Transmission of cutaneous leishmaniasis by sand flies is enhanced by regurgitation of fPPG

Sand flies are the exclusive vectors of the protozoan parasite Leishmania, but the mechanism of transmission by fly bite has not been determined nor incorporated into experimental models of infection. In sand flies with mature Leishmania infections the anterior midgut is blocked by a gel of parasite origin, the promastigote secretory gel. Here we analyse the inocula from Leishmania mexicana-infected Lutzomyia longipalpis sand flies. Analysis revealed the size of the infectious dose, the underlying mechanism of parasite delivery by regurgitation, and the novel contribution made to infection by filamentous proteophosphoglycan (fPPG), a component of promastigote secretory gel found to accompany the parasites during transmission. Collectively these results have important implications for understanding the relationship between the parasite and its vector, the pathology of cutaneous leishmaniasis in humans and also the development of effective vaccines and drugs. These findings emphasize that to fully understand transmission of vector-borne diseases the interaction between the parasite, its vector and the mammalian host must be considered together.     

Vitamin D and reproduction in Wistar rats]

Females have received from weaning a semi-synthetic diet (0,35% Ca; 0,32% P; 0,03% Mg), with or without vitamin D (+/- D). Fertility of these females was not changed. At weaning, the young from mothers--D had lower weight, calcemia and phosphatemia, but the ash content of the femur was the same as for young from mothers + D. Young rats from mothers +/- D were given the diet with or without vitamin D. 19 days after weaning, the diet of the mother (+/- D) appears to be the principal factor for growth, calcemia and the ash content of the femur; the diet of the young (+/- D) produced only slight differences between ash contents.     

Antibody-dependent adherence of peritoneal cells of the rat to Trichinella spiralis larvae]

Washed peritoneal exudate cells from normal Rats firmly adhere to Trichinella spiralis larvae in the presence of serum containing anti-Trichinella antibodies. This effect is observed when muscle larvae, cells and dilutions of anti-sera are incubated for 1 hr. at 37 degrees C. No adherence takes place at 4 degrees C. Whole serum or its gammaglobulin fraction are active and effect is inhibited by the addition of Trichinella antigens. Complement is not essential since antiserum heated for 2 hrs. at 56 degrees C is active. Washed cells from infested animals do not adhere to the larvae in the absence of antiserum.     

DNA-polyintercalation compounds. Synthesis of ellipticine dimers]

Many symmetrical bis [9-methoxy 2-ellipticinium] dioxodiazaalkanes salts were synthesized from 9-methoxy ellipticine. An analog derivative of 9-hydroxy ellipticine was also prepared. Some of these dimers bind to DNA by a bifunctionnal mode of intercalation.     

Variation of the inflammatory response of an autologus implant function and viability: mixed and unilateral inflammatory response]

The behaviour of an autologous grafted implant depends upon its viability. In our study, pericardial implants were used as cardiac valves. Results showed that when using fresh live pericardium, an inflammatory response developed destroying it within 8 days. When implants cells were killed without alteration of their antigenicity--in order to prevent rejection--cellular growth and neovascularisation from implantation site occurred leading to a secondary live graft. Controlled killing of the implant seems to be an essential step in order to get live grafts.