Biomedical subjects
J Cairns
Publications and source records attributed to J Cairns.
Relationship of alkaline stress and acute copper toxicity in the snail Goniobasis livescens (Menke).
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REM latency and depression: computer simulations based on the results of phase delay of sleep in normal subjects.
A phase advance of the circadian rhythm of rapid eye movement (REM) sleep propensity relative to the sleep-wake cycle has been hypothesized to account for the abnormalities of REM sleep in depression. One implication of this hypothesis is that an acute phase delay of sleep in normal subjects should produce the same abnormalities of REM sleep. A further implication is that changes in REM sleep that occur in normal subjects with delay shifts of sleep of progressively greater magnitude describe those that occur during the course of a depressive episode. This hypothesis was tested by computer simulation using two equations which, given the data derived from normal subjects experiencing phase delays of sleep, generated the REM latencies expected during successive stages of a depressive episode. For severely depressed patients, the computer-generated data matched those found empirically. The known correlation between severity of depression and REM latency, and the REM latencies of recovered patients, are consistent with the hypothesis.
Effects of dazoxiben on exercise performance in chronic stable angina.
1 We have performed a double-blind, randomized, 7-d cross-over study of the thromboxane synthetase inhibitor dazoxiben (UK 37248) in 20 patients with stable coronary heart disease. 2 All patients had a history of exertional angina of greater than two years duration and no patient had suffered a myocardial infarction in the preceding twelve months. 3 All patients had a positive exercise stress test for myocardial ischaemia and 15 had undergone coronary angiography. All these patients had a 50% narrowing in at least one vessel. 4 All patients were on conventional anti-anginal medication and the doses of their various therapies remained unchanged in the three months prior to and during the study period. 5 Therapy with dazoxiben 200 mg four times daily produced no alteration in the subjective or objective features of angina in these patients. There was no alteration in angina attack rate, glyceryl trinitrate consumption or duration of treadmill exercise. 6 Dazoxiben produced a highly significant reduction in both the resting and the post-exercise levels of serum thromboxane B2 levels, although there was no significant difference between the pre-exercise and post-exercise values. 7 Dazoxiben is an effective inhibitor of the synthesis of thromboxane but it has no effect on the subjective or objective features of stable coronary disease. This would suggest that the production of thromboxane and the development of circulating platelet aggregates play no part in the mechanism of angina in patients with stable coronary heart disease.
Dose-response effects of ethanol on the sleep of young women.
In healthy young women, rapid eye movement sleep decreased, slow-wave sleep increased, sleep-onset latency decreased and late-night disturbance of sleep increased with increasing doses of alcohol.
Random components in mutagenesis.
The mutability of DNA varies enormously from one base pair to another. Part of this variation is due to the specificity of the reaction between mutagens and base, but much of the variation is due to unknown causes. A genetic system developed by Miller and colleagues allows the mutation frequencies of a large number of different base pairs in the lacI gene of Escherichia coli to be compared. For example, Coulondre and Miller found that the sites most readily mutated by UV light are almost 100 times more often mutated than the least susceptible sites. A recently completed study of mutagenesis with neocarzinostatin (NCS) in the lacI gene has prompted us to re-examine some previous studies, of mutagenesis in this gene. Our analysis, reported here, suggests that the mutations induced by certain mutagens fall into two classes: mutations in one class are clearly distributed non-randomly, that is, they are very common at some sites and significantly less common at others; mutations in the second class, however, occur at low frequency and appear to be randomly distributed. Both classes of mutations seem to occur only at damaged bases.
Effect of varying the time of sleep on sleep, vigilance, and self-rated activation.
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Dose-response effects of ethanol on the sleep of young men.
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Cocarcinogenesis and biological effects of tumor promoters. Conclusions and perspectives.
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REM sleep abnormalities in depression: a test of the phase-advance hypothesis.
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Aging and cancer as genetic phenomena.
Although the most frequently seen forms of cancer and the changes of senescence have in common the fact that they both occur in old age, their mechanisms are thought to be completely different. Because cancer is usually due to avoidable external agents (such as cigarettes, sunlight, peculiarities of diet, and certain particular hazards of the work place), it is considered a preventable disease. Many of the changes of senescence seem to be simply the inevitable corollary of our innate program of development; homo sapiens is designed to become an optimal, maximally viable product in the late teens, at the time of sexual maturity, and the same processes that lead to this optimalization also lead to a diminished fitness in later life. Although we may eventually abolish most sources of cancer, we should not expect to abolish senescence.
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.
The origin of human cancers.
The limited evidence available suggests that most human cancers are not caused by conventional mutagens but are more likely to be the result of genetic transpositions. Although the molecular biology of transposition is starting to be understood, the external factors that influence its frequency have not yet been studied in any detail.
The effects of a simulated refinery effluent and its components on the estuarine crustacean, Mysidopsis bahia.
The acute and chronic toxicities of a simulated refinery effluent and its components to Mysidopsis bahia were examined. The 96 hr LC50 for M. bahia was 4.7% of the Artificial Refinery Mixture (ARM). The mysid was more sensitive than an estuarine fish and grass shrimp, as well as 17 freshwater organisms previously tested. Fuel oil was the most toxic component of the ARM (96 hr LC50 0.73 mg/l) and contributed disproportionately to the toxicity of the mixture. Chronic exposure to 2.7% of the ARM formulation resulted in growth inhibition by day 8 and reproductive impairment. Long-term exposure to the 96 hr LC10 had deleterious effects on growth and/or reproduction for each component tested.
Accumulation and depuration of metals by duckweed (Lemna perpusilla).
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The inducible repair of alkylated DNA.
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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.