173 research outputs found

    Evidence for metabolic activity of airborne bacteria

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    Aerosols of the bacterium Serratia marcescens, and of uniformly labelled C-14 glucose, were created simultaneously and mixed in tubing leading to an aerosol chamber. During a subsequent period of about 5 hrs, C-14O2 was produced unequivocally within the chamber, and insoluble, labelled material within the suspended particles first increased, then decreased

    A global assessment of surveillance methods for dominant malaria vectors

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    The epidemiology of human malaria differs considerably between and within geographic regions due, in part, to variability in mosquito species behaviours. Recently, the WHO emphasised stratifying interventions using local surveillance data to reduce malaria. The usefulness of vector surveillance is entirely dependent on the biases inherent in the sampling methods deployed to monitor mosquito populations. To understand and interpret mosquito surveillance data, the frequency of use of malaria vector collection methods was analysed from a georeferenced vector dataset (> 10,000 data records), extracted from 875 manuscripts across Africa, the Americas and the Asia-Pacific region. Commonly deployed mosquito collection methods tend to target anticipated vector behaviours in a region to maximise sample size (and by default, ignoring other behaviours). Mosquito collection methods targeting both host-seeking and resting behaviours were seldomly deployed concurrently at the same site. A balanced sampling design using multiple methods would improve the understanding of the range of vector behaviours, leading to improved surveillance and more effective vector control

    Learning vector quantization and relevances in complex coefficient space

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    In this contribution, we consider the classification of time series and similar functional data which can be represented in complex Fourier and wavelet coefficient space. We apply versions of learning vector quantization (LVQ) which are suitable for complex-valued data, based on the so-called Wirtinger calculus. It allows for the formulation of gradient-based update rules in the framework of cost-function-based generalized matrix relevance LVQ (GMLVQ). Alternatively, we consider the concatenation of real and imaginary parts of Fourier coefficients in a real-valued feature vector and the classification of time-domain representations by means of conventional GMLVQ. In addition, we consider the application of the method in combination with wavelet-space features to heartbeat classification

    Identification and Characterization of a Small Molecule that Activates Thiosulfate Sulfurtransferase and Stimulates Mitochondrial Respiration

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    The enzyme Thiosulfate sulfurtransferase (TST, EC 2.8.1.1), is a positive genetic predictor of diabetes type 2 and obesity. As increased TST activity protects against the development of diabetic symptoms in mice, an activating compound for TST may provide therapeutic benefits in diabetes and obesity. We identified a small molecule activator of human TST through screening of an inhouse small molecule library. Kinetic studies in vitro suggest that two distinct isomers of the compound are required for full activation as well as an allosteric mode of activation. Additionally, we studied the effect of TST protein and the activator on TST activity through mitochondrial respiration. Molecular docking and molecular dynamics (MD) approaches supports an allosteric site for the binding of the activator, which is supported by the lack of activation in the E. coli. mercaptopyruvate sulfurtransferase. Finally, we show that increasing TST activity in isolated mitochondria increases mitochondrial oxygen consumption. This article is protected by copyright. All rights reserved.</p

    Endocannabinoid tone is higher in healthy lean South Asian than white Caucasian men

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    Diabetes mellitus: pathophysiological changes and therap

    Effect of sitagliptin on energy metabolism and brown adipose tissue in overweight individuals with prediabetes:a randomised placebo-controlled trial

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    Aims/hypothesis: The aim of this study was to evaluate the effect of sitagliptin on glucose tolerance, plasma lipids, energy expenditure and metabolism of brown adipose tissue (BAT), white adipose tissue (WAT) and skeletal muscle in overweight individuals with prediabetes (impaired glucose tolerance and/or impaired fasting glucose). Methods: We performed a randomised, double-blinded, placebo-controlled trial in 30 overweight, Europid men (age 45.9 \xc2\xb1 6.2\xc2\xa0years; BMI 28.8 \xc2\xb1 2.3\xc2\xa0kg/m2) with prediabetes in the Leiden University Medical Center and the Alrijne Hospital between March 2015 and September 2016. Participants were initially randomly allocated to receive sitagliptin (100\xc2\xa0mg/day) (n = 15) or placebo (n = 15) for 12\xc2\xa0weeks, using a randomisation list that was set up by an unblinded pharmacist. All people involved in the study as well as participants were blinded to group assignment. Two participants withdrew from the study prior to completion (both in the sitagliptin group) and were subsequently replaced with two new participants that were allocated to the same treatment. Before and after treatment, fasting venous blood samples and skeletal muscle biopsies were obtained, OGTT was performed and body composition, resting energy expenditure and [18F] fluorodeoxyglucose ([18F]FDG) uptake by metabolic tissues were assessed. The primary study endpoint was the effect of sitagliptin on BAT volume and activity. Results: One participant from the sitagliptin group was excluded from analysis, due to a distribution error, leaving 29 participants for further analysis. Sitagliptin, but not placebo, lowered glucose excursion (\xe2\x88\x9240%; p < 0.003) during OGTT, accompanied by an improved insulinogenic index (+38%; p < 0.003) and oral disposition index (+44%; p < 0.003). In addition, sitagliptin lowered serum concentrations of triacylglycerol (\xe2\x88\x9229%) and very large (\xe2\x88\x9246%), large (\xe2\x88\x9235%) and medium-sized (\xe2\x88\x9224%) VLDL particles (all p < 0.05). Body weight, body composition and energy expenditure did not change. In skeletal muscle, sitagliptin increased mRNA expression of PGC1\xce\xb2 (also known as PPARGC1B) (+117%; p < 0.05), a main controller of mitochondrial oxidative energy metabolism. Although the primary endpoint of change in BAT volume and activity was not met, sitagliptin increased [18F] FDG uptake in subcutaneous WAT (sWAT; +53%; p < 0.05). Reported side effects were mild and transient and not necessarily related to the treatment. Conclusions/interpretation: Twelve weeks of sitagliptin in overweight, Europid men with prediabetes improves glucose tolerance and lipid metabolism, as related to increased [18F] FDG uptake by sWAT, rather than BAT, and upregulation of the mitochondrial gene PGC1\xce\xb2 in skeletal muscle. Studies on the effect of sitagliptin on preventing or delaying the progression of prediabetes into type 2 diabetes are warranted. Trial registration: ClinicalTrials.gov NCT02294084. Funding: This study was funded by Merck Sharp & Dohme Corp, Dutch Heart Foundation, Dutch Diabetes Research Foundation, Ministry of Economic Affairs and the University of Granada

    The ischemic preconditioning effect of adenosine in patients with ischemic heart disease

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    <p>Abstract</p> <p>Introduction</p> <p><it>In vivo </it>and <it>in vitro </it>evidence suggests that adenosine and its agonists play key roles in the process of ischemic preconditioning. The effects of low-dose adenosine infusion on ischemic preconditioning have not been thoroughly studied in humans.</p> <p>Aims</p> <p>We hypothesised that a low-dose adenosine infusion could reduce the ischemic burden evoked by physical exercise and improve the regional left ventricular (LV) systolic function.</p> <p>Materials and methods</p> <p>We studied nine severely symptomatic male patients with severe coronary artery disease. Myocardial ischemia was induced by exercise on two separate occasions and quantified by Tissue Doppler Echocardiography. Prior to the exercise test, intravenous low-dose adenosine or placebo was infused over ten minutes according to a randomized, double blind, cross-over protocol. The LV walls were defined as ischemic if a reduction, no increment, or an increment of < 15% in peak systolic velocity (PSV) was observed during maximal exercise compared to the baseline values observed prior to placebo-infusion. Otherwise, the LV walls were defined as non-ischemic.</p> <p>Results</p> <p>PSV increased from baseline to maximal exercise in non-ischemic walls both during placebo (<it>P </it>= 0.0001) and low-dose adenosine infusion (<it>P </it>= 0.0009). However, in the ischemic walls, PSV increased only during low-dose adenosine infusion <it>(P </it>= 0.001), while no changes in PSV occurred during placebo infusion (<it>P </it>= NS).</p> <p>Conclusion</p> <p>Low-dose adenosine infusion reduced the ischemic burden and improved LV regional systolic function in the ischemic walls of patients with exercise-induced myocardial ischemia, confirming that adenosine is a potential preconditioning agent in humans.</p

    Human immunoglobulin G levels of viruses and associated glioma risk

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    Few consistent etiological factors have been identified for primary brain tumors. Inverse associations to asthma and low levels of varicella-zoster virus, immunoglobulin (Ig) levels in prevalent cases have indicted a role for the immune system in the development of glioma. Because samples from prevalent cases of glioma could be influenced by treatments such as steroids and chemotherapy, we investigated pre-diagnostic samples from three large Scandinavian cohorts. To test the hypothesis that immune response levels to these viruses are associated etiologically with glioma risk, we investigated pre-diagnostic immunoglobulin levels for cytomegalovirus (CMV), varicella-zoster virus (VZV), adenovirus (Ad), and Epstein-Barr virus (EBV) including the nuclear antigen (EBNA1) using plasma samples from 197 cases of adult glioma and 394 controls collected from population-based cohorts in Sweden and Denmark. Low VZV IgG levels were marginally significantly more common in glioma cases than the controls (odds ratio (OR) = 0.68, 95% CI 0.41–1.13) for the fourth compared with the first quartile (p = 0.06 for trend). These results were more prominent when analyzing cases with blood sampling at least 2 years before diagnosis (OR = 0.63, 95% CI 0.37–1.08) (p = 0.03). No association with glioma risk was observed for CMV, EBV, and adenovirus

    Relationship between Anaemia, Haemolysis, Inflammation and Haem Oxygenase-1 at Admission with Sepsis: a pilot study

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    Upregulation of haem oxygenase-1 (HO-1), due to haemolysis and/or inflammation, can lead to impaired immune function. Anaemia is common among sepsis patients, but the consequences of sepsis-associated anaemia are poorly understood. Here, our objective was to determine the prevalence and extent of anaemia, haemolysis, inflammation, and HO-1 induction after early hospital admission. We hypothesised that inflammation- or infection-induced haemolysis contributes to sepsis-associated anaemia and that this will lead to expression of HO-1. In this study, plasma obtained from seventy adult patients within 12 hours of admission to intensive care due to sepsis were analysed for anaemia, haemolysis and inflammatory markers by ELISA and microbead array. The majority (82.6%) of patients were anaemic with evidence of haemolysis (raised haem, haptoglobin, haemopexin, and HO-1 concentrations). Interestingly, concentrations of both haemoglobin and IL-10 were moderately positively correlated with HO-1 concentration (Hb: r = 0.32, p = 0.007; IL-10 r = 0.39, p = 0.0008) whereas HO-1 concentration was weakly negatively correlated with haemopexin (r = -0.23, p = 0.055). Anaemia, while common, was not associated with HO-1 concentration. After adjusting for confounding, HO-1 induction appears to be associated primarily with IL-10 concentration rather than haemolysis. Disease severity at diagnosis was correlated with early plasma IL-10 (r = 0.35, p = 0.003) and HO-1 (r = 0.24, p = 0.048) concentrations. Notably, admission levels of haem, HO-1, and IL-10 were indicators of survival

    Meer water met regelbare drainage?

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    Dit rapport geeft aan de hand van resultaten van vijf Nederlandse praktijkproeven inzicht in de mogelijkheden van regelbare of peilgestuurde drainage. Deze vorm van drainage - waarbij boeren de grondwaterstand op hun percelen flexibel kunnen regelen - houdt in tegenstelling tot conventionele drainage veel beter rekening met de uiteenlopende wensen en behoeften vanuit de landbouw, natuur, milieu en waterbeheer. Dit kan de realisatie van waterkwaliteits- en waterkwantiteitsdoelstellingen door waterschappen bevorderen en tegelijkertijd de bedrijfsvoering van agrariërs verbeteren
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