In vitro susceptibility to quinine and microsatellite variations of the Plasmodium falciparum Na+/H+ exchanger (Pfnhe-1) gene: the absence of association in clinical isolates from the Republic of Congo

<p>Abstract</p> <p>Background</p> <p>Quinine is still recommended as an effective therapy for severe cases of <it>Plasmodium falciparum </it>malaria, but the parasite has developed resistance to the drug in some cases. Investigations into the genetic basis for quinine resistance (QNR) suggest that QNR is complex and involves several genes, with either an additive or a pairwise effect. The results obtained when assessing one of these genes, the plasmodial Na⁺/H⁺exchanger, <it>Pfnhe-1</it>, were found to depend upon the geographic origin of the parasite strain. Most of the associations identified have been made in Asian strains; in contrast, in African strains, the influence of <it>Pfnhe </it>on QNR is not apparent. However, a recent study carried out in Kenya did show a significant association between a <it>Pfnhe </it>polymorphism and QNR. As genetic differences may exist across the African continent, more field data are needed to determine if this association exists in other African regions. In the present study, association between <it>Pfnhe </it>and QNR is investigated in a series of isolates from central Africa.</p> <p>Methods</p> <p>The sequence analysis of the polymorphisms at the <it>Pfnhe-1 </it>ms4760 microsatellite and the evaluation of <it>in vitro </it>quinine susceptibility (by isotopic assay) were conducted in 74 <it>P. falciparum </it>isolates from the Republic of Congo.</p> <p>Results</p> <p>Polymorphisms in the number of DNNND or NHNDNHNNDDD repeats in the <it>Pfnhe-1 </it>ms4760 microsatellite were not associated with quinine susceptibility.</p> <p>Conclusions</p> <p>The polymorphism in the microsatellite ms4760 in <it>Pfnhe-1 </it>that cannot be used to monitor quinine response in the regions of the Republic of Congo, where the isolates came from. This finding suggests that there exists a genetic background associated with geographic area for the association that will prevent the use of <it>Pfnhe </it>as a molecular marker for QNR. The contribution of <it>Pfnhe </it>to the <it>in vitro </it>response to quinine remains to be assessed in other regions, including in countries with different levels of drug pressure.</p

Intestinal strongyloidiasis and hyperinfection syndrome

In spite of recent advances with experiments on animal models, strongyloidiasis, an infection caused by the nematode parasite Strongyloides stercoralis, has still been an elusive disease. Though endemic in some developing countries, strongyloidiasis still poses a threat to the developed world. Due to the peculiar but characteristic features of autoinfection, hyperinfection syndrome involving only pulmonary and gastrointestinal systems, and disseminated infection with involvement of other organs, strongyloidiasis needs special attention by the physician, especially one serving patients in areas endemic for strongyloidiasis. Strongyloidiasis can occur without any symptoms, or as a potentially fatal hyperinfection or disseminated infection. Th(2 )cell-mediated immunity, humoral immunity and mucosal immunity have been shown to have protective effects against this parasitic infection especially in animal models. Any factors that suppress these mechanisms (such as intercurrent immune suppression or glucocorticoid therapy) could potentially trigger hyperinfection or disseminated infection which could be fatal. Even with the recent advances in laboratory tests, strongyloidiasis is still difficult to diagnose. But once diagnosed, the disease can be treated effectively with antihelminthic drugs like Ivermectin. This review article summarizes a case of strongyloidiasis and various aspects of strongyloidiasis, with emphasis on epidemiology, life cycle of Strongyloides stercoralis, clinical manifestations of the disease, corticosteroids and strongyloidiasis, diagnostic aspects of the disease, various host defense pathways against strongyloidiasis, and available treatment options

Printemps pour un J 3...

Contient une table des matièresAvec mode text