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Takuya Kojima

Publications and source records attributed to Takuya Kojima.

30 records · Page 2Linked to original sources

Family-based association study of markers on chromosome 22 in schizophrenia using African-American, European-American, and Chinese families.

Several studies suggest that loci at chromosome 22q11.2-q13 might be linked to susceptibility to schizophrenia. Here we performed family-based association studies on chromosome 22q using 12 DNA microsatellite markers in African-American, European-American, and Chinese pedigrees. The marker D22S683 showed significant linkage and association with schizophrenia in not only the European-American sample but also in a combined sample (European-American and Chinese samples). Notably, D22S683 is located nearby and between D22S278 and D22S283, which have shown linkage and association to schizophrenia in prior reports. However, we found no significant association for the African-American sample. In conclusion, our data provide further support for the idea that the region around D22S683 contains a susceptibility gene for schizophrenia.

Adult↗

Long-, intermediate- and short-acting benzodiazepine effects on human sleep EEG spectra.

The effects of 10 mg haloxazolam (HAX), 4 mg flunitrazepam (FNZ), and 0.5 mg triazolam (TRI), each administered for seven consecutive nights were studied in the sleep electroencephalograms (EEG) of 17 (six HAX, five FNZ and six TRI) healthy male student volunteers. Recordings of C3-A1 EEG data from one baseline night, three drug nights (first, fourth and seventh) and two withdrawal nights (second and fourth) were analyzed using a fast Fourier transformation method. All three drugs induced similar changes in the 0.5 Hz to 40 Hz power spectrum; namely (i) higher frequency (including the sigma and beta bands) activity increased and lower frequency activity reduced on the drug nights; (ii) the enhancement of sigma activity peaked during non-rapid eye movement sleep following the first administration and was maintained at high levels on all drug nights; (iii) beta activity increased through the night after administration of HAX and FNZ, but not TRI, which suggests a blood concentration level dependent increase of beta activity; and (iv) only HAX showed a residual effect on the fourth withdrawal night. These results indicate that (i) chronic administration of these three benzodiazepine derivatives produce similar profiles in sleep EEG spectral changes, with some differences depending on their half-lives and doses; (ii) the mechanism of sigma enhancement is sensitive to even the initial administration night of BDZ; and (iii) frequencies below and above the sigma band are less sensitive to BDZ and also show an increase through the night after administration, suggesting differences in the mechanisms reflected by these EEG frequency bands.

Adult↗

Exploratory eye movements during the Benton Visual Retention Test: characteristics of visual behavior in schizophrenia.

In order to investigate the relationship between the behavioral patterns and clinical symptomatology in schizophrenia, exploratory eye movements of schizophrenic subjects and healthy controls during the Benton Visual Retention Test were examined using an eye-mark recorder. The results were as follows: (i) with card 1, the number of eye fixations of schizophrenic subjects was fewer, and the total and mean eye scanning lengths of schizophrenic subjects were shorter than those of healthy controls; (ii) with card 3, almost none of the schizophrenic subjects looked at the blank area opposite the peripheral figure on the right; (iii) with cards 3, 5, 6 and 9 there were some schizophrenic subjects who did not look at the peripheral figures; (iv) with card 6, many of the schizophrenic subjects made stereotypical movements; (v) with card 9, schizophrenic subjects used a narrow vertical gaze to look at the large figure on the right. Based on these characteristics among the schizophrenic subjects themselves, factors such as longer eye scanning length, looking at peripheral figures without fail, and not making stereotypical movements were reflected directly in the results of the Benton test, while there was no relationship between the width of the vertical gaze and the Benton results. Correlations between visual behavior and some psychiatric symptoms were observed. The visual behavioral patterns of schizophrenic subjects were various according to the characteristics of the Benton figures, while those of normal subjects were always almost the same. It was suggested that these results were caused by disturbances of the mental attitude of schizophrenic subjects toward objects or environments.

Adult↗

Determining vulnerability to schizophrenia in methamphetamine psychosis using exploratory eye movements.

Patients with methamphetamine (MAP) psychosis whose psychotic symptoms continued after MAP withdrawal were observed at Saitama Prefecture Government Psychiatric Hospital. The purpose of the present study was to ascertain whether some of these MAP psychosis subjects have a vulnerability to schizophrenia. Forty-eight patients with MAP psychosis were divided into three groups based on clinical course: transient type, prolonged type and persistent type. Furthermore, the patients with the persistent type were divided into two groups: one group were moderately disturbed in social adaptive functioning and had Global Assessment Functioning scale (GAF) points >50, and the other group consisted of those who were severely disturbed in social adaptive functioning and who had GAF points of < or =50. These MAP patients were tested for exploratory eye movements, which are the vulnerability marker of schizophrenia, and were compared with 30 patients with schizophrenia and 30 healthy control subjects. The responsive search score of the severely disturbed group of patients of the persistent type was lowest, significantly lower than those of the transient type and the healthy controls. It did not differ from that of the schizophrenic subjects. These results suggest that the severely disturbed group of patients with the persistent type of MAP psychosis have a vulnerability to schizophrenia.

Adult↗

Relationship between attention and arousal level in schizophrenia.

The purpose of the present paper was to clarify the link between the attention and arousal level that supports the basis of the cognitive dysfunction in schizophrenia, by investigating the relationship between the simple reaction time and the closed-eye eye movements in 30 patients with schizophrenia and 20 healthy controls. In terms of closed-eye eye movements during the simple reaction time test, healthy controls showed an increase of s-type (small and slow) eye movements after the end of the preparatory interval (PI) in both regular and irregular series, while the patients with schizophrenia, particularly those in whom the cross-over phenomenon was observed, showed no changes and maintained a hyperarousal level during the regular PI test. These results indicate that the patients with schizophrenia could not maintain appropriate attention during the burden tasks and their hyperarousal level persisted. It is therefore suggested that there is a close relationship between attentional deficit and hyperarousal among patients with schizophrenia.

Adult↗

[Some resolutions in difficulties of postgraduate psychiatric education in Japan].

1. Board Certification System of Psychiatry There was a heated debate about "Postgraduate Psychiatric Education and Board Certification of Psychiatry" in the annual meeting for the Japanese Society of Psychiatry and Neurology held in Nagasaki in 1968 and in Kanazawa in 1969. The oppositions of young psychiatrists were as follows; 1) Issues of low cost of medical expense as government politics, social protect politics from psychiatric patients, and improper management of patients in mental hospitals should be dealt before making Board Certification System of Psychiatry. 2) Management of the Society of Psychiatry and Neurology dissatisfies many psychiatrists. Board Certification Systems started in many medical societies from 1969 to 1987. Main nine departments except psychiatry started the system. In 1987, the Japan Association of Chairmen of Department of Psychiatry of Medical Colleges (JACDPM) proposed a program for a postgraduate course. The Japanese Society of Psychiatry and Neurology (JSPN) formed the Committee on Psychiatric Education in 1987 and Working Group on Accreditation Program (WGAP) in 1991 under the Committee of Psychiatric Education. After intensive discussions on the Board certification, the WGAP reported a summary of their discussions in 1994. The essence of the WGAP recommended model for the Board of Association was as follows: Minimal Requirements Outline Training Period--three years psychiatric training after two years primary care experience by rotation through other departments. Field of Training--WGAP recommended that post-graduate training should be given at different kinds of institutes such as the department of psychiatry in medical schools, mental hospitals, out-patient mental clinics, community experiences in rehabilitation, day care, social clubs and health centers. Assessment--both oral examination and case reports are requested for evaluation and board certification. Re-evaluation every five years is required. However, there have been the following opinions and the Board Certification System has not been realized. 1) Making improvement in mental hospital is more important than starting Post-graduate Training and Organization for Board Certification of Psychiatry System (PTOBCP). 2) Starting PTOBCP makes professors in department of psychiatry in medical colleges give great power to suppress the right of personal management. 3) Financial support for postgraduate trainee and trainer is insufficient. Medical and psychiatric situations have changed from 2001 to 2002. 1) A neutral organization instead of academic societies will make Board Certification System in each department in the future. 2) Postgraduate educational rotation system (two years) will start in 2004. 3) Advertisement of being certificated by the Board has been possible. In recent situation, necessity for making of PTOBCP is increasing and many members of JSPN long to make it. In the 98th annual meeting, 2002 it was decided to make PTOBCP. 2. Post-graduate mandatory education system including psychiatry Recently, it was legally decided that post-graduate education for two years should be mandatory for every medical doctor who has passed a national board from 2004. Furthermore, psychiatric training should be mandatory for every rotating resident. The period of psychiatric training is one, two or three months, which depends upon each teaching hospital. It is epoch-making that every resident should receive psychiatric training, however, in other words, it means that psychiatric education in Japan will be re-evaluated through such a new training system.

Certification↗

Influence of arousal level for functional magnetic resonance imaging (fMRI) study: simultaneous recording of fMRI and electroencephalogram.

Simultaneous recording of functional MRI (fMRI) and electroencephalogram (EEG) has been applied to several clinical fields, making it possible to monitor the arousal level of the subject during a cognitive task. The study confirmed that activated cerebral areas were different between high and low arousal levels during the smooth-pursuit eye movement task. When arousal level was high, activations in the parietal eye field, frontal eye field (FEF), supplementary eye field (SMA), visual fields (V1) and occipito-temporal junction (V5) were found. In contrast, when arousal level was low, activations were found only in V1 and FEF. The results indicate that the monitoring of the arousal level of subjects using fMRI and EEG recordings simultaneously is crucial for detecting cortical activations during a cognitive task.

Arousal↗

Effects of low-dose ketamine on neuropathic pain: An electroencephalogram-electrooculogram/behavioral study.

The aim of the present study was to clarify the neurophysiological changes associated with analgesic and behavioral effects of low-dose ketamine HCl in patients suffering from chronic neuropathic pain. Ten in-patients with neuropathic pain participated in this single-blind, placebo-controlled study after giving written informed consent. Following intravenous injections of a saline solution (placebo), three bolus injections of 5 mg ketamine HCl were administered at 5 min intervals. Changes in pain perception were assessed using a numerical rating scale for pain. Behavioral changes, including psychotomimetic effects, were assessed using the Brief Psychiatric Rating Scale (BPRS). Electroencephalograms (EEG) and electrooculograms (EOG) were recorded continuously throughout the testing period. One minute EEG and closed-eye eye movements were quantified. The effects of ketamine were evaluated by comparing the neurophysiological and behavioral parameters obtained from the placebo and ketamine trials. Pain reduction was significantly correlated with ketamine-induced changes in hallucinatory behavior and excitement as measured by the BPRS. Ketamine injections caused a significant decrease in the EEGalpha amplitude without an accompanying reduction in EEG frequency. The EEGalpha amplitude reduction at the right central electrode was significantly related to subjective pain relief. Subanesthetic doses of ketamine significantly decreased rapid eye movements, but did not initiate slow eye movements. In conclusion, the present EEG-EOG/behavioral results indicate that ketamine-induced failure of neural integration between cortical-subcortical regions induces psychotic symptoms and alters pain perception on neuropathic pain.

Aged↗

Effects of a benzodioxan derivative MKC-242 on the firing activity of the dorsal hippocampus CA1 pyramidal neurons in awake and urethane- anaesthetized rats: in vivo electrophysiological evidence for a 5-HT 1A agonistic property.

The aim of the present in vivo study was to determine whether a benzodioxan derivative MKC-242, (S)-5-[3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole hydrochloride, possesses an agonistic activity at postsynaptic serotonin (5-HT)1A receptors in the rat hippocampus when administered systemically. We examined the effects of acute administrations of MKC-242 on the firing activities of dorsal hippocampus CA1 pyramidal neurons. In quiet awake rats, s.c. administrations of MKC-242 significantly decreased the spontaneous firing activity in a dose-dependent manner at doses of 0.3-6 mg/kg. In urethane-anaesthetized rats, i.v. injections of MKC-242, at cumulative doses of 0.3-3 mg/kg, also significantly and dose-dependently inhibited the firing activity induced by microiontophoretically applied quisqualate. These decreasing effects were antagonized by the selective 5-HT1A antagonists WAY-100135 (5 mg/kg, s.c.) and WAY-100635 (0.2 mg/kg, s.c. to the awake rats and 0.4 mg/kg, i.v. to the anaesthetized rats), thereby confirming that MKC- 242 decreased the firing activities by stimulating 5-HT1A receptors. The selective depletion of 5-HT produced by the 3-d administration of the 5-HT synthesis inhibitor, parachlorophenylalanine (500 mg/kg.d, i.p.), did not affect the decreasing effect of MKC-242 in the awake animals, indicating that postsynaptic 5-HT1A receptors mediated the decreasing effect. The present results provided the first in vivo electrophysiological evidence that MKC-242, when systemically administered, exerts a 5-HT1A agonistic action at the postsynaptic level.

Journal Article↗

Correlation between quantitative-EEG alterations and age in patients with interferon-alpha-treated hepatitis C.

The authors recently observed alterations in the quantitative EEG findings in patients with chronic hepatitis C who were treated with interferon-alpha (IFN-alpha). However, the factors that influenced such EEG alterations remain unclear. The authors evaluated the correlation between QEEG alterations that occurred during IFN-alpha treatment and the age of 98 patients with chronic hepatitis C. These patients underwent blind, prospective, and serial quantitative EEG examinations. IFN-alpha was administered intramuscularly at 9 x 10 IU daily for the first 4 weeks and then three times per week for the next 20 weeks. Serial EEGs were obtained before, at 2 and 4 weeks, and at 2 to 3 days after the treatment. The absolute powers of each frequency band at different stages of the treatment were determined by QEEG. The ages of the patients were classified into five groups: 20 to 29, 30 to 39, 40 to 49, 50 to 59, and > or =60 years. The relationship between the alterations in power values and age was statistically evaluated. As the age of the patients increased, the alterations in power values for the slow waves, alpha 2, and fast waves during IFN-alpha treatment became more remarkable, and significant (repeated-measure analysis of variance; P < 0.0001). The alterations of EEG occurring during IFN-alpha treatment were marked in older patients.

Adult↗