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Biomedical subjects

I Oswald

Publications and source records attributed to I Oswald.

At least 55 records · Page 3Linked to original sources
PubMed1984

Effect of physical fitness and body composition on sleep and sleep-related hormone concentrations.

The study assessed the effect of physical fitness and body composition on sleep and the nighttime secretion of the hormones, human growth hormone (hGH), prolactin, and cortisol. Two groups of 17 subjects, one of fit athletes and the other of unfit nonathletes, were selected so that the groups were matched for weight, height, lean body mass (LBM), and fat levels. Subjects slept in a sleep laboratory for 3 nonconsecutive nights: 1 adaptation night and 2 experimental nights. On 1 experimental night blood samples were collected; on the other, baseline sleep was assessed and the catheter was not inserted. Weight and height were measured and LBM assessed by 24 h urinary creatinine. The effect of physical fitness was tested by a comparison of the two groups; body composition was assessed by correlation analyses. Physical fitness did not have a significant effect on either sleep or hormone levels, although in the latter case the results were marginal. In contrast, body composition was related to both sleep and hGH. Percentage LBM was negatively correlated with slow-wave sleep and positively correlated with hGH levels. These results were significant for all subjects combined and for the fit group, although not the unfit group alone.

Adipose Tissue↗
PubMed1984

Effects of lormetazepam and of flurazepam on sleep.

Nine poor sleepers of mean age 61 years took part in a double-blind, balanced order study in which, during three periods of 3 weeks, each took lormetazepam 1 mg, lormetazepam 2.5 mg, and flurazepam 30 mg. Using electrophysiological measures, sleep was found to increase by 0.75 h with each treatment condition, mainly through more of stage 2 sleep. The treatments reduced the delay to sleep and led to fewer and shorter awakenings, with little difference among the three treatments. Slow-wave sleep was reduced by flurazepam and by lormetazepam 2.5 mg. After flurazepam intake ceased, there was evidence of persisting drug effects for as long as 7 nights. In contrast, when lormetazepam 2.5 mg ceased, there was significant rebound reduction of sleep duration below baseline for up to 3 withdrawal nights, and there was a similar though non-significant trend after lormetazepam 1 mg had ceased. Wakefulness in the final 2 h of nocturnal recording during the third week of drug intake was significantly reduced below baseline by flurazepam, but was little affected by lormetazepam. The differences among the treatment conditions could be attributed to the long-persistence of flurazepam vs the more rapid elimination of lormetazepam.

Aged↗
PubMed1984

Heat production during sleep.

Heat production during sleep was studied by continuous indirect calorimetry with simultaneous electroencephalographic monitoring. Controlling for gross influences on heat production, comparisons of heat production during different sleep stages showed heat production in stage 4 sleep to be significantly lower than in other sleep stages. There appeared to be a gradation in heat production in non-rapid-eye-movement stages of sleep with stage 2 higher and stage 4 lower than stage 3. Heat production in stage 4 was less variable than in any other sleep stage. Both the level and variability of heat production was similar in stage 2 and rapid-eye-movement sleep. Heat production during the night was 9% lower than during resting wakefulness. The average heat production in stage 4 sleep was 14.4% lower than resting wakeful values.

Adult↗
PubMed1983

Circadian variation of lymphocyte subpopulations: a study with monoclonal antibodies.

Use of monoclonal antibodies to identify subpopulations of circulating lymphocytes in healthy adults showed pronounced circadian variations in total T cells, the two major T cell subsets, and HLA-DR+ lymphocytes. When the results for the T cell subsets were expressed as a ratio (helper:suppressor) no significant rhythmic variation was observed. Lymphocytes bearing a surface antigen identified by the HNK-1 antibody (a population containing the natural killer and antibody dependent killer activity) did not show significant rhythmic variation. There was an inverse relation between plasma cortisol concentration and numbers of T and B cells. These observations have therapeutic implications and should be considered in the course of immunological monitoring.

Adult↗
PubMed1983

Interference with human memory by an antibiotic.

Thirty-two volunteers learned a sentence after awakening from early in the first REM period of sleep and recalled it after awakening from the third REM period, under experimental conditions that controlled for state dependency. The tetracycline antibiotic doxycycline (200 mg), taken at bedtime, impaired recall possibly through a putative inhibitory action on brain protein synthesis.

Adult↗
PubMed1983

Trazodone enhances sleep in subjective quality but not in objective duration.

Nine volunteer poor sleepers, of mean age 61 years, took trazodone 150 mg nightly for 3 weeks, preceded by 2 weeks and followed by 1 week of matching blanks, in order to examine the effects of electrophysiologically-recorded and subjectively-rated sleep. The second of the initial weeks of matching blanks served as a baseline week. In the subjective ratings, sleep improved in quality on trazodone, significantly so in the first and second weeks of intake, though with significant rebound insomnia on the second withdrawal night. Trazodone halved the frequency of arousals interrupting sleep, and it reduced the time spent in stage 1 (drowsiness). It increased the duration of slow-wave sleep (stages 3 + 4), with a negative rebound following withdrawal. It reduced the time spent in REM sleep, with a rebound above baseline levels after withdrawal. Trazodone did not change total sleep duration, nor the time required to fall asleep. The effects of trazodone were sustained or became enhanced during the period of intake. They persisted for over 24 h after the last dose, and rebound effects were maximal on the second withdrawal night.

Aged↗
PubMed1982

Benzodiazepine hypnotics remain effective for 24 weeks.

Ninety-seven poor sleepers aged 40-68 years took capsules nightly for 32 weeks and made daily subjective ratings. The benzodiazepine hypnotics lormetazepam 2 mg and nitrazepam 5 mg appeared still to improve sleep after 24 weeks of intake when compared with continuous placebo intake. The sustained effectiveness was most evident in a significant shortening of the time taken to fall asleep in patients receiving lormetazepam. After weeks, sleep latency and the quality of sleep were significantly worse than baseline values. The impairment was maximal on the second night after withdrawal of lormetazepam and on the fourth night after withdrawal of nitrazepam. It is concluded that benzodiazepines remain effective for at least 24 weeks but that a period of disturbed sleep may be expected after withdrawal.

Adult↗
PubMed1982

Human EEG slow-wave sleep increased by a serotonin antagonist.

Serotonin has been held to play a necessary role in EEG slow-wave sleep. A central serotonin antagonist, known as FU 29-245, 200 mg, was taken nightly for 6 nights by 10 volunteers, mean age 59 years. Compared with baseline sleep the drug significantly increased the duration of slow-wave sleep, with a significant rebound decrease below baseline after withdrawal. The drug also caused fewer transitions into stage 1 and less time in stage 1 and less time in stage 2. There were significant tolerance effects by the fifth and sixth nights. No subjective effects were present.

Adult↗
PubMed1982

A comparison of the effects of chlormezanone and nitrazepam on sleep.

1 Twelve volunteers, of mean age 60 years, took part in a double-blind, balanced cross-over study, to compare effects of chlormezanone 400 mg and nitrazepam 5 mg on electrophysiologically-recorded and subjectively-rated sleep. 2 In the first week of administration nitrazepam caused a significant shortening of the time to fall asleep, but following withdrawal subjects took longer to fall asleep than during the baseline period. 3 Both chlormezanone and nitrazepam initially caused increase of sleep duration and less interruption of sleep by wakefulness. By the third week, for chlormezanone this effect was no longer significant, and for nitrazepam there was a significant decline in the effect. There was no statistically significant difference between the two drugs for these measures. 4 The drugs differed little in their effects on the amount of the various sleep stages, except that nitrazepam significantly reduced the duration of slow wave sleep, whereas chlormezanone had no significant effect on slow wave sleep. Both drugs reduced the amount of REM sleep in the first 6 h of sleep but only nitrazepam reduced the percentage of the time spent in REM sleep of the whole night. 5 Subjects' own ratings of sleep quality showed that both of the drugs improved sleep, but following withdrawal it was only after nitrazepam that there was impairment of the quality of sleep. Neither drug affected subjective alertness in the morning.

Adult↗