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Biomedical subjects

A Donner

Publications and source records attributed to A Donner.

At least 163 records · Page 9Linked to original sources
PubMed1982

An empirical study of cluster randomization.

Increasing attention has been given recently to the methodological issues associated with randomization of clusters rather than individuals in lifestyle intervention trials. These issues are explored through an empirical study of the 'effective sample size' imposed by randomization of three experimental units frequently considered in epidemiological research: the spouse pair, the general practice, and the large geographic area (county). The measurement of within-cluster dependence for a dichotomous outcome variable is also discussed, and a relationship shown between Fleiss's kappa and Cornfield's inflation factor.

Epidemiology↗
PubMed1982

Design considerations in the estimation of intraclass correlation.

The design of family studies to estimate the value of an intraclass correlation coefficient p is considered when ni individuals are to be selected from each of k families, i = 1, 2, ..., k. In particular, the accuracy of a balance design (ni = n, i = 1, 2, ..., k) for estimating p is compared with the accuracy of an unbalanced "natural" design, in which the ni are sampled at random from family size distributions that tend to occur in practice. It is found for two different estimators of p that the balanced design is usually preferable, but only to a small degree if the number of families sampled is greater than 50.

Epidemiologic Methods↗
PubMed1982

Phase I clinical trial and pharmacokinetics of 4'-carboxyphthalato(1,2-diaminocyclohexane)platinum(II).

4'-Carboxyphthalato(1,2-diaminocyclohexane)platinum(II) is a new, second generation platinum analog which had demonstrated in vitro activity in L1210 cell lines resistant to cisplatin and had less nephrotoxicity than did cisplatin in preclinical animal testing. A Phase I trial with this agent has been performed in 45 patients with advanced refractory cancers. Nine dosage levels, ranging from 40 to 800 mg/sq m, were studied. Major toxicities seen were myelosuppression, nephrotoxicity (which was generally mild), nausea and vomiting (which was quantitatively less than that seen with cis-platin), allergic reactions, and a peripheral neuropathy. The dose-limiting toxicity was thrombocytopenia. Pharmacokinetics performed at three dosage levels indicates that 4'-carboxyphthalato-(1,2-diaminocyclohexane)platinum(II) has a long t1/2 of 20 to 30 hr (total platinum) and is only partially excreted in the urine and that a high proportion of the drug is nonfilterable within 30 to 60 min of administration. Therapeutic responses were seen in nasopharyngeal carcinoma, adenocarcinoma of the cervix, and lung and gastric cancer. As a starting dose for Phase II studies, which are planned for patients with ovarian, testicular, lung, gastric, and esophageal cancers, 640 mg/sq m given every 3 to 4 weeks is recommended.

Creatinine↗
PubMed1981

A comparison of estrogen use by women with endometrial cancer, gynecologic disorders, and other illnesses.

Exogenous estrogen use was determined by interview in 206 endometrial cancer patients, 191 women with nonmalignant gynecologic disorders, and 199 women with other illnesses. Separate comparisons of these patients with gynecologic and other illness control subjects provided estimates of the risk of endometrial cancer among estrogen users, adjusted for the effects of confounding variables, of 1.5 (95% confidence limits 0.9 and 2.7) and 4.8 (2.7 and 8.4), respectively. In both comparisons, risk increased with increasing duration of use; regardless of duration of use, risks were higher among users of estrogen within 12 months of diagnosis than among past users. The effects of bias, including surveillance bias, on the results were considered and it was concluded that the true risk was not less than the case/gynecologic control estimate and was likely to approach the case/other control estimate.

Adenocarcinoma↗
PubMed1981

Effect of ingestion of meat on plasma cholesterol of vegetarians.

In a controlled trial, 21 strict vegetarians were studied prospectively for eight weeks: a two-week control period of the usual vegetarian diet was followed by four weeks, during which 250 g of beef was added isocalorically to the daily vegetarian diet and then by two weeks of the control diet. Plasma high-density lipoprotein-cholesterol did not change during the study, whereas plasma total cholesterol rose significantly by 19% at the end of the meat-eating period. Systolic blood pressure (BP) increased significantly during the meat eating by 3% over control values, whereas diastolic BP showed no major changes. Plasma renin activity, prostaglandin A and E levels, and urinary kallikrein, norepinephrine, and epinephrine excretions were within normal limits and did not change notably throughout the trial. The study suggests an adverse effect of consumption of beef on plasma lipid and BP levels.

Adult↗
PubMed1981

The effect of different treadmill speeds on the variability of VO2 max in children.

Eight boys aged 10-12 years performed three tests on each of three treadmill protocols. Each test was a continuous, progressively graded performance to exhaustion, but protocols differed in speed--(walk: 90 m . min-1, jog: 110 m . min-1, run: 130 m . min-1). The walk protocol was found inappropriate for VO2 max determination in children. Compared to the faster speeds, the walk test elicited a lower VO2 at exhaustion, and had lower reliability (0.56) and a high coefficient of variation (8%). For the Vo2 at exhaustion on the jog and run protocols the coefficient of variation was 3-5% and the reliability coefficient averaged 0.90, comparable to values seen for repeated trials in adults. The usually accepted VO2 max criterion of a plateau of VO2 with increasing work levels was inappropriate for use with children. Attempts to derive plateau criteria suitable for use with children proved unsuccessful. Plateau criteria may be difficult to achieve with children in light of their apparently weaker glycolytic energy capacity. Nevertheless, the highest VO2 measured at jog or run speeds has a consistency similar to that found for Vo2 max measurement in adults.

Child↗
PubMed1981

A multivariate analysis of family data.

The authors describe the application of multivariate analysis to the problem of estimating intra-family correlations and testing them for statistical significance. This is illustrated by a re-analysis of survey data collected by Miall and Oldham (Clin Sci 1958;17:459-87) on the familial aggregation of blood pressure. The multivariate analysis provides collective tests of significance for parent-child and child-child correlations based on likelihood ratio theory, and maximum likelihood estimates for individual intra-family correlations.

Blood Pressure↗
PubMed1980

Oestrogen use and survival in endometrial cancer.

Of 860 women with endometrial cancer registered in a regional cancer treatment centre, 259 (30%) gave a history of oestrogen use for 6 months or more at some time before diagnosis, and 568 (66%) were non-users. OEstrogen use was associated with younger age, earlier stage, lower grade of tumour, less common myometrial invasion, and preferred treatment including radiation and hysterectomy. The 5-year survival of oestrogen users was 92 +/- 2% compared with 68 +/- 2% for non-users. Further analysis controlling for differences in the distribution of the variables associated with survival showed that for women who have endometrial cancer, the risk of any death for non-users is approximately 2-7 times greater than for oestrogen users, and the risk of death from endometrial cancer is 5.4 times greater for non-users. A history of oestrogen use is not associated with superior survival of women who have poorly differentiated tumours or myometrial invasion.

Adult↗
PubMed1980

Trimethoprim-sulfamethoxazole compared with ampicillin in the treatment of acute otitis media.

We treated 132 children with acute otitis media in a randomized trial comparing trimethoprim-sulfamethoxazole and ampicillin. The antibacterial efficacy of the drugs was assessed primarly from the results of cultures of middle ear aspirates obtained during or after the course of therapy; persistent, recurrent, and new infections of the middle ear were documented in both groups of patients but did not differ significantly. Both drug regimens were well accepted by the patients and were not associated with serious side effects or toxicity. TMP-SMZ is an effective alternate to AMP or to other accepted regimens for initial treatment of acute otitis media.

Acute Disease↗
PubMed1980

The estimation of intraclass correlation in the analysis of family data.

The maximum likelihood estimator of the intraclass correlation coefficient rho in samples of unequal size from a multivariate normal distribution has been derived and compared to several other estimators, using Monte Carlo simulation. It is recommended that maximum likelihood be used if no prior knowledge concerning the value of rho is thought to be high. Fow low to moderate values of rho it is recommended that the analysis of variance estimator be used, with those families having only one member deleted from the analysis.

Analysis of Variance↗
PubMed1979

Persistence of middle-ear effusion after acute otitis media in children.

We observed the frequent occurrence of persistent middle-ear effusion in children with acute otitis media and followed them according to standard procedures for otologic diagnosis. We performed a life-table analysis to identify risk factors for such persistent disease. Sixty-two patients were free of middle-ear effusion at one or more clinic visits two to 13 weeks after presentation and were considered cured; 45 had effusion at all clinic visits during this period and were defined as having persistent effusion. The life-table analysis showed that the relative risk for persistence was 3.8 times higher in children less than 24 months of age as compared with children 24 months of age or older (P less than 0.001) and that this risk was 2.8 times greater for white as compared with black children (P less than 0.01). Other factors examined were not identified as significant risk factors. Persistent middle-ear effusion may be associated with impaired hearing and appears to be the most important sequela of otitis media.

Acute Disease↗