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Biomedical subjects

I Karacan

Publications and source records attributed to I Karacan.

At least 55 records · Page 3Linked to original sources
PubMed1983

Daytime sleepiness as a criterion in hypnotic medication trials: comparison of triazolam and flurazepam.

Sleep laboratory hypnotic medication trials typically determine efficacy by examining changes in polysomnographically recorded sleep. We introduce the use of daytime sleepiness, as assessed by the Multiple Sleep Latency Test (MSLT), as a criterion for daytime functioning in such trials. Two benzodiazepine hypnotics, triazolam (0.5 mg) and flurazepam (30 mg), with short and long half-lives respectively, were compared in a multicentered, double-blind crossover study. Results indicated these medications had virtually indistinguishable nocturnal effects, but differed dramatically during the day. Flurazepam decreased sleep latency on the MSLT, whereas triazolam did not. These results could indicate that daytime sleepiness is a concomitant effect of flurazepam.

Adult↗
PubMed1983

Effects of brotizolam, flurazepam and placebo upon nocturnal auditory arousal thresholds.

Auditory awakening thresholds (AAT) and the back-to-sleep latency (BSL) after nocturnal awakenings from Stage 2 sleep were studied in normal male subjects after placebo, brotizolam (0.25, 0.375 and 0.50 mg) and flurazepam (30 mg). AAT (dB) was measured in five trials spaced across the night in a 'double awakening' procedure with the second awakening in each trial made from Stage 2 sleep. Each drug condition was associated with elevated mean AAT across the five trials in comparison with placebo. In a trial-by-trial analysis only 0.50 mg brotizolam and 30 mg flurazepam were consistently higher in the first three trials compared with placebo. All active drug conditions decreased the mean BSL across all trials in comparison with placebo, but only 30 mg flurazepam and 0.50 mg brotizolam consistently shortened BSL in the first three trials. Brotizolam (0.50 mg) and 30 mg flurazepam are similar in their effects. The subjective improvement reported in insomniac subjects following hypnotic administration may be related to elevation in arousal thresholds and a quick return to sleep after nocturnal sleep disruption.

Acoustic Stimulation↗
PubMed1983

Disturbances of the sleep-waking cycle in patients with vascular brain stem lesions.

Continuous polygraphic recordings of six patients with vascular brain stem lesions were evaluated to investigate the relationship between 1) the localization or extent of the lesions and the alteration of the sleep-waking cycle, and 2) the evolution of the clinical condition and the sleep-waking cycle. Absent REM sleep and severely disorganized NREM sleep were associated with extensive pontine lesions involving the pontine tegmentum. In "locked-in" syndrome, the neural mechanisms responsible for both REM and NREM sleep continued to function, but the sleep-waking cycle was disturbed and marked by sleep-onset REM periods. Lesions in the lower brain stem resulted in absent slow-wave sleep and sleep-onset REM, suggesting that vascular lesions may involve the neural mechanisms responsible for slow-wave sleep. In general, the acute stage of illness was marked by increased awakenings and time spent awake, absent REM sleep, and little or no slow-wave sleep. These results indicate that continuous polygraphic recordings can reveal severe abnormalities due to vascular lesions of the brain stem whereas the waking EEG can only detect mild abnormalities. Improvement in the organization of the sleep-waking cycle in successive polygraphic examinations is likely to be followed by an improvement of the clinical condition. Continuous polygraphic recording is thus a valuable prognostic indicator for vascular brain stem lesions.

Aged↗
PubMed1983

Sleep disorders in the elderly.

Sleep disorders are difficult to distinguish from changes in sleep typically occurring after age 60. Sleep laboratory evaluation is needed to differentiate normal sleep alterations from the similar but more severe symptoms of depression or organic brain syndrome, and to detect sleep apnea, the most common sleep disorder found in geriatric patients. This disorder may be fatal, especially if a hypnotic drug is prescribed. Since biologic rhythms are easily disturbed in the elderly, education about sleep habits may be the most helpful therapy.

Adult↗
PubMed1982

Sleep spindles: pharmacological effects in humans.

In the present paper we summarize the effects of a variety of drugs on sleep spindle activity in humans. The data are derived from 16 studies conducted in our laboratories during the past several years. The Sleep Analyzing Hybrid Computer was utilized to score each record for sleep stage and spindle activity. To the best of our knowledge, this collection of data is the largest currently available on the relationship between drug administration and standardized sleep spindle parameters in normal human subjects. Ten of the studies are dose-response evaluations. We consider this design a powerful and useful approach for basic sleep pharmacology research. Marked spindle enhancement was produced by flurazepam. WE-941 (a new benzodiazepine hypnotic), methaqualone, and secobarbital. Smaller differences were found for atropine, scopolamine, and caffeine. The results are discussed with respect to drug-class differences, sleep induction properties, the current literature, and the benzodiazepine hypothesis. Some of our future research plans with respect to spindle pharmacology also are presented.

Atropine↗
PubMed1982

Cerebral blood flow during paroxysmal EEG activation induced by sleep in patients with complex partial seizures.

Cerebral blood flow (CBF) measurements were combined with sleep polysomnography in nine patients with complex partial seizures. Two methods were used: the 133Xe method for measuring regional (rCBF) and the stable xenon CT method for local (LCBF). Compared to nonepileptic subjects, who show diffuse CBF decreases during stages I-II, non-REM sleep onset, patients with complex partial seizures show statistically significant increases in CBF which are maximal in regions where the EEG focus is localized and are predominantly seen in one temporal region but are also propagated to other cerebral areas. Both CBF methods gave comparable results, but greater statistical significance was achieved by stable xenon CT methodology. CBF increases are more diffuse than predicted by EEG paroxysmal activity recorded from scalp electrodes. An advantage of the 133Xe inhalation method was achievement of reliable data despite movement of the head. This was attributed to the use of a helmet which maintained the probes approximated to the scalp. Disadvantages were poor resolution (7 cm3) and two-dimensional information. The advantage of stable xenon CT method is excellent resolution (80 mm3) in three dimensions, but a disadvantage is that movement of the head in patients with seizure disorders may limit satisfactory measurements.

Adult↗
PubMed1981

Dose-related effects of flurazepam on human sleep-walking patterns.

Two consecutive nights of flurazepam at each of 15, 26, and 45 mg were compared to placebo in a Latin-square double-blind crossover design using 24 healthy young-adult males. Flurazepam had significant hypnotic effects on objective and subjective measures of efficacy: shorter sleep latency, longer sleep time, and fewer awakenings. It also induced morning sedation along with decrements in cognitive performance. Flurazepam had dose-related impacts on both human and computer-scored EEG-EOG parameters: less stages 3 + 4 and decreased EEG delta, less stage 1 REM and decreased REM density, more stage 2 and increased EEG spindling. Also, EEG alpha and movement artifact were decreased and EEG beta was increased. Only a few of the EEG-EOG variables and none of the subjective indices had cumulative changes on the two drug nights. Stage shifting was unaffected at the two lower doses on the first night but decreased at all three dose levels on the second night; percent stages 3 + 4 was unaffected on the first night but decreased at all dose levels on the second night. The rate of delta waveform activity was also diminished by a greater amount on the second night. This study conclusively established that flurazepam affects the EEG-EOG architecture of sleep on each of the first two nights of administration.

Adult↗
PubMed1981

Differentiating psychological characteristics of patients with sleep apnea and narcolepsy.

Fifty male subjects were group-matched for age and socioeconomic status. Twenty of the subjects were diagnosed as having sleep apnea and 20 were diagnosed as having narcolepsy on the basis of sleep studies. The remaining 10 subjects served as normal controls. Differences among the groups were evaluated on the bases of two psychological instruments designed to assess personality characteristics and mood states. The findings suggest that narcoleptics and apneics both present discriminatively different psychological profiles than do normals. Moreover, personality characteristics of these two groups are distinguishable from one another. Apneics tend to be individuals with hypochondriacal and hysterical characteristics, whereas narcoleptics are more easily characterized by anxiety and social introversion. Both severity of psychological disturbance (mean Minnesota Multiphasic Personality Inventory elevations) and personality pattern (two-point codes) distinguish the groups. Key Words: Sleep apnea-Narcolepsy-Psychological profiles.

Affect↗
PubMed1981

Dose-related effects of phenobarbitone on human sleep-waking patterns.

1 Twenty-four healthy male subjects had two consecutive drug nights at 2-week intervals using placebo and 80, 140 and 240 mg doses of phenobarbitone in a double-blind cross-over design. 2 Phenobarbitone produced significant dose-related decreases in sleep latency and number of awakenings, along with increased total sleep time. 3 Both subjective and objective measures of sleep indicated the presence of cumulative (first v second night) effects of phenobarbitone, especially decreases in the number of awakenings and in delta waveform activity. 4 Measures of REM sleep were highly sensitive to phenobarbitone. The high dose decreased REM density to 30% of baseline on the first night and to 18% on the second night. 5 EEG alpha activity was decreased, beta activity was increased and sigma spindle activity was unaffected by phenobarbitone during sleep. 6 Subjects experienced some impairment of cognitive performance along with residual sedation the following morning.

Adult↗
PubMed1981

Effects of disulfiram on the sleep of chronic alcoholics.

Thirty male alcoholic inpatients received in a random double-blind design placebo (P) or disulfiram 250 mg. (D) at bedtime in order to evaluate the effects of the latter on EEG-EOG sleep patterns. Subjects (S's) had no major medical illness and required no medication for 3 weeks prior to the study. There were 13 disulfiram S's and 17 placebo S's. The total REM time decreased significantly (p less than 0.05) in the D group. Total number of REM episodes decreased and latency to stage 1 REM increased in the disulfiram group. These results are characteristic of sleep patterns induced by the administration of catecholaminergics and opposite to those induced by catecholamine inhibiting agents.

Adult↗
PubMed1981

Disulfiram and nocturnal penile tumescence in the chronic alcoholic.

Thirty male sober alcoholic inpatients received placebo or disulfiram in a random double-blind design in order to evaluate the effects of disulfiram on nocturnal penile tumescence. The amount and frequency of full erections were decreased in the cohort receiving disulfiram. Implications of these results for the role of norepinephrine in penile tumescence are discussed.

Adult↗
PubMed1980

Normal human sleep: regional cerebral hemodynamics.

Measurements of regional cerebral blood flow (rCBF) by the xenon 133 inhalation method along with polygraph recordings were made serially during relaxed wakefulness and different stages of nocturnal sleep in 18 right-handed normal volunteers. During stage I-II sleep the fast flow (Fg) values declined significantly, more in the brainstem-cerebellar (BSC) regions than in hemispheric regions. During stage III-IV sleep, Fg further declined diffusely in both hemispheric (-28%) and BSC (-29%) regions. During awakening from stage IV sleep to alpha-frequency wakefulness, BSC flow values increased more than hemispheric flow values. During REM sleep, regional Fg values increased diffusely in both hemispheric (+41%) and BSC (+47%) regions compared with wakefulness. There was a significant inverse correlation between the increase in end-tidal partial pressure for carbon dioxide and the reduction in bihemispheric Fg during sleep. Cerebral vasomotor responsiveness to carbon dioxide is decreased during both REM and non-REM sleep.

Adult↗
PubMed1980

Sleep apnea, narcolepsy, and dreaming: regional cerebral hemodynamics.

Regional cerebral flow after inhalation of xenon 133 as well as polysomnography were recorded during daytime sleep and the awake state in patients with narcolepsy and sleep apnea. Brainstem-cerebellar (BSC) gray matter blood flow (Fg) values in the awake state were reduced below normal (p less than 0.05) in both narcolepsy and sleep apnea; in sleep apnea, bihemispheric Fg values were also reduced in the awake state. After sleep onset, Fg paradoxically increased in narcolepsy but decreased further in sleep apnea. Maximal regional Fg changes occurred in BSC regions in both groups of patients. Oral administration of methylphenidate hydrochloride (Ritalin) increased resting Fg values in awake narcoleptics, particularly in BSC regions, but attentuated Fg increases during sleep onset. Regional Fg values during visual dreaming or hypnagogic hallucinations in narcoleptics were maximally increased in right parietooccipital regions. In narcoleptics, impaired control of sleep-wake and REM mechanisms is attentuated by methylphenidate. In patients with sleep apnea, brainstem functional activity is low in the awake state but becomes critically reduced during sleep, culminating in apnea-stimulated arousal followed by repetitive cycles as sleep recurs.

Adult↗
PubMed1980

Sexual attitudes of psychogenic and organic impotence.

Thirty organically impotent men were contrasted with 21 psychogenically impotent men and 17 normal controls. Distinctions among sexual attitudes, sexual behaviors, and sexual interests were evaluated on the Sex Form. Results suggest that impotent men can be reliably distinguished from non-impotent men on the basis of their use of activity rather than fantasy in coping with life's problems and their interest in receiving treatment for their condition. Separate comparisons between the control group and the two impotent groups further suggest that both can be reliably distinguished from normals. It is more difficult, however, to distinguish between organically and psychogenically impotent men on the basis of sexual interests, attitudes, and behavior. The findings suggest, however, that impotent men generally and psychogenically impotent men in particular tend to be individuals who have relatively low sexual drive, diminished sexual knowledge, and who are prone to active ways of coping with stress. The results are discussed in light of previous findings.

Adult↗
PubMed1980

Diagnosis of erectile impotence in diabetes mellitus. An objective and specific method.

Objective procedures for both the differential and specific diagnosis of erectile impotence were applied in a study of 13 diabetic men. Monitoring of nocturnal penile tumescence provided evidence of patients' erectile capacity and allowed differential diagnosis of organogenic impotence. Follow-up evaluations of penile blood pressure, bulbocavernosus reflex response latency, and plasma concentrations of testosterone and prolactin allowed localization of probable organic deficits. Bulbocavernosus function was compromised in nine patients, and penile systolic blood pressure was abnormally low in five. Hormone levels were typically within the normal range. These procedures are recommended for comprehensive assessment of impotent diabetic persons in both clinical and research settings.

Adult↗