Biomedical subjects

Y Koshino

Publications and source records attributed to Y Koshino.

At least 37 records · Page 2Linked to original sources

PubMed1999

Polysomnographic and urodynamic changes in a case of obstructive sleep apnea syndrome with enuresis.

A 53-year-old female patient with obstructive sleep apnea syndrome was reported. She had complained of enuresis as well as a 15-year history of snoring, but she had no complaint of sleep and awake disturbance. Polysomnographic study showed repeated obstructive apnea and hypopnea with an apnea/hypopnea index of 52.6, and severe oxygen desaturation during sleep. On cystometography during sleep, the changing amplitude of the spike wave corresponds to the changes of respiratory efforts against a closed upper airway. The patient was treated successfully with imipramine and acetazolamide for the obstructive sleep apnea and enuresis. Apnea/hypopnea index, nocturnal oxygen desaturation, and sleep architecture were improved, and enuresis completely disappeared. Cystometrography during sleep showed that the average amplitude of the spike wave tended to be low. Percentage urinary volume during sleep compared with 24 h volume was significantly reduced. We considered that the enuresis was mainly related to increased intra-abdominal pressure produced by respiratory efforts and enhanced nocturnal urine production.

Acetazolamide↗

PubMed1999

Algorithm for treatment-refractory schizophrenia.

This algorithm for the treatment-refractory schizophrenia consists of nine lines. It starts from the revaluation of the diagnosis and checking the compliance. 'Apparent' non efficacy due to poor compliance must be distinguished from 'authentic' non efficacy. Patients with good compliance and non efficacy go on to the next line. Line 3 includes addition of another neurolepic, a neuroleptic in a decanoate form, addition of an anti-parkinsonian drug and reduction of the neuroleptic dose. Line 5 is the neuroleptic augmentation strategy. The options of line 7 are electroconvulsive treatment, very high-dose neuroleptics, an investigational protocol drug, and a drug-free period. Finally, line 9 includes an investigational protocol drug and a drug-free period.

Algorithms↗

PubMed1998

Clinical studies on three cases of the interval form of carbon monoxide poisoning: serial proton magnetic resonance spectroscopy as a prognostic predictor.

Three patients with the interval form of carbon monoxide (CO) poisoning were studied for associations between their clinical courses and serial changes on: (1) MRI; (2) EEG; (3) single photon emission computed tomography with N-isopropyl-p-[123I]iodoamphetamine ([123I]IMP SPECT); and (4) proton magnetic resonance spectroscopy ([1HIMRS) to evaluate their usefulness as prognostic predictors. A hyperintense area on MRI T2-weighted images and a hypointense area on T1-weighted images, appearing in the deep white matter, persisted for a prolonged period even after improvement of the clinical symptoms, and did not become an accurate indicator of clinical evaluation or prognosis. [1H]MRS studies with the volume of interest set in the frontal lobe white matter revealed increases in choline-containing compounds, and reductions of N-acetylaspartate in all cases. These findings normalized in one subclinical case over time. Distinctive findings in the severe cases included increased lactate in two cases showing akinetic mutism, with a difference in prognosis noted according to the degree and period of persistence of this increase. EEG findings were relatively well correlated with clinical symptoms in the early period, with a good correlation no longer consistent after a certain period was exceeded. [123I]IMP SPECT findings did not always reflectclinical symptomatology either. These results indicate that [1H]MRS is the most useful indicator in the clinical evaluation of patients with the interval form of CO poisoning.

Adult↗

PubMed1998

P300 and the thought disorder factor extracted by factor-analytic procedures in schizophrenia.

BACKGROUND: In order to clarify the clinical significance of P300 as a biologic marker that can reflect schizophrenic symptomatology, many previous studies have evaluated the relationship of P300 with the symptoms on the basis of a positive/negative dichotomy, but yielded inconsistent conclusions. Such a dichotomy has been criticized as being too reductionistic. Recently, most studies with factor-analytic procedures have extracted some symptom factors outside this dichotomy. Therefore, it is important to examine associations of P300 with the symptom factors extracted by these statistical analyses. METHODS: In the present study, the amplitudes of P300 were measured by using an auditory oddball paradigm for 73 schizophrenics whose psychopathology was assessed with the Positive and Negative Syndrome Scale (PANSS). RESULTS: The principal component analysis of the PANSS items revealed five factors labeled the thought disorder, negative, hostile/excitable, delusional/hallucinatory, and depressive factors. The score for the thought disorder factor correlated negatively with the amplitude of P300 recorded at Pz T5, and T6, but that for the other factors did not. CONCLUSIONS: These findings suggest that the reduction of P300 amplitudes recorded at the midline parietal and bilateral temporoparietal regions may be one of the electrophysiologic indices representing the thought disorder clinically observed in schizophrenia.

Acoustic Stimulation↗

PubMed1998

Differences in the effects of zolpidem and diazepam on recurrent inhibition and long-term potentiation in rat hippocampal slices.

We used the CA1 region of rat hippocampal slices to compare the effects of non-benzodiazepine zolpidem, which binds preferentially to the omega1 sites of gamma-aminobutyric acid A (GABA(A)) receptors, and of benzodiazepine diazepam, which binds equipotently to the omega1 and omega2 sites, on the hippocampal inhibitory mechanism and on long-term potentiation (LTP), a possible cellular mechanism for memory. First, 1 microM diazepam had an enhancing effect on recurrent inhibition by alveus stimulation of orthodromically-induced population spikes, but 1 microM zolpidem had no significant effect. Second, 1 microM diazepam blocked LTP induction of the population spikes, whereas 1 microM zolpidem had no such effect. Only at a higher concentration of 10 microM, zolpidem had a significant effect on recurrent inhibition and LTP. These findings suggest that only the omega2 sites are mainly involved in modulation of the hippocampal inhibitory mechanism and LTP, and that the low affinity of zolpidem for the omega2 sites may account for less memory impairment caused by zolpidem than by benzodiazepines.

Animals↗

PubMed1998

Non-familial olivopontocerebellar atrophy combined with late onset Alzheimer's disease: a clinico-pathological case report.

A 76-year-old woman with olivopontocerebellar atrophy (OPCA) presented with progressive intellectual deterioration. She showed cerebellar ataxia and muscle atrophy and weakness, and gradually developed generalized dementia with visuospatial disturbance. An autopsy revealed numerous senile plaques (SPs), neurofibrillary tangles (NFTs) and neuropil threads particularly in the CA1, subiculum and entorhinal cortex and to a lesser degree in the cerebral neocortex shown by immunostaining and specific silver impregnation techniques. The nucleus basalis of Meynert had numerous NFTs with fibrillary gliosis and neuronal cell loss. The basis pontis was markedly atrophied and the pontine nucleus had severe neuronal depopulation and gliosis. The pontine transverse fibers were demyelinated with their axons being fragmented. The cerebellar white matter was also severely degenerated. The striatum, Onuf's and intermediolateral nuclei of the spinal cord remained unchanged. Ubiquitin immunohistochemistry and Gallyas silver impregnation technique revealed oligodendroglial inclusions in the pontine nucleus, corticopontine tract, cerebral and cerebellar white matter. On double immunostaining of KP1 and ubiquitin, globular neurite SPs encircled by KP1-positive fibrous structures were found in the hippocampus and cerebral neocortex. The curly neurite SPs contained KP1-positive granules. The KP1-positive microglial cells were distributed widely in the cerebral white matter and HLA-DR-positive ones were found around the SPs. The present case showed generalized dementia compatible with Alzheimer's disease (AD) and had a pathologically limbic type of late onset AD. This is the first case where AD affected non-familial OPCA.

Aged↗

PubMed1998

Contribution of T-type calcium channels to afterdischarge generation in rat hippocampal slices.

To clarify the possible involvement of Ca2+ channel subtypes in epileptogenesis, the CA1 region of rat hippocampal slices was examined for the pharmacological effects of Ca2+ channel blockers on ictal-like afterdischarges (ADs) observed following the repetition of high-frequency electrical stimulation, as well as on interictal-like bursts of population spikes following single stimuli in the presence of bicuculline. Ni2+ and amiloride, which predominantly block T-type Ca2+ channels, suppressed the number of spikes in ADs at concentrations of these two channel blockers sufficient to eliminate this type of Ca2+ channel in acutely dissociated and cultured hippocampal neurons. On the other hand, neither the L-type Ca2+ channel blocker nifedipine nor the N-type Ca2+ channel blocker City, omega-conotoxin GVIA had any effect on the generation of ADs. In addition, none of these T-, L- and N-type channel blockers had any effect on the bicuculline-induced, interictal-like epileptiform discharges. We therefore conclude that the activation of T-type Ca2+ channels, which is distinct from the mechanisms involved in interictal activity, may play a causative role in the generation of ictal-like ADs.

Amiloride↗

PubMed1998

Abnormal functional connectivity in Alzheimer's disease: intrahemispheric EEG coherence during rest and photic stimulation.

Electroencephalography (EEG) coherence provides a measure of functional correlations between two EEG signals. The present study was conducted to examine intrahemispheric EEG coherence at rest and during photic stimulation (PS; 5, 10 and 15 Hz) in ten unmedicated patients with presenile dementia of the Alzheimer type (AD; mean age at onset 56 years). In the resting EEG, the AD patients had significantly lower coherence than gender- and age-matched control subjects in the alpha-1, alpha-2 and beta-1 frequency bands. The EEG analysis during PS also showed that the patients had significantly lower coherence in the frequency corresponding to PS at 10 and 15 Hz. In this study, the changes in coherence from the resting state to the stimulus condition (i.e. PS-related coherence reactivity) were examined. The patients were found to show significantly smaller coherence reactivity to PS at 5 and 15 Hz. These findings suggest that, in addition to the resting state, AD patients have an impairment of intrahemispheric functional connectivity during PS. They also suggest that AD shows a failure of PS-related functional reorganization.

Aged↗

PubMed1998

An autopsied case of Creutzfeldt-Jakob disease with the lateral geniculate body lesion showing antagonizing correlation between periodic synchronous discharges and photically induced giant evoked responses.

We reported an necropsy finding of a patient with Creutzfeldt-Jakob disease (CJD) who showed photo-stimulated giant spikes that simultaneously suppressed periodic synchronous discharges (PSD) and the loss of pupillary light reflex during the course of the illness. The necropsy revealed extensive gray and white matter lesions, and both the lateral geniculate body (LGB) and pregeniculate body were primarily affected. The superior colliculus, optic nerve and tracts were not affected. The cerebral cortices particularly of the occipital lobe were severely damaged. The Gennari line, however, was spared from lesion. The primary involvement of the LGB has been reported infrequently in CJD, however, it appears to be associated with the unusual electroencephalograph (EEG) feature of the present case. The pregeniculate lesion contributed to the loss of pupillary reflex. This finding indicates that the visual pathway may be involved in the mechanism of the generation of PSD in CJD.

Action Potentials↗

PubMed1998

Effect of flunitrazepam on sleep and memory.

Flunitrazepam's (FNZ) effect on sleep and memory 1 mg and 2 mg was investigated in 6 healthy volunteers (mean age 21.5 +/- 0.8 years) by polysomnography (PSG) and memory testing. A PSG was recorded on each study night. Memory testing was done before sleep (40 min after taking FNZ or placebo), and after waking (560 min after medication). Rapid eye movement (REM) latency was found to be prolonged on the FNZ 2 mg night (FNZ2N) compared to the baseline night (BN). Percentage of stage 2 sleep was increased in the FNZ2N as compared to BN, while REM percentage on both FNZ nights did not significantly differ from BN. The number of total REM and REM density were decreased in the FNZ2N compared to BN. Memory testing showed significant differences between before sleep and after waking on the FNZ2N. There was a significant correlation between the degree of impairment on memory testing and the rate of reduced REM density, but there was no significant correlation between degree of impairment on memory testing and the rate of increased non-REM sleep on the FNZ2N. The results of this study suggest that impairments in memory result from the dose of FNZ, and that there is a possibility of a relationship between memory disturbance and REM sleep suppression caused by this benzodiazepine.

Adult↗

PubMed1998

'Chiyamai', a panic-like disorder in woman divers from Hegura Island.

In Hegura Island, Japan, we have recently found female divers who suffer from a disorder called 'Chiyamai'. From interviews, questionnaires and temporarily proposed diagnostic criteria for Chiyamai, nine cases from 44 female divers interviewed, were diagnosed as having Chiyamai. Clinically, Chiyamai is characterized by a panic-like attack. Ten symptoms were observed during a panic-like attack, compared with 13 symptoms in a panic attack described in the DSM-IV. The average age at onset was 30 years and the average duration of illness was approximately 26 years. Several cases were so severe that the patients were unable to continue diving. Additionally, we report a typical case of Chiyamai, and discussed the similarities and differences between Chiyamai and anxiety disorders in the DSM-IV. We suggest that Chiyamai is a panic-like disorder specific to female divers from Hegura Island and that it is a result of heavy diving.

Adult↗

PubMed1998

Dipole analysis of epileptic source generator with manual zero potential shifting method.

The dipole tracing method is a technique whereby an electric source generator is estimated as an equivalent current dipole (ECD) based on potential distribution on the scalp. To estimate the electric source generator of low amplitude spikes, a manual zero potential shifting (MZPS) method was introduced in which a zero potential is set manually in dipole analysis. The subjects were three patients with localization-related epilepsy with temporal spikes. When low-amplitude spikes (< 50 microV) were analyzed by the conventional mean zero potential method, the dipolarity, an indicator of ECD reliability, had a low value and its locations were scattered. In contrast, when these low-amplitude spikes were analyzed by the MZPS method, ECD showed a high dipolarity value comparable to that obtained when high-amplitude spikes (> or = 50 microV) were analyzed by the mean zero potential method. Furthermore, the locations of the former ECD tended to converge and were almost identical to those of the latter ECD. These findings suggest the usefulness of the MZPS method in dipole analysis in terms of the dipolarity and ECD locations of low-amplitude spikes.

Action Potentials↗

PubMed1998

Reduced interhemispheric EEG coherence in Alzheimer disease: analysis during rest and photic stimulation.

The present study was conducted to examine interhemispheric electroencephalogram (EEG) coherence at rest and during photic stimulation (5, 10, and 15 Hz) in 10 patients with presenile dementia of the Alzheimer type (AD; mean age at onset, 56 years) and 10 sex- and age-matched control subjects. Compared with the control subjects, the AD patients had significantly lower interhemispheric coherence in the resting EEG for the delta, theta-2, alpha, and beta-1 frequency bands. EEG analysis during photic stimulation also showed that the patients had significantly lower coherence, irrespective of the stimulus frequency. In addition, when we examined the changes in coherence from the resting state to the stimulus condition (i.e., coherence reactivity), significant group differences were found at the brain region primarily involved in visual functioning; the patients had significantly smaller coherence reactivity to photic stimulation at 5 and 15 Hz over the posterior regions. These findings suggest that AD patients have an impairment of interhemispheric functional connectivity in both nonstimulus and stimulus conditions. The findings also suggest a failure of normal stimulation-related brain activation in AD.

Aged↗

PubMed1998

Dexamethasone modulates the expression of endothelin-1 and -A receptors in A7r5 vascular smooth muscle cells.

Endothelin-1 (ET-1) is synthesized and released by vascular smooth-muscle cells (VSMCs). Glucocorticoids induce the release of ET-1 from VSMCs into the medium. We investigated whether glucocorticoids modulate ET-1 action by an autocrine production of ET-1 in A7r5 VSMCs. Dexamethasone (100 nM) stimulated the release of ET-1 into the medium. Treatment with 100 nM dexamethasone for 24 h reduced the peak increase of intracellular free Ca2+ induced by ET-1 (100 nM) by 50%, an effect that was dose-dependently inhibited by the specific ET(A)-receptor antagonist FR139317. Scatchard plots of [125I]-ET-1 binding revealed that dexamethasone reduced the number of maximal ET-1 binding sites without altering their binding affinity. FR139317 reversed the decrease in ET-1 binding capacity induced by dexamethasone. Northern blot analysis revealed that dexamethasone increased the level of prepro-ET-1 messenger RNA (mRNA) and decreased the level of ET(A)-receptor mRNA. FR139317 prevented the decrease in the level of ET(A)-receptor mRNA induced by dexamethasone. Results indicate that dexamethasone downregulates ET(A) receptors in A7r5 VSMCs at the mRNA level, in part by the autocrine production of ET-1.

Animals↗

PubMed1998

Changes in work performances in obstructive sleep apnea patients after dental appliance therapy.

The effects of dental appliances on work performances of obstructive sleep apnea syndrome (OSAS) is not well examined. This study evaluated the polysomnographic and psychological findings before and after therapy. Nine patients were diagnosed OSAS by nocturnal polysomnography. The psychological batter, was performed from 13:00 to 14:00, which consisted of Uchida-Kraepelin psychodiagnostic test (U-K's test) and Bourdon's cancellation test (Bourdon's test). Approximately 3 months after the treatment, the examinations were performed. Apnea and desaturation index decreased significantly after the therapy. In addition, sleep architecture improved after the therapy compared with that before the therapy. Dysfunction of task performances, such as mean level of work amounts in U-K's test, mean error, mean performance time and mean deviation in Bourdon's test improved after therapy. We conclude that dental appliances therapy is effective not only to apnea but also to work performance in OSAS.

Adult↗

PubMed1998

Mitral valve prolapse and autonomic function in panic disorder.

We investigated the significance of mitral valve prolapse (MVP) and autonomic function in 121 patients diagnosed with panic disorder (PD). The incidence of MVP was higher in these patients (32.2%) than in the healthy controls (16.7%), but the difference was not significant. In the group with PD accompanied by depression, the MVP rate was 58.1%, significantly higher than the value of 25.7% observed in the PD patients without depression. The severity of MVP was mild; nearly all of the cases were silent, without cardiac murmur, and there was no problem with the left ventricular function. The coefficient of variation for R-R intervals on electrocardiograms (CV R-R) was smaller in patients with PD than in healthy controls. The CV R-R of PD patients was significantly lower in the group with MVP than in the group without MVP, suggesting a strong association with the parasympathetic nervous system. Since the CV R-R tended to decrease in the presence of depression, involvement of the parasympathetic nervous system was inferred.

Adolescent↗

PubMed1998

Aberrant functional organization in schizophrenia: analysis of EEG coherence during rest and photic stimulation in drug-naive patients.

EEG coherence provides a measure of functional correlations between two EEG signals. The present study was conducted to examine intrahemispheric EEG coherence at rest and during photic stimulation (PS) in 18 drug-naive patients with paranoid schizophrenia and 30 control subjects. Compared with the controls, the schizophrenic patients had significantly higher intrahemispheric coherence of the resting EEG for the delta band, although no significant group differences were found for other frequency bands. EEG analysis during PS showed that the patients also had significantly higher EEG coherence over the left posterior regions. In this study, we also examined the changes in intrahemispheric coherence from rest to the stimulus condition (i.e., PS-related coherence reactivity); the patients were found to show significantly smaller changes, with significant group differences being also confined to the posterior regions in the left hemisphere. These findings provide evidence that schizophrenic patients have abnormal EEG coherence in both resting and stimulus conditions and suggest more diffuse, undifferentiated functional organization within hemispheres. In addition, diminished coherence reactivity suggests a failure of PS-related functional reorganization in schizophrenia.

Adult↗

PubMed1998

Interhemispheric EEG coherence in never-medicated patients with paranoid schizophrenia: analysis at rest and during photic stimulation.

We assessed functional relationships between hemispheres by calculating interhemispheric EEG coherence at rest and during photic stimulation in 18 never-medicated patients with paranoid schizophrenia and 30 control subjects. Although no significant group differences were found in the resting EEG, the schizophrenic patients had significantly higher coherence on EEGs recorded during photic stimulation, compared to the control subjects. In this study, we also examined the changes in interhemispheric coherence from rest to the stimulus condition (i.e., stimulation-related coherence reactivity); the patients were found to show significantly greater coherence reactivity to photic stimulation. These findings provide further evidence that schizophrenic patients have a higher degree of interhemispheric functional connectivity and thus have less lateralized cerebral organization than normal subjects. Our results also suggest that schizophrenic patients have excessive functional reorganization between hemispheres in association with photic stimulation.

Adolescent↗