Iranian Biomedical Journal
Volume:6 Issue: 1, Jan 2002

Unresponsiveness to hepatitis B surface antigen (HBsAg) has been shown to be associated with dysfunction of the presenting cells (APC) and defect in the specific B-lymphocyte and/or T-lymphocyte repertoires. Direct determination of the frequency of specific T-lymphocytes together with complementary analysis of the naive circulating immune cells could provide valuable information about the cellular basis of unresponsiveness to HBsAg. In this study, the phenotypic characteristics of peripheral blood mononuclear cells (PBMC) from healthy adult high-responders (n = 19), intermediate-responders (n = 11), low-responders (n = 9) and non-responders (n = 6) to recombinant hepatitis B vaccine were investigated and compared. The proportions of circulating B-lymphocytes (CD19+ cells), T-lymphocytes (CD3+ cells) and monocytes (CD14+) were similar in all groups ofresponder individuals (14%, 55-60% and 11-13%, respectively) compared to non-responders (16%,64% and 9%, respectively). These results suggest that the cellular basis for the lack of response toHBsAg is not associated to a generalized deficiency of immune cells in the non-responder subjects,rather it may reflect a defect in HBsAg-specific B or T cells.

Avian influenza is an important disease of poultry with the potential to cause major epidemicsresulting in significant economic losses. The presence of avian influenza viruses (AIV) in chickens inIran has not been previously reported. An avian influenza outbreak in broiler, layer and breederfarms occurred during a very hot summer in July 1998. Three AIV isolates designated as 101, 102 and103 were isolated from lung, tracheal cloacal samples of layer, breeder and broiler chickens, inembryonated chicken eggs. The presence of AIV in allantoic fluid cells was confirmed by indirectimmunofluorescence assay using a monoclonal antibody against type A nucleoprotein. The viruseswere further classified as H9N2 subtype in hemagglutination inhibition and neuraminidase inhibitiontests using 15 hemagglutinin and 9 neuraminidase subtype specific antisera. The pathogenicity of AIVisolates was carried out in 4-6-wk-old chickens. No birds died within 10 days after inoculation ofinfectious allantoic fluids. Therefore, the representative Iranian layer, breeder and broiler AIV strainswere classified as non-highly pathogenic avian influenza viruses pathotype. Isolation of the samesubtype and pathotype of AIV from different flocks suggested that the H9N2 AIV subtype is acommon pathogen involved in poultry industry respiratory disease outbreak.

1Zahedan University of Medical Sciences, Zahedan, Iran; 2German Cancer Research Center, Heidelberg, Germany; 3Tehran University of Medical Sciences, Tehran, Iran; 4Gorgan Laboratory of Pathology, Gorgan, Iran; 5Gorgan University of Medical Sciences, Gorgan, Iran ABSTRACT Human papillomavirus (HPV) DNA has been identified in esophageal carcinomas. However, the incidence of HPV varies significantly in different geographical locations. In this study, neoplasms from Turkmen Sahra, a region in Golestan province in northeast part of Iran, with a high incidence of squamous cell carcinoma were analyzed for the presence of HPV DNA. Turkmen Sahra is located in the cancer belt in Asia. Eighty-five squamous cell carcinomas were examined for the presence of HPV DNA. PCR was utilized to amplify a 124-bp segment of the HPV L1 gene using the consensus primers. The amplified region was subsequently sequenced to identify the HPV. The results indicated that the rates of HPV detection in squamous cell carcinoma specimen for men and women were 52.8% and 43.7% respectively. The positive cases included HPV-16 (54.7%), HPV-18 (4.8%), HPV-6 (14.3%), HPV-66 (7.1%), HPV-52 (4.8%) and 14.3% of cases were positive for more than one type of HPV. Human papillomavirus type 16 that can be potentially oncogenic was prevalent in 54.8% of the cases of esophageal squamous cell carcinoma. Our results confirm the previously reported HPV involvement in the esophageal squamous cell carcinoma, and support the possible role of HPV as an etiological agent in esophageal carcinogenesis.

In this study, mutant forms of Bacillus thuringiensis spp. israelensis (H14) were produced. Thesemutants were identified when the cells were cultured on chloramphenicol plates and stained withcrystal violet. Protoplasts of the mutants were isolated by enzymatic digestion (lysozyme) of the cellwalls at the presence of an osmotic stabilizer. The protoplasts were induced to fuse to each other in thepresence of PEG 6000. The frequency of regeneration and recombination was 80% and 2×10-4,respectively. In order to survey the effect of protoplast fusion on production of toxin, anti-serumagainst pure toxin was raised in rabbit and was used in single radial immunodiffusion. Thecomparison of δ-endotoxin concentration between B. thuringiensis fusion and the wild type strainsshowed that B. thuringiensis fusion has 1.48 time more toxin than wild type.

Cloning and expression of the L-phenylalanine dehydrogenase gene, from B. sphaericus in E. coli weredone. The gene was cloned in the vector pET16b and transformed into E. coli BL21 (DE3). Thefunctional form of the L-phenylalanine dehydrogenase enzyme was purified by affinity purificationtechniques, taking advantage of the ability of this enzyme to bind to the nucleotide site affinity dye,Reactive Blue 4. Approximately 3 mg of highly purified recombinant enzyme was obtained from 950mg cell pellet (wet weight). The Relative molecular mass of the L-phenylalanine subunits was about 41kDa by 10% SDS-PAGE. Using this method, the enzyme was obtained with a yield of 28%, and had aspecific activity of 577.3 U/mg protein, which is purified 88 times. This method was provided a facileand effective way for preparing the enzyme with a good yield that suitable for analytical purposes.

In order to find a prophylactic supplementation for individuals who are at risk of exposure to ionizingradiation, we attempted to evaluate the effect of Vitamin E (Vit-E), a biological free radical scavenger,on restoration of hepatic lipid peroxidation (LPO) and lipid profile (LP) changes induced by sublethalγ- radiation in BALB/c mice. The concentrations of cholesterol and phospholipid were determined incontrol and irradiated mice. Also, changes in lipid peroxidation and lipid profile were assessed bymeasuring the level of malonyldialdehyde, lipid hydroperoxides, and conjugated dienes. Our resultsshowed that sublethal γ-radiation caused significant changes in hepatic lipid peroxidation and lipidprofile. However, Vit-E supplementation was able to restore the changes of lipid peroxidation andlipid profile in irradiated mice. We have concluded that the mice that received Vit-E supplementationwere able to tolerate biomembrane damage provoked by 1.09 Gy for 3 days γ-radiation. This supportsthe hypothesis that Vit-E may afford an efficient protection against ionizing radiation. Howeveradditional studies using higher doses of γ-irradiation should be performed.

The enzymatic potential of the cultured plant cells can be employed for bioconversion purposes. Plantenzymes are able to catalyze regio- and stereo-specific reactions, and therefore can be applied for theproduction of desired substances. The biotransformation of foreign substrates with suspension cellsof Peganum harmala was tested with (±) phenylethyl propionate. The callus cultures of Peganum harmala were established from cotyledons, and healthy suspensions grown using Murashige and Skoog medium. In order to investigate the specificities of the hydrolysis, (-) and (+) phenylethyl propionateisomers were added to the cultures. The phenylethyl propionate isomers were converted to their corresponding alcohols. The two isomers showed different rates of conversion during the first 24 hours after feeding. These cultures were able to hydrolyse specifically the propionate group in (±) phenylethyl propionate. It was found that the cultured cells of P. harmala have the ability to hydrolyse the racemic phenylethyl propionate stereoselectively.