Pathobiology Research
Year:2006 | Volume:9 | Issue:1|Papers Count:9

Aim: This study investigates the intraspecific competition, for food and density amongst larvae of Anopheles stephensi (main malaria vector in south Iran). Material & Methods: The effects of 4 selected food quantities (1x,2x,4x,6x) and 5 larval densities (0.1 to 3 larvalcm2) were tested individually or in combination on 7 biological indexes of the vector and the results were statistically analyzed. The competition starts when the food quantity decreases from 6x to x and the larval density increases from 0.1 up to 3 larvalcm2.Results & Discussion: The biological indexes that showed significant alterations at competing conditions (reduced food quantity and increased larval density) were as follows. Increasing of the larval, pupal and total mortality, alteration of the sex ratio in favor of male production, and decrease of the speed of larval development and survival rate. However, body sizes did not show any significant difference among individuals of both sexes.Conclusion: So, reducing the food quantity and increasing the larval density make a decrease in abundance and activity of An. Stephensi and it may provide a useful method for control of this mosquito population.

Introduction: Hepatitis C virus (HCV) is the major cause of acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma worldwide. Because of increasing number of infected patients throughout the world, various studies are concentrated on development of high quality diagnostic tests and genotyping in various regions of the world.Methods: In this study, we used RT-PCR to isolate and amplify the core gene sequence of the hepatitis C virus that is very conserved among various genotypes, from an isolate derived from an Iranian patient with chronic hepatitis. Then it was cloned in pue 18 vector and sequenced with universal primers. In order to produce recombinant core protein, the core gene was cloned in PET28A expression vector and the recombinant plasmid was transformed into BL21 (DE3) bacteria.Results and Discussion: The results of sequencing showed that the core gene of the hepatitis C virus from an isolate derived from an Iranian patient with chronic hepatitis has a higher similarity with la (96%) and 1b (95%) strains of the virus. This result is similar to those obtained by previous studies. The presence of a 23.5 KD band in SOS-PAGE and Western blot using monoclonal antibody, proved the expression of Core protein in PET28A vector. Mass production of this protein could lead to its use in detection of anti-HCV antibodies in infected patients by immunoassays.

Objectives: Toxoplasma gondii is a coccidian protozoon which forms tissue cyst in different organs of infected intermediate host. The present study was conducted to demonstrate the active form of parasite in different tissues of rat, which was experimentally infected with RH strain of Toxoplasma gondii using bioassay method inmice.Materials & Methods: In the experimental assay, 75 rats and 500 mice were used. The rats were infected experimentally with 40-50 thousands of tachyzoites intrapritoneally. Three rats were killed every 24 h then with up to three days 3 days interval for 60 days and their different organs were searched biologically for presence of the parasite. In this regard, the organs were squeezed with mortar in normal saline, diluted and following adding streptomycin and penicillin injected intrapritoneally in three outbreed mice each. Then the mice were followed up for 10 days.Results: Toxoplasma cyst was found in brain, liver and spleen of the rats within 5 to 9 post infection. The parasite was appeared in heart and muscles within 9-13 days after infection but not found in the kidney. The parasite was disappeared in spleen and liver following 12 and 28 days of infection respectively but remains active in the brain, heart and muscles within 60 days of the study.Implication: Toxoplasma gondii could remain active in spleen and liver of infected rat for a short time. Meanwhile brain and muscles (heart and skeletal muscles) of the infected animal can keep the parasite for a long time. Kidney is not appropriate tissue for Toxoplasma gondii localization.

Background: Rheumatoid Arthritis (RA) is the most common chronic inflammatory erosive joint disease with the worldwide distribution of approximately 0.5-1%. Molecular methods can be very sensitive in the early stage diagnosis of the disease and therefore prevention the late complications and disabilities. Etiology of RA, an auto immune disease, is not exactly known but immunologic and genetic factors seem to play important roles in the pathogenesis of the disease. Genetic factors such as Human Leukocyte Antigens (HLA) are responsible for many autoimmune diseases; therefore we decided to look for a correlation between RA and the presence of specific HLA-DQB1 alleles as a possible genetic markers.Methods: The genomic DNAs from the whole blood samples of 25 patients with RA and 86 normal individuals (Control group) were extracted by salting out method. The genomic DNA was amplified by PCR-SSP technique. HLA-Typing was done by this method after optirnizing the PCR reaction for each allele. In this procedure seven serological subclasses of HLA-DQB1 can be detected. Results: Comparing the results between the patients and the controls suggests a significant increase in the frequency of HLA-DQ5 (*0501-*0504) and HLA-DQ8 (*0302, *0305) alleles in the patient group.The P-values were respectively 0.033 and 0.007 (P<0.05)(DQ5 and DQ8 positive individuals in patients were respectively 56% and 24% compared with 31.4% and 5.8% in healthy people). The relative risk for these alleles was evaluated higher than 1.Conclusions: The results suggest that DQ5 and DQ8 are the dominant HLA-DQBl alleles that are associated with the susceptibility to RA. These alleles are probably important in increasing the risk of developing RA disease in Northeastern Iran and we can use them as molecular markers for diagnosis of RA.

Background: Lipophilic yeasts of the genus Malassezia has been placed among the Basidiomycota phylum in the family of Cryptococcaceae. The genus Malassezia comprises yeasts with a natural habitat of the skin of many warm-blooded vertebrates, and human, but they are also associated with several skin diseases such as tinea versicolor, seborrehoeic dermatitis and even systemic infections. The genus Malassezia has recently been revised to include nine species by biochemical, morphological and molecular findings.Materials and methods: This study was aimed at the development of a DNA-based procedure applicable to rapid laboratory confirmation and identification of each Malassezia species. At first, conventional identification methods based on macroscopic, and microscopic features and physiological properties was performed. In the molecular findings a specific and unique restriction pattern was determined for each of the three currently recognized Malassezia species.Results: The primers ITS/4 produced a large amplificon (about 800 bp for M. furfur, and M. globosa) and the other amplificon is smaller (about 600 bp for M. sympodialis). For further species distinction with this amplicon, one restriction endonuclease proved tobe useful. Restriction patterns obtained by ECORI digestion of amplified products from the ITS region was distinguish.Conclusion: Application of polymerase chain reaction (PCR) technology for molecular diagnostics allows early and accurate identification of Malassezia Spp. The PCR-RFLP results were well correlated with those obtained from traditional identification procedures.

The family of staphylinidae (rove beetles) includes 40000 species and has a world-wide distribution. Many species of Paederus have been known for a long time as the causative agent of linear dennatitis. Paederus beetles are attracted to artificial lights in the evening during the hot and humid summer nights. Whenever they are crashed or smeared on the skin they release their toxin called Pederin from their haemolymph.So far, various recommendations have been made to control paederus, but most of them were inefficient. The aim of this study was to investigate the repellency effect of the neem oil (Azadirachta indica Juss), as a personal protection method against paederus beetles.Neem oil was used in three different dosages (2.5, 5, 10 percent) on treated paper inside the ptri dishes. The results showed that protection percentage produced by Neem oil at 2.5 ,5 and 10 percent dose was 46.2, 69.3, 84.62 percente respectively.

Introduction and aim: Diagnosis and treatment of urinary tract infection in children must be done before renal damage. So, in many countries the screening programs are done in the schools. There are a few reports on the prevalence of this disease among children in different parts of Iran. This study aims to investigate the prevalence of this infection in the seven years old children of Birjand city and determine the worth of recommending a screening program for the UTI before attendance to school, this study was performed.Methods: 278 Students (148 boys and 130 girls) were selected by multi stage cluster sampling. After filling the questionnaire, urine culture was done. In those who had colony count above or equal 104 per ml and below 105, U/C was repeated. Children with 105 colony count per ml had documented as UTI. Results: The prevalence of UTI was 1.1% in all students. The prevalence of UTI was 1.4% in boys and 0.8% in girls. There was not any significant difference in the prevalence of UTI between two sexex (P.Value =1).68.9 % of the boys (102 persons) were circumcised. The prevalance of UTI was 1% in circumcised boys and 2.2% in uncircumcised ones. There was not any significant difference in UTI between these two groups (Pvalue = 0.53). the most common age of doing circumcision was six years old. We had only Ecoli in the results of all documented UTI.Conclusion: Regarding to a few information about the prevalence of UTI among children in different parts of Iran, it is better to conduct more studies to determine the worth of recommending a screening programs for UTI in pre-school age. We recommend giving more information and education to people about the best age for circum cision.

Patients afflicted by diabetes mellitus (DM) usually have more infections than those without DM. The course of the infections is also more complicated in this group of patients. One of the possible causes of increased infections prevalence is a deficiency in the immunity. Besides some decreased cellular responses in vitro, no disturbances in adaptive immunity in diabetic patients have been described. Different disturbances (low complement factor 4, decreased cytokine response after stimulation) in humoral innate immunity have been described in diabetic patients. In this research hydrogen peroxide (reactive oxygen mediator) and nitric oxide (reactive nitrogen mediator) in the neutrophil and macrophage culture of peritone in rats were evaluated against C.albicans. Via intravenous injection of streptozocin (65 mg/kg), a diabetic rat model was obtained. nitric oxide and hydrogen peroxide assay was performed by the Griess and Walter-Ruch methods respectively. C.albicans colony count on SCC medium was also done in two groups of healthy and diabetic mice.Macrophages of the healthy group reacted to C.albicans severly compared to the diabetic group which significantly produced more nitric oxide (p£0.028). Neutrophils of the healthy group produced more No compared to the diabetic group against C.albicans (P£0.165). No considerable difference was observed in production of hydrogen peroxide by macrophages in two groups of healthy and diabetic mice. Neutrophils of the diabetic group produced more hydrogen peroxide compared to the healthy group (P£1). There was no significant difference in C.albicans colony count between the two healthy and diabetic groups (P£0.058).Although nitrogen and oxygen related factors are changed or reduced after diabetic induction, changes in other immune system factors cannot be undermined.