The purpose of this investigation was to correlate the viscoelastic properties and lipid fluidity of the red blood cell membrane to its lipid composition. The viscoelastic properties of human red cells that had been enriched or depleted in cholesterol were determined by the micropipette technique. The lipid fluidity of the outer and inner leaflets of the erythrocyte membrane was concurrently assessed by steady state fluorescence depolarization. The elastic modulus and the viscosity moduli of the erythrocyte membrane showed no significant differences between the cholesterol-modified and the control cells. Cholesterol enrichment decreased the lipid fluidity of the outer membrane leaflet alone, and cholesterol depletion increased the fluidity mainly of the inner leaflet.

To date, DNA-binding factors with a

Gemcitabine has substantial activity and acceptable toxicity in heavily pre-treated patients with advanced lymphoma. Further study is warranted.

The structure and functions of the human erythrocyte are influenced by the composition and organization of the membrane lipids. The outer (exofacial) and inner (endofacial) leaflets of the erythrocyte membrane differ in lipid composition, and recent studies using a group of membrane-impermeant pyrene fluorophores have demonstrated that the lipid fluidity of the outer leaflet exceeds that of the inner. Using one of these probes, pyrene butyryl hydrazide linked to the tetrasaccharide stachyose (SPBH), we have compared the lipid fluidity of the outer and inner leaflets in normal human erythrocytes treated experimentally to alter membrane cholesterol content and in acanthocytes, erythrocytes of altered morphology found in individuals with the genetic disorder abetalipoproteinaemia. The results, reported here, demonstrate that hemileaflet fluidity can be altered selectively: acanthocytosis and experimental cholesterol enrichment decrease the lipid fluidity of the outer but not the inner hemileaflet.

The incidence of non-HIV-associated hematologic malignancies, including chronic myeloproliferative disorders, is increasing in HIV-infected (HIV+) patients. This is thought to be due to prolonged survival in the era of highly active antiretroviral therapy (HAART). Previously, only six cases of chronic myeloid leukemia (CML) have been described in HIV+ individuals and limited information is available regarding the management of patients with concurrent CML and HIV-infection. We report three cases of CML in HIV+ patients who were treated with imatinib and HAART. Treatment was generally well tolerated, and cytogenetic response (complete in two patients) was achieved with follow-up ranging from 3 to 69 months. HIV viral load remained undetectable and CD4 cell counts were stable in all three patients. Concurrent treatment with imatinib and HAART can result in appropriate control of CML and HIV-infection as well as long-term survival.