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Biomedical subjects

M W Johns

Publications and source records attributed to M W Johns.

12 recordsLinked to original sources
PubMed1977

Self-poisoning with barbiturates in England and Wales during 1959-74.

Hospital admissions due to acute barbiturate poisoning per million population in England and Wales have decreased since 1965 at about the same rate as NHS prescriptions for barbiturates. Admissions due to poisoning with other drugs have increased, but, largely because the benzodiazepine hypnotics and tranquillisers are much less toxic than the barbiturates that they are replacing, deaths from poisoning with all solids and liquids have decreased. The risk of death from self-poisoning associated with each barbiturate prescription has increased two and a half times since 1961, perhaps partly because greater quantities of barbiturate are being dispensed with each prescription and partly because patients for whom these drugs are still being prescribed would, in the event of an overdose, be unlikely to be found and admitted to hospital in time owing to their age and social circumstances. There is now little to justify prescribing barbiturate hypnotics or sedatives for anyone.

Barbiturates↗
PubMed1976

A warning device which indicates the stoppage of paper in an ink-writing recorder.

A simple and inexpensive warning device is described which indicates when the paper has stopped moving beneath the pens of an inkwriting polygraph. The device operates on the principle that the electrical resistance of the paper under the recorder pen is markedly reduced when the paper stops moving and is made wetter by the ink. A buzzer sounds within a few seconds of the paper stopping and so reduces the possibility of failing to record otherwise irretrievable information, for example during all-night recordings of the EEG in sleep research.

Electronics, Medical↗
PubMed1976

Factor analysis of analogue scales measuring subjective feelings before and after sleep.

A series of 18 visual analogue scales was used to report the subjective feelings of 38 healthy subjects on 732 occasions during experiments concerned with the quality of sleep. Factor analysis of scores from these scales, both for all subjects combined and within each of four subjects separately, yielded two factors consistently -- 'alertness' and 'tranquillity'. Scores derived from the first factor indicated that, in the laboratory setting levels of immediately after waking in the morning were reduced, in relation to those before falling asleep on the previous night.

Adolescent↗
PubMed1976

A transportable sleep recording system.

A system for monitoring sleep, which can be used in th ward without unduly disturbing either the patient or the medical and nursing staff, is described. The system records the electroencephalogram, electro-oculogram, the basal skin resistance and the galvanic skin resistance. In addition, the delta waves of the EEG are automatically counted and a histogram of their frequency plotted. The system allows a whole night's sleep recording to be compressed into just over a metre of paper.

Adult↗
PubMed1975

Factor analysis of subjectively reported sleep habits, and the nature of insomnia.

Factor analysis was performed on variables used to describe subjectively the sleep habits of three groups of subjects--male patients, female patients, and medical students. Similarities in the six factors from each analysis indicate the existence of dimensions of variation which are common to normal sleep habits and insomnia.

Adolescent↗
PubMed1975

Factor analysis of objective and subjective characteristics of a night's sleep.

Factor analysis was performed on objectively measured and subjectively reported characteristics of 46 nights' sleep in four healthy male subjects. The fragmentation of sleep by awakenings during the night, the delay before falling asleep, the total duration of sleep, and the amount of delta-wave sleep formed the bases of four separate factors.

Adult↗
PubMed1975

Variations in thyroid function and sleep in healthy young men.

1. The total serum thyroxine, tri-iodothyronine resin uptake, total plasma protein concentration and the free thyroxine index (FTI) were determined repeatedly, at 07.15, 13.00 and 22.30 hours over 4 days, in six healthy young men. 2. There was a significant diurnal variation in the total serum thyroxine concentration but this reflected changes in the binding capacity of serum proteins and in the total plasma protein concentration which could be explained by changes of posture. The FTI, and presumably therefore the free thyroxine concentration, varied very little with the time of day. 3. The FTI varied significantly from day to day in three of the six subjects, presumably as a result of changes in thyroxine secretion because the serum binding capacity did not vary. 4. The subjects' sleep at night was assessed by electro-encephalogram. In days when the FTI was highest for a particular subject his sleep was more fragmented by spontaneous awakenings, the amount of rapid-eye-movement sleep was reduced and that of delta-wave sleep was increased, implying that variations in thyroid function over a period of a few days in healthy subjects can be of physiological significance. The cause of these variations is uncertain.

Adult↗
PubMed1975

Sleep and hypnotic drugs.

In recent years the effectiveness of hypnotic drugs has had to be assessed in terms of a greatly increased knowledge of the physiology and pathology of sleep. The normal pattern of sleep and wakefulness involves a cyclic alternation between three rather than two basically dissimilar states of the brain and body - alert wakefulness, rapid-eye-movement (REM) sleep and non-rapid-eye-movement (NREM) sleep. The pattern of this alternation in individual people results from the interaction of many influences - biological (including genetic, early developmental and later degenerative influences), psychological, social and environmental factors, various physical and psychiatric disorders, and most drugs which affect the central nervous system. The quality of sleep is not related in any simple or constant manner either to its duration or to the proprotions of time spent in each stage of sleep. Among the disorders of sleep, insomnia is a far more common problem of medical management than are enuresis, narcolepsy, somnambulism or nightmares. With a few exceptions, most hypnotic drugs now in widespread use cease to be effective in treating insomnia after the first few nights. However, the ineffective treatment is often continued because insomnia will be even worse during the initial period of drug withdrawal. These factors and the toxicity of hypnotic drugs when taken in overdose make the long-term treatment of insomnia more difficult than was previously supposed. Barbiturates should no longer be prescribed. Some of the non-barbiturates, such as glutethimide and methaqualone, have no advantage over the barbiturates. The benzodiazepine hypnotics, nitrazepam and flurazepam, are less toxic in overdose and are relatively effective in treating insomnia. Chloral hydrate and its derivates are useful alternative drugs for short-term use. Measures to improve sleep without drugs deserve greater emphasis than they have had in the past.

Adult↗