[Avascular necrosis of the femoral head in children with sickle cell disease (Libreville, Gabon)].

We present the clinical aspects of avascular osteonecrosis in children with sickle-cell disease and emphasize the need for early detection of this necrosis of the femoral head, which is often nearly or totally asymptomatic. This retrospective descriptive study covers the 10 years from January 1989 through December 1999 and includes 22 homozygous (Hb-SS) children and adolescents with sickle-cell disease, all presenting pain in the hip and/or limping. The sex ratio was 2.

Arachidonic acid metabolism of rat peritoneal macrophages after passive sensitization and allergen challenge.

The aim of our work was to evaluate the effect of passive sensitization of rat peritoneal macrophages (treatment of cells by an anti-ovalbumin IgE-rich serum) on arachidonic acid (AA) metabolism and the impact of specific antigen (ovalbumin) on this process. Compared to a control treatment without serum, the atopic serum and a serum without IgE, used on [3H]AA-labeled macrophages, increased cyclooxygenase and lipoxygenase eicosanoid production. Sera, used prior to [3H]AA incorporation, induced a decrease of 3H-labeled membrane phospholipids and an increase of lipoxygenase metabolites in the [3H]AA incorporation medium.

Eicosanoid production by mouse peritoneal macrophages during Toxoplasma gondii penetration: role of parasite and host cell phospholipases.

The metabolism of endogenous arachidonic acid by mouse resident peritoneal macrophages infected in vitro with Toxoplasma gondii was studied. Prelabeling of macrophages with [5,6,8,9,11,12,14,15-3H]arachidonic acid and challenge with tachyzoites for 15 min resulted in a high mobilization of free labeled arachidonic acid (178%) in the culture medium. The parasites also triggered the synthesis of 6-keto-prostaglandin F1 alpha (47%), prostaglandin E2 (44%), leukotrienes C4 and D4 (33%) and 5-, 12-hydroxyeicosatetraenoic acids (155%).