Evaluation de la chimiorésistance à la sulfadoxine-pyrimethamine et des mutations des gènes dihydrofolate réductase et dihydropteroate synthétase dans le district de santé de Ndu au nord-ouest, Cameroun

Les données cliniques sur la résistance au sulfadoxine-pyriméthamine(SP) sont peu précises dans plusieurs localités du Cameroun. En plus, très peu d’informations sont disponibles sur la corrélation entre les marqueurs moléculaires, la résistance et l’échec du traitement avec SP. Dans l’optique de mieux appréhender cette situation, nous avons entrepris d’évaluer l’efficacité du sulfadoxine-pyriméthamine (SP), ainsi que le potentiel des marqueurs moléculaires dans le suivi de la résistance dans trois sites du district de santé de Ndu. 296 patients de tout âge infectés par la forme non compliquée de Plasmodium falciparum ont été soumis à un traitement au SP pendant la période d’avril 2001 à novembre 2004, et les résultats évalués. Une évaluation des mutations des gènes de dihydrofolate réductase (dhfr) et  dihydroptéroate synthétase (dhps) du P. falciparum dans le sang de 100 patients d’âges inférieurs ou égaux à 10 ans a été effectuée le jour de leur admission en clinique. Les résultats obtenus indiquent 51,28% de patients qui donnent des réponses cliniques et parasitologiques adéquates, 33,33% d’échec thérapeutique précoce, 4,49% d’échec thérapeutique tardif, et 9,89% d’échec parasitologique tardif. Les mutations de la Gly437 ont été retrouvées dans 37% des échantillons. L’indice génotypique de resistance calculé suivant ce marqueur était de 0,76. Les mutations liées à la Asn108 ont été retrouvées dans 87% des échantillons, avec un indice génotypique de résistance de 1,79. En conclusion, il découle de nos résultats cliniques et moléculaires que la thérapie SP aurait un effet thérapeutique de courte durée dans le district de santé de Ndu. D’autre part, les génotypes mutants dhfr et dhps seraient des facteurs potentiels d’alerte précoce dans l’augmentation de la résistance au SP.Mots clés: Plasmodium falciparum, dhps, dhfr, marqueurs moléculaires, S

Synthesis, stereochemistry and antimicrobial activity of copper(II) and nickel(II) complexes of 4-phenylsemicarbazones

2-Acetylpyridine-(4-phenylsemicarbazone) and o-vanillin-(4-phenylsemicarbazone) have been prepared and characterized on the basis of elemental analyses, infrared, electronic, 1H and 13C NMR spectra. Several nickel(II) and copper(II) complexes have been obtained from these ligands. The IR spectra of the ligands as well as those of their complexes suggest that 2-acetylpyridine-(4-phenylsemicarbazone) is a neutral tridentate molecule while o-vanillin-(4-phenylsemicarbazone) is a monobasic tridentate molecule. On the basis of the analytical data, magnetic moments and spectral data, a square-planar geometry has been proposed for the nickel(II) and copper(II) complexes with these ligands. Some representative complexes of copper(II) and nickel(II) were found to have remarkable antifungal and antibacterial activity.KEY WORDS: 4-Phenylsemicarbazone, Metal complexes, Stereochemistry, Antimicrobial activity Bull. Chem. Soc. Ethiop. 2011, 25(3), 361-370

Synthesis, crystal structure and magnetic properties of [Cu(mal)(abpt)(H2O)].3/2H2O and [Cu2(sq)(abpt) 2].2H2O (mal = malonate, sq = squarate, abpt =4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole)

Two new mixed-ligand complexes of formula [Cu(mal)(abpt)(H2O)].3/2H2O (1) and [Cu2(sq)(abpt) 2].2H2O (2) [mal = malonate, abpt = 4-amino-3,5-di-2-pyridyl-4H-1,2,4 triazole and sq = squarate], have been prepared and characterized by X-ray crystal structure determination and magnetic studies. Complex 1 crystallizes in the monoclinic system, space group C2/c, with a = 14.0086(2) Å, b = 10.0980(2) Å, c = 25.630(4) Å; β = 97.5900(10) o, and Z = 8. Complex 2 crystallizes in the triclinic system, space group P-1 with a = 7.5696(15) Å, b = 8.4697(17) Å, c = 11.049(2) Å; β = 93.00(3)o,  α = 96.98(3), γ = 90.111(3) and Z = 1. Complex 1 consist of a neutral mononuclear [Cu(mal)(abpt)(H2O)] unit and water molecule of crystallization in a distorted square pyramidal coordination sphere, while complex 2 is viewed as being made up of [Cu(sq)(abpt)2] units with the squarato ligand bridging the two copper(II) cations. Variable temperature magnetic behaviour of the complexes reveals the existence of weak antiferromagnetic interaction for complex 1 and weak ferromagnetic intrachain interaction for complex 2.KEY WORDS: Copper(II) complexes, Mixed-ligand, Magnetic properties, Malonate, Squarate, 4-Amino-3,5-di-2-pyridyl-4H-1,2,4 triazoleBull. Chem. Soc. Ethiop. 2011, 25(1), 53-60

Synthesis, crystal and molecular structure of manganese (II) complex of 2-acetylpyridine N (4) ethylthiosemicarbazone

A novel Mn(II) complex with thiosemicarbazone derived from 2-acetylpyridine and N(4)-ethylthiosemicarbazide has been prepared. The single-crystal X-ray analysis of the Mn(II) complex showed a distorted octahedral MnN4S2 environment with the ligand chelating via the nitrogen and sulfur donor atoms in a tridentate manner. The triclinic form of the ligand which has crystallized in a monoclinic system in other works is also described. The basicity of  nitrogen atoms of the ligand was tested with its reaction with HNO3 and the structure of the salt obtained is reported. The result shows that the lone pair of the pyridine nitrogen is more available due to the delocalization of other nitrogen lone pair of electron. http://dx.doi.org/10.21060/cis.2016.41

Dementia and cognitive impairment in French-speaking Sub-Saharan Africa: a comprehensive review on moving out of the shadows of neglect

Dementia is a global public health problem with increasing prevalence and incidence worldwide. The African continent is expected to bear the biggest brunt of the burden of dementia by 2050 because of the rapid demographic changes, including rapid population growth, an increase in life expectancy, and ageing. However, French-speaking Sub-Saharan African (FS-SSA) countries are underrepresented in research on dementia in Africa. While the reasons are diverse and complex, linguistic and cultural barriers to research, disproportionately affect these countries and may be significant factors. Any efforts, therefore, to redress the burden of dementia in Africa must consider the specific demographic, cultural, and linguistic characteristics of FS-SSA countries. This scoping review explores the current state of knowledge in dementia and cognitive impairment in Sub-Saharan Africa, highlighting research gaps and specific patterns unique to FS-SSA Africa. We identify pathways for research to bridge the knowledge gaps on dementia in FS-SSA as part of the global endeavor to tackle dementia worldwide

Dementia Prevalence and Onchocerca volvulus Infection among Rural Elderly Persons in the Ntui Health District, Cameroon: A Population-Based Study

Recent research suggests that infection with Onchocerca volvulus induces neurocognitive decline. This study sought to compare the cognitive outcomes of elderly persons based on onchocerciasis infection status and report the overall prevalence of dementia in the rural Ntui Health District in Cameroon. A community-based approach was used to recruit 103 participants aged ≥60 years. Dementia screening was done using the Community Screening Interview for Dementia (CSID) tool with a cut-off value of ≤29.5. O. volvulus infection was determined via microscopic examination of skin snips and serological testing of Ov16 antibodies using rapid diagnostic tests. Overall, the prevalence of dementia was 10.7%. Among the tested individuals, 17.9% (15/84) and 62.1% (41/66) were positive for O. volvulus and Ov16 antibodies, respectively. A multivariable linear regression model of CSID scores found a significant positive association with education level (8.654; 95% CI: 2.0870 to 15.222). However, having a positive skin snip for O. volvulus (−3.399; 95% CI: −6.805 to 0.007) and inhaling tobacco (−5.441; 95% CI: −9.137 to −1.744) tended to lower the CSID scores. Ongoing onchocerciasis transmission in the Ntui Health District may constitute a risk factor for dementia. Strengthening onchocerciasis elimination and adopting healthier lifestyles would contribute to dementia prevention among the elderly residing in endemic communities

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Antimicrobial Activities Of Synthesized Zinc(II) Mixed-Ligand Complexes Derived From 2- Acetylpyridine-4-Phenylsemicarbazone And Nitrogen-Sulphurmonodentate Ligands

Abstract: The reaction of zinc chloride with 2-acetylpyridine-4-phenylsemicarbazone and nitrogen-sulphurmonodentate ligands such as thiophene, pyridine, picoline ,aniline and ammonia; yielded five novel mixed -ligand complexes: Zn(2-Ac.4-Psc.Th)Cl2 ,Zn(2-Ac.4-Psc.Py)Cl2, Zn(2-Ac.4-Psc.Pi)Cl2, Zn(2Ac.4-Psc.An)Cl2 and Zn(2-Ac.Psc.Am)Cl2. These were characterized by elemental analysis,molar conductivity, 1 H and 13 C-NMR, IR and electronic absorption spectroscopic studies.All the complexes possess tetrahedral geometries. The antimicrobial activities were evaluated against staphylococcus aureus, Bacillus anthracis,Aspergillusnigers andCandida albicans.The result of significant inhibition of growth and proliferation of these microbes by the chelates were obtained particularly with the highest efficiency shown by thethiophene and aniline incorporated complexe