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Biomedical subjects

C P Pollak

Publications and source records attributed to C P Pollak.

At least 37 records · Page 2Linked to original sources
PubMed1990

Sleep problems in the community elderly as predictors of death and nursing home placement.

In 1984-85, 1855 elderly residents of an urban community responded to a comprehensive baseline interview that included questions regarding an extensive set of sleep characteristics and problems. During the subsequent 3 1/2 years of follow-up, 16.7% of the respondents died and 3.5% were placed in nursing homes. The predictive significance of each sleep characteristic for mortality and for nursing home placement was determined separately for males and females, using Cox proportional hazards models. Selected demographic and psychosocial variables were also entered into the models. Age, problems with activities of daily living (ADL), self-assessed health, income, cognitive impairment, depression and whether respondents were living alone were controlled for statistically. Of the many variables analyzed, in males insomnia was the strongest predictor of both mortality and nursing home placement. For mortality, the relative hazard associated with insomnia exceeded the hazards associated with age, ADL problems, fair-poor health and low income. For nursing home placement, the hazard associated with insomnia exceeded that associated with cognitive impairment. The relationships of insomnia to mortality and nursing home placement were U-shaped, with a worse outcome if insomnia complaints over the preceding 2 weeks were either prominent (numerous or frequent) or absent. For females, insomnia was a borderline predictor of mortality and did not predict nursing home placement at all. Symptoms of the restless legs syndrome predicted mortality for females in some Cox regression models. Reported sleep duration, symptoms of sleep apnea and frequent use of hypnotic drugs did not predict mortality or nursing home placement in either sex.

Aged↗
PubMed1990

Eating and its relationships with subjective alertness and sleep in narcoleptic subjects living without temporal cues.

The sleep and meal patterns of normal subjects appear to be governed by a common timing mechanism. To investigate whether the postulated mechanism may be disordered in narcolepsy, a disorder of sleep timing, we analyzed the sleep, eating, and subjective alertness of six narcoleptic subjects and seven normal controls while they lived in a temporal isolation laboratory. When subjects were free to eat and sleep whenever they chose ("free-running"), the meal patterns and nutrient intakes of the free-running narcoleptic subjects and controls were similar; no evidence of an eating disorder intrinsic to narcolepsy was found. When meals were offered on a 24-h schedule, narcoleptic subjects ate more frequently than did the controls. In two of three narcoleptic subjects whose free-running biological days markedly lengthened, intermeal intervals lengthened proportionately. This was evidence that the timing of sleep (bed-dark) periods and meals was indeed governed by a common mechanism. Meal onsets of narcoleptic subjects were preceded by a 90-min period of decreased napping and, when meals were scheduled, by increased subjective alertness. They were followed by a 150-min period of increased napping and decreased subjective alertness. Postprandial deactivation was not found in controls. The deactivation could not be explained by a post-absorptive effect of food, since the contents of meals that were followed by naps did not differ from those that were not followed by naps. While a preabsorptive effect of meals has not been ruled out, we suggest that postmeal deactivation may be evidence that the mechanism that times sleep periods and meals also modulates the temporal pattern of narcoleptic naps.

Adult↗
PubMed1989

Blood glucose prior to meal request in humans isolated from all temporal cues.

The factors responsible for meal initiation in man are not known. Recently, a small, transient decline in blood glucose was found to precede meals in freely feeding rats (1). To determine whether a similar decline in blood glucose precedes meals in humans, we measured plasma glucose concentration before and after requests for lunch on 4 different days in each of 7 subjects living in a setting that eliminated temporal cues and most or all external prompts for eating. Under these conditions, subjects could request any meal at any time by naming it and specifying its content. Meals were promptly prepared and served. Blood was sampled at randomized intervals averaging 20 minutes. Blood samples from 120 minutes preceding the subject's request for lunch to 90 minutes after the request were analyzed for glucose by the hexokinase method. The mean plasma glucose concentration did not change significantly from about 1 hour before lunch request to 20-30 minutes after the request. A transient decline in glucose similar to that reported in the rat was observed prior to only 1 of the 28 lunches. Given the ease of obtaining food and the absence of the usual temporal and psychosocial cues for eating, the results are not consistent with the hypothesis that meal requests in humans are triggered by a transient decline of plasma glucose concentration. The hypothesis is not disproven, however, since the intersample intervals of about 20 minutes may have failed to detect decreases of blood glucose that were smaller or of shorter duration than those of the rat.

Adult↗
PubMed1987

The effect of desynchronization on meal patterns of humans living in time isolation.

We analyzed the timing of meals in nine subjects who lived for several weeks in a time isolation environment and whose free-running sleep-wake cycles lengthened markedly and lost synchrony with the body temperature rhythm for part of the study. The long sleep-wake periods (SWP) in free-running desynchrony (mean = 34 +/- 3 hours) as compared to free-running synchrony (25 +/- 1 hours) enabled us to compare meal timing in two distinct temporal frameworks and to relate them to the two major oscillators presumed to underlie circadian rhythms in man. We found that when the SWP lengthened in desynchrony, the intermeal interval (IMI) increased significantly. In half the subjects, the increase in IMI was approximately proportional to the increase in the SWP--the IMI "stretched" along with the SWP. Analysis of prelunch and postlunch IMIs indicated that the lengthening of the IMI during desynchrony was comparable in early and later parts of the subjective day. The increase in meal spacing was not due to increased caloric content of meals. The findings support an interpretation of dual regulation of meal timing. Proportional increases in IMI and SWP suggest that the mechanism governing the timing of the sleep-wake cycle also governs meal timing. The less than proportional increase in some cases suggests that an additional, probably metabolic, mechanism tends to limit the intervals between meals.

Adolescent↗
PubMed1987

Meal size and intermeal interval in human subjects in time isolation.

We analyzed the content and number of meals eaten by eight subjects who lived for several weeks in time isolation and whose free-running sleep-wake periods (SWP) lengthened (to an average of more than 33 hours) and were desynchronized from the stable 25 hour rhythm of body temperature. Recently, in an analysis of meal timing, we reported that the long SWPs of free-running desynchrony (FRD) were associated with significantly longer intermeal intervals (IMI) than the shorter SWPs of free-running synchrony (FRS), suggesting that meals and sleep-wake events are timed by the same mechanism. We now report that in both FRS and FRD, subjects ate approximately three meals per SWP and the average size of a meal was similar across conditions. As a result, mean caloric intake decreased by 21 percent per 24 hours and mean satiety ratio increased by 27 percent on the long biological days of FRD. Despite the decrease in caloric intake, body weight did not change significantly in FRD compared to FRS. Decreased food consumption in FRD was not attributable to lowered core body temperature. The similarity of average meal size in the two FR conditions suggested that increased meal size did not drive the longer IMIs of desynchrony, although variability of caloric intake from meal to meal within conditions correlated with postmeal and premeal intervals. The results are interpreted as further support for the concept that in time isolation, the same mechanisms that governs the timing of sleep and waking is important in regulating the timing of meals.

Adolescent↗
PubMed1985

Diurnal variation in mood and performance in a time-isolated environment.

In order to document circadian rhythmicity in various psychological functions under the chronobiologically 'pure' condition of temporal isolation, a battery of mood and performance tests were administered about 6 times per day to a heterogeneous group of 18 subjects (ages 19-81, 5 female). Each subject spent about 5 days in temporal isolation, entrained to a routine equivalent to his/her own habitual sleep/wake cycle. Average time of day functions were obtained for the mood and performance variables, and compared to rectal temperature data subjected to exactly the same statistical analysis. Significant time of day effects were found in the mood variables of alertness, sleepiness, weariness, effort required, happiness and well-being. Times of 'best' mood were different from the time of peak temperature. Moreover, the minima of sleepiness, weariness and effort occurred earlier in the day than the maximum of alertness. Significant time of day effects were also found in the speed with which search and dexterity tasks were completed. Only the dexterity tasks showed a complete parallelism with the temperature rhythm.

Adult↗
PubMed1984

Patterns of daytime sleepiness in narcoleptics and normals: a pupillometric study.

Pupil diameter was measured in light and dark conditions every half hour for 6.5-10 h in 3 normal controls and 3 narcoleptics. Mean pupillary diameter was significantly smaller in the narcoleptic group than in the normal group. Pupil activity was correlated with pupil diameter only in the dark condition in narcoleptics. Pupil diameter varied with a circa 90 min periodicity in the narcoleptics but not in the normal controls. These results indicate firstly, that one-time assessment of pupil size is insufficient; and secondly, that the appearance of these rhythms may be the result of a defect in arousal mechanisms of narcoleptics which usually play an inhibitory role.

Adult↗
PubMed1983

Obstructive sleep apnea and its therapy: clinical and polysomnographic manifestations.

Obstructive sleep apnea syndrome was studied in 32 children, aged 2 to 14 years, in the sleep-wake disorders center at Montefiore Hospital and Medical Center during the years 1977 to 1980. All children underwent all-night polysomnograms; 17 of these children had surgery to relieve airway obstruction and seven had a repeat polysomnographic study 4 to 6 weeks following the surgery. There was a significant improvement in the number of obstructive apneas and in other apnea indices following surgery. There was no significant effect on the durations and the proportions of the various sleep stages, on sleep efficiency, or on the number of awakenings.

Adenoidectomy↗
PubMed1982

Effects of flurazepam on sleep and growth hormone release during sleep in healthy subjects.

We studied the effect of flurazepam, a known suppressor of stages 3 and 4 of sleep, on nocturnal sleep patterns and on growth hormone release immediately following sleep onset in normal young adults. Polysomnography and sampling of growth hormone (every 20 min for 26 h) were performed before and after 2 weeks of nightly flurazepam (30 mg, 8 subjects) or placebo (8 subjects) administration. There were no significant changes in growth hormone release in spite of a significant decrease in stage 4 sleep (69%) and total waking time (46%) and an increase in total sleep time (23%) in the drug group. REM sleep was not changed. These results indicate that the normal GH release following sleep onset continues to occur despite stage 4 suppression by pharmacological means.

Adult↗
PubMed1981

Delayed sleep phase syndrome. A chronobiological disorder with sleep-onset insomnia.

We describe a new syndrome called "delayed sleep phase insomnia." Thirty of 450 patients seen for a primary insomniac complaint had the following characteristics: (1) chronic inability to fall asleep at a desired clock time; (2) when not on a strict schedule, the patients have a normal sleep pattern and after a sleep of normal length awaken spontaneously and feel refreshed; and (3) a long history of unsuccessful attempts to treat the problem. These patients were younger than the general insomniac population and as a group did not have a specific psychiatric disorder. Six patients' histories are described in detail, including the successful nonpharmacological chronotherapy regimen (resetting the patients' biological clock by progressive phase delay). Delayed sleep phase insomnia is proposed to be a disorder of the circadian sleep-wake rhythm in which the "advance" portion of the phase response curve is small.

Adolescent↗
PubMed1981

Sleep apnea and hypoventilation syndrome associated with acquired nonprogressive dysautonomia: clinical and pathological studies in a child.

A 6-year-old girl had subacute onset of hypoventilation and apnea during sleep. Diffuse dysautonomic changes were identified, including dilated, nonreactive pupils, decreased tearing and sweating, and abnormal temperature and cardiovascular control. All-night polysomnographic studies revealed frequent obstructive and central sleep apnea episodes. Her serum contained cytotoxic antineuroblastoma immunoglobulins. She died two years later during sleep. The general pathological examination revealed a ganglioneuroma originating in the sympathetic ganglia. Abnormalities in the brain were confined to the brainstem and consisted of complete loss of neurons with severe fibrillary gliosis in the region of the Edinger-Westphal nuclei as well as loss of neurons with gliosis in the locus ceruleus and in the reticular formation bilaterally.

Antibodies, Neoplasm↗
PubMed1980

Periodic movements in sleep (nocturnal myoclonus): relation to sleep disorders.

Periodic movements in sleep (PMS) are stereotyped, repetitive, nonepileptiform movements of the lower extremities. A total of 409 sleep disorder patients were studied with all-night polysomnogram recording, and 53 (13%) had PMS. Such movements occurred in a wide variety of sleep-wake disorders in addition to insomnia. The prevalence and magnitude of PMS were not statistically greater in patients with insomniac disorders than in those with syndromes of excessive daytime sleepiness or other sleep-wake disorders. The results suggest that although PMS is responsible for disturbed sleep in relatively few patients, chronic sleep-wake disturbance is associated with PMS and may lead to the development of these movements.

Electroencephalography↗
PubMed1980

Impaired nocturnal erections and impotence following transurethral prostatectomy.

A case of impotence with significantly impaired nocturnal penile tumescence (NPT) following transurethral resection of the prostate (TURP) is described. The patient was studied with polysomnographic recording including measurements of NPT for three consecutive nights at nine months after surgery and showed a total absence of full erections. Possible causes of his impotence are discussed. It is concluded that the total clinical picture strongly suggests that the erectile dysfunction was a result of physiologic complications of the surgery. Methodologic problems in past work are discussed, and the need for detailed diagnostic studies is stressed. The sleep studies that should be a part of this comprehensive evaluation are described.

Erectile Dysfunction↗
PubMed1980

Obstructive sleep apnea and death associated with surgical correction of velopharyngeal incompetence.

We have observed three children who developed obstructive sleep apnea immediately following construction of pharyngeal flaps designed to improve the speech of these patients with velopharyngeal incompetence. Postoperatively the patients were noted to have repeated episodes during sleep of strong respiratory efforts without airflow. Sleep apnea can be debilitating and lethal, and should be looked for following surgery of the upper airway. Respiratory depressants should be avoided. Airway intubation, revision of the surgery, or tracheostomy may be necessary.

Child↗