Development of a single-shot subunit vaccine for HIV-1. 2. Defining optimal autoboost characteristics to maximize the humoral immune response

The design of a single-shot subunit vaccine for HIV-1 with polylactic-coglycolic acid (PLGA) sustained-release technology to effect an autoboost of antigen (MN gp120) at a given time after the primary immunization requires in-depth knowledge about the timing, the duration, and the need for coadjuvant in the autoboost. These questions cannot be answered unambiguously with PLGA microspheres, so we have conducted studies using Alzet minipumps to release antigen at prescribed times to mimic a PLGA autoboost. The results show that a discrete autoboost is preferred over continuous release of antigen, that the time profile of the autoboost (whether pulsatile or a 2-week continuous release) does not affect the booster immune response, and that only antigen is required in the booster immunization (a coadjuvant in the boost does not give higher titers).     

Temporal trends and transmission patterns during the emergence of multidrug-resistant tuberculosis in New York City: a molecular epidemiologic assessment

To ascertain the role of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis transmission on multidrug-resistant (MDR) tuberculosis (TB) emergence in New York City, medical records, drug susceptibilities, and restriction fragment length polymorphisms (RFLPs) of TB cases at a city hospital between two 9-month periods (1987-1988 and 1990-1991) were reviewed. The proportion of TB patients with MDRTB increased from 10% (27/267) to 17% (38/222; P = .03). Among MDRTB patients of known HIV status, the proportion with HIV increased from 16% (3/19) to 58% (22/38; P = .006). HIV-infected MDRTB patients were more likely than the seronegative ones to have initial MDRTB (88% vs. 56%; P = .03). Among 56 MDR cases with RFLP results, 12 had unique patterns; 44 belonged to one of six clusters. During 1990-1991, 27 (75%) of 36 MDRTB patients were infected with strains isolated from HIV-seronegative patients during 1987-1988. The increase in MDRTB caused by transmission from immunocompetent to immunocompromised persons underscores the urgency of TB control in populations with increasing HIV prevalence.     

Lipid prodrugs of phosphonoacids: greatly enhanced antiviral activity of 1-O-octadecyl-sn-glycero-3-phosphonoformate in HIV-1, HSV-1 and HCMV-infected cells, in vitro

Phosphonoformate (PFA) effectively inhibits viral polymerases but is relatively ineffective in virus-infected cells in tissue culture. A lipid prodrug of phosphonoformate was synthesized by coupling the phosphonate residue of phosphonoformate to the sn-3 hydroxyl of 1-O-octadecyl-sn-glycerol. This prodrug, 1-O-octadecyl-sn-glycero-3-phosphonoformate (ODG-PFA), was 93-fold more active than phosphonoformate in cells infected with the AD169 strain of cytomegalovirus (CMV), and 111-147-fold more active in cells infected with three human clinical isolates of CMV. The compound was also 44-fold more active in human immunodeficiency virus-1 (HIV-1) infected cells and 43-fold more active in cells infected with herpes simplex virus (HSV). Studies of the mechanisms of increased antiviral activity indicate that 1-O-octadecyl-sn-glycero-3-[14C]phosphonoformate is taken up more extensively than the free drug by the host MRC-5 human lung fibroblasts. Intracellular enzymes convert 1-O-octadecyl-sn-glycero-3-phosphonoformate to phosphonoformate. This conversion does not occur in the tissue culture medium containing fetal bovine serum (FBS) or in MRC-5-conditioned medium. In view of its greatly increased in vitro potency and selectivity, 1-O-octadecyl-sn-glycero-3-phosphonoformate may be useful in treating viral diseases.     

Cytolytic activity in the genus Leishmania: involvement of a putative pore-forming protein

We describe here that parasites of the genus Leishmania contain a cytolytic activity which acts optimally at pH 5.0 to 5.5 and at 37 degrees C in vitro. or the four species examined, Leishmania (Leishmania) amazonensis and Leishmania (Leishmania) major presented considerable hemolytic activity, whereas Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis showed little and no hemolytic activity, respectively. The cytolytic factor of L. amazonensis promastigotes was characterized as a protein with no protease-, phospholipase-, or detergent-like activity, probably localized inside membranous vesicles. The use of osmotic protectants revealed the colloid-osmotic nature of hemolysis, which is indicative of pore formation in the membranes of target cells. This putative pore-forming protein also damaged nucleated cells, including macrophages, causing an increase in their membrane permeability with leakage of cytoplasmic proteins. Both promastigotes and amastigotes express this lytic activity, suggesting that the cytolysin may have a function in both stages of this parasite. The pH and temperature required for optimal activity indicate that it might be more effective within the mammalian host, particularly inside the macrophage parasitophorous vacuole. In promastigotes of L. amazonensis, the expression of lytic activity seems to be regulated during their growth in vitro, being maximal at the early stationary phase.     

Selective growth of transformed cell lines by rat liver perfusate

Perfused rat liver releases growth-promoting activity for viral, spontaneous, and chemically transformed cells. After 5 days of incubation with perfusate, cell lines 3T12-NY (a spontaneous fibroblast transformant), NQ-T1 (a chemically transformed fibroblast line), W-8 (a chemically transformed epithelial rat liver cell line increase in cell growth above controls. Their respective normal counterparts: 3T3 Cl 42, A31-714, K-16, and HEF are not so stimulated. Within another set, the virally transformed mouse fibroblast cell line, SV3T3, exhibits a 27-fold increase in growth; however, 3T3 (mouse, fibroblasts), Py3T3 (polyomatransformed 3T3 cells), SV-Fl2-101 (a flat revertant line), and SV-Py-3T3 (a doubly transformed line) are nonresponsive. Perfused rat liver also release survival activity for SV-3T3 cells. The growth-stimulating activity in liver perfusate is selective for transformed cells. It is suggested that the liver may play a role in suporting neoplasia in vivo.     

Prevention of visual anxiety and proficiency problems in the senior air transport pilot

Several actual cases were presented to show the problems encountered with flight deck vision in the middle-age presbyopic pilot both in the simulator and in flight. We have gained useful knowledge in the proper flight-deck needs and optical corrections for these pilots, which should be passed on to aviation examiners, eye specialists, and pilots themselves. This would relieve a great deal of unnecessary lost time and anxiety which results when the pilot has a correction unsuited for the cockpit and encounters extreme difficulty in simulator work and in actual flight conditions which he does not understand and which can become very frustrating and a source of anxiety because his career is at stake. This anxiety may lead to other functional ocular problems, is unnecessary, and can be prevented.