I. L. Rouse

The Causes of Malignant Melanoma: Results from the West Australian Lions Melanoma Research Project

In Australia malignant melanoma ranks forth among cancers as a cause of morbidity and premature death (Armstrong 1985). For this reason, and because the State of Western Australia has one of the highest incidence rates of melanoma in the world (Holman et al. 1980), we undertook a multidisciplinary research program embracing the epidemiology, histopathology, and clinical management of melanoma. A major component of our research was a population-based case-control study in which constitutional traits, sunlight exposure, hormones, diet and other possible causal factors were evaluated. We have already published several reports of the results relating to particular subject areas (Holman and Armstrong 1983, 1984 a, b; Holman et al. 1984 b, 1985; English et al. 1985). In this report we aim to bring together in summary form the key results of the project to date and to present new data on diet and other factors.

A CONTROLLED TRIAL OF NURSE COUNSELLING ON LIFESTYLE CHANGE FOR HYPERTENSIVES TREATED IN GENERAL PRACTICE: PRELIMINARY RESULTS

1. We assessed whether a lifestyle modification programme implemented by nurse counsellors in a general practice setting would improve blood pressure (BP) control in treated hypertensive patients.

Relationship of plasma HDL-Cholesterol to testosterone, estradiol, and sex-hormone-binding globulin levels in men and women

The significance of sex hormone levels in determining variation in high-density lipoprotein cholesterol (HDL-C) concentrations was studied in healthy Seventh Day Adventists (vegetarians) and Mormons. These groups were selected to avoid the confounding effects of alcohol consumption and cigarette smoking on HDL-C concentrations. Multivariate analysis showed that testosterone has a strong negative association with HDL-C in men (t = 3.99, P less than 0.001) and women (t = 2.04, P less than 0.05) when controlled for other variables including the concentration of sex-hormone-binding globulin (SHBG). Sex-hormone-binding globulin showed an independent positive association with HDL-C in men (P less than 0.001) and women (P less than 0.001). We postulate that the sex hormones affect HDL-C levels by regulating the activities of two important enzymes involved in the production and catabolism of HDL, namely, lipoprotein lipase and hepatic endothelial lipase. Other factors contributing independently to variation in HDL-C levels in this study were, in men, age and triglyceride, and in women, apoprotein-HDL, triglyceride, systolic blood pressure, heart rate, body mass index, and triceps skinfold thickness. Plasma estradiol concentrations were not significantly associated in either sex.

Leukocyte and platelet function and eicosanoid production in subjects with hypercholesterolaemia

A group of 22 subjects with type IIA hypercholesterolaemia (mean serum cholesterol = 8.3 +/- 0.3 mmol/l) were sex, age and weight matched with 22 control subjects (mean serum cholesterol = 4.5 +/- 0.1 mmol/l). Diastolic blood pressure was significantly higher in hypercholesterolaemic subjects (79.2 +/- 1.4 mm Hg) than in control subjects (71.9 +/- 1.4 mm Hg). While the high cholesterol group had 52% greater thromboxane production in clotted whole blood than controls this difference was not significant, and the platelet aggregation and serotonin secretion response to doses of collagen, ADP and arachidonic acid were similar between the 2 groups. Polymorphonuclear leukocyte (PMN) chemiluminescence (used as a measure of reactive oxygen species production) in response to low doses of the chemotactic-peptide FMLP and opsonized zymosan was significantly greater in high cholesterol subjects compared to their matched controls. The production of platelet activating factor (PAF) by calcium ionophore (2.5 micrograms) stimulated PMN isolated from hypercholesterolaemic subjects (11.5 +/- 1.4 ng/10(6) cells) was significantly greater than PAF production by cells from the control group (8.3 +/- 1.0 ng/10(6) cells). Leukotriene B4 release by PMN in response to calcium ionophore did not differ between the 2 groups. These data suggest a degree of leukocyte activation in hypercholesterolaemic subjects compared to controls with normal cholesterol. In addition, plasma levels of lyso-PAF were higher in high cholesterol subjects (317 +/- 21 ng/ml) compared to their matched controls (271 +/- 18 ng/ml) perhaps indicating increased plasma acetylhydrolase activity in subjects with raised cholesterol levels. Recently described biological activity for lyso PAF suggests a possible role for this substance in atherogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Vegetarian diet and blood pressure levels: incidental or causal association?

Evidence that nutrients other than the major cations may influence blood pressure levels stems from studies of acculturated vegetarians and from randomized controlled dietary trials. Earlier studies of vegetarians focused on religious groups and on vegans, making it difficult to know whether their lower blood pressures were due to diet per se or to other aspects of lifestyle. Seventh-day Adventist vegetarians showed significantly less hypertension and lower blood pressures compared with Mormon omnivores, effects which were independent of differences in obesity and not due to altered sodium intake. Subsequently, controlled dietary intervention studies in healthy normotensive omnivores provided more direct evidence for a blood pressure-lowering effect of a lactoovovegetarian diet with reversible changes of 5-6 mm Hg systolic and 2-3 mm Hg diastolic occurring over 6-wk periods. Similar dietary effects in mild hypertensive subjects provides impetus for identifying the responsible nutrients.

A RANDOMIZED CONTROLLED TRIAL OF THE EFFECT OF ALCOHOL CONSUMPTION ON BLOOD PRESSURE

1. Forty‐six healthy normotensive male drinkers participated in a randomized, controlled, crossover trial to study the effects of varying alcohol intake on blood pressure.

ALCOHOL AND BLOOD PRESSURE IN A WORKING POPULATION

1. The association between alcohol consumption and blood pressure was studied in 491 Government employees. The men, aged 21–45 years, volunteered to complete a health questionnaire and submitted to standardized measurements of blood pressure, heart rate and body size.

Vegetarian diet and blood pressure.

There is now convincing evidence from epidemiological studies and randomized controlled trials that adoption of an ovo-lacto vegetarian diet leads to blood pressure reduction in both normotensive and

The effect of hormones on glucocorticoid binding capacity of rat liver cytosol.

Abstract The relationship between the glucocorticoid binding capacity of rat liver cytosol and the activity of tyrosine aminotransferase has been studied in adrenalectomized male rats. Bilateral adrenalectomy of male rats caused an increase within 3 days in the level of specific dexamethasone binding of liver cytosol accompanied by a rapid decrease in tyrosine aminotransferase activity. Known inducers of tyrosine aminotransferase were administered in vivo to test their effect on dexamethasone binding capacity, in order to determine whether the induction was by an indirect mechanism involving an increase in glucocorticoid binding capacity. Insulin, adrenalin, glucagon, dibutyryl cyclic AMP and oestradiol caused a significant increase in the activity of the enzyme, with no change in the specific dexamethasone binding. Tetracosactrin, a synthetic analogue of ACTH, had no effect on either parameter. It was concluded that the induction of tyrosine aminotransferase by the compounds tested was not mediated by an increase in glucocorticoid receptor activity.