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Biomedical subjects

I Karacan

Publications and source records attributed to I Karacan.

At least 73 records · Page 4Linked to original sources
PubMed1980

Sleep EEG in depression.

Depression is a common psychiatric disorder with sleep disturbance as a concomitant symptom. This paper selectively reviews the earlier, more global research and more recent studies with improved methodologies. Research has shown that EEG sleep changes (in particular, REM) can be used as an aid in differential diagnosis of depression and possibly as a way of treatment. It is speculated that an ultradian cycle disruption involving REM sleep mechanisms is related to primary depression.

Antidepressive Agents, Tricyclic↗
PubMed1979

Erectile impotence treated with an implantable, inflatable prosthesis. Five years of clinical experience.

Erectile impotence can now be treated with a device that mimics a natural erection. Between 1973 and 1977, we implanted an inflatable prosthesis in 245 men (235 with organic impotence and ten with psychogenic impotence). Of these, 234 are able to use the device to their satisfaction; no failures have occurred in the 152 cases treated in 1976 and 1977. The success of this treatment rests in part on the careful selection of patients by a team--a urologist, a sleep researcher, a psychologist, and a psychiatrist--each evaluating the patient independently. Our experience suggest that erectile impotence may be more common than generally believed and that impotence from organic causes may account for a greater percentage of cases than formerly thought.

Adult↗
PubMed1979

Narcolepsy: regional cerebral blood flow during sleep and wakefulness.

Serial measurements of regional cerebral blood flow were made by the 135Xe inhalation method during the early stages of sleep and wakefulness in eight normal volunteers and 12 patients with narcolepsy. Electroencephalogram, electro-oculogram, and submental electromyogram were recorded simultaneously. In normals, mean hemispheric gray matter blood flow (Fg) during stages I and II sleep was significantly less (-9.2 percent) than waking values (84.3 +/- 13 ml per 100 gm brain per minute). Maximum regional blood flow decreases during sleep occurred in the brainstem-cerebellar (-25.1 percent), right inferior temporal (-23.1 percent) and bilateral frontal (-18.9 percent) regions (p less than 0.05). In patients with narcolepsy, mean hemispheric Fg while awake was 80.5 +/- 13 ml per 100 gm brain per minute. During REM sleep (n = 2), mean hemispheric Fg increased by 9.8 percent concurrently with large increases (+34.6 percent) in brainstem-cerebellar region flow. During stages I and II sleep without REM (n = 6), there were significant increases in mean hemispheric Fg of +/-20.2 percent (p less than 0.01) and brainstem-cerebellar Fg of 38.0 percent (p less than 0.01), just the opposite of changes in normals. In narcolepsy, there appears to be a reversal of normal cerebral deactivation patterns, particularly involving the brainstem, during stages I and II sleep.

Adult↗
PubMed1979

Automated measurement of alpha, beta, sigma, and theta burst characteristics.

An automatic system was used for the selection and analysis of alpha, beta, and theta waveforms occurring in the awake and REM sleep states and sleep spindles occurring in stage 2 sleep. Two nights of sleep were analyzed for each of five normal subjects in each of five age groups: 3--5; 13; 25--34; 43--53; and 67--79 years of age. The waveform frequencies, length, and rate of occurrence were measured. No age-related changes were found in the alpha frequency (except for the younger group). No significant age differences were found in the beta and theta frequencies in the awake state. During REM sleep, the average beta and theta frequencies of the two youngest groups were significantly different from those of the three older groups. The average frequency of stage 2 sleep spindles of the two youngest groups was less than that in the middle group; the average spindle frequency of this group was significantly less than that of the two older groups. The number of spindles per minute was significantly less for the younger group and significantly more for the 25- to 34-year-olds.

Adolescent↗
PubMed1978

Impotence and blood pressure in the flaccid penis: relationship to nocturnal penile tumescence.

Evaluations of nocturnal penile tumescence (NPT) and penile blood pressure were performed on (1) a group of nondiabetics with normal NPT, (2) a group of nondiabetics with abnormally diminished NPT, and (3) a group of diabetics with abnormally diminished NPT. The 12 subjects in each group complained of impotence. Analysis of blood pressure data taken before the NPT evaluation suggests the possibility of selective low arterial blood pressure in impotent patients who show no obvious signs of other vascular disorders.

Blood Pressure↗
PubMed1978

Nocturnal penile tumescence and diagnosis in diabetic impotence.

The authors conducted a study of nocturnal penile tumescence (NPT) in 35 diabetic men, aged 33 to 70, who complained of impotence and in 35 age-matched control subjects. EEGs and other measurements showed that the diabetic men as a group exhibited significant reductions in the total amount of NPT and in the amount and frequency of full erection, thus suggesting that impotence in this cohort was organogenic. Although NPT monitoring represents an advance over the less precise traditional procedures for the differential diagnosis of impotence, the authors stress the need for more research in this area.

Adult↗
PubMed1978

Effects of high ambient temperature on sleep in young men.

Each of 10 normal subjects had 4 nights of laboratory-monitored sleep, consisting of adjustment, baseline, high blanket temperature (HBT), and recovery nights. EEG-EOG recordings were made on each night; rectal temperature, heart rate, body weight, and ambient temperatures were monitored throughout the last 2 nights. On the HBT night, subjects had less total sleep time, more frequent and longer awakenings, greater shifting among sleep stages, decreased amounts of stage 1 REM and stages 3 + 4, and delayed onset of deep sleep (stages 3 and 4). Body temperature was elevated to a relatively constant level of 37 degrees C on the HBT night, but gradually decreased from 36 degrees C to 34.5 degrees C across the recovery night. Heart rate decreased at a linear rate on both the HBT and recovery nights, but was 15 beats/min faster on the former. Subjects experienced liquid loss of 1.25 kg on the HBT night, but had a full recovery by the following evening.

Adult↗
PubMed1977

Ontogeny of delta activity during human sleep.

The study describes the ontogenetic and time-related changes in peak amplitude, frequency, and incidence of delta waves of twenty-five normal subjects between the ages of 3 and 79 years of age. All slow waves greater then 5 muV in magnitude and between 0.5 and 3.0 c/sec were analyzed for the first 6 h of the night's sleep. In this study increasing age was accompanied by decreases in average peak amplitude of delta waves over 5 muV, slowing of delta frequencies, and decreases in incidence of waves greater than 20 muV. Across 2-h epochs of the night there were tendencies for the average peak amplitude of delta waves to decrease, for the average frequency for a given amplitude range to decrease, and for the incidence of low-amplitude delta waves to increase and high-amplitude waves to decrease. The incidence of waves greater than 5 muV remained constant across ages and epochs. Frontal channel delta waves exhibited an age-group difference whereas no such difference was apparent for central channel delta activity, suggesting that the frontal channel may possess advantages over the central because of greater sensitivity to age related changes.

Adolescent↗
PubMed1977

Sleep disorders.

Explore the source record for details and available documents.

Animals↗
PubMed1977

Nocturnal erections, differential diagnosis of impotence, and diabetes.

In this study it is shown that monitoring of nocturnal penile tumescence (NPT) is an objective method for determining the erectile status of patients who complain of impotence. The characteristics of 11 diabetic patients with abnormal NPT, 11 patients with normal NPT and no medical disorders, and 11 normal men are presented. Also described are several sociodemographic characteristics of the first 100 patients undergoing an NPT evaluation as part of a screen for patients seeking implantation of a penile prosthesis. It is suggested that NPT monitoring should be a component of the differential diagnosis procedure for every patient who complains of impotence and that it provides a tool for the concentrated study of the mechanisms of erection and impotence.

Adult↗
PubMed1976

Dose-related sleep disturbances induced by coffee and caffeine.

In a 13-night sleep laboratory study, each of 18 normal young adult males twice received 1 cup of warm water, 1-, 2-, and 4-cup equivalents of regular coffee, a 4-cup equivalent of decaffeinated coffee, and a 4-cup equivalent of caffeine. All beverages were administered 30 min before bedtime according to a balanced Latin-square design. Regular coffee produced dose-related changes in most standard electroencephalogram-electrooculogram (EEG-EOG) sleep parameters, and the 4-cup equivalents of regular coffee and caffeine produced equivalent effects. Decaffeinated coffee had no effect. Regular coffee and caffeine caused rapid eye movement (REM) sleep to shift to the early part of the night and stages 3 and 4 sleep to shift to the later part. Coffee also produced dose-related changes in several subjects estimates of sleep characteristics. These results suggest that coffee and caffeine may be used in normal subjects to induce symptoms mimicking those of insomnia. Such a tool should promote further understanding of insomnia.

Adult↗
PubMed1976

Automated sleep EEG analysis applied to the evaluation of drugs: illustration by study of clorazepate dipotassium.

An automated sleep EEG analysis system was used to evaluate the effects of clorazepate dipotassium in normal subjects. Ten young-adult men slept 18 consecutive nights in the laboratory. On days 8-15 clorazepate (7.5 mg) was administered three times daily; on days 5-7 and 16-18 a placebo was administered in a similar fashion. The drug reduced amounts of alpha and delta activity and increased the amount of beta activity and the number of spindles. These effects generally persisted through the 3 day placebo recovery period. Our results suggest that sleep EEG waveform descriptors are sensitive indicators of drug activity and that beta activity in particular may be useful in the detailed description of various drug effects.

Adult↗
PubMed1976

Psychological screening of impotent men.

Rapid advances in methods of treating sexual impotence have produced concomitant demands for more specific diagnosis and determination of prognosis. Herein are presented guide lines for a rapid screening procedure that has diagnostic and prognostic utility. Use of 2 decisional rules for the Minnesota Multiphasic Personality Inventory, an easily administered and scored psychological test, can provide assistance to the urologic surgeon in determining the suitability of a candidate for a corrective operation. Case histories illustrate the value of this test in making treatment recommendations and assessing prognosis.

Adult↗
PubMed1976

Stress, cardiac activity and sleep.

An overview is presented of the relationship between cardiovascular activity and sleep, emphasizing the interrelations between stage of sleep and cardiovascular dysfunction. Possible implications of the data are discussed, especially in relation to stress-related factors and possible treatment regimens.

Cardiac Surgical Procedures↗