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Biomedical subjects

N Iwata

Publications and source records attributed to N Iwata.

At least 163 records · Page 9Linked to original sources
PubMed1991

An immunohistochemical study of MAP2 and clathrin in gerbil hippocampus after cerebral ischemia.

Changes in MAP2 and clathrin immunoreactivity were studied in gerbil hippocampus after transient cerebral ischemia. MAP2 immunoreactivity decreased significantly by 1 h in the subiculum-CA1 and CA2 areas which correspond to reactive change, while no decrease was observed in CA1 until day 4. Before the initiation of delayed neuronal death, MAP2 immunoreactivity was not changed in CA1. On the other hand clathrin immunoreactivity increased in the pyramidal cell layer of CA1 by 3 h after ischemia and remained high for 2 days. Clathrin immunoreactivity in the pyramidal cell layer of CA1 diminished after delayed neuronal death. The transient change of clathrin was noted especially in CA1 in the period prior to delayed neuronal death. These results imply an abnormal change in clathrin turnover after ischemia, which may participate in the pathogenesis of delayed neuronal death.

Animals↗
PubMed1991

Molecular cloning of a cDNA and a gene encoding an immunomodulatory protein, Ling Zhi-8, from a fungus, Ganoderma lucidum.

A large amount of the novel immunomodulatory protein Ling Zhi-8 (LZ-8) is synthesized in the mycelia of Ganoderma lucidum (Kino, K., Yamashita, A., Yamaoka, K., Watanabe, J., Tanaka, S., Ko, K., Shimizu, K., and Tsunoo, H. (1989) J. Biol. Chem. 264, 472-478). A cDNA and a gene for LZ-8 were isolated and characterized. The mixed oligonucleotide probes for LZ-8 cDNA were designed from the results of protein sequencing (Tanaka, S., Ko, K., Kino, K., Tsuchiya, K., Yamashita, A., Murasugi, A., Sakuma, S., and Tsunoo, H. (1989) J. Biol. Chem. 264, 16372-16377) and were used for screening the mycelial cDNA library. The nucleotide sequence of the cloned cDNA confirms the amino acid sequence of LZ-8 that was previously determined by protein sequencing. The clones containing the LZ-8 gene (lz-8) were obtained from the mycelial genomic DNA library using the cDNA probe. Two CCAAT-like sequences and one TATA box were found at the upstream region of the postulated transcription initiation site of lz-8. A small intron (61 nucleotides long) divided lz-8 into two exons at the 5'-untranslated region. The other characteristic sequences were also found around the postulated transcription initiation site and around the poly(A) additional site.

Adjuvants, Immunologic↗
PubMed1991

Interpersonal awareness and smoking behavior in the workplace.

A questionnaire survey was conducted in small-scale production companies in Japan to examine "interpersonal awareness" and smoking behavior in the workplace. Interpersonal awareness (IA) of smokers is defined as awareness of other people's presence when smoking. Study participants were 1048 smokers and 744 nonsmokers, contrasted by worksite: office or production. Controlling for selected baseline variables, office work smokers, who smoked more in the workplace than production work smokers (77.4% vs 51.6%, p < .001), had a higher IA in the workplace (75.5% vs 58.9%, p < .001) but did not differ in IA at home (69.7% vs 66.0%). In male smokers of both worksites, degree of IA in the workplace correlated positively with that at home (rs = .36, p < .001, office; rs = .45, p < .001, production), and daily cigarette consumption correlated negatively with degree of IA at home (rs = -.44, p < .001, office; rs = -.17, p < .001, production). A predilection for smoking more at home than in the workplace correlated with higher IA in the workplace for male office smokers (rs = -.21, p < .01). In contrast, a predilection for smoking more at home than in the workplace correlated with lower degree of IA at home for production smokers of both sexes (rs = 20, p < .001, male; rs = .53, p < .05, female). Interpersonal awareness is deemed an important behavioral factor for smoking workers.

Adult↗
PubMed1991

Deamination of norepinephrine, dopamine, and serotonin by type A monoamine oxidase in discrete regions of the rat brain and inhibition by RS-8359.

Levels of monoamines and their metabolites were determined in the cortex, hippocampus, and striatum of rats killed by microwave irradiation. Moclobemide (20 mg/kg, p.o.) and clorgyline (10 mg/kg, p.o.), type A monoamine oxidase (MAO-A) inhibitors, increased the levels of normetanephrine (NM) and 3-methoxytyramine (3MT) and decreased those of 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5HIAA) in almost all three regions. Deprenyl (10 mg/kg, p.o.), a type B monoamine oxidase inhibitor, however, little affected monoamine and metabolite levels in all regions. The maximum effects of RS-8359 (10 mg/kg, p.o.) were obtained at 2 to 6 hr after administration, when the levels of norepinephrine (NE), NM, 3MT, and serotonin (5HT) in all regions and dopamine (DA) in the striatum increased, while DOPAC and HVA levels decreased. The levels of monoamines and metabolites had returned to normal by 20 hr after administration. Dose-dependency of the effects of RS-8359 on monoamine metabolites was observed at doses up to 30 mg/kg (p.o.) at 1 and 6 hr after administration. In conclusion, NE, DA, and 5HT are exclusively or preferentially deaminated by MAO-A in the cortex, hippocampus, and striatum of rats, and RS-8359 exhibits a reversible MAO-A inhibitory action in all three regions tested in vivo.

Animals↗
PubMed1990

Carbonyl reductases from rat testis and vas deferens. Purification, properties and localization.

Three enzyme forms (T1, T2, T3) from rat testis and two from rat vas deferens (V1, V2) of carbonyl reductase have been highly purified to apparent homogeneity. These carbonyl reductases from rat reproductive organs have several similarities in terms of molecular mass (32-33 kDa), isoelectric point (pI 5.9-6.4), immunochemical properties, cofactor requirement (NADPH dependency) and sensitivity to sulfhydryl reagents. The isoenzymes from the vas deferens (V1, V2) have similar catalytic activities, whereas those from the testis (T1, T2, T3) showed different catalytic activities from each other. All enzymes, however, reduced quinones, aromatic aldehydes and ketones, while T3, V1 and V2 were characterized as possessing high affinity towards prostaglandins. An immunoinhibition study using a specific antibody indicated that these enzymes were solely responsible for the overall catalytic activities of 13, 14-dihydro-15-oxo-prostaglandin F2 alpha, 4-benzoylpyridine, and 4-nitroacetophenone reduction and prostaglandin F2 alpha oxidation in both testis and vas deferens cytosol. The immunohistochemical staining revealed a positive immunoreactivity to antibody only in the Leydig cells of the testis, but neither the germ cells nor Sertoli cells in the seminiferous tubule. The staining also showed that the enzymes in the vas deferens were primarily localized in mucosal epithelium cells.

Alcohol Oxidoreductases↗
PubMed1990

Is picolinic acid a glycine agonist at strychnine-sensitive receptors?

By means of unit recording and electrophoretic application, the effect of picolinic acid on feline spinal interneurons in situ was studied in comparison with glycine. Picolinic acid inhibited neuronal firing in 60% of neurons and in some cases the inhibitory actions were antagonized by strychnine. Inhibition of firing by glycine, which was also strychnine-sensitive, was reduced in case of concomitant administration of picolinic acid. These results suggest that picolinic acid might act as a glycine agonist at strychnine-sensitive receptors.

Animals↗
PubMed1990

The purification and properties of aldose reductase from rat ovary.

Aldose reductase has been highly purified from rat ovary to apparent homogeneity, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme proved to be a monomeric protein with a molecular weight of about 39,900. The enzyme catalyzed the NADPH-dependent reduction of a number of aromatic and aliphatic aldehydes as well as aldo-sugars. The enzyme was potently inhibited by p-chloro-mercuribenzoate and a commercially developed aldose reductase inhibitor, M79175. The result of an immunoinhibition study, using antibody against the purified enzyme, indicated that the enzyme was responsible for more than 50% of the overall catalytic activity of D-glucose reduction in rat ovarian cytosol. Western blotting analysis revealed that immunoreactive proteins to anti-ovarian aldose reductase antibody were present in adrenal gland, various reproductive tissues, brain, lung, and heart of rats. Furthermore, ovarian tissues of various species contained immunoreactive proteins, though in small amounts. The enzyme was primarily localized in the granulosa cells and oocytes of all stages of follicular development during the estrous cycle, though it was also found in the corpora lutea cells in the pregnant rats.

Aldehyde Reductase↗
PubMed1990

Inhibitory effect of glucocorticoid and stimulatory effect of human chorionic gonadotropin on ovarian carbonyl reductase in rats.

Effects of three glucocorticoids on ovulation, and on content and activity of ovarian carbonyl reductase in rats were investigated. Glucocorticoid treatment caused both significant decrease in ovarian and uterine weights, blockade of ovulation and marked decrease in content and activity of ovarian carbonyl reductase. Furthermore, the weak immunoreactivity to antibody against ovarian carbonyl reductase was shown in the theca cells and the interstitial gland cells in the glucocorticoid-treated ovary. The treatment with hCG (LH activity specific) restored the ovarian weight, and both the content and activity of ovarian carbonyl reductase, which were inhibited by glucocorticoids, to control level as well as ovulation. These results indicate that the ovarian carbonyl reductase may be closely involved in ovarian function, especially ovulation, and may be an LH-dependent enzyme, because it is well known that glucocorticoids inhibit both LH surge and ovulation in rats.

Alcohol Oxidoreductases↗
PubMed1990

Immunological and enzymological localization of carbonyl reductase in ovary and liver of various species.

The tissue distribution of carbonyl reductase in ovary and liver of various animal species was investigated by measuring the reduction of 13,14-dihydro-15-keto-prostaglandin F2a, a specific substrate for rat ovarian carbonyl reductases, and by means of Western blotting analysis using anti-rat ovarian carbonyl reductase antibody. The highest ovarian carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was found in rat among ten animal species tested, followed by hamster and monkey. The immunoreactive protein was detected in hamster and monkey ovaries. Although carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was not detectable in non-pregnant rabbit ovary, pregnant rabbit ovary showed not only moderate activity but also immunoreactivity with anti-rat ovarian carbonyl reductase antibody. On the other hand, carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a was detected in hepatic tissue of all the species tested, except for rat and left-eye flounder. Immunoreactive proteins were present in hepatic tissue of various species that exhibited measurable carbonyl reductase activity towards 13,14-dihydro-15-keto-PGF2a.

Alcohol Dehydrogenase↗
PubMed1990

Changes in rat ovarian carbonyl reductase activity and content during the estrous cycle, and localization.

Carbonyl reductase activity and content in the rat ovary were measured at various stages of the estrous cycle, and the enzyme protein in the ovary was localized by immunohistochemistry. The enzyme activity increased after the preovulatory surge of luteinizing hormone (LH) on proestrus, and the enzyme content began to increase prior to the LH surge. Although the enzyme content reached the highest level at 2000 h and remained at a plateau for 8 h, the enzyme activity increased linearly until it reached the highest level at 0800 h on the morning of estrus. At their maximum, enzyme activity and content were approximately 1.5-fold and 2-fold greater, respectively, then basal diestrus values. The enzyme protein amounted to 1-4% of the ovarian cytosolic protein. An immunohistochemical study revealed that the enzyme was primarily localized in interstitial gland cells and theca interna cells of secondary and Graafian follicles as well as atretic follicles.

Alcohol Oxidoreductases↗
PubMed1990

Changes and localization of ovarian carbonyl reductase during pseudopregnancy and pregnancy in rats.

The present study investigates changes in the activity and enzyme content of ovarian carbonyl reductase (CR), which catalyzes the reduction of 9-keto and 15-ketoprostaglandins in rats during pseudopregnancy and pregnancy. The activity of ovarian CR decreased from the onset of pseudopregnancy and pregnancy, reaching 20-30% of the Day 1 value by Day 12 of pseudopregnancy and 50-60% of the Day 1 value by Day 14 of pregnancy. In the case of pregnant rats, the enzyme activity maintained a minimal level between Day 14 of pregnancy and Day 22 of parturition. An acute increase of the enzyme activity was found on the morning after parturition. The CR content in the ovary maintained a constant level from Day 1 to Day 12 of pseudopregnancy and to Day 18 of pregnancy. In pregnant rats, there was a gradual decrease after 18 days and then a surge during parturition. CR was primarily localized in interstitial gland cells and in theca interna cells but was not found in corpora lutea cells in the ovary during the estrous cycle. Additional immunostaining was also observed in corpora lutea cells during pseudopregnancy and pregnancy. The changes in ovarian CR activity, i.e. the rapid decrease with progressing pseudopregnancy and pregnancy, correlated with the increase in progesterone and the decrease in LH. These results indicate that rat ovarian CR may be regulated via the hypothalamo-pituitary-ovarian axis and may also be involved in luteal function.

Alcohol Oxidoreductases↗
PubMed1990

S-adenosyl-L-methionine ameliorates reduced local cerebral glucose utilization following brain ischemia in the rat.

The average values of the local cerebral glucose utilization (LCGU) were approx. 35-110 mumols/100 g/min in various nuclei in the brain of sham-operated animals. The values, however, were decreased by 25-75% in all areas examined at 24 hr after 4-vessel occlusion (forebrain ischemia) for 0.5 hr. Particularly, the LCGU values in the forebrain nuclei such as the cerebral cortices and thalamus were severely reduced, while that in the nuclei in the midbrain and hindbrain such as the red nucleus, chochlear nucleus and vestibular nucleus were slightly reduced. In rats treated with S-adenosyl-L-methionine (SAM, 100 mg/kg, i.p.) every 1 hr for 6 times from the recirculation, however, the LCGU values were increased in all brain structures by 35-195% in the forebrain ischemic rat. A significant increase was observed in the cerebral neocortices, caudate-putamen, lateral septal nucleus, thalamic nuclei, substantia nigra, cerebellum and some other nuclei. In some forebrain structures whose LCGU were mildly reduced to approx. 60-70% by the ischemia, SAM recovered the LCGU to more than 90% of the value in the sham-operated group. Thus it was concluded that SAM ameliorated widely ischemia-induced reduction of LCGU in the rat.

Animals↗
PubMed1990

Participation of type A monoamine oxidase in the activated deamination of brain monoamines shortly after reperfusion in rats.

Changes in monoamine levels during and after ischemia and effects of RS-8359, a type A monoamine oxidase (MAO-A) inhibitor, were studied in the cerebral cortex, hippocampus, and striatum of rats killed by microwave irradiation. The patterns of the changes in norepinephrine (NE), dopamine (DA), and serotonin (5HT) levels were similar during ischemia: All these monoamines decreased in all three regions. After reperfusion, however, the three monoamines showed different patterns of changes: NE, except in the striatum, decreased further; DA increased over the controls; 5HT remained suppressed in all three regions. With regard to the metabolites of the monoamines, the changes during and after reperfusion were almost similar in all regions: O-methylated metabolites, normetanephrine and 3-methoxytyramine, markedly increased during ischemia; After reperfusion, the elevated levels of normetanephrine and 3-methoxytyramine returned to normal, while deaminated metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid, homovanillic acid (HVA), and 3-methoxy-4-hydroxy-phenylethyleneglycol clearly increased. RS-8359 pretreatment (30 mg/kg, p.o.) at an hour prior to ischemia elevated the levels of NE in the cortex and hippocampus during ischemia and inhibited the increases in DOPAC and HVA levels and the decrease in 3MT levels at 30 min after reperfusion. These results suggest that deamination of NE, DA, and 5HT is activated by the increases in the substrates for MAO in all three regions, except the noradrenergic system in the striatum, and that MAO-A participates in the activated deamination after reperfusion.

Animals↗
PubMed1990

[Analyses of neurotic symptoms and subjective symptoms of fatigue in seamen during a long voyage].

The variations of neurotic symptoms and subjective symptoms of fatigue were studied in relation to circumstances aboard ship in subsamples of the crew (N = 24) and students and researchers (N = 24) of a training ship belonging to a university during a summer voyage of the North Pacific route in 1987. The data were obtained by a self-administered questionnaire administered seven times before and during the voyage. The present study analysed the data collected during the 40 d voyage (the first four questionnaires including that before departure). Complaints of neurotic symptoms and fatigue were reported to be much greater in the present sample than those in a general occupational setting. Although the complaints reported by students and researchers decreased at landing, complaints of physical fatigue reported by the crew increased at landing but those of mental fatigue hardly changed. With regard to correlation between the values of the responses to circumstances aboard ship and the values of neurotic symptoms and fatigue, "quality of sleep" was significantly correlated with these symptoms for the crew. For the students and researchers, significant correlations were demonstrated between such items as "boredom toward work" and "quality of sleep", and physical fatigue, between the "anxiety over disease" and mental fatigue and "anxiety over disease", "risk of injury" and "fear of death" and neurotic symptoms in the first survey after departure (13th day).

Adult↗
PubMed1989

The purification and properties of NADPH-dependent carbonyl reductases from rat ovary.

Two carbonyl reductases have been highly purified from rat ovary to apparent homogeneity. Though they have similarities in terms of molecular weight (33,000), substrate specificities, inhibitor sensitivities, amino acid composition, and immunological properties, they differed in pI values (6.0 and 5.9). Both enzymes reduced aromatic aldehydes, ketones, and quinones at higher rates, compared to prostaglandins and 3-ketosteroids, whereas they showed higher affinity for prostaglandins and 3-ketosteroids. The enzymes also catalyzed oxidation of the 9-hydroxy group of prostaglandin F2 alpha. Moreover, they showed the remarkable characteristic of catalyzing the reduction of not only the 9-keto group of prostaglandin E2 but also the 15-keto group of 13,14-dihydro-15-keto-prostaglandin F2 alpha. Both enzymes were inhibited by SH-reagents, quercitrin, indomethacin, furosemide, and disulfiram. The results of immunoinhibition, using antibody against the purified enzymes, indicated that the enzymes were solely responsible for the overall catalytic activities of prostaglandin E series reduction, as well as 13,14-dihydro-15-keto-prostaglandin F2 alpha reduction and prostaglandin F2 alpha oxidation in rat ovarian cytosol. Western-blot analysis revealed that immunoreactive proteins were present in adrenal gland and various reproductive tissues except uterus of rats.

Alcohol Oxidoreductases↗
PubMed1989

Comparative studies of the effects of RS-8359 and safrazine on monoamine oxidase in-vitro and in-vivo in mouse brain.

The effect of RS-8359, pyrimidine on monoamine oxidase (MAO) has been compared with a hydrazinic MAO inhibitor, safrazine (beta-piperonylisopropylhydrazine hydrochloride,) which is a MAO inhibitor used clinically. In-vitro radiochemical determination of MAO activity showed that the IC50 of RS-8359 was 0.52 microM for the deamination of 5-hydroxytryptamine (5-HT) in the mouse brain mitochondrial preparation, while beta-phenylethylamine (PEA) deamination was inhibited by only 20% at 100 microM of the drug. 5-HT deamination in the brain homogenate prepared from mice killed 60 min after administration of RS-8359 was inhibited significantly by 14 and 48%, at 30 and 100 mg kg-1 (p.o.), respectively, while deamination of PEA was little affected at the same doses. On the other hand, safrazine strongly inhibited both 5-HT and PEA deaminations, but showed no selectivity toward the substrate used. The extent of MAO inhibition by RS-8359, measured fluorometrically with kynuramine as a substrate in the brain homogenate, was independent of preincubation up to 80 min. In contrast, the inhibitory potency of safrazine was strengthened by preincubation in a time-dependent manner. Oral administration of RS-8359 (3-30 mg kg-1) caused a dose-dependent increase in endogenous monoamines in mouse brain, which disappeared a few hours after its administration. Increase in monoamine content caused by safrazine lasted for at least 24 h. These results indicate that RS-8359 is a reversible and specific inhibitor of MAO-A, while safrazine is an irreversible and non-specific MAO inhibitor, in-vivo and in-vitro in mouse brain.

Animals↗