Biomedical subjects

N Iwata

Publications and source records attributed to N Iwata.

At least 19 recordsLinked to original sources

PubMed1998

Identification of a naturally occurring Pro15-Ser15 substitution in the serotonin5A receptor gene in alcoholics and healthy volunteers.

We screened the serotonin5A receptor gene coding region in 186 unrelated alcoholic patients and 187 controls. A relatively abundant amino acid substitution and two synonymous DNA substitutions were detected. Two synonymous variants, A12T and C789T, had rarer-allele frequencies of 23% and 1%, respectively. The Pro15Ser substitution is located in the amino terminal, extracellular domain of the receptor adjacent to a putative phosphorylation site. Pro15Ser had rarer-allele frequencies of 8.1% and 5.9% in Finnish alcoholic patients and controls, respectively (p=n.s.).

Alcoholism↗

PubMed1998

Characterization of temperature rise of the brain and the rectum following intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and kainate in rats.

Intracerebroventricular administration of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) or kainate caused a rise of the temperature of the brain and the rectum in urethane-anesthetized rats. An AMPA-kainate receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione (DNQX), significantly suppressed the AMPA- and kainate-induced rises of brain and rectal temperatures. An N-methyl-d-aspartate receptor antagonist, MK-801, also suppressed the rises of the brain and rectal temperatures induced by AMPA or kainate, but the profiles of the suppressive effects of MK-801 were different between rats treated with AMPA and kainate. An antipyretic agent, indomethacin, completely suppressed the AMPA-induced rises of brain and rectal temperatures. Although indomethacin completely suppressed the kainate-induced rise of the rectal temperature as well, the brain temperature was still raised. These findings suggest that distinct mechanisms may be involved in the temperature rise of the brain and the rectum mediated through AMPA and kainate receptor stimulation.

Analgesics, Non-Narcotic↗

PubMed1998

Molecular chaperone GRP94 binds to the Fanconi anemia group C protein and regulates its intracellular expression.

The FAC protein encoded by the gene defective in Fanconi anemia (FA) complementation group C binds to at least three ubiquitous cytoplasmic proteins in vitro. We used here the complete coding sequence of FAC in a yeast two-hybrid screen to identify interacting proteins. The molecular chaperone GRP94 was isolated twice from a B-lymphocyte cDNA library. Binding was confirmed by coimmunoprecipitation of FAC and GRP94 from cytosolic, but not nuclear, lysates of transfected COS-1 cells, as well as from mouse liver cytoplasmic extracts. Deletion mutants of FAC showed that residues 103-308 were required for interaction with GRP94, and a natural splicing mutation within the IVS-4 of FAC that removes residues 111-148 failed to bind GRP94. Ribozyme-mediated inactivation of GRP94 in the rat NRK cell line led to significantly reduced levels of immunoreactive FAC and concomitant hypersensitivity to mitomycin C, similar to the cellular phenotype of FA. Our results demonstrate that GRP94 interacts with FAC both in vitro and in vivo and regulates its intracellular level in a cell culture model. In addition, the pathogenicity of the IVS-4 splicing mutation in the FAC gene may be mediated in part by its inability to bind to GRP94.

Animals↗

PubMed1998

Expression of Xa1, a bacterial blight-resistance gene in rice, is induced by bacterial inoculation.

The Xa1 gene in rice confers resistance to Japanese race 1 of Xanthomonas oryzae pv. oryzae, the causal pathogen of bacterial blight (BB). We isolated the Xa1 gene by a map-based cloning strategy. The deduced amino acid sequence of the Xa1 gene product contains nucleotide binding sites (NBS) and a new type of leucine-rich repeats (LRR); thus, Xa1 is a member of the NBS-LRR class of plant disease-resistance genes, but quite different from Xa21, another BB-resistance gene isolated from rice. Interestingly, Xa1 gene expression was induced on inoculation with a bacterial pathogen and wound, unlike other isolated resistance genes in plants, which show constitutive expression. The induced expression may be involved in enhancement of resistance against the pathogen.

Amino Acid Sequence↗

PubMed1998

Can positive affect items be used to assess depressive disorders in the Japanese population?

BACKGROUND: The purpose of the present study was to examine the measurement properties of positive affect items among the Japanese population. METHODS: Responses to the Japanese version of the Center for Epidemiologic Studies Depression Scale and four additional negatively revised items of the original positive affect items were compared for 85 Japanese psychiatric out-patients with dysphoric-mood-related symptoms and 255 demographically matched controls. RESULTS: Responses to positive affect items were generally comparable between the two groups, whereas responses to negative symptom items were markedly different (P < 0.002 for all comparisons). The group difference was most marked for symptom persistence. Responses to the four negatively revised items of positive affect revealed a similar picture to that of the negative symptom items. The internal consistency of the scale significantly improved when the original positive affect items were replaced by the negatively revised items (P < 0.001 for both). CONCLUSIONS: Positive affect items with positive wording cannot be used to assess depressive disorders in the Japanese population adequately, but this can be done with the corresponding negatively revised items.

Adult↗

PubMed1998

Antimicrobial activity of a compound isolated from an oil-macerated garlic extract.

A compound showing antimicrobial activity was isolated from an oil-macerated garlic extract by silica gel column chromatography and preparative TLC. On basis of the results of NMR and MS analyses, it was identified as Z-4,5,9-trithiadeca-1,6-diene-9-oxide (Z-10-devinylajoene; Z-10-DA). Z-10-DA exhibited a broad spectrum of antimicrobial activity against such microorganisms as gram-positive and gram-negative bacteria and yeasts. The antimicrobial activity of Z-10-DA was comparable to that of Z-ajoene, but was superior to that of E-ajoene. Z-10-DA and Z-ajoene are different in respect of substitution of the allyl group by the methyl group flanking a sulfinyl group. This result suggests that substitution by the methyl group would also be effective for the inhibition of microbial growth.

Anti-Bacterial Agents↗

PubMed1998

A convenient and efficient synthesis of sialyl Lewis X.

A convenient synthesis of the sialyl Lewis X (sLe(x)) tetrasaccharide, NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc (8), as a carbohydrate ligand for selectins is described. The key step is the reaction between NeuAc alpha 2-3GalSMe (5) as a glycosyl donor and the suitably protected Fuc alpha 1-3GlcNAc derivative (4) as the glycosyl acceptor by using dimethyl(methylthio)sulfonium triflate (DMTST) as the promoter.

Carbohydrate Sequence↗

PubMed1998

Development of an enzyme-linked immunosorbent assay using recombinant chicken anemia virus proteins expressed in a baculovirus vector system.

Recombinant baculoviruses were constructed to express the putative proteins VP1, VP2 or VP3 of the chicken anemia virus (CAV). The recombinant VP1, VP2 or VP3 were detected by SDS-PAGE, and their molecular weights were 50, 30/27 and 16 kDa, respectively. The VP2 and VP3 reacted with sera from CAV-infected chickens in Western blot analysis and when used as an enzyme-linked immunosorbent assay (ELISA) antigen, but VP1 did not. Antibodies to CAV were detected, by ELISA using crude insect cell lysates containing VP2 or VP3, from 2 to 20 weeks or 2 to 7 weeks after CAV infection, respectively. These findings indicate that recombinant VP2 and VP3 expressed in the baculovirus vector system can be used as antigens to detect anti-CAV antibodies in ELISA.

Animals↗

PubMed1998

Prevalence of chronic fatigue syndrome in a community population in Japan.

In order to know the prevalence of chronic fatigue syndrome (CFS) in a community population in Japan, we analyzed data from a population-based interview survey. Two cases out of 137 respondents experienced chronic fatigue during a period of nine months, suffered from 50% or more reduction of daily activity due to fatigue and had no other physical or psychiatric diagnosis. Both of the two cases fulfilled the 1994 Centers for Disease Control (CDC) criteria and the British criteria. The point and nine-month prevalence rates of CFS were both 1.5% (95% confidence intervals, 0.4-5.2%). None fulfilled the 1989 CDC criteria for CFS. The prevalence rate of CFS was higher than those in previous studies in the Western countries, suggesting a need for future research on cross-cultural differences in the definition, prevalence and symptomatology of CFS.

Adolescent↗

PubMed1998

Positive and negative affect in the factor structure of the State-Trait Anxiety Inventory for Japanese workers.

The factor structure of Form Y of the State-Trait Anxiety Inventory (STAI-Y) was examined with 1,862 Japanese adult workers (1,509 men, 353 women). The initial principal component analysis extracted three factors based on the scree test. All 20 state (S-Anxiety) and 20 trait (T-Anxiety) items had dominant salient loadings on the first factor, which reflected "over-all anxiety." The three factors identified by an oblique (promax) rotation were labeled "anxiety-absent," "state anxiety-present," and "trait anxiety-present." All 20 items with dominant salient loadings on the first oblique factor were clearly grouped on the basis of their content, indicating the absence of anxiety. The second and third oblique factors, defined almost entirely by the STAI-Y anxiety-present items, clearly reflected the state-trait distinction in this sample of Japanese workers.

Adult↗

PubMed1998

The Japanese adaptation of the STAI Form Y in Japanese working adults--the presence or absence of anxiety.

Symptom endorsements and response patterns of 1,862 Japanese adult workers (1,509 males and 353 females) to the Japanese adaptation of the State-Trait Anxiety Inventory Form Y (STAI-JY) items, were examined in this study. The mean STAI-JY State and Trait anxiety scores of Japanese workers were substantially higher than those of American workers reported in the Manual, due primarily to the much higher scores of Japanese workers in responding to the anxiety-absent items. The correlations between the State and Trait anxiety-present scales and those of their anxiety-absent scales' counterparts were higher than those between the State anxiety-present and -absent scales and those of their Trait scales' counterparts. These findings suggested that responses to anxiety-present and -absent items should be considered independently in scoring the STAI-JY scales in Japanese working adults.

Adolescent↗

PubMed1997

Expression of a kinase-defective Eph-like receptor in the normal human brain.

We have identified a human Eph-family protein, HEP, gene located in human chromosomal region 7q33-->q35. The deduced amino acid sequence shared primary structural properties of Eph-family receptor tyrosine kinases. However, six invariant amino acids such as a lysine in the ATP-binding site and an aspartic acid in the phosphotransfer site of a conserved catalytic domain were substituted with other amino acid residues in HEP. Thus, no intrinsic tyrosine kinase activity was detectable in the catalytic domain expressed in CHO-K1 cell transfectants. Although most kinase-defective mutants of growth factor receptors have been reported as pathogenic receptors, its transcript was abundantly expressed in normal human adult tissues. A 135-kDa HEP protein was expressed in the human brain as much as in CHO-K1 cells transfected with a HEP cDNA expression vector. HEP is the first description of a kinase-defective Eph-family protein expressed abundantly in normal human tissues.

Adenosine Triphosphate↗

PubMed1997

Inhibition of NMDA-induced increase in brain temperature by N-omega-nitro-L-arginine and indomethacin in rats.

Intracerebroventricular administration of N-methyl-D-aspartate (NMDA) caused an increase in brain temperature, which appeared rapidly and preceded that in rectal temperature, in urethane-anesthetized rats. The increase in brain temperature was divided into two phases, an early increase and a late increase. Intracerebroventricular indomethacin, a cyclooxygenase inhibitor, completely abolished the NMDA-induced late increase, but not the early increase, in brain temperature. On the other hand, intracerebroventricular N-omega-nitro-L-arginine, a potent inhibitor of nitric oxide synthase, strongly suppressed both the early and the late increases. These findings suggest that both nitric oxide and prostaglandins may be involved in the increase in brain temperature after NMDA receptor activation.

Animals↗

PubMed1997

Effect of serum cholesterol levels on meta-chlorophenylpiperazine-evoked neuroendocrine responses in healthy subjects.

This study was undertaken to test the hypothesis that serum cholesterol levels might be associated with serotonergic receptor function. The participants were 10 healthy male subjects. After an overnight fast, the subjects received meta-chlorophenylpiperazine (m-CPP) or identical placebo capsules orally in a randomized, double-blind, cross-over design. Blood was obtained for measurement of prolactin, cortisol, adrenocorticotropic hormone (ACTH), and cholesterol. There were some significantly positive correlations between serum cholesterol levels and hormonal responses to m-CPP administration. These results suggest that serum cholesterol levels may be positively associated with serotonergic receptor function.

Adrenocorticotropic Hormone↗

PubMed1997

Small bowel transit time and colonic fermentation in young and elderly women.

Small bowel transit time (SBTT) in 15 young and 13 elderly women was assessed by measuring breath hydrogen concentrations after they had consumed a solid test meal. The meal consisted of 200 g cooked rice, 50 ml miso (made from fermented soy bean curd) soup, a boiled egg, and 95.5 g of cooked soy beans with mixed vegetables. This meal provided 17 g protein, 14.1 g fat, 92.9 g carbohydrate, 7 g dietary fiber, and 565 kcal total energy. The SBTT, calculated by a mean 3 ppm increase in breath hydrogen, was 191 +/- 14.9 (mean +/- SE) min in the young and 188.1 +/- 16.8 min in the elderly group; the difference was not significant. Breath hydrogen levels, however, were higher in the young than in the elderly group (39.1 +/- 6.3 ppm, vs 22.2 +/- 4.3 ppm, P < 0.05). There was an initial peak of hydrogen concentration, reached almost immediately after the ingestion of the meal, and then a decline to baseline within 60 min. This initial peak was not as pronounced in the elderly subjects. A second peak, indicating the entry of the test meal into the cecum, was more pronounced in the young than in the elderly group. SBTT did not differ significantly between the two groups, but colonic fermentation was more pronounced in the young, both in the fasting and the postprandial state.

Adult↗

PubMed1997

Distinct effects of MK-801 and (+/-)-2-amino-5-phosphonopentanoic acid on N-methyl-D-aspartate-induced rise of brain temperature in rats.

Intracerebroventricular (i.c.v.) administration of N-methyl-D-aspartate (NMDA) caused a biphasic rise of brain temperature, namely, a rapid, early rise and a larger, late rise, in urethane-anesthetized rats. I.c.v. pretreatment with a noncompetitive NMDA receptor antagonist, MK-801, attenuated the late rise of the brain temperature, but had no effect on the early rise, whereas i.c.v. pretreatment with a competitive NMDA receptor antagonist, (+/-)-2-amino-5-phosphonopentanoic acid (AP-5), attenuated both rises. AP-5 per se caused a rise in brain temperature without any rise of rectal temperature, whereas MK-801 per se caused no significant change of the brain or rectal temperature. This rise by AP-5 was suppressed by MK-801, suggesting an agonistic effect of AP-5 on NMDA receptors in rat brain in vivo.

2-Amino-5-phosphonovalerate↗

PubMed1997

Picolinic acid and indole-2-carboxylic acid: two types of glycinergic compounds modulate motor function differentially.

1. A putative agonist for the strychnine-sensitive glycine receptor picolinic acid was tested for its anticonvulsant activities in mice and muscle-relaxant activities in rats and compared with indole-2-carboxylic acid (I2CA), an antagonist for the strychnine-insensitive glycine receptor. Their effects on segmental reflexes in the cat spinal cord were examined to elucidate their sites of action. 2. Picolinic acid (200 and 400 mg/kg IP) delayed the onsets of strychnine- but not pentylenetetrazole-induced seizures. It delayed the onsets of bicuculline-induced seizures only at the higher dose. I2CA (200 and 400 mg/kg IP) delayed the onsets of these 3 kinds of seizures. Both compounds reduced muscle tone in rat decerebrate rigidity at a dose of 100 mg/kg IV. 3. Picolinate methylester, a picolinate derivative with higher lipophilicity, depressed spinal reflexes in both intact and spinalized cats at cumulative doses of 25 to 200 mg/kg IV. I2CA (50 mg/kg IV) inhibited spinal reflexes only in intact preparations. 4. These results suggest that the anticonvulsant and muscle-relaxant activities of picolinic acid (PA) are due to inhibition of spinal neurons, but that I2CA selectively affects supraspinal structures.

Animals↗

PubMed1997

Pharmacology of the new reversible inhibitor of monoamine oxidase A, RS-8359.

RS-8359 is a new reversible inhibitor of monoamine oxidase A (RIMA). With a selectivity ratio of about 2200 for the A:B enzyme types, it is one of the most specific of this class of compounds. As a result, it shows relatively little effect upon blood pressure when administered together with tyramine, thus effectively eliminating the 'cheese' effect which has contributed to the limited clinical use of the classical monoamine oxidase inhibitors (MAOIs). RS-8359 shows little affinity for the common central nervous system receptors and little anticholinergic effect. These characteristics suggest a relatively benign adverse event profile, which may be particularly advantageous in the elderly and may generally contribute to patient acceptance and compliance. In terms of its effects upon serotonin (5-hydroxytryptamine), RS-8359 gives increases similar to those of other MAOIs with activity sustained for about 9 h. In behavioural investigations, the compound gives results similar to those found with several antidepressants widely used in the clinic. Overall, the pharmacology of RS-8359 indicates that it should have antidepressant activity in man.

Animals↗