Plasma leptin and insulin levels in Aymara natives from Chile

The purpose of this study was to examine the relationship of plasma leptin levels with respect to obesity, gender, age and insulin levels in the native Aymara population. The Aymara natives live at high altitudes in isolated regions in the north of Chile, and they maintain distinctive genetic and cultural characteristics. Plasma leptin and insulin levels were correlated with body mass index (BMI), sex and age in a sample of 147 adult Aymara subjects who participated in a cross-sectional study. Multivariate analysis showed significant differences in leptin levels (dependent variable: natural log of leptin) by gender (p < 0.0001), and by BMI (p < 0.001), without significant statistical interaction between gender and BMI. The effect of age achieved statistical significance in the multivariate analysis (p = 0.02). Gender, BMI and insulin are independently associated with plasma leptin levels. On the other hand, the multivariate analysis of the plasma insulin concentration (dependent variable: natural log of insulin levels) shows that insulin is strongly associated with BMI (p < 0.0001), although non-statistically significant differences of insulin levels by sex (p = 0.07) or age (p = 0.9) were detected at alpha 0.05 level. Thus, in the special ecosystem where the Aymara population live, a strong and independent association between sex, obesity and insulin levels with plasma leptin levels has been detected.     

Pubertal development and sedentary behaviour during adolescence

Background: Assessing time spent in sedentary behaviours in relation to pubertal status, anthropometric differences, and body image will improve insight into the prevalence and determinants of such behaviours during adolescence.

Aim: The study aimed to investigate the effects of age, puberty, gender, body composition, and sleep on sedentary behaviour.

Participants and methods: Participants were 64 boys and 55 girls in Year 6 (10.0–10.9 years of age), Year 8 (12.0–12.9 years) and Year 10 (14.0–14.9 years). Body mass index and percentage body fat were calculated from anthropometric measures. Sedentary behaviour and sleep time were computed using momentary-time sampling. Body image was measured using the Children's Physical Self-Perception Profile. Pubertal status was assessed from self-report of secondary sexual characteristics.

Results: After controlling for sleep time, no differences in sedentary time were seen for puberty onset or increased pubertal development. Correlations between pubertal status, body composition, and body image were stronger in girls than in boys. Correlations between body image and sedentary behaviour were not strong enough to infer behavioural choice differences.

Conclusions: Reduced sleep time rather than changing body image and body composition during adolescence is associated with greater sedentary behaviour.     

Embryo reduction and birth weight discordance in dichorionic twins

BACKGROUND: Twin birth weight discordance is associated with a poor perinatal outcome. The aim of this study was to analyse the risk factors of growth discordance among dichorionic twin pregnancies. METHODS: A cohort of 346 dichorionic twin pregnancies delivered at one perinatal centre between January 1996 and December 1999 was analysed. Two groups were created, according to the presence or absence of intra-pair birth weight discordance (n = 75 and 271 respectively). Birth weight discordance was defined as a difference of >/=20% of the weight of the heavier twin. The two groups were compared by uni- and multivariate analysis, with regard to the woman's characteristics, risk factors for growth restriction or discordance, and outcome of pregnancy. RESULTS: Pregnancies with birth weight discordance had a poor outcome compared with pregnancies without discordance, with a 4-fold increase in neonatal mortality. The rate of iatrogenic embryo reduction was significantly higher in discordant pregnancies (14.7 versus 6.6%, P = 0.03). The risk of birth weight discordance was increased with a larger starting number of embryos before reduction [20.2% (64/317), 28.6% (6/21), 57.1% (4/7) and 100% (1/1) respectively, for an initial number of two (no reduction), three, four, and five embryos, P = 0.02]. In multivariate analysis, embryo reduction was the only significant risk factor for the occurrence of birth weight discordance [adjusted odds ratio (OR) = 2.3 (1.0-5.2)]. CONCLUSIONS: Birth weight discordance carries a poor perinatal outcome. Embryo reduction is an independent risk factor for birth weight discordance in dichorionic twins. This finding emphasises the need for better control of assisted reproductive technology in order to avoid high-order multiple pregnancies.     

Birth weight in pre-eclamptic and normotensive twin pregnancies: an analysis of discordance and growth restriction

The aim of this study was to verify whether twin pregnancies complicated by pre-eclampsia were associated with a higher rate of inter-twin weight discordance or an increased prevalence of small for gestational age (SGA) neonates than in normotensive twin pregnancies. A 17 year retrospective study was undertaken by examining 76 twin pregnancies complicated by pre-eclampsia and comparing them with 400 normotensive twin pregnancies. The case notes were reviewed in reference to birth weight differences, birth order, pregnancy outcome and inter-twin birth weight discordance. Statistical analyses were performed with t-test, contingency tables, regression curves, rank sum test and non-parametric survival plots. Power analysis was also carried out. Pre-eclamptic twin pregnancies were delivered at similar weeks of gestation to normotensive. They resulted in a smaller size for the second twin the earlier the delivery week, while in normotensive twin pregnancies no significant difference occurred at any week. Twin pregnancies complicated by pre-eclampsia showed higher rates of SGA neonates among second twins than those with normal pressure. The >25% discordance was associated with lower gestational age at delivery in each group [mean (range) 33 weeks (27-38) versus 37 (29-41), P < 0.005 pre-eclampsia and 35 weeks (25-41) versus 38 (25-42), P < 0.001 normotensive]. In pre-eclampsia the concomitant occurrence of SGA second twin and the discordance >25% was associated with shorter gestation while the presence of SGA second twin alone was not.     

A comparison of the merits of using birth weight,or appropriateness of birth weight to gestational age,in the assessment of subsequent growth in twin children

Background: Size at birth has an important relationship to subsequent growth. Many reports subgroup subjects according to birth weight or birth weight in relation to the duration of gestation, and it is not clear whether one of these methods is more relevant to subsequent growth or if in fact they are comparable.

Aim: The present study compared the outcome of twins in terms of pre-pubertal weight and height when sub-grouped according to birth weight (BW), or the appropriateness of birth weight for the duration of gestation (BW-SDS).

Subjects and methods: The birth weights of 1533 twins were graded into four subgroups according to BW or BW-SDS. The relationship of birth weight to subsequent weight and height standard deviation scores, obtained between the ages of 2 and 9 years, were compared on the basis of these two methods.

Results: There was a marked difference in identity of the twins who fell into each of the four subgroups by the two methods. Despite this, no difference was found in the subsequent weight and height of the twins.

Conclusions: Analysis of data relating BW-SDS to subsequent growth shows no significant difference to those groups using BW alone.     

Handedness in twins according to zygosity and chorion type: A preliminary report

In the course of the East Flanders Prospective Twin Survey (EFPTS), handedness was assessed as part of a genealogical study (Meulemanset al., 1995) in 1616 twins (808 twin pairs) aged 6 to 28. Our findings are that, in this large population-based study with known placentation and zygosity, the often observed higher frequency of left-handedness in twins is confirmed, that it appears to be independent of zygosity and chorion type, and that the belief that discordant handedness in monozygotic twins represents mirrorimaging is mythical.     

Serum leptin levels in gastric cancer patients and the relationship with insulin resistance

Introduction

Serum leptin levels have been examined in various cancers, with conflicting results. However, there is limited information regarding serum leptin levels and insulin resistance in gastric cancer patients. Therefore, we aimed to investigate serum leptin levels, performance status, insulin levels and insulin resistance in patients with gastric cancer. In addition, we examined the relationship between these measurements and leptin levels.

Material and methods

Thirty-nine patients with gastric cancer and 30 control subjects were enrolled in the study. Serum leptin, total protein, albumin, growth hormone, insulin and glucose levels were measured. The homeostasis model assessment (HOMA) was used to assess insulin resistance.

Results

Serum levels of insulin, glucose and growth hormone and insulin resistance were significantly lower in gastric cancer patients than controls (p < 0.05 for all). In the Pearson correlation analysis, insulin resistance was found to be significantly correlated with serum leptin levels in gastric cancer patients (r = 0.320, p = 0.047). We observed a significant negative correlation between performance status and insulin resistance in patients with cachexia (r = –0.512, p = 0.030), while no association was found in non-cachectic patients.

Conclusions

We concluded that serum leptin levels are significantly lower in gastric cancer patients. In addition, gastric cancer patients have decreases in insulin levels, insulin resistance and growth hormone levels. This study found a positive association between serum leptin levels and insulin resistance. Moreover, there is a negative association between serum leptin levels and growth hormone levels. Thus, low insulin and growth hormone levels may suppress the production of leptin in gastric cancer patients.     

孕妇血浆同型半胱氨酸水平与新生儿出生体重的关系

目的探讨孕妇血浆同型半胱氨酸（hcy）水平与新生儿出生体重的关系。方法采用病例对照研究,用高效液相色谱荧光检测法（HPLC-FD）检测60例孕28-34周早产孕妇（病例组）和30例于孕31-34周采血的正常妊娠孕妇（对照组）的血浆同型半胱氨酸水平。用直线相关等统计学方法分析孕妇血浆同型半胱氨酸水平与新生儿出生体重的关系。结果孕妇血浆同型半胱氨酸水平与新生儿出生体重呈负相关关系（早产病例组r=-0.696,P〈0.01;正常对照组r=-0.733,P〈0.01）,早产孕妇血浆同型半胱氨酸水平升高会增加分娩早产小于胎龄儿（SGA）的危险,尤其是早产孕妇血浆同型半胱氨酸水平≥11.0μmol/L时分娩SGA的可能性明显增加（χ^2=8.579,P=0.003）。结论新生儿出生体重受孕妇血浆同型半胱氨酸水平影响,早产孕妇血浆同型半胱氨酸水平升高会显著增加分娩小于胎龄儿的危险。     

Exercise limb blood flow response to acute and chronic hypoxia in Danish lowlanders and Aymara natives

Aim: The femoral artery blood flow response to submaximal, one‐legged, dynamic, knee‐extensor exercise was determined in acute and chronic hypoxia to investigate the hypotheses that with adaptation to chronic hypoxia blood haemoglobin increases, allowing preservation of blood flow as in normoxia. Methods: Sixteen Danish lowlanders participated, in groups of six to eight, in the experiments at sea level normoxia (FiO₂ ? 0.21) and acute hypoxia (FiO₂ ? 0.11), and chronic hypoxia after ～7 and 9–10 weeks at ～5260 m altitude breathing ambient air (FiO₂ ? 0.21) or a hyperoxic gas (FiO₂ ? 0.55). The response was compared with that in six Aymara natives. Results: The haemoglobin and haematocrit increased (P < 0.003) in the lowlanders at altitude vs. at sea level by ～39 and 27% respectively; i.e. to a similar (P = ns) level as in the natives. At rest, blood flow was the same (P = ns) in the lowlanders at sea level and altitude, as in the natives at altitude. During the onset of and incremental exercise, blood flow was the same (P = ns) in the lowlanders at sea level and altitude, as in the natives at altitude. Acute hypoxia increased (P < 0.05) blood flow by ～55% during exercise in the lowlanders at sea level. Acute hyperoxia decreased (P < 0.05) blood flow by ～22–29% during exercise in the lowlanders and natives at altitude. Conclusion: In chronic hypoxia, blood haemoglobin increases, allowing normalization of the elevated exercise blood flow response in acute hypoxia, and preservation of the kinetics and steady‐state exercise blood flow as in normoxia, being similar as in the natives at altitude.     

Plasma leptin and insulin in C57Bl/6J mice on a high-fat diet: relation to subsequent changes in body weight

It has been proposed that leptin and insulin through central effects are involved in the regulation of energy balance and body weight. Whether circulating leptin or insulin levels predict subsequent changes in body weight is, however, not known. We examined plasma leptin and insulin at 2, 3, 6, 9 and 12 months of age in C57Bl/6J mice given a normal diet (n = 12) or a high-fat diet (58% fat on a caloric base; n = 15). Plasma leptin levels increased by age and correlated with body weight in the entire material (r = 0.81, P < 0.001). Also plasma insulin increased by high-fat diet and correlated across all age periods with body weight (r = 0.56, P < 0.001). In mice, given normal diet, plasma leptin or insulin did not correlate to subsequent changes in body weight at any of the time points studied. However, in mice given the high-fat diet, plasma leptin at 6 (r = ?0.57, P = 0.027) and 9 months of age (r = ?0.56, P = 0.042) as well as plasma insulin at 6 (r = ? 0.51, P = 0.049) and 9 months (r = ?0.58, P = 0.037) correlated inversely to the change in body weight during the subsequent 3-month period. Hence, both leptin and insulin are negative predictors for future weight gain in high-fat fed mice. This suggests that when the regulation of body weight is challenged by a high-fat diet, leptin and insulin act to restrain or prevent future weight gain. This in turn may suggest that impairment of these (probably central) actions of leptin and insulin might underlie excessive increase in body weight under such conditions.     

Impact of acute sleep restriction on cortisol and leptin levels in young women

Sleep restriction alters hormone patterns and appetite in men, but less is known about effects on women. We assessed effects of overnight sleep restriction on cortisol and leptin levels and on appetite in young women. Participants' baseline sleep duration and eating habits were monitored for a week before the study. Salivary cortisol and leptin were sampled from fifteen healthy women (aged 18-25) during two consecutive days: first after a 10 h overnight sleep opportunity (Baseline day) and then after a night including only 3 h sleep (Post sleep-restriction day). Participants also completed appetite questionnaires on both days. Sleep restriction significantly reduced morning cortisol levels (p = 0.02), elevated morning leptin levels (p = 0.04), elevated afternoon/evening cortisol area under the curve values (p = 0.008), and slowed the decline in cortisol concentration during the day (p = 0.04). Hunger and craving scores did not differ significantly between days. A single night of restricted sleep affected cortisol rhythms and morning leptin levels in young women.     

Adiponectin and leptin levels in HIV-infected subjects with insulin resistance and body fat redistribution

In this study, we sought to determine the relationship between serum levels of leptin and adiponectin (Acrp30) in patients with HIV-associated lipodystrophy (HIV-LD). Three groups of subjects were studied; HIV-positive subjects with lipodystrophy (HIV-LD; n = 22), HIV-positive subjects without lipodystrophy (HIV; n = 17), and ethnicity- and body mass index-matched healthy control subjects (n = 20). Although total body fat from dual energy x-ray absorptiometry was similar in all three groups, the HIV-LD group had a significantly lower mean proportion of body fat in the limbs +/- SEM (37.2% +/- 2.2%) than either controls (49.8% +/- 1.5%) or HIV subjects (45.7% +/- 2.0%). The HIV-LD group also had the lowest mean insulin sensitivity +/- SEM (5.11 +/- 0.59 mg of glucose/[kg of lean body mass. min] vs. 10.2 +/- 0.72 mg of glucose/[kg of lean body mass. min] in controls and 8.64 +/- 0.69 mg of glucose/[kg of lean body mass. min] in the HIV group). Leptin levels were similar in all three groups and were significantly correlated to total body fat (r = 0.86; p <.001), but these levels did not correlate with either insulin sensitivity or limb fat. Mean Acrp30 levels +/- SEM were lowest in the HIV-LD group (5.43 +/- 0.44 microg/mL vs. 11.2 +/- 1.4 microg/mL in the HIV group and 14.9 +/- 1.8 microg/mL in control subjects). Further, Acrp30 levels were positively correlated with insulin sensitivity (r = 0.610; p <.001) and limb fat (r = 0.483; p <.001). However, the correlation between limb fat and insulin sensitivity disappeared when Acrp30 level and other potential mediators were removed from the association, suggesting that a deficiency in Acrp30 in subjects with HIV-LD may be part of the mechanism for the reduced insulin sensitivity.     

Plasma leptin levels in obese and non-obese postmenopausal women before and after hormone replacement therapy

Objective: the aim of this study was to investigate the effect of hormone replacement therapy (HRT) on plasma leptin levels in postmenopausal women, and the relationship between the plasma leptin levels and obesity. Methods: premenopausal women with normal cycles (n=30; mean ages, 35.4±8.3 years) and postmenopausal women (n=45; mean ages, 49.5±4.7 years) were randomly selected. Women were classified as obese (BMI>27 kg/m²) and as non-obese (BMI<27 kg/m²). Blood samples were obtained from the premenopausal women at the beginning of cycle, and from the postmenopausal women before and 6 months after HRT. Plasma leptin levels were measured by radioimmunassay. Results: plasma leptin levels were significantly higher in premenopausal women than in postmenopausal women (18.60±5.0; 3.67±2.44 ng/ml, respectively, P<0.001). Obese premenopausal women (n=15) had significantly higher plasma leptin levels (24. 60±7.81 ng/ml) in comparison with the levels of the non-obese premenopausal women (n=15; 12.50±4. 63 ng/ml) (P<0.001). Although there was no significant difference in the plasma leptin levels between obese (n=25) and non-obese (n=20) postmenopausal women before HRT, plasma leptin levels were significantly elevated in both obese and non-obese postmenopausal women after HRT (P<0.001), and the obese women had significantly higher plasma leptin levels than the non-obese (29.05±10.53; 14.78±6.76 ng/ml, respectively, P<0.001). Conclusion: HRT is effective in the elevation of the plasma leptin levels in postmenopausal women, and in obese women the increase of the plasma leptin levels are more marked than the non-obese women after HRT.     

Human placental growth hormone is increased in maternal serum at 20 weeks of gestation in pregnancies with large-for-gestational-age babies

To investigate the relationship between maternal serum concentrations of placental growth hormone (GH-V), insulin-like growth factor (IGF)-1 and 2, IGF binding proteins (IGFBP)-1 and 3 and birth weight in appropriate-for-gestational-age (AGA), large-for-gestational-age (LGA) and small-for-gestational-age (SGA) cases in a nested case-control study. Maternal serum samples were selected from the Screening for Pregnancy Endpoints (SCOPE) biobank in Auckland, New Zealand. Serum hormone concentrations were determined by ELISA. We found that maternal serum GH-V concentrations at 20 weeks of gestation in LGA pregnancies were significantly higher than in AGA and SGA pregnancies. Maternal GH-V concentrations were positively correlated to birth weights and customized birth weight centiles, while IGFBP-1 concentrations were inversely related to birth weights and customized birth weight centiles. Our findings suggest that maternal serum GH-V and IGFBP-1 concentrations at 20 weeks' gestation are associated with fetal growth.     

新生儿血清瘦素水平变化与胰岛素和生长激素关系的研究

目的　探讨新生儿血清瘦素来源及其与胰岛素和生长激素的关系。方法　采用放射免疫法检测 80例新生儿静脉血和脐血瘦素水平 ,根据不同胎龄新生儿出生体重值分为大于胎龄儿 (LGA)组 2 8例 ,适于胎龄儿 (AGA)组 36例 ,小于胎龄儿 (SGA)组 16例 ;采用Rohrer′s指数 =出生体重 (g)× 10 0 /身长 (cm) 3 估测新生儿营养状态。结果　早产儿血清瘦素水平明显低于足月儿 (0 6 6± 1 0 3ng/mlvs 3 5 9± 2 16ng/ml,P <0 0 1) ;AGA儿血清瘦素水平 (3 0 6± 0 96ng/m1)明显低于LGA儿(4 0 3± 2 2 2ng/m1) ,而高于SGA儿 (1 13± 1 98ng/m1) ;足月新生儿血清瘦素水平与Rohrer′s指数、新生儿体重、胎龄 ,血清胰岛素、生长激素水平呈显著正相关。结论　新生儿体内瘦素主要来源于自身脂肪组织 ,它反映新生儿的生长营养状态 ,推测瘦素可能通过胰岛素、生长激素共同调节新生儿的生长发育 ,在胎儿和新生儿生长发育中起重要作用。     

Resveratrol increases serum adiponectin level and decreases leptin and insulin level in an experimental model of hypercholesterolemia

Serum adiponectin concentration is inversely associated with leptin and insulin concentration. There is little paucity of information in the literature on the adipokine levels and regulation by resveratrol in cholesterol diet-fed animals. Thirty rabbits were randomly divided into six groups, each of five animals: Group 1 = control (C), Group 2 = cholesterol diet (CD) only, Group 3 = resveratrol 200?mg/kg (R200), Group 4 = resveratrol 400?mg/kg (R400), Group 5 = CD + R200, Group 6 = CD + R400. The preparations were administered for 8th weeks of the treatment protocol. weight and blood glucose level were measured on week zero and the 8th week of the treatment. At the end of the study period, the rabbits were placed under light anaesthesia. Blood samples were evaluated for serum concentrations of metabolites assays (adiponectin, leptin and insulin). Serum adiponectin significantly (P < 0.05) increased in resveratrol + CD groups, compared to CD group only. Leptin and insulin significantly (P <0.05) decreased in CD groups co-administered with resveratrol, compared with CD group only. In conclusion, the increase in adiponectin level and decrease in leptin and insulin level following resveratrol administration elucidated the therapeutic potential of resveratrol, despite cholesterol diet consumption.     

Elevated MSAFP levels and congenital heart defects: Lack of an association

This study was undertaken to evaluate the relationship between elevated maternal serum alpha fetoprotein (MSAFP) lavels and congenital heart defects. Thirty-two infants with isolated major congenital heart defects and whose mothers had had MSAFP screening were identified. In only one case was the MSAFP greater than 2.3 multiples of the median. A review of our experience with women with elevated MSAFP levels did not document a higher rate of congenital heart malformations than would be expected based on estimated frequencies in the general population. © 1994 Wiley-Liss, Inc.     

Polymorphisms in the Angiotensin Converting Enzyme Gene and Growth in the First Year of Life

Abnormal patterns of fetal and infant growth have been associated with an increased risk of cardiovascular disease in adulthood. Catch‐up growth during the first year of life has been associated with a higher prevalence of type 2 diabetes mellitus, whereas a lack of catch‐up growth tracks with a risk of hypertension. The role of genetic factors influencing both growth and blood pressure have not been explored. We genotyped cord blood samples from 530 singleton, Caucasian, uncomplicated pregnancies, drawn from a larger cohort of 1650 pregnancies, and related polymorphism in the angiotensin converting enzyme (ACE) gene (alleles insertion (I) or deletion (D)) with measures of size at birth and at age of 1 year. ACE genotype did not significantly influence size at birth, although there was a greater proportion of individuals with the D/D genotype born with a birth weight less than the 10^th centile (P = 0.004). The ACE I/I genotype was significantly associated with higher weight (p = 0.001), body mass index (p = 0.001) and mid arm circumference (p = 0.001) at 1 year of age compared to the ACE D/D and I/D genotypes. Individuals with the I/I genotype displayed catch‐up (gain from birth size of ≥0.6 Standard Deviation Score) in weight (p = 0.04), body mass index (p = 0.03) and mid arm circumference (p = 0.03) compared to the D/D group, the majority of which showed no change or catch‐down. The I/D genotype was distributed equally across the catch up/catch down/no change categories. The effect was more marked in males, but ACE genotype and sex of the infant contributed independently to mid arm circumference measurements and there was no interaction between the two. There was no effect of maternal or paternal ACE genotype on birth size. In a multiple linear regression model ACE genotype, socioeconomic status and sex of the infant explained 10.9% of the variance in body mass index SDS at 1 year of age. We conclude that the ACE I/I genotype is associated with a higher weight and body mass index SDS at 1 year of age, along with catch‐up in terms of these measures from birth to 1 year. The D/D genotype is associated with a greater proportion of babies, born at term, that at small for gestational age. These results suggest that due consideration should be given to the underlying genotype of an individual when evaluating the association of early human growth with the development of risk factors for cardiovascular disease. The observation of independent effects of genotype, sex of the individual and socioeconomic status on postnatal growth suggests the need to develop methodologies for the integration of genetic and environmental factors in causality modelling.