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Biomedical subjects

J B Knowles

Publications and source records attributed to J B Knowles.

33 records · Page 2Linked to original sources
PubMed1982

Definitions of REM latency: some comparisons with particular reference to depression.

Unlike sleep stages, which are assessed by standardized criteria, an informal survey by us showed that the definition of REM latency is relatively idiosyncratic. Differences in definition arise for two reasons: Differences in the definition of sleep onset, and the inclusion or exclusion of wakefulness that may occur prior to the first REM period. Seven definitions are identified. Each was applied to 70 records taken from 14 depressed patients, 5 remitted depressives, and 5 normal subjects. In all three samples, REM latencies calculated on the basis of the different definitions differed significantly. Reasons for adopting a common definition are discussed. It is suggested that, if established, the reliability and validity (concurrent and predictive) of the available measures would provide an empirical basis for selection.

Adult↗
PubMed1981

Sleep deprivation: outcome of controlled single case studies of depressed patients.

Six drug-free depressed patients, each of whom acted as their own control, were studied for eleven consecutive days during which they were twice deprived of sleep for either 36 or 40 hours. The sequence of events was baseline (3 days), SD, recovery (3 days), SD, recovery (3 days). Blind ratings of clinical state were made on the basis of four-hourly interviews (standardized for each case), which were videotaped; sleep was monitored by conventional electrophysiological methods. Sleep deprivation had a beneficial, but transient, effect on four of the six patients studied. Changes in sleep were unrelated to changes in clinical state.

Aged↗
PubMed1980

Sleep and depression: a case study of EEG sleep prior to relapse.

By chance, we were able to record for five consecutive nights the sleep of a 61-year-old woman before each of two successive depressive episodes. In this patient, marked changes in EEG sleep (notably a decline in "sleep efficiency") preceded both episodes. These changes are considered to be of predictive, but not of etiological, significance.

Bipolar Disorder↗
PubMed1979

Five variations of sleep deprivation in a depressed woman.

Systematic variation in aspects of the sleep-wakefulness cycle of a depressed woman showed that recovery occurred reliably after 19 to 20 hours sustained wakefulness, unrelated to diurnal rhythm. Depression returned during as little as 15 minutes sleep. The effect of sleep deprivation was a specific response, probably unrelated to REM sleep.

Aged↗
PubMedDate not supplied

Pulmonary deposition of calcium phosphate crystals as a complication of home total parenteral nutrition.

A patient on home total parenteral nutrition (TPN) developed a diffuse granulomatous interstitial pneumonitis secondary to calcium phosphate deposition. Calcium and phosphorus concentrations in the TPN formula were not unusually high, indicating that other factors contributed to calcium phosphate crystallization. The effects of duration of storage of the TPN formulation, solution temperature, pH, and magnesium concentration on calcium phosphate precipitation are discussed.

Adult↗