[Rubella seroprevalence in Tunisian childbearing women two years after vaccination program introduction]. / Séroprévalence de la rubéole chez la femme en âge de procréer deux ans après l'introduction de la vaccination en Tunisie.

UNLABELLED: Acquiring rubella during the first 20 weeks of pregnancy can lead to teratogenic effects. AIM: The aim of the study was to investigate the impact of rubella vaccination strategy two years after its introduction in Tunisia in 2005. METHODS: This study was conducted over two periods, 2000 and 2007-2008. A total of 15,776 childbearing women were enrolled in the sample. Serological studies were performed by using the ELISA method. RESULTS: Overall, rubella infection seroprevalence did not increase between 2000 and 2007-2008. Nevertheless, a significant increase in seroprevalence, from 78.2% in 2000 to 92% in 2007-2008 (P=0.006), was especially noted in the age group under 20 years. Seroprevalence did also statistically increase with parity in 2007-2008 from 77.4% in women without any parity to 89.8% in women with over three parities (P=0.01). CONCLUSIONS: Results improvements seem most likely due to mass vaccination campaign for girls aged from 13 to 18 years in 2005, and also routinely post-partum vaccination of seronegative pregnant women or women ignoring their rubella status. In the coming years, systematic selective immunization of 12-year-old schoolgirls who are not yet entering their prime childbearing years will achieve female population sufficient immunity.

[Significance of "anti HBC alone" serological profile in 284 patients suspicious of being infected with hepatitis B virus]. / Signification du profil sérologique "anticorps anti-HBC isolés" chez 284 patients suspects d'être infectés par le virus de l'hépatite B.

The "anti-HBc alone" serological profile is a frequent finding in hepatitis B virus infections, but little is known about its clinical significance. The aim of this study was to explore the 'anti-HBc alone' serological profile obtained by immunosorbent assay (ELISA) in 284 patients suspicious of being infected with hepatitis B virus. Sera were screened for following serological markers: HBs Ag, anti-HBc and anti-HBs antibodies using immunoradiometric assay (IRMA) and for HBV DNA using polymerase chain reaction. Among 284 studied sera with 'anti-HBc alone' serological profile, 124 were positives for anti-HBs antibodies by IRMA and corresponding to a recovered form of hepatitis B. Nineteen sera were negatives for anti-HBc antibodies, suggesting false positive results by ELISA. Two sera were found positives for HBs Ag by IRMA, which are related to authentic hepatitis B. HBV DNA was positive in 4 sera, suggesting occult hepatitis B. This study indicates that "anti-HBc alone" serological profile is most often correlates with recovered hepatitis B infection, but it can mask an occult hepatitis B.

[North African and Southeast Asian nasopharyngeal carcinomas: between the resemblance and the dissemblance]. / Le carcinome nasopharyngé en Afrique du Nord et dans le Sud-Est asiatique: entre similitude et différence.

Nasopharyngeal carcinoma (NPC) is an unusual head and neck cancer because of its unequal geographical distribution and its consistent association with the Epstein-Barr virus (EBV). This malignant tumor poses a serious public health problem in many countries, especially in Southeast Asia and North Africa where the recorded incidence are highest. During the past decade, a growing number of studies were undertaken to define the molecular basis of NPC. However, the analysis of several clinical and biological parameters of North African and Southeast Asian NPCs has shown notable differences, suggesting that they could result from a distinct combination of etiological factors. One intriguing characteristic of North African NPC, concerns its bimodal age distribution with a secondary peak of incidence in the range of 15-25 years, not observed in Asian NPC. In this juvenile form of NPC, immuno-histochemistry assay has shown that the two key proteins controlling the apoptotic-survival balance p53 and Bcl-2 are less frequently expressed whereas the transmembrane tyrosine-kinase receptor c-kit and the main EBV oncoprotein LMP1 were more abundant. In addition, the EBV serological alterations are less informative for the diagnosis of the juvenile compared to the adult form. In addition, most North African NPCs contain EBV strains with genetic polymorphisms distinct from those described in the Southeast Asia series (predominance of F, D, H1-H2, XhoI+ and f, C, H, XhoI- respectively). In contrast, studies relating on tumor chromosomal alterations or aberrant promoter methylation result in data very similar to those obtained from the Southeast Asia series, supporting the concept of a common molecular basis for all NPC regardless of patient geographic origin.

Comparison of three different serological techniques for primary diagnosis and monitoring of nasopharyngeal carcinoma in two age groups from Tunisia.

Nasopharyngeal carcinoma (NPC) in Tunisia is characterized by its bimodal age distribution involving juvenile patients of 10-24 years and adult patients of 40-60 years. Three serological techniques were compared for primary diagnosis (N = 117) and post-treatment monitoring (N = 21) of NPC patients separated in two age groups. Immunofluorescence assay (IFA) was used as the "gold standard" for detection of IgG and IgA antibodies reactive with Epstein-Barr virus (EBV) early (EA) and viral capsid (VCA) antigens. Results were compared with ELISA measuring IgG and IgA antibody reactivity to defined EBNA1, EA, and VCA antigens. Immunoblot was used to reveal the molecular diversity underlying the anti-EBV IgG and IgA antibody responses. The results indicate that young NPC patients have significantly more restricted anti-EBV IgG and IgA antibody responses with aberrant IgG VCA/EA levels in 78% compared to 91.7% in elder patients. IgA VCA/EA was detected in 50% of young patients versus 89.4% for the elder group (P < 0.001). Immunoblot revealed a reduced overall diversity of EBV antigen recognition for both IgG and IgA in young patients. A good concordance was observed between ELISA and IFA for primary NPC diagnosis with 81-91% overall agreement. Even better agreement (95-100%) was found for antibody changes during follow-up monitoring, showing declining reactivity in patients in remission and increasing reactivity in patients with persistent disease or relapse. ELISA for IgA anti-VCA-p18 and immunoblot proved most sensitive for predicting tumor relapse. VCA-p18 IgA ELISA seems suitable for routine diagnosis and early detection of NPC complication.

An optimised protocol for plant regeneration from embryogenic suspension cultures of date palm, Phoenix dactylifera L., cv. Deglet Nour.

An improved protocol is described for the large-scale micropropagation of an elite date palm ( Phoenix dactylifera L.) cultivar, Deglet Nour. Clonal plants were regenerated from somatic embryos derived from highly proliferating suspension cultures. Friable embryogenic calli were initiated from both leaf and inflorescence explants. Suspension cultures consisting of pro-embryonic masses were established from calli showing a high competency for somatic embryogenesis. The subculture of suspensions in liquid medium enriched with low amounts of plant growth regulators (1 mg l(-1) 2,4-dichlorophenoxyacetic acid with 300 mg l(-1) charcoal) resulted in the differentiation of large numbers of somatic embryos. The productivity of the cultures increased 20-fold (from 10 to 200 embryos per month per 100 mg fresh weight of embryogenic callus) when embryogenic suspensions were used instead of standard cultures on solid media. The overall production of somatic embryos reached 10,000 units per litre per month. Partial desiccation of the mature somatic embryos, corresponding to a decrease in water content from 90% to 75%, significantly improved germination rates (from 25% to 80%). The cutting back of the cotyledonary leaf was also found to stimulate embryo germination. Flow cytometric analysis showed that the micropropagation protocol followed here did not affect the ploidy level of somatic embryo-derived plantlets.