[Single-donor protocol: Transfusion practices and multiple transfusion risk factors in neonatal intensive care unit]. / Protocole donneur unique : pratiques transfusionnelles et facteurs de risque des transfusions multiples en réanimation néonatale.

In France since 2002, the single-donor transfusion protocol, using four pediatric units from the same adult donor's packed red blood cells (PRBCs) in multiply transfused newborns, is recommended in preterm neonates to reduce the risks of infection and alloimmunization. This protocol is controversial, however, because it causes the transfusion of stored blood, which could have adverse consequences. Before the new recommendations of the French Haute Autorité de santé (National authority for health) in 2015, we conducted a national practice survey in 63 neonatal intensive care units (NICU) and a retrospective study of the characteristics of 103 children transfused within our unit, to better target beneficiaries. The practice survey showed that 30 % of French NICUs no longer used the protocol in 2014, due to logistical or financial problems, or concerns about the transfusion of stored blood. The practices were heterogeneous. Few NICUs used a written protocol. In our NICU, the use of single-donor protocol involved the use of units stored for more than 20 days in half of the cases beginning with the third unit used. Six-term newborns were mainly transfused once, which does not seem to warrant the single-donor transfusion protocol. The use of this protocol caused the loss of 50 % of the manufactured units, which go unused. In multivariate analysis, two factors were predictive of multiple transfusion within our population of 95 premature neonates undergoing transfusion: low-term and a high Clinical Risk Index for Babies (CRIB) score. The risk of multiple transfusions would be reduced by about 15 % for each additional week of gestation and approximately 16 % per point within the CRIB score. These variables integrated into a statistical model predict the risk of multiplying transfusions. According to the ROC curve, a calculated risk higher than 50 % is the appropriate cut-off value to transfuse with the single-donor transfusion protocol. This would limit its indications, saving more than 130 pediatric units of blood for 100 transfused children. A prospective study in our department will allow internal validation of this test.

A biodynamic model predicting waterborne lead bioaccumulation in Gammarus pulex: Influence of water chemistry and in situ validation.

Metals bioaccumulated in aquatic organisms are considered to be a good indicator of bioavailable metal contamination levels in freshwaters. However, bioaccumulation depends on the metal, the species, and the water chemistry that influences metal bioavailability. In the laboratory, a kinetic model was used to describe waterborne Pb bioaccumulated in Gammarus pulex. Uptake and elimination rate constants were successfully determined and the effect of Ca(2+) on Pb uptake was integrated into the model. Thereafter, accumulated Pb concentrations in organisms were predicted with the model and compared with those measured in native populations from the Seine watershed (France). The predictions had a good agreement with the bioaccumulation levels observed in native gammarids and particularly when the effect of calcium was considered. To conclude, kinetic parameters experimentally derived for Pb in G. pulex are applicable in environmental conditions. Moreover, the consideration of the water's chemistry is crucial for a reliable interpretation of bioaccumulation.

Modeling microbial competition in food: application to the behavior of Listeria monocytogenes and lactic acid flora in pork meat products.

Competition between background microflora and microbial pathogens raises questions about the application of predictive microbiology in situ, i.e., in non-sterile naturally contaminated foods. In this article, we present a review of the models developed in predictive microbiology to describe interactions between microflora in foods, with a special focus on two approaches: one based on the Jameson effect (simultaneous deceleration of all microbial populations) and one based on the Lotka-Volterra competition model. As an illustration of the potential of these models, we propose various modeling examples in estimation and in prediction of microbial growth curves, all related to the behavior of Listeria monocytogenes with lactic acid bacteria in three pork meat products (fresh pork meat and two types of diced bacon).