PubMed Health⌕ Search

Biomedical subjects

S Komura

Publications and source records attributed to S Komura.

At least 19 recordsLinked to original sources
PubMed1992

Generation of hydroxyl radical from linoleic acid hydroperoxide in the presence of epinephrine and iron.

When linoleic acid hydroperoxide was reacted with ferrous iron, the electron spin resonance signals characteristic of the spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide and the hydroxyl radical were detected. Although the signals were not detected with the hydroperoxide and ferric iron, they were actually found if epinephrine was added, indicating that the hydroxyl radical could be generated from the hydroperoxide upon reduction of the latter with ferrous iron formed by epinephrine. The possible generation of the hydroxyl radical from lipid peroxides in vivo was discussed from the viewpoint of pathogenesis of lipid peroxide-related diseases.

Cyclic N-Oxides↗
PubMed1992

Pathological study of diffuse axonal injury patients who died shortly after impact.

It is generally considered that axonal injury is apparent only on electron microscopy in the very early stage after a closed head injury. To clarify the pathological findings in head injury patients dying very shortly after the impact, we analyzed 8 fatal cases of diffuse axonal injury (DAI) who underwent medicolegal autopsy at the Department of Forensic Medicine of Kyoto Prefectural University of Medicine. Seven cases died within one hour after injury and another one case died 3 days after injury. We studied these cases macroscopically, microscopically, and electron microscopically. Macroscopically all cases showed the typical findings of diffuse axonal injury. Microscopical study of the cases who died within one hour revealed no characteristic findings of DAI such as appearance of retraction balls or microglia. On the other hand, in the case who died only 3 days after injury it showed the typical retraction balls. Electron microscopic study showed the remarkable destruction of cytoskeletal structure of axons in all cases. From our results, it is reasonable to speculate that DAI may be common among head injury patients who die very soon after the impact.

Adolescent↗
PubMed1992

[Trace analysis for drugs and poisons in human tissues].

Despite continuous developments of analytical techniques in terms of sensitivity and accuracy, uncountable increase in number of chemical substances are brought into the field of forensic sciences to be analyzed. Based on the idea that progress in analytical technique to cope with the change of situation is always required, a research team including 10 members was organized to set up the most advanced methods at present to analyze the important drugs and poisons in biological materials for forensic purposes. Stimulant drugs such as methamphetamine and amphetamine were studied on the improvement of extraction procedure prior to mass spectrometric analysis. A conventional solvent extraction method was replaced by an extraction technique using Extrelut column. The technical procedure was simplified and the accuracy of measurement was improved. The changes in CO-Hb concentration in the whole blood in storage was examined with regard to the lapse of time and temperature, where a differential spectrophotometry was used. Useful information could be obtained from practical aspects. Analytical conditions of gas chromatography were revised on volatiles including alcohols, especially as to column conditions. The use of capillary column was recommended for sensitivity and peak separation. The optimum conditions for detecting barbiturates in the blood were examined. The combination of Sep-pak C18 cartridge with a capillary column for gas chromatography using nitrogen phosphorus detection was found preferable. Mass spectrometry of various kinds of local anesthetics was studied. Quantitative analysis of the drugs was examined on gas chromatography with a surface ionization detector. Three types of insecticides including organophosphorus, chlorinated and fluorine compounds were analyzed by gas chromatography/mass spectrometry in order to establish a sensitive and selective method. The detection limits, calibration and reproducibility were examined. Herbicide, paraquat, was examined on the sensitivity, recovery, required time and costs in connection with methods of pretreatment and analytical procedure. A secondary spectrophotometry was found useful practically. Antimony in biological tissues was analyzed, using a flameless atomic absorption spectrometer with carbon tube atomizer. The time for analysis was reduced, and sensitivity was improved. Immunoassay method was examined from general aspects on drugs and hormones. Using antibodies specific to haptens, the dynamics of such antigens as drugs and hormones in the body tissues were observed. Interfering substances at the time of toxicological analysis were checked in order to obtain reliable information. Exact identification was found possible by using gas chromatography/mass spectrometry. As described above, the research was made from the practical aspects of forensic toxicology, and meaningful results could be obtained from each study.

Animals↗
PubMed1992

Legislation on alcohol detection in alcohol-related traffic accidents involving casualties in Japan and Canada.

A comparative study of the law concerning the arrest and conviction of alcohol-related casualty traffic accident was made between Japan and Canada. In Japan, the incidence of alcohol-related traffic accident has declined since 1970, but the number of fatal traffic accidents remains unchanged over the last 6 years, and amount to 9% of the total number of fatalities in traffic accidents. Hence, an effort is being made to reduce this number. According to the Road Traffic Act, a driver can be convicted for drunken driving if his or her blood alcohol level is above 0.5 mg/ml or above 0.25 mg/l in exhaled air, and if driver is judged as a drunken state by sobriety test. Unlike Canada, however, police officer cannot demand a blood sample from a suspected drunken driver. Instead, they must rely on the breath analysis and sobriety test. These tests are considered to be less accurate than blood test. These drawbacks are reflected in a number of court cases which are related to the relationship between alcohol concentration and the state of driving. In Canada, the operation of a motor vehicle with a blood alcohol level of over 0.8 mg/ml is a criminal offense punishable by fine or imprisonment or both, and results in the suspension of driving privileges for 6 months. Initially, a breath alcohol analysis is performed on everyone suspected of motor vehicle after consuming alcohol within the preceding two hours. Subsequently, with the suspect's consent, a police officer is allowed to request a blood sample for further analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1992

Occurrence in vivo of 5-hydroxytryptophol in the brain of rats treated with ethanol.

The effect of ethanol (EtOH) on the release of dopamine (DA) and 5-hydroxytryptamine (5-HT) and the efflux of their metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindol-3-ylacetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL) from the striatum of the freely moving rat were studied in vivo using brain microdialysis. Striatal DA and 5-HT release was maximally enhanced at first fraction after the administration of EtOH (2 g/kg, i.p.). The level of the DA-oxidized metabolite, DOPAC, decreased significantly. In the 5-HT metabolic pathway, the oxidized metabolite, 5-HIAA, did not show significant changes, whereas levels of the biogenic alcohol 5-HTOL were increased to 180% at 90 min following EtOH administration. It is suggested that EtOH, most probably via acetaldehyde, could shift 5-HT metabolism from the oxidative to the reductive pathway in the rat brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

[Alcohol drinking behaviors--physiological and sociomedical factors].

Alcohol drinking behavior is usually studied from two perspectives, factors leading to drinking behavior and the behavioral effects of alcohol drinking. Many detailed medicolegal, pharmacological and psychiatric studies have been conducted on the behavioral effects of alcohol drinking. Few studies have considered the biological aspects of a desire for alcohol. However, these issues can not be ignored. The role of genetic, environmental and nutritional factors in alcohol preference has extensively debated. Recently, biochemical, physiological and pharmacological studies have also been performed to elucidate the mechanism of the desire for alcohol. In this study, the biological aspects of drinking behavior and alcohol preference have been studied using inbred strains of mice as an animal model on alcoholism. In addition, factors affecting drinking behavior of human beings are discussed based on the results obtained from a medico-legal study of alcohol-related cases. 1. Alcohol preference in several animal species The alcohol preference expressed as a ratio (%) of the volume taken (water and 10% (v/v) alcohol solution), was not constant in several animal species. The preference ratio was observed to be 2.7 +/- 0.7, 3.7 +/- 0.8, 22.0 +/- 19.8 and 39.6 +/- 5.4 in male inbred strains of SAMP2, DBA/2cr, B10.Br/Sg and C57BL/6J mice respectively, and 10.7 +/- 7.6, 15.9 +/- 13.6, 31.3 +/- 22.6 and 32.4 +/- 16.7 in male Donryu, DA, Wistar and Buffalo rats respectively, and 91.3 +/- 9.1 in male Golden hamster, and 2.1 +/- 0.3 in Hartley guinea pigs. Rabbits and Japanese monkeys do not demonstrate high alcohol preference. By comparison, the alcohol preference of a Japanese people was estimated to be approximately 11-35% on the basis of data obtained by questionnaire. 2. Development of alcohol dependence and withdrawal by voluntary alcohol intake in mice Eight strains of male mice, C57BL, C3H, SWM, SW, KK, KSB, KR and DBA, were offered a choice of water or 10% sake solution (sake containing 10% alcohol). Both young (3 months of age) and old (8 months of age) groups were studied simultaneously. The degree of intoxication was measured by recording the drinking behavior on a pulse recorder, by measuring gas-chromatographically the blood alcohol concentration, by taking depth electroencephalogram readings and so on. Intoxication, shown by lack of coordination such as grossly impaired gait, was observed only in the older mice of a strain with a moderate natural alcohol preference such as C3H, SWM, SW, KK and KSB.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗
PubMed1989

Buthionine sulfoximine inhibition of glutathione biosynthesis enhances hepatic lipid peroxidation in rats during acute ethanol intoxication.

A single intraperitoneal injection of DL-buthionine-S,R-sulfoximine (BSO) (4 mmol/kg) to overnight-starved rats caused a 70% inhibition of hepatic gamma-glutamylcysteine synthetase and induced a decrease in liver-reduced glutathione (GSH) for several hours. There was, however, no difference in hepatic lipid peroxidation, as assessed by malondialdehyde accumulation, between the control and BSO groups. During acute ethanol intoxication (5 g/kg), hepatic lipid peroxidation was increased by approx. 40% within 6 hr. Hepatic [GSH] was also significantly decreased by ethanol. The effect of ethanol on GSH level was not observed in rats pretreated with BSO, though the ethanol-induced enhancement of hepatic lipid peroxidation was potentiated by the BSO pretreatment. Under these conditions there were no apparent effects on blood concentrations of ethanol and acetaldehyde nor on activities of hepatic alcohol dehydrogenase, aldehyde dehydrogenase, glutathione-dependent detoxifying enzymes, superoxide dismutase or catalase. These results suggest that, although a decrease (by BSO) in GSH by itself does not alter the degree of endogenous lipid peroxidation, it is associated with a potentiation of the enhancement of hepatic lipid peroxidation caused by acute ethanol intoxication.

Alcoholic Intoxication↗
PubMed1989

Genetic differences in the effects of voluntary ethanol consumption on brain monoamine levels in inbred strains of mice, C57BL/6J, C3H/He and DBA/2Cr.

This study was carried out to determine whether concentrations of the brain monoamines noradrenaline (NA), dopamine (DA), and 5-hydroxytryptamine or serotonin (5-HT) are different in three inbred strains of mice (C57BL/6J, C3H/He and DBA/2Cr) known to differ in their preference to alcohol, when they were given a free choice of 10% (v/v) ethanol and tap water to drink for 4 weeks. Mice of these three strains showed mean ethanol intakes of 4.41, 1.76 and 0.77 g/kg/day respectively. Levels of the above brain monoamines did not change in the alcohol-preferring C57BL/6J mice, but in those with less preference for alcohol, C3H/He and DBA/2Cr, there were significant increases in DA and 5-HT levels respectively during the 4-week experiment. These findings suggest that inbred strains of mice show genetic differences of susceptibility to ethanol and that the strains with a low preference for alcohol undergo neurochemical changes after exposure to 10% ethanol and water even by free choice.

Alcohol Drinking↗
PubMed1988

Purification and characterization of a novel monomeric glutathione peroxidase from rat liver.

A novel glutathione peroxidase, which is active toward hydroperoxides of phospholipid in the presence of a detergent, has been purified to homogeneity from a rat liver postmicrosomal supernatant fraction by ammonium sulfate fractionation and three different column chromatographies. From a DE52 column, glutathione peroxidase active toward phosphatidylcholine dilinoleoyl hydroperoxides was eluted in one major and two minor peaks. The enzyme in the major peak was found to be separated from the "classic" glutathione peroxidase and glutathione S-transferases and further purified by Sephacryl S-200 and Mono Q column chromatographies. The purified enzyme was found to be homogeneous on polyacrylamide gel electrophoresis under nondenaturing conditions as well as that in the presence of sodium dodecyl sulfate. The molecular weight of the enzyme as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 22,000, and that by gel filtration was comparable, indicating that the enzyme protein is a single polypeptide. The purified enzyme was found to catalyze the reduction of phosphatidylcholine dilinoleoyl hydroperoxides to the corresponding hydroxy derivatives. The isoelectric point of the enzyme was found at pH 6.2, and the optimum pH for the enzyme activity was 8.0. The enzyme was active toward cumene hydroperoxide, H2O2, and 1-monolinolein hydroperoxides in the absence of a detergent. The enzyme activity toward phospholipid hydroperoxides was minute in the absence of a detergent but was remarkably enhanced by the addition of a detergent. From these results, the presently purified enzyme is obviously different from the classic glutathione peroxidase and also from phospholipid hydroperoxide glutathione peroxidase purified from pig heart (Ursini, F., Maiorino, M., and Gregolin, C. (1985) Biochim. Biophys. Acta 839, 62-70), though considerably similar to the latter.

Animals↗
PubMed1988

The metabolism of acetaldehyde and not acetaldehyde itself is responsible for in vivo ethanol-induced lipid peroxidation in rats.

A single oral administration of ethanol (5 g/kg) to rats induced a marked increase in lipid peroxidation, in the liver and kidney within 9 hr, as assessed by malondialdehyde accumulation. The pretreatment with alcohol dehydrogenase (ADH) inhibitor, 4-methylpyrazole (1 mmol/kg) caused approximately 50% inhibition of the hepatic ADH activity and abolished this ethanol-induced lipid peroxidation. The disulfiram treatment (100 mg/kg) significantly inhibited 63% of the hepatic low Km aldehyde dehydrogenase (ALDH) but not the high Km ALDH. The cyanamide treatment (15 mg/kg) effectively decreased 83% of the low Km and 70% of the high Km ALDH in the liver. Although there was more than a 20-fold elevation of acetaldehyde levels by the inhibition of acetaldehyde metabolism with disulfiram or cyanamide, the ethanol-induced lipid peroxidation was significantly suppressed by pretreatment with these drugs. More than 90% inhibition of xanthine oxidase and dehydrogenase by the pretreatment with allopurinol (100 mg/kg), with no effect on the hepatic ADH and ALDH activities, did not alter the enhancement of lipid peroxidation following ethanol administration. We propose that the metabolism of acetaldehyde (probably via the low Km ALDH) and not acetaldehyde itself is responsible for the ethanol-induced lipid peroxidation in vivo and that the contribution of xanthine oxidase, as an initiator of lipid peroxidation through acetaldehyde oxidation is minute during acute intoxication.

Acetaldehyde↗
PubMed1987

Reexamination of the relationship between alcohol preference and brain monoamines in inbred strains of mice including senescence-accelerated mice.

The relationship between voluntary alcohol consumption and brain monoamine levels was studied in the inbred strains of C57BL/6N, C57BL/6J, A/J, BALB/cA, CBA/N, C3H/He and DBA/2cr mice; the congeneric mouse strain, B10.Br/Sg, and the senescence accelerated mouse (SAM P1, SAM P2). The C57BL strains exhibited a high alcohol preference whereas the other strains exhibited a low alcohol preference. A clear positive relationship was found between alcohol intake (g/kg/day) and brain norepinephrine level (r = 0.683, p less than 0.05), and a clear negative relationship between alcohol intake and brain serotonin level (r = -0.628, p less than 0.05). The content of brain dopamine was not clearly correlated with alcohol intake (r = -0.206, p greater than 0.05). These findings suggest that in mice voluntary alcohol preference is influenced by brain norepinephrine and serotonin levels genetically.

Alcohol Drinking↗
PubMed1986

Serum lipid peroxide levels of albino rats administered naphthalene.

When naphthalene was administered at a daily dose of 1 g/kg body weight to Wistar strain rats, their serum lipid peroxide levels were increased on the 4th day after the first administration and reached a maximum on the 7th day. This seems to be due to lipid peroxidation in the liver, in which lipid peroxide levels were increased in a similar pattern as those in the serum. The content of reduced glutathione in lenses of naphthalene-administered rats decreased on the 4th day. These results suggest that in naphthalene-induced cataract in albino rats increased lipid peroxides in the bloodstream may play a role in cataractogenesis.

Animals↗
PubMed1986

Inhibitory effect of female hormones on lipid peroxidation.

The female hormones estradiol, estrone, and estriol acted as antioxidants in the peroxidation of methyl linoleate by UV irradiation. All of them inhibited the peroxidation of microsomal lipids when they were added to the ADP-Fe3+ peroxidation system of rat liver microsomes. The efficiencies in the microsomal system were in the order of estradiol greater than estriol greater than estrone.

Animals↗
PubMed1985

Conjugation of acetaldehyde with cysteinylglycine, the first metabolite in glutathione breakdown by gamma-glutamyltranspeptidase.

Glutathione and its metabolites were examined for reactivity to acetaldehyde. When acetaldehyde was incubated with glutathione alone, there was only a slight decrease of acetaldehyde, while an apparently equimolar reaction between acetaldehyde and free sulfhydryl was observed with the addition of gamma-glutamyltranspeptidase. Cysteinylglycine, the first metabolite in the glutathione breakdown by gamma-glutamyltranspeptidase, showed a rapid and equimolar reactivity to acetaldehyde and such was comparable to the reaction seen with L-cysteine or D-penicillamine. In light of the chemical structure, cysteinylglycine probably conjugates with acetaldehyde to form thiazolidinecarboxylic acid derivatives, 2-methyl-thiazolidine-4-carbonyl-glycine, and if so, the alteration of glutathione metabolism by acetaldehyde during ethanol intoxication warrants further attention.

Acetaldehyde↗
PubMed1985

Biosynthesis of polymyxin E by a cell-free enzyme system. IV. Acylation of enzyme-bound L-2,4-diaminobutyric acid.

An enzyme fraction, which catalyzes the ATP-PPi exchange reaction dependent on the three constituent amino acids of polymyxin E, was partially purified from crude extracts of Aerobacillus polyaerogenes. The approximate molecular weight was estimated to be 640,000 by Sepharose 4B gel filtration. Incubation of the enzyme with octanoyl coenzyme A and diaminobutyric acid in the presence of ATP and an ammonium sulfate fraction yielded octanoyldiaminobutyric acid thioesterified to the enzyme protein. On mild alkali treatment, octanoyldiaminobutyric acid, identified by paper chromatography, was released from the enzyme protein. From its acid hydrolyzate, diaminobutyric acid and octanoic acid were recovered in a molar ratio of 1 to 0.7. An ammonium sulfate fraction was required as the source of an acyltransferase for acylation of the enzyme-bound diaminobutyric acid. When [14C]-threonine was incubated with L-2,4-diaminobutyric acid in the presence of octanoyl coenzyme A, octanoyldiaminobutyrylthreonine bound to the enzyme protein was formed. These results suggest that acyldiaminobutyric acid bound to the enzyme protein is a possible initiation complex in the biosynthesis of polymyxin E.

Aminobutyrates↗