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M Auffret

Publications and source records attributed to M Auffret.

10 recordsLinked to original sources
PubMed2005

Myelotoxicity of trichothecenes and apoptosis: an in vitro study on human cord blood CD34+ hematopoietic progenitor.

Previous studies have revealed that hematological disorders associated with trichothecenes intoxication in humans could result from hematopoiesis inhibition. The most frequent and potent trichothecene mycotoxins are T-2 toxin and deoxynivalenol (DON), respectively. Apoptosis induction by these two toxins was investigated in vitro on human hematopoietic progenitors (CD34+ cells). Hoechst coloration, DNA fragmentation and annexin-V/PI labeling in flow cytometry showed that T-2 toxin, in contrast to DON, induced apoptosis in CD34+ cells. T-2 toxin effect was dose- and time-dependent with a significant increase of apoptotic cells as early as 3h after incubation at 10(-7) M and a maximum reached at 12 h. This observation evidenced the high sensitivity of hematopoietic progenitors to T-2 toxin. The inhibition of T-2 toxin-induced apoptosis by a pan-caspase inhibitor (Z-VAD-fmk) suggested the involvement of caspases. The proportional increase of caspase-3 specific activity (DEVDase) with T-2 toxin concentration confirmed its role in the process. After incubation of CD34+ cells with T-2 toxin, in conditions that induced apoptosis, clonal expansion of granulo-monocytes, erythrocytes and megakaryocytes precursors was dose-dependently inhibited. The hematological effects observed in T-2 toxin mycotoxicosis could then be assigned to hematopoiesis inhibition by apoptosis. Different mechanisms that need to be further elucidated are involved in DON myelotoxicity.

Antigens, CD34↗
PubMed2005

[Venous ulcer on the hand due to a treatment-related arteriovenous fistula].

BACKGROUND: An arteriovenous fistula of the arm for hemodialysis needs to last long and provide easy access for puncture. CASE-REPORT: A 50 year-old woman, with type 2 diabetes complicated by chronic renal failure, presented with an ulcer on the dorsum of the right hand that had developed over the past year. Humeral artery to basilica vein, side-to-side, arteriovenous fistula in the right arm was created in 1996. In 1999, she received a renal transplant. In 2002, she developed a deep ulcer on the dorsum of the right hand that progressed over one year, without improvement good local treatment. Doppler echography and a fistulography revealed proximal stenosis of the basilica vein, and a less restricted distal stenosis before the shunt. A venous ulcer on the dorsum of the hand due excessive venous pressure in the draining area. DISCUSSION: The complications of arteriovenous fistulas can be severe. Arterial stenosis is frequent and is the consequence of intimal hypertrophy. Chronic ischemia symptoms can be observed, but the hemodynamic loss is usually asymptomatic. When clinical signs are noisy emergency surgery is required. Venous stenosis is responsible for ischemia through venous overload, leading to edema of the arm, and rarely to venous-ulcer type trophic disorders as seen in this patient. Screening for stenosis on the vascular vein network must be systematic before creating an arteriovenous fistula.

Arteriovenous Shunt, Surgical↗
PubMed2000

Alterations in hemolymph and extrapallial fluid parameters in the Manila clam, Ruditapes philippinarum, challenged with the pathogen Vibrio tapetis.

In a recent study, we demonstrated the presence of defense factors, competent hemocytes and high enzymatic activities (peptidases, hydrolases, lytic, etc.), in the extrapallial fluid, located between the mantle and the shell, of the Manila clam, Ruditapes philippinarum. In Europe, this species is affected by brown ring disease, an epizootic disease caused by the bacterium Vibrio tapetis. The present work focused on the effect of the development of the disease on cellular and humoral defense parameters in the hemolymph and the extrapallial fluid of experimentally infected clams. Results indicate significant changes in total and dead hemocyte counts, as well as modifications in lysozyme activity and protein content, in the hemolymph and extrapallial fluid of challenged animals. Hemocyte counts and lysozyme activity increased significantly in the hemolymph, but particularly in the extrapallial fluid, where the highest values were observed. A healing (recalcification) process was observed 7 weeks following challenge, suggesting defense system efficiency at neutralizing the pathogen. These results are discussed with emphasis on the role of extrapallial fluids in the defense process against invading microorganisms.

Animals↗
PubMedDate not supplied

Genetic responses to metal contamination in two clams: Ruditapes decussatus and Ruditapes philippinarum.

Coastal ecosystems are subjected to a wide variety of disturbances, including those due to xenobiotics of agricultural and industrial origin. These pollutants as heavy metals can modify the genetic diversity of populations by favouring or counter-selecting certain alleles or genotypes by differential mortality. In the present study, two genetic markers (phosphoglucomutase and glucosephosphate isomerase) and a protein marker (metallothionein) were monitored in order to determine the impact of heavy metals in different clam populations. Analysis of the genetic structure of the clam populations examined reveals that those inhabiting environments contaminated by heavy metals exhibit a higher allelic diversity and possess alleles at PGM loci that could be selected by the presence of heavy metals. The evaluation of metallothionein levels using a specific polyclonal antibody developed in the Pacific oyster (Crassostrea gigas) demonstrated the existence of a relationship between metallothionein concentrations and the level of metal pollution for clam populations sampled from different sites. An inter-specific difference was also detected between Ruditapes decussatus and Ruditapes philippinarum living in sympatry at the same site, suggesting a differential response of these two species upon exposure to an identical heavy metal concentration.

Adaptation, Physiological↗
PubMedDate not supplied

Assessment of ejection fraction with Tl-201 gated SPECT in myocardial infarction: Precision in a rest-redistribution study and accuracy versus planar angiography.

BACKGROUND: Viability and left ventricular ejection fraction (LVEF) are essential measures for the assessment of myocardial infarction (MI). These 2 variables may be evaluated simultaneously by means of thallium-201 gated single photon emission computed tomography (SPECT); however, the precision and accuracy of LVEF measurements with this isotope remain controversial, particularly in cases of extended perfusion defects and poor count densities. METHODS AND RESULTS: Fifty patients with a history of MI underwent a 20-minute rest and a 4-hour redistribution Tl-201 gated SPECT viability protocol, immediately followed by a technetium-99m planar equilibrium radionuclide angiography (ERNA). On gated SPECT images, various count statistics were calculated, and perfusion was automatically quantified by means of CardioMatch, which provided both the size and severity of MI defects. Rest and redistribution LVEFs were determined from gated SPECT with Germano's algorithm, whereas LVEFs were calculated from ERNA using the manufacturer's software. Mean LVEF values calculated with rest gated SPECT, redistribution gated SPECT, and planar ERNA were 30% +/- 13%, 30% +/- 13% and 33% +/- 13%, respectively. Significant differences between repeated gated SPECT LVEFs were not shown by means of the paired t test. Correlation coefficients were high between 20-minute and 4-hour scans (r = 0.89) and between gated SPECT and ERNA (r = 0.88 and r = 0.92 at 20 minutes and 4 hours, respectively). Additionally, close agreement between gated SPECT and ERNA was shown by means of the Bland-Altman plot, despite an underestimation of 3 units. Finally, neither the technical conditions (count density, heart rate, lung uptake, etc) nor the perfusion alteration (size, severity, redistribution) appeared to interfere with the precision and accuracy of gated SPECT LVEF measurement. CONCLUSION: Tl-201 gated SPECT is a precise method for assessing LVEF within the same patient at 4-hour intervals, even with a substantial count decay, and it gives accurate results compared with planar ERNA, even in the case of large perfusion defects.

Adult↗