Biomedical subjects

T R Stiger

Publications and source records attributed to T R Stiger.

5 recordsLinked to original sources

PubMed1999

Testing proportionality in the proportional odds model fitted with GEE.

Generalized estimating equations (GEE) methodology as proposed by Liang and Zeger has received widespread use in the analysis of correlated binary data. Miller et al. and Lipsitz et al. extended GEE to correlated nominal and ordinal categorical data; in particular, they used GEE for fitting McCullagh's proportional odds model. In this paper, we consider robust (that is, empirically corrected) and model-based versions of both a score test and a Wald test for assessing the assumption of proportional odds in the proportional odds model fitted with GEE. The Wald test is based on fitting separate multiple logistic regression models for each dichotomization of the response variable, whereas the score test requires fitting just the proportional odds model. We evaluate the proposed tests in small to moderate samples by simulating data from a series of simple models. We illustrate the use of the tests on three data sets from medical studies.

Adult↗

PubMed1986

Flurbiprofen versus naproxen in the treatment of rheumatoid arthritis.

The efficacy and safety of flurbiprofen (Ansaid, Upjohn), 100 mg twice daily, were compared with those of naproxen, 250 mg twice daily, in a six-week, double-blind, randomized study involving 133 patients with rheumatoid arthritis. Patients completing the six-week treatment phase were then treated with flurbiprofen, 100 mg twice daily, during a six-week open-label phase. In the double-blind phase, both treatment groups showed improvement from baseline and, in general, the arthritic condition of all patients was significantly less severe while receiving treatment. In the open-label phase, the patients in whom therapy was switched from naproxen to flurbiprofen reported greater improvement compared with baseline than they did at the end of the double-blind phase. Statistically significant differences between medication groups were few. At weeks four and six, grip strength for the naproxen group increased from baseline by a marginal amount compared with the flurbiprofen group. Global evaluations of disease improvement by patients and physicians and proximal interphalangeal joint size showed trends in favor of flurbiprofen. In the double-blind phase, 29.4 percent of flurbiprofen-treated patients (n = 20) and 23.1 percent of naproxen-treated patients (n = 15) experienced side effects, most of which were gastrointestinal in origin. In the open-label phase, 81.0 percent of the patients (n = 87) satisfactorily completed the six weeks of flurbiprofen treatment. Based on this study, 100 mg of flurbiprofen administered twice daily was as effective as 250 mg of naproxen twice daily in the treatment of rheumatoid arthritis.

Adolescent↗

PubMed1985

Supra-additive toxic interaction of nicotine with antihistamines, and enhancement by the proconvulsant pentylenetetrazole.

Antihistamines are being increasingly administered in combination with various other agents, with adverse drug reactions the frequent result. The present study consisted of two experiments. Experiment 1 examined the toxicological response of rats to nicotine tartrate (0.0, 2.0, 4.0, and 8.0 mg/kg) in combination with either of two H1-histamine receptor antagonists, the ethylene diamine tripelennamine HCl (0.0, 16.0, 32.0, and 64.0 mg/kg) or the aminoethyl ether diphenhydramine HCl (0.0, 32.0, 64.0, and 96.0 mg/kg). Adult female rats received intraperitoneal injections when housed 12 per cage and toxicological response (number dead per group) was assessed 24 hours post-treatment. The results showed that over the dose ranges employed, and when given alone, nicotine was completely non-lethal, tripelennamine was virtually non-lethal and diphenhydramine was toxic only at the highest dose (5 of 12, at 96.0 mg/kg). However, when nicotine and the antihistamines were delivered in combinations, the toxicological response was markedly altered. Tripelennamine in combination with nicotine yielded supra-additive interaction, with the degree of potentiation being a simple linear function of nicotine within each dose of tripelennamine. The interaction between nicotine and diphenhydramine was more complicated, with certain dose combinations yielding supra-additivity, yet with others yielding antagonism. It was suggested that seizure-precipitated cardiopulmonary collapse was the immediate cause of death, plausibly mediated by central mechanisms. As such, Experiment 2 examined the influence of adding the proconvulsant pentylenetetrazole (PTZ) (0.0, 10.0, and 20.0 mg/kg) to nicotine (0.0, 2.0, 4.0, and 8.0 mg/kg)-tripelennamine (0.0 and 32.0 mg/kg) combination treatments. Effects were assessed both at 1.0 and 24.0 hours post-injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Comparative efficacy of once a day diflorasone diacetate and twice a day betamethasone valerate ointment applications in eczematous dermatitis.

The efficacy of once a day applications of 0.05% diflorasone diacetate ointment and twice a day applications of 0.1% betamethasone valerate ointment was compared in 70 patients with eczematous dermatitis. Altogether 32 patients completed the 3-week study. Fourteen patients in the diflorasone group and 6 on betamethasone left the study earlier because of total (100%) improvement of lesions. Eight patients left because of unsatisfactory progress and 6 because of personal reasons. There were only two noticeable differences observed between treatment groups. At Week 2, the diflorasone diacetate group improved significantly more than the betamethasone valerate group with respect to pruritus. At Week 3, this difference in the improvement of pruritus was marginally significant in favour of diflorasone diacetate. Excluding the complications due to a secondary infection, no adverse reactions were recorded in the diflorasone diacetate-treated patients; 1 betamethasone valerate-treated patient developed telangiectasia. The once a day applications of diflorasone diacetate not only proved to be slightly more efficacious than the twice a day applications of betamethasone valerate, but also provided the advantages of patient convenience and compliance.

Adolescent↗

PubMed1983

Parachloroamphetamine toxicity in mice: influence of body weight, sex and dose.

Five doses of d,l-para-chloroamphetamine (0.0, 15,0, 30.0, 45.0 and 60.0 mg/kg) were used to challenge 10 groups of 16 male and 10 groups of 16 female CF-1 mice weighing either 16 to 25 g or 40 to 55 g. Twenty-four hours after intraperitoneal injection, rates of lethal toxicity were assessed. Effects for body weight and dose were found. In addition, a sex by dose interaction was demonstrated. It was hypothesized that the influence of weight might be related to thermoregulatory processes, since as weight rises, surface-to-volume ratios decline, and with them the efficiency of heat exchange. Caution is suggested in the interpretation of ontological studies of drug response.

Amphetamines↗