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Takafumi Hori

Publications and source records attributed to Takafumi Hori.

11 recordsLinked to original sources
PubMed2006

High-dose of multiple antipsychotics and cognitive function in schizophrenia: the effect of dose-reduction.

We evaluated the effect of antipsychotic dose-reduction on the neurocognitive function of 17 schizophrenic patients (11 male and 6 female, mean age=42.4+/-11.3) who have been taking high-doses of multiple conventional antipsychotics. The mean (+/-SD) of total daily antipsychotic doses (in mg/day, chlorpromazine-equivalent) was 2,253 (+/-668) at baseline, which was reduced to 1,315 (+/-276). Possible changes in neurocognitive function were assessed using Wisconsin card sorting test (WCST) and continuous performance test (CPT). As controls, we examined WCST and CPT in 6 schizophrenic patients (4 male and 2 female, mean age=47.7+/-14.2) who had been taking high-doses of multiple antipsychotics (mean daily antipsychotic dose=1,753+/-165 mg) and declined to change their antipsychotic regimen. In WCST, the mean number of total correct answers significantly increased (53.2+/-16.3 vs. 63.8+/-19.6, P=0.035, Wilcoxon signed rank test); perseverative errors significantly decreased (54.4+/-27.3 vs. 35.4+/-20.1, P=0.013, Wilcoxon signed rank test) after the antipsychotic dose-reduction. In contrast, the control group showed no significant difference between the two WCST performances conducted with a three-month interval. The improvements in WCST performance significantly correlated with the decreases in PANSS negative syndrome score in the subject patients. No significant change was observed in CPT performances in either group. Our preliminary data shows that, in schizophrenic patients taking high-doses of multiple conventional antipsychotics, dose-reduction might lead to improvements in cognitive functions.

Adult↗
PubMed2006

Hypersalivation induced by olanzapine with fluvoxamine.

Hypersalivation has been reported as a side effect of atypical antipsychotics such as clozapine and olanzapine. As it is very common for antipsychotics to cause dry mouth due to anticholinergic effects, hypersalivation seems to be paradoxical. We present the case of a 34-year-old Japanese man with delusional disorder, somatic type (DSM-IV). He had chronic neck pain as well as somatic hallucination with hypochondriacal delusion for 4 years. Since combination therapy with atypical antipsychotics and selective serotonin reuptake inhibitors (SSRIs) has been introduced in the treatment of refractory psychiatric disorders such as schizophrenia, olanzapine (10 mg/day) was added to fluvoxamine treatment (200 mg/day) in this case. Subsequently, hypersalivation was induced without any extrapyramidal symptoms. It is suggested that hypersalivation was an adverse effect of olanzapine. Possible interaction olanzapine with fluvoxamine might increase the risk of the adverse effect. When combination therapy of atypical antipsychotics and SSRI is introduced, it should be used cautiously with careful observation. Underlying pharmacological and clinical problems will be discussed.

Adult↗
PubMed2006

[A case of Brugada syndrome with convulsive seizure during antidepressant administration: relation of antidepressant agents and arrhythmia leading to sudden death].

Brugada syndrome is an arrhythmogenetic disease characterized by electrocardiographic ST segment elevation in right precordial leads, which is called "coved type", and an increased risk of sudden death as the result of ventricular fibrillation. We presented a case of Brugada syndrome with a convulsive seizure, during administration of a tricyclic antidepressant for the treatment of a depressive state. A 43-year-old man with bipolar II disorder and obsessive-compulsive disorder was admitted to our hospital for the treatment of a depressive state. There was no medical history of heart failure. Nortriptyline was effective for his depressive as well as for obsessive symptoms. During the treatment, however, he presented a convulsive syncope. Electrocardiography (ECG) showed "coved type" ST segment elevation, and the patient consulted a cardiologist. Electrophysiological study revealed Brugada syndrome, and an implantable cardioverter defibrillator was placed. An overdose of antidepressants has been reported to produce a Brugada-type ECG because of its Na channel antagonism. However, in the present case, the abnormal ECG findings occurred following a usual dosage of nortriptyline. Thus, it is suggested that Brugada syndrome is related to a susceptibility to antidepressants in the present case. Every psychiatrist managing antidepressant therapy should be aware of Brugada syndrome and this ECG pattern, which may be a marker of sudden death.

Adult↗
PubMed2005

Genomewide high-density SNP linkage analysis of 236 Japanese families supports the existence of schizophrenia susceptibility loci on chromosomes 1p, 14q, and 20p.

The Japanese Schizophrenia Sib-Pair Linkage Group (JSSLG) is a multisite collaborative study group that was organized to create a national resource for affected sib pair (ASP) studies of schizophrenia in Japan. We used a high-density single-nucleotide-polymorphism (SNP) genotyping assay, the Illumina BeadArray linkage mapping panel (version 4) comprising 5,861 SNPs, to perform a genomewide linkage analysis of JSSLG samples comprising 236 Japanese families with 268 nonindependent ASPs with schizophrenia. All subjects were Japanese. Among these families, 122 families comprised the same subjects analyzed with short tandem repeat markers. All the probands and their siblings, with the exception of seven siblings with schizoaffective disorder, had schizophrenia. After excluding SNPs with high linkage disequilibrium, we found significant evidence of linkage of schizophrenia to chromosome 1p21.2-1p13.2 (LOD=3.39) and suggestive evidence of linkage to 14q11.2 (LOD=2.87), 14q11.2-q13.2 (LOD=2.33), and 20p12.1-p11.2 (LOD=2.33). Although linkage to these regions has received little attention, these regions are included in or partially overlap the 10 regions reported by Lewis et al. that passed the two aggregate criteria of a meta-analysis. Results of the present study--which, to our knowledge, is the first genomewide analysis of schizophrenia in ASPs of a single Asian ethnicity that is comparable to the analyses done of ASPs of European descent--indicate the existence of schizophrenia susceptibility loci that are common to different ethnic groups but that likely have different ethnicity-specific effects.

Chromosomes, Human, Pair 1↗
PubMed2005

Decreased cell proliferation in the dentate gyrus of rats after repeated administration of cocaine.

Cell proliferation in the dentate gyrus of hippocampus was assessed using in vivo labeling with 5-bromo-2'-deoxyuridine (BrdU) in adult rats that were administered cocaine (20 mg/kg) for 14 consecutive days. Rats showed increased stereotypy at a challenge dose of cocaine after 1 week of withdrawal, suggesting the acquisition of behavioral sensitization. Twenty-four hours after final injection of repetitive cocaine administration, a 26% decrease in BrdU-positive cells was observed, compared with control rats. However, this returned to control level within 1 week. No differences were observed in rats that received a single injection of cocaine. Differentiation of newly formed cells was not influenced. These data imply that the regulation of hippocampal cell proliferation by cocaine may be involved in the development of certain symptoms of addiction, such as cognitive impairment and acquisition of behavioral sensitization.

Animals↗
PubMed2004

Effects of single and repeated phencyclidine administration on [3H]flunitrazepam binding in rat brain.

Repeated administration of phencyclidine (PCP) induces behavioral sensitization to dopaminergic neural transmission. This phenomenon has been implicated in the pathophysiology of schizophrenia. Recently, GABAergic agonists have been shown to reduce behavioral activity induced by enhanced dopaminergic neural transmission, which is mediated by the GABA(A)/benzodiazepine (BZD) receptor complex. Thus, to investigate the role of BZD receptors during induction and expression of behavioral sensitization in PCP-sensitized animals, the effects of both single and repeated PCP administration on BZD receptors in rat brain were examined using in vitro quantitative autoradiography. Repeated PCP administration failed to significantly alter levels of [3H]flunitrazepam (FNZ) binding in any of the regions examined. However, significant increases in levels of [3H]FNZ binding were found in the nucleus accumbens and ventral pallidum 1 h after single administration of PCP. These results suggest that BZD binding sites may not play important roles in the development of PCP-induced sensitization at several sites of GABA(A)/BZD receptor complex, while changes in GABA function in the nucleus accumbens differ from other areas following single administration of N-methyl-D-aspartate (NMDA) antagonist.

Animals↗
PubMed2004

[A psychopathological study on three-dimensional computer graphics (3DCGs): special reference to pictures made by a schizophrenic patient before and after the onset].

A patient with catatonic type schizophrenia drawing 3-dimensional computer graphics (3DCGs) before and after the onset is reported. His 3DCGs are discussed from the view of psychopathology. A 21-year-old male was admitted to our hospital. He was an art student. For three months before admission, he had been absorbed in drawing 3DCGs. When he was asked to draw handmade pictures by his teacher, he experienced a bizarre mood and took an overdose of aspirin. At the time of admission, he was in a stupor state, and was diagnosed with catatonic type schizophrenia. After admission, he exhibited excitement and disorganized speech. These symptoms disappeared after administration of neuroleptics, and he was discharged. The 3DCGs he drew before and after the onset revealed several special characteristics. First, the compositions of his pictures were too geometric and too precise. Secondly, the themes of his pictures changed from romantic before the onset to symbolic after it, and the styles changed from realistic to abstractive after the onset. Finally, histograms of the 3DCGs revealed many colors before onset, which converged to simple colors after. Therefore, it was suggested that the latent pathological process at the beginning of schizophrenia might be reflected in his 3DCGs. 3DCGs are a new type of fine art. They can express beautiful and cool images more simply than handmade pictures. Due to these features, artists can create images of their innerworld, with less effort and talent than picture drawings, by computer assistance. This case suggests that the geometric working space, change-free viewpoints, and computer assistance, which are characteristics of the methods in making 3DCGs may be suitable for schizophrenic artists to create images of their innerworld. However, being absorbed in making 3DCGs could also promote the latent schizophrenic process to the onset.

Adult↗
PubMed2002

Repeated cocaine administration differentially affects NMDA receptor subunit (NR1, NR2A-C) mRNAs in rat brain.

We investigated the effects of intermittent intraperitoneal (i.p.) injections of cocaine (20 mg/kg) on subunit mRNAs of N-methyl-D-aspartate (NMDA) receptors (NR1/NR2A-2C) in the rat brain by in situ hybridization using phosphor screen analysis. The level of NR1 subunit mRNA significantly increased in hippocampal complexes 1 h after a single i.p. injection of cocaine. After repeated cocaine injection, the mean scores of stereotyped behavior were increased with the number of injections. The level of NR1 subunit mRNA was obviously decreased in the striatum and cortices 24 h (early withdrawal) after a final injection following 14 days of subchronic administration. During the early withdrawal period, the amount of the NR1 subunit decreased in the nucleus accumbens, globus pallidus, and subiculum. In the dentate gyrus, the NR1 mRNA level significantly increased during early withdrawal in rats subchronically treated with cocaine. Levels of NR2B subunit mRNA were reduced in the cortices and striatum. During late withdrawal from cocaine, the level of NR2C subunit mRNA in the cerebellum was also reduced. These findings suggest that the disruption of NR1, NR2B, and NR2C subunits in the discrete brain regions occurs under the cocaine-related behavioral abnormalities and would be closely implicated in the initiation and expression of behavioral sensitization induced by repeated cocaine administration. Further studies on the changes in non-NMDA receptors are required to elucidate the biological significance of glutamate receptors for the mechanisms underlying the development of behavioral sensitization.

Anesthetics, Local↗
PubMed2002

Repeated cocaine administration increases GABA(B(1)) subunit mRNA in rat brain.

The effects of a single and repeated administration of cocaine on GABA(B) receptor subunit mRNA was investigated in rat brain by in situ hybridization. Following a single administration of cocaine, no significant change was observed in any brain regions examined, neither 1 h nor 24 h after administration. During repeated administration of cocaine, behavioral sensitization with increased stereotyped behavior was observed. A significant increase in the level of GABA(B(1)) mRNA was observed in the nucleus accumbens (11.4%), CA1 field of the hippocampus (16.8%), and thalamus (16.5%) 1 day after repeated administrations of cocaine for 14 consecutive days. The level of mRNA returned to the basal level 1 week after the final injection of repeated cocaine treatment. The observed changes in the mRNA level after the repeated cocaine may imply changes of GABA(B(1)) subunit in molecular mechanisms which underlie development of behavioral sensitization.

Animals↗