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Biomedical subjects

Hiroshi Yamadera

Publications and source records attributed to Hiroshi Yamadera.

11 recordsLinked to original sources
PubMed2003

Study of nocturnal sleep and the carryover effects of triazolam and brotizolam using neurophysiological and subjective methods.

In the present study, the effects of short-acting benzodiazepines on nocturnal sleep and the carryover effects of these drugs were studied. The study involved 10 young, healthy male subjects who had given their written informed consent to participate. Either a placebo (PLA), 0.125 mg triazolam (TRZ), 0.25 mg TRZ or 0.25 mg brotizolam (BRZ) was administered to the subjects in a double-blind crossover design by randomized allocation with a single oral administration at 23.00 h. A polysomnography (PSG) was recorded for each subject from 23.00 to 07.00 h the following day. Then, the Stanford Sleepiness Scale (SSS) and Kwansei Gakuin Sleepiness Scale (KSS) were checked between 07.55 and 08.00 h, and the sleep latency test (SLT) was performed between 08.00 and 08.20 h. Event-related potentials (ERPs) were then recorded with an oddball paradigm; the reaction time (RT) was measured simultaneously. According to the PSG, treatment with 0.25 mg TRZ resulted in a statistically significant increase in the percentage of stage 2 sleep (p < 0.05) and a reduction in the percentage of rapid eye movement sleep (p < 0.05) compared with PLA. None of the drugs had any effect on the percentage of slow-wave sleep compared with PLA. With regard to carryover effects, although none of the drugs had any effect on SSS, KSS, RT or ERPs, BRZ did cause a statistically significant decrease in sleep latency (p < 0.05) compared with PLA. TRZ (0.125 and 0.25 mg) and 0.25 mg BRZ exerted different effects on SLT. We suggest that these different effects are attributable to differences in the half-life of these hypnotics.

Adult↗
PubMed2003

Double blind study of melatonin effects on the sleep-wake rhythm, cognitive and non-cognitive functions in Alzheimer type dementia.

Previously, we reported that morning bright light therapy improved sleep time and cognitive function in Alzheimer type of dementia. We conducted a double blind study to examine the effects of melatonin on the sleep-wake rhythm, cognitive and non-cognitive functions in Alzheimer type of dementia. The subjects were 9 persons given a placebo (PLA), and 11 given melatonin ( 3 mg)(MLT). The mean age was 79.2+/-6.4 (17 females and 3 males). The drugs were given at 20: 30 each day for 4 weeks. We checked sleep time and activity by Actigraph through one week before and the 4th week after drug administration. Cognitive and non-cognitive functions were evaluated with the clinical dementia rating scale (CDR), and Mini Mental State Examination (MMSE), and the Alzheimer's Disease Assessment Scale (ADAS). We successfully recorded Actigraph data from 18 patients (PLA8, MLT10). The mean sleep time change ratio and SD of the administration of PLA in the night was-0.2+/-13.7%, and MLT was 33.2+/-37.6%. The mean activity counts and SD of the administration of PLA in the night was 29.8+/-77.0%; in MLT it was-44.9+/-21.9%. Melatonin significantly prolonged the sleep time (p=0.017) and decreased activity (p=0.014) in the night (21: 00-6: 00) in the MLT group, although no significant difference in sleep time or activity in the daytime (6: 00-21: 00) was recognized between the two groups. In comparison with ADAS cognition score changes, the mean change and SD in the PLA was 0.3+/-3.7; in MLT it was-4.3+/-3.6 points. In comparison with ADAS non-cognition score, the mean change and SD in the PLA group was-0.8+/-1.0, in the MLT group it was-4.1+/-2.2 points. There were also significant differences between the PLA and the MLT groups in the comparison with the score improvement of ADAS cognition (p=0.017) and non-cognition (p=0.002), otherwise there was no significant difference in improvement of MMSE between both groups. Melatonin administration had effect to improve sleep time and night activity, but no significant effect to improve daytime naps and activity. Although melatonin administration might has less strong effect on circadian rhythm than morning bright light therapy we previously reported, cognitive and non-cognitive functions were improved. Melatonin seemed to be useful for care of the Alzheimer type of dementia patients.

Aged↗
PubMed2002

The study of polysomnography and sleepiness the morning after administration of triazolam and brotizolam.

Using polysomnography, sleep effect was studied, then the sleep latency test (SLT), Stanford Sleepiness Scale (SSS), and Kwansei Gakuin Sleepiness Scale (KSS) were studied the next morning after administration of either an inactive placebo (PL), 0.125 mg triazolam (TL), 0.25 mg triazolam (TH), or 0.25 mg brotizolam (BR). Ten healthy male volunteers were used for the double-blind crossover design. TL increased the percentage of stage 2 sleep significantly compared with PL, whereas TH decreased the number of stage shifts significantly. TH and BR increased the percentage of stage 2 sleep significantly and decreased the percentage of rapid eye movement sleep significantly. Although no drug had any effect on SSS and KSS, BR decreased the sleep latency in SLT significantly.

Adult↗
PubMed2002

[Chronobiological research on antidepressant drugs: the effect of the antidepressant drugs, trazodone and imipramine on the circadian rhythm using electroencephalography in healthy volunteers].

The effects of the antidepressant drugs trazodone and imipramine on the circadian rhythm were studied by means of the sleep propensity test (SPT; sleep latency was examined by 35-minute EEG records at 09:00, 11:00, 13:00, 15:00, 17:00). The subjects were 11 healthy male volunteers (mean age, 23.6 years old). The drugs were administered 4 times a day with single blind trials using an inactive placebo as a control. The dosages of the drugs were trazodone 50-100 mg/day and imipramine 20-40 mg/day. We discussed the circadian rhythm referring to previous polysomnograhy (PSG) studies using the same drugs and dosages with most of the same subjects. As a result, the mean sleep latency of SPT was the shortest at 09:00 (p<0.1) with a placebo, at 11:00 (p<0.05) with trazodone and at 13: 00 (not significantly) with imipramine administration. These results suggested that neither drug affected sleepiness. They affected the circadian rhythm during the daytime (=the day rhythm). They delayed the day rhythm. Delay of the day rhythm was due to trazodone and have been caused by not only trazodon administration itself, but also by the increase of slow-wave sleep obtained in the previous night's PSG study. And the day-rhythm delay was due to imipramine and might have been caused by not only imipramine administration itself, but also by the decrease in the percentage of slow-wave sleep and REM sleep, and an increase in REM latency obtained in the previous night's PSG study. Therefore, we concluded that neither drug affected the tendency toward sleepiness, but did affect the day rhythm in healthy subjects.

Adult↗
PubMed2002

Effects of trazodone and imipramine on the biological rhythm: an analysis of sleep EEG and body core temperature.

Depression commonly involves abnormalities of the sleep-wake rhythm, the temperature rhythm, and other biological rhythms. The changes of these biological rhythms are caused in remission by medications. However, it has yet to be clarified whether the biological rhythms are changed as a result of recovery from depression or from the direct pharmacological effects of the antidepressants. Therefore, we have undertaken a study on the direct effects of the antidepressants trazodone and imipramine on the biological rhythms of healthy volunteers. The study involved 12 healthy male volunteers (ages 21 approximately 28 years, mean age 23.9+/-1.7 years) who had given written informed consent. Placebo, trazodone, and imipramine were each administered in a single blind manner four times a day, during the three-day study period. The total daily dosage of trazodone was 100 mg (50 mg in one subject), and of imipramine 40 mg (20 mg in one subject). Subjects were submitted to polysomnography (PSG) and body core temperature (rectal temperature) measurements during the study period. We compared the data concerning the antidepressants to those of the placebo. The results show that, with regard to the sleep rhythm, trazodone significantly increased slow wave sleep (SWS), but no changes were observed in REM (rapid eye movement) sleep. Imipramine significantly decreased REM sleep and prolonged the REM cycle. With regard to the temperature rhythm, trazodone showed a tendency to advance the appearance time of the minimal temperature. Imipramine significantly lowered the maximal temperature and decreased the difference between the maximal and the minimal temperature, but no changes in the phases were observed. Neither antidepressant had any effect on the temperature cycle. Trazodone and imipramine showed different effects on PSG. Furthermore, they had different effects on the temperature rhythm. The changes of the sleep-wake rhythm were greater than those of the temperature rhythm. Although the two antidepressants had different mechanisms of action, it is worthy of note that both directly influenced the biological rhythms of healthy volunteers.

Adult↗
PubMed2002

[The efficacy of donepezil in Alzheimer's disease].

Several studies have reported the efficacy of donepezil (a cholinesterase inhibitor) in patients with Alzheimer's Disease, not only for memory disturbances but also for psychotic and behavioral disturbances. We have experienced one such case that was a 74-year-old female patient with Alzheimer's Disease. Donepezil remarkably improved, for the most part, these symptoms in this case. The scale of Mini-Mental State Examination (MMSE) was improved from 21/30 to 26/30, and the Alzheimer's Disease Assessment Scale (ADAS) was improved from 21.7/70 to 16.3/70. It took about 8 weeks of treatment with donepezil to achieve these results, although some adverse effects associated with the use of donepezil were found in this case. It became difficult for the nursing staff to give care because of hyperactivity and self-assertion.However, the relationship between donepezil and these behavioral disturbances was not clear.This case indicates that donepezil may exacerbate symptoms in Alzheimer's Disease patients who have psychotic and behavioral problems. From a clinical point of view, we concluded that donepezil is therapeutically efficacious for Alzheimer's Disease sufferers, but that some problems still exist.

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