Muzamil abdel hamid

Publications (12) View all

• Article: Characterization of lipid profiles in coronary heart disease patients in Sudan

  Hassan Hussein Musa, Etayeb Mohamed Ahmed Tyrab, Muzamil Mahdi Abdel Hamid, Elbagire Abdel Rahman Elbashir, Lemya Mohammed Yahia, Nihad Mohammed Salih
  Indian heart journal 03/2013;
• Source

  Available from: Edmond Joseph Remarque

  Article: Malaria infection by sporozoite challenge induces high functional antibody titres against blood stage antigens after a DNA prime, poxvirus boost vaccination strategy in Rhesus macaques.

  Muzamil Mahdi Abdel Hamid, Edmond J Remarque, Ibrahim M El Hassan, Ayman A Hussain, David L Narum, Alan W Thomas, Clemens H M Kocken, Walter R Weiss, Bart W Faber
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  ABSTRACT: A DNA prime, poxvirus (COPAK) boost vaccination regime with four antigens, i.e. a combination of two Plasmodium knowlesi sporozoite (csp/ssp2) and two blood stage (ama1/msp142) genes, leads to self-limited parasitaemia in 60% of rhesus monkeys and survival from an otherwise lethal infection with P. knowlesi. In the present study, the role of the blood stage antigens in protection was studied in depth, focusing on antibody formation against the blood stage antigens and the functionality thereof. Rhesus macaques were immunized with the four-component vaccine and subsequently challenged i.v. with 100 P. knowlesi sporozoites. During immunization and challenge, antibody titres against the two blood stage antigens were determined, as well as the in vitro growth inhibition capacity of those antibodies. Antigen reversal experiments were performed to determine the relative contribution of antibodies against each of the two blood stage antigens to the inhibition. After vaccination, PkAMA1 and PkMSP1₁₉ antibody titres in vaccinated animals were low, which was reflected in low levels of inhibition by these antibodies as determined by in vitro inhibition assays. Interestingly, after sporozoite challenge antibody titres against blood stage antigens were boosted over 30-fold in both protected and not protected animals. The in vitro inhibition levels increased to high levels (median inhibitions of 59% and 56% at 6 mg/mL total IgG, respectively). As growth inhibition levels were not significantly different between protected and not protected animals, the ability to control infection appeared cannot be explained by GIA levels. Judged by in vitro antigen reversal growth inhibition assays, over 85% of the inhibitory activity of these antibodies was directed against PkAMA1. This is the first report that demonstrates that a DNA prime/poxvirus boost vaccination regimen induces low levels of malaria parasite growth inhibitory antibodies, which are boosted to high levels upon challenge. No association could, however, be established between the levels of inhibitory capacity in vitro and protection, either after vaccination or after challenge.
  Malaria Journal 02/2011; 10(1):29. · 3.19 Impact Factor
• Source

  Available from: Edmond Joseph Remarque

  Article: Vaccination with Plasmodium knowlesi AMA1 formulated in the novel adjuvant co-vaccine HT™ protects against blood-stage challenge in rhesus macaques.

  Muzamil Mahdi Abdel Hamid, Edmond J Remarque, Leonie M van Duivenvoorde, Nicole van der Werff, Vanessa Walraven, Bart W Faber, Clemens H M Kocken, Alan W Thomas
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  ABSTRACT: Plasmodium falciparum apical membrane antigen 1 (PfAMA1) is a leading blood stage vaccine candidate. Plasmodium knowlesi AMA1 (PkAMA1) was produced and purified using similar methodology as for clinical grade PfAMA1 yielding a pure, conformational intact protein. Combined with the adjuvant CoVaccine HT™, PkAMA1 was found to be highly immunogenic in rabbits and the efficacy of the PkAMA1 was subsequently tested in a rhesus macaque blood-stage challenge model. Six rhesus monkeys were vaccinated with PkAMA1 and a control group of 6 were vaccinated with PfAMA1. A total of 50 µg AMA1 was administered intramuscularly three times at 4 week intervals. One of six rhesus monkeys vaccinated with PkAMA1 was able to control parasitaemia, upon blood stage challenge with P. knowlesi H-strain. Four out of the remaining five showed a delay in parasite onset that correlated with functional antibody titres. In the PfAMA1 vaccinated control group, five out of six animals had to be treated with antimalarials 8 days after challenge; one animal did not become patent during the challenge period. Following a rest period, animals were boosted and challenged again. Four of the six rhesus monkeys vaccinated with PkAMA1 were able to control the parasitaemia, one had a delayed onset of parasitaemia and one animal was not protected, while all control animals required treatment. To confirm that the control of parasitaemia was AMA1-related, animals were allowed to recover, boosted and re-challenged with P. knowlesi Nuri strain. All control animals had to be treated with antimalarials by day 8, while five out of six PkAMA1 vaccinated animals were able to control parasitaemia. This study shows that: i) Yeast-expressed PkAMA1 can protect against blood stage challenge; ii) Functional antibody levels as measured by GIA correlated inversely with the day of onset and iii) GIA IC(50) values correlated with estimated in vivo growth rates.
  PLoS ONE 01/2011; 6(5):e20547. · 4.09 Impact Factor
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  Available from: Muzamil abdel hamid

  Article: Uncommon clinical presentations of cutaneous leishmaniasis in Sudan.

  E M Elamin, S Guerbouj, A M Musa, I Guizani, E A G Khalil, M M Mukhtar, A M Y Elkadaro, H S Mohamed, M E Ibrahim, M M Abdel Hamid, M El Azhari, A M El Hassan
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  ABSTRACT: Cutaneous leishmaniasis in Sudan is caused by Leishmania major zymodeme LON1. Self-healing usually occurs within 1 year but occasionally its duration is prolonged and treatment is required. The clinical forms are ulcers, nodules and noduloulcerative lesions. Here we describe seven patients with uncommon lesions that were difficult to recognize as Leishmania infections. These included mycetoma-like lesions, lesions that resembled L. tropica infection and others. One HIV/AIDS patient had Kaposi's sarcoma with Leishmania parasites in the Kaposi lesions. Most of these uncommon clinical forms were difficult to treat. The diagnosis depended on a high degree of suspicion and the demonstration of parasites in smears or culture. PCR was used to characterize parasites from the patients described here. Leishmania major was found by kDNA PCR in all patients, except one, who had a leishmanioma due to L. donovani. In three patients, including one with a L. tropica like-lesion, the parasites were confirmed as L. major by gp63 PCR-RFLP.
  Transactions of the Royal Society of Tropical Medicine and Hygiene 12/2005; 99(11):803-8. · 2.16 Impact Factor
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  Available from: Muzamil abdel hamid

  Article: Evolutionary conservation of RNA editing in the genus Leishmania.

  Muntaser E Ibrahim, Muzamil A Mahdi, Rihab E Bereir, Rania S Giha, Christina Wasunna
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  ABSTRACT: RNA editing in kinetoplastids is the process by which vital genetic informations are restored through insertion and deletion of uridine residues in coding sequences, particularly those of the mitochondrial pre-mRNA. Mammalian infecting Leishmania were not analyzed before for the presence of RNA editing to establish whether the mechanism is still in use in higher lineages of the genus. The Cytochrome Oxidase gene of Leishmania tarentolae is known to be edited at its 3' end with gRNA encoded in the region immediately downstream. We sequenced DNA and cDNA of the COII gene of Leishmania donovani and compared those to Leishmania tarentolae sequences from the database. The results reveal an insertion of uridines in a manner identical to L. tarentolae, leading to restoration of the amino acid sequence with relative conservation of the gRNA region. We conclude that RNA editing as a posttranscriptional mechanism is still conserved within higher evolutionary lineages of the genus Leishmania.
  Infection Genetics and Evolution 06/2008; 8(3):378-80. · 3.13 Impact Factor