Bancroftian filariasis in Pondicherry, south India--epidemiological impact of recovery of the vector population.

An Integrated Vector Management (IVM) strategy was implemented from 1981 to 1985 in one part of Pondicherry, South India, for the control of the bancroftian filariasis vector Culex quinquefasciatus (the IVM area). The rest of the town (the comparison area) received the conventional larvicidal input. After 1985 both the areas were managed conventionally. The switch to conventional strategy resulted in an increase of vector density in both areas. The microfilaraemia prevalence in humans showed a general decline (P less than 0.05) from 1986 to 1989 only in the IVM area whereas its intensity did not change significantly in either area. While the age-specific rate of gain of infection was generally unchanged in the IVM area, an increase in all age classes was observed after 1985 in the comparison area, where the Annual Transmission Index was high during the previous years. In both areas the rate of loss of infection increased during 1986-9 compared to 1981-6. The results suggest that 3 years is too short a period to relate the changes in entomological parameters to those in the microfilaraemia status of the population.     

A study of galactose intolerance in human and rat liver in vivo by 31P magnetic resonance spectroscopy.

An oral load of 20 mg/kg galactose produces significant changes in the 31P magnetic resonance spectrum of the liver of a galactosemic patient. The peak at 5.2 ppm (which includes inorganic phosphate and galactose-1-phosphate) increased on two occasions to about twice its original size 60 min after galactose administration. An oral load of 10 mg/kg galactose given to a second patient produced no discernible changes at 30 min. We have also used an animal model of galactose intolerance, in which galactose metabolism in rats was blocked by the acute administration of ethanol. Studies in vivo and in vitro showed that the increase in the peak at 5.2 ppm was largely due to galactose-1-phosphate. We have shown in this preliminary study that small amounts of galactose can produce significant elevation of hepatic galactose-1-phosphate, which can be detected by 31P magnetic resonance spectroscopy.     

Direct activation of human monocyte-derived macrophages by a bacterial glycoprotein extract inhibits the intracellular multiplication of virulent Legionella pneumophila serogroup 1.

Intracellular multiplication of virulent Legionella pneumophila serogroup 1 was inhibited by human monocyte-derived macrophages activated by a glycoprotein extract of Klebsiella pneumoniae, RU 41.740. Macrophage cultures were infected with L. pneumophila in the presence of immune antibodies on day 7 of culture. Extracellular bacteria were removed an hour after infection, and various concentrations of RU 41.740 or an antibiotic, erythromycin, were added. Intracellular multiplication in the presence of RU 41.740 was significantly slowed down compared with that of cultures without RU 41.740. The reduction was, however, significantly less than that effected by erythromycin, which was used as a positive control for inhibition of intracellular multiplication. Cultures incubated with RU 41.740 before infection also demonstrated a significant reduction in the intracellular multiplication of L. pneumophila. In addition, RU 41.740 increased superoxide anion production from human monocytes in suspension in the presence of L. pneumophila. These results show that direct nonspecific activation of macrophages by a bacterial glycoprotein inhibits the intracellular multiplication of L. pneumophila and may suggest a role for activated macrophages in host defense against intracellular pathogens.