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Search Results: 1 - 10 of 2906 matches for " Hossein Nahrevanian "
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Immune effector mechanisms of the nitric oxide pathway in malaria: cytotoxicity versus cytoprotection
Nahrevanian, Hossein;
Brazilian Journal of Infectious Diseases , 2006, DOI: 10.1590/S1413-86702006000400014
Abstract: nitric oxide (no) is thought to be an important mediator and critical signaling molecule for malaria immunopathology; it is also a target for therapy and for vaccine. inducible nitric oxide synthase (inos) is synthesized by a number of cell types under inflammatory conditions. the most relevant known triggers for its expression are endotoxins and cytokines. to date, there have been conflicting reports concerning the clinical significance of no in malaria. some researchers have proposed that no contributes to the development of severe and complicated malaria, while others have argued that no has a protective role. infection with parasites resistant to the microbicidal action of no may result in high levels of no being generated, which could then damage the host, instead of controlling parasitemia. consequently, the host-parasite interaction is a determining factor for whether the parasite is capable of stimulating no production; the role of no in resistance to malaria appears to be strain specific. it is known that no and/or its related molecules are involved in malaria, but their involvement is not independent of other immune events. no is an important, but possibly not an essential contributor to the control of acute-phase malaria infection. the protective immune responses against malaria parasite are multifactorial; however, they necessarily involve final effector molecules, including no, inos and rni.
Involvement of nitric oxide and its up/down stream molecules in the immunity against parasitic infections
Nahrevanian, Hossein;
Brazilian Journal of Infectious Diseases , 2009, DOI: 10.1590/S1413-86702009000600010
Abstract: nitric oxide (no) is a potent mediator with diverse roles in regulating cellular functions and signaling pathways. the no synthase (nos) enzyme family consists of three major isoforms, which convey variety of messages between cells, including signals for vasorelaxation, neurotransmission and cytotoxicity. this family of enzymes are generally classified as neuronal nos (nnos), endothelial nos (enos) and inducible nos (inos). increased levels of no are induced from inos during infection; while enos and nnos may be produced at the baseline in normal conditions. an association of some key cytokines appears to be essential for nos gene regulation in the immunity of infections. accumulating evidence indicates that parasitic diseases are commonly associated with elevated production of no. no plays a role in the immunoregulation and it is implicated in the host non-specific defence in a variety of infections. nevertheless, the functional role of no and nos isoforms in the immune responses of host against the majority of parasites is still highly controversial. in the present review, the role of parasitic infections will be discussed in the controversy related to the no production and inos gene expression in different parasites and a variety of experimental models.
Pathogenicity Variations of Susceptibility and Resistance to Leishmania major MRHO/IR/75/ER Strain in BALB/c and C57BL/6 mice
Marzieh Amini,Hossein Nahrevanian,Mahin Farahmand
Iranian Journal of Parasitology , 2008,
Abstract: Background: To compare the pathogenicity differences in two susceptible Balb/c and resistant C57bl/6 mice infected with Leishmania major MRHO/IR/75/ER as a prevalent strain of zoonotic cutaneous leishmaniasis in Iran. Methods: Mice were assigned into four groups as control and infected BALB/c and C57BL/6 mice. Experimental leishma-niasis was initiated by (s. c) injection of the 2×106 L. major promastigotes into the basal tail of infected groups. The devel-opment of lesions was determined weekly by measuring the two diameters. After 10 weeks, all mice were killed humanly, target tissues including lymph node, spleen and liver from each mouse were removed, weighted, and their impression smears were prepared. Results: Proliferation of amastigotes inside macrophages, pathogenicity signs in two susceptible, resistant hosts was varied, and these variations were depended on mice strain. Conclusion: Host immunity may modify clinical signs and could affect the proliferation of amastigotes inside macro-phages, the size of lesions, the survival rates, the degree of hepatomegaly and splenomegaly and the percentage of amasti-gotes in lesion, liver, spleen, lymph node and brain smears.
Antimalarial Effects of Iranian Flora Artemisia sieberi on Plasmodium berghei In Vivo in Mice and Phytochemistry Analysis of Its Herbal Extracts
Hossein Nahrevanian,Bayram Sheykhkanlooye Milan,Masoud Kazemi,Reza Hajhosseini,Soudeh Soleymani Mashhadi,Shahab Nahrevanian
Malaria Research and Treatment , 2012, DOI: 10.1155/2012/727032
Abstract: The aim of this study is pharmacochemistry of Iranian flora Artemisia sieberi and its antimalarial effects on Plasmodium berghei in vivo. This is the first application of A. sieberi for treatment of murine malaria. A. sieberi were collected at flowering stage from the Khorassan and Semnan provinces of Iran; the aerial parts were air-dried at room temperature and then powdered. The powder was macerated in methanol, filtered with Bokhner hopper and solvent was separated in rotary evaporator. Total herbal extract was subsequently processed for ether and chloroform extracts preparation. The toxicity of herbal extract was assessed on naive NMRI mice with high, average and low doses; then pathophysiological signs were assessed. Finally, the antimalarial efficacy was investigated on two groups of Plasmodium berghei infected mice. Percentage of parasitaemia and pathophysiology were also evaluated. The results of this assessment showed no toxicity even by high concentration of herbal extract. A significant reduction in percentage of parasitaemia was observed; no alterations of hepatosplenomegaly and body weight were indicated in study group. A. sieberi extracts showed antimalarial effects against murine malaria with some efficacies on reducing pathophysiology. However, there is requirement to find the major component of this herbal extract by further studies. 1. Introduction Malaria is one of the most serious and widespread diseases encountered by human. It is an infectious disease caused by the parasite Plasmodia (P.) transmitted by the female anopheles. Four identified species of this parasite exist, which cause different types of human malaria [1]. Although all the four species of malaria parasites can infect humans and cause illness, only P. falciparum is known to be potentially life threatening and some of infected persons die, usually because of delayed treatment [2]; however, annual incidence of clinically new cases and mortality rates are decreasing [3–6]. As malaria vaccines remain problematic, chemotherapy still is the most important weapon in the fight against the disease [7]. The antimalarial drugs including chloroquine, quinine, mefloquine, pyrimethamine, and artemisinin are currently used in malaria treatment. Part of the reason for the failure to control malaria is the spread of resistance to first-line antimalarial drugs, cross-resistance between the limited number of drug families available, and some multidrug resistance [8]. Resistance has emerged to all classes of antimalarial drugs except artemisinin, an endoperoxide antimalarial drug derived
Patterns of co-association of C-reactive protein and nitric oxide in malaria in endemic areas of Iran
Nahrevanian, Hossein;Gholizadeh, Jafar;Farahmand, Mahin;Assmar, Mehdi;
Memórias do Instituto Oswaldo Cruz , 2008, DOI: 10.1590/S0074-02762008000100006
Abstract: in addition to numerous immune factors, c-reactive protein (crp) and nitric oxide (no) are believed to be molecules of malaria immunopathology. the objective of this study was to detect crp and no inductions by agglutination latex test and griess microassay respectively in both control and malaria groups from endemic areas of iran, including southeastern (se) (sistan & balouchestan, hormozgan, kerman) and northwestern (nw) provinces (ardabil). the results indicated that crp and no are produced in all malaria endemic areas of iran. in addition, more crp and no positive cases were observed amongst malaria patients in comparison with those in control group. a variable co-association of crp/no production were detected between control and malaria groups, which depended upon the malaria endemic areas and the type of plasmodia infection. the percentage of crp/no positive cases was observed to be lower in nw compare to se region, which may be due to the different type of plasmodium in the nw (plasmodium vivax) with se area (p. vivax, plasmodium falciparum, mixed infection). the fluctuations in crp/no induction may be consistent with genetic background of patients. although, crp/no may play important role in malaria, their actual function and interaction in clinical forms of disease remains unclear.
Immuno-Biochemical Alterations in Leishmania major Infected Balb/c Mice after Immunization with Killed Leishmania Vaccine and BCG as Adjuvant
Sara Nemati,Seyedeh Parisa Jafary,Hossein Nahrevanian,Mahin Farahmand
Current Research Journal of Biological Sciences , 2012,
Abstract: BCG is an immune modulatory that inducing humoral and cellular immune responses during a number of infections including cutaneous leishmaniasis. Killed Leishmania Vaccine (KLV) has been applied for its immunogenicity in hosts. This study was carried out between 2010 and 2011 at the Department of Parasitology, Pasteur Institute of Iran. In the present study, alterations of Nitric Oxide (NO) levels, total content of essential trace elements (Cu, Zn) and liver enzymes (SGOT, SGPT) were investigated in Balb/c mice infected with Leishmania major. Results showed that BCG induced NO in liver; Zn increased in KLV/BCG and KLV test groups and Cu decreased in KLV test group, but increased in BCG test group. Moreover to decreasing SGOT level in KLV/BCG test group, SGPT decreased in BCG test group. Our findings showed that serum trace element concentrations were altered in CL infection, probably in accordance with host defense mechanisms. It is indicated that application of KLV/BCG as a combined vaccine/adjuvant could be indicated as a potent inducer of immuno-biochemical characters during infection with Leishmaniasis. In conclusion, some dependency is observed between KLV/BCG and NO levels, Cu, Zn concentrations and SGOT, SGPT production. The mechanism of KLV/BCG action may be associated more on BCG rather than KLV.
The Effects of Cholestasis and Cirrhosis on Gastric Acid and Pepsin Secretions in Rat: Involvement of Nitric Oxide
Fatemeh Nabavizadeh,Rohallah Moloudi,Ahmad Reza Dehpour,Hossein Nahrevanian
Iranian Journal of Basic Medical Sciences , 2010,
Abstract: Objective(s)The liver has major role in the organism homeostasis, interactions with other systems, synthesis and metabolism of bile production, drug detoxification and hormone inactivation. Cholestasis can be defined as an impairment of the bile flow which can lead to hepatocytes necrosis and finally cirrhosis. Some studies reported a gastric acid secretion reduction in cirrhotic subjects, while others reported normal production gastric acid secretion. Our aim was to evaluate the effects of cholestasis and cirrhosis on gastric acid and pepsin secretions and its possible mechanism in rat.Materials and MethodsMale Wistar rats were randomly divided into five groups (n= 8): control, cholestasis, sham cholestasis, cirrhosis and sham cirrhosis. Laparatomy was done under general anesthesia and then bile duct ligation (BDL) was performed. After 2 and 4 weeks in cholestasis and cirrhosis groups respectively, gastric content was collected by wash-out technique. Basal and stimulated acid and pepsin secretions were measured by using titration and the Anson method respectively in all groups. In order to measure stimulated acid and pepsin secretions, pentagastrin (25 μg/kg, i.p.) was used. Nitric Oxide (NO) metabolites of gastric tissue were determined by Griess microassy method.ResultsAcid and pepsin secretions were significantly reduced in cholestatic and cirrhotic rats in comparison with control and sham groups (P< 0.01). NO metabolite of gastric tissue was significantly increased in cholestatic and cirrhotic rats (P< 0.01).ConclusionReducing of gastric acid and pepsin output in cholestatic and cirrhotic rats may be due to increasing in NO content of gastric tissue.
Seroprevalence of Toxoplasma gondii Antibodies in Dairy Cows in Kerman Province, South East Iran
Hassan Sanati,Saeid Reza Nourollahi Fard,Hossein Nahrevanian,Mohammad Khalili
Current Research Journal of Biological Sciences , 2012,
Abstract: Toxoplasma gondii is a ubiquitous protozoan that causes the most common parasitic infection in humans. Since the disease is of economic importance with regard to animal productions, it is necessary to investigate the prevalence of T. gondii infection in meat producing animals especially cattle which constitutes the main source of meat for local consumption. The aim of this study was to investigate the seroprevalence of toxoplasmosis in dairy cows of Kerman region (southeastern Iran) using Modified Agglutination Test (MAT). The sera of 300 dairy cows have been investigated for antibodies against Toxoplasma gondii. The results indicated two hundred and fourteen samples (71.3%) were seropositive and 86 samples (28.7%) were seronegative. Out of the 300 cattle (39 male, 261 female) screened, 87% of male and 13% of female cattle were contaminated with toxoplasmosis. Since cows are one of the most important meat sources in Iran, there is a high risk of contamination through meat from this host due to their susceptibility to infection. Further studies are required for more data on the prevalence of T. gondii in other meat producing animals to apply effective control strategies against toxoplasmosis.
An overview of a diagnostic and epidemiologic reappraisal of cutaneous leishmaniasis in Iran
Farahmand, Mahin;Nahrevanian, Hossein;Shirazi, Hasti Atashi;Naeimi, Sabah;Farzanehnejad, Zahra;
Brazilian Journal of Infectious Diseases , 2011, DOI: 10.1590/S1413-86702011000100004
Abstract: cutaneous leishmaniasis (cl) is a widespread tropical infection which has a high incidence rate in iran. leishmania tropica, the causative agent of anthroponotic cutaneous leishmaniasis (acl), and leishmania major, which causes zoonotic cutaneous leishmaniasis (zcl), are endemic in various parts of iran with a high incidence rate. the aim of this study was to evaluate the reappraisal of the diagnosis and epidemiology of cl in iran, by different clinical, parasitological and molecular assays among patients suspected of cl referred to the department of parasitology, at the pasteur institute of iran during 2006-2009. two hundred samples from patients with ulcerative skin lesions were collected, clinical analyses were applied, data questionnaire was completed and samples were examined for cl by using both direct microscopic and culture methods. moreover, pcr assay was applied for detection of leishmania species in cl isolates resulting from parasitological assay. clinical observation revealed that the majority (58%) of lesions was single; double lesions were observed in 22% of patients, and only 20% of cl had multiple lesions. out of 200 patients, leishman body was observed in 77 samples (38.5%) by direct smear and 40% by cultivation assay. most patients (21.3%) had a travel history to the isfahan province, one of the most important endemic areas of cl located in center of iran. pcr assay by kdna indicated 32 and 18 out of 50 isolates respectively had similar patterns with standard l. major and l. tropica. in conclusion, clinical manifestations and an appropriate diagnostic assay with a parallel molecular characterization of cl may lead to a screening evaluation of disease, prognosis, treatment and control strategies.
Biochemical association between essential trace elements and susceptibility to Leishmania major in BALB/c and C57BL/6 mice
Amini, Marzyeh;Nahrevanian, Hossein;Khatami, Shohreh;Farahmand, Mahin;Mirkhani, Fatemeh;Javadian, Seifoddin;
Brazilian Journal of Infectious Diseases , 2009, DOI: 10.1590/S1413-86702009000200002
Abstract: several enzymes that contribute to immune system responses require zinc and copper as trace elements for their activity. we examined zinc and copper levels in two susceptible balb/c mouse lines and resistant c57bl/6 mice infected with leishmania major mrho/ir/75/er, a prevalent strain that causes cutaneous leishmaniasis in iran. serum zn and cu were determined by flame atomic absorption spectrophotometry. higher cu levels were found in infected c57bl/6 mice and higher zn levels were found in infected balb/c mice. also, cu/zn ratios were increased in both the balb/c and the c57bl/6 mice. we conclude that concentrations of essential trace elements vary during cutaneous leishmaniasis infection and that this variation is associated with susceptibility/resistance to leishmania major in balb/c and c57bl/6 mice. we detected zn deficiency in the plasma of infected balb/c mice; possibly, therapeutic administration of zn would be useful for treating this form of leishmaniasis. increases in cu level might increase resistance to leishmaniasis. based on our findings, the cu/zn ratio could be a useful marker for the pathophysiology of leishmaniasis.
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