Evaluation using GEANT4 of the transit dose in the Tunisian gamma irradiator for insect sterilization.

A simulation study of the Tunisian Gamma Irradiation Facility for sterile insects release programs has been realized using the GEANT4 Monte Carlo code of CERN. The dose was calculated and measured for high and low dose values inside the irradiation cell. The calculated high dose was in good agreement with measurements. However, a discrepancy between calculated and measured values occurs at dose levels commonly used for sterilization of insects. We argue that this discrepancy is due to the transit dose absorbed during displacement of targets from their initial position towards their irradiation position and displacement of radiation source pencils from storage towards their irradiation position. The discrepancy is corrected by taking into account the transit dose.     

Isolation and Characterization of Lytic Pseudomonas aeruginosa Bacteriophages Isolated from Sewage Samples from Tunisia

Bacteriophages could be a useful adjunct to antibiotics for the treatment of multidrug-resistant Pseudomonas aeruginosa infections. In this study, lytic P. aeruginosa myoviruses PsCh, PsIn, Ps25, and Ps12on-D were isolated from Tunisian sewage samples. Phage Ps12on-D displayed an adsorption time of ~10 min, a short latency period (~10 min), and a large burst size (~115 PFU per infected cell) under standard growth conditions. All phages were active at broad temperature (4 °C to 50 °C) and pH (3.0 to 11.0) ranges and were able to lyse a wide variety of P. aeruginosa strains isolated from clinical and environmental samples worldwide. Illumina sequencing revealed double-stranded DNA genomes ranging from 87,887 and 92,710 bp with high sequence identity to Pseudomonas phage PAK_P1. All four phages based on sequence analysis were assigned to the Pakpunavirus genus. The presented characterization and preclinical assessment are part of an effort to establish phage therapy treatment as an alternative strategy for the management of multidrug-resistant P. aeruginosa infections in Tunisia.     

Photocatalytic Activity of Silicon Nanowires Decorated with PbS Nanoparticles Deposited by Pulsed Laser Deposition for Efficient Wastewater Treatment

The present work aims to study the photocatalytic properties of nanohybrids composed of silicon nanowires (SiNWs) decorated with PbS nanoparticles (NPs). The elaborated material was intended to be utilized in wastewater treatment. The SiNWs were elaborated from the Metal Assisted Chemical Etching route (MACE), while the PbS NPs were deposited at room temperature onto SiNWs using the pulsed laser deposition (PLD) technique. The influence of decorating SiNWs (having different lengths) with PbS-NPs on their structural, morphological, optoelectronic, and photocatalytic properties was scrutinized. PbS/SiNWs nanohybrids exhibited enhanced photocatalytic degradation towards Black Amido (BA) dye for 20 µm SiNWs length and 0.2% of BA volume concentration. These optimized conditions may insinuate that this nanocomposite-like structure is a promising efficient photocatalytic systems contender, cost-effective, and recyclable for organic compound purification from wastewaters.     

Hibiscus sabdariffa increases hydroxocobalamin oral bioavailability and clinical efficacy in vitamin B12 deficiency with neurological symptoms

The aim of the study was to evaluate the bioavailability and clinical benefits of oral new formulation (HB₁₂) of hydroxocobalamin (Hdrx) with Hibiscus sabdariffa (HS). First, in an observational study, a cohort of 30 vitamin B₁₂‐deficient patients (vit B₁₂ < 200 pg/mL) with neurological symptoms received oral fixed dose of Hdrx containing 15 mg Hdrx daily for 10 days followed by 15 mg monthly. Clinical benefits were evaluated on haematological and biochemical parameters, and neurological improvement at days 10 and 90 compared to day 0. To understand the mechanism, intestinal mucosa from mice were mounted in vitro in Ussing chambers to measure Hdrx Fluxes. In the clinical study, serum vitamin B₁₂ level increased from 55.1 ± 36.9 to 1330 ± 335.5 pg/mL at day 10 and 431.0 ± 24.27 pg/mL at day 90, without overt adverse effects. In mice ileum, (i) intestinal bioavailability of Hdrx increased in dose‐dependent manner with HB₁₂. The apparent permeability of Hdrx was P_app = 34.9 ± 4.6 × 10^?6 cm/s in the presence of 3 mg/mL (HB₁₂B) compared to the control P_app = 6.2 ± 0.7 × 10^?6 cm/s. (ii) Total transepithelial electrical conductance (G_t) increased in dose‐dependent manner with HB₁₂, G_t = 161.5 ± 10.8 mS/cm² with HB₁₂B (Hdrx 1 mg + HS 3 mg) compared to the control Hdrx, G_t = 28.7 ± 4.0 mS/cm². In conclusion, the clinical study suggests that injections are not required when Hdrx is given orally. Intestinal bioavailability of Hdrx increased in vitro when it was used concomitantly with HS.     

SLC26A4 variations among Graves' hyper-functioning thyroid gland

Deleterious mutations of SLC26A4 cause Pendred syndrome (PS), an autosomal recessive disorder comprising goitre and deafness with enlarged vestibular aqueducts (EVA), and nonsyndromic hearing loss (NSHL). However, the SLC26A4 hyperactivity was recently associated with the emergence of autoimmune thyroid diseases (AITD) and asthma among human and mouse model. Here, by direct sequencing, we investigate the sequences of the 20 coding exons (2 to 21) of SLC26A4 and their flanking intron-exon junctions among patients affected with Graves' disease (GD) hyperthyroidism. Ten mono-allelic variants were identified, seven of which are intronic and previously unreported. Two, c.898A>C (p.I300L) and c.1061T>C (p.F354S), of the three exonic variants are non synonymous. The p.F354S variant is already described to be involved in PS or NSHL inheritances. The exploration by PCR-RFLP of p.I300L and p.F354S variants among 132 GD patients, 105 Hashimoto thyroiditis (HT), 206 Healthy subjects and 102 families with NSHL have shown the presence of both variants. The p.F354S variation was identified both among patients (1~HT and 3 GD) and healthy subjects (n=5). Whereas, the p.I300L variant was identified only in GD patients (n=3). Our studies provide evidence of the importance of systematic analysis of SLC26A4 gene sequences on models other than deafness. This approach allows the identification of new variants and the review of the pathogenic effects of certain mono-allelic variants reported responsible for PS and NSHL development.     

Influence of Common and Specific HLA-DRB1/DQB1 Haplotypes on Genetic Susceptibilities of Three Distinct Arab Populations to Type 1 Diabetes

The contribution of HLA DRB-DQB to type 1 diabetes (T1D) in Bahrainis, Lebanese, and Tunisians was investigated. DRB1*030101-DQB1*0201 was a locus that conferred susceptibility in three populations, while DRB1*040101-DQB1*0302 was a locus that conferred susceptibility only in Tunisians and Bahrainis. The DRB1*100101-DQB1*050101 (Bahrainis) and DRB1*150101-DQB1*060101 (Lebanese) loci were largely protective. The contribution of HLA to T1D must be evaluated with regard to ethnic background.