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To examine the effects of dietary isoflavone supplementation with an extract from red clover on cognitive function in postmenopausal women.Thirty postmenopausal women aged greater than 60 years received either two tablets of an extract of aglycone isoflavones from red clover (each containing formononetin 25 mg, biochanin 2.5 mg and less than 1 mg of daidzein and genistein) for 6 months in a randomized, controlled clinical trial. Cognitive function tests were performed at baseline and at the end of isoflavone or placebo therapy.Isoflavone supplementation was associated with an apparent improvement in block design (a test of visual-spatial intelligence) compared to placebo (isoflavone +12%, placebo -3%; p = 0.03), no improvement in verbal memory compared to an improvement on placebo (isoflavone +1%, placebo +29%; p = 0.023) and a deterioration in digit recall compared to placebo (isoflavone -6%, placebo +12%; p = 0.029). However, these findings were not statistically significant when corrections were made for potential chance findings due to multiple comparisons.Isoflavone supplementation does not appear to have major short-term effects on cognitive function in postmenopausal women. However, further clinical trials are required to determine whether small effects or long-term effects on cognitive function occur during isoflavone supplementation.

Objectives: To assess the acceptability of the delivery of an isoflavone supplementation in the form of a powdered drink, and whether the supplementation of dietary isoflavones in this manner decreased the incidence of menopausal flushes. The secondary aims included assessment of other symptoms or parameters of estrogen deficiency and responses to isoflavones. Methods: A randomized, double-blind, placebo-controlled, parallel-group trial comprising 24 postmenopausal women with symptoms of estrogen deficiency was performed over a 12-week period. The women were randomized to receive a dietary beverage containing isoflavones or an isoflavone-free, isocaloric placebo preparation. Results: Although there was a high compliance rate among individual patients, there was a 25% withdrawal rate from the study in the active group. The incidence of complaints of bad taste tended to be higher in the active group (p = 0.07), and the total number of adverse events was significantly higher in this group (p < 0.001). There ...

We have previously reported a strong positive association between average day time and nighttime heart rate measured during 24 hour ambulatory blood pressure monitoring and usual alcohol intake.1 Acute alcohol consumption has been previously described to reduce ECG indices of vagal activity, and men who are severely dependent on alcohol have been reported to have significantly lower indices of cardiac vagal nerve activity than normal volunteers.2–5 We performed 24 hour ambulatory ECG monitoring and power spectral analysis of heart rate variability in apparently healthy middle aged men to examine the association between alcohol consumption, heart rate, and indices of heart rate variability. Twenty eight men aged 50 (9) years (range 33–68 years) who were free from clinically apparent alcohol related or cardiovascular diseases and receiving no medication were selected from volunteers responding to an advertisement in a local newspaper. The subjects’ blood pressures (128 (12)/75 (9) mm Hg), heart rate (72 (9) beats/min), body weight, and height were measured and their demographic details recorded. A detailed alcohol consumption history was taken by an experienced alcohol and other drugs nurse counsellor (JR). The information obtained included the duration that they had been consuming their current alcohol intake, the days of the week that they usually drank, and the amount of alcohol consumed …

Ten normal volunteers consumed 80 g of ethanol per day or abstained from ethanol for 4 consecutive days prior to measurements of blood pressure, heart rate, vascular responsiveness to noradrenaline (NA) and angiotensin II (AII) infusions and sympathetic responsiveness to isometric handgrip exercise in an open, random order, crossed study. Supine systolic and diastolic pressures and heart rates, and erect systolic pressures rose significantly following ethanol. Vascular responsiveness to NA infusions was reduced in all subjects following ethanol, while responses to AII infusions did not show a consistent pattern of change. Plasma renin activity, plasma NA and adrenaline concentrations, and concentrations of the NA metabolite 3,4 dihydroxyphenylethylene glycol (DHPG) did not significantly differ following ethanol and control treatments. The rise in plasma NA following 2 min isometric handgrip at 50% of maximal effort was greater following ethanol (0.24 +/- 0.21 nM) than control (0.12 +/- 0.10 nM) but the difference did not reach statistical significance. The pressor effect of regular ethanol consumption and the reduced vascular reactivity to NA may both be the result of an increase in sympathetic activity that was not large enough to measurably alter resting plasma NA concentrations.

In chronic cardiac failure, various neurohumoral mechanisms are activated to sustain blood volume, blood pressure, and organ perfusion. Using the coronary artery ligation model of heart failure in the rat, we have measured changes in vasoactive hormone secretion and related these changes to salt and water status during a 1-month period. When compared with controls, rats with infarction had a marked rise in plasma atrial natriuretic peptide (294 +/- 59 vs. 79 +/- 10 pg/ml, p less than 0.001) although there was no increase in total exchangeable body sodium. Plasma renin activity and plasma aldosterone concentrations were the same for both rats with infarction and controls. Similarly, there were no significant differences in plasma arginine vasopressin, plasma osmolality, or plasma sodium concentration in rats with infarction. Ventricular norepinephrine levels were reduced in animals with infarction (p less than 0.01). Plasma atrial natriuretic peptide levels were raised in this model of chronic left ventricular failure. However, there was no salt retention and little stimulation of the renin-angiotensin-aldosterone system or vasopressin. The results suggest that high circulating atrial natriuretic peptide levels may prevent or limit salt and water retention, either directly or indirectly, by inhibiting the renin-angiotensin-aldosterone system.

1. An improved approach for the determination of plasma [3H]noradrenaline ([3H]NA) kinetics in man is described, incorporating the extraction of plasma [3H]catechols on alumina and separation of [3H]NA from [3H]dihydroxymetabolites by high-performance liquid chromatography (HPLC). 2. After a 30 min intravenous infusion, [3H]NA accounted for 57.2 ± 13.2% of the radioactivity recovered by the procedure, while the dihydroxymetabolites 3,4-[3H]dihydroxyphenylethylene glycol ([3H]DHPG) and 3,4-[3H]dihydroxymandelic acid ([3H]DOMA) accounted for 32.3 ± 11.5% and 4.9 ± 6.0% respectively. After 90 min of constant infusion the proportion due to [3H]NA fell to 44.4 ± 10.4%, while that due to [3H]DHPG rose to 45.9 ± 9.5% because of an increase in the amount of [3H]DHPG at the later time. 3. Plasma [3H]NA radioactivity rose rapidly during the constant infusion and usually reached a plateau by 30 min. However, in individual subjects large variations in plasma [3H]NA radioactivity occurred during the course of the infusion, implying rapid and variable changes in plasma [3H]NA clearance. 4. The inclusion of a step to separate [3H]NA from [3H]dihydroxymetabolites is necessary if the aim is to determine plasma [3H]NA kinetics, as a large proportion of the radioactivity recovered from plasma on alumina is due to the presence of these metabolites.

Plasma levels of norepinephrine (NE) and the NE metabolite 3,4-dihydroxyphenylethylene glycol (DHPG) were measured simultaneously following sympathetic activation induced by standing, cold pressor testing and bicycle exercise at progressively increasing workloads in normal volunteers. Free DHPG and NE levels both increased with sympathetic activation, but free NE levels were a more sensitive index of change. In addition, plasma free NE levels more closely reflected the fall in heart rate following exercise than free DHPG. In contrast to free levels, conjugated DHPG and NE levels did not change significantly after exercise. Supine resting free DHPG/ NE ratios were always greater than 2·0, but fell progressively with increasing sympathetic activation because of a proportionately greater rise in NE than DHPG. The simultaneous measurement of plasma free DHPG and NE does not offer advantages over free NE levels as an index of sympathetic activity in man, but may be of use in the diagnosis of pheochromocytoma and in studies of NE metabolism.

Normotensive male volunteers (n = 8) either abstained from ethanol for 4 days or consumed 66 g of ethanol per day in an open, crossed, random order study. Mean arterial pressures rose by an average of 5.4 mmHg following the ethanol phase of the study (P less than 0.001). Plasma noradrenaline (NA) concentration was higher during ethanol ingestion (P less than 0.01), principally because of a significant reduction in NA clearance of -1.51 l min-1 m-2 (P less than 0.05). In contrast, NA spillover or release rates did not significantly differ between the two study periods. Total plasma calcium levels were significantly lower (P less than 0.05) following the ethanol compared to the control period. These data do not appear to support the proposition that regular alcohol consumption raises blood pressure by producing a generalised increase in sympathetic activity.