Psychiatrists' attitudes to euthanasia.
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Attitude of Health Personnel↗
Biomedical subjects
G Pike
Publications and source records attributed to G Pike.
Perception and recognition of normal and negative faces: the role of shape from shading and pigmentation cues.
A face is surprisingly difficult to recognise when presented in photographic negative, and negation has also been shown to affect simple perceptual judgments about a face. Two possible explanations for this effect are examined. In the shape-from-shading explanation it is argued that negating an image results in an impossible pattern of shading, and that this disrupts the formation of a three-dimensional representation of the surface geometry of the face. In an alternative account for this effect it is suggested that identification errors occur as a consequence of changes to the apparent pigmentation of the face caused by negating the image. Three experiments are reported which are designed to test these explanations by using novel colour-image transformations in which the hue and luminance components of images are independently manipulated. The results of these studies suggest that although changes to the apparent pigmentation of a face might result in identification errors in some situations, the loss of shape-from-shading cues is a more important cause of the negation effect. The role of these two sources of information in the recognition of normal faces is also discussed.
Face↗
Physiological outcome following laparoscopic highly selective vagotomy. A controlled study in a pig model.
Open highly selective vagotomy (HSV) has withstood the rigors of objective evaluation to become the optimal surgical treatment for chronic duodenal ulcer refractory to medical therapy in many centers. Laparoscopic HSV has not been subjected to the same scrutiny before entering clinical practice. A controlled animal study was conducted to demonstrate the physiological validity of laparoscopic HSV. Experimental groups underwent laparoscopic and open highly selective vagotomies, and control groups underwent a sham laparoscopic gastric mobilization or no operative procedure. Gastric acid output was measured by an aspiration technique, liquid gastric emptying was calculated by the double sampling technique of George, and gastroesophageal reflux was assessed by 8-h ambulatory pH monitoring. Laparoscopic HSV was as effective as its open counterpart in reducing basal acid output, and laparoscopic HSV did not interfere with liquid gastric emptying in contrast to open HSV. Neither open nor laparoscopic HSV was observed to precipitate gastroesophageal reflux. These data suggested that the continued use of laparoscopic HSV in clinical practice is appropriate.
Animals↗
An outbreak of illness among schoolchildren in London: toxic poisoning not mass hysteria.
STUDY OBJECTIVE: To determine the cause of an outbreak of acute gastrointestinal illness that occurred shortly after lunch in children attending a school in London, UK. DESIGN: A questionnaire survey of children at the affected school was carried out on the day after the incident. Microbiological, environmental, and toxicological investigations were also undertaken. SETTING: A school in London, UK. PARTICIPANTS: Altogether 374/468 (80%) of the children who had eaten lunch at the school on the day of the incident completed a questionnaire. MAIN RESULTS: There was a significant association between illness and the consumption of raw cucumber (relative risk = 6.1; 95% confidence interval 2.2, 16). Microbiological investigation of the foods served at lunch did not show any pathogens and toxicological investigations suggested that the cucumbers were contaminated by a pesticide. CONCLUSIONS: Although the outbreak displayed several typical features of mass psychogenic illness, the most probable cause was a toxic chemical present in cucumber served at lunch. Those responsible for investigating outbreaks of illness should be aware of the possible toxicological causes and the appropriate modes of investigation. They should be wary of too readily attributing a psychogenic cause to unusual outbreaks of acute illness in schoolchildren.
Acute Disease↗
Short fat questionnaire: a self-administered measure of fat-intake behaviour.
A brief questionnaire has been developed to measure behaviour related to dietary fat intake. It is self-administered and self-coded. Mean completion time is about three minutes. Criterion validity was assessed by comparison with a well-established food frequency questionnaire using 124 adults from Newcastle and Sydney. The correlations with the questionnaire scores were: r = 0.55 for total fat as a percentage of total energy, r = 0.67 for saturated fat as a percentage of total energy, and r = 0.44 for polyunsaturated to saturated fat ratio. Reproducibility was assessed by re-use by 25 subjects after seven to nine months (r = 0.85). When used in a community survey of other 300 randomly chosen people in the Hunter Region, the mean scores for men and for women and among different age groups were significantly different. The questionnaire was strongly associated with other scales measuring attitudes, behaviour and knowledge related to low-fat diets. The questionnaire appears suitable for rapid self-assessment by subjects, and as it directs their attention to aspects of their diet which might need improvement, it could be used for health education. It might also be used for epidemiological studies to rank subjects broadly according to their fat-intake behaviour.
Adolescent↗
Future time perspective: adolescents' predictions of their interpersonal lives in the future.
This study investigated adolescent future time perspective. The interpersonal subscale of the Future Likelihood Inventory was administered to a sample of adolescents aged 15 to 20 years. Based on the results of this study of interpersonal life projections, it appears that adolescents do not perceive divorce in their future. However, periods of singlehood, widowhood, and nuclear family life are perceived as extremely likely, particularly among female adolescents. Differences in future time perspective were revealed for gender but not age.
Adolescent↗
Effect of Senokot on rat intestinal electrolyte transport. Evidence of Ca++ dependence.
The mechanism of action of Senokot, a widely used laxative, has not been established. Senokot was given orally to rats 8-14 h before intestinal water and electrolyte transport were studied. Senokot significantly decreased colonic and jejunal water absorption measured in vivo by the single-pass perfusion technique. The Senokot changes were not associated with changes in jejunal or colonic histology or adenylate cyclase activity or colonic cyclic adenosine monophosphate content. Senokot also altered active electrolyte transport in rat descending colon as measured by the Ussing chamber-voltage clamp technique. These changes consisted of an increase in short-circuit current and a decrease in active Na and Cl transport that was due to a decrease in the mucosal-to-serosal fluxes. The changes in active electrolyte transport were dependent on Ca++ in the serosal but not the mucosal bathing solution. In contrast, addition of 10(-4) M verapamil to the serosal surface did not alter the Senokot effect. In spite of a dependence on serosal Ca++, Senokot did not alter 45Ca++ entry across the colonic serosal surface. The phospholipase A2 inhibitor quinacrine (10(-4) M) also did not alter the effect of Senokot on colonic Na and Cl transport. Senokot alters active colonic Na and Cl transport via a presently unknown mechanism that is dependent on serosal Ca++.
Adenylyl Cyclases↗
Calcium dependence of serotonin-induced changes in rabbit ileal electrolyte transport.
These studies describe the calcium dependence of the serotonin-induced changes in active electrolyte transport in rabbit ileum in vitro. In the presence of a standard calcium concentration (1.2 mM) in the serosal bathing fluid, serosal serotonin caused a transient increase in short-circuit current and a prolonged decrease in net Na and Cl fluxes. Removing calcium from the serosal (no calcium plus 1 mM EGTA) but not the mucosal bathing fluid inhibited the serotoin-induced increase in ileal short-circuit current, and also completely blocked the serotonin effects on net Na and net Cl fluxes. This inhibition was rapidly reversed by readding calcium. Removing serosal calcium did not inhibit all active electrolyte transport processes, as the effect of a maximum concentration of theophylline (10 mM) was not altered. Similarly, d,l-verapamil, a calcium channel blocker, inhibited the serotonin-induced changes in short-circuit current and in net Na and net Cl fluxes, but did not alter the theophylline effects. In contrast, d-verapamil, a stereoisomer which does not block calcium channels, did not inhibit the serotonin-induced changes. The calcium dependence of these serotonin effects was associated with increased uptake of 45Ca into rabbit ileum, including increaed 45Ca uptake from the serosal surface. Serotonin also increased the rate of 45Ca efflux from rabbit ileum into a calcium-free solution, compatible with serotonin increasing the ileal plasma membrane permeability to calcium. It is postulated that serotonin affects active intestinal electrolyte transport by a mechanism dependent on serosal but not mucosal calcium that involves an increase in the intestinal plasma membrane permeability to calcium, and perhaps an increase in intracellular calcium.
Animals↗