Mohammed Hassar

The Pro variant of the p53 codon 72 polymorphism is associated with hepatocellular carcinoma in Moroccan population

Aim:  Codon 72 polymorphism of the p53 gene has been implicated in cancer risk, and it has been suggested that it may have an impact on the clinical outcome of the disease. Our objective was to evaluate the association between p53 polymorphism at codon 72 and hepatocellular carcinoma (HCC) in the Moroccan population.

New analysis of the toxic compounds from the Androctonus mauretanicus mauretanicus scorpion venom

Scorpion venoms are very complex mixtures of molecules, most of which are peptides displaying different kinds of biological activity. Indeed, these peptides specifically bind to a variety of pharmacological targets, in particular ionic channels located in prey tissues, resulting in neurotoxic effects. Toxins modulating Na+, K+, Ca2+ and Cl(-) currents have been described in scorpion venoms. In this work, we have used several specific antibodies raised against the most lethal scorpion toxins already described to screen the Moroccan scorpion Androctonus mauretanicus mauretanicus venom in order to characterize new compounds. This immunological screening was also implemented by toxicity tests in mice and with mass spectrometry study, providing new informations on the molecular composition of this venom. In fine, we were able to determine the molecular masses of 70-80 different compounds. According to the immunological data obtained, many toxins cross-react with three sera raised against the most lethal alpha-toxins found in North African scorpion venoms, but not at all with those raised against the main beta-toxins from South and North American venoms. Some of the previously described toxins from Androctonus mauretanicus mauretanicus venom could thus be detected by combining immunological tests, toxicity in mice and molecular masses. Among these toxins, one of them, which showed a mild cross-reaction with the serum raised against AaH I (a highly potent toxin from the venom of Androctonus australis), was identified as Amm III and fully sequenced.

Intraspecific variability and pharmacokinetic characteristics of Androctonus mauretanicus mauretanicus scorpion venom

We evaluated the degree of venom toxicity and protein content of several specimens of Androctonus mauretanicus mauretanicus. The quantity of protein of individual venom obtained after manual extraction from 31 different scorpions varied from a minimum of 0.15 mg to a maximum of 1.53 mg. We determined the venom toxicity, in mice, by estimating the number of LD(50)s of 20 scorpions chosen randomly among the 31 scorpions. It ranged from less than 40 LD(50)s to a maximum of 272 LD(50)s. The correlation between protein content and venom lethality is not systematic. We also determined the pharmacokinetics of the venom and its specific anti-venom in rabbits to compare their distribution and elimination properties. After a subcutaneous injection, high concentrations of venom were measured by ELISA in the vascular space rapidly after the injection (T(max) = 0.5 h). The terminal half-life was 2.8 h, close the one determined after intravenous injection (t(1/2beta) = 3.2 h). The total volume of distribution (Vd(ss) or Vd(beta)) was between 317 and 380 ml/kg. The total body clearance was 82 ml/kg/h. For scorpion anti-venom, the terminal half-life, after intravenous injection, was 20.25 h; the volume of distribution was 83 ml/kg and the total body clearance was 3 ml/kg/h. After intramuscular administration, T(max) was reached at 36 h. The results show that venom lethality varies from specimen to specimen and that pharmacokinetic parameters of venom and anti-venom are totally different. This must be taken under consideration in anti-venom production (anti-venom titre) as well as in therapeutic protocols (dose, injection route) to improve serotherapy.

Polymorphisms in antioxidant defence genes and susceptibility to hepatocellular carcinoma in a Moroccan population

Abstract Reactive oxygen species have been related to the aetiology of cancer as they are known to be mitogenic and therefore capable of tumour promotion. The aim of this study was to assess the role of common variation in three polymorphic genes (MnSOD Ala-9Val, GPX1 Pro198Leu and CAT −262 C > T) coding for antioxidant defence enzymes in modulating individual susceptibility to hepatocellular carcinoma (HCC) using a case-control study (cases = 96 and controls = 222). PCR-RFLP and sequencing methods were used to determine the genotype. Overall, there were no associations between genotypes GPX1 and HCC risk (OR, 1.16; 95% CI, 0.56–2.42; p = 0.685). The MnSOD Ala/Ala and CAT TT genotypes were more frequent in HCC than in control (p = 0.001 and p = 0.072, respectively). Further analyses stratified by gender or HCV infection revealed that men and HCV-infected patients carrying CAT TT genotype had a higher risk to develop HCC when compared with controls (OR = 15.94; 95% CI, 3.48–72.92; p < 0.000001 and 12.01; 95% CI, 0.64–223.63, p = 0.056, respectively). Combined MnSOD Ala/Ala and GPx1 Leu/Leu had a synergistic effect on HCC risk, with an OR of 3.84 (p = 0.029). Furthermore an even more pronounced risk was observed when we combined MnSOD Ala/Ala and CAT TT (OR = 13.60, p = 0.023). It appears that variants in MnSOD, CAT or GPX1 have an influence on HCC risk in this cohort. Furthermore, it is possible that cumulative defects in protection from oxidative stress may result in increased risk of liver cancer in the Moroccan population.

Genotype determination in Moroccan hepatitis B chronic carriers.

BACKGROUND In Morocco, chronic liver disease related to hepatitis B virus (HBV) is a public health burden. Treatment of chronic hepatitis B is often complicated by the appearance of escape mutants after treatment with nucleoside analogs, especially with genotypes responsible for the more severe form of the disease. OBJECTIVES In the present study we investigate the prevalence of the different HBV genotypes in Morocco since no previous careful study has been attempted. METHODS Epidemiological data from 91 chronically infected patients (45 women and 46 men) were collected prospectively. Sera were tested for anti-HBc IgG, HBeAg, anti-HBe antibody and liver enzymes. Restriction Fragment Length Polymorphism (RFLP) analysis was confirmed by subsequent sequencing of the pre-S and S region of the viral genome in order to determine which HBV genotypes were prevalent among Moroccan patients. RESULTS The mean age was 41+/-12.4 years. Ten patients (11%) were positive for hepatitis B e antigen (HBeAg) and 81 (89%) were positive for anti-HBe antibodies. By the RLFP method, genotype D, pattern D2, was found in the 77 cases where HBV was successfully amplified. Phylogenetic analysis based on pre-S/S sequences revealed that genotype D in Morocco differed from others D strains subgenotypes (D1, D2, D3 and D4). In addition, the pre-core mutant defined as HBeAg-negative/anti-HBe-positive and HBV DNA positive was detected in 86% of cases. CONCLUSIONS Our results clearly show that genotype D and pre-core mutant are highly prevalent in Morocco.

MDM2 SNP309T>G polymorphism and risk of hepatocellular carcinoma: A case–control analysis in a Moroccan population

BACKGROUND The Murine double minute 2 (MDM2) gene encodes a negative regulator of the p53 tumor suppressor protein. A single nucleotide polymorphism (SNP) in the MDM2 promoter (a T to G exchange at nucleotide 309) has been reported to produce accelerated tumor formation. The aim of this study was to investigate whether this functional SNP is associated with an enhanced risk of liver tumorigenesis in Moroccan patients. METHODS The study consisted in the comparison of 96 hepatocellular carcinomas (HCC) cases and 222 controls without HCC matched for age, gender and ethnicity. PCR-RFLP and sequencing methods were used to determine the genotype at the MDM2 SNP309T>G locus. RESULTS Overall, our results indicate that the GG genotype of SNP309 is significantly associated with an increased risk of HCC (odds ratio, OR=2.60, 95% CI, 1.08-6.28). Interestingly, despite a wide range of confidence interval, there is a trend associating the GG genotype with a high risk of HCC in males (OR=3.31; 95% CI, 0.93-11.82) and in HCV-infected patients (OR=3.7; 95% CI, 0.82-16.45). By contrast, no association between age at diagnosis and MDM2 SNP309 genotypes was observed in HCC patients (P=0.610). CONCLUSION Our findings suggest that the MDM2 309T>G polymorphism is an important modulator of hepatocellular carcinoma development in Moroccan patients.

Single nucleotide polymorphism in DNMT3B promoter and its association with hepatocellular carcinoma in a Moroccan population

Hepatocellular carcinoma is a major malignant tumor characterized in all areas by the disparity of risk between genders. The molecular bases of such disparity are still poorly understood. DNA-methyltransferase-3B (DNMT3B) may play an oncogenic role during tumorigenesis, and its genetic variants have been consistently associated with risk of several cancers, but a single study has investigated their roles in hepatocellular carcinoma (HCC). Polymorphisms of the DNMT3B gene may influence its activity on DNA methylation in several cancers, thereby modulating susceptibility to tumorigenesis. To test this hypothesis, we investigated the association between single nucleotide polymorphism -149C>T (rs2424913) in the promoter region DNMT3B and risk of HCC in a Moroccan population. In this case-control study, the DNMT3B SNP was genotyped by polymerase chain reaction-restriction fragment length polymorphism in 96 HCCs patients and 222 healthy controls that matched for age, sex and ethnicity. Overall, we found that, the DNMT3B 149 TT genotype was not significantly associated with increased risk of HCC (adjusted odds ratio (OR), 0.86, 95% CI, 0.41-1.80, P=0.697). Stratification analysis detected, however, a trend towards a profound risk in the female subset of patients (OR=2.04, 95% CI, 0.77-5.42) and a lesser risk for HCV-infected patients (OR=1.33, 95% CI, 0.43-4.17). Our findings contrast with those of previous studies performed in various cancers, which showed that individuals carrying at least one T allele have a significantly increased risk of developing cancer. In addition, we provide genetic evidence for the major difference of HCC risk between men and women. Further mechanistic studies are needed to unravel the underlying molecular mechanisms.

Prevalence of Common HFE and SERPINA1 Mutations in Patients with Hepatocellular Carcinoma in a Moroccan Population

BACKGROUND Hereditary hemochromatosis and SERPINA1 mutation were reported to affect liver functions. Our objective was to estimate the prevalence of HFE and SERPINA1 (formerly known as alpha1-antitrypsin, AAT) mutations and assess their influence on hepatocellular carcinoma development. METHODS This study included 222 controls and 96 cases with hepatocellular carcinoma. PCR-RFLP was used to characterize S and Z alleles in SERPINA1, as well as C282Y/H63D alleles of HFE. RESULTS In healthy subjects and hepatocellular carcinoma patients as well, no homozygotes for the C282Y mutation were found. In controls, heterozygosity and homozygosity for the H63D mutation were 27 and 0.9%, respectively. Among patients, homozygosity for the H63D mutation was 3.1%, whereas heterozygosity for C282Y and H63D was 2.1 and 35.4%, respectively. Interestingly, albeit it does not reach significance (p=0.062), H63D was more prevalent in hepatocellular carcinoma patients than in controls (38.5 vs. 27.9%, respectively). The association was stronger when considering only male patients with hepatocellular carcinoma (47.1 vs. 23.6, p=0.001). Allele frequencies of S and Z in controls were 0.45% (95% CI=0.2-1.07) and 0.22% (95% CI=0.2-0.6), respectively, and 1 for S and 0% for Z in HCC. No significant difference was found between cases and controls. CONCLUSIONS We provide a novel appraisal of HFE and SERPINA1 mutations prevalence in the Moroccan population. Results are consistent with the worldwide spread of the H63D and S mutation and the north European restriction of the C282Y and Z. Our results show that H63D carriage is increased among hepatocellular carcinoma patients, suggesting that it may confer an increased susceptibility to hepatocellular carcinoma even in a heterozygous state. On the contrary, HFE C282Y and SERPINA1 mutations do not contribute to hepatocellular carcinoma development.

The 752delG26 mutation in the RFXANK gene associated with major histocompatibility complex class II deficiency: evidence for a founder effect in the Moroccan population

Major histocompatibility complex class II plays a key role in the immune response, by presenting processed antigens to CD4+ lymphocytes. Major histocompatibility complex class II expression is controlled at the transcriptional level by at least four trans-acting genes: CIITA, RFXANK, RFX5 and RFXAP. Defects in these regulatory genes cause MHC class II immunodeficiency, which is frequent in North Africa. The aim of this study was to describe the immunological and molecular characteristics of ten unrelated Moroccan patients with MHC class II deficiency. Immunological examinations revealed a lack of expression of MHC class II molecules at the surface of peripheral blood mononuclear cells, low CD4+ T lymphocyte counts and variable serum immunoglobulin (IgG, IgM and IgA) levels. In addition, no MHC class II (HLA DR) expression was observed on lymphoblasts. The molecular analysis identified the same homozygous 752delG26 mutation in the RFXANK genes of all patients. This finding confirms the association between the high frequency of the combined immunodeficiency and the defect in MHC class II expression and provides strong evidence for a founder effect of the 752delG26 mutation in the North African population. These findings should facilitate the establishment of molecular diagnosis and improve genetic counselling for affected Moroccan families.

Characterization and antibiotic susceptibility of Listeria monocytogenes isolated from poultry and red meat in Morocco.

This study was carried out on 426 samples of raw meats collected from butcheries and supermarkets in Casablanca, Morocco. The samples were examined for the occurrence of Listeria species. Strains of Listeria monocytogenes were characterized by several biochemical tests and confirmed by polymerase chain reaction (PCR). β-hemolytic cultures and nonhemolytic isolates were tested for biochemical properties with the Listeria API test. Among the 43 Listeria species isolates; we identified 10 strains for L. monocytogenes (23.3%), 31 strains for L. innocua (72.1%) and 2 strains for L. welshimeri (4.6%). Strains of L. monocytogenes were separated by multiplex PCR; two serogroups IIb and IVb were thus differentiated. Antibiotic susceptibility of L. monocytogenes to 21 antibiotics was determined by the disk diffusion method. All isolates were susceptible to a wide range of the tested antibiotics with the exception of nalidixic acid, colistine and cephalosporins second and third generation for which they were all resistant.