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Biomedical subjects

S Mizuno

Publications and source records attributed to S Mizuno.

At least 487 records · Page 27Linked to original sources
PubMed1986

Pharmacokinetics of rectal diazepam in the prevention of recurrent febrile convulsions.

To determine the optimum dosage schedule for intermittent rectal diazepam in suppository form for the prevention of recurrent febrile convulsions, we studied the pharmacokinetics of diazepam administered in repeated rectal doses. The plasma concentration-time data for diazepam on twice repeated rectal dosing with 0.5 mg/kg at 8-hour intervals in six infants showed that therapeutic plasma levels could be attained within 30 minutes and maintained for the first 24 hours. Most of the observed plasma diazepam levels were found to be within +/- one standard deviation of the values calculated from the pharmacokinetic parameters in six other infants with single rectal dosing. Computer-simulated plasma level profile suggested that plasma diazepam levels may reach the toxic range after administration of five or more doses. Twice repeated rectal dosing with 0.5 mg/kg of diazepam in suppository form at 8-hour intervals during the febrile period may be a rational approach for the prevention of recurrent febrile convulsions.

Diazepam↗
PubMed1986

Intrameatal aneurysm.

A case of aneurysm of the anterior inferior cerebellar artery at the internal auditory meatus is presented in which severe subarachnoid haemorrhage was followed by facial palsy. Eighteen cases in the literature are reviewed and their diagnostic and surgical implications discussed.

Arteries↗
PubMed1986

Gamma-interferon production capacity and T lymphocyte subpopulation after allogeneic bone marrow transplantation.

T cell phenotypes after bone marrow transplantation (BMT) were investigated using monoclonal antibodies (moAbs) reactive to lymphocyte cell surface antigens. Patients' T cells showed decreased percentages of OKT4, 4A and 9.3-positive T cells, and increased percentages of OKT8, human Ia, and Leu-7-positive T cells. These changes in T cell phenotype persisted for a long period after BMT and had no correlation with the occurrence of graft-versus-host disease (GVHD). No lymphocyte activation antigens such as TIA (Tac) or transferrin receptor (5E9) were detected after BMT. The capacity of the patients' lymphocytes to produce gamma-interferon (IFN-gamma) was measured after incubation of lymphocytes with mitogen. Patients' lymphocytes produced significantly lower levels of IFN-gamma than the normal controls. This failure of IFN-gamma production showed no correlation with stimulation index of mitogen blastogenesis or changes of T cell population. Thus, not only T cell phenotype but also measurement of IFN-gamma production of lymphocyte may be useful in detecting immunological abnormalities in patients who receive BMT.

Adolescent↗
PubMed1986

Determination of molecular species composition of C80 or longer-chain alpha-mycolic acids in Mycobacterium spp. by gas chromatography-mass spectrometry and mass chromatography.

The molecular species composition of alpha-mycolic acids ranging from C68 to C86 in 13 rapidly growing and 12 slowly growing mycobacterial species was determined by gas chromatography, gas chromatography-mass spectrometry, and mass chromatography. In gas chromatographic analysis, the molecular species of alpha-mycolic acids were well separated as trimethylsilyl ether derivatives of the methyl esters, according to their total carbon numbers. The total carbon and double-bond numbers of mycolic acids at each peak on gas chromatograms were determined from the [M]+, [M - 15]+, and [M - 90]+ ions on the mass spectrum, and straight and branched chain structures were identified by the mass fragment ions [A]+, due to C2--C3 cleavage [R-CH-O-Si(CH3)3]+, and [B]+, due to C3--C4 cleavage [(CH3)3-Si-O-CH-CH(R')-COOCH3]+. The concentration of odd- and even-carbon-numbered mycolic acids, which often overlap each other on gas chromatograms, and the composition of three homologous mycolic acids with different alpha units (C22:0, C24:0, and C26:0) were clearly determined by mass chromatography monitoring [M - 15]+ ions and [B - 29]+ ions, respectively. The molecular species composition of alpha-mycolic acids and their average carbon numbers (av. cn.) as a simple expression of the composition were calculated from the mass chromatograms. Each mycobacterial species examined was demonstrated to possess a characteristic profile of alpha-mycolic acid composition, and based on this the species were classified approximately into eight groups: C68 to C76 (av. cn. 72), dienoic, possessing a C20 alkyl branch at the 2 position (C22 alpha-unit) for Mycobacterium diernhoferi and Mycobacterium sp. strain 3707, a chromogenic rapid grower; C72 to C78 (av. cn. 75), dienoic with both C22 and C24 alpha units, containing a small or a large amount of odd-carbon-numbered molecules, for M. vaccae, M. rhodesiae, and M. phlei (chromogenic rapid growers); C72 to C80 (av. cn. 75 to 77), dienoic with C24 alpha-unit, containing a moderate or a large amount of odd-carbon-numbered molecules, for M. smegmatis, M. chitae, M. chelonae (M. chelonei), and M. fortuitum (nonchromogenic rapid growers); C78 to C82 (av. cn. 80), even-carbon-numbered dienoic with C24 alpha unit for M. agri and M. thermoresistible (rapid growers); C75 to C81 (av. cn. 77 to 79), odd-carbon-numbered dienoic with C24 alpha unit for M. nonchromogenicum complex (M. nonchromogenicum, M. terrae, and "M. novum") (slow growers); (vi) C76 to C84 (av. cn. 79 to 81), even-carbon-numbered dienoic with C24 alpha unit for MAIS complex including M. scrofulaceum, M. avium, and M. intracellulare (slow growers); (vii) C72 to C80 (av. cn. 77 to 79), even-carbon-numbered dienoic with C24 alpha unit for M. szulgai, M. gordonae, and M. kansasii (chromogenic slow growers); and (viii) C76 to C86 (av. cn. 79 to 81), even-carbon-numbered dienoic with C26 alpha unit M. bovis Ravenol and BCG and M. tuberculosis H37Rv. This study demonstrated that gas chromatography-mass spectrometric analysis of the molecular species composition of alpha-mycolic acid can give rapid, important, and very precise information for the identification of pathogenic and nonpathogenic mycobacterial species.

Chromatography, Gas↗
PubMed1986

Role of mandibular striated duct in salivary excretion of urea in dogs.

The role of mandibular striated duct in salivary excretion of endogenous urea was studied by a technique of retrograde ductal injection of HgCl2 and a stop flow analysis. (1) It was verified in this study that treatment with HgCl2 markedly inhibited Na+ reabsorption in the striated duct so that water reabsorption driven by the Na+ reabsorption would be inhibited substantially. (2) The saliva/plasma concentration ratios (S/P ratios) of urea in HgCl2-treated saliva (about 0.71) were significantly higher than those in untreated saliva (about 0.37). (3) The excretion rate of urea in HgCl2-treated saliva (about 0.02 mg/min/kg) was also significantly higher than those in untreated saliva (about 0.01 mg/min/kg) despite the same flow rate for both saliva samples. Furthermore, (4) The S/P ratios of urea in the second (0.25-0.50 ml) poststop-flow saliva (about 0.65) were significantly higher than those in prestop-flow saliva (about 0.35). These results suggest a possibility that salivary urea is reabsorbed in the dog mandibular striated duct and that the enhancement of the S/P ratio as well as the salivary level of urea by the pre-treatment with HgCl2 may be due to the inhibition of urea reabsorption.

Animals↗
PubMed1986

[Washout rate in hypertrophic cardiomyopathy assessed by exercise myocardial scintigraphy].

The present study clarified the pathogenesis of disproportional hypertrophy in terms of disturbed coronary microcirculation. Twenty-eight patients with hypertrophic cardiomyopathy (HCM) who had normal coronary angiograms were categorized in four groups according to distributions of disproportional hypertrophy on left ventriculography and biventriculography: (1) Interventricular septal hypertrophy, (2) septal and apico-anterior wall hypertrophy, (3) apico-anterior hypertrophy, and (4) nonspecific hypertrophy of the entire wall. All 28 HCM patients and 10 normal volunteers were tested using exercise myocardial scintigraphy, and the circumferential profiles were processed by computer to relate the washout rate and disproportional hypertrophy. Comparison of the mean curves and mean segmental values of the circumferential profiles of the HCM groups with those of the control group showed that the mean initial uptake values of the HCM groups were to be relatively low in the apical segment and in the lower portion of the anteroseptal segment representing disproportional hypertrophy of these segments. The mean values were significantly elevated in the upper portion of the anteroseptal segment which was projected as the largest amount of the myocardium three-dimensionally. The mean washout rates in the HCM groups were significantly decreased in all segments, especially in those segments which reflected disproportional hypertrophy. This trend was also observed in the segments with increased initial uptakes. On comparing the segmental values of all groups, the segments with initial uptakes and/or washout rates with having the mean value minus 2SD of the control group were observed in the profiles of 12 of the 28 HCM patients. These all had decreased washout rates. In 25 of the total segments of the HCM patients, the initial uptakes and/or washout rates were below the normal limit; 21 of these segments had only decreased washout rates, and 16 of these 21 segments belonged to disproportionally hypertrophic wall. These results indicate that the decreased washout rate in the disproportionally hypertrophic wall is characteristic of HCM. It is suggested that the decreased washout rate with the decreased initial uptake is caused by disturbance of the coronary microcirculation. In addition, the decreased washout rate without a decreased initial uptake is caused not only by disturbance of coronary microcirculation, but by a metabolic disturbance of the myocardial cells as well. Furthermore, both disturbances are closely related to the pathogenesis of disproportional hypertrophy.

Adult↗
PubMed1986

[Left ventriculography and serial ECG changes in hypertrophic cardiomyopathy with special reference to the negative T wave].

To clarify the correlation between the configuration of the left ventriculogram and serial ECG changes, 16 patients with hypertrophic cardiomyopathy (HCM) associated with asymmetrical septal hypertrophy were examined. In the right oblique view at end-diastole, the configurations were classified by form as round (R, n = 7), round with inferior concavity (R-i, n = 2), spade (S, n = 4) and spade with inferior concavity (S-i, n = 3). These patients were divided into two groups according to serial T wave changes; nine with marked changes (A group) and seven without (B group). Furthermore, group A was separated into two subgroups; seven with increasing negativity or appearance of the negative T wave (A-1 group) and two with decreasing negativity or disappearance of the negative T wave (A-2 group). The results were as follows: Five (71%) of the seven cases with the S and S-i form belonged to the A group. Their apical walls showed marked hypertrophy and their ECGs showed deep negative T waves. The other two cases (29%) belonged to the B group, and did not show marked apical hypertrophy. Four (44%) of the nine cases with the R and R-i form belonged to the A group. They showed mild apical hypertrophy, and initially did not show deep negative T waves. A deep negative T wave appeared in three during observation. The initial depth of the maximum negativity of T wave correlated significantly with apical wall thickness, SV1 + RV5, and the total depth of the negative T wave in precordial leads. During the observation, the A-1 group showed a marked increase of SV1 + RV5. The A-2 group showed a decrease of SV1 + RV5. In conclusion, HCM with deep negative T waves has a tendency to present wide changes in the T wave during serial ECG observation and to show apical hypertrophy on left ventriculography. Cases of increasing negativity of the T wave showed marked increase in voltage of SV1 + RV5. However, cases of decreasing negativity of the T wave showed decreasing SV1 + RV5. These ECG changes, especially the negative T wave changes are reputed to be related to apical wall thickness.

Cardiomyopathy, Hypertrophic↗
PubMed1986

[Biological bases of cancer treatment by hyperthermia].

There is little difference in heat sensitivity in vitro between normal and cancer cells. However, rather selective tumor destruction is induced by in vivo heating without affecting normal tissues. This selective effect may be attributed to heat-induced vascular damage causing reduction in the supply of oxygen and nutrients, and a decrease in the pH of tumors. These cellular environmental changes greatly enhance hyperthermic cytotoxicity. Besides this, antitumor immunity of host animals is also involved in the selective effect of hyperthermia. Hyperthermia potentiated the actions of various antitumor agents including nitrosoureas, cisplatin and bleomycin. The effect of heating on adriamycin cytotoxicity depends on the cell lines used; in some cell lines the cytotoxic effect is enhanced by 42-43 degrees hyperthermia, but in some other cells it is enhanced only at 40-41 degrees and drug-resistance is induced at 43 degrees. Benzaldehyde is nontoxic at 37 degrees but has greatly enhanced cytotoxicity by combination with hyperthermia.

Animals↗
PubMed1986

[Dietary habits among smokers].

Differences in dietary habits between smokers and non-smokers were examined, using the data of well-designed case-control study of colon cancer. Smokers took much more coffee, beef and sake than non-smokers, and smokers tended to take meals irregularly. These dietary habits showed dose-response relationship in the amount of smoking. Odds ratio of proportion of smokers with the above four factors to those without any factors was 10.5, and those with two or three factors were 2-6. These results suggest that the interaction of smoking and dietary habits should be analysed in epidemiological study on cancer.

Adult↗