Biomedical subjects
R Taylor
Publications and source records attributed to R Taylor.
Fenclofenac-secondary effects upon the pituitary thyroid axis.
To elucidate the mechanism of suppression of TSH responsiveness to TRH induced by the initiation of fenclofenac therapy, the early period of drug administration was examined in detail and the effect of the drug during a thyrotrophin releasing hormone infusion was assessed. In addition, the effect of fenclofenac upon the response of ACTH, cortisol, growth hormone and prolactin to insulin-induced hypoglycaemia was examined. The effect of fenclofenac upon an equilibrium dialysis method for estimating free thyroid hormones was evaluated and was found to be insignificant within the therapeutic concentration range of the drug. A sharp, short-lived rise in free thyroxine (21.7 +/- 2.0 to 26.8 +/- 1.9 pmol/l; P less than 0.03) was observed 60 min after the first dose of fenclofenac. Repeated peaks of free thyroxine during chronic fenclofenac treatment, superimposed upon the previously described steady decline of free and total serum thyroxine, are postulated to cause the observed suppression of TSH release which is present only until free and total serum thyroxine levels reach their nadir. The time course of the changes seen during thyrotrophin releasing hormone infusion suggested that the pituitary suppression was secondary to a rise in free thyroxine. The responses to hypoglycaemia of those pituitary hormones examined were not affected by fenclofenac.
The endocrine and metabolic effects of cimetidine.
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Ophthalmic findings among one thousand inhabitants of Rarotonga, Cook Islands.
A survey of 986 Polynesians was conducted in Rarotonga, Cook Islands, for the complications of diabetes. The ophthalmologists in the team made a general assessment of eye health. Trauma was a major cause of blindness. Diabetic retinopathy, trachoma, cataract and macular degeneration were not common findings. The initial criteria of nuclear cataract were pigmentation or opacification with loss of fetal suture detail. This was invalidated by the finding in young adults of enhanced pigmentation may augment the intrinsic filter of near ultraviolet light. Of the 118 people with chorioretinal scars, 25 shared features with cases reported from the Pacific region attributed to filariasis. The majority, however, were typical of toxoplasmosis. Cases of pseudoexfoliation were rare. This is surprising in view of the high prevalence reported among Australian Aborigines at a comparable latitude.
Prospects and problems in the definition and standardization of immunofluorescence. I. Present levels of reproducibility and disease specificity of antinuclear antibody tests.
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A placebo-controlled trial of UV-A phototherapy for the treatment of uraemic pruritus.
The effect of ultraviolet A phototherapy on uraemic pruritus was investigated in a placebo-controlled trial. Equivalent and significant reduction of itch was noted in both placebo and treatment groups as assessed by analogue scales and interviews. This reduction in itch could have been the result of either a placebo response or a biological effect of blue light.
Plasma glucose distributions in two pacific populations: the bimodality phenomenon.
The frequency distribution of plasma glucose concentrations in certain populations show two distinct sub-groups, viz. the non-diabetic group and a hyperglycaemic group. The two groups show up as a double peak (bimodality) in the best-fit frequency distributions of log plasma glucose, and the separation or cut-off point where the two curves intersect, gives an indication of the plasma glucose level at which diabetes could be diagnosed. Venous plasma glucose concentrations two hours after a 75 gm oral glucose load were determined in the Micronesian population of Nauru and the urban Polynesian population of Western Samoa, in subjects aged 20 years and over. Both communities exhibit bimodal frequency distributions of plasma glucose in the upper age groups in both sexes. In the younger age groups the frequency distribution of plasma glucose typically follows the usual unimodal Gaussian curve. However, the high prevalence Nauruans show the bimodal form in all groups except the youngest males. The data show that among these two communities, as with the Pimas, the frequency distribution of plasma glucose concentrations can be used to separate the population into normal and hyperglycaemic groups.
Characteristics associated with diabetic retinopathy in Nauruans.
A recent epidemiological survey of the whole adult Micronesian population of Nauru has confirmed that Nauruans, along with Pima Indians, suffer the highest rate of abnormal glucose tolerance yet recorded. To establish the morbid effects of hyperglycaemia in this population, all responders to the diabetes survey were concurrently examined for diabetic retinopathy. In diabetic subjects, the crude prevalence of retinopathy was 24%. Specific rates were determined at various levels of the following characteristics: age, 2 hour post-load plasma glucose, body mass index, duration of diabetes and systolic blood pressure. Prevalence was found to rise with increasing 2 hour plasma glucose and duration, to fall with increasing body mass index and to have a quadratic relationship with age and systolic blood pressure. The multiple logistic regression model was used to determine whether the selected characteristics were significant in increasing the risk of retinopathy. Body mass index and systolic blood pressure did not contribute significantly to this risk after controlling for age. Increasing 2 hour plasma glucose significantly increased the risk of retinopathy, and duration of disease was the strongest predictor variable. This study shows that the consequences of hyperglycaemia in this Micronesian population are comparable to those already documented in European and American Indian communities.
Sensitivity to reinforcement in concurrent arithmetic and exponential schedules.
The generalized matching law states that the logarithm of the ratio of responses emitted or time spent responding in concurrent variable-interval schedules is a linear function of the logarithm of the ratio of reinforcements obtained. The slope of this relation, sensitivity to reinforcement, varies about 1.0 but has been shown to be different when obtained in different laboratories. The present paper analyzed the results from 18 experiments on concurrent variable-interval schedule performance and showed that response-allocation sensitivity to reinforcement was significantly smaller when arithmetic, rather than exponential, progressions were used to produce variable-interval schedules. There were no differences in time-allocation sensitivity between the two methods of constructing variable-interval schedules. Since the two laboratories have consistently used different methods for constructing variable-interval schedules, the differences in obtained sensitivities to reinforcement are explained. The reanalysis suggests that animals may be sensitive to differences in the distribution of reinforcements in time.
Changing established behavior to cut health costs.
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Many questions remain unanswered concerning Medicare reimbursement by diagnostic groupings.
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Diabetic retinopathy in a natural population.
Most epidemiological studies of diabetic retinopathy have been based on clinic populations. This produces a bias for the more severe cases and later stages of the disease. To avoid this bias, 1567 Micronesian adults of Nauru (82% of total adult population) were examined. Diabetic retinopathy was classified by both the World Health Organization (WHO) criteria and the Airlie House reference photographs. Results were subject to multiple logistic regression model analysis. Diabetic retinopathy was present in 7% of the general population and in 24% of diabetics. Of the signs, microaneurysms and microhaemorrhages were the most important, being present alone in 19.5%; and in 68.1% when associated with exudates. Proliferative retinopathy was present in 4.5% of cases. Exudates alone were found in two cases (2.2%). Duration of diabetes was the strongest predictor variable and increasing two-hour plasma glucose levels significantly increased the risk of developing retinopathy.
Cancer in Solomon Islands 1970-82.
An analysis of the pathology reports of cancer at the Central Hospital, Honiara, Solomon Islands from 1970 to 1982 revealed that skin cancer, lymphohaemopoietic malignancy, cancer of the digestive organs and oral cancer were the most common cancers in males, and that cancer of the genito-urinary organs, skin cancer, breast cancer and lymphohaemopoietic malignancy were the most common cancers in females. Leukaemia and lymphoma were the most common cancers diagnosed in children. Although this is a selected series, there are definite similarities with cancer data reported from Papua New Guinea, and significant differences from patterns of cancer reported from Australia. Cancer of the mouth and liver appear to be more common in Solomon Islanders, and cancer of the large bowel and lung less common compared with Australians. These differences probably relate to the effect of different environmental agents. The present prospects for prevention and control of cancer in Solomon Islands is discussed.
Chest pain of uncertain origin in patients admitted to a coronary care unit.
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The prevalence of diabetes mellitus and impaired glucose tolerance in Melanesians and part-Polynesians in rural New Caledonia and Ouvea (Loyalty Islands).
The study of different ethnic groups living in the same physical environment provides the opportunity to examine interaction of genetic and environmental factors in the aetiology of diabetes mellitus. In rural New Caledonia, the prevalence of diabetes was higher in part-Polynesians than in Melanesians: males - 6.6 versus 0.5%; females - 6.3 versus 3.5% respectively. The prevalence of abnormal glucose tolerance (impaired glucose tolerance and diabetes) was 11.5 and 15.7% in part-Polynesian males and females, respectively, and 4.7 and 9.2% in Melanesian males and females. Mean age and degree of obesity in these ethnic groups were sufficiently similar to suggest that these factors played no significant role in the difference in diabetes prevalence. Furthermore, adjustment of relative risk of impaired glucose tolerance and diabetes for age and obesity indicated that the modest differences between groups were not responsible for the observed variation in diabetes prevalence. The differences in prevalence of impaired glucose tolerance and diabetes between Melanesians and part-Polynesians may be genetically determined, although the role of certain environmental factors other than obesity, e.g. differences in physical activity or qualitative aspects of diet, cannot be excluded.
Impacted common bile duct stones.
The impacted common bile duct stone can be managed either surgically or radiologically using methods such as percutaneous basket extraction or endoscopic papillotomy. At operation, if an impacted common bile duct stone cannot be removed by the usual methods, duodenotomy and sphincteroplasty are indicated. If the patient's condition is good, sphincteroplasty should not be avoided in the belief that other means of stone removal are superior. However, if the patient's condition is not ideal, sphincteroplasty should be deferred in favor of delayed removal by percutaneous or endoscopic techniques. In patients without percutaneous access to the biliary tree, endoscopic papillotomy can be effective in removing impacted stones, or at least in relieving the obstruction and allowing improvement in the patient's condition before surgical intervention is attempted.
Cortisol creatinine ratio in normal pregnancy.
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Pathologic predictors of recurrence in stage 1 (TINOMO) breast cancer.
A group of 122 consecutively treated pathologic Stage 1 (TINOMO) patients with cancer of the breast were studied to define histopathologic predictors of recurrence. Lymphatic invasion was the most significant predictor of recurrence; recurrence was present in 32% (8/25) of patients who had lymphatic invasion and in 10.3% (10/97) of patients who did not (P = 0.006). Histologic type was also predictive of recurrent disease. Eighteen per cent (18/101) of patients with invasive ductal or lobular carcinoma developed recurrent disease, while none of the group of 21 patients with medullary carcinoma, tubular carcinoma, colloid carcinoma, Paget's disease, and intraductal carcinoma with minimal invasion suffered a recurrence (P = 0.036). Vascular invasion, grade of malignancy, cellularity, presence or absence of circumscription, cellular infiltrate, fibroblastic response, neural invasion, and necrosis were not significant predictors of recurrence. Multiple logistic regression analysis of patients with invasive ductal or lobular carcinoma confirmed the results for individual factors, that only patients with lymphatic invasion were at higher risk of recurrence.