The 11p15 region is organised into two independent imprinted domains controlled by imprinting control regions, which carry opposite germline imprints. Dysregulation of 11p15 genomic imprinting results in two human fetal growth disorders (Silver-Russell syndrome (SRS, MIM 180860) and Beckwith-Wiedemann syndrome (BWS, MIM 130650)) with opposite growth phenotypes. The mouse orthologous region on distal chromosome 7 (dist7) is well conserved in its organisation and its regulation. Targeted mutagenesis in mice has provided highly valuable clues in terms of the mechanisms involved in the regulation of genomic imprinting of the 11p15/dist7 imprinted region. On the other hand, the recent identification of unexpected genetic defects in BWS and SRS patients also brought new insights into the mechanisms of 11p15 imprinting regulation. However, some mouse models and human genetic defects show contradictions in term of growth phenotypes and parental transmission. In this review, we extensively analyse those various mouse and human models and more particularly models with mutations affecting the two imprinting centres, in order to improve our understanding of regulation of 11p15/dist7 genomic imprinting. arabic 21 English 117
Mansur Ennuri Moftah Shmela, C. F. Gicquel(1-2013)

On March 2013, the Libyan poultry industry faced severe outbreaks due to mixed infections of APMV-1 (Newcastle disease) and low pathogenic avian influenza (AI) of the H9N2 subtype which were causing high mortality and great economic losses. APMV-1 and H9N2 were isolated and characterized. Genetic sequencing of the APMV-1/chicken/Libya/13VIR/ 7225-1/2013 isolate revealed the presence of a velogenic APMV-1 belonging to lineage 5 (GRRRQKR*F Lin.5) or genotype VII in class II, according to the nomenclature in use. Three AI viruses of the H9N2 subtype, namely A/avian/Libya/13VIR7225-2/2013, A/avian/Libya/13VIR7225-3/2013, and A/avian/Libya/13VIR7225-5/2013, were isolated and found to belong to the G1 lineage. Analysis of amino acid sequences showed that the analyzed H9N2 viruses contained the amino acid Leu at position 226 (H3 numbering) at the receptor binding site of the HA, responsible for human virus-like receptor specificity. On March 2014, an outbreak of highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was diagnosed in a backyard poultry farm in an eastern region of Libya. The H5N1 isolate (A/chicken/Libya/14VIR2749-16/2014) was detected by real time RT-PCR (rRTPCR). Genetic characterization of the HA gene revealed that the identified subtype was highly pathogenic, belonged to the 2.2.1 lineage, and clustered with recent Egyptian viruses. This study revealed the presence of a velogenic APMV-1 genotype and of two influenza subtypes, namely HPAI H5N1 and H9N2, which are of major interest for public and animal health. Considering these findings, more investigations must be undertaken to establish and implement adequate influenza surveillance programs; this would allow better study of the epidemiology of APMV-1 genotype VII in Libya and evaluation of the current vaccination strategies.
Abdulwahab Kammon(5-2015)

The present study aimed at evaluation of the immuomodulatory effect of sulphadimidine by investigating its ability to affect constitutive expression of MHC-II molecules on B-cells, which are one determinant of antigen presentation and the vigor of immunity. Three groups of broiler chicken were used, the first two groups received 100 mg/kg and 200 mg/kg sulfadimidine, respectively, in drinking water; while the third group was left as control. Bursal samples were taken after 7 and 14 days of treatment and checked for MHC-II gene expression by RT-PCR technique. The obtained results demonstrate that oral administration of sulphadimidine inhibited the expression of MHC-II mRNA in bursal of Fabricius of broiler chicken in a dose and age dependent manner. This finding is of clinical importance as many farmers routinely add sulpha drugs to drinking water as a prophylactic measure against some infections; yet the data presented in this study doesn't recommend this managing behavior. arabic 11 English 83
Marwan Draid(5-2012)