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Biomedical subjects

Y Hishikawa

Publications and source records attributed to Y Hishikawa.

At least 73 records · Page 4Linked to original sources
PubMed1996

Electrophysiological evidence suggesting that sensory stimuli of unknown origin induce spontaneous K-complexes.

The present study was performed to determine whether or not spontaneous K-complexes are induced by sensory stimuli. In the first part of the present study, sound stimuli were prescribed during sleep in 7 healthy, young, adult subjects. EEG segments in stage 2 sleep were averaged separately according to the presence or absence of an evoked K-complex appearing after each stimulus. The sound stimulus induced N100 and P200 components in averaged EEGs regardless of K-complex appearance. The appearance of N100 and P200 components was considered to be an indicator of the presence of sensory stimuli. In the second part of the present study, EEG segments in stage 2 sleep containing an evoked K-complex or spontaneous K-complex were separately averaged with respect to the peak of N300, one of the main components constituting the K-complex. Small negative and positive components were found just before the main components of spontaneous K-complexes in averaged EEGs. These two components were judged to correspond to N100 and P200 components induced by the sound stimulus, as they appeared just before the main components of the spontaneous K-complex with almost the same lag time between the two components, or between each of the two components and the main components of K-complex, as in the case of N100 and P200 appearing just before the evoked K-complex. The present findings suggest that the spontaneous K-complex is not a spontaneous phenomenon, but that it is induced by sensory stimuli, probably of extracerebral origin.

Adult↗
PubMed1996

Prognostic significance of proliferating cell nuclear antigen (PCNA) in squamous cell carcinoma of the esophagus.

Proliferating cell nuclear antigen (PCNA) has been shown to be of prognostic significance in some gastrointestinal tumors. Immunohistochemical analysis was performed to determine whether PCNA is useful for predicting the outcome of patients with squamous cell carcinoma of the esophagus. Using a mouse monoclonal antibody, PC 10, the expression of PCNA was studied in resected squamous cell carcinomas of the esophagus from 59 patients who had undergone curative esophagectomy. None had received any preceding therapy. The proliferation rate was assessed in terms of the percentage of the PCNA-positive nuclear area relative to the total area of cancer nuclei using a cell analysis system (CAS). Clinicopathological variables including PCNA staining were assessed in relation to prognosis. Survival rate was obtained by the Kaplan-Meier method. The PCNA indices (percentage of the positive nuclear area) of the tumors varied from 4.4% to 96.2%. Among the clinicopathological variables, only tumor size (5 cm) and depth of invasion were correlated significantly with PCNA index (P<0.05). Microscopically, PCNA was stained in non-keratinized cells but not in keratinized cells. However the histological grade was not correlated with PCNA index. The survival rate was significantly worse in patients with high PCNA indices (> or = 40%) than in those with low indices (<40%) (P<0.05). However, multivariate analysis revealed that PCNA index was not an independent prognostic factor.

Aged↗
PubMed1996

A quantity of stereotyped behavior of ddY mice induced by low-dose methamphetamine.

It is reported that high-dose methamphetamine (8 mg/kg) induces stereotyped behavior in ddY mice in an open field, but it is still not certain that low-dose methamphetamine (less than 2 mg/kg) can induce the stereotyped behavior in ddY mice in a narrow space. In order to investigate the problem, we evaluated the quantity of stereotyped behavior of ddY mice by using a mouse wheel-running apparatus. In this method, we have come to recognize an increase in the stereotyped behavior depending on the dose of methamphetamine and the reverse-tolerance phenomenon as a decrease in the wheel-revolution counts. The present findings indicate that low-dose methamphetamine can promote stereotyped behavior in ddY mice under conditions in which the ambulation is restricted to a narrow wheel space.

Animals↗
PubMed1996

On the EEG component waves of multi-infarct dementia seniles.

Component waves of EEGs led from the F3-A1, C3-A1, O1-A1, and O2-A2 scalp regions of 24 multi-infarct dementia seniles (MID) patients (ages 58 to 85 years, average 73.3 years) and eight to 19 normal, healthy, adult (NA) subjects were obtained by autoregressive component analysis. Some differences in the component waves were demonstrated between the two groups of subjects. (1) The characteristics of the EEG component waves, including the natural, damping, and resonance frequencies, their power, regularity, etc. were determined, and compared between MID patients and NA subjects. (2) No significant difference was found between male and female patients in the occurrence rate of 11 types of component waves. (3) On the average, the alpha wave frequency was lower in MID patients. (4). Slow alpha waves (7.5 to 9.4 Hz) of MID patients were superior to those of NA subjects, whereas typical alpha waves (9.5 to 11.4 Hz) were inferior to those of NA subjects. (5) The power of alpha waves in the F3-A1 and C3-A1 regions of MID patients was superior to that of NA subjects, whereas the result was reversed in the O1-A1 and O2-A2 regions. However, there was less regularity of alpha waves in all regions among MID patients. (6) The theta wave frequency in all regions was higher in MID patients than in NA subjects. (7) Both the power and regularity of theta waves of MID patients were superior to those of NA subjects in all regions. (8) The average number of delta waves that appeared in the O1-A1 and O2-A2 regions was larger in MID patients than in NA subjects. EEG were led from the F3-A1, C3-A1, O1-A1, and O2-A2 scalp regions of multi-infarct dementia seniles (MID) patients, who had sleep disorders, such as reversed day-time sleep patterns or irregular sleep-wake patterns, frequently accompanied by behavior disorders, such as wandering, violent behavior, and/or delirium. Examination by the method of EEG pattern discrimination revealed some differences in EEG component waves in comparison with normal, healthy, adult (NA) subjects.

Adult↗
PubMed1996

Favorable effect of transcranial electrostimulation on behavior disorders in elderly patients with dementia: a double-blind study.

The efficacy of transcranial electrostimulation for sleep-wake and behavior disorders in elderly patients with dementia was tested in a double-blind study. The subjects were 27 inpatients with multi-infarct dementia (12 males and 15 females, aged 58-86). They were randomly divided into two groups: active treatment (n = 14) and placebo treatment (n = 13). For electrostimulation, a device (HESS-100) was used which delivered repetitive rectangular electric pulses of 6-8 V at increasing frequencies from 6 to 80 Hz, each pulse lasting 0.2 ms and with a root mean square value of 256-530 microA. Electrostimulation was performed for 20 minutes from 10:00 h every morning. The active or placebo treatment was performed for 2 weeks in each group. The electrostimulation was significantly effective in behavior disorders such as wandering or nocturnal delirium, and decreased motivation during the daytime. It was also effective in improving night sleep. Electroencephalograms confirmed increased vigilance levels in the daytime both during and after the treatment.

Aged↗
PubMed1995

K-complex evoked in NREM sleep is accompanied by a slow negative potential related to cognitive process.

Evoked cortical responses to two kinds of auditory stimuli (rare and frequent) were analyzed to determine whether or not a K-complex evoked in stage 2 of NREM sleep is accompanied by some endogenous cognitive components of the event-related potential. All the 7 subjects examined in this sleep state failed to provide the correct behavioral response to auditory stimuli, but a K-complex was evoked more frequently by rare stimuli than by frequent stimuli. EEG segments in stage 2 were averaged separately according to the presence or absence of K-complexes emerging just after the stimulation. In cases where K-complexes did not emerge, a long-lasting negative potential of relatively low voltage appeared in the difference wave, which was obtained by subtracting the averaged EEG for frequent stimuli from that for rare stimuli. In cases where K-complexes emerged, a similar long-lasting negative potential of large amplitude appeared in the difference wave. These data may indicate that a K-complex evoked by an external stimulus is accompanied by a potential related to a cognitive process, which appears with greater amplitude in cases where a K-complex is evoked.

Acoustic Stimulation↗
PubMed1995

[Effects of chronic ethanol intake on sugar chain structures of IgG in mice].

IgG is an N-glycosylated glycoprotein, and is secreted from B lymphocyte. Transferrin is also an N-glycosylated glycoprotein secreted from hepatic cell. We have investigated, by lectin-ELISA method, reactivities of sugar chain structures, which are Gal (beta 1, 4) GlcNAc, Fuc (alpha 1, 3 or 6) Gal, NeuAc (alpha 2, 6) Gal, galactose, poly mannoses and NeuAc (alpha 2, 3) Gal, in IgG or transferrin of ddY mice that were given ethanol solution for 3 weeks. In the investigation, we have found that the all reactivities of sugar chain structures in IgG and transferrin remarkably reduced. We have also found that Lewis-X (Gal (beta 1, 4) GlcNAc (3, 1 alpha Fuc)-), which is functional sugar chain structure in the IgG, was markedly reduced with dose-dependent manner. These findings indicate that ethanol decreases activities of glycotransferases in some cells which produce and secrete N-glycosylated glycoproteins. It has been reported that human erythrocyte has also N-glycosylated glycoproteins in the membrane, and its sialic acid and galactose are reduced after chronic ethanol intake. The past and present findings indicate that sugar chain structures of N-glycosylated glycoproteins in both serum and cell membranes are reduced after chronic ethanol intake. Though functions of sugar chain structures of N-glycosylated glycoproteins remain unclear, if functional structures like Lewis-X exist in N-glycosylated glycoproteins, the change of the sugar chain structures may have some relations to diseases occurring after chronic ethanol intake.

Alcoholism↗
PubMed1995

[Rest-activity and body-temperature rhythm disorders in elderly patients with dementia--senile dementia of Alzheimer's type and multi-infarct dementia].

We simultaneously monitored rest-activity and body temperature (BT) rhythm in demented patients with sleep and behavior disorders using ambulatory wrist-worn actigraph and long-term monitoring system for 5-7 consecutive days. Subjects consisted of 19 patients with senile dementia of Alzheimer's type (SDAT) (M/F = 7/12, mean age = 71.7 years), 16 patients with multi-infarct dementia (MID) (M/F = 9/7, mean age = 75.2 years) and 9 normal controls (M/F = 4/5, mean age = 70.4 years). Both dementia groups showed a significant increase in percentage of nighttime activity. In the SDAT group, a significant positive correlation between the degree of dementia and total activity was observed, but not observed in the MID group. A significant high amplitude of BT rhythm was observed in the SDAT group comparing that in the MID or the control group. These findings indicate that the SDAT patients had a disrupted rest-activity rhythm with the severity of intellectual deterioration and increased night activity, while the circadian BT rhythm was remarkably well preserved, i.e. there was a dissociation between rest-activity and BT rhythms in the SDAT group. On the other hand, the disruption of the rest-activity and BT rhythm in the MID patients was characterized by a concomitant decrease of amplitude, which seems to have no relation with the severity of dementia. Different mechanisms could be involved in characteristic disruption of the circadian rhythms in the 2 dementia groups.

Aged↗
PubMed1995

Physiology of REM sleep, cataplexy, and sleep paralysis.

The main neural structures generating muscle atonia and other phenomena characteristic of REM sleep are present in dorsolateral portions of the pons in the brainstem. Occurrence of REM sleep and the NREM-REM sleep cycle are probably determined by a balance or interaction between the cholinergic and cholinoceptive REM sleep-on neuronal populations and the monoaminergic REM sleep-off neuronal population. Neural activities producing generalized muscle atonia in REM sleep originate mainly in dorsolateral portions of the pontine reticular formation, descend through the medulla and spinal cord, and inhibit the motoneurons in the brainstem and spinal cord, bringing about postural atonia. Cataplexy and sleep paralysis are pathological, dissociated manifestations of the generalized muscle atonia characteristic REM sleep. Cataplexy is triggered by emotional stimuli, probably through activation of the neural structure generating the muscle atonia of REM sleep. During long-lasting cataplectic attacks, narcoleptic humans often experience sleep paralysis and vivid hypnagogic hallucinations in the latter sleep state. Sleep paralysis is caused by the marked dissociation between level of alertness and muscle atonia that often occurs in SOREM sleep episodes. Frequent SOREM sleep episodes in narcoleptic humans and dogs may occur when some of the neural mechanisms producing wakefulness and/or NREM sleep that normally inhibit the occurrence of REM sleep are abnormally weak, or when neural mechanisms facilitating the occurrence of REM sleep are hypersensitive or hyperactive, or both. Both abnormalities may contribute to the occurrence of SOREM sleep episodes and sleep paralysis, and also to the emotional triggering of cataplexy. Frequent occurrence of SOREM sleep episodes seems to be prerequisite but not sufficient for the occurrence of cataplexy. Some additional neural activities induced by emotion also contribute by inhibiting and/or activating the disturbed neural mechanisms related to SOREM sleep episodes. These abnormalities in neural mechanisms probably involve hypersensitivity or hyperactivity of muscarinic cholinergic and/or cholinoceptive neuronal populations in the pontine and suprapontine structures, and/or abnormally decreased activity of noradrenergic or serotonergic neuronal populations in the pons and/or other brainstem structures. This last monoaminergic neuronal population probably has a gating or inhibiting effect upon the cholinergic and cholinoceptive neuronal populations related to the generation of generalized muscle atonia and REM sleep. In spite of many studies and published reports on REM sleep, as well as on cataplexy and sleep paralysis, we are still far from a complete understanding of the physiological mechanisms producing muscle atonia in REM sleep and of the pathophysiological mechanisms of cataplexy and sleep paralysis--though it is apparent that these mechanisms are closely related.

Animals↗
PubMed1994

Endogenous components of event-related potential appearing during NREM stage 1 and REM sleep in man.

Information processing in the brain during sleep was studied by analyzing the evoked cortical response to auditory stimulations presented in the odd-ball paradigm. Eight subjects were examined in different sleep stages. The subjects could provide the correct behavioral response to the auditory stimulation by pressing a key button in the light part of stage 1 of NREM sleep, just succeeding to the waking state, but none of the subjects could give the correct behavioral response in the other sleep stages. In the deep part of stage 1 of NREM sleep and REM sleep, a cortical potential corresponding to P300, the endogenous component of the event-related potential (ERP) recorded in the waking state, was recorded in 6 of the 8 subjects in spite of the absence of the behavioral response. In stages 2, 3 and 4 of NREM sleep, emergence of this endogenous component of ERP could not be confirmed. The present findings provide electrophysiological evidence indicating that selective information processing corresponding to sensory discrimination of auditory stimuli is actively performed in stage 1 of NREM sleep and REM sleep.

Adult↗
PubMed1994

Muscle sympathetic nerve activity during apneic episodes in patients with obstructive sleep apnea syndrome.

Muscle sympathetic nerve activity (MSNA) was recorded from peroneal nerve in 4 OSAS patients during sleep. During apneic episode, MSNA was enhanced, but it did not increase progressively toward the end of the apneic episode. MSNA remained at a stable level in the later part of an apneic episode. A surge of MSNA took place just preceding or just at the end of an apneic episode and it was followed by a transient marked blood pressure elevation.

Adult↗
PubMed1994

Personal computer-based small PACS for radiotherapy--analog image filing system for radiotherapy.

The purpose of this study is to evaluate the usefulness of a personal computer-based small PACS using analog video images. The analog video recorder, personal computer, and display monitor constitute our system. An analog video recorder is composed of a laser disk recorder for still images and a video cassette recorder for moving images. The acquired video images are managed by a personal computer and database software. The serial communication ports of the personal computer and a video recorder are connected with the reverse cable, and the video recorder is controlled by the personal computer using our program. This system enables filing of multi-modality images including moving images and is used for following up and treatment planning of the patients who received radiotherapy.

Aftercare↗
PubMed1994

Morning bright light therapy for sleep and behavior disorders in elderly patients with dementia.

Fourteen inpatients with dementia showing sleep and behavior disorders (average age = 75 years), and 10 control elderly people (average age = 75 years) were carefully observed for 2 months. Four weeks of morning light therapy markedly improved sleep and behavior disorders in the dementia group. The measurement of sleep time and the serum melatonin values suggests that sleep and behavior disorders in the dementia group are related to decreases in the amplitude of the sleep-wake rhythm and decreases in the levels of melatonin secretions. Morning light therapy significantly increased total and nocturnal sleep time and significantly decreased daytime sleep time. These results indicate that morning bright light is a powerful synchronizer that can normalize disturbed sleep and substantially reduce the frequency of behavior disorders in elderly people with dementia.

Aged↗
PubMed1994

Preoperative detection of local extension of carcinoma of the rectum using magnetic resonance imaging.

BACKGROUND: We evaluated the ability of magnetic resonance imaging (MRI) to define local extension of rectal carcinoma. STUDY DESIGN: Thirty-three patients with rectal carcinoma were preoperatively assessed by MRI. RESULTS: When sagittal or coronal images, or both, were added to transverse images as needed, the sensitivity rate was 84.2 percent and the specificity rate was 92.9 percent. False-positive results when using only transverse images were mainly related to slight extramural spread, to an anterior location in the lower rectum (partial volume effect), and to massive extramural spread of the middle rectal tumors. CONCLUSION: Preoperative MRI was helpful to define tumor extension three-dimensionally.

Aged↗
PubMed1993

Anorectal function after preoperative intraluminal brachytherapy and colonic J pouch-anal anastomosis for rectal carcinoma.

The effects of preoperative intraluminal brachytherapy on bowel function after anoabdominal rectal resection and colonic J pouch-anal anastomosis were studied. The patients included eight not receiving irradiation (group 1), eight who received 30 Gy (group 2) and eight who received 80 Gy (group 3). Stool frequency and the incidence of soiling were significantly greater in group 3 than in the other groups. Anal resting pressure was lower in group 3 during the study period but J pouch distensibility was not reduced. The maximum tolerated volume, threshold volume and squeeze pressure were significantly lower in group 3 than in the other groups in the early postoperative period. These results suggest that high-dose brachytherapy affects the anal sphincters and colonic J pouch. A moderate dose of 30 Gy may be more suitable before restorative anorectal surgery.

Adult↗
PubMed1993

Cortical reactivity in REM sleep with tonic mentalis EMG activity induced by clomipramine: an evaluation by slow vertex response.

Slow vertex response (SVR) to sound stimuli was used as an index to assess whether cortical reactivity in REM sleep with tonic mentalis EMG activity (stage 1-REM) corresponds to that in REM sleep or rather to that in stage 1 of NREM sleep. In 11 young adult subjects 3 night polygraphic records were made after administration of 25 or 50 mg of clomipramine or non-active placebo. Stage 1-REM was observed in the drug night in 8 of the 11 subjects. N1-P2 and P2-N2 amplitudes of SVR were markedly smaller in stage 1-REM than in stage 1, but were virtually of the same height in stage 1-REM and in stage REM. This indicates that cortical reactivity in stage 1-REM closely resembles the counterpart in stage REM. This finding corresponds well with the frequent emergence of vivid dreams in stage 1-REM, indicating that stage 1-REM observed in the present subjects probably represents REM sleep without muscle atonia.

Adult↗