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S Ikemoto

Publications and source records attributed to S Ikemoto.

At least 19 recordsLinked to original sources
PubMed2001

Susceptibility to subsequent episodes of spontaneous recurrence of methamphetamine psychosis.

We examine susceptibility to subsequent spontaneous recurrences of methamphetamine psychosis (i.e. flashbacks) in 11 flashbackers with a single episode and in nine flashbackers with subsequent episodes. All had undergone frightening stressful experiences during previous MAP use. Mild psychosocial stressors then triggered flashbacks. During flashbacks, the nine flashbackers with subsequent episodes had more markedly increased norepinephrine levels, with slightly increased 3-methoxytyramine levels. The duration of imprisonment in this subgroup approached significantly long levels than in the 11 flashbackers with a single episode. Robust noradrenergic hyperactivity with slightly increased dopamine release may therefore predict subsequent flashbacks. Longer exposure to distressing situations may also contribute to robust noradrenergic hyperactivity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2001

A head-attachable device for injecting nanoliter volumes of drug solutions into brain sites of freely moving rats.

We describe a head-mounted micropump-injection system designed for the infusion of nanoliter volumes of drug solutions into discrete brain regions of the freely moving rats. Using a miniature step motor, the micropump-injection system can be readily constructed from commercially available supplies. In calibrating the micropump-injection system, we found that it will deliver a reliable volume of 50 nl per infusion over a 1-h period, with an infusion given every 1 min. From in vivo testing, we also found that rats readily self-administered up to 100 infusions of D-amphetamine into the nucleus accumbens at regular intervals, suggesting that this system can deliver constant volumes of infusions over time in freely moving rats. It (1) attaches easily to an implanted guide, (2) is compact and durable, (3) weighs only 10 g, and (4) is well tolerated with no apparent discomfort to the animal. This system overcomes some of the weaknesses of currently used intracranial self-administration systems.

Amphetamine↗
PubMed2001

Androgen regulation of CYP4B1 responsible for mutagenic activation of bladder carcinogens in the rat bladder: detection of CYP4B1 mRNA by competitive reverse transcription-polymerase chain reaction.

Significant sex differences exist among cases of bladder cancer in humans as well as in experimental animals such as rats. Aromatic amines such as benzidine and 2-naphthylamine are known to induce bladder cancer. These carcinogenic amines are activated to genotoxic substances by cytochrome P 450 CYP4B1, which is present in bladder mucosa. In this study, regulation of CYP4B1 was investigated to elucidate sex difference in bladder carcinogenesis. Competitive reverse transcription-polymerase chain reaction was used to investigate the expression of rat CYP4B1 mRNA occurring in small amounts of tissue such as bladder tissue. Expression of CYP4B1 in the bladder of male rats increased with development but not in that of female rats. Moreover, mature male rats exhibited higher expression of CYP4B1 in the bladder than did mature female rats. Castration of male rats decreased CYP4B1 levels and treatment with testosterone led to a partial recovery of CYP4B1 levels. These results indicate that CYP4B1 levels in the rat bladder are partly regulated by androgens. Furthermore, the present findings suggest that the sex difference observed in bladder carcinogenesis was due to sex-different expression of CYP4B1 in bladder tissue.

Age Factors↗
PubMed2001

Nucleus accumbens amphetamine microinjections unconditionally elicit 50-kHz ultrasonic vocalizations in rats.

The authors have hypothesized that, in adult rats, 50-kHz ultrasonic vocalizations (USVs) index a state characterized by high arousal and expectations of reward. This study was conducted to investigate whether dopamine agonism of the nucleus accumbens (NAcc) could evoke such an appetitive state, by examining the effects of NAcc amphetamine (AMPH) microinjections on USVs. Intra-NAcc AMPH injections (0.3, 1.0, 3.0, 10.0 microg unilaterally) produced robust, dose-dependent increases in 50-kHz USVs, which could not be accounted for by concomitant increases in locomotor activity (LA). However, AMPH injections into dorsal control caudate putamen sites produced a modest, dose-dependent increase in LA without significant increases in 50-kHz USVs. These findings indicate that NAcc AMPH microinjections selectively evoke 50-kHz USVs in rats, supporting the notion that dopamine elevations in the NAcc may unconditionally elicit a state of reward anticipation.

Amphetamine↗
PubMed2001

Are tobacco use and urine pH indicated as risk factors for bladder carcinoma?

BACKGROUND: Many case-control and cohort studies have shown a positive relationship between bladder carcinoma and tobacco use. Recently, urine pH has been reported to influence aromatic amine carcinogenesis, which have been implicated as potent carcinogens in bladder carcinoma patients. Herein the correlation between bladder carcinoma, tobacco use and urine pH is reported. METHOD: One hundred and forty-one patients with bladder carcinoma and 128 patients with benign prostatic hyperplasia or urolithiasis as controls were selected. All patients were admitted to Osaka City University Hospital for the purpose of surgical treatment. Urine pH was checked by a test tape. RESULTS: Of the patients with bladder carcinoma, 106 were smokers and 35 were non-smokers. In contrast, the number of smokers in the control group was 76 and that of non-smokers was 52. The odds ratio in the bladder carcinoma group calculated for the smoker patients was 2.07, showing a significant correlation between bladder carcinoma and tobacco use. Regarding urine pH, acidic urine was found in 126 patients in the bladder carcinoma group and in 116 patients in the control group. The odds ratio in the bladder carcinoma group for acidic urine was 0.87, showing no significant relationship between bladder carcinoma and urine pH. CONCLUSION: The study found a positive relationship between bladder carcinoma and tobacco use; however, it could not establish a clear relationship between bladder carcinoma and urine pH, even in the smoker group.

Aged↗
PubMed2001

Troglitazone prevents the rise in visceral adiposity and improves fatty liver associated with sulfonylurea therapy--a randomized controlled trial.

Monotherapy with sulfonylurea may result in the exhaustion of pancreatic beta-cell function, fat accumulation, and dyslipidemia. We examined the possibility of dose reduction by administering sulfonylurea together with troglitazone, and investigated changes in insulin secretion and fat deposition. Seventy-eight patients with type 2 diabetes adequately controlled with glibenclamide were randomly allocated to a troglitazone (400 mg/d)-added group (n = 40) or a control group without placebo (n = 38) and monitored for 24 weeks. The daily dose of glibenclamide was adjusted to maintain stable HbA(1c) levels. Fat accumulation to the liver and thigh muscle were measured in mean Hounsfield units determined on computed tomography (CT) scan. Visceral fat accumulation (V), subcutaneous fat accumulation (S), and the V/S ratio were also determined by CT scan. The daily dose of glibenclamide and serum fasting insulin level in the troglitazone-added group significantly decreased (from 4.05 +/- 2.50 mg/d to 1.84 +/- 1.65 mg/d and from 8.47 +/- 4.62 microU/mL to 6.49 +/- 3.28 microU/mL, respectively) during the observation period compared with the control group (P < .01 and P < .01, respectively). Serum triglyceride and homeostasis model insulin resistance index (HOMA-R) in the troglitazone-added group decreased significantly in comparison to the control group (P < .05 and P < .01, respectively). The mean Hounsfield units of liver significantly decreased in the control group compared with the troglitazone-added group (P < .05). Visceral fat area and the V/S ratio significantly increased in the control group compared with the troglitazone-added group (P < .01 and P < .01, respectively). Glibenclamide monotherapy resulted in fat accumulation accompanied by dyslipidemia. An alternate conclusion is that troglitazone reversed type 2 diabetes (not sulfonylurea)-associated fat accumulation. The addition of troglitazone decreased daily doses of glibenclamide, preserved fasting insulin secretion, improved fat accumulation in liver, and prevented dyslipidemia.

Adipose Tissue↗
PubMed2001

Angiotensin converting enzyme genetic polymorphism is not associated with hypertension in a cross-sectional sample of a Japanese population: the Shibata Study.

BACKGROUND: The studies on the association of deletion/ insertion (D/I) polymorphism of angiotensin converting enzyme (ACE) gene with blood pressure and hypertension reported contradictory results. Because there was no population-based study in Japan, we examine the hypothesized association in a cross-sectional sample of a Japanese cohort. METHODS AND RESULTS: The blood pressure of 464 men and 876 women aged 40-80 years was measured, and their DNA was analyzed for ACE D/I genotypes. The prevalence of the D allele was 38.7 and 39.2% in men and women, respectively (overall 39%). There was a tendency for higher covariate (age, body mass index, albuminuria, hematocrit, alcohol consumption, smoking, diabetes mellitus, ischemic heart disease and antihypertensive medication) adjusted mean levels of diastolic blood pressure for the DD genotype in men but not in women. However, this tendency disappeared after dichotomization of blood pressure into diagnostic categories (normotension and hypertension). Results did not differ when the subjects were divided into two age groups (< or = 59 and > or = 60 years). Covariate-adjusted odds ratios for hypertension for presence of the D allele were close to the null value of one. ACE genetic variation accounted for only 0.1 and 0.7% of the inter-individual variation in systolic and diastolic blood pressure in men. These estimates were 0.2 and 0.1%, respectively, in women. CONCLUSION: Although there is a tendency of higher diastolic blood pressure in men with DD genotypes, there is no convincing evidence that ACE genotypes are associated with hypertension in this Japanese population.

Adult↗
PubMed2001

Molecular cloning of a cDNA coding for feline liver xanthine dehydrogenase.

A cDNA coding for feline liver xanthine dehydrogenase (XDH, EC 1.1.204) was amplified by RT-PCR and cloned for determining the sequence. The clones contained an open reading frame of 4002 base pairs encoding 1333 amino acid residues. The calculated molecular weight and isoelectric point were approximately 146 kDa and 7.0. Comparison of the deduced amino acid sequences indicated remarkable high homology, i.e., the amino acid residues of feline XDH shared approximately 90%, 87%, 87% and 86% identity with those of human, bovine, rat and mouse, respectively. The anino acid sequences of two putative iron-sulfur centers, one NAD binding site and one molybdenum binding site were well conserved among mammalian animals.

Amino Acid Sequence↗
PubMed2001

Microsatellite polymorphism in intron 14 of the canine BRCA1 gene.

Microsatellite polymorphism due to differences in CT dinucleotide repeats was demonstrated in intron 14 of the canine BRCA1 gene. Genotype analysis of 103 unrelated dogs from 30 different breeds detected the presence of five alleles, including 10 of the expected 15 genotypes. Gene frequencies were biased and all alleles with the exception of one were below 0.1. This polymorphism, which occurs at the intron of canine BRCA1 should prove to be a useful marker for detecting the loss of heterozygosity (LOH). One of the more notable findings of the present study was the detection of homozygotes of rare alleles. This finding identified an accumulation of rare alleles in specific canine breeds and demonstrated the usefulness of this characteristic for the biological study of dog evolution.

Animals↗
PubMed2001

[Apolipoprotein D].

Explore the source record for details and available documents.

Alzheimer Disease↗
PubMed2000

Stress induced spontaneous recurrence of methamphetamine psychosis: the relation between stressful experiences and sensitivity to stress.

We examined increased sensitivity to stress in relation to spontaneous recurrences of methamphetamine (MAP) psychosis (i.e., flashbacks). Plasma monoamine metabolite levels were assayed in: 26 flashbackers, of whom 11 were on neuroleptics before and during the study, and the other 15 received neuroleptics in the course of the study; 18 non-flashbackers with a history of MAP psychosis; eight subjects with persistent MAP psychosis; and 23 MAP user and 11 non-user controls. The 26 flashbackers had experienced stressful events and/or MAP-induced fear-related psychotic symptoms during previous MAP use. Mild psychosocial stressors then triggered flashbacks. During flashbacks plasma norepinephrine levels increased markedly; among the flashbackers, those with a history of stressful events, whether or not they had experienced fear-related symptoms, showed a further increase in 3-methoxytyramine levels. Stressful experiences, together with MAP use, may therefore induce sensitization to stress associated with noradrenergic hyperactivity, involving increased dopamine release, and so triggering flashbacks.

Adult↗
PubMed2000

Intra-medial prefrontal cortex injections of scopolamine increase instrumental responses for cocaine: an intravenous self-administration study in rats.

The present experiments examined the effects of muscarinic cholinergic receptor blockade in the nucleus accumbens (NAC) and medial prefrontal cortex (MPC) on intravenous cocaine self-administration. Adult male Sprague-Dawley rats were implanted with chronic indwelling jugular catheters and guide cannulae stereotaxically aimed at the NAC or MPC. The rats were then given the opportunity to intravenously self-administer cocaine (0.8 mg/kg/infusion) during daily 2-h sessions. Intra-NAC microinjections of methyl-scopolamine (2, 4, 8, 16, and 32 microg/side) or vehicle did not affect either the number of lever presses made or infusions delivered. On the other hand, intra-MPC injections of scopolamine significantly increased responding, although there was only a trend for an increase in the number of cocaine infusions. The effects of intra-MPC injections of scopolamine (8 and 16 microg/side) on locomotor activity were also evaluated. Intra-MPC injections of scopolamine (16 microg/side) produced significant increases in locomotor activity. However, these same microinjections decreased locomotor activity when the animals also received cocaine (15 mg/kg, i.p.). These results suggest that cholinergic neurotransmission at muscarinic receptors in the MPC is involved in regulating cocaine-maintained responding.

Animals↗
PubMed2000

Antitumor effects of Scutellariae radix and its components baicalein, baicalin, and wogonin on bladder cancer cell lines.

OBJECTIVES: To investigate the antitumor effects of Scutellariae radix and its components baicalein, baicalin, and wogonin on human bladder cancer cell lines (KU-1 and EJ-1) and a murine bladder cancer cell line (MBT-2). METHODS: Bladder cancer cells were incubated with various concentrations of the agents. Antiproliferative activity against the bladder cancer cell lines was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diplenyl tetrazolium bromide assay. In an in vivo experiment, the mice were subcutaneously injected with MBT-2 cells, and Scutellariae radix was orally administered at a dose of 2 or 10 mg per mouse one time daily for 10 days from day 11 to day 20. RESULTS: All the drugs inhibited cell proliferation in a dose-dependent manner, but baicalin exhibited the greatest antiproliferative activity. The concentration of baicalin necessary to obtain 50% inhibition was 3.4 microg/mL for KU-1, 4.4 microg/mL for EJ-1, and 0.93 microg/mL for MBT-2. For KU-1 and MBT-2, the percentage of cell survival significantly decreased (P <0.05) at a baicalin concentration of 1 microg/mL. In an in vivo experiment, antitumor effects of Scutellariae radix on C3H/HeN mice implanted with MBT-2 were investigated. All the control mice showed a progressive increase in tumor volume, reaching 2.81 +/- 0.18 cm(3) on day 20 and 5.36 +/- 0.44 cm(3) on day 25. However, when Scutellariae radix was orally administered at a dose of 10 mg per mouse one time daily for 10 days from day 11 to day 20, the tumor volume was 1.99 +/- 0.19 cm(3) on day 20 and 3.86 +/- 0.26 cm(3) on day 25, a significant inhibition of tumor growth (P <0.05). Conclusions. These results suggest that Chinese herbal medicines may become an attractive and promising treatment for bladder cancer.

Animals↗
PubMed2000

Comparative study of transurethral laser prostatectomy versus transurethral electroresection for benign prostatic hyperplasia.

BACKGROUND: Transurethral resection of the prostate (TURP) is the gold standard treatment for benign prostatic hyperplasia (BPH). Recently, less invasive transurethral laser prostatectomy, such as visual laser ablation (VLAP) or interstitial laser coagulation (ILCP), have been developed. Herein, we investigated the efficacy of VLAP and ILCP compared to TURP. METHODS: A total of 80 patients with BPH were treated: 20 patients by VLAP, 30 patients by ILCP and 30 patients by TURP. All patients were followed up for 12 months after their operations. Treatment outcomes were evaluated by four different criteria: (i) the International Prostatic Symptom Score (I-PSS), (ii) the maximum flow rate (Qmax), (iii) postvoided residual urine volume before treatment and one, three, six and 12 months after treatment, and (iv) prostatic volume before operation and three and six months postoperatively. RESULTS: The I-PSS, Qmax and residual urine volume were significantly improved compared to baseline levels and the improvement continued for 12 months in the three groups: for I-PSS (P<0.001 in the VLAP group and P<0.0001 in the ILCP and TURP groups), Qmax (P<0.001 in the VLAP and ILCP groups, and P<0.0001 in the TURP group), residual urine volume (P<0.01 in the VLAP group and P<0.0001 in the ILCP and TURP groups). Significant reduction of the prostatic volume was recorded only in the ILCP and TURP groups (P<0.001). CONCLUSION: Visual laser ablation and ILCP can be good alternative treatments for BPH. Visual laser ablation provides good outcomes in patients with small-sized BPH and with risk factors such as heart disease or anticoagulation therapy.

Aged↗
PubMed2000

Increased sensitivity to stress in spontaneous recurrence of methamphetamine psychosis: noradrenergic hyperactivity with contribution from dopaminergic hyperactivity.

The significance of increased sensitivity to stress associated with noradrenergic hyperactivity involving dopaminergic change in spontaneous recurrences of methamphetamine (MAP) psychosis (flashbacks) was examined. Plasma monoamine metabolite levels were assayed in 18 subjects with flashbacks who had been exposed to stressful events plus MAP-induced frightening psychotic symptoms (N = 11) or frightening psychotic symptoms alone (N = 7) during previous MAP use, in 15 nonflashbackers with a history of MAP psychosis, in 8 subjects with persistent MAP psychosis, and in 27 control subjects. Monoaminergic values were subjected to a square-root transformation, rendering the distribution normal. The numbers of stressful events (mostly threatening events) and frightening psychotic symptoms were significantly higher in the flashbackers than in the nonflashbackers. Factors triggering flashbacks were mild psychosocial stressors (mostly a mild fear of other people). During flashbacks, plasma norepinephrine levels increased, and the flashbackers, 11 of whom had experienced stressful events plus frightening psychotic symptoms, had an additional small increase in plasma levels of 3-methoxytyramine, which is indicative of dopamine release. Thus, threatening stressful events, together with MAP use, may induce noradrenergic hyperreactivity to subsequent mild stressors. Threatening, stressful events plus frightening psychotic symptoms may further induce increased dopamine release in response to mild stressors. Increased sensitivity to stress associated with noradrenergic hyperactivity involving increased dopamine release may have elicited memories of MAP psychosis related to frightening, stressful experiences. The increased sensitivity may be critical for the development of flashbacks.

Adult↗
PubMed2000

Studies of amphetamine or methamphetamine psychosis in Japan: relation of methamphetamine psychosis to schizophrenia.

There exist clinical characteristics of methamphetamine (MAP) psychosis in the Japanese population. MAP psychosis involves paranoid-hallucinatory states indistinguishable from paranoid schizophrenia, with residual volitional disturbances (e.g., loss of spontaneity and idleness). Paranoid-hallucinatory states persist after the pharmacological effects of MAP have worn off and readily reappear upon a reinjection of MAP. Individuals with a history of MAP psychosis further undergo spontaneous recurrence of their paranoid-hallucinatory states in response to stress. The development of MAP psychosis might therefore be related to persisting brain damage or changes in brain metabolism induced by repeated MAP use, and thus studies of the clinical course and neurological basis of MAP psychosis could provide insights into the pathophysiology of schizophrenia. Accordingly, psychiatrists have studied the clinical characteristics of MAP psychosis and examined the neurobiological basis of MAP-induced behavioral sensitization, using animals. MAP-induced behavioral sensitization might well be related to dopamine supersensitivity; however, the contribution of presynaptic autoreceptors remains controversial, and other hypotheses should be considered. Recently, the process that triggers spontaneous recurrence of MAP psychosis (flashbacks) and corresponding peripheral neurotransmitter functions has been studied. Stress sensitization associated with noradrenergic hyperactivity, involving increased dopamine release, appears to be crucial in the development of flashbacks. Overall, MAP-induced susceptibility to paranoid-hallucinatory states and to abnormal behavior (e.g., stereotyped behavior) in animals is examined as a model for predicting relapses of paranoid schizophrenia. Further extensive studies on the neurobiological and molecular mechanisms of this susceptibility are required.

Amphetamines↗
PubMed2000

Susceptibility to subsequent episodes in spontaneous recurrence of methamphetamine psychosis.

The relation is examined between increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic changes, and susceptibility to subsequent spontaneous recurrences of methamphetamine (MAP) psychosis (i.e., flashbacks). Plasma monoamine metabolite levels were assayed in 23 flashbackers, 19 nonflashbackers with a history of MAP psychosis, 10 subjects with persistent MAP psychosis, and 21 MAP user and 9 nonuser controls. All 23 flashbackers had undergone frightening stressful experiences during previous MAP use. Mild psychosocial stressors then triggered flashbacks. The 12 flashbackers with further episodes had markedly increased norepinephrine levels and slightly increased plasma levels of 3-methoxytyramine, an index of dopamine release. While the 11 flashbackers with a single episode displayed small increases in norepinephrine and 3-methoxytyramine levels. Thus, robust noradrenergic hyperreactivity, involving increased dopamine release in response to mild stress may predispose to further episodes of flashbacks.

Analysis of Variance↗