Randomization by cluster.
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Analysis of Variance↗
Biomedical subjects
A Donner
Publications and source records attributed to A Donner.
Effect of n-3 and n-6 fatty acids on 7,12 dimethylbenz (a) anthracene-induced mammary tumorigenesis.
Numerous studies have consistently shown that vegetable oils containing linoleic acid enhance mammary tumorigenesis more effectively than fish oils containing eicosapentaenoic and docohexaenoic acids. The purpose of this investigation was to study these and additional n-3 and n-6 PUFA, e.g., a-linolenic (a-LN) (18:3 n-3) and gamma-linolenic (GLA) (18:3 n-6) acid. Different oils were used as dietary sources of fatty acids: corn (CO) (61% LA); blackcurrant (BCO) (44% LA, 18% GLA and 16% a-LN); fish oil (FO) (mixed with corn oil, 12% LA and 24% EPA + DPA + DHA). Thirty-five-day-old female Sprague-Dawley rats were divided into 5 dietary treatment groups and were allowed to feed ab libitum on one of the test diets: I. BCO (23.5%); II. CO (23.5%); III. BCO (15.5%) + FO (8%); IV. FO (20.5%) + CO (3%); and V. BCO (20.5%) + FO (3%). From 48 to 52 days of age, rats in all five groups were fed rat chow. At 50 days of age, all rats were given 5 mg DMBA by oral intubation, and 2 days later the test diets were resumed until termination of the experiment. Analysis of tumor incidence, and multiplicity data for 5 diet groups indicated that rats fed 23.5% CO (II) exhibited enhanced mammary tumor yields when compared to animals on the remaining 4 diets in the order II greater than I, III, V greater than IV. Since the level of fat (23.5% w/w) was similar in all 5 diets, and body weight gain was in the order IV greater than II greater than I, the results of this study indicate that differences in tumor yields were related to fatty acid composition of diets. In support of this conclusion, fatty acid profiles of RBC and tumor phosphoglycerides reflected dietary fatty acid composition. In groups I and II, even though tumor levels of LA were similar, the levels of GLA, DHLA (20:3 n-6) and a-LN were higher in I compared to II, suggesting that these differences may be associated with lower yields of DMBA-induced mammary tumors in group I. Incorporation of marine type n-3 PUFA (EPA, DPA and DHA) in tumor PL was greater in Group IV compared to plant type n-3 PUFA (a-LN) in Groups I, III, and V. Since tumor yields were the lowest in Group IV, these results suggest that incorporation of marine type n-3 PUFA into cell membranes does not favor development of DMBA-induced mammary tumors.
9,10-Dimethyl-1,2-benzanthracene↗
Clinical trials of cyclosporin in IDDM.
The results of uncontrolled trials in immunomodulation of insulin-dependent diabetes mellitus (IDDM) led to randomized controlled trials in Canada and Europe. In the Canadian open study, the rate of clinical remissions (target control of glycemia maintained with less than or equal to 0.15 U.kg-1.day-1 insulin) was unexpectedly high among 81 subjects who had been treated with cyclosporin for at least 3 mo (mean serum trough levels approximately 125 ng/ml by radioimmunoassay). Subjects entered the study within 14 wk of onset of symptoms and received 6 wk of insulin therapy. The clinical remission rate at 1 yr was 46%; of these patients, 84% were not receiving insulin. An effect on beta-cell function was suggested by recovery of plasma glucagon-stimulated C-peptide levels into the normal range in many patients, with maintenance of levels through 1 yr in patients in remission. On the basis of these findings, the French and Canadian-European study groups conducted randomized double-blind controlled trials of cyclosporin, which confirmed the results of the open studies in terms of clinical remission. The Canadian-European study also demonstrated enhancement of beta-cell function by cyclosporin by 3 mo, which was maintained for 1 yr. In the Canadian open study, most patients relapsed within a few weeks after discontinuation of cyclosporin, indicating the need for longer-term immunomodulatory therapy for maintenance of remission. The nature and degree of structural change in kidney biopsies from patients in these studies are under assessment. The results strongly support the hypothesis that autoimmune mechanisms mediate beta-cell damage in many patients with IDDM.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗