In vitro cultivation of fields isolates of Plasmodium falciparum in Mali

Malaria immunology, molecular biology and pathogenicity studies often require the adaptation of Plasmodium falciparum field isolates to continuous in vitro cultivation. For this purpose we have established propagation protocols of asexual erythrocytic stages of P. falciparum samples from malaria patients or asymptomatic carriers in Mali. The parasites were grown in standard culture medium supplemented by human serum and in a culture medium without human serum but supplemented by AlbuMax 1. The candle jar environment and tissue culture flasks gassed with 5% CO2, 5% O2 and 90% N2 obtained from a portable gas mixer were used. Protocols for parasite cultivation in a resource-poor setting were developed. These protocols were successfully applied to fresh isolates in Mali as well as to blood samples frozen in liquid nitrogen and shipped to a laboratory in U.S.A.     

Molecular diagnosis of resistance to antimalarial drugs during epidemics and in war zones

Plasmodium falciparum mutations pfcrt K76T and the dhfr/dhps "quintuple mutant" are molecular markers of resistance to chloroquine and sulfadoxine-pyrimethamine, respectively. During an epidemic of P. falciparum malaria in an area of political unrest in northern Mali, where standard efficacy studies have been impossible, we measured the prevalence of these markers in a cross-sectional survey. In 80% of cases of infection, pfcrt K76T was detected, but none of the cases carried the dhfr/dhps quintuple mutant. On the basis of these results, chloroquine was replaced by sulfadoxine-pyrimethamine in control efforts. This example illustrates how molecular markers for drug resistance can provide timely data that inform malaria-control policy during epidemics and other emergency situations.     

Toxicity and genotoxicity of antimalarial alkaloid rich extracts derived from Mitragyna inermis O. Kuntze and Nauclea latifolia

The toxicity and the genotoxicity of antimalarial alkaloid rich extracts derived from two plants used in traditional medicine in Mali (Mitragyna inermis (Willd.) O. Kuntze Rubiaceae and Nauclea latifolia (Sm.) Rubiaceae) were evaluated on in vitro and in vivo systems. The results demonstrated that an alkaloid rich extract derived from M. inermis induced a strong inhibition of protein synthesis in mammalian cells but did not exhibit mutagenic or genotoxic activity. An alkaloid rich extract derived from N. latifolia could interact in vitro with DNA of bacteria and mammalian cells, leading to G2-M cell cycle arrest and heritable DNA-damage, as well as inducing in vivo single-strand breaks in liver, kidney and blood cells.     

Epidemiology of malaria in a village of Sudanese savannah area in Mali (Bancoumana). 2. Entomo-parasitological and clinical study

We carried out five cross sectional surveys between 1993 and 1994 to assess the epidemiology of malaria in the village of Bancoumana, located in the Sudanese savannah areas of Mali. Each survey included a collection of entomological, clinical, parasitological and immunological data. The study population involved 1600 children from six months to 9 years of age. The main vector was Anopheles gambiae s.l., man bite rate and entomological inoculation rate were maximum respectively in August (peak of the transmission season) and October (end of transmission season). Plasmodium. falciparum was the main parasite species observed. Spleen enlargement rate, parasite rate, gametocyte rate and parasite density varied significantly with age and season. The parasite rate, gametocyte rate and parasite density were significantly low in October 1994 compared with October 1993 while the entomologic parameter did not show any variation over the two years. This reduction of parasitologic index between 1993 and 1994 may be related to an increase of anti-malarial drug use in the population. Our results show that malaria is hyperendemic in the village of Bancoumana.     

Prevalence and perception of schistosomiasis in a periurban school of Bamako in Mali

The prevalence of urinary and intestinal schistosomiasis, the knowledge, attitude and practice (KAP) regarding the disease among both the children and their parents were investigated in Djikoroni para, a Suburban area of Bamako. The prevalence of Schistosoma haematobium and S. mansoni were respectively 69.8% and 8.7%. Compared with the girls, the boys were significantly more infected by S. haematobium (p = 5.10(-3)), but no difference between the sexes was observed for S. mansoni (p = 0.36). Interviews indicated that 88% of children and 91% of adults considered micro-haematuria as a pathology, but did not know anything about intestinal schistosomiasis. The low sensitivity of micro-haematuria (56.8%) and of the criterion "abdominal pains" (66.7%) indicated that they couldn't be relevant diagnosis signs. The symptoms and mode of transmission were generally well understood for S. haematobium but not for S. mansoni. The later parasite, its intermediate host and their interactions were unknown. The main man water contacts are bathing and playing in the Woyowayanko and in the Niger river. Inadequate perception of schistosomiasis contributes to maintain schistosomiasis at a high level of prevalence in Djikoroni.     

Biological evaluation of glass ionomer cements

Summary. Sixty human premolar and canine teeth were used in this study. Class V cavities were prepared with a turbine handpiece. The experimental material was ASPA, with silicate cement and zinc oxide-eugenol cements being used as controls. The teeth were extracted approximately 4 days, 30 days or 90 days after insertion of the filling material. They were demineralized and prepared for histological examination. The test procedure and evaluation closely followed recommendations by the FDI (1980). The reaction at the short time interval for each material was similar, while at the intermediate and long periods silicate cement caused the most inflammation, zinc oxideeugenol cement the least, and ASPA an intermediate response. The reaction to ASPA was reduced at the long period compared with the intermediate period.     

Presence of Leishmania major MON-26 in Mali

The arabo-african zymodem MON-26 was identified for the first time in an autochtonous patient from Mali. L. major has been previously identified in this country but it was in European patient and it was zymodem MON-25.     

Morphogenesis and Regulation of Bergmann Glial Processes During Purkinje Cell Dendritic Spine Ensheathment and Synaptogenesis

星形胶质细胞在突触形成中发挥重要作用,但星形胶质细胞突起如何在发育过程中与突触结构相联系还不是很清楚。本文分析在小脑突触发生过程中Bergmann胶质细胞(BG)突起生长的类型。本文发现在这个过程中,BG突起向外生长与树突棘增多的包被作用相关。此外,双光子时间分辩显像显示BG突起是高度动态的,在棘包被过程中突起趋于稳定。虽然突触活力依赖于肌动蛋白的聚合作用,但细胞骨架调节器Rac1和RhoG的活动在胶质细胞突起的动力或密度上并未发挥作用,而是对于保持突起长度起关键性作用。本文扩展这个发现,探查突起形态和包被之间的关系,发现缩短的突起导致棘覆盖的减少。本文进一步发现在BG表达dn-Rac1和低水平突触包被的区域,显示突触数量的增加。这些分析提示BG突起如何生长并包围突触结构,阐明BG突起结构对突触包被适当发育的重要性,并提示包被在突触形成中的作用。