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Aim. Although an increase in volume of the legs during prolonged standing is a well-known phenomenon, there is little information on the initial phase in orthostasis. The aim of this study is to measure the increase in volume and its distribution in the lower extremities during orthostatic stress in healthy and varicose patients.Methods. In this prospective study volume changes of the legs in 16 healthy individuals and 24 patients with varicose veins were investigated using an optoelectric volume measurement system (Perometer (R)) during 10 minutes in a standing position.Results. We could show that during a 10 minute standing experiment, a significant increase in volume of the entire leg, in both the healthy vein group (2.48%) and the varicose group (2.1%) occurred. Significant volume increase appeared in the upper and lower leg respectively. No significant differences could be demonstrated between right and left leg or between healthy and varicose legs.Conclusion. These results in accordance with other published data indicate that changing position from lying or sitting to standing initially leads to a rapid increase in volume of the leg. These changes take place very quickly and with respect to their volume changes, are significant. The volume increase is following a bi-exponential function fitting to a fast filling compartment (venous pooling) and a slow filling compartment reflecting extravasation. Over the course of the day additional edema formation may occur. [Int Angiol 2010;29:395-400]

cited By 1; International audience; More and more attention is given to the measurement of arsenic and selenium in natural waters. Total analysis is not sufficient to understand their environmental impact which has to be related to their chemical forms. Speciation analysis is thus necessary. ICPMS (inductively coupled plasma - mass spectrometry) is the detector of choice in environmental analysis, and its coupling with high performance liquid chromatography (HPLC) is easily achieved. However, the ICPMS detection of As and Se can suffer from argon based interferences. In the last past years, ICPMS equipped with collision/reaction cell system have been developped. The addition of one or several gas in the system permit the removal of these interferences. Flow rates of hydrogen and helium were carefully optimised to remove efficiently the interferences on m/z 75 and 80, while keeping maximum sensitivity. A mixture of 3.8 ml min -1 of H2 and 0.5 ml min-1 of He was selected as the most appropriate for As and Se determination. These conditions were found to be also suitable for speciation analysis. Analytical performances were calculated with this set of conditions for elemental and speciation analysis (separation of organic and inorganic Se on the one hand, and inorganic As and Se on the other hand). Detection limits are close to 30 ng(elt) l-1 for both elements in total analysis and in the range 100-200 ng(elt) l-1 for speciation analysis depending of the species. These results represent a 3 fold improvement in comparison with standard mode (C/RC switched off). Accuracy of the method was tested using a reference material (TMRain-95, National Water Research Institute, Canada) and different mineral waters were analysed.

cited By 0; International audience; Selenium is today recognized as a trace element, it is thus essential to life, but in higher doses it becomes toxic for Human and animals. The concentration range between its indispensable role and its toxicity is very narrow. Selenium appears in its natural cycle in several oxidation states and as a variety of inorganic and organic compounds. In waters, selenite and selenate are the species most often searched and detected. It has been shown that inorganic selenium doesn't always account for total concentration in water. Therefore identification and quantification of dissolved organic species, i.e selenomethionine, selenocystine, trimethylselenonium..., is essential to complete selenium speciation. Our lab is interested since 1991 in selenium environmental chemistry in aquatic systems. Attention is paid here to our recent analytical developments based on high performance liquid chromatography - inductively coupled plasma mass spectrometry (HPLC-ICPMS), allowing environmental speciation at the ten ng (Se). L-1 level. We focus on two ways to lower Se detection limits. On the one hand, detector performances are improved with the help of recent ICPMS generation equipped with collision/reaction cell, operating conditions being optimized by experimental design methodology. Sample introduction by hydride generation step instead of pneumatic nebulisation, also results in improved detection power. On the other hand, we are developping preconcentration procedures to artificially lower detection limits. We select working stationary phases that allow the simultaneous preconcentration of inorganic and organic selenium species to keep the advantage of HPLC-ICPMS direct speciation.