Long-term viral competition monitoring: a case of epidemiological rescue

Biological invasions are major threats to biodiversity and the main causes of emerging viral diseases. The ongoing spread of Tomato yellow leaf curl virus is a major concern to the sustainable tomato production throughout the world. The two main strains of TYLCV have been successively introduced in Reunion Island providing a fortuitous field experiment to study the invasion and competition of these two emerging strains in a tropical and insular environment. In this study, a seven-year field survey was performed following the introduction of the Israel strain of TYLCV (TYLCV-IL) into a niche occupied by the Mild strain of TYLCV (TYLCV-Mld). A displacement of the resident TYLCV-Mld by the newcomer TYLCV-IL was observed in this short period. To understand the factors associated with this displacement, biological traits related to fitness were measured to compare these strains. Besides demonstrating a better ecological aptitude of TYLCV-IL, which explains its rapid spread and increasing prevalence, the first estimate of the number of viral particles efficiently transmitted by an insect vector for a circulative virus was obtained. However, TYLCV-Mld persistence in the field (especially in mixed infections with TYLCV-IL) spurred further experiments regarding the effects of the mixed infections on these biological traits. Our study revealed complex interplay between these two strains of one of the most emergent plant virus following their successive introductions in the insular and tropical environment of Reunion Island. This rare case of unilateral facilitation between two pathogens led to the epidemiological rescue and maintenance of the less fit strain. (Texte intégral

Morphological Filtering and Granulometric Analysis on Scanning Electron Micrographs: Applications in Materials Science

For many applications, scanning electron microscopy (SEM) images reflect the granular texture of analysed objects. So it is important to characterise the morphology of this texture and also to filter these images. Because the size of the texture is the main criterion to be studied, we have focused our paper on granulometric analysis. We present basic parameters, morphological filtering and granulometry for Rn•R functions and their properties with local knowledge and anamorphosis. Some applications in the domain of materials science illustrate these methods and present their suitable possibilities

P-621: Metabolic determinants of proximal sodium reabsorption in healthy women

Increased reabsorption of sodium (Na) in the proximal segments of the nephron is present in hypertensive patients. Studies performed in men reported an association between proximal Na reabsorption and features of the metabolic syndrome. This study explores the relationship between metabolic variables and proximal Na reabsorption in healthy women. This study is population-based and cross-sectional examining 661 healthy women aged 40-75y. After 15 minutes rest, blood pressure was measured 3 times, blood was drawn and urine was collected. Fractional excretion of endogenous lithium (FELi) was used as an indirect marker of proximal sodium reabsorption, lithium being only reabsorbed in the proximal tubule. All women receiving blood pressure, blood glucose or lipid lowering therapy were excluded. Correlations: FELi was positively correlated with the fractional excretion of sodium (FENa, r=0.3, p<0.001). FELi was negatively associated with total cholesterol (r=-0.14, P<0.0001), LDL-cholesterol (r=-0.16, P<0.0001), BMI (r=-0.08, P<0.05) and weight (r=-0.09, P<0.05). Menopausal status or a family history of hypertension did not affect the associations. Simple linear regression analysis: age, waist circumference, waist/hip ratio, systolic blood pressure, diastolic blood pressure, Hdl cholesterol, triglycerides, serum uric acid or a family history of hypertension were not significant predictors of FELi. BMI was a significant predictor but the strongest relationships were found between FELi and total cholesterol, LDL-cholesterol and FENa. Multivariate linear regression model: When significant predictors of FELi were examined in a multivariate linear regression model also controlling for age, weight, systolic blood pressure and FENa, total cholesterol (p=0.003) or LDL-cholesterol (p=0.001) significantly and independently predicted FELi. In conclusion, these data suggest that metabolic parameters, in particular total cholesterol and LDL-cholesterol and to a lesser extent weight and BMI, are associated with increased proximal Na reabsorption in a healthy untreated women population. Considering the possible link between increased reabsorption of sodium and the development of hypertension, a major cardiovascular risk factor, this association may provide an additional hypothesis for the increased cardiovascular risk of subjects with the metabolic syndrom

Cholesterol lowering effect of a soy drink enriched with plant sterols in a French population with moderate hypercholesterolemia

<p>Abstract</p> <p>Background</p> <p>Plant sterols are an established non-pharmacological means to reduce total and LDL blood cholesterol concentrations and are therefore recommended for cholesterol management by worldwide-renown health care institutions. Their efficacy has been proven in many types of foods with the majority of trials conducted in spreads or dairy products. As an alternative to dairy products, soy based foods are common throughout the world. Yet, there is little evidence supporting the efficacy of plant sterols in soy-based foods. The objective of this study was to investigate the effect of a soy drink enriched with plant sterols on blood lipid profiles in moderately hypercholesterolemic subjects.</p> <p>Methods</p> <p>In a randomized, placebo-controlled double-blind mono-centric study, 50 subjects were assigned to 200 ml of soy drink either enriched with 2.6 g plant sterol esters (1.6 g/d free plant sterol equivalents) or without plant sterols (control) for 8 weeks. Subjects were instructed to maintain stable diet pattern and physical activity. Plasma concentrations of lipids were measured at initial visit, after 4 weeks and after 8 weeks. The primary measurement was the change in LDL cholesterol (LDL-C). Secondary measurements were changes in total cholesterol (TC), non-HDL cholesterol (non-HDL-C), HDL cholesterol (HDL-C) and triglycerides.</p> <p>Results</p> <p>Regular consumption of the soy drink enriched with plant sterols for 8 weeks significantly reduced LDL- C by 0.29 mmol/l or 7% compared to baseline (p < 0.05). TC and non-HDL-C concentrations decreased by 0.26 mmol/l and 0.31 mmol/l (each p < 0.05), respectively. Mean reductions in total, LDL and non-HDL cholesterol were significantly greater than in the placebo group (p < 0.05). HDL-C and triglycerides were not affected. Compliance was very high (>96%), and products were well tolerated.</p> <p>Conclusion</p> <p>Daily consumption of a plant sterol-enriched soy drink significantly decreased total, non-HDL and LDL cholesterol and is therefore an interesting and convenient aid in managing mild to moderate hypercholesterolemia.</p

Step Count is Associated With Lower Nighttime Systolic Blood Pressure and Increased Dipping

BACKGROUND Higher nighttime blood pressure (BP) and the loss of nocturnal dipping of BP are associated with an increased risk for cardiovascular events. However, the determinants of the loss of nocturnal BP dipping are only beginning to be understood. We investigated whether different indicators of physical activity were associated with the loss of nocturnal dipping of BP. METHODS We conducted a cross-sectional study of 103 patients referred for 24-hour ambulatory monitoring of BP. We measured these patients' step count (SC), active energy expenditure (AEE), and total energy expenditure simultaneously, using actigraphs. RESULTS In our study population of 103 patients, most of whom were hypertensive, SC and AEE were associated with nighttime systolic BP in univariate (SC, r = -0.28, P < 0.01; AEE, r = -0.20, P = 0.046) and multivariate linear regression analyses (SC, coefficient beta = -5.37, P < 0.001; AEE, coefficient beta = -0.24, P < 0.01). Step count was associated with both systolic (r = 0.23, P = 0.018) and diastolic (r = 0.20, P = 0.045) BP dipping. Nighttime systolic BP decreased progressively across the categories of sedentary, moderately active, and active participants (125mm Hg, 116mm Hg, 112mm Hg, respectively; P = 0.002). The degree of BP dipping of BP increased progressively across the same three categories of activity (respectively 8.9%, 14.6%, and 18.6%, P = 0.002, for systolic BP and respectively 12.8%, 18.1%, and 22.2%, P = 0.006, for diastolic BP). CONCLUSIONS Step count is continuously associated with nighttime systolic BP and with the degree of BP dipping independently of 24-hour mean BP. The combined use of an actigraph for measuring indicators of physical activity and a device for 24-hour measurement of ambulatory BP may help identify patients at increased risk for cardiovascular events in whom increased physical activity toward higher target levels may be recommende