Contribution of ESR dosimetry for irradiation of geological and archaeological samples with a Co panoramic source

A very precise dosimetry of a field of artificial irradiation is essential to estimate an accurate ESR Equivalent Dose (ED) in archaeology and geology. Archaeological powder samples and one sample of DL-alanine powder as control were prepared by IPH. Some alanine dosimeters of LMRI, constituted of L-alanine pellets, were joined to the IPH samples and together, irradiated in boxes using panoramic ⁶⁰Co source under different experimental conditions. The LMRI had in charge the control of the process of irradiation and the measurement of each absorbed dose and dose rate delivered to the different series of boxes. This study consists in the evaluation of the distribution of dose on the samples. The ESR measurements made by the two laboratories were analysed and then compared. These experiments showed a significant gradient in the absorbed dose delivered to each LMRI dosimeter. The dispersion in each box was easily observable. However, a good agreement between the dosimeters and the alanine powder was observed in a same box.     

Progress in quality control of alanine dosimeters

The ESR/alanine system has been used for different applications, over several years, as a classical routine dosimetry service. This service is based on alanine dosimeters constituted by pellets manufactured by our laboratory, which are presented with some specifications of use and different parameters bound to the intrinsic quality of the dosimeter itself. These parameters were obtained through the strict application of a production protocol and a validation protocol created, tested and validated under a quality assurance system. Every year, one batch of photon dosimeters is produced and controlled using these protocols and the specifications associated with it are checked. Two categories of data are considered separately: physical parameters and experimental data obtained by measurement on our ESR system are given with their associated standard deviation.     

A high malaria reinfection rate in children and young adults living under a low entomological inoculation rate in a periurban area of Bamako,Mali

In areas of intense malaria parasite transmission, preliminary studies of the rate of reinfection after curative therapy suggest that small sample size studies of vaccine efficacy are feasible. However, the effect of transmission rate, which may vary considerably between transmission seasons, on reinfection rate has not been assessed in areas of mesoendemicity with seasonal transmission. To address this question, the Plasmodium falciparum reinfection rate after curative therapy was measured in Sotuba, a Malian village with historically low transmission rates, as estimated by the entomological inoculation rate (EIR). The reinfection rate after curative Fansidar (sulfadoxine-pyrimethamine) treatment was 80.7% (88/109). The EIR during the 13-week study period (seasonal transmission) varied between 1 and 4.5 infected bites/person/month. The finding that reinfection rates were high despite low EIRs suggests that a low EIR may be sufficient to support small sample size vaccine efficacy trials in mesoendemic areas.     

The Impact of Six Annual Rounds of Mass Drug Administration on Wuchereria bancrofti Infections in Humans and in Mosquitoes in Mali

Wuchereria bancrofti prevalence and transmission were assessed in six endemic villages in Sikasso, Mali prior to and yearly during mass drug administration (MDA) with albendazole and ivermectin from 2002 to 2007. Microfilaremia was determined by calibrated thick smear of night blood in adult volunteers and circulating filarial antigen was measured using immunochromatographic card test in children < 5 years of age. Mosquitoes were collected by human landing catch from July to December. None of the 686 subjects tested were microfilaremic 12 months after the sixth MDA round. More importantly, circulating antigen was not detected in any of the 120 children tested, as compared with 53% (103/194) before the institution of MDA. The number of infective bites/human/year decreased from 4.8 in 2002 to 0.04 in 2007, and only one mosquito containing a single infective larva was observed 12 months after the final MDA round. Whether this dramatic reduction in transmission will be sustained following cessation of MDA remains to be seen.     

Fréquence du déficit en glucose-6-phosphate déshydrogénase (A-376/202) dans trois groupes ethniques vivant en zone d’endémie palustre au Mali

Erythrocyte G6PD deficiency is the most common worldwide enzymopathy. The aim of this study was to determine erythrocyte G6PD deficiency in 3 ethnic groups of Mali and to investigate whether erythrocyte G6PD deficiency was associated to the observed protection against malaria seen in Fulani ethnic group. The study was conducted in two different areas of Mali: in the Sahel region of Mopti where Fulani and Dogon live as sympatric ethnic groups and in the Sudanese savannah area where lives mostly the Malinke ethnic group. The study was conducted in 2007 in Koro and in 2008 in Naguilabougou. It included a total 90 Dogon, 42 Fulani and 80 Malinke ethnic groups. Malaria was diagnosed using microscopic examination after Giemsa-staining of thick and thin blood smear. G6PD deficiency (A-^376/202) samples were identified using RFLP (Restriction Fragment Length Polymorphism) assay and analysis of PCR-amplified DNA amplicon. G6PD deficiency (A-^376/202) rate was 11.1%, 2.4%, and 13.3% in Dogon, Fulani, and Malinke ethnic group respectively. Heterozygous state for G6PD (A-^376/202) was found in 7.8% in Dogon; 2.4% in Fulani and 9.3% in Malinke ethnic groups while hemizygous state was found at the frequency of 2.2% in Dogon and 4% in Malinke. No homozygous state was found in our study population.We conclude that G6PD deficiency is not differing significantly between the three ethnic groups, Fulani, Dogon and Malinke.     

Evaluation of p53 protein as a prognostic factor for oral cancer surgery

We have analysed concentrations of the p53 protein in advanced oral carcinomas immunohistochemically and genetically to detect the percentage of overexpression of this antioncogene that indicates a high probability of mutation. This would point to it being a useful prognostic factor, if we consider the importance of the relation between genetic alterations of p53 and poor overall survival. Seventy-five non-consecutive patients with oral squamous cell carcinoma and metastatic nodes were enrolled if there was homogeneity in histopathological grading (G2) of their tumours, and they were treated according to a multidisciplinary treatment plan. Monoclonal antibodies, extraction of DNA, and amplification of the polymerase chain reaction (PCR) were used for the immunohistochemical and genetic analyses. There was a significant inverse correlation between p53 overexpression and response to chemotherapy and a stronger association between high P53 overexpression (%) and a genetic mutation of p53 (p = 0.0001). More than 50% overexpression indicated a strong probability of genetic mutation. There was no association between response to chemotherapy and age-groups or TNM classification (p = 0.2), but there was a significant one between sex and site of tumour (p < 0.001). Three prognostic factors were significantly related to prognosis: site of tumour (p = 0.01), response to chemotherapy (p = 0.002), and immuno p53 (p = 0.0001). A tumour that is characterised by p53 overexpression of more than 50% indicates a poor prognosis.     

Plasminogen activator system modulates invasivecapacity and proliferation in prostatic tumor cells

The malignant phenotype of prostatic tumor cells correlates with the expression of both uPA and itscell-membrane receptor (uPAR); however, there is little information concerning the role of cell-bound uPAin matrix degradation and invasion. Our results suggest that cell-associated uPA plays a key role in regulat-ingthe amount of plasmin present at the surface of prostatic carcinoma (PRCA) cells and show that differ-entialproduction of uPA corresponds with the capacity to bind and activate plasminogen. In addition, weprovide direct evidence that both uPA secretion and the presence of uPA-uPAR complexes characterize theinvasive phenotype of PRCA cells and suggest the existence of several pathways by which tumor cells acquireplasmin activity. LNCaP cells (which do not produce uPA but express uPAR) may activate plasmin throughexogenous uPA. In vivo, the source of uPA may be infiltrating macrophages and/or fibroblasts as observedin several other systems. PAI-1 accumulation in the conditioned medium (CM) limits plasmin action to thepericellular microenvironment. Our results indicate that MMP-9 and MMP-2 are also activated by plasmingenerated by cell-bound but not by soluble, extracellular uPA. Plasmin activation and triggering of the pro-teolyticcascade involved in Matrigel invasion is blocked by antibodies against uPA (especially by anti- A-chainof uPA which interacts with uPAR) and by PA inhibitors such as p-aminobenzamidine which mayregulate levels of cell-bound uPA. uPA may also regulate growth in PRCA cells. Indeed, antibodies againstuPA A-chain (and also p-aminobenzamidine treatment) interfere with the ATF domain and inhibit cell growthin uPA-producing PC3 and DU145 prostate cancer cell lines, whereas exogenous uPA (HMW-uPA with ATF)induces growth of LNCaP prostate tumor cell line. These data support the hypothesis that in prostatic can-cerpatients at risk of progression, uPA/plasmin blockade may be of therapeutic value by blocking both growthof the primary tumor and dissemination of metastatic cells. ©Kluwer Academic Publishers     

The "wingbeat hypothesis" of reproductive isolation between members of the Anopheles gambiae complex (Diptera: Culicidae) does not fly

Recent advances have demonstrated that, in the absence of postmating barriers to hybridization, reproductive isolation between different forms of Anopheles gambiae sensu stricto is maintained by strong assortative mating. The forms of An. gambiae s.s. and the sister species An. arabiensis commonly form mixed swarms in which they mate. This raises the question as to how individuals recognize mates of their own species or form within swarms. It has been proposed that wingbeat frequency is used as a cue to discriminate potential mates. This has important implications for prospective genetic control programs. We used a photosensor to record the transient waveforms generated by individuals An. arabiensis and from the M and S molecular forms of An. gambiae s.s. as they flew through a beam of light. We found no significant between-species or between-form differences in the fundamental harmonic--equivalent to wingbeat frequency--either in males or females collected from sympatric populations in Mali, West Africa. However, there were significant differences in the amplitude of the first and third harmonics in females and of the first and second harmonics in males. Whereas these results suggest some morphological or behavioral differences between species and forms, the extensive overlap in the distributions of harmonic amplitudes does not point to them as reliable cues for assortative mating. Combining all waveforms parameters into a discriminant analysis did not yield characteristic scores either for males or females. Thus, our results do not support the wingbeat hypothesis of premating isolation in the An. gambiae complex.     

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.