[Scintigraphic imaging of macrophages involved in lung vasoreflex: rat model]. / Scintigraphie des macrophages impliqués dans la vasoréactivité pulmonaire: modélisation chez le rat.

At time of pathological situations, a pulmonary fixation of labelled substances injected by intravenous way is observed. This fixation would result from a phagocytosis of these substances by abnormal cells whose presence was induced in the endothelium: Pulmonary Intravascular Macrophages (PIM's). After activation by phagocytosis, these cells are able to secrete powerful vasoactive mediators capable of inducing cardiopulmonary accidents. Hepatic cholestase was induced in Wistar rats by ligation and section of common bile duct. The recruitment of PIM's was followed in vivo by phagocytosis scintigraphic imaging after labelled colloid injection. During the 35 days of evolution of the pathology, we observe a pulmonary fixation of the colloid agents which progresses up to 70% as well as a concomitant decease in the hepatic activity. Histologic examination showed numerous cells related to pulmonary capillaries' endothelium belonging to mononuclear phagocytes line and expressing an activated phenotype of monocytes. The scintigraphic and histological tests carried out enabled us to validate the model of induction of PIM's in rat by ligation of the choledoque one. The study of the vasoactive response via certain mediators can from now be approached, a Doppler technique on the pig aorta is being in the course of evaluation.

[Sickle cell disease neonatal screening. First evaluation]. / Dépistage néonatal de la drépanocytose au CHU de Dakar: premier bilan.

A neonatal screening allows a preclinical diagnosis of major sickle cell syndromes and an early management of the affected children. That would improve their life quality and expectancy. The preliminary program was set up on 518 senegalese newborn aged from 1 to 4 days, and coming from all the country ethnic groups. Isoelectrofocalisation is the test used on dried blood eluate and the positive control on citrate agar gel. 478 samples out of 518 (92.5%) have been analysed. Haemoglobinopathy have been found in 11.1% of cases, distributed as follow: heterozygoty FAS and FAC: 9%, double heterozygoty FSC: 0.2% and homozygoty FSS: 1.9%. Sickle cell neonatal screening should be imperatively implemented, with regards in economical considerations. It would be relevant to integrate it in a larger program including information, training and genetic counselling in order to avoid homozygotes birth and to lower the spread of this disease.