Biomedical subjects
J E Cox
Publications and source records attributed to J E Cox.
Ineffectiveness of cholecystokinin in impairing runway performance.
We compared changes in runway performance by rats for sucrose reward following injections of the synthetic C-terminal octapeptide of cholecystokinin (CCK-8) with those seen after variations in food deprivation and injections of lithium chloride. No effects on running for either 10% or 30% sucrose were found following 0.5 to 4.0 micrograms/kg of CCK-8, though such doses suppressed 30-min sucrose intake up to 53%. Statistically reliable slowing of running for 10% sucrose was observed on two series of tests after 8.0 micrograms/kg of CCK-8. Running for 30% sucrose was not significantly affected by this dose. The general ineffectiveness of CCK-8 for producing decrements in running spread contrasts with significantly reduced performance after either reductions in food deprivation (21 h vs 12 and 3 h) or injections of 75 mg/kg lithium chloride. These results suggest that the mode of action of CCK-8 in reducing food intake is different than that produced by changes in hunger or by non-specific interference with motivation by malaise. The finding that CCK-8 can substantially reduce consumption with no apparent changes in appetitive motivation is consistent with the hypothesis that this substance acts only late in the meal to prematurely trigger satiety.
Blood test for equine cryptorchidism.
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Testosterone and corticosterone concentrations in the plasma of rats deficient in vitamin E.
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Factors affecting testis weight in normal and cryptorchid horses.
Testes were collected from normal and cryptorchid horses of a variety of breeds and ages and weighed after dissection from the epididymis. Scrotal testes grow little until the second winter of life and little thereafter, although a nearly mature body weight is reached by the end of the first winter. Scrotal testes in unilateral cryptorchids tend to be larger than those of normal stallions, sometimes exceedingly so, although occasional small scrotal testes are recorded. Inguinal testes show some tendency to grow during the second winter but the data are difficult to analyse beyond that age because of the transient nature of most cases of inguinal cryptorchidism. Abdominal testes do not appear to increase in size with age but if a unilateral abdominal cryptorchid has its scrotal testis removed, the remaining abdominally retained testis undergoes marked hypertrophy.
Secretion of free and conjugated steroids by the horse testis into lymph and venous blood.
In 3 testes of 2 adult Pony stallions under halothane anaesthesia, catheters were inserted into a vein and a lymphatic vessel in the spermatic cord and into a vein on the surface of the testis. Lymph and venous blood were collected from the catheters in the cord and p-aminohippurate (2% w/v, 0 . 1 ml/min) was infused into the vein on the testis to determine blood flow by dilution. After 1 h, 6000 i.u. hCG was injected i.v. and collections continued for 45 min. The testes weighed 126-176 g. Lymph flow was 20-150 microliter/min before hCG and 100-270 microliter/min after hCG; the range of blood flow, with a haematocrit of about 22%, was unchanged (27-47 ml/min) after hCG. The concentration of testosterone in spermatic venous blood rose from 6-20 ng/ml to 160-270 ng/ml within about 30 min after hCG. Peripheral levels rose from about 2 to 6 ng/ml and lymph levels increased from 9-20 to 34-150 ng/ml after hCG. In contrast, the concentrations of oestrone sulphate in spermatic venous blood were about 400 ng/ml, compared with about 250 ng/ml in peripheral blood, while lymph values ranged from 600 to 1500 ng/ml; hCG had no consistent effect. DHA and its sulphate were present in spermatic venous blood at concentrations (about 3 and 5 ng/ml respectively) slightly higher than in peripheral blood (1 . 7 and 2 . 5 ng/ml), but the sulphate was at a very much higher concentration in lymph (about 5 and 200 ng/ml respectively). These results indicate that testicular lymph is an important route for the secretion of conjugated steroids by the horse testis.
Mortality of nickel workers: experience of men working with metallic nickel.
The mortality of men employed in a plant manufacturing nickel alloys from metallic nickel and other metals has been examined. The plant has operated since May 1953, and 1925 men were identified who had been employed in the operating areas at the plant, other than as members of the staff, for a total of five or more years, excluding breaks. Analysis of samples of air obtained from personal samplers showed that since 1975 most of the men are likely to have been exposed to average concentrations of nickel of between 0.5 and 0.9 mg Ni/m3. All but 22 (1.1%) of the men were successfully traced to 1 April 1978 or until they died or emigrated. One hundred and seventeen had died. The numbers of deaths observed from cancers of respiratory and other sites, other respiratory disease, ischaemic heart disease, and other causes of death were compared with the numbers expected from national and local mortality rates. No evidence of the existence of any occupational hazard was obtained. The number of deaths from lung cancer (15) in men employed for five years or more is small. At 98% of the number expected at local rates it is statistically compatible with risks of between 0.5 and 2.2 times "normal."
Intragastric pair feeding fails to prevent VMH obesity or hyperinsulinemia.
Female rats with electrolytic lesions of the ventromedial hypothalamus (VMH) were pair fed with controls in a new paradigm in which food was delivered in normal temporal patterns, i.e., those of nonlesioned rats bar pressing for food. Lesions were produced after 6 days of adaptation to this regimen, and the experiment continued for 30 days postlesion. When they were killed, VMH rats contained substantially more carcass lipid than controls (20.4 vs. 12.4%) and were hyperinsulinemic (67.2 vs. 27.6 microunits/ml). Because these elevations developed in the absence of even minor disturbances in feeding patterns, these results support the view that VMH damage confers an essential metabolic bias favoring obesity. Separate VMH groups pair fed exclusively by either oral or intragastric routes exhibited virtually identical exaggerations in fat accumulation (18.4 and 17.7 g above controls, respectively) and plasma insulin (69.2 and 65.4 microunits/ml, respectively). Thus, contrary to a prediction of one form of Powley's (Powley, T. L. Psychol. Rev. 84:89-126, 1977) cephalic phase hypothesis, oropharyngeal stimulation and, hence, the cephalic responses of digestion are not critical for the metabolic disturbances that follow VMH damage.
Prior vagotomy blocks VMH obesity in pair-fed rats.
Previously vagotomized, ventromedial hypothalamus (VMH)-lesioned rats and sham-lesioned controls were maintained on an intragastric pair-feeding regimen in which nonvagotomized VMH rats deposit excessive fat. Hypothalamic lesions were produced after 6 days of adaptation to pair feeding, and the experiment continued for 30 days postlesion. Extent of vagotomy was determined with a multiple-regression procedure with cell loss in the dorsal motor nucleus of the vagus, fasting gastric contents, and basal pancreatic protein output as predictor variables. The correlation was 0.95 between this set of indexes and the adequacy of a vagotomy for preventing hypothalamic obesity. Thus, radical vagotomies precluded the typical accumulation of significantly increased levels of carcass fat in lesioned animals (16.3 vs. 14.0% for controls). VMH rats with less extensive transections accumulated substantially more fat (25.9%). This outcome suggests that vagotomy produces a specific blockade of lesion-produced disturbances in metabolism leading to obesity. It fails to support a previous suggestion that vagal section blocks VMH obesity merely as a nonspecific surgical restriction of food intake because vagotomy was effective even though its effects on food intake could not operate.
An analysis of 500 cases of equine cryptorchidism.
The authors analyse data collected over 23 years from 500 cryptorchid horses. They show that left- and right-sided abdominal cases occur with approximately equal frequency in ponies. Approximately half the right-sided unilateral abdominal cases have the epididymal tail descended while only 20 per cent of the left-sided cases do. These findings are briefly discussed. From their analysis of inguinal cryptorchidism the authors conclude that it is a relatively more complex phenomenon with incidence changing with age as well as breed. Right-sided retention predominates in young ponies, probably being an extreme expression of testicular hypoplasia, but in older ponies and in other types of horse, retention occurs equally on the left and right.
Adrenal-testis interaction in the stallion.
The authors describe the short and long term effects of synthetic adrenocorticotrophin and of cortisol on peripheral plasma testosterone concentrations in 2 stallions. A single injection of either hormone temporarily raised plasma testosterone concentrations but repeated injection (twice daily for 5 days) depressed plasma testosterone concentrations. Cessation of treatment was followed by a rise in plasma testosterone to concentrations higher than those in the pretreatment period. These findings are briefly discussed.
Suprapubic paramedian laparotomy for equine abdominal cryptorchidism.
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Atresia of the small intestine in lambs and calves.
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Laboratory methods of equine pregnancy diagnosis.
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Diagnosis of equine crytorchidism.
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Development of obesity in diabetic mice pair-fed with lean siblings.
The role of hyperphagia -n the obesity of the diabetic mouse, C57BL/6J db/db, was investigated. Ingestion patterns and the amount of food for diabetic mice were controlled by yoking their food intake to that of nonobese siblings obtaining their food by bar pressing. Over a period of 6 wk, young (initial ages were 28 days) pair-fed diabetic mice accumulated 42% more body weight and approximately five times more extractable carcass lipid than did their siblings. Weight gain and absolute levels of carcass fat were reduced in food-restricted siabetic mice compared with dbs on unrestricted food intake. However, carcass fat as percentage of wet carcass weight was virtually identical in the restricted and unrestricted dbs (47.6% vs. 49.6%). From these results it is concluded that the heightened adiposity of the diabetic mouse does not require hyperphagia for its expression and thus represents a metabolic obesity.
Letter: Diagnostic test for equine cryptorchidism.
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