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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 451 records · Page 25Linked to original sources
PubMed1983

Coxsackie B5 myopericarditis in a young adult--clinical course and endomyocardial biopsy findings.

An 18-year-old student with recent gastrointestinal symptoms was found to have Stokes-Adams syndrome. A transvenous pacemaker was successfully inserted with clinical improvement. Subsequent viral titer studies and serum enzyme changes supported the diagnosis of coxsackie B5 myopericarditis. The first cardiac catheterization and endomyocardial biopsy of the right ventricle were performed on the 14th hospital day; the former revealed no hemodynamic abnormalities, but the latter showed marked necrosis of the myofibers, disarray of the remaining ones, mononuclear cell infiltration and the appearance of fibroblasts with fine collagen fiber proliferation in the interstitium. A second biopsy of both ventricles, carried out on the 46th hospital day, showed no necrosis of the myofibers or inflammatory cell infiltration but increasing collagen fiber proliferation in the interstitium and disarray of the surviving myofibers. These pathological findings suggest the healing process of the myopericarditis. To the best of our knowledge, reports of viral myopericarditis with serial endomyocardial biopsies have been few.

Adolescent↗
PubMed1983

[The clinical effects of a new antiviral 9-(2-hydroxyethoxymethyl) guanine (aciclovir) against herpes virus infections].

The clinical effects of a new anti-viral 9-(2-hydroxymethoxymethyl) guanine (Aciclovir) against Herpes virus infections have been investigated. The patients had malignant tumours or auto-immune disease complicated by shingles and chicken pox due to Vaicella zoster virus (VZV) (43 cases), Herpes simplex virus (HSV) (10 cases) and 9 cases which were clinically diagnosed as Herpes, though the virus was not confirmed as the causative agent. As a general principle the dosage of Aciclovir was 5 mg/kg, t. i. d. for 5 days by slow intravenous infusion. The clinically effective rate against VZV was 93%, being excellent in 42% and against HSV it was 80%, being excellent in 40% and when the results of the cases of unknown origin were included it was excellent in 40% and the cumulative effective rate was 88%. Concerning the efficacy in reduction of pain, swelling, disappearance of vesicles and new scab formation, the effect was most noticeable after the third day of treatment. Treatment given early in the disease is likely to provide better results. Concerning side effects, one of 62 patients had proteinuria and the other had a drug rash and an abnormal liver function test. It is likely that the combination of treatment and the primary disease had some influence, but the cause/effect relationship to Aciclovir treatment is not clear.

Acyclovir↗
PubMed1983

[Phase II study with methyl-6[[[2-chloroethyl) nitrosoamino] carbonyl] amino]-6-deoxy-alpha-D-glucopyranoside (MCNU) in hematological malignancies].

A total of 117 cases with hematological malignancies were treated with MCNU at doses of 70-100 mg/m2. Following are the results obtained. 1. MCNU showed a marked depression of cells in the cases with CML, polycythemia vera and thrombocythemia. The low level of cells was maintained for 2 to 7 months. 2. A good response was observed in several cases with blastic crises of CML. 3. No response was observed in two cases with acute leukemia. 4. Although a fair response was observed in several cases with malignant lymphoma or multiple myeloma, moderate bone marrow suppression was observed in a majority of the cases.

Adult↗
PubMed1982

Structure of replication origin of the Escherichia coli K-12 chromosome: the presence of spacer sequences in the ori region carrying information for autonomous replication.

The replication origin region of the Escherichia coli K-12 chromosome has been cloned, and a region of 245 base-pairs has been shown to contain all the information for autonomous replication (defined ori). In order to obtain further information on the sequence organization in the defined ori stretch, various types of mutation were introduced by in vitro techniques at a restriction site (AvaII site) which locates near the middle of ori. When the correlation between these mutations and replicating function was examined, different effects were obtained with the types of mutation: the replicating function was completely destroyed by either insertion or deletion of short sequences, but not by base-substitutions. Based on these observations and on the fact that multi-gene products are involved in the initiation of replication, we assume that two categories of sequences are present within the ori stretch, one specifying interaction with initiation factors (recognition sequences) and the other spacing the recognition sequences in appropriate distances (spacer sequences), and that the AvaII site is located in the spacer region.

Base Composition↗
PubMed1982

Isolation and characterization of an Escherichia coli mutant lacking tRNA-guanine transglycosylase. Function and biosynthesis of queuosine in tRNA.

An E. coli mutant that lacks tRNA-guanine transglycosylase was isolated by random screening from a collection of Escherichia coli mutants obtained with N-methyl-N'-nitro-N-nitrosoguanidine. The defective gene, named tgt, was mapped at about 9 min on the E. coli chromosome, and the gene order was shown to be phoB-tgt-tsx. tgt was transferred to an E. coli strain with a defined genetic background by P1 transduction to investigate its function. The mutant thus obtained lacked queuosine (2-amino-5-[3S, 4R, 5S)-4,5-dihydroxycyclopent-1-en-3-ylaminomethyl]-7-(beta-D-ribofuranosyl)-pyrro lo-[2,3-D]-pyrimidin-4-one) in tRNA, indicating that the enzyme is actually involved in the biosynthesis of queuosine in tRNA. No clear biological defect was observed in the mutant, and, in fact, it grew slightly faster than the control isogenic strain. tRNATyr lacking queuosine, isolated from the mutant, showed no significant biological difference from normal queuosine-containing tRNA in amino acid acceptor activity or amino acid transfer in a cell-free protein synthesizing system directed by synthetic polynucleotide. The only phenotypic change observed in the mutant thus far is marked reduction of viability when the cells are kept under unsuitable conditions for growth, suggesting that the presence of queuosine in tRNA is important to E. coli for survival in the natural environment.

Escherichia coli↗
PubMed1982

Suppressor genes of a dnaA temperature sensitive mutation in Escherichia coli.

Recombinant plasmids were constructed from EcoRI digests of Escherichia coli chromosomal DNA and pMB9 DNA by selecting for suppression of a dnaA-T46 temperature-sensitive mutation. Two types of plasmid capable of suppressing the dnaA mutation were isolated. They did not carry any genetic markers around dnaA and physical mapping with various restriction enzymes showed that neither of the plasmids contained the dnaA gene. One plasmid, pYT47, was characterized further and the protein responsible for the suppression was identified by two-dimensional gel electrophoresis. The molecular weight of the suppressor protein was about 68 Kdal and thus is clearly different from the dnaA gene product.

Bacterial Proteins↗
PubMed1982

Hypertrophic nonobstructive cardiomyopathy: a precise assessment of hemodynamic characteristics and clinical implications.

A precise assessment of left ventricular function was performed in 20 patients with hypertrophic nonobstructive cardiomyopathy to elucidate the basic pathophysiology, and the data were compared with those in 22 normal subjects. Whereas end-diastolic pressure was high in those with cardiomyopathy, a more accurate index of preload, end-diastolic stress, did not differ from normal value. Afterload was about half the normal value. Both isovolumic indexes [peak positive dP/dt and (dP/dt)/DP40] and ejection phase indexes of contractility (ejection fraction) were in the normal range; however, the end-systolic stress volume ratio was significantly reduced (43% of the normal value). Although the left ventricular minute work index was in the normal range, the unit muscle performance (minute work/mass) was very low (49%). An abnormality of left ventricular relaxation was demonstrated by low peak negative dP/dt (56%) and prolonged time constant T (191%), and a stiff left ventricle was demonstrated by a high diastolic elastic stiffness constant (129%). These observations suggest that the contraction of a unit muscle is inappropriate to produce an adequate contraction of the whole ventricle, and that hypertrophy might be an adaptive process to maintain normal systolic function by increasing mass and reducing afterload.

Adult↗
PubMed1982

The relationship of serum uric acid to hypertension and ischemic heart disease in Hisayama population, Japan.

The association of serum uric acid (SUA) with hypertension, ischemic ECG change, diabetes mellitus, and drinking and smoking habits was studied by multivariate analysis among 1871 residents aged 40 and over in Hisayama, Japan. Blood pressure level and history of hypertension did not correlate with an increased level of SUA when other factors such as serum creatinine, obesity, beta-lipoprotein and leucineaminopeptidase were taken into account. Antihypertensive medication was a significant factor influencing SUA. The association of SUA with Minnesota code 4.1-3 (S-T depression) was insignificant in men and significant in women when other factors influencing SUA were taken into account. Glycosuria was negatively correlated with SUA, while alcohol ingestion has positive correlation. There was no correlation between the amount of tobacco smoked and the level of SUA.

Alcohol Drinking↗