Congruent phylogeographical patterns of eight tree species in Atlantic Central Africa provide insights into the past dynamics of forest cover.

Cycles of Quaternary climatic change are assumed to be major drivers of African rainforest dynamics and evolution. However, most hypotheses on past vegetation dynamics relied on palaeobotanical records, an approach lacking spatial resolution, and on current patterns of species diversity and endemism, an approach confounding history and environmental determinism. In this context, a comparative phylogeographical study of rainforest species represents a complementary approach because Pleistocene climatic fluctuations may have left interpretable signatures in the patterns of genetic diversity within species. Using 1274 plastid DNA sequences from eight tree species (Afrostyrax kamerunensis, A. lepidophyllus, Erythrophleum suaveolens, Greenwayodendron suaveolens, Milicia excelsa, Santiria trimera, Scorodophloeus zenkeri and Symphonia globulifera) sampled in 50 populations of Atlantic Central Africa (ACA), we averaged divergence across species to produce the first map of the region synthesizing genetic distinctiveness and standardized divergence within and among localities. Significant congruence in divergence was detected mostly among five of the eight species and was stronger in the northern ACA. This pattern is compatible with a scenario of past forest fragmentation and recolonization whereby forests from eastern Cameroon and northeastern Gabon would have been more affected by past climatic change than those of western Cameroon (where one or more refugia would have occurred). By contrast, southern ACA (Gabon) displayed low congruence among species that may reflect less drastic past forest fragmentation or a more complex history of vegetation changes. Finally, we also highlight the potential impact of current environmental barriers on spatial genetic structures.

[Evaluation of the protocol CMA reinforced in the treatment of endemic Burkitt lymphoma at CHU of Yopougon in Abidjan]. / Evaluation du protocole CMA renforcé dans le traitement du lymphome de Burkitt endémique au CHU de Yopougon à Abidjan.

We report the results of the protocol CMA (cyclophosphamide, methotrexate, Aracytine) reinforced of 26 patients affected by Burkitt lymphoma in facial-maxillary localisation, in a retrospective study from January 2000 till December 2007 and prospective from January till September 2008. Their average age was 7.89 years, with a sex ratio of 2.71. The global response to the treatment was 92.3% with 57.7% of complete remission and 34.6% of incomplete remission. The morbidity related to treatment was essentially a haematological complication (84.6%) and hydroelectrolytic complication (84.6%). Evolution was made towards death in 30.8 and 15.4% were lost of view. The median monitoring was 18.2 months. Treatment response was linked to the therapeutic compliance (P < 0.001), and the delay of consultation (P = 0.01).