Biomedical subjects

D B Wexler

Publications and source records attributed to D B Wexler.

28 records · Page 2Linked to original sources

PubMed1985

Sleep-wake stages during the subjective night of the squirrel monkey.

The study of the circadian sleep-wake cycle is beset by unique technical challenges. Continuous polygraphic recordings are necessary to characterize circadian phenomena; however, the traditional method of recording sleep at high (15 mm/sec) chart speed is impractical for continuous animal studies that may last several weeks at a stretch. A system to determine four sleep-wake stages (awake, transitional, non-REM, REM) from low chart speed (1.5 mm/sec) recordings was developed and validated by direct behavioral observation using four adult male squirrel monkeys prepared for chronic recording of EEG, EOG and EMG. The polygraphic stages "transitional," non-REM and REM were highly correlated with behavioral observations of sleep, although individual sleep stages could not be resolved by behavioral parameters alone.

Animals↗

PubMed1985

Circadian sleep-wake cycle organization in squirrel monkeys.

To investigate the relationship between circadian rhythms of body temperature and sleep-wake stages, four squirrel monkeys were prepared for unrestrained monitoring of temperature, locomotor activity, electroencephalogram, electroculogram, and electromyogram. Continuous records for each animal were made for several 12-h light-dark (LD) cycles and then after a few days in constant illumination (LL). All animals maintained consolidated sleep-wake cycles and had a longer circadian period (mean 24.7 h) in LL than in LD (mean 24.1 h). The increased period reflected greater time per circadian cycle spent awake in LL (mean 14.0 h) than in LD (mean 12.8 h). Total night NREM sleep was less in LL (mean 6.5 h) than in LD (mean 8.2 h). Sleep onset occurred at later phases in LL (187 +/- 6 degrees) than in LD (170 +/- 2 degrees). Because the circadian phase measure of NREM sleep was unchanged between LD and LL conditions, the difference in sleep onsets reflected balanced changes in NREM circadian waveforms. Wake-up phases were the same in both conditions (mean 342 degrees). In summary, during free run squirrel monkeys maintain a stable consolidated circadian sleep-wake cycle with a period greater than 24 h, but they exhibit only minimal internal phase restructuring.

Animals↗

PubMed1985

Seclusion and restraint in 1985: a review and update.

The 1982 Supreme Court decision in Youngberg v. Romeo gave mental health professionals flexibility to exercise professional judgment in using seclusion to control violent patients, and also suggested that seclusion and restraint might be used when patients exhibit disruptive behavior that may lead to violence. The authors reviewed 13 studies of seclusion and restraint in adult inpatient psychiatric settings to define indications for use. They found that seclusion and restraint practices varied widely depending on the population served and the philosophical orientation of the hospital staff, and were more often used to contain behavior that might lead to violence rather than to control violent behavior itself. They conclude that there is overwhelming empirical support for using seclusion and restraint to limit the progression of disruptive behavior to actual violence, but that the decision to do so should be based on sound clinical judgment.

Dangerous Behavior↗

PubMed1985

APA's model law: a commitment code by and for psychiatrists.

The author argues that the APA model law is seriously flawed because it lacks sufficient mechanisms for questioning the judgment of psychiatrists throughout the commitment process and for ensuring the best disposition of patients. By failing to provide for independent screening of commitment petitions, to mandate multiple psychiatric evaluations of respondents, to provide indigent respondents a free psychiatric examination to help them prepare for the commitment hearing, and to address the shortcomings of legal advocacy, the model law sets the stage for improper or unwarranted commitments. In addition, the law circumvents the rights of patients admitted on emergency status to refuse treatment throughout the entire evaluation period, which can last up to 14 days.

Commitment of Persons with Psychiatric Disorders↗

PubMed1984

Effects of a muramyl dipeptide on the temperature and sleep-wake cycles of the squirrel monkey.

The circadian sleep-wake and body temperature cycles of squirrel monkeys were monitored continuously in an environment free of time cues before and after a 50-nmol injection of a synthetic muramyl dipeptide (MDP) either 1 h after wake-up time (subjective day) or just before sleep time (subjective night). At both phases decreases in percent time awake (relative to saline controls) were observed. After administration of MDP early in the subjective day, the animals exhibited alert wakefulness only 47.4% of the daytime, compared with a mean 86.7% of daytime after a saline control injection. The transitional stage was significantly elevated from 6.2 to 28.7% of time after MDP. Nonrapid-eye-movement (REM) sleep was elevated in four of five animals, but in the fifth animal, which had the least consolidated base-line sleep-wake pattern, a small decrease in non-REM sleep was seen. Regression analysis demonstrated a significant (P less than 0.01) relationship between the degree of sleep-wake consolidation and the effect of MDP on non-REM sleep. Normal sleep behaviors and spontaneous arousals were observed. MDP given at the circadian nighttime of two animals resulted in sleep and transitional episodes occupying 84% of the subjective night vs. 73% of time asleep after control injection. Again, these were mostly transitional and non-REM sleep stages, and they persisted 4-5 h into the predicted circadian daytime. REM sleep appeared to be suppressed in the early hours after injection at either time of day.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1982