Emerging Patterns of HIV Infection and Control in the Philippines

A total of 50 carriers of the human immunodeficiency virus (HIV), 46 of them female prostitutes, have been detected through seroprevalence surveys by the Department of Health, Manila. Infection rates are highest in two small cities near foreign military bases and in the tourist district of MetroManila. Nine patients with the acquired immunodeficiency syndrome (AIDS) who contracted the disease outside the country have been reported, with opportunistic infections being the major clinical feature. Public information measures heavily utilize the mass media, and there is anecdotal evidence that awareness of the disease among the urban population is increasing. The National AIDS Committee foresees that a large proportion of the cases seen in the Philippines over the next few years will be returning nationals who were infected abroad.     

Variation of lumbar spine stiffness with load

Mechanical studies of the Functional Spinal Unit (FSU) in-vitro have shown that the slopes of the load-displacement curves increase with load. This nonlinearity implies that the stiffness of the FSU is not constant over the range of physiologic loads, and that measurements obtained for FSU specimens through the application of individual loads cannot be summed to predict the response of the specimens to combined loads. Both experimental and analytical methods were developed in the present study to better quantify the nonlinear FSU load-displacement response and to calculate the coupled stiffness of FSU specimens at combined states of load reflecting in-vivo conditions. Results referenced to the center of the vertebral body indicate that lumbar FSU specimens are stiffer in flexion than in extension, and that FSU specimens loaded in flexion are stiffer at high loads than at low loads. The importance of combined load testing and a nonlinear interpretation of load-displacement data is demonstrated.     

Direct and Continuous Detection of ATP Secretion from Primary Monolayer Cultures of Bovine Adrenal Chromaffin Cells

A method was developed for direct and continuous detection of secretion of ATP from primary monolayer cultures of bovine adrenal chromaffin cells. ATP, which is costored with catecholamines within adrenal chromaffin cells, was released into the incubation medium, where it reacted with firefly luciferin-luciferase producing light detected by a photomultiplier located directly below the culture well. Acetylcholine, nicotine, the Ca2+ ionophore A23187, BaCl2, and KCl induced release of ATP. Induction of release of ATP by acetylcholine was dose dependent, with a threshold at 10(-7) M and a maximum at 10(-4) M. The dose-response curve for nicotine was bell shaped, with a threshold at 10(-7) M, a maximum at 10(-5) M, and diminished release at higher concentrations, an observation indicative of desensitization. Investigation of the initial rates of ATP secretion revealed that 10(-4) M nicotine actually induced release of ATP at a faster rate than 10(-5) M nicotine. However, the rate of ATP release evoked by 10(-4) M nicotine began to decline by 6 s, a result indicating the onset of receptor desensitization, whereas release induced by 10(-5) M nicotine continued unabated. Induction of release of ATP by acetylcholine or nicotine was biphasic, with a rapid, initial phase of release followed by a plateau at 0.5-1.5 min and a second phase of release beginning at 1.5-2 min, reaching a maximum by 2-3 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Horizontal transmission of murine retroviruses.

Both a feral mouse ecotropic virus (WM-E) and Friend ecotropic virus (F-MuLV) were transmitted horizontally among adult mice. Infection resulted in the production of antiviral antibody in the recipients, with no evidence of viremia or clinical disease. However, persistent low-level virus replication was detectable in the spleens of these mice as long as 8 months after initial infection. External secretions, including saliva, semen, and uterine secretions from viremic mice contained high concentrations of infectious virus. Nevertheless, transmission occurred only from viremic males to either males or females. Male-to-male transmission appeared to occur by parenteral inoculation of infectious saliva during fighting behavior. Evidence is presented that infection of females was by the venereal route. Of four mouse strains examined, NFS/N, IRW, and C57L females were all susceptible to venereal infection, whereas AKR mice were not. Since AKR mice are susceptible to infection by WM-E administered parenterally, this resistance appeared to be mediated by local viral interference due to the high-level expression of endogenous Akv gp70 within the female reproductive tract. Although both WM-E and F-MuLV were transmitted from viremic males to females, infection by WM-E was significantly more efficient than that by F-MuLV. This difference correlated with a distinct difference in cellular tropism of WM-E and F-MuLV within the epididymis of viremic males. F-MuLV gp70 was expressed only within stromal elements, whereas WM-E gp70 was seen largely within the epithelial lining cells and luminal contents of the duct. No evidence of virus expression within germ cells was observed. The possible influence of virus expression by epithelial cells of the female reproductive tract on infection of embryos is discussed.     

Gender differences in eicosanoid production from macrophages of arthritis-susceptible mice

Collagen-induced arthritis (CIA) in rodents is an experimental animal model that shares many clinical and pathologic findings with rheumatoid arthritis in man. Our previous findings suggested that the amelioration of CIA in mice by a fish oil diet was associated with macrophage accumulation and metabolism of eicosapentaenoic acid and a subsequently altered prostaglandin (PG) profile. In these experiments, we examined the role of gender and found that macrophages from female arthritis-susceptible B10.RIII or B10.G mice synthesized more PG and thromboxane than macrophages isolated from the males. Compared with males, female mice had higher circulating anti-type II collagen antibodies but were less likely to develop CIA. Females, especially those on a fish oil diet, developed a much less severe disease than the males. This supports our hypothesis that the type and/or amount of eicosanoid produced from the macrophage may alter the course of experimentally induced arthritis.     

A fish oil diet inhibits amyloid P component (AP) acute phase responses in arthritis susceptible mice

Amyloid P component (AP) bears close homology with C-reactive protein and behaves as an acute phase reactant in the plasma of mice but not in man. Our aim was to determine whether AP is influenced by diet, gender, and arthritis severity in a murine model of arthritis. B10.RIII mice were segregated according to gender and diet at 8 wk of age: the source of fat was either corn oil, fish oil, or beef tallow (5% by weight). Four weeks later, each mouse was immunized with 100 micrograms fetal bovine type II collagen, and the incidence and severity of arthritis was noted at weekly intervals. AP was measured by competitive ELISA in plasma taken 5 wk and 15 wk after immunization. AP levels were less in fish oil fed males and females. Under all conditions tested AP levels of females were greater than in males. There was a negative correlation between AP levels and the severity of arthritis. We conclude from these data that although AP levels cannot be used as indices of arthritis severity, there are significant dietary and gender effects on AP concentrations as long as 15 wk after immunization with type II collagen.     

Behavioral changes of a juvenile gorilla after a transfer to a more naturalistic environment

Play behavior and stress-associated behavior of a captive juvenile gorilla were observed before and after his transfer to a larger and more natural environment. The gorilla was observed for 4 months after the transfer and at 1 and 4 years after the transfer. Throughout his first month in the new environment play decreased dramatically. Although play subsequently increased again 2 months and 1 year after the transfer, it never reached the levels of play in the old environment. Four years after the move his play had decreased again to the low level of his first month in the new environment. Two of his stress-associated behaviors, coprophagy and regurgitation/reingestion, decreased after the transfer. Self-clasping behavior increased initially in the new environment and remained at high levels 1 year after the move. Four years after the move his self-clasping behavior was significantly less than at 1 year after the move; however, it continued to be significantly greater than in the old environment. These findings suggest that larger and more natural environments do not necessarily result in more play activity or a reduction in all stress-associated behavior.     

bcd: A mutation affecting the width of organelle domains in the cortex of Tetrahymena thermophila

Summary A single-gene recessive mutation, bcd (broadened cortical domains), of Tetrahymena thermophila is characterized by a variable broadening of the spatial domains within which cortical organelles, including both the contractile vacuole pores (CVP) and oral apparatus (OA), are formed. The phenotype is not temperature-sensitive. During the development of the organelles of the mutant prior to cell division, extra CVPs and extra oral primordia (OP) appear near ciliary rows adjacent to the rows at which these structures normally form. In the later stages of development, some, but not all, of these extra structures are resorbed, or in the case of the oral domain, multiple adjacent OPs may be completely or partially integrated into a single enlarged OA. When multiple OAs persist, one or more of these may display a reversed orientation reminiscent of those encountered in janus mutants. However, unlike janus, bcd cells do not express any sign of a mirror-image global organization.Our results can best be accounted for by postulating that the bcd mutation affects some common determinant of the widths of both CVP and OA domains. Studies are in progress which explore the relationship between this width-determining mechanism(s) and the mechanism(s) determining the location of cortical organelles around the cell circumference.