Expression of gag precursor protein and secretion of virus-like gag particles of HIV-2 from recombinant baculovirus-infected insect cells

A recombinant baculovirus carrying the gag gene but lacking the protease coding sequences of human immunodeficiency virus type 2 (HIV-2) has been constructed. When this recombinant baculovirus is used to infect insect cells, a high level of gag precursor protein, gag pr41, is expressed. Electron microscopy showed that the majority of gag pr41 was budding through the plasma membrane and being released into the culture medium in spherical virus-like particles with a diameter of approximately 100 nm. Metabolic labeling demonstrates that gag pr41 is myristylated. Our results demonstrated that HIV-2 gag pr41 can be assembled into virus-like particles in the absence of other HIV proteins. Rabbits immunized with purified gag pr41 particles produced high-titer antibody and Western blot analysis showed that anti-gag pr41 rabbit sera recognize p17, p24, and p55 gag proteins of HIV-1. These results show that gag pr41 particles are highly immunogenic and that gag proteins of HIV-1 and HIV-2 have similar antigenic epitopes.

[Effect of capsaicin on the release of substance P from spinal cord and blood pressure]

The role of substance P (SP) in the regulation of sympathetic outflow to the cardiovascular system was assessed. Intrathecal injection(ith) of capsaicin caused a release of SP from the spinal cord and resulted in an increase in blood pressure and heart rate accompanied by an elevation of plasma adrenaline and noradrenaline. This pressor response was blocked by ith SP antagonist D-Pro2, D-Phe7, D-Trp9-SP or antiserum against SP. The immunohistochemical study showed that the SP-like immunoreactivity in T-8 of the spinal cord was decreased as the amount of capsaicin administrated was increased. Spinal cord transection had no effect on pressor responses caused by ith 10 micrograms capsaicin. These results suggest that SP transmits excitatory information to the cardiovascular system via spinal sympathetic pathway.

Vasectomy and health: cardiovascular and other diseases following vasectomy in Sichuan province, People's Republic of China

The long-term sequelae of vasectomy were studied in a retrospective cohort study of 4596 vasectomized and 4340 nonvasectomized farmers from eight rural communes in Sichuan, People's Republic of China. The mean duration since the operation was 14.5 years with a range of 10 to 25 years. At the time of evaluation the vasectomized men were generally healthier than the non-vasectomized for a wide range of health indicators including clinical signs of cardiovascular disease, resting ECG changes, positive ECG changes following a maximal stress test, or fundus abnormalities. The lack of association between vasectomy and cardiovascular disease noted in Europe and the USA is supported by the present study conducted in a population with a low prevalence of cardiovascular disease and risk factors.