Archives de l'Institut Pasteur de Tunis最新文献

Methanolic extracts of 13 seaweeds collected from the Mediterranean sea (Tunisian, Moroccan and Greek coasts) from different classes (Chlorophycae, Pheopbycae and Rhodophycae) are testedfor their analgesic and antiinflammatory effects. These activities were estimated in vivo, respectively by writhing test and carrageenan test. Nine species among 13 tested seaweeds showed an important analgesic activity. On the other hand only 5 seaweeds showed a significant anti-inflammatory activity (< 0.001 compared to control group). The percentage of inhibition reached 80% for the red algae Laurencia glandulifera but was only 50% for aspirin. The screening showed different pharmacological profiles. The red algae (Laurencia glandulfera and Hypnea musciformis) and brown algae (Cystoseira barbata and Sargassum vulgare) had endowed with the double analgesic and anti-inflammatory activity. The red algae Geliduim sesquipedale have only anti-inflammatory activity and the other one endowed only with an analgesic activity (Enteromorpha compressa, Chaetomorpha linum, Cystoseira ericoidies, Sacchoriza bulbosa et Corralina officinalis). The simultaneous or individual presence of the analgesic andor anti-inflammatory activities of the various extracts can find its application in the therapeutic domain.

Crohn's disease (CD) and ulcerative colitis (UC) have complex genetic background that is characterised by more than one susceptibility locus. To detect a possible association between the functional polymorphisms of the chemokine receptors CCR5, CCR2 and MCP-1 genes and susceptibility to CD and UC in Tunisian population, polymorphisms of CCR5-delta32, CCR5-59029-A/G, CCR2-V641 and MCP-1-2518-G/A were analysed in 194 Inflammatory bowel disease (IBD) patients and 169 healthy blood donors using PCR-RFLP and PCR-SSP methods. The patients were classified in 126 patients with CD and 68 patients with UC. The genotypic and allelic frequencies of all polymorphisms studied, did not reveal significant differences between patients and conrols and among CD and UC patients. However, analysis of CD patients revealed that those without homozygosous G/G genotype are more frequently in remission compared to those with this genotype (OR: 0.4, 95% CI: [0.174-0.928]; p = 0.03). Also, the frequency of the CCR2-641 muted allele was statistically higher in CD patients in remission disease than those in active form (OR: 0.267 95% CI: [0.09-0.78]; p = 0.01). Adjustment for known covariates factors (age, gender and immunosuppressive regimen) confirmed these univariate findings and revealed that the CCR5-59029-A/G and CCR2-V64I genotype were associated to remission form of CD (OR: 263; 95% CI: [1.01-6.80]; p = 0.047 and OR: 4.64; 95% CI: [1.01-21.31]; p = 0.049 respectively). In conclusion, the present study supports the involvement of chemokine receptor (CCR2 and CCR5) polymorphisms in activity degree of the IBD disease in Tunisian patients.

We report the case of a 35-year-old Tunisian women with a chronic anemia non investigated for a long time. Laboratory analysis using advanced technology of DNA sequencing revealed a compound heterozygote for Hb O Arab and cd 39 beta degrees-thalassemia. It's the first time that such a genotype has been characterized by gene sequencing.

Selectins belong to the family of adhesion molecules that recognize sugars as ligands through their Carbohydrate Recognition Domain (CRD). There are three types of selectin: the L-selectin (CD62L), which is constitutively expressed by most leukocyte populations, the P-selectin (CD62P) is found on activated platelets and endothelial cells, and the E-selectin (CD62E) expressed by activated endothelial cells. These three molecules exhibit high homology in their structures. Selectin-ligand interactions are among the most studied protein-glycan interactions in biology. The selectins and theirs ligands are involved in regulating inflammatory and immunological events that occur at the interface of the bloodstream and vessel walls. Their molecular partners are surface glycoconjugates harboring groups of the sialyl-Lewis antigens. This review presents an inventory of our current knowledge on the structures and functions of selectins and their ligands. We also provide an update on their involvement in pathophysiological processes, especially during inflammation and tumor development.

In order to survey osmotic and oligotrophic stress consequence on pathogenic enterobacteria discharged in marine areas, we examined enterotoxigenic Escherichia coli (ETEC) and a reference (Ecoli O126:B16) strains during their survival (47 days) in wastewater microcosms, submerged in natural seawater and maintained in laboratory conditions. The results revealed that the survival time for the two strains was prolonged when bacterial cells were previously incubated in wastewater, with less cellular membrane damage. In addition, the wild clinical E. coli strain showed a better survival capacity than the reference E. coli strain one. For both, we noted some modifications in biochemical profiles relatively to the initial state, notably when they were previously incubated in wastewater microcosm.

Aluminium and indium are two elements used in industrial and medical fields. The purpose of this work was to study the subcellular localization of these elements, after their single and simultaneous oral administration to rats. 2h after the administration of these two elements, the small intestine and the liver were removed.Ultrastructural study showed the presence of electron dense deposits in the lysosomes of apical parts of duodenal enterocytes. When the minerals were administered simultaneously, deposits were observed in lysosomes of duodenal and jejunal enterocytes. No deposits were seen in the hepatic tissue of treated and control rats. Microanalysis identification showed that the deposits are constituted of aluminium, indium as well as phosphorus. Our results suggested that the elements are concentrated, in lysosomes, under the form of insoluble phosphate salts and it seemed that there are no specific lysosomes for the concentration of minerals since the two elements were concentrated in the same lysosome when they are administered simultaneously.

We conducted a retrospective study of meningococcal invasive diseases (MID) contracted in children in Tunis between January 1997 and January 2006. The purpose of this study is to specify the clinical, epidemiological, therapeutic and evolutionary features of these infections and to determine antimicrobial susceptibility and the antigenic formula of N. meningitidis isolates. During the study period, we have collected 79 cases of MID arising in children aged 3 days to 11 years. The majority of children's were less than of 4 years (57.3%). We note a frequency of the MID in winter and in spring. The most frequent clinical shape was meningitis (53%). Twenty one patients (26.6%) had a fulminant meningococcal disease. In our series, the rate of lethality was equal to 17.7%. Among the 46 meningococcal isolates, the most frequent serogroup was the B (73%) followed by C and A. A high heterogeneousness of the antigenic formulae was observed The most frequent phenotype was NT: NST for the group B isolates and 4:P1.13 for the group C ones. N meningitidis with reduced susceptibility to penicillin and to amoxicillin account for 54% and 10% of all isolates respectively. The cefotaxim and the rifampin were uniformly active.

The UDP-glucuronosyltransferase 1A1 gene that encode the enzyme UGT1A1 responsible for glucuronidation undergoes several variations that may affect the enzymatic activity or expression and which are the cause of metabolic disorders related to the glucuronidation of bilirubin, such as Gilbert's syndrome and Crigler Najjar's syndrome. Among the most common variations, there is the repeat polymorphism A (TA) n TAA in TATA box and biallelic mutation G211A in exon 1. We consider in this work to determine their frequencies in a healthy population. The polymorphism A (TA) n TAA showed that genotype [TA7/TA7] was described as being associated with Gilbert's syndrome and was encountered in 11% of the population studied. This percentage is close to the value described in the Caucasian population, estimated at 10%. Concerning the polymorphism G211A, our results show that the mutated allele is encountered in 15.7% of our study population. This frequency differs greatly from that reported for Caucasians and Afro-Americans but it is similar to that perceived at the Japanese. All these results suggest that the Tunisian population appears to be heterogeneous view UGT1A1 gene mutation status. Regarding the origins and distribution of such polymorphisms in our population, the study reveals a high haplotypic haplotype (TA) 6-G considered ancestral. The comparison of the haplotype structure generally leads to the development of a hypothetical tree of the origin and spread of different haplotypes.

The food handlers control is one of the major measures of the National program against intestinal parasitoses in Tunisia. The collected data allow regular updates of the prevalence and profile of the involved parasitic species and note possible evolutions in time. From 1998 to 2008, 8502 stool samples of food handlers working in Tunis area were examined in the laboratory of Parasitology, Pasteur Institute of Tunis. The mean prevalence of intestinal parasites was 13.5% (1152 positive samples). The protozoa were the most detected parasites (93% of the species observed). Among the pathogenic or potentially pathogenic parasites, Dientamoeba fragilis (15.5%) and Giardia intestinalis (7.6%) were the most frequently encountered. Entamoeba (E.) histolytica/dispar was diagnosed in 41 subjects (a prevalence of 05%). Hymenolepis nana was the most frequent helminth (45% of the whole parasites). Therapeutic failures were noticed in 43.8% of infection by this cestode because of the lack of the appropriate antihelminthic. The identification using PCR of cysts and/or vegetative forms of E. histolytica/dispar revealed the exclusive presence of E. dispar.

To investigate the relationship between the soluble HLA-G (sHLA-G) and the appearance of acute renal rejection (AR) episodes we have quantify in this study the level of sHLA-G by enzyme-linked immunosotrbent assay in 42 kidney transplant patients classified in two groups: G1: 17patients with acute rejection (AR+) and G2: 25 patients without AR (AR-). To establish our normal sHLA-G ranges, serum samples from 18 healthy controls were tested. Pre-transplantation sHLA-G levels were significantly increased in patients (mean +/- standard error of the mean, 60.48 +/- 12.18 units/ml) than healthy subjects (19.11 +/- 4.9 units/ml) (p = 0.001). Although the difference was not statistically significant, G1 patients (AR+) revealed lower levels of sHLA-G (mean +/- standard error of the mean, 31.25 +/- 6.71 units/ml) compared to G2 patients (AR-) (53.43 +/- 1721 units/ml). Nevertheless, the course of total sHLA-G levels was nearly identical in patients with and without rejection. Nonparametric analysis revealed that pre-transplantation levels of sHLA-G < 18.00 units/ ml (sensitivity: 87.8% and specificity of 72.2%) were not related to rejection. Also, multivariate analysis regarding anti-HLA antibody status, recipient age and gender showed that sHLA-G could not be an independent risk factor for renal graft rejection. However, a higher sera levels of sHLA-G seemed to contribute to better kidney allograft survival rate after 10 years of follow-up (significance tendency: p = 0.091) as shown by the survival analysis. Because of the small number of subjects studied, these results must be treated with caution. A much larger cohort of kidney transplant patients according to acute rejection would seem necessary to confirm these findings.