Analytical validation of the new plasma calibrated Accu-Chek (R) Test Strips (Roche Diagnostics)

peer reviewedBackground: The Accu-Chek Inform glucose monitor is a point-of-care system for testing blood glucose. New test strips, calibrated to deliver glucose plasma-like values, were launched on the market in May 2005. The aim of our study was to perform analytical validation of these new strips. Methods: We compared the new plasma strips with whole blood strips; results for the plasma strips with plasma values obtained using a clinical analyzer and with whole blood values given by the glucose electrode of a blood gas analyzer; and the influence of the type of blood (capillary or venous) on the results obtained by the glucose monitor with the plasma calibrated strips. Results: Plasma strips give on average 7% higher results than the previous whole blood strips. However, the results given by the plasma strips on capillary whole blood, even if well correlated, are not completely comparable with those given by an analyzer for venous plasma. Nevertheless, these plasma strips and the glucose electrode of a blood gas analyzer give comparable results. Conclusions: Accu-Chek Inform plasma strips are a good method for monitoring of blood glucose values in patients with diabetes

analytical and Clinical Validation of Beta-Trace Protein, a New Marker of Glomerular Filtration Rate

Peer reviewe

Analytical Verification of the IDS-iSYS Intact Amino-terminal Propeptide of Type 1 Procollagen (P1NP)

Peer reviewe

Validation of the Abbott Architect 25(OH)-vitamin D assay

peer reviewe

Impact of different endurance races on the heart: the point of view of the biologist

peer reviewedObjective The aim of this study was to investigate the impact of intense exercise, represented by different endurance races, in relationship with oxidative stress and cardiac markers. In a second time, we tried to demonstrate if oxidative stress induced by physical activity is a physiological or pathological process, and to establish some issues to diagnose the risk of sudden death in athletes. Methods Four populations were compared, a control group of 16 participants “sedentary” (37 ± 4,39 years old), a group of 24 semi-marathon runners (41 years ± 8,76 years old), a group of 28 marathon runners (44,1 ± 8,37 years old) and a group of 33 ultra-trail runners (45,8 ± 8,7 years old). Three blood tests were drowned, one just before, one just after, and the last three hours after the end of the race.Different oxidative and stress and cardiac biomarkers were measured. The ultra-trail runners will be subject to an echocardiography and an ECG pre- and post-race. For statistical analysis, STATISTICA 10 software was used. We performed a non-parametric test of Kruskal-Wallis for independent sample and a Friedman ANOVA for paired samples. Results Myeloperoxydase increased during exercise, but the release is less important according to the level of training of the runners. GSH/GSSG ratio seems to remain stable during the race but it could increase during the 24 hours post-race. There is a decrease in lipidic peroxidation during exercise. But, we note an increase of creatine kinase, isoform MB, myoglobin and C-reactive protein during the race. We observe an increase of troponin T and natriuretic peptide but with a different kinetic than the kinetic obtained for a myocardial infarction. Medical imaging in ultra-trail runners present cardiac adaptations to endurance training, as left ventricular hypertrophy (LVH) and incomplete right bundle branch block (IRBBB). A decrease of systolic and diastolic volumes of the left ventricle and a decrease of longitudinal strain were observed by echocardiography at the end of the race. Conclusion Endurance races induce the income of oxidative stress objectified by different biomarkers increase, but a cell necrosis is not specially observed. In fact, the increase of the cardiac markers during endurance races but may be explained by a transient modification of myocyte permeability, with a release of pool cytosolic. These races may induce micro-muscle damages causing the appearance of an inflammatory process explaining our observations of markers of inflammation. For the medical imaging, it was observed a myocardial adaptation to training and a transient impairment of ventricular function due to dehydration

Is cystatin C useful for the detection and the estimation of low glomerular filtration rate in heart transplant patients?

Although previously studied in patients with chronic kidney disease, there is less data for the use of cystatin C and cystatin C-based formulas in heart transplant recipients. The ability of creatinine and cystatin C to detect renal failure (glomerular filtration rate [GFR] below 60 mL/min/1.73 m(2)) in heart transplant patients has been compared. The accuracy and precision of a creatinine-based formula (Modification of Diet in Renal Disease [MDRD]) versus a cystatin C-based formula (Rule's formula) to estimate GFR have also been studied. GFR was measured using the (51)Crethylenediamine tetraacetic acid tracer in 27 patients. There was no significant difference between GFR and the reciprocal of creatinine or cystatin C. Receiver operating characteristic curves for cystatin C and creatinine were similar. Both formulas were well correlated with the GFR. The bias of the cystatin C-based was significantly better than one of the MDRD formula, but the standard deviation appeared better for the MDRD formula (bias of +3.9 mL/min/1.73 m(2) versus +12 mL/min/1.73 m(2) and SD of 8.5 versus 11.6, respectively). Plasma cystatin C has no clear advantage over serum creatinine to detect renal failure in heart transplanted patients

Visualizing Compaction of Polysomes in Bacteria.

International audienceDuring protein synthesis, many translating ribosomes are bound together with an mRNA molecule to form polysomes (or polyribosomes). While the spatial organization of bacterial polysomes has been well studied in vitro, little is known about how they cluster when cellular conditions are highly constrained. To better understand this, we used electron tomography, template matching, and three-dimensional modeling to analyze the supramolecular network of ribosomes after induction of translational pauses. In Escherichia coli, we overexpressed an mRNA carrying a polyproline motif known to induce pausing during translation. When working with a strain lacking transfer-messenger RNA, the principle actor in the "trans-translation" rescuing system, the cells survived the hijacking of the translation machinery but this resulted in a sharp modification of the ribosomal network. The results of our experiments demonstrate that single ribosomes are replaced with large amounts of compacted polysomes. These polysomes are highly organized, principally forming hairpins and dimers of hairpins that stack together. We propose that these spatial arrangements help maintain translation efficiency when the rescue systems are absent or overwhelmed