Niels Dyhr Christensen

Multivariate statistical analysis of organ weights in toxicity studies.

Toxicity studies with drugs in animals are performed to establish the toxicity profile including the no-toxic-effect-level in the animals. One of the responses used in the search for effects is organ weight. Since organ weight is related to body weight of the animal, the analysis of organ weight has to be adjusted. A traditional analysis of covariance with body weight as covariate is not always appropriate since the body weight itself can be affected by the test compound. Hence, a multivariate analysis of variance is suggested, where the correlation between organ weight and body weight is taken into account in testing an overall treatment effect. Two dimensional plots of the contour curves are used to visualize the treatment effect on organ weight and body weight simultaneously. The test procedure suggested for comparing differences between control and treated groups of animals is: start by testing hypotheses of equality of covariance matrices for the different treatment groups and then, depending on the results from the first test, test equality of the mean vectors.

Benign Prostatic Hypertrophy

IN BRIEF: Benign prostatic hypertrophy is one of the common complaints of older men who visit their primary care physicians. Nonoperative therapy, such as drug therapy or lifestyle modification, is aimed primarily at reducing bothersome lower urinary tract symptoms and preventing serious morbidity such as urinary retention and renal function impairment. As more men reach advanced age, it becomes crucial for the primary care physician to be aware of the epidemiology, pathophysiology, natural history, clinical presentation, and therapeutic modalities available for the treatment of clinically significant cases.