pp60c-src in which Ser-17 had been substituted, into chicken embryo fibroblasts. The Ala-17 substitution in wild-type pp60c-src and pp60c-src carrying Phe-527 caused a two- to threefold elevation in the kinase activity in vitro of these proteins; the former variant resulted in no morphological changes of infected cells, whereas the latter variant transformed chicken embryo fibroblasts. Since the substitution of Tyr-527 per se has been reported to activate pp60c-src, these results suggest that the abolishment of the phosphorylation of Ser-17 does not affect noticeably the properties of pp60c-src in chicken embryo fibroblasts.

Animals↗
PubMed1988

A case of Candida albicans skin abscess associated with intravenous catheterization.

We report a case of Candida albicans skin abscess, which developed on the left knee of a 59-year-old male, who had been bedridden for the past 2 months because of subarachnoid haemorrhage. The route of the infection was considered to be an intravenous catheter that had been inserted into the left great saphenous vein at the medial malleolus. The prolonged systemic administration of antibiotics and corticosteroids, as well as prostration, were suspected to be the factors that led to the infection. The patient was successfully treated with intravenous miconazole and subsequent high-dose oral amphotericin B therapy.

Abscess↗
PubMed1988

Coronary artery bypass grafting by utilizing the internal mammary artery graft in 100 Japanese patients.

The internal mammary artery (IMA) grafting for myocardial revascularization was performed in 100 Japanese patients during a three-year period. There were 86 males and 14 females with the mean age of 58 +/- 9 (37 approximately 75 year-old). Unilateral IMA was used in 88 patients and bilateral IMA was used in 12 patients. Sequential IMA grafting was performed in 5 patients. The sites of IMA grafting were 91 left anterior descending arteries (LAD), 16 diagonal branches, 8 circumflex arteries and 2 right coronary arteries. Saphenous vein or gastroepiploic artery was concomitantly used to bypass the other coronary arteries in 90 patients. The number of distal anastomosis ranged from 1 to 6 and the mean was 2.8 per patient. Two patients died within 30 days and one patient died at 3 months after surgery. Perioperative myocardial infarction was noted in 3 patients. Symptomatic relief was obtained in 94 (97%) of 97 survivors. The patency of the IMA graft at mean 2.2 postoperative months was 97% (58/60) in LAD, 100% (14/14) in the diagonal branch, 100% (5/5) in the circumflex artery, 100% (1/1) in the right coronary artery, and 98% (78/80) in over-all grafted coronary arteries. Pre- and postoperative exercise thallium scintigraphy in 13 patients, who received the IMA graft to severely stenosed LAD, showed significant improvement of the washout ratio (from 33.1 +/- 16.9% to 47.4 +/- 14.8%) which was nearly equivalent to that of the saphenous vein graft to LAD (from 24.8 +/- 6.2% to 48.1 +/- 6.6%, n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗