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Biomedical subjects

K Isaki

Publications and source records attributed to K Isaki.

At least 37 records · Page 2Linked to original sources
PubMed1996

Pathology of the cerebellar dentate nucleus in sporadic olivopontocerebellar atrophy: a morphometric investigation.

The pathology of the cerebellar dentate nucleus was investigated by morphometric methods in three patients with sporadic olivopontocerebellar atrophy (sOPCA), and the results were compared to specimens from three subjects without neurological disease (controls). The size of dentate neurons; the number of small and large neurons (50-199 microns2 and larger than 200 microns2, respectively) at rostral, middle, and caudal levels; nerve cell density; total volume of the gray band; and total nerve cell number, were estimated with an image analyzer applied to serial 20-microns-thick sections of one celloidin-embedded cerebellar hemisphere. The number of small neurons in patients with sOPCA was significantly increased at the rostral level while the number of large neurons showed large inter-individual variations. Dentate neurons also showed various qualitative changes such as atrophy and hypertrophy. The nerve cell density in the dentate nucleus was 1.7 times higher in the patients than in the controls. However, the total volume of the gray band was reduced to one-half of that in controls. There were no differences in the total nerve cell number between the patients and controls. This reduction in size of the dentate gray matter in patients with sOPCA may result from the disappearance of afferent nerve fibers originating from Purkinje cells, inferior olivary neurons, and pontine neurons.

Aged↗
PubMed1995

Neurons, intracellular and extracellular neurofibrillary tangles in subdivisions of the hippocampal cortex in normal ageing and Alzheimer's disease.

Unaffected neurons, intracellular neurofibrillary tangles (I-NFTs) and extracellular NFTs (E-NFTs) in six normal subjects and six patients with Alzheimer's disease (AD) were morphometrically evaluated in eight subdivisions of the hippocampal cortex, using the Gallyas silver impregnation technique modified by the application of hematoxylin and eosin. The subdivisions examined included CA1-4, prosubiculum (PRO), subiculum and presubiculum (PRE), parasubiculum (PARA) and the entorhinal cortex (ENT). In the AD patients, the number of unaffected neurons in ENT, CA1, PRO and PARA was significantly decreased to one-quarter to two-thirds of that of the normal aged subjects. These four subdivisions in the AD patients had a greater number of both I- and E-NFTs. There were no significant differences in the total number of unaffected neurons, I- and ENTs between the AD patients and normal aged subjects for all the subdivisions. These findings suggest that neuronal loss in the hippocampal cortex in AD is almost entirely due to NFT formation. Furthermore, with regards to neuronal loss and NFT formation, there were two different subdivision groups in the AD patients. One group was composed of severely affected subdivisions (ENT, CA1, PRO and Para) and was distinct from the other group which was composed of mildly affected subdivisions (CA4, CA3, CA2 and PRE). Each subdivision in the normal aged subjects belonged to the mildly affected group as seen in the AD patients. These findings indicate that both neuronal loss and NFT formation associated with normal ageing and with AD are not only quantitatively but also qualitatively different.

Aged↗
PubMed1995

Quantitative EEG in never-treated schizophrenic patients.

To clarify whether patients with schizophrenia still show EEG slowing in the absence of psychopharmacological treatment, EEG was analyzed in 20 acute never-treated schizophrenics and 20 age-matched healthy controls using the computerized wave-form recognition method. Compared to controls, schizophrenics had more fast theta (6-8 Hz) and slow alpha (8-9 Hz) activity, and less fast alpha activity (9-13 Hz). The average EEG frequency at O1 correlated negatively with total and positive symptom scores on the BPRS in the schizophrenic group. These findings confirm that the frequency of alpha rhythm is slowed in schizophrenia and that this slowing is possibly related to the expression of psychopathology in this disorder.

Adult↗
PubMed1995

Serial proton magnetic resonance spectroscopy in a patient with the interval form of carbon monoxide poisoning.

Serial proton magnetic resonance spectroscopy (1H-MRS) studies were performed from immediately after the appearance of sequelae in a patient with the interval form of carbon monoxide (CO) poisoning. The volume of interest was set over the frontal lobe white matter. In the early period a persistent increase in choline was found, which was thought to reflect the course of progressive demyelination. The appearance of lactate and decrease in N-acetylaspartate reflected the point at which neuron injury became irreversible. These were followed later by the finding of irreversible changes on MRI and single photon emission computed tomography. The findings suggest that 1H-MRS may be a useful modality to determine neuron viability and prognosis early in the course of the interval form of CO poisoning.

Brain Diseases↗
PubMed1993

In vivo proton magnetic resonance spectroscopy study on premature aging in adult Down's syndrome.

Proton magnetic resonance spectroscopy (1H-MRS) was performed in a group of 18 adult patients with Down's syndrome (DS) aged 20-46 years, and the peak area ratios (NAA/Cr, Cho/Cr, NAA/Cho) of N-acetylaspartate (NAA), total creatine (Cr), and choline-containing compounds (Cho) calculated separately in the patients in their 20's, 30's, and 40's. In age-matched healthy control groups, there were no significant age-related changes in any of the peak area ratios. In contrast, in the DS group, although the relative amount of NAA (NAA/Cr) showed no significant change with increasing age, the relative amount of Cho (Cho/Cr and NAA/Cho) was significantly increased in the 40's group. At least as judged by MRI, few age-related general morphological changes such as brain atrophy were apparent in the third, fourth, and fifth decade groups. However, the MRI findings considered together with the age-related changes in the peak area ratios suggest that in DS patients in the fifth decade metabolic abnormalities such as degradation and/or rapid synthesis of brain cell membrane may occur prior to neuronal loss and degeneration.

Adult↗
PubMed1993

Frontal intermittent delta activity in schizophrenic patients receiving antipsychotic drugs.

FIRDA was found in 14 EEGs recorded from 338 schizophrenic patients receiving antipsychotic drugs, although they showed no FIRDA in the baseline EEG. The daily dose of antipsychotic drugs when FIRDA was found was larger than when FIRDA disappeared. FIRDA was assumed to be induced by relatively high doses of antipsychotic drugs. Thus, the effect of antipsychotic drugs should be added to the list of differential diagnoses associated with FIRDA. FIRDA did not correlate with the baseline psychopathology of schizophrenic patients. Patients without FIRDA tended to respond poorly to antipsychotic drugs in terms of negative symptoms. Improvement of positive symptoms in FIRDA patients was not as remarkable as in patients without FIRDA.

Adolescent↗
PubMed1993

The influence of light drowsiness on the latency and amplitude of P300.

Light drowsiness affected the P300 obtained with a standard auditory oddball paradigm. A simple two-tone discrimination paradigm was used. The frequent nontarget stimuli were 1000 Hz pure tones and the infrequent target stimuli were 2000 Hz pure tones. The subjects were required to press a button whenever infrequent target tones were presented. With light drowsiness, P300 increased in latency and decreased in amplitude, but the counts of infrequent tones remained correct nevertheless. It was concluded that electrophysiological brain function differs in the light drowsy and awake states. In studies on P300, it is essential to rule out light drowsiness to obtain valid P300 amplitudes and latencies.

Adult↗
PubMed1992

A survey of tardive dyskinesia in psychiatric inpatients in Japan.

To investigate the prevalence of tardive dyskinesia (TD) in a group of psychiatric patients receiving low doses of antipsychotic drugs, we examined 647 Japanese inpatients (361 men and 286 women) with a mean age of 49.8 years, receiving a mean dose of antipsychotic drugs of 276.8 mg of chlorpromazine equivalent. TD was diagnosed according to the criteria of Schooler and Kane with the Abnormal Involuntary Movement Scale. The overall prevalence of TD was 22.3%. Mild TD was found in 67.4% of TD patients, moderate TD in 29.2%, and severe TD in 3.5%. The TD patients were older (59.0 years) than those without this condition (47.2 years). The prevalence of TD increased with advancing age until the 7th decade, when it reached a plateau. The dose of daily antipsychotic drugs was lower in the TD patients (207.6 mg) than in the patients without TD (296.6 mg). The duration of primary illness was longer in the TD patients (28.9 years) than in the patients without TD (20.4 years). Patients receiving antiparkinsonism drugs showed TD less frequently (20.7%) than those not receiving such drugs (31.0%). No significant associations were found between the presence of TD and sex or primary illness.

Adolescent↗
PubMed1992

Cytoskeletal protein abnormalities in patients with olivopontocerebellar atrophy--an immunocytochemical and Gallyas silver impregnation study.

A highly sensitive silver technique for glial cytoplasmic inclusions (GCI) in olivopontocerebellar atrophy (OPCA) was applied to tissues from 15 patients with neurodegenerative disorders including OPCA, Joseph disease, Alzheimer's disease (AD), Huntington's chorea, Pick disease and three control non-neurological subjects. Brain tissue from both OPCA and AD impregnated positively. Neurons, astroglia and oligodendroglia in the putamen, pontine nucleus and inferior olivary nucleus all impregnated in addition to white matter oligodendroglia. Neuronal inclusions in the pontine nucleus appeared as compact or fibrillary masses, and GCI-bearing oligodendroglia and astrocytes showed homogeneously impregnated somata. The myelinated pontocerebellar tract and the white matter surrounding the inferior olivary nucleus contained a small number of impregnated nerve fibres with a hollow structure, which resembled the myelin sheath. Immunocytochemical studies to clarify these argyrophilic structures in the OPCA subjects employed paired helical filament (PHF), microtubule associated proteins (MAPs), MAP1, MAP2, MAP5, tau, ubiquitin, neurofilament (200 or 70 kilodaltons) and myelin basic protein (MBP) antisera. GCI-bearing white matter oligodendroglia expressed PHF, tau, MAP5 and ubiquitin immunoreactives and non-argyrophilic astroglia were positive for MAP5 antiserum alone. In the putamen, pontine nuclei and inferior olivary nuclei, impregnated neurons as well as the GCI-bearing oligodendroglia immunostained with PHF, tau, MAP5 and ubiquitin antisera and impregnated astroglia were also immunoreactive to these antisera except for being tau negative in the putamen. Silver impregnated nerve fibres showed only MBP immunoreactivity. These findings indicate that the argyrophilia in the OPCA subjects closely correlates with PHF and tau immunoreactivities.

Aged↗
PubMed1992

Quantitative EEG of elderly schizophrenic patients.

To investigate the brain function of elderly schizophrenic patients, quantitative EEGs of such patients were compared with those of healthy elderly controls. In schizophrenics, increases in delta and slow theta (4.0-6.0 Hz) waves were thought to be due to the influence of antipsychotics. Characteristic EEG features of these patients included the following: 1) more fast theta (6.0-8.0 Hz) wave was observed, with less alpha wave faster than 9.0 Hz, 2) the reduction in alpha 3 (10.0-11.0 Hz) wave was limited to the frontal regions. The present EEG findings are thought to characterize the traits of the subtype of chronic severe schizophrenia. The reduction in alpha 3 wave in the frontal regions may be one expression of the hypofrontality of schizophrenia.

Age Factors↗
PubMed1992

[Cytoskeletal proteins abnormalities in olivopontocerebellar atrophy].

A highly sensitive silver technique for glial cytoplasmic inclusions in olivopontocerebellar atrophy (OPCA) was applied to 15 subjects with neurodegenerative disorders including 4 patients with OPCA, 4 patients with Joseph disease and with 3 normal control subjects, and the argyrophilic structures in the OPCA cases were immunocytochemically examined. As a result, the argyrophilic structures were found in the OPCA cases and Alzheimer cases. The argyrophilic structures included the white matter oligodendroglia, and neurons, astroglia and oligodendroglia in the putamen, pontine nucleus and inferior olivary nucleus. The pontocerebellar tracts and the surrounding white matter of the inferior olivary nucleus contained a small number of argyrophilic nerve fibers with a hollow structure, which were interpreted as myelin. Immunocytochemistry demonstrated that the oligodendroglia in the white matter had immunoreactivities to an paired helical filament (PHF), microtubule associated protein 5 (MAP5), tau and ubiquitin antiserum, and the astroglia in the white matters had an immunoreactivity to a MAP5 antiserum. In the putamen, pontine nucleus and inferior olivary nucleus, in addition to the immunoreactivities observed in the oligodendroglia, the neurons were immunoreactive for PHF, MAP5, tau and ubiquitin antisera, and the astroglia had the same immunoreactivities as the neurons except for being tau negative in the putamen. The nerve fibers in the pontocerebellar tract and inferior olivary nucleus capsule were strongly positive for myelin basic protein and negative for PHF antiserum. These findings indicate that the Gallyas positive argyrophilia in the OPCA subjects is closely associated with PHF or tau.

Aged↗
PubMed1991

A long-term outcome study of tardive dyskinesia in patients on antipsychotic medication.

We followed 28 patients with tardive dyskinesia (TD) (eight men and 20 women, mean age 55.1 years) for 11-12 years to elucidate the long-term outcome of TD. All the patients received their physicians' choice of therapy, mainly comprising antipsychotics. The severity of TD was assessed at 5 and 11-12 years after the baseline evaluation. TD did not disappear in any patient. The severity of TD was unchanged in 39.3%, and improved in 17.9% despite continuous treatment with low doses of antipsychotics (mean 221.4 mg chlorpromazine equivalent daily). TD fluctuated in 21.4% and worsened in only 21.4%. Outcome was not correlated with patient sex or age, duration of primary illness, dosage of antipsychotics, or changes in dosage. The initial severity of TD showed some relationship to outcome. The number of bodily areas affected by TD increased in some patients with unchanged TD severity.

Adult↗
PubMed1991

Sex concordance in proband-relative pairs with schizophrenia.

Sex concordance rates were investigated in 278 schizophrenic probands, who had at least one first-degree relative with schizophrenia, in order to find out whether the illness affects the same sex more often than the opposite sex when two close relatives become ill. No such unusual concordance rates were found in proband-relative pairs with schizophrenia. When 118 of the 278 probands were examined who had at least one parent with schizophrenia, the morbidity risk for schizophrenia in siblings of the same sex as the schizophrenic probands was significantly higher than that found in siblings of the sex opposite that of schizophrenic probands.

Adolescent↗