Evaluation of Hemoglobin Saturation During Sleep in Children With Sickle Cell Disease

Abstract

a-Thrombin, a serine protease with potent procoagulant activity, has the capacity to stimulate the proliferation of fibroblasts, vascular endothelial cells and macrophages. However, for the latter cell type, esterolytically intact enzyme is not required and, in fact, the mitogenic potency of the molecule appears to reside in a limited unique region of thrombin termed the 8-loop peptide (B-LP). In an attempt to determine the mechanism by which B-LP mediates mitogenesis, B-LP sensitive 5774.1 macrophage cells were fixed in paraformaldehyde and incubated for 1 hr with lZ51 BzLP in the presence and absence of exogenous unlabeled ligand (10 'O-l0-~)(n=5).The data show that the 5744.1 cells possess a specific, saturable B-LP receptor that exhibits a Kd of -1.12 nM; a value that coincides with the concentration of peptide necessary to optimally elicit a mitogenic response in these cells. Native a-thrombin, inactivated DIPthrombin and unlabeled B-LP displace bound lZ5-labeled B-LP from 5774 cells at equimolar concentrations suggesting that all the 3 peptides interact with a common receptor site on macrophages.Scatchard analysis indicates that -4000 such receptors are present per cell. We suggest that ligand activation of these receptors is responsible for triggering the biological response associated with thrombin-stimulated macrophages, and therefore, is likely pivotal in promoting the accumulation of these cells during the processes of inflammation and wound healing. Table). IOSS OF HEPATITlSEvidence of HBsAb (n=37) or exposure to hepatitis vaccine (n=10) was found in 87% of HTLV-111 positive patients at some time during their care i n our clinic. However, 17% demonstrated subsequent antibody loss and/or did not respond to hepatitis vaccine. This unusual HBsAb response was restricted to patients < 17 years of age (63% of all patients). This result contrastFd to only a 2% loss of HBsAb or vaccine non-response in the HTLV-111 negative patients who had previously been positive for HBsAb (n=24) or were given the hepatitis vaccine (n=16). This result suggests that loss or a1 teration of hepatitis B immunity in children occurs as a result of HTLV-I11 infection or exposure. The hematologic manifestations of 100 pediatric patients with AIDSIARC were reviewed. Acute or chronic anemia was present in 94% of all patients. Two patients had autoimmune hemolytic anemia and 1 patient had an aplastic anemia. A positive Coombs test was detected in 40% of all patients. Leukopenia and neutropenia occurred in 50% and 40% of patients respectively. Antineutrophil antibodies were detected in 2 patients. Ten of 13 children developed neutropenia on Bactrim. Forty percent of all children were lymphopenic. Monocytosis and eosinophilia occurred in 66% and 40% of patients respectively. Thrombocytopenia was seen in 33% and of these 25% developed a persistent thrombocytopenia. Platelet antibodies were detected in 10 of 11 patients. Pancytopenia occurred in 20% of children with opportunistic infection (0.1.).Acquired Von Willebrands disease and auto...