20 research outputs found
Doctors’ attitudes and confidence towards providing nutrition care in practice: Comparison of New Zealand medical students, general practice registrars and general practitioners
INTRODUCTION: Improvements in individuals' nutrition behaviour can improve risk factors and outcomes associated with lifestyle-related chronic diseases
General practitioners’ views on providing nutrition care to patients with chronic disease: a focus group study
INTRODUCTION: Nutrition care refers to practices conducted by health professionals to support patients to improve their dietary intake. General practitioners (GPs) are expected to provide nutrition care to patients for prevention and management of chronic disease
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Structure-functional changes in eNAMPT at high concentrations mediate mouse and human beta- cell dysfunction in type 2 diabetes
Aims/hypothesis
Progressive decline in functional beta cell mass is central to the development of type 2 diabetes. Elevated serum levels of extracellular nicotinamide phosphoribosyltransferase (eNAMPT) are associated with beta cell failure in type 2 diabetes and eNAMPT immuno-neutralisation improves glucose tolerance in mouse models of diabetes. Despite this, the effects of eNAMPT on functional beta cell mass are poorly elucidated, with some studies having separately reported beta cell-protective effects of eNAMPT. eNAMPT exists in structurally and functionally distinct monomeric and dimeric forms. Dimerisation is essential for the NAD-biosynthetic capacity of NAMPT. Monomeric eNAMPT does not possess NAD-biosynthetic capacity and may exert distinct NAD-independent effects. This study aimed to fully characterise the structure-functional effects of eNAMPT on pancreatic beta cell functional mass and to relate these to beta cell failure in type 2 diabetes.
Methods
CD-1 mice and serum from obese humans who were without diabetes, with impaired fasting glucose (IFG) or with type 2 diabetes (from the Body Fat, Surgery and Hormone [BodyFatS&H] study) or with or at risk of developing type 2 diabetes (from the VaSera trial) were used in this study. We generated recombinant wild-type and monomeric eNAMPT to explore the effects of eNAMPT on functional beta cell mass in isolated mouse and human islets. Beta cell function was determined by static and dynamic insulin secretion and intracellular calcium microfluorimetry. NAD-biosynthetic capacity of eNAMPT was assessed by colorimetric and fluorescent assays and by native mass spectrometry. Islet cell number was determined by immunohistochemical staining for insulin, glucagon and somatostatin, with islet apoptosis determined by caspase 3/7 activity. Markers of inflammation and beta cell identity were determined by quantitative reverse transcription PCR. Total, monomeric and dimeric eNAMPT and nicotinamide mononucleotide (NMN) were evaluated by ELISA, western blot and fluorometric assay using serum from non-diabetic, glucose intolerant and type 2 diabetic individuals.
Results
eNAMPT exerts bimodal and concentration- and structure-functional-dependent effects on beta cell functional mass. At low physiological concentrations (~1 ng/ml), as seen in serum from humans without diabetes, eNAMPT enhances beta cell function through NAD-dependent mechanisms, consistent with eNAMPT being present as a dimer. However, as eNAMPT concentrations rise to ~5 ng/ml, as in type 2 diabetes, eNAMPT begins to adopt a monomeric form and mediates beta cell dysfunction, reduced beta cell identity and number, increased alpha cell number and increased apoptosis, through NAD-independent proinflammatory mechanisms.
Conclusions/interpretation
We have characterised a novel mechanism of beta cell dysfunction in type 2 diabetes. At low physiological levels, eNAMPT exists in dimer form and maintains beta cell function and identity through NAD-dependent mechanisms. However, as eNAMPT levels rise, as in type 2 diabetes, structure-functional changes occur resulting in marked elevation of monomeric eNAMPT, which induces a diabetic phenotype in pancreatic islets. Strategies to selectively target monomeric eNAMPT could represent promising therapeutic strategies for the treatment of type 2 diabetes
Relationships of low serum vitamin D3 with anthropometry and markers of the metabolic syndrome and diabetes in overweight and obesity
Low serum 25 hydroxyvitamin D3 (vitamin D3) is known to perturb cellular function in many tissues, including the endocrine pancreas, which are involved in obesity and type II diabetes mellitus (TIIDM). Vitamin D3 insufficiency has been linked to obesity, whether obesity is assessed by body mass index (BMI) or waist circumference (waist). Central obesity, using waist as the surrogate, is associated with the metabolic syndrome (MetSyn), insulin resistance, TIIDM and atherosclerotic cardiovascular disease (CVD). We tested how vitamin D3 was related to measures of fat mass, MetSyn markers, haemoglobin A1c (HbA1c) and MetSyn in a cross-sectional sample of 250 overweight and obese adults of different ethnicities. There were modest inverse associations of vitamin D3 with body weight (weight) (r = -0.21, p = 0.0009), BMI (r = -0.18, p = 0.005), waist (r = -0.14, p = 0.03), [but not body fat % (r = -0.08, p = 0.24)], and HbA1c (r = -0.16, p = 0.01). Multivariable regression carried out separately for BMI and waist showed a decrease of 0.74 nmol/L (p = 0.002) in vitamin D3 per 1 kg/m2 increase in BMI and a decrease of 0.29 nmol/L (p = 0.01) per 1 cm increase in waist, with each explaining approximately 3% of the variation in vitamin D3 over and above gender, age, ethnicity and season
Parental involvement and association with adolescents’ fruit and vegetable intake at follow-up: Process evaluation results from the multi-component school-based Boost intervention
Is the use of cholesterol-lowering drugs for the prevention of cardiovascular complications in type 2 diabetics evidence-based? A systematic review.
International audienceCholesterol-lowering drugs are often prescribed to patients with type 2 diabetes mellitus despite uncertainty about the benefits of this treatment in the prevention of cardiovascular complications. We here systematically review (PRISMA guidelines) the results of high-quality double blind trials testing whether cholesterol-lowering drugs (statins and fibrates) reduce mortality and cardiovascular complications specifically in type 2 diabetics. Trials with premature termination without pertinent medical justification or using nonrandomized subgroups of diabetics were excluded from the review. Only four trials met our predefined inclusion criteria. Among the 3 statin trials, CARDS was discontinued 2 years before the anticipated end and in the absence of significant effect on both overall and cardiovascular mortality, suggesting that the trial should not have been prematurely stopped. The two other statin trials showed no significant effect on the primary endpoint (relative risk 0.92, 95% CI 0.77 to 1.10 in 4D and 0.90, 95% CI 0.73 to 1.12 in ASPEN) and on both cardiovascular and overall mortality. Finally, the fibrate trial (FIELD) showed no significant benefit on the primary endpoint (relative risk 0.89, 95% CI 0.75 to 1.05) and mortality (relative risk 1.11, 95% CI 0.95 to 1.29). Because of a huge medical heterogeneity between patients in the selected trials, it was consensually decided to stop the analysis at this stage. This review does not support the use of cholesterol-lowering drugs (such as statin and fibrate) to reduce mortality and cardiovascular complications in type 2 diabetics. Official guidelines should be re-examined and reformulated by experts independent from the pharmaceutical industry
Low energy diet-induced and bariatric surgery-induced weight loss decreases branched-chain and aromatic amino acids in plasma and tissue (P21-078-19)
Objectives: Plasma levels of branched-chain amino acids (BCAA) and aromatic amino acids (AAA) phenylalanine (phe) and tyrosine (tyr) have been associated with obesity, insulin resistance and risk of type 2 diabetes. This study aimed to investigate the response of circulating plasma and tissue levels of BCAA and AAA to weight loss, and to correlate the level of these metabolites in plasma and tissue in obese women.Methods: 28 obese (mean BMI 46.2 kg/m2) women underwent low energy diet (LED)-induced weight loss (−9.2 ± 4.2 kg) followed by bariatric surgery-induced weight loss (−23.6 ± 2.5 kg). Plasma at baseline (t0), post-LED/pre-surgery (t1) and 6-month post-surgery (t2) as well as biopsies of subcutaneous abdomen adipose tissue (SAfat), superficial thigh adipose tissue (Tfat) and vastus lateralis thigh muscle (Tmuscle) at both t1 and t2 were collected, and profiled using mass spectrometry-based metabolomics approach. Paired t-tests were applied to assess between-timepoint differences, and Pearson correlation used to calculate correlation coefficient of metabolite levels between plasma and tissue.Results: Plasma BCAA and AAA were all significantly reduced post-LED at t1 (fold-change of 0.76–0.85 for val, leu, ile, tyr and phe, P \u3c 0.05) and 6-month post-surgery at t2 (fold-change of 0.74–0.85 for val, leu, ile, tyr and phe, P \u3c 0.05) as compared to baseline t0; but not significant between t1 and t2, although trends of decrease were observed. Among the 3 tissue biopsies, only SAfat showed significantly decreased levels of tyr, leu and ile at t2 compared to t1 (fold-change for tyr 0.63, leu 0.66, ile 0.68, P \u3c 0.05). In addition, plasma levels of val and ile were correlated with Tfat levels at both t1 and t2 (r2 = 0.47–0.57), and that of val, ile and leu were correlated with Tmuscle at t1 only (r2 = 0.64–0.67).Conclusions: Circulating levels of BCAA and AAA were decreased by weight loss interventions. The decrease following an LED program was sustained after bariatric surgery without further significant decrease. Bariatric surgery also decreased BCAA levels in SAfat; moreover, our data suggested that plasma BCAA levels correlated well with peripheral tissue Tfat and Tmuscle
16QAM Blind Equalization via Maximum Entropy Density Approximation Technique and Nonlinear Lagrange Multipliers
Recently a new blind equalization method was proposed for the 16QAM constellation input inspired by the maximum entropy density approximation technique with improved equalization performance compared to the maximum entropy approach, Godard’s algorithm, and others. In addition, an approximated expression for the minimum mean square error (MSE) was obtained. The idea was to find those Lagrange multipliers that bring the approximated MSE to minimum. Since the derivation of the obtained MSE with respect to the Lagrange multipliers leads to a nonlinear equation for the Lagrange multipliers, the part in the MSE expression that caused the nonlinearity in the equation for the Lagrange multipliers was ignored. Thus, the obtained Lagrange multipliers were not those Lagrange multipliers that bring the approximated MSE to minimum. In this paper, we derive a new set of Lagrange multipliers based on the nonlinear expression for the Lagrange multipliers obtained from minimizing the approximated MSE with respect to the Lagrange multipliers. Simulation results indicate that for the high signal to noise ratio (SNR) case, a faster convergence rate is obtained for a channel causing a high initial intersymbol interference (ISI) while the same equalization performance is obtained for an easy channel (initial ISI low)