Biomedical subjects
Publications and source records attributed to D Donald.
The synthesis and pharmacological evaluation of a new series of potent P2X(7) receptor antagonists is disclosed. The compounds inhibit BzATP-mediated pore formation in THP-1 cells. The distribution of the P2X(7) receptor in inflammatory cells, most notably the macrophage, mast cell and lymphocyte, suggests that P2X(7) antagonists have a significant role to play in the treatment of inflammatory disease.
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Organochlorine pesticides and polychlorinated biphenyls (PCBs) are ubiquitous and persistent in the environment. They are known to concentrate in cold environments as a result of progressive evaporation from warm regions, and condensation in colder regions. In this study we show that melting glaciers supply 50 to 97% of the organochlorine inputs to a subalpine lake in Alberta, Canada, while contributing 73% of input water. Tritium analyses indicated that during the mid- to late summer warm period, at least 10% of the glacial melt originated from ice that was deposited in 1950-1970, when it was more contaminated with organochlorines. This finding suggests that climate warming may cause melting glaciers to become increasing sources of contaminants to freshwaters. Organochlorines from glacial streams were largely in dissolved form because the organic-poor glacial clays had a limited sorption capacity for the more hydrophobic chemicals.
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OBJECTIVE: To evaluate specified biomedical, socio-economic, and psychosocial criteria as predictors of therapeutic success to optimize patient selection for continuous ambulatory peritoneal dialysis (CAPD) in a developing country. DESIGN: A retrospective cohort study investigating the relationship between episodes of peritonitis and exitsite infection, and predetermined biomedical, socioeconomic, and psychosocial data. SETTING: A CAPD unit in a large tertiary care teaching hospital. PATIENTS: All 132 patients entering the CAPD program between 1987 and 1991. RESULTS: Overall mean survival time on CAPD was 17.3 months. Peritonitis rates were high, especially among blacks. Multivariate analysis demonstrated that increased peritonitis rates were associated with age, black race, diabetes, and strongly so with several psychosocial factors. Because being black was strongly linked to poor socioeconomic conditions, repeat analysis excluding blacks showed the same associations with the above variables, but, additionally, several socioeconomic factors were associated with high peritonitis rates. No significant explanatory variables were shown for exit-site infections. CONCLUSIONS: The association of biomedical, socioeconomic, and psychosocial variables with high peritonitis rates has important implications for the selection of patients for CAPD in this setting.
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A single small percutaneous bone biopsy was obtained in 107 untreated patients with lymphoma as part of staging. Six out of 52 cases of Hodgkin's disease had positive bone biopsies and three of these relapsed. In 55 patients with non-Hodgkin lymphoma, nine out of 16 with nodular lymphocytic disease and only 12 of 39 with diffuse disease, had positive biopsies. The incidence of relapse and deaths over the time studied was not clearly related to the biopsy results. The results are similar to findings in other series where a larger bone sample was obtained. The value of a single small bone biopsy in lymphoma seems established.
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The possibility of the transformation of mycosis fungoides into a lymphoma of another histologic type is problematic. Convincingly illustrated examples are not to be found in the literature. We report on a well-documented case of a man who developed nodular sclerosing Hodgkin's disease 15 years after first presenting with mycosis fungoides.
Two patients are described with dermatitis herpetiformis and Sjögren's syndrome. The increased incidence of autoantibodies in dermatitis herpetiformis would suggest that this association is significant. Antinuclear antibodies commonly occur in dermatitis herpetiformis (Seah et al,, 1971) yet are rarely associated with autoimmune disease in these patients (Moncada, 1974). This report records two patients with dermatitis herpetiformis and Sjögren's syndrome.
A comparative study of the outcome of surgical treatment for thyrotoxicosis was carried out in two countries with dissimilar dietary iodine levels. In the area with a high iodine level (Iceland) the prevalence of post-operative hypothyroidism was five times lower, but recurrent hyperthyroidism was five times higher, than in the area with lower iodine levels (northeast Scotland). The total morbidity reached comparable levels in the two samples. The prevalence of positive thyroid antibody tests and serum thyrotrophin levels was lower and the functional capacity of the thyroid remnant higher in the area with the higher dietary iodine intake. The study provides further evidence that there are important regional differences in the prevalence of factors known to influence the response to surgical treatment of thyrotoxicosis which should be taken into account when planning treatment services.
A comparative study was made of thyroid function in samples of 'well' subjects, from separate geographical areas with dissimilar dietary iodine levels. In the area with the higher iodine level, Iceland, the prevalence of positive thyroid antibody tests and serum thyrotrophin levels were lower, while the capacity of the thyroid to respond to exogenous thyrotrophin was higher than in NE Scotland, an area with lower iodine levels. In contrast the prevalence of positive tests for another organ-specific antibody, gastric parietal cell antibody, was higher in Iceland. These observations are consistent with the reported differences in the incidence rates for thyrotoxicosis and gastric carcinoma in the areas studied. The results are in agreement with our findings in two groups of post-thyroidectomy patients from the same populations. This study provides support for the view that differences in the prevalence of constitutional and environmental factors in different populations contribute to the variation in reported outcome of treatment for thyroid disease.
A significant increase in non-organ specific autoantibodies is demonstrated in13 per cent of the sera from 202 patients with histologically proven malignancies, as compared with only 4 per cent of sera from 214 age and sex matched control patients. It appears that the incidence of autoantibodies is related to the histological type of the tumour but not to the presence or absence of tumour dissenmination. While the control group shows the expected increase in both incidence and titre of autoantibodies with increasing age, the malignant patients show no such pattern i.e. in cancer patients autoantibodies occur with equal frequency and at similar titres regardless of age. The absence of an age related increase in incidence and titre of non organ specific autoantibodies does not appear to have been reported previously. Our findings lend support to the hypothesis that cancer is associated with a breakdown of immunological surveillance, not only in old but also in young cancer patients. Thus the findings of non organ specific autoantibodies, especially to smooth muscle antigen, in an apparently healthy adult could be considered evidence of such a breakdown, carrying with it an increased risk of neoplasia.
In seventy-eight patients with alopecia areata, the incidence of auto-antibodies to smooth muscle was greater than that in an age and sex matched control population.
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