Hypertension, antihypertensive medication and risk of renal carcinoma in California Seventh-Day Adventists

A longitudinal study of 34 198 non-Hispanic white California Seventh-day Adventists identified incident cases of renal carcinoma over six years of follow-up. The use of antihypertensive medications and self-reported hypertension had estimated age-sex adjusted incidence rate ratios of 4.51 and 2.90 respectively. These were relatively unchanged by stratifying on additional variables that may have been confounders. Cases diagnosed later during the follow-up period had the strongest association with hypertension, making the alternative explanation that the cancer may have caused the hypertension less likely. Being married in 1976 (amongst females at least) was also associated with a marked elevation of risk. Point estimates of effect suggested that frequent (greater than or equal to 3 week) consumption of fruit (RR = 0.21) and salad vegetables (RR = 0.34) may be protective for this cancer, although the 95% confidence interval did not quite exclude the null value.     

Velocity of mammalian skeletal muscle contraction as a function of fiber type, activation, initial length and temperature.

Multiple stepwise regression analyses techniques were applied to develop modifications of the Hill force-velocity equation. Specifically, predictive models of the Hill a coefficient, the Hill b coefficient, and isometric strength P0 were developed for the following set of variables: the fraction of slow-twitch fibers (X), the recruitment magnitude (A), the initial muscle length (L), and the muscle temperature (T). Results indicate that the Hill a and Hill b coefficients and isometric strength P0 can be predicted with a high degree of accuracy. The utility of the equation is that it would allow development of a computer program to control the velocity of contraction of muscles with differing fiber compositions and lengths such as are found in the leg.     

Induction of ovulation with gonadotrophin-releasing hormone--life-table analysis of 50 courses of treatment

Ovulation induction by means of the pulsatile subcutaneous administration of gonadotrophin-releasing hormone by way of an infusion pump is described. The clinical outcome in 50 courses of treatment, which totalled 116 treatment cycles, was analysed and was compared with the pregnancy rates that were obtained with the administration of human pituitary gonadotrophins. We found that the pregnancy rates for these two treatments were similar. We also have shown that for those women who ovulated as a result of such treatment the conception rates were similar to those in ovulatory women who had discontinued contraception. We conclude that gonadotrophin-releasing hormone has an important place among the ovulation-induction agents.     

The development of post-traumatic cyst-like lesions in bone

Cyst-like lesions in the radius and tibia were observed in two children as a post-fracture event. The pathogenesis of these lesions is discussed. Cut sections from anatomic specimens display extensive hemorrhage in subperiosteal as well as endosteal and trabecular bone. Cysts arising from hemorrhagic resorption in various locales may explain the occasional atypical appearance of these lesions.     

Comparative metabolism of BHA, BHT and other phenolic antioxidants and its toxicological relevance

Following oral administration, butylated hydroxyanisole (BHA) is absorbed and rapidly excreted by the rat, rabbit and man, with little evidence of long-term tissue storage. The major metabolic pathways for BHA are conjugation (phase 2) reactions, oxidative metabolism (O-demethylation) being relatively unimportant. In the dog, the extent of absorption and urinary excretion is less, and oxidative metabolism is more important than in other species. In contrast, butylated hydroxytoluene (BHT) is cleared less rapidly from most species, enterohepatic circulation being partly responsible for the delay. Tissue accumulation is also greater for BHT than for BHA. Oxidative metabolism (phase 1 reactions) mediated by the microsomal monooxygenase system is the major route for BHT degradation; oxidation of the ring methyl group predominates in the rat, rabbit and monkey, and oxidation of the tert-butyl groups in man. Gallates and 2-tert-butylhydroquinone are mainly metabolized by non-oxidative pathways (methylation or conjugation with sulphate and glucuronic acid). The different biological properties of these compounds may be related to the differences in their absorption and metabolic disposition. Thus, whereas BHT, which is metabolized by oxidation reactions, is an inducer of the microsomal mono-oxygenase system, the other phenolic antioxidants, including BHA, are only weak inducers.