Sequence diversity in tRNA gene locus A-L among Iranian isolates of entamoeba dispar

A number of methods for detecting diversity in Entamoeba have been described over the years. In the present study the genetic polymorphism of noncoding locus A-L was analyzed using PCR and sequencing in order to clarify the genotypic differences among E. dispar isolates. A total of 28 E. dispar from patients with gastrointestinal symptoms were determined and the genomic DNA was extracted directly from stool. For genotype analysis; Locus A-L was amplified by PCR and PCR products were sequenced .The sequences obtained were edited manually and aligned using Gene Runner software. With sequencing of PCR products a reliable genetic diversity in size, number and position of the repeat units were observed among the Iranian E. dispar isolates in locus A-L gene. Sequences showed variation in length from 448bp to 507bp and seven distinct types were identified. The genetic diversity of loci like A-L shows them to be suitable for epidemiological studies such as the characterization of the routes of transmission of these parasites in Iran

Molecular epidemiology of cryptosporidiosis in Iranian children, Tehran, Iran

Cryptosporidium is a worldwide protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. The aim of the present study was determination of subtypes of Cryptosporidium among children with diarrhea in Tehran by sequence analysis of the highly polymorphic 60-kDa glycoprotein [GP60] gene. Fecal samples were collected from 794 diarrheic children. Initial identification of Cryptosporidium was carried out on stool samples by Ziehl-Neelsen acid-fast staining method. DNA was extracted from positive microscopically samples and Cryptosporidium genotypes and subtypes were determined, accordingly. Out of 794 collected samples, 19 [2.40%] were positive for Cryptosporidium oocysts. Sequences analysis of GP60 gene showed that 17 [89.47%] of the positive isolates were Cryptosporidium parvum and 2 [10.52%] were C. hominis. All subtypes of C. parvum isolates belonged to allele families IIa [6/17] and IId [11/17]. The most common allele in all 17 isolates belonged to IId A20G1a [41.18%]. A22G1 [IF] subtype was detected in two C. hominis isolates of the children. The predominancy of C. parvum species [specially, IId A20G1a subtype] in current study underlines the importance of zoonotic Cryptosporidium transmission in Iran

[Effect of interleukin-12 p40 subunit gene 3'-untranslated region polymorphism in chronic HCV infection]

Production of unusual cytokine levels in hepatitis C infection appears to be associated with progression of the disease, persistence of the virus in host, and establishment of chronic disease. Interleukin-12 as a heterodimeric immunoregulating cytokine is important in the generation of a Th1-based immune response. In this study we investigated the role of IL-12B 3'UTR polymorphism in susceptibility to chronic hepatitis C infection. A total of 126 chronic hepatitis C patients and 136 healthy blood donors were genotyped for IL12-p 40-3' UTR polymorphism. Genotyping was carried out by PCR-RFLP method. The results were confirmed by analyzing 10% of the samples by direct sequencing. We found no significant differences in genotype and allele frequencies of the 3'UTR polymorphism between chronic hepatitis C patients and healthy controls. There was no association between IL12B-3'UTR polymorphism and chronic hepatitis C infection. Our study can be useful in regard to the factors regulating IL-12 production, and its consequent impact on chronic hepatitis C infection susceptibility in Iranian population

[Norovirus detection and genotyping in adult patients with acute gastroenteritis in Tehran]

Human Noroviruses [NoVs] are one of the important causes of acute gastroenteritis. NoVs are highly infectious and also spread by person to person transmission through the fecal-oral route. NoVs can be classified into five major genogroups, of which genogroups I and II are recognized as the major cause of NoVs infections in human. There is not enough information about Norovirus gastroenteritis in adult patients in Tehran. The aim of this study was to determine the rate of diarrhea caused by NoVs infection in adult patients with acute gastroenteritis referring to Shohada Hospital in Tehran. From May to February 2008 we collected 67 stool samples from the patients older than 18 years of age with acute gastroenteritis. RNA was extracted and RT-PCR was performed using specific primers which could distinguish between genogroups I and II of NoVs. Three stool samples [4.5%] were positive for NoVs RNA. All of three positive samples obtained in autumn belonged to genogroup I. The mean age of NoVs infected patients was 32+8.7 years. The results of our study revealed the role of NoVs as a cause of gastroenteritis in adult patients. It's also demonstrated that genogroup I of Norovirus is the most prevalent genogroup in adults with acute gastroenteritis in Tehran