The effect of “selective” β-adrenoceptor blocking drugs on the myocardial circulation

1. A comparison has been made of the effects of a relatively specific beta(1)-adrenoceptor blocking drug (practolol) and a relatively specific beta(2)-adrenoceptor blocking drug (butoxamine) on myocardial and general haemodynamics in anaesthetized cats.2. Practolol, in a dose (10 mg/kg, intravenously) which had little effect on arterial pressure, heart rate, myocardial blood flow or myocardial vascular resistance, markedly reduced the effects of isoprenaline infusions on heart rate, aortic dp/dt, myocardial blood flow, vascular resistance and metabolic heat production, and the cardiac effort index. Isoprenaline induced vasodepression was unaffected.3. Butoxamine (5 mg/kg, intravenously) decreased heart rate, aortic dp/dt, the cardiac effort index and myocardial blood flow and increased myocardial vascular resistance. This is taken as further evidence for the existence of beta(2)-adrenoceptors in the myocardial microcirculation.4. After butoxamine, the effects of isoprenaline on myocardial blood flow, myocardial vascular resistance and heart rate were unaffected but the peripheral vasodilator effect was abolished. The effects on aortic dp/dt and the cardiac effort index were potentiated.5. It is concluded that the effect of isoprenaline in increasing myocardial blood flow is due predominantly to increased cardiac work and oxygen consumption and that practolol, since it has little direct effect on myocardial blood flow yet abolishes the cardiac stimulant and oxygen wasting effects of released catecholamines, has properties which indicate that it should be an effective and safe anti-anginal drug.     

Comparability of dietary patterns assessed by multiple dietary assessment methods: results from the 1946 British Birth Cohort

OBJECTIVE: The aim of this study is to evaluate the consistency of dietary patterns assessed through the use of a dietary recall and a 5-day food diary. DESIGN: Participants (n = 2265) of a longitudinal study of health and development completed 48-h dietary recall at interview, followed by a 5-day food diary and with the 24 h immediately preceding the interview analysed separately as a 24-h recall. Mean intakes of foods and nutrients were calculated and dietary patterns were assessed using exploratory factor analysis, using the method of principal components. Paired t-tests and correlation coefficients were used to compare the three dietary assessment methods. RESULTS: Five distinct dietary patterns were identified using the food diary and the 48-h recall but were less consistent on the 24-h recall. Correlations between factor scores on the 48-h recall and the food diary (r = 0.13-0.67) were higher than those between the 24-h recall and food diary (r = -0.01-0.59). The recall methods were effective at ranking subjects according to food and nutrient intakes, with the 48-h recall and food diary showing higher correlations in both males and females. CONCLUSIONS: This study indicates that a 48-h recall effectively characterises dietary patterns in British adults when compared to a food diary and ranks participants appropriately with respect to most nutrients and foods and is superior to a single 24-h recall. These results have implications for longitudinal studies where maximising response rates to repeat dietary assessment tools is essential.     

Supplement use is associated with health status and health-related behaviors in the 1946 British birth cohort

Use of dietary supplements may be one of a number of health-related behaviors that cluster together. The current study investigated the underlying diet, health-related characteristics, and behaviors of users and nonusers of dietary supplements in a longitudinal study of health. Participants (n = 1776) completed a 5-d food diary including information on dietary supplement use (vitamins, minerals, and nutraceuticals) at age 53 y. Sociodemographic information and data on smoking, alcohol, and physical activity were obtained along with anthropometric measurements, blood pressure, and a blood sample (nonfasting subjects). A significantly greater percentage of women reported supplement use compared with men (45.1 vs. 25.2%). Supplement use was associated with lower BMI, lower waist circumference, higher plasma folate and plasma vitamin B-12 concentrations, nonsmoking, participation in physical activity, and nonmanual social class in women and with plasma folate concentrations and participation in physical activity in men. Nonsupplement users tended to be nonconsumers of breakfast cereals, fruit, fruit juice, yogurt, oily fish, and olive oil and had lower dietary intakes of potassium, magnesium, phosphorus, iron, and vitamin C even after adjustment for sociodemographic and behavioral factors. Overall, supplement users tended to differ from nonsupplement users on a range of health-related behaviors and health status indicators, although there were fewer significant associations in men. Similarly, dietary supplements users tended to have underlying diets that, were healthier and those taking supplements may be the least likely to need them. These results support the notion of a clustering of healthy behaviors and cardiovascular risk factors, particularly for women.     

Chyluria

A case of chyluria in a young white male is presented. Lymphangiogram, CT, and digital vascular imaging findings are presented along with a brief review of the literature.     

KCL CONTRACTIONS IN THE RAT INTACT AND BISECTED VAS DEFERENS: CONTRIBUTION OF ENDOGENOUS NORADRENALINE RELEASE

1 KCl produced a biphasic contraction in the intact rat vas deferens. Both components were larger and the initial rapid phasic component was faster in the prostatic portion than the epididymal portion. In some experiments the epididymal phasic response was a single slow contraction, while in others it had a mixture of fast and slow responses. 2 Phentolamine reduced the phasic response but not the tonic response of the intact vas deferens. This effect was not observed after denervation produced by chronic guanethidine treatment. 3 Both phases of the response to KC1 160 mmol/1 were substantially reduced by phentolamine in the epididymal portion. In the prostatic portion phentolamine produced only slight inhibition of the phasic component and had no effect on the tonic component. 4 Isoprenaline had no effect on the response to KC1160 mmol/1 but reduced both phases of the response to KC150 mmol/1. This effect was antagonized by propranolol. 5 It is concluded that part of the phasic component of the response to KC1 in the rat vas deferens is due to the release of noradrenaline from intramural nerves.     

Alpha1-antitrypsin as a risk for infant and adult respiratory outcomes in a national birth cohort

Reduced alpha1-antitrypsin (AAT) encoded by the gene SERPINA1 is a potential risk for pulmonary disease. We investigated SERPINA1 polymorphism as a risk for infant and adult pulmonary morbidity, and adult respiratory function and its change between 43 and 53 yr. We used data on a British national representative sample (n = 5,362) studied since birth in 1946 to age 53 yr (when n = 3,035), when DNA was first obtained. SERPINA1 Z and, to a lesser extent, S carriers had an increased risk of infant lower respiratory infection compared with those who were neither S nor Z carriers (Z carriers: odds ratio = 2.32, 95% confidence interval = 1.37-3.92; S but not Z carriers odds ratio = 1.58, 95% confidence interval = 1.10-2.28) after adjustment for environmental, socioeconomic, and developmental factors, and breast-feeding. There was no difference in the adult outcomes at 53 yr according to genotype, nor was there any association of genotype with change in forced expiratory volume at 1 s between 43 and 53 yr. Lower alpha1-antitrypsin, as indicated by carrier status for the Z and S alleles, was a risk for infant lower respiratory infection, but not for adult respiratory outcomes.