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Showing 4 results for Siadat
Seyed Davar Siadat , Hoda Shirdast , Mohammadreza Aghasadeghi, Darioush Norouzian, Seyed Mohammad Atyabi , Seyed Mahdi Sadat , Sanaz Soleymaniyeh , Ali Sharifat , Arfa Moshiri ,
Volume 10, Issue 3 (autumn 2010)
Background & Objectives: Lipopolysaccharide (LPS) is the main antigenic structure expressed on the surface of smooth strains of Brucella. It has been shown that Outer membrane vesicle (OMV) of Neisseria meningitidis efficiently promote IgG and IgM response against the administrated antigen as an adjuvant. The aim of this study is to evaluate the effect of LPS-OMV noncovalent complex in producing of T helper 1 cytokine (IFN-γ) and T helper 2 cytokines (IL-4 and IL-10) in mice.
Methods: LPS extracted by an optimized method based on hot phenol-water extraction. Groups of six BALB/c mice were injected subcutaneously with LPS alone, LPS with Freund adjuvant and LPS-OMV complex on 0, 14 and 28 days. Levels of IFN-γ, IL-4 and IL-10 were evaluated in spleen cell suspension supernatant by ELISA.
Result: Immunization with B. abortus LPS significantly induced high level of IFN-γ in comparison to the other groups immunized with LPS-OMV and LPS+ adjuvant (p<0.05). In contrast, lower levels of IL-4 and IL-10 were elicited by LPS in the rest groups. Immunization with the non-covalent complex of B. abortus LPS-N. meningitidis serogroup B OMV caused a significant increase of IL-4 and IL-10 compared with the mice immunized with B. abortus LPS (p<0.05), while the titer of IFN-γ is still significantly higher than IL-4 and IL-10 (p<0.05).
Conclusion: The raise of IFN-γ following the immunization with all of the compounds (LPS, LPS-OMV non-covalent complex and LPS+adjuvant) indicates the activation of Th1 population that would be correlated to the clearance of the organism due to the amplification of anti-microbial activity of Polymorphonuclear cells. Low levels of IL-4 and IL-10 following the immunization with all compounds would be a sign of Th1 responses dominancy or inhibition of Th2 population proliferation and activity. Such a cytokine pattern would be a sign of the efficiency of brucellosis subunit vaccine because Th2 responses basically have no role in the immune responses against Brucella and may lead to the persistence of intracellular infection.
Manoochehr Barak , Setareh Mamishi , Seiyed Ahmad Siadati , Peyman Salamati , Ghamartaj Khotaii, Mehrdad Mirzarahimi ,
Volume 11, Issue 2 (summer 2011)
Background & objectives: Nosocomial infections increase patient’s mortality and are considered as a health problem. The aim of this study was to assess the risk factors for nosocomial infections and antimicrobial resistance pattern of isolated bacteria in NICU and PICU, in Bahrami and Children’s Medical Center hospitals, Tehran .
Methods: In a prospective cross-sectional study from October 2008 to September 2009, risk factors and etiology of nosocomial infections were evaluated in all patients who showed infectious signs upon 48h admission. Infectious agents were diagnosed by the standard microbiological tests and antibiotic sensitivity of isolates was determined using dick diffusion method. The data for location of the hospital, admission history, presence of immunodeficiency, fever and using venous and urine catheters, suction, venous injection as well as cerebral shunt and surgery have been collected by a questionnaire and analyzed, statistically .
Results: About 9.3% (70 individuals) of cases encountered with nosocomial infections. From whom, 24.3% were infected by Pseudomonas aeroginosa and 18.6% and 3.14% by Klebsiella pneumonia and Enterobacter spp, respectively. The location of the hospital, using of suction and surgery were the most common risk factors related to nosocomial infections (p<0.05).
Conclusion: Our findings showed that the hospital location, suction and surgery were the most common risk factors and Pseudomonas aeroginosa, Klebsiella pneumonia and Enterobacter spp were the common infectious threats. So, we need to design the special program to improve nosocomial infection control in hospitals .
Rezvan Zabihollahi , Maryam Nourmohammadi , Azar Farhang Esfahani, Rohollah Vahabpour, Seiyed Mahdi Sadat , Mohammad Reza Aghasadeghi , Mansour Salehi , Seiyed Davar Siadat ,
Volume 12, Issue 1 (spring 2012)
Background & Objectives : Several studies have been conducted to explore anti-HIV drugs. Discovery and study of novel anti-HIV-1 compounds need live viruses and has serious biosafety concerns. In this research we reported a novel and safe system for assaying the cytopathic effects of HIV by using single cycle replicable (SCR) HIV-1 virions.
Methods: To produce the SCR HIV-1 virions, pMD2G, pmzNL4-3 and pSPAX2 plasmids were co-transfected into HEK293T cells. Different amount of SCR virions were used to infect target cells (MT-2). Within the infected cells, the number of formed syncytia was counted under the light microscopy. The lethal effects of the SCR HIV virions were measured using XTT proliferation assay.
Results: Formation of syncytia among SCR HIV infected cells was detectable 24 hours after infection. Highest amount of syncytia was seen 72 hours after infection. Increase in the amount of virions caused increasing of syncytia and the cytopathic effects of SCR HIV-1. Infection with more than 1600ng P24 SCR HIV decreased the syncytium formation and viability of all cells. The calculated IC50 (50 percent inhibitory capacity) for nevirapine and BMS806 using this method was 50nM and 30nM, respectively.
Conclusion: SCR HIV-1 virions are replicable only for one cycle. Using these virions can improve the safety of HIV researches. Herein, we optimized the assaying of HIV induced cytopathic effects by using SCR HIV-1 (NL4-3) virions. The accuracy of this method was accepted by quantifying the anti-HIV-1 effects of nevirapine and BMS806 by (SCR) HIV-1 virions.
Farshad Nojoomi, Ashraf Mohabati Mobarez, Ali Hatef Salmanian, Seiyed Davar Siadat, Nima Khoramabadi, Haniyeh Aghababa,
Volume 12, Issue 4 (winter 2012)
Background & Objectives: Haemophilus influenzae is a Gram-negative bacterium that is part of the normal nasopharyngeal flora of most humans. H. influenzae strains were defined in two categories: encapsulated (typeable) and non-capsulated (nontypeable) strains. Outer membrane protein P6 is a highly conserved and stable protein in the outer membrane of both encapsulated and non-capsulated strains of H. influenzae. As an immunogen, P6 protein is a potential candidate vaccine against H. influenzae strains. The aim of this study was to produce recombinant protein P6 as a carrier protein for production of conjugate vaccines.
Methods: The sequence (324 bp) coding P647-153 protein of H. influenzae was successfully cloned in pJET1.2 and subsequently in pET28a (+). Expression of the recombinant protein was induced with 1mM IPTG. Recombinant P647-153 was purified through dissolving inclusions in 8M urea buffer, absorbing to Ni-NTA resins, washing by buffers with decreasing urea concentration and finally eluted in Imidazole solution. Imidazole was removed by dialysis against PBS (pH 7.4). The recombinant p6 47-153 was confirmed by western blot analysis using rabbit anti H. influenzae polyclonal antiserum.
Results: The recombinant P647-153 was successfully expressed in E. coli BL21 (DE3) and purified (4 mg /lit of broth culture). The immunoblotting showed that recombinant P647-153 conserved its native antigenic structure.
Conclusion: Western blot results, along with that of sequencing, confirmed accurate production of recombinant P647-153 and partially retention of its conformational epitopes.