An-Najah National University


My Research Interests: 1) Genetic Diseases 2)Drug development against parasitic diseases based on molecular and biochemical techniques

  • Wednesday, January 19, 2011
  • Properties and characterization of γ-glutamyl transpeptidase from Onchocerca volvulus
  • Published at:ANU-MHSJ
  • γ-glutamyl transpeptidase (GGT) from Onchocerca volvulus is involved in the oxidative stress. The enzyme catalyzes the breakdown of glutathione (GSH) and thus provide the parasite with cysteine for the synthesis of GSH and other amnio acids. The enzyme, which was highly purified from Onchocerca volvulus, is found to be membrane-bound with a specific activity of 100 U mg-1 and a molecular mass of 68 KDa.  The apparent Km-values for the γ-glutamyl donor  L-glutamic acid γ-(4-nitroanilide) is 0.023 ± 0.013 mM. The data presented in this study showed that various amino acids and dipeptides served for the γ-glutamyl moieties of the enzyme reaction products and showed Km values in the mM range. Acivicin was an irreversible inhibitor of the enzyme with a pseudo-first-order kinetics (kmax) of 0.34 ± 0.004 min−1 and KI = 0.59 ± 0.04 mM. These finding indicate the physiological role of the GGT of this parasite nematode in the catabolism of GSH. Further studie
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  • Saturday, October 2, 2010
  • Association between Factor V Leiden Mutation and Poor Pregnancy Outcomes among Palestinian Women
  • Published at:Thromobosis Research
  • Pregnancy is a hypercoagulable state with increased tendency for thrombus formation, a condition that is increased when combined with acquired or inherited risk factors that lead to thrombophilia. Among the inherited risk factors is Factor V Leiden mutation, an autosomal dominant trait with reduced penetrance. The mutation seems to be associated with different poor pregnancy outcomes including recurrent miscarriages. In the present study, we performed a case-control study to investigate the association between the Leiden mutation and poor pregnancy outcome among the Palestinian population in the West bank region of Palestine.  The study included 145 subjects with recurrent miscarriages and 205 matched control subjects with successful pregnancies who experienced normal delivery and no apparent complications. Leiden mutation was detected in 41 of the145 study subjects (28.2%), and in 24 of the 205 control subjects (11.7%). Subjects homozygous for the mutant allele were identified only among the test and no
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  • Saturday, October 2, 2010
  • Prevalence of intestinal parasites among school children in northern districts of West Bank- Palestine
  • Published at:Tropical Medicine and International Hygiene
  • Parasite infections are amongst the most common infections worldwide. The objectives of this study were to assess the prevalence of intestinal parasite infections in northern districts of West Bank, Palestine and to determine associated sociodemographic factors. The study involved a random sample of 735 school children of mean age 9.5 years old from rural and urban areas. Fecal samples were collected from participants alongside a questionnaire about their demographic and hygiene habits. Microscopy and PCR methods were performed to screen for protozoan and helminths parasites. The overall prevalence was 22.2%. The rates of infections with ameba, Giardia intestinalis, Entrobius vermicularis and Ascaris lumbricoides were 9.7%, 4.1%, 1.6% and 3.8%, respectively. Real-time PCR was performed to differentiate between Entamoeba histolytica and E. dispar. Results showed that 14% of samples positive with microscopy for ameba were positive for E. histolytica. There was no significant association between sex and rates of
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  • Thursday, September 16, 2010
  • Cryptosporidium parvum causes gastroenteritis epidemics in the Nablus region of Palestine
  • Published at:Tropical Medicine and international Hygiene
  • A total of 30 fecal samples collected from individuals admitted to a local hospital in Nablus city in Palestine with gastroenteritis symptoms, plus 5 fecal samples from healthy individuals living in the same area were screened for the presence of Cryptosporidium spp. by microscopic analysis using malachite green negative staining. Molecular techniques were used to confirm the microscopic identification. Of these, all the 30 samples from individuals with gastroenteritis symptoms were positive by both techniques. No other parasites were found in the fecal material of patients or healthy individuals. To explore the source of the outbreak, water was collected from various reservoirs and springs which supply the city with drinking water. Al-Qaryoon water spring was also found to be contaminated with Cryptosporidium using both microscopic and molecular analysis. No other water resources was found to be contaminated. Genotyping analysis of Cryptosporidium oocysts using PCR-RFLP technique identified the parasite as C
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  • Thursday, February 26, 2009
  • Ayman S. HUSSEIN, Sami K. ABDEL-HAFEZ and Ahmad M. KHALIL. Isolation and characterization of excretory/secretory products from in vitro developmental stages of Echinococcus granulosus. Jpn J. Parasitol., (1994) vol. 43. No. 2, 82-89.
  • Published at:Not Found
  • Excretory/secretory (E/S) products of Echinococcus granulosus were prepared from presentation stages (PS1, PS2, PS3 and PS4) and one segmented (S5) stage which corresponded to 1-, 5-, 12-, 26- and 43-day old in vitro cultured parasites, respectively. Cultures were initiated from protoscolices collected from hydatid cysts of indigenous Jordanian ewes. The E/S products were characterized using SDS-PAGE with silver, Comassie-blue and PAS staining as well as immunobltting with sera from hydatid patients and immunized mice. Younger cultured stages yielded small quantities of E/S materials, compared to the banding (PS4) and segmented (S5) stages. The E/S products from various stages of cultured parasites were heterogeneous and contained 15-28 protein bands and 3-6-PAS+ bands. A total of 13 protein bands were shared among the E/S products of various cultured stages. 11 of which were also shared with crude sheep hydatid fluid (CSHF), tegumental and somatic antigens. The E/S products of PS1-S5 stages and CSHF shared 3
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Ayman Hussein, Associate Professor
Biochemistry of Parasites
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