Functional regions of the envelope glycoprotein of human immunodeficiency virus type 1.

The envelope of the human immunodeficiency virus type 1 (HIV-1) plays a central role in the process of virus entry into the host cell and in the cytopathicity of the virus for lymphocytes bearing the CD4 molecule. Mutations that affect the ability of the envelope glycoprotein to form syncytia in CD4+ cells can be divided into five groups: those that decrease the binding of the envelope protein to the CD4 molecule, those that prevent a post-binding fusion reaction, those that disrupt the anchorage of the envelope glycoprotein in the membrane, those that affect the association of the two subunits of the envelope glycoprotein, and those that affect post-translational proteolytic processing of the envelope precursor protein. These findings provide a functional model of the HIV envelope glycoprotein.

Cis-acting sequences responsive to the rev gene product of the human immunodeficiency virus.

Expression of high levels of the structural proteins of the human immunodeficiency virus type 1 (HIV-1) requires the presence of two regulatory genes, the trans-activator (tat), and the regulator of virion protein expression (rev. previously called art or trs). The experiments described here show that expression of virion proteins is dependent upon a small region located in the envelope gene called the cis-acting antirepression sequence (CAR). The CAR region of the envelope sequence is both necessary and sufficient for rev-dependent capsid protein expression. The experiments also show that a defect in either rev or CAR results in a dramatic decrease in the accumulation of the genomic and envelope mRNAs and an overproduction of more extensively spliced viral mRNA species.

Engraftment and outcomes of patients receiving myeloablative therapy followed by autologous peripheral blood stem cells with a low CD34+ cell content.

Engraftment kinetics after high-dose chemotherapy (HDC) were evaluated in patients receiving autologous peripheral blood stem cell (PBSC) infusions with a low CD34+ cell content. Forty-eight patients were infused with < 2.5 x 10(6) CD34+ cells/kg; 36 because of poor harvests and 12 because they electively received only a fraction of their harvested cells. A median of 2.12 x 10(6) CD34+ cells/kg (range, 1.17-2.48) were infused following one of seven different HDC regimens. All patients achieved absolute neutrophil counts > or = 0.5 x 10(9)/l at a median of day 11 (range, 9-16). Forty-seven patients achieved platelet counts > or = 20 x 10(9)/l at a median of day 14 (range, 8-250). Nine of 47 (19%) had platelet recovery after day 21, 4/47 (9%) after day 100 and one died on day 240 without platelet recovery. Twenty-six patients (54%) died of progressive disease in 51-762 days; 22 (46%) are alive at a median of 450 days (range, 94-1844), 17 (35%) of whom are surviving disease-free at a median of 494 days (range, 55-1263). No patient died as a direct consequence of low blood cell counts. These data demonstrate that PBSC products containing 1.17-2.48 x 10(6) CD34+ cells/kg resulted in relatively prompt neutrophil recovery in all patients but approximately 10% had delayed platelet recovery.

Metastatic prostatic adenocarcinoma within a primary solid papillary carcinoma of the male breast.

We report the case of a 78-year-old man who developed a breast mass 12 months after hormonal therapy for palliation of prostatic adenocarcinoma. On histologic and immunohistochemical examination, the breast tumor revealed a unique collision tumor composed of metastatic prostatic adenocarcinoma and solid papillary breast carcinoma.