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Biomedical subjects

O Tzischinsky

Publications and source records attributed to O Tzischinsky.

13 recordsLinked to original sources

Melatonin possesses time-dependent hypnotic effects.

The present study investigated the hypnotic effects of 5 mg melatonin in comparison with placebo when administered at 1200, 1700, 1900 and 2100 hours. Eighteen young adults were studied with the 7/13 ultrashort sleep-wake paradigm after an overnight sleep deprivation. Melatonin was administered according to a double-blind Latin square design. After each administration, melatonin significantly increased sleep propensity, the spectral power in the theta, delta and spindles bands, and subjective sleepiness. It significantly decreased the power in the alpha and beta bands and oral temperature. The latency to maximum effect varied linearly from 3 hours 40 minutes at 1200 hours to 1 hour at 2100 hours. These findings indicate that melatonin possesses a time-dependent hypnotic effect and suggest that endogenous melatonin may participate in sleep-wake regulation.

Adult

Actigraphic home-monitoring of the sleep patterns of in vitro fertilization children and their matched controls.

The sleep patterns of 35 in vitro fertilization (IVF) children aged 19 to 57 months and their matched controls were evaluated by actigraphic home-monitoring for three consecutive nights. Actigraphic data were analysed by an automated scoring procedure developed in the authors' laboratory. There were no significant differences in activity levels between IVF multiple-birth subjects and their matched controls or between IVF singletons and their matched controls. In contrast, multiple-birth subjects had higher activity levels during sleep and lower sleep efficiency than singletons in both IVF and control groups. Sleep measures showed night-to-night stability in all groups.

Age Factors

The association between the nocturnal sleep gate and nocturnal onset of urinary 6-sulfatoxymelatonin.

The present study investigated the relationship between the time of nocturnal onset of urinary 6-sulfatoxymelatonin (aMT6s) secretion, and the timing of the steepest increase in nocturnal sleepiness ("sleep gate"), as determined by an ultrashort sleep-wake cycle test (7 min sleep, 13 min wake). Twenty-nine men (mean age 23.8 +/- 2.7 years) participated. The ultrashort sleep-wake paradigm started at 0700 hr after a night of sleep deprivation and continued for 24 hr until 0700 hr the next day. Electrophysiological recordings were carried out during the 7-min sleep trials, which were then scored conventionally for sleep stages. Urinary aMT6s was measured every 2 hr. The results showed that the timing of the sleep gate was significantly correlated with the onset of aMT6s secretion. These results are discussed in light of the possible role of melatonin in sleep-wake regulation.

Adult

Sleep patterns of children sleeping in residential care, in kibbutz dormitories and at home--a comparative study.

The present study compares sleep patterns of two groups of children sleeping away from their families, in residential care (n = 31, age 3.7 +/- 1.7 years) and kibbutz (n = 29, age 3.7 +/- 1.8 years) dormitories, with age-matched children sleeping at home (n = 21, age 3.7 +/- 1.8 years). Sleep was monitored by wrist-worn actigraphs for three consecutive nights and assessed by sleep questionnaires, which were completed by parents of the kibbutz children and caretakers at residential care. Children in the residential care settled to sleep significantly earlier and slept longer than those children living in a kibbutz or at home. The longest period of uninterrupted sleep was more extended for children sleeping at home, compared to those sleeping in communal dormitories. Correlation analysis between various assessments of sleep and waking behaviors revealed a different pattern for kibbutz and residential care children. For the kibbutz children, there were significant correlations between difficulties falling asleep and various attributes of daytime tiredness. Conversely, in the residential care, difficulties falling asleep were significantly and positively correlated with parameters associated with daytime alertness. This pattern of correlations and the actigraphic data indicate that difficulties in falling asleep for children in residential care are probably a consequence of being put to bed too early and according to a rigid schedule, and not the result of emotional factors.

Child Behavior

The importance of timing in melatonin administration in a blind man.

An 18-year-old blind man suffered from chronic sleep disturbances associated with daytime fatigue and excessive daytime somnolence. After two unsuccessful treatment regimens with 5 mg and 10 mg melatonin administered at bedtime (2200-2230), a third regimen of 5 mg melatonin administered at 2000 for 3 weeks resulted in a successful resolution of his sleep disturbances. We suggest that the efficacy of melatonin in ameliorating sleep disturbances because of alterations in circadian rhythmicity may be dependent on the time of administration.

Adolescent

Actigraphic measurements of sleep in rheumatoid arthritis: comparison of patients with low back pain and healthy controls.

Actigraphic recordings during sleep were carried out in patients with rheumatoid arthritis (RA), in patients with chronic low back pain, and in healthy controls for 4 consecutive nights. All derived measures of sleep quality showed that the sleep of patients with RA was significantly poorer than controls, while patients with chronic low back pain had sleep quality not significantly different from either group. Polysomnographically defined periodic movements in sleep were significantly related to sleep efficiency in patients with RA. Clinical status in these patients was significantly related to several actigraphic sleep measures.

Arthritis, Rheumatoid

Sleep-wake cycles in multi-infarct dementia and dementia of the Alzheimer type.

We monitored by actigraphs minute-by-minute activity of 10 patients with multi-infarct dementia (MID), 15 patients with dementia of the Alzheimer type (DAT), and 11 control volunteers for eight consecutive 24-hour periods to assess sleep-wake cycles and sleep quality. MID patients had disrupted sleep-wake cycles associated with decreased sleep quality. In contrast, ambulatory DAT patients maintained a relatively normal sleep-wake cycle that did not differ significantly from controls. There was no correlation between the severity of intellectual deterioration and the degree of sleep-wake cycle disintegration in either group of dementia patients.

Aged

Circadian rhythms in 6-sulphatoxymelatonin and nocturnal sleep in blind children.

This article describes the relationship between melatonin secretion and sleep quality and subjective complaints about sleep in totally blind children. Eleven boarding-school children (mean age 15.2 years) participated. The major urinary melatonin metabolite 6-sulphatoxymelatonin (aMT6s) was measured five times a day for 48 h. Sleep-wake cycles were recorded by continuous actigraphic recordings during the same time period. Results showed that delayed secretory peaks in aMT6s were significantly associated with disturbed nocturnal sleep and with complaints about morning fatigue.

Adolescent

Agonist-like effects of the benzodiazepine receptor antagonist RO 15-1788.

The present study investigated the effects of the benzodiazepine receptor antagonist RO 15-1788 on the ability to resist sleep after 1 night of sleep deprivation. Repeated administrations of RO 15-1788 to 6 subjects significantly decreased their ability to resist sleep in comparison with repeated administration of 100 mg of vitamin C, and with a nontreatment condition. Most of the hypnotic effect occurred 80-100 min after drug ingestion. RO 15-1788 also significantly enhanced sleep stage 2 spindles activity. These results demonstrate that at certain dosages RO 15-1788 has agonist-like effects.

Adult

Cognitive asymmetry and dreaming: lack of relationship.

The present study investigated the relationship between cognitive laterality and dream recall, dream characteristics, and eye movement density in rapid eye movement (REM) sleep. Fifty-two right-handed males, age 20-30 years, were tested on a six-test battery of which three tests measure right hemisphere function and three tests measure left hemisphere function. Based on their performance, 14 subjects were selected for a sleep laboratory study. Each spent 3 experimental nights in the laboratory during which they were awakened from REM sleep for dream reports. Dream reports were scored for bizarreness, emotions, visual elements, and overall "dreamlike" versus "thoughtlike" character. Subjects were awakened from 123 REM periods, of which 96 yielded positive dream reports (78.04%). Neither the rate of recall nor the four evaluation scores were correlated with the laterality scores that were constructed from the six-test battery. Eye movement density during REM sleep was significantly positively correlated with the total performance of the two hemispheres. These results do not support the alleged lateralization of dreaming. In agreement with recent reports in the literature, it is concluded that dreaming cannot be seen as a "right hemisphere" function.

Adult

Cognitive asymmetries after waking from REM and NONREM sleep: effects of delayed testing and handedness.

The present paper describes two experiments designed to investigate cognitive asymmetry after awakening from REM and NONREM sleep as a function of time after the awakening and handedness. Two groups of 9 right-handed male subjects each participated in the first experiment. Subjects were awakened from REM and NONREM sleep and after 35 min (Group 1), or 75 min (Group 2), tested on a 6-test battery designed to measure cognitive asymmetry. In contrast to our previous findings in subjects tested within 1-2 min after the awakening who showed a significant sleep-stage dependent shift in cognitive asymmetry, the present results did not show significant differences in performance between the two awakening conditions for any of the groups. Two groups of 12 male and 12 female left-handed subjects participated in the second experiment. All subjects were tested within 1-2 min after the awakenings from REM and NONREM sleep on the same 6-test battery as in experiment 1. Also in contrast to our previous findings in right handers, left-handers did not show any consistent shifts in cognitive asymmetry after the awakenings.

Adult

Sleep-wake cycle in shift workers on a "clockwise" and "counter-clockwise" rotation system.

The present study investigated the effects of a 5-day rotating work schedule in the advance, or "counter-clockwise", vs. delay, or "clockwise" direction, on subjective and objective measures of sleep-wake cycles. Twenty-two workers (mean age 27.5 +/- 4.6 years) were studied in the counter-clockwise direction, and 11 workers (mean age 29.83 +/- 5.93) were studied in the clockwise direction. Each worker was studied for a complete rotation cycle (20 days). Sleep-wake cycles were measured by wrist-worn actigraphs in 1-min bins. The clockwise direction was associated with significantly earlier sleep times during the night shift, and with a better synchronization of workers' sleep-wake cycles during night and evening shifts. The present results provide support to the claim that rotating shiftworkers can better adapt to clockwise than counter-clockwise rotations.

Adaptation, Physiological