Fasting Blood Samples (fasting + blood_sample)

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Distribution within Medical Sciences

Selected Abstracts

Elevated serum urate concentration independently predicts poor outcome following stroke in patients with diabetes

Edward J. Newman
Abstract Background Type 2 diabetes is a risk factor for stroke and confers increased risk of poor outcome and further vascular events following stroke. Hyperuricaemia occurs commonly in patients with type 2 diabetes, but its significance as a predictor of outcome following stroke is uncertain. We sought to investigate the prognostic significance of elevated serum urate concentration in diabetic subjects following stroke. Methods We studied a cohort of type 2 diabetes patients presenting to our unit with computed tomography-confirmed acute stroke. Fasting blood samples were drawn within 24 h of admission for urate concentration and standard battery of biochemistry and hematological tests. Information on age, stroke type, prior hypertension, smoking status, resolution time of symptoms and National Institutes of Health Stroke Score was collated. The main outcome event was time to myocardial infarction, recurrent stroke or vascular death, as defined in the CAPRIE trial. Stepwise proportional hazards regression was used to estimate the effect of the above variables on event-free survival following stroke. Results One hundred and forty patients were studied. Median follow-up duration was 974 days (IQR 163 to 1830 days). Sixty-four patients suffered an outcome event. Urate levels of greater than 0.42 mmol/L (p < 0.001) and an increasing NIHSS score (p < 0.001) independently predicted increased likelihood of suffering an event. Conclusion Elevated urate concentration is significantly and independently associated with increased risk of future vascular events in diabetic stroke patients. Further studies to elucidate the mechanism of this observation are required. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Androgen receptor gene polymorphism and the metabolic syndrome in 60,80 years old Norwegian men

Paal André Skjærpe
Summary The metabolic syndrome (MS) includes a clustering of metabolic derangements. Low testosterone levels have been shown to be associated with both components of MS and MS per se. As most androgen-related effects are mediated thorough the androgen receptor (AR), we wanted to investigate to which degree the AR CAG and GGN repeat polymorphisms might be related to MS. Sixty-eight men, 60,80 years old, with subnormal total testosterone levels (,11.0 nmol/L) and 104 men with normal levels (>11.0 nmol/L), participating in a nested case,control study were investigated in this study. Body weight, height, waist circumferences and blood pressure were measured. Fasting blood samples were drawn and an oral glucose tolerance test (OGTT) was performed. The CAG and GGN polymorphisms in the AR gene were determined by direct sequencing of leucocyte DNA. Men with MS had lower CAG repeat number than healthy men (p = 0.007). There were, however, no difference in CAG or GGN repeats length between the groups with subnormal or normal testosterone concentrations. In cross-sectional analyses, men with CAG repeat lengths , 21 had significantly higher fasting glucose, C-peptide and glycosylated haemoglobin (HbA1c) levels (all p < 0.05). In multiple regression analyses, CAG repeat length was an inverse and independent predictor of glucose after an OGTT and of HbA1c levels. We also found that men with more than one component of MS had shorter CAG repeat number (p for trend 0.013) than those with only one component. In conclusion, there were no associations with GGN repeat length, while short CAG repeat length seems to be associated with increased risk of MS. [source]

Diurnal triglyceridaemia and insulin resistance in mildly obese subjects with normal fasting plasma lipids

C. J. M. Halkes
Abstract. Objective., A novel method has been developed to study diurnal triglyceride (TG) profiles using repeated capillary self-measurements in an ,out-of-hospital' situation. We assessed the diurnal capillary TG (TGc) profile in males with mild obesity and evaluated the use of plasma and capillary TG as markers of insulin resistance. Design., Cross-sectional study. Setting and Subjects., Fifty-four lean (body mass index, BMI < 25 kg m,2) and 27 mildly obese (25 < BMI < 30 kg m,2), normolipidaemic males measured capillary TG concentrations on six fixed time-points over a 3-day period in an ,out-of-hospital' situation. Main outcome measures., The total area under the TGc curve (TGc-AUC) and incremental area under the TGc curve (TGc-IAUC) were used as estimation of diurnal triglyceridaemia. Fasting blood samples were obtained once. Food intake was recorded by all participants. Results., Obese and lean subjects had comparable fasting capillary TG concentrations (1.37 ± 0.40 mmol L,1 and 1.32 ± 0.53 mmol L,1, respectively). However, during the day, obese subjects showed a greater TG increase, resulting in significantly higher TGc-AUC (27.1 ± 8.4 and 23.0 ± 6.3 mmol h,1 l,1, respectively; P < 0.05) and TGc-IAUC (7.9 ± 5.8 and 4.6 ± 6.6 mmolh,1 L,1, respectively; P < 0.05). The total group of 81 males was divided into quartiles based on fasting plasma TG, fasting capillary TG, TGc-AUC and TGc-IAUC. Amongst these variables, TGc-AUC was the only significant discriminator of subjects with high homeostasis model assessment (HOMA) (insulin resistance) compared with low HOMA (insulin sensitive). Overall, BMI was the strongest determinant of HOMA. Conclusions., Diurnal TG profiles can be used to investigate postprandial lipaemia in both lean and mildly obese subjects and may help to detect subjects with an underlying disposition for hypertriglyceridaemia related to insulin resistance, i.e. the metabolic syndrome. [source]

Plasma folate status and dietary folate intake among Chinese women of childbearing age

Yaling Zhao
Abstract Maternal folic acid deficiency is an underlying risk for neural tube defects (NTDs). China has one of the highest prevalences of NTDs, and the prevalence rates of NTDs vary by region. We characterized plasma folate level and dietary folate intake among Chinese women of childbearing age by region (North and South, East and West, urban and rural) to provide evidence for establishing policy to prevent NTDs. A total of 1003 women of childbearing age from five provinces in China were interviewed. Fasting blood samples were collected. Plasma folate concentrations were determined by a microbiological assay. Dietary intake data were collected using a 24-h recall. Both the plasma folate concentrations and dietary folate intake of women in the South (25.9 nmol L,1 and 211.0 µg day,1) were higher than those of women in the North (13.3 nmol L,1 and 189.2 µg day,1). In the North, plasma folate concentrations and dietary folate intake of women in rural areas were lower than those of women in urban areas, whereas, in the South, an opposite pattern was observed. No difference was found between women in the East and West, in either the North or South regions. Plasma folate and dietary folate intake among Chinese women of childbearing age were suboptimal and varied by region. Different folic acid supplementation approaches and dosage should be undertaken to improve folate status of women in different areas. Particular attention should be paid to women in the North, especially in northern rural areas. [source]

ORIGINAL RESEARCH,ENDOCRINOLOGY: Evaluation of the Effects of Cigarette Smoking on Testosterone Levels in Adult Men

Graziele Halmenschlager MS
ABSTRACT Introduction., Cigarette smoking is highly prevalent among men. Many studies have evaluated the effect of cigarette smoking on levels of male reproductive hormones; however, the findings still remain controversial. Aim., To evaluate the influence of cigarette smoking on serum levels of total testosterone (TT), free testosterone (FT), bioavailable testosterone (BT), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH). Methods., A total of 255 men (90 smokers and 165 nonsmokers), aged 30 to 70 years, were investigated. Weight and height were obtained and body mass index (BMI) was calculated. Also, waist circumference and hip circumference were measured and waist-to-hip ratio was obtained. Fasting blood samples were drawn for determination of plasmatic glucose levels and serum levels of total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides, albumin, prolactin, TT, SHBG, LH, and FSH. The values of low-density lipoprotein cholesterol (LDL-c) were determined by Friedwald equation and the values of FT and BT were calculated from TT, SHBG, and albumin. Statistical significance was set at P , 0.05. Main Outcome Measures., The influence of smoking on levels of TT, FT, and BT. Results., No significant difference was observed in the mean values of TT (P = 0.580), FT (P = 0.869), BT (P = 0.933), SHBG (P = 0.279), LH (P = 0.573), and FSH (P = 0.693) in the different levels of pack-years when compared to nonsmokers. Moreover, after multivariate logistic regression, no association between increased pack-years of smoking and increased odds ratio for occurrence of low hormones and SHBG levels was observed. Conclusion., In this study, smokers and nonsmokers had similar mean values of androgens, gonadotropins and SHBG. However, it is necessary to standardize pack-years of smoking in order to elucidate the influence of cigarette smoking on sex hormone levels, as well as to minimize differences among studies and to confirm our results. Halmenschlager G, Rossetto S, Lara GM, and Rhoden EL. Evaluation of the effects of cigarette smoking on testosterone levels in adult men. J Sex Med 2009;6:1763,1772. [source]

Effects of antiepileptic drugs on lipids, homocysteine, and C-reactive protein,

Scott Mintzer MD
Objective The widely prescribed anticonvulsants phenytoin and carbamazepine are potent inducers of cytochrome P450 enzymes, which are involved in cholesterol synthesis. We sought to determine whether these drugs have an effect on cholesterol and other serological markers of vascular risk. Methods We recruited 34 epilepsy patients taking carbamazepine or phenytoin in monotherapy whose physicians had elected to change treatment to one of the noninducing anticonvulsants lamotrigine or levetiracetam. Fasting blood samples were obtained both before and 6 weeks after the switch to measure serum lipid fractions, lipoprotein(a), C-reactive protein, and homocysteine. A comparator group of 16 healthy subjects underwent the same serial studies. Results In the epilepsy patients, switch from either phenytoin or carbamazepine produced significant declines in total cholesterol (,24.8mg/dl), atherogenic (non,high-density lipoprotein) cholesterol (,19.9mg/dl), triglycerides (,47.1mg/dl) (all p < 0.0001), and C-reactive protein (,31.4%; p = 0.027). Patients who stopped taking carbamazepine also had a 31.2% decline in lipoprotein(a) level (p = 0.0004), whereas those taken off phenytoin had a decrease in homocysteine level (,1.7,mol/L; p = 0.005). All of these changes were significant when compared with those seen in healthy subjects (p < 0.05). Results were similar whether patients were switched to lamotrigine or levetiracetam. Interpretation Switching epilepsy patients from the enzyme-inducers carbamazepine or phenytoin to the noninducing drugs levetiracetam or lamotrigine produces rapid and clinically significant amelioration in several serological markers of vascular risk. These findings suggest that phenytoin and carbamazepine may substantially increase the risk for cardiovascular and cerebrovascular disease. Ann Neurol 2009;65:448,456 [source]

Prevalence of undiagnosed Type 2 diabetes and impaired fasting glucose in older B ritish men and women

M. C. Thomas
Abstract Aim To estimate the prevalence of undiagnosed diabetes and impaired fasting glucose in older British men and women, using the 1999 World Health Organization (WHO) thresholds based on fasting glucose measurements. Methods Participants in the British Regional Heart Study and the British Women's Heart and Health Study were selected from one socially representative general practice in 24 British towns. Included in this analysis were 3736 men and 3642 women aged 60,79 years (predominantly white), who provided a single fasting blood sample at a clinical examination between 1998 and 2001, and who had no previous diagnosis of diabetes. Results Two hundred and eleven men (5.7%) and 190 women (5.2%) had a fasting blood glucose level consistent with the WHO threshold for a diagnosis of diabetes (, 7.0 mmol/l), whilst a further 667 men (17.9%) and 642 women (17.6%) had impaired fasting glucose levels (6.1 , 7 mmol/l). When analyses were restricted to subjects who had fasted for at least 8 h, and whose blood sample was taken before 12.00 h, the predicted prevalence of undiagnosed diabetes (based on two separate measurements) was 6.7% in men and 6.0% in women. The predicted prevalence of impaired fasting glucose (based on two separate measurements) was approximately 20% in both sexes. Conclusions More than one-fifth of older white British men and women have either undiagnosed diabetes or impaired fasting glucose according to new WHO criteria. Strategies for the primary and secondary prevention of Type 2 diabetes among older individuals are urgently needed. [source]

Selection of the most informative individuals from families with multiple siblings for association studies

Chunyu Liu
Abstract Association analyses may follow an initial linkage analysis for mapping and identifying genes underlying complex quantitative traits and may be conducted on unrelated subsets of individuals where only one member of a family is included. We evaluate two methods to select one sibling per sibship when multiple siblings are available: (1) one sibling with the most extreme trait value; and (2) one sibling using a combination score statistic based on extreme trait values and identity-by-descent sharing information. We compare the type I error and power. Furthermore, we compare these selection strategies with a strategy that randomly selects one sibling per sibship and with an approach that includes all siblings, using both simulation study and an application to fasting blood glucose in the Framingham Heart Study. When genetic effect is homogeneous, we find that using the combination score can increase power by 30,40% compared to a random selection strategy, and loses only 8,13% of power compared to the full sibship analysis, across all additive models considered, but offers at least 50% genotyping cost saving. In the presence of genetic heterogeneity, the score offers a 50% increase in power over a random selection strategy, but there is substantial loss compared to the full sibship analysis. In application to fasting blood sample, two SNPs are found in common for the selection strategies and the full sample among the 10 highest ranked single nucleotide polymorphisms. The EV strategy tends to agree with the IBD-EV strategy and the analysis of the full sample. Genet. Epidemiol. 2009. © 2008 Wiley-Liss, Inc. [source]

Reduced gains in fat and fat-free mass, and elevated leptin levels in children and adolescents with cystic fibrosis

ML Ahmed
Aim: Bodyweight is an important prognostic indicator in children with cystic fibrosis (CF), but the relationships between body composition and clinical outcomes are less clear. We have investigated the role of leptin (a potential satiety factor) and changes in body composition, height and weight with respect to age and clinical outcome. Methods: 143 children (77 boys) with CF and a median age (range) of 5.99 (2.27,17.98) y were followed with annual measurements of height, weight, skinfolds, forced expiratory volume (FEV1), Shwachman score assessment and fasting blood sample. Our control group comprised 40 children (20 boys, 20 girls) aged 8.6,10.2 y at recruitment who were participating in a longitudinal study of growth and puberty. Results: SD scores for height, weight and BMI decreased with age; fat and fat-free mass was lower in both sexes compared to controls. Shwachman score decreased with age in both sexes and was related to fat-free mass in girls, and to both fat-free and fat mass in boys. FEV1 decreased with age only in boys and was related to fat-free mass. Leptin levels by age and by fat mass were higher in CF children compared to controls. Conclusion: Despite improvements in management, contemporary children with CF still gain less body fat and fat-free mass and are shorter than controls. The higher leptin levels we observed may be due to stimulatory effects of inflammatory cytokines and we postulate that they may contribute to the anorexia, poor weight gain and growth of these children. [source]

The population prevalence of adverse concentrations and associations with adiposity of liver tests among Australian adolescents

Michael L Booth
Aim: Paediatric overweight has a high incidence and has serious consequences for health, including non-alcoholic fatty liver disease (NAFLD). However, very little is known about NAFLD among young people, particularly from a population perspective. This paper reports the prevalence of elevated concentrations of four liver enzymes and their associations with adiposity in a representative population sample of Australian adolescents. Methods: Overnight fasting blood samples were collected from a representative population sample of 500 Grade 10 students (15-years-old) attending schools in Sydney, Australia, between February and May, 2004. Weight, height and waist girth were measured. The prevalence of adverse concentrations of the enzymes alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were described for all boys and girls and by body mass index (BMI) categories. The nature of the associations between the enzyme concentrations and indices of adiposity were characterised, and regression equations for estimating enzyme concentrations from BMI were prepared. Results: The prevalence of adverse concentrations of ALT (most likely as a result of NAFLD) and GGT were approximately 10%, while the prevalence of adverse concentrations of AST and ALP were approximately 7% and 5% respectively. The prevalence of adverse concentrations of ALT, GGT and AST increased across BMI categories, while the prevalence of adverse concentrations of ALP declined across BMI categories. Conclusions: The high prevalence of NAFLD in a population sample of healthy Australian adolescents represents a significant burden of disease. [source]

Intake of Maillard reaction products reduces iron bioavailability in male adolescents

Marta Mesías García
Abstract The effects of diets with different Maillard reaction products (MRPs) content on biological iron utilization were compared using in vitro/in vivo assays. Diets were rich (brown diet, BD) or poor (white diet) in MRP. In vitro studies included iron solubility after in vitro digestion of diets and iron transport across Caco-2 cells. In the human assay 18 healthy adolescent males (11,14 years) participated in a 2-wk randomized two-period crossover trial. Subjects collected urine and faeces on the last 3 days of each dietary period, and fasting blood samples were obtained after periods. In vitro dietary iron availability was significantly lower with the BD than the white diet (9.52 and 12.92%, respectively), as a consequence of the lower iron solubility after the in vitro digestion, but not as a result of decreased transport of the remaining soluble iron. The BD consumption increased iron fecal excretion (,1.4-fold) and significantly decreased its bioavailability (,2.7-fold), mainly due to the effects found at digestive level. Serum biochemical parameters related to iron metabolism remained unaltered. It is concluded the presence of MRP in the diet negatively affects iron bioavailability. As iron deficiency may be related to learning impairment and to reductions of cognitive and physical functions, possible long-term effects of excessive MRP intake during adolescence warrant attention. [source]

Baseline Leptin Levels Predict Change in Leptin Levels During Weight Loss in Obese Breast Cancer Survivors

Ananda Sen PhD
Abstract:, Leptin is an adipocyte-derived hormone involved in regulation of satiety, and it also appears to have a role in breast cancer risk. Leptin therefore might be a useful indicator of the potential preventive effects of weight loss in breast cancer survivors. In this study we examined whether the change in leptin levels could be predicted by weight loss in obese breast cancer survivors. The subjects in this study were participating in a randomized trial of an individualized approach towards weight loss in Detroit, MI. Breast cancer survivors (body mass index of 30,44 kg/m2) were enrolled and fasting blood samples were obtained for leptin analysis over 1 year of study. Leptin levels were available from at least two time points for 36 women, and weight change ranged from a gain of 11% to a loss of 25% of baseline weight. Using a repeated-measures regression model, both baseline leptin level and concurrent percent body fat were found to synergistically predict leptin levels. Thus, for women with the same body fat, those with higher baseline leptin levels are predicted to exhibit smaller decreases in leptin with weight loss. Similar results were obtained for body weight and body weight change, but the associations with body fat were stronger. Breast cancer survivors with initially higher leptin levels may differ with regard to regulation of change in leptin during weight loss resulting in relatively smaller changes in leptin with equivalent amounts of weight loss. [source]

Genetic and lifestyle variables associated with homocysteine concentrations and the distribution of folate derivatives in healthy premenopausal women

Carolyn M. Summers
Abstract BACKGROUND Low folate and high homocysteine (Hcy) concentrations are associated with pregnancy-related pathologies such as spina bifida. Polymorphisms in folate/Hcy metabolic enzymes may contribute to this potentially pathogenic biochemical phenotype. METHODS The study comprised 26 Caucasian and 23 African-American premenopausal women. Subjects gave fasting blood samples for biochemical phenotyping and genotyping. Total Hcy (tHcy) and both plasma and red blood cell (RBC) folate derivatives (i.e. tetrahydrofolate [THF], 5-methylTHF [5-MTHF], and 5,10-methenylTHF [5,10-MTHF]) were measured using stable isotope dilution liquid chromatography, multiple reaction monitoring, and mass spectrometry. Eleven polymorphisms from nine folate/Hcy pathway genes were genotyped. Tests of association between genetic, lifestyle, and biochemical variables were applied. RESULTS In African American women, tHcy concentrations were associated (p < 0.05) with total RBC folate, RBC 5-MTHF, B12, and polymorphisms in methionine synthase (MTR) and thymidylate synthase (TYMS). In Caucasian women, tHcy concentrations were not associated with total folate levels, but were associated (p < 0.05) with RBC THF, ratios of RBC 5-MTHF:THF, and polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) and MTR. In African Americans, folate derivative levels were associated with smoking, B12, and polymorphisms in MTR, TYMS, methionine synthase reductase (MTRR), and reduced folate carrier1 (RFC1). In Caucasians, folate derivative levels were associated with vitamin use, B12, and polymorphisms in MTHFR, TYMS, and RFC1. CONCLUSIONS Polymorphisms in the folate/Hcy pathway are associated with tHcy and folate derivative levels. In African American and Caucasian women, different factors are associated with folate/Hcy phenotypes and may contribute to race-specific differences in the risks of a range of pregnancy-related pathologies. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc. [source]