Lipid metabolism in young men after acute resistance exercise at two different intensities.

The aim of this study was to examine the effects of different resistance training loads on blood lipids. Six healthy, untrained male volunteers performed three protocols: control (no exercise), high intensity (HI) and low intensity (LI) exercise seven days apart. Each protocol comprised eight exercises. The HI protocol used a 10-repetition maximum (RM) load and 10 repetitions. In the LI protocol, the load was halved and repetitions doubled. The volume of work performed in the two exercise protocols was identical. Blood samples were collected before, immediately after, and 15 min after each protocol and analysed for total, high density (HDL-C), low density cholesterol and triglyceride. The only significant effect of exercise was to acutely increase HDL-C in the immediate post exercise sample compared with the control. There was no significant effect on any lipid fraction resulting from the LI protocol compared with the control. The results of this study suggest that intensity alone has an effect in determining the HDL-C response to acute resistance exercise.

Risk factors for coronary heart disease in two similar Indian population groups, one residing in India, and the other in Sydney, Australia.

OBJECTIVE: To identify the prevalence of coronary risk factors among South Asian Indians in Australia and India. DESIGN: Cross-sectional intercountry comparison. SUBJECTS: Healthy volunteers aged 23-75 y recruited from the Indian community in Sydney Australia (n=125), and their nominated relatives in India, (n=125). RESULTS: The two groups were of similar background with over 90% of the group in India being siblings, parents or relatives of the group in Australia. There was no difference in the populations between India and Australia with regard to mean age (40+/-11.5 vs 39+/-10.3 y), body mass index (BMI) (25+/-3.3 vs 25+/-3.5 kg/m(2)), lipoprotein (a) (178 vs 202 mg/l), total cholesterol (5.3+/-1.3 vs 5.3+/-1.2 mmol/l) or triglyceride (1.7+/-0.8 vs 1.7+/-0.8 mmol/l). The group in India had higher insulin (median values) (139 vs 83 pmol/l, P=0.0001), waist-to-hip ratio (WHR) (0.88+/-0.08 vs 0.85+/-0.09, P=0.01), exercise time (23.7+/-32.7 vs 17.2+/-23.2 h/week, P=0.07), lower waist (83+/-10.0 vs 85+/-11.1 cm, P=0.05) and high-density lipoprotein (0.9+/-0.3 vs 1.1+/-0.6 mmol/l, P=0.02). Women in India had lower BMI (22.7+/-2.9 vs 25.3+/-4.2 kg/m(2), P<0.001), higher insulin (182 vs 90 pmol/l, P<0.001), WHR (0.86+/-0.08 vs 0.77+/-0.06, P<0.001)) and prevalence of abdominal obesity (% WHR >0.8, 73 vs 23%, P<0.001; odds of waist >90 cm=2.3, P<0.05). Men in India had the same BMI, lower waist (85.5+/-8.8 vs 92.9+/-7.2 cm, P<0.001) and WHR (0.89+/-0.09 vs 0.93+/-0.05, P<0.01) but higher insulin (137 vs 76 pmol/l). CONCLUSION: The group in Australia (especially women) have a more favourable disease risk profile than those in India. The fact that the groups are of such similar background and partly related, make it unlikely that changes due to migration have a strong genetic bias. In contrast to other studies, the absence here of excessive weight gain on migration may be a key factor in disease risk prevention.

Food, activity and family--environmental vs biochemical predictors of weight gain in children.

OBJECTIVE: To identify whether measures of energy intake and expenditure predict excessive weight gain over time in children and to describe how these measures relate to similar measures in parents. DESIGN: Prospective, descriptive study over 12 months with no intervention. SETTING: University teaching hospital. SUBJECTS: Children aged between 6.0 and 9.0 y. Recruitment was through advertisement. A total of 59 children (30 F), 41 mothers and 29 fathers. In all, 41 (69%) of the children were reviewed at 12 months (20 F). RESULTS: No significant correlations were identified between body mass index (BMI) z-score change in children over 12 months for any dietary variable or for any measures of energy expenditure, including hours of television viewing or percent time spent in low-, moderate- or high-intensity activity. The BMI z-score change over 12 months was significantly correlated with LDL cholesterol and Apo B/ApoA-1 ratio, independent of percent body fat (r=0.45, P=0.01; r=0.37, P=0.03). A significant positive correlation was found for mothers and girls for percent time in moderate to high activity (r=0.44, P=0.03) and between fathers and children for percent time spent in low activity (r=0.43, P=0.005). CONCLUSIONS: The study has been unable to identify environmental predictors that indicate propensity to faster weight gain over time in this cohort of children, but has extended the evidence on lifestyle-influenced biochemical predictors that do. An overall lack of vigorous activity in this age group, and correlations between parental and child activity and inactivity have been identified.

Comparison of a footpad analyser with a tetrapolar model for the determination of percent body fat in young men.

Since excess weight in adolescence predisposes to overweight and obesity in adulthood, a simple measure of excess adiposity in adolescents is important. Fast, inexpensive, bioelectric impedance analysers (BIA) which rely on two foot pad electrodes are now available to measure % total body fat (TBF), but are less well investigated than conventional tetrapolar models which require the subject to lie prone with four electrodes attached to hands and feet. The aim of this study was to compare the estimation of % TBF by a foot pad analyser and a tetrapolar model. Male students, n = 35, 17-19 years had height, weight, waist and hip circumferences measured and completed a questionnaire regarding age, ethnicity and time of last eating and drinking. Percent TBF was measured by a Tanita stand-on analyser (Tanita 105, Tanita Corporation, Japan) and a SEAC tetrapolar model (SEAC, SFB3, QUT, Australia). Mean age (+/- SD) of subjects = 18.2 +/- 0.6 years, BMI = 24.4 +/- 3.5 kg/m2, WHR = 0.81 +/- 0.04, % TBF, Tanita = 18.2 +/- 6.2 and SEAC = 20.4+/-4.8. Both measures of fat were correlated (r = 0.84, p<0.0001). A plot of the average versus the difference of the two analysers found the majority of differences were above zero, especially for measures of fat below 22%, indicating a negative bias for the Tanita. The limits of agreement are between -5.4 and 9% TBF. Information provided by this study will guide gymnasium operators and health professionals to comment on a relative degree of adiposity with greater confidence of data reliability.

Low-density lipoprotein subclasses in children under 10 years of age.

OBJECTIVE: To examine the prevalence of small dense low density lipoprotein (LDL) in a cohort of children under 10 years of age and to investigate the relationship to other biochemical variables and to measures of fatness. A preponderance of small dense LDL (pattern B), is associated with obesity, abdominal fat accumulation, insulin resistance and risk of heart disease in adults. METHODOLOGY: LDL peak particle diameter (PPD) was determined by gel electrophoresis in 53 children under 10 years of age and in 65 of their parents: apoproteins A1 and B were determined by turbidimetry. Anthropometric variables, basic lipid profiles, insulin and leptin had been determined previously. Differences between patterns A (large light particles > 25.5 nm diameter) and B were examined by t-test, Chi-square, or Mann-Whitney test. Relationships between the variables were reported as Pearson correlation coefficients. RESULTS: Pattern B (PPD of < or = 25.5 nm) prevalence was 7.5% in children and 11% in parents (17% in men and 5% in women). Most of the children (86%) who had PPD < or = 26.0 nm also had parents with PPD in this range. A strong association was found between children's and mother's PPD (r=0.60, P < 0.001), but this was somewhat less with fathers (r=0.40, P=0.02). Children in the lowest tertile of PPD had a tendency towards a higher body mass index, waist, fat mass and insulin. CONCLUSIONS: The prevalence of small dense LDL is lower in children under 10 years of age than in their parents; fathers had a higher prevalence of pattern B than mothers and there is some evidence of a familial effect in the inheritance of pattern B.

Regular non-vigorous physical activity and cholesterol levels in the elderly.

BACKGROUND: High-density lipoprotein cholesterol (HDL-C) is a powerful independent risk factor for coronary heart disease (CHD) among the elderly. Regular vigorous physical activity has been found to raise the concentration of HDL-C and thus reduce the risk of CHD. There is little data on the effect of non-vigorous activity on HDL-C in the elderly. OBJECTIVE: The aim of this study was to compare CHD risk factors, especially HDL-C, in a group of elderly persons who engage in regular non-vigorous physical activity with a group of frail elderly examined in a previous study. METHODS: Each subject (51 women and 19 men) had anthropometric measures taken and completed a questionnaire on lifestyle and medical history. Total cholesterol (TC), HDL-C and lipoprotein (a) were analysed. Results were compared with those of a frail group examined previously using similar methodology. RESULTS: HDL-C, adjusted for age, body mass index (BMI) and waist-to-hip ratio (WHR), was greater among women (p < 0.01) and men (p < 0.05) who were engaged in a regular physical activity at least once a week. TC was higher among active women (p < 0.001), but there was also a trend towards a lower TC/HDL ratio. Therefore, although TC is higher in active women, this could be due to a higher proportion of the cholesterol fraction consisting of HDL-C. WHR was negatively associated with HDL-C in frail men (p < 0. 05), active men (p < 0.01) and active women (p < 0.05). BMI was negatively associated with HDL-C in frail women (p < 0.05). CONCLUSIONS: This sample of elderly people who participate in regular weekly non-vigorous physical activity have a higher HDL-C than frail individuals who do little or no exercise. Since HDL-C is consistently reported to be inversely associated with CHD in the elderly, an elevation in HDL-C concentration may provide some protection to elderly persons who participate in regular nonvigorous physical activity compared to frail elderly individuals who are largely sedentary. Caution should be exercised in the interpretation of a TC only reading in active elderly women without an accompanying measure of HDL.

Coronary heart disease risk factors in male adolescents, with particular reference to smoking and blood lipids.

PURPOSE: To examine coronary heart disease (CHD) risk factors, particularly blood lipids and smoking, in adolescent boys in the Sydney Metropolitan area, and to investigate possible differences between boys from English-speaking (ESB) and non-English-speaking backgrounds (NESBs). METHODS: Male volunteers aged 15-18 years were recruited from the senior years of four secondary schools in different geographical areas of Sydney. Body mass index (BMI), waist-hip ratio (WHR), blood lipids, and percent body fat were measured. Behavioral variables were estimated by questionnaire. RESULTS: A total of 110 boys were recruited; 74% were from an ESB. Mean WHR (0.836 +/- 0.045), waist circumference (80.6 +/- 9.4 cm), and percent body fat (21.0 +/- 6.3) were similar across age groups. Atherogenicity of the lipid profile, as measured by the ratio of total cholesterol to high-density lipoprotein cholesterol (TC:HDL-C), was lower in boys aged 15 years than in any other age group (p < .05). TC:HDL-C was strongly associated with BMI (r = .57; p < .0001) and WHR (r = .35; p < .01). Smokers had higher BMI, were less active and had lower HDL-C (p < .001) and higher TC:HDL-C (p < .0001) than nonsmokers. Smoking, even of short duration, and quite moderate consumption of cigarettes (6/day) were associated with a deterioration of the lipid profile. Boys from NESBs had a higher degree of risk in all of the factors examined. CONCLUSIONS: Regular smoking of short duration has an appreciable impact on lipid and lipoprotein concentrations in this sample of Australian adolescent boys. Boys from an NESB appear to be at greater risk of developing CHD in later life.

Plasma selenium concentrations in a Sikh population in Sydney, Australia.

Selenium is essential for humans because it protects the heart against cardiomyopathy. It may also reduce ischaemic heart disease owing to its antioxidant activity. It is known that Indian migrants in a number of countries have high incidences of ischaemic heart disease. In this study, fasting plasma selenium concentrations of Sikh migrants in Sydney (Australia) were measured to investigate whether selenium concentration is reduced in this community. The mean concentration of selenium in plasma (91.8 +/- 15.0 ng ml-1, n = 196) was within the normal range. A significantly higher plasma selenium concentration was demonstrated in males than in females (p < 0.01). This was mainly due to the difference in mean selenium concentrations between genders in vegetarians because no significant difference was observed in non-vegetarian males versus females. The mean concentration of selenium in teetotal males was similar to those who consumed alcohol. Despite significant variations with gender and diet, the selenium concentrations were within the normal range. The results suggest that selenium status is adequate in the Sikh community even though vegetarian diet is common and alcohol use is condones in males.

Plasma cholesterol and other cardiac risk factors in adolescent girls.

The aim was to examine the effects of smoking, physical activity, and body mass on total cholesterol and high density lipoprotein cholesterol (HDL-C) in adolescent schoolgirls in Sydney, Australia. Body mass index (BMI) and waist to hip ratio (WHR) were determined in 144 girls aged 15 to 18 years. Total cholesterol (TC) and HDL-C were estimated on fingerprick blood and behavioural variables assessed by questionnaire. Prevalence of overweight (> 90th centile for BMI) was less in Australian adolescents than reported from the USA. Smokers had lower total cholesterol than non-smokers; this was partly explained by a lower HDL-C in the smokers. Physical activity was associated with a less atherogenic TC/HDL-C ratio. Girls with BMI > 90th centile had higher mean TC/HDL-C and apoprotein B than the group as a whole but those > 90th centile for WHR did not.

Lipid composition of gram-negative bacteria, sensitive and resistant to streptomycin.

Analyses of streptomycin-sensitive and -resistant gram-negative bacteria show that, contrary to previous reports, the development of antibiotic resistance is not accompanied by changes in membrane lipid or fatty acid composition.

Effect of streptomycin on lipid composition with particular reference to cyclic depsipeptide biosynthesis in Serratia marcescens and other micro-organisms.

The addition of low concentrations of streptomycin (5-10mug/ml of medium) to Serratia marcescens caused significant alterations in the lipid composition of this organism, but neither growth nor pigmentation was affected. The acetone-soluble cyclic depsipeptides, which comprise on average 15% of the total lipid, were decreased almost to zero and the total lipid phosphorus was more than doubled in the presence of streptomycin. Most of the phospholipid increase was due to an increase in phosphatidylethanolamine. Cyclic depsipeptides were not leached from the cell in the presence of streptomycin, indicating a definite inhibition of the biosynthetic pathway. The effect of streptomycin on the reported peptidolipids of Rhodopseudomonas spheroides, Halobacterium halobium, Nocardia asteroides and Pseudomonas tabaci was investigated. In the case of the only strictly comparable cellular cyclic depsipeptide (that of N. asteroides) the biosynthesis was strongly inhibited by streptomycin, but cell weight was maintained or even slightly increased. A possible mode and site of action of low concentrations of streptomycin on bacterial lipids is discussed.