Iranian

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Hepatitis B surface antigen is the first genetically engineered vaccine licensed for human use. Various strategies have been proposed to obtain a vaccine that would bypass the need for injection. In this study, a non-toxic portion of heat-stable enterotoxin of Escherichia coli that is capable of adhering to epithelial cells was inserted at amino acid position 112 of hepatitis surface antigen. The construct was used for transfection of human embryonic kidney cells in order to assess the expression of the hybrid protein. The data obtained showed a very low level of expression. In vivo antibody production and cytotoxic T lymphocyte response in B6 mice were assessed using DNA immunization. Three out of five injected mice responded with titers >10 mIU/ml anti-HBsAg and cytotoxic T-lymphocyte response was much higher with construct encoding the chimeric protein. Although this study proves that the chimeric protein is capable of eliciting both humoral and cellular responses, but further work is required to fully explore the feasibility of combining the properties of the two proteins .

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Fusion of two genes at DNA level produces a single protein, known as a chimeric protein. Immunotoxins are chimeric proteins composed of specific cell targeting and cell killing moieties. Bacterial or plant toxins are commonly used as the killing moieties of the chimeric immunotoxins. In this investigation, the catalytic domain of Shiga-like toxin (A1) was fused to human granulocyte macrophage colony stimulating factor (hGM-CSF) gene and the fused gene was then expressed using an expression vector containing arabinose promoter. The protein thus obtained could be recognized by two different ELISA system designed for detection of hGM-CSF and Shiga-toxin and reconfirmed by Western-blot. The recognition of the chimeric protein by specific antibodies could be indicative of the proper form of the protein, which justifies further steps to be taken to evaluate the potential effects of the chimeric protein. Iran. Biomed. J. 9 (4): 143-148, 2005

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We developed an immunogen to stimulate multivalent immunity against hepatitis B surface antigen (HBsAg) and hepatitis B core antigens (HBcAg). Immune responses specific for both HBsAg and HBcAg play an important role in controlling the infection. HBsAg-specific antibodies mediate elimination of virions at an early stage of infection and prevent the spread of virus. The immunogen was constructed by inserting the immunodominant, antibody-binding ‘a’ determinant (aa 111-149) of HBsAg (with or without a poly-glycine (PG) linker) into the e2 epitope of HBcAg. Only the constructs in which the HBsAg ‘a’ determinant was inserted into HBcAg, flanked by PG linkers, expressed a chimeric protein in human embryonic kidney cells with HBsAg and HBcAg antigenicity. Both glycosylated and non-glycosylated forms of the chimeric protein were immunoprecipitated from cell lysate. Intramuscular DNA vaccination of mice with plasmids expressing chimeric HBcAg primed antibody responses against well-defined serologically-defined determinants of both, native HBcAg, and native HBsAg. In addition, CD8 + T cell responses against HBcAg epitopes were primed by this chimeric HBV antigen. The e2 sequence of HBcAg can thus be used to present heterologous epitopes without loss of immunogenicity of the HBcAg protein.

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Background:The premature termination of high producer clones, which will be killed due to cell proliferation and proteins production antagonism, is one of the basic drawback in recombinant proteins technology. Furtheremore, it is supposed some toxic proteins like interferon which we intended to clone and express, inhibit host cells’ proliferation. So, it is necessary to tightly control IFN-γ production during growing and selecting of highly producing clones. Methods: In the present study, we constructed an expression vector, pMPGB43P2(6)K containing the cumate-regulatable expression cassette to high production of human IFN-γ in Chinese Hamster Ovary- Cumate Transactivator (CHO-CTA). The clones were selected in the cumate and without cumate treated medium. Results: Our results showed, induced IFN-γ expression level was about 5 of magnitude higher than the constitive transgenic system. Conclusion: Application of cumate-regulatable expression cassette, which can be switch off and on by cumate, is useful to production of high producer clones and express toxic proteins in animal cells.

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Background: In this study, the effects of three structural analogues of adenosine upon proliferation of human tumor cells were investigated. Previous research showed a cytotoxic effect of adenosine via A3 receptor and A1 receptor and sometimes this effect was receptor independent. The researches showed a differential cytotoxic effect of adenosine and its A3 agonists on cancerous cells, while other studies demonstrated tumor promoting effect of adenosine and its A1 agonists. The purpose of the present study was the evaluation of the possible selective anti-tumor effect of A1 receptor agonists on cancerous cells. Methods: The substances of N6-cyclohexyl-adenosine (CHA, A1 agonist), R-isomer of N6-phenylisopropyladenosine (R-PIA, A1 agonist) and N5-ethylcarboxamido-adenosine (NECA, adenosine A1-A2 non-specific agonist) were tested for their antiproliferative effect using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay method. Hep G2, Hep2, CACO2, ACHN and L929 cell lines were used in this assay. Results: CHA inhibited cell proliferation in three cell lines (in concentration of 5-50 µM) and R-isomer of R-PIA in one cell line (in concentration of 10-50 µM). These effects were inhibited partially by addition of 1,3-Dipropyl-8-cyclopentylxanthine (A1 antagonist). The NECA analogue had no inhibitory effect on the cell proliferations. All of the substances had no cytotoxic effect on L929 cells (mouse connective tissue fibroblast cell line). Conclusion: CHA and R-PIA had inhibitory effect on the proliferation of human tumor cell lines partially via A1 receptor, while they didn't show such effect on fibroblast cells. These results suggest that A1 adenosine receptor agonists have a good potential of specific anti-tumor activity.

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Background: Vasopressin type 2 receptor (V2R) plays an important role in the water reabsorption in the kidney collecting ducts. V2R is a G protein coupled receptor (GPCR) and the triplet of amino acids aspartate-arginine-histidine (DRH) in this receptor might significantly influence its activity similar to other GPCR. However, the role of this motif has not been fully confirmed. Therefore, the present study attempted to shed some more light on the role of DRH motif in G protein coupling and V2R function with the use of site-directed mutagenesis. Methods: Nested PCR using specific primers was used to produce DNA fragments containing aspartate-lysine-isoleucine and aspartate-arginine-tyrosine mutations with replacements of the arginine to lysine and histidine to tyrosine, respectively. After digestion, these inserts were ligated into the pcDNA3 vector and transformation into E. coli HB101 was performed using heat shock method. The obtained colonies were analyzed for the presence and orientation of the inserts using proper restriction enzymes. After transient transfection of COS-7 cells using diethylaminoethyl-dextran method, the adenylyl cyclase activity assay was performed for functional study. The cell surface expression was analyzed by indirect ELISA method. Results: The functional assay indicated that none of these mutations significantly altered cAMP production and cell surface expression of V2R in these cells. Conclusion: Since some substitutions in arginine residue have shown to lead to the inactive V2 receptor, further studies are required to define the role of this residue more precisely. However, it seems that the role of the histidine residue is not critical in the V2 receptor function.

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Background: There is a controversy about the relation between anti-hepatitis B (anti-HBs) antibody level and obesity. We designed this study to compare the vaccine efficacy in obese/overweight and non-obese cases. Methods: In this cross-sectional study, 242 obese/overweight and 85 non-obese individuals were participated. Cases were selected from a referral clinic for obesity and a referral hepatology clinic, both in Tehran, Iran.
Results: Obese cases had lower percentage of liver diseases (66.9% vs. 100%, P<0.001) but higher hepatitis B vaccination history (74.9% vs. 51.2%, P<0.001). Median±inter-quartile range of anti-HBs titer in obese cases was significantly lower than controls (48.5±194.5 vs. 100±557.6, P=0.012). Conclusion: The level of anti-HBs surface antigen antibody’s titer in obese cases without liver disease is lower than control group. Therefore, a suitable strategy is needed to overcome this problem, which can be the use of longer needles for vaccination.

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Background: Targeted co-delivery of siRNA and a chemotherapeutic drug is an attractive approach to cancer drug design and treatment. This study was carried out to design an anti-Mucin1 aptamer (Apt)-conjugated chitosan nanoparticle (NP) for targeted co-delivery of insulin-like growth factor receptor 1 (IGF-1R) Silencer siRNA and docetaxel (DTX) to SKBR3 cells. Methods: Characterization of nano-drugs, cellular uptake of NPs, cell viability, and gene expression studies were evaluated based on metastatic breast cancer cells. Results: The results of this study showed that NPs had spherical and smooth morphology with 110-118 nm in size and had positive zeta potential (12-14 mV). siRNA and DTX were considerably loaded into NPs. The appropriate conjugation of the Apt to the NPs was affirmed by gel electrophoresis. The Apt-conjugated NPs were observed to enhance the cellular uptake of NPs into the SKBR3 cells. Although the combination treatment significantly decreased the cell viability of SKBR3 cells, the augmentative effect was observed when Apt was conjugated to NPs. Furthermore, Apt-conjugated NPs dramatically reduced the genetic expression of IGF-1R, signal transducers and activators of transcription 3 (STAT3), matrix metalloproteinases (MMP9), and vascular growth factor (VEGF). Conclusion: The targeted NPs may augment the targeting of pathways involved in tumorigenesis and metastasis of breast cancer. Therefore, more animal model experiments are needed to further clarify the efficacy and safety of this functionalized nanodrug.

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Background: Leber congenital amaurosis (LCA) is a rare inherited retinal disease causing severe visual impairment in infancy. It has been reported that 9-15% of LCA cases have mutations in CRB1 gene. The complex of CRB1 protein with other associated proteins affects the determination of cell polarity, orientation, and morphogenesis of photoreceptors. Here, we report three novel pathogenic variants in CRB1 gene and then briefly review the types, prevalence, and correlation of reported mutations in CRB1 gene. Methods: Whole exome sequencing and targeted gene panel were employed. Then validation in the patient and segregation analysis in affected and unaffected members was performed. Results: Our detected novel pathogenic variants (p.Glu703*, c.2128+1G>A and p.Ser758SerfsX33) in CRB1 gene were validated by Sanger sequencing. Segregation analysis confirmed the inheritance pattern of the pathogenic variants. Conclusion: Our findings show that emerging the next-generation sequencing-based techniques is very efficient in identifying causative variants in disorders with locus heterogeneity. 

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Background: Recent studies have shown that bone marrow mesenchymal stem cells (BMSCs) have a putative ability to promote neurogenesis and produce behavioral and functional improvement. Our previous study demonstrated that co-treatment of granulocyte colony-stimulating factor (G-CSF) and BMSCs have beneficial effects on Parkinson's models. The main purpose of this research was to investigate the effects of these two factors on oxidative stress factors in the brain of Parkinson's rat. Methods: Adult male Wistar rats (weighing 200–250 g) were used and randomly divided into five groups of seven each. To create the Parkinson's model, 6-OHDA was injected into the left substantia nigra pars compacta. The BMSCs (2 × 10⁶) and G-CSF (75 µg/kg) were used for treatment after creating the PD model. After four weeks, the brains of rats were removed and processed for immunohistochemical studies, such as tyrosine hydroxylase-positive neurons as well as analysis of oxidative stress factors. Results: The results showed that the injected BMSCs could cross the BBB. The injected cells are also able to settle in different areas of the brain. Analyses of the brain oxidative stress factors showed that G-CSF and BMSCs reduced the expression of malondialdehyde and induced the activity of superoxide dismutase, glutathione, and peroxidase ferric reducing ability of plasma. Conclusion: Co-administration of G-CSF and BMSC reduced the expression of pro-inflammatory cytokines and induced the activity of antioxidant enzymes; however, neurogenesis increased in the brain. 

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Background: Inflammatory bone resorption in periodontitis can lead to tooth loss. Systemic administration of bisphosphonates such as risedronate for preventing bone resorption can cause adverse effects. Alginate hydrogel (ALG) and poly (lactic acid-co-glycolic acid) (PLGA) microparticles have been studied as drug delivery systems for sustained release of drugs. Therefore, the release pattern of risedronate from PLGA microparticles embedded with ALG was studied as a drug delivery system for sustained release of the drug, which can be used in local administrations.
Methods: Risedronate-containing PLGA microparticles were fabricated using double emulsion solvent evaporation technique. Ionic cross-linking method was used to fabricate risedronate-loaded ALG. Risedronate-containing PLGA microparticles were then coated with ALG. The calibration curve of risedronate was traced to measure encapsulation efficiency (EE) and study the release pattern. Scanning electron microscope (SEM) imaging was carried out, and cell toxicity was examined using MTT assay. Statistical analysis of data was carried out using SPSS ver. 20 software, via one-way ANOVA and Tukey’s tests.  
Results: SEM imaging showed open porosities on ALGs. The mean EE of PLGA microparticles for risedronate was 57.14 ± 3.70%. Risedronate released completely after 72 h from ALG, and the cumulative release was significantly higher (p = 0.000) compared to PLGA microspheres coated with ALG, which demonstrated sustained released of risedronate until day 28. Risedronate-loaded ALG showed a significant decrease in gingival fibroblasts cell viability (p < 0.05).
Conclusion: Alginate-coated PLGA microspheres could release risedronate in a sustained and controlled way and also did not show cell toxicity. Therefore, they seem to be an appropriate system for risedronate delivery in local applications

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Background: Freeze dried bone allograft nanoparticles on a nanofiber membrane may serve as an ideal scaffold for bone regeneration. This study aimed to assess the biological behavior of human mesenchymal stem cells (MSCs) in terms of proliferation and adhesion to nanoparticulate and microparticulate freeze dried bone allograft (FDBA) scaffolds on poly-L-lactic acid (PLLA) nanofiber membrane.
Methods: In this experimental study, PLLA nanofiber scaffolds were synthesized by the electrospinning method. The FDBA nanoparticles were synthesized mechanically. The FDBA nanoparticles and microparticles were loaded on the surface of PLLA nanofiber membrane. A total of 64 scaffold samples in four groups of n-FDBA/PLLA, FDBA/PLLA, PLLA and control were placed in 24-well polystyrene tissue culture plates; 16 wells were allocated to each group. Data were analyzed using one-way ANOVA and Bonferroni test.
Results: The proliferation rate of MSCs was significantly higher in the nanoparticulate group compared to the microparticulate group at five days (p = 0.034). Assessment of cell morphology at 24 hours revealed spindle-shaped cells with a higher number of appendages in the nanoparticulate group compared to other groups.
Conclusion: MSCs on n-FDBA/PLLA scaffold were morphologically more active and flatter with a higher number of cellular appendages, as compared to FDBA/PLLA. It seems that the nanoparticulate scaffold is superior to the microparticulate scaffold in terms of proliferation, attachment, and morphology of MSCs in vitro.

 

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Background: Hyaluronic acid (HA), a natural polymer with wide applications in biomedicine and cosmetics, is mainly produced by Streptococcal fermentation at industrial scale. In the present study, chemical random mutagenesis was used for development of Streptococcus equisimilis group G mutant strains with high HA productivity.
Methods: The optimum of the pH of culture condition and cultivation time for HA production by wild strain group G were assessed. At first, two rounds of mutation at different concentrations of NTG was used for mutagenesis. Then, the nonhemolytic and hyaluronidase-negative mutants were screened on the blood and HA agar. HA productivity and molecular weight were determined by carbazole assay, agarose gel electrophoresis and specific staining. Moreover, stability of the high producer mutants was evaluated within 10 generations.
Results: The results showed that the wild-type strain produced 1241 ± 2.1 µg/ml of HA at pH 5.5 and 4 hours of cultivation, while the screened mutants showed a 16.1-45.5% increase in HA production. Two mutant strains, named Gm2-120-21-3 (2470 ± 8.1 µg/ml) and Gm2-120-21-4 (2856 ± 4.2 µg/ml), indicated the highest titer and a consistent production. The molecular weight (Mw) of HA for the mutants was less than 160 kDa, considering as a low Mw HA.
Conclusion: The mutant strains producing a low polydisperse, as well as low Mw of HA with high titer might be regarded as potential industrial strains for HA production after further safety investigations.

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Background: Differential diagnosis of chronic lymphoproliferative disorders (CLDs) has remained challenging due to the highly variable morphology features and immunophenotyping. Currently, the development of multiple-marker panel analyses by flow cytometry has opened a broad way for diagnosis of CLDs.
Methods: We analyzed the peripheral blood and bone marrow samples of 131 patients with B-cell CLDs (including 91 chronic lymphocytic leukemia (CLL), 15 atypical CLL, 14 mantle cell lymphoma (MCL), and 11 CD5-/CD10-lymphoma patients) from April 2018 to April 2019, using a panel of specific markers by flow cytometry.
Results: Our results indicated that the expression pattern of CD22, CD23, FMC-7, and CD5 allowed us to accurately and differentially diagnose the B-CLL, MCL, and CD5-/CD10- lymphoma, while it was not capable of differentiating MCL from atypical CLL. We, however, found that the expression patterns of CD38 and immunoglobulin light chain differed significantly between atypical B-CLL and MCL. CD38 and lambda light chain were remarkably expressed in MCL patients (92.8% and 85%, respectively) compared to the atypical CLL (1.1% and 0% respectively), with the p value less than 0.001 for both markers. In contrast to MCL patients, all the patients with atypical CLL, expressed kappa light chain. The immunohistochemistry method used for cyclin D1 confirmed that the flow cytometry detection of kappa and lambda light chains could provide a new approach with high sensitivity (91%) and moderate specificity (50%) to distinguish MCL patients from atypical B-CLL.
Conclusion: Expression of CD5, CD20 (bright), CD22, FMC-7, CD38, and lambda light chain with no expression of CD23 can accurately detect MCL and differentiate it from atypical B-CLL.

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Background: Methylmalonic aciduria (MMA) is a rare inherited metabolic disorder with autosomal recessive inheritance pattern. There are still MMA patients without known mutations in the responsible genes. This study aimed to identify mutations in Iranian MMA families using autozygosity mapping and next generation sequencing (NGS).
Methods: Multiplex PCR was performed on DNAs isolated from 12 unrelated MMA patients and their family members using 19 STR markers flanking MUT, MMAA, and MMAB genes, followed by Sanger sequencing. Whole exome sequencing was carried out in the patients with no mutation.
Results: Haplotype analysis and Sanger sequencing revealed two novel, mutations, A252Vf*5 and G87R, within the MMAA and MUT genes, respectively. Three patients showed no mutations in either autozygosity mapping or NGS analysis.
Conclusion: High-frequency mutations within exons 2 and 3 of MUT gene and exon 7 of MMAB gene are consistent with the global expected frequency of genetic variations among MMA patients.

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