Mehdi Norouzi

Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II).

Hepatitis B virus surface protein mutations clustered mainly in CTL immune epitopes in chronic carriers: results of an Iranian nationwide study

Mutations within the coding region of hepatitis B surface antigen (HBsAg) have been found naturally in chronic carriers. To characterize the mutations of HBsAg from Iranian chronic carriers who were vaccine and/or medication naive. The surface genes from 360 patients were amplified and directly sequenced. The distribution of amino acid substitutions was classified according to different immune epitopes of the surface protein. All isolates belonged to genotype D. 222 (61.6%) of 360 patients contained at least one amino acid substitution. 404 (74.5%) of 542 amino acid changes occurred in different immune epitopes of HBsAg, of which 112 (27.7%) in 32 residues of B‐cell epitopes (62 in the ‘a’ determinant); 111 (27.4%) in 32 residues of T helper; and 197 (48.7%) in 32 residues inside cytotoxic T lymphocyte (CTL) epitopes. One Th (186–197) and two CTL (28–51 and 206–215) epitopes were found to be hotspot motifs for the occurrence of 213 (52.7%) substitutions. 20 stop codons were identified in different epitopes. There was a significant association between amino acid substitutions and anti‐HBe seropositivity; however, the correlation between such changes with viral load and ALT levels was not significant. In chronic hepatitis B virus(HBV) carriers, positive selection in particular outside the ‘a’ determinant appeared to exert influence on the surface proteins. These changes could be immune escape mutations naturally occurring due to the host immune surveillance especially at the T‐cell level.

Drug-Related Mutational Patterns in Hepatitis B Virus (HBV) Reverse Transcriptase Proteins From Iranian Treatment-Naïve Chronic HBV Patients

Background Immunomodulators and Nucleotide analogues have been used globally for the dealing of chronic hepatitis B virus (HBV) infection. However, the development of drug resistance is a major limitation to their long-term effectiveness. Objectives The aim of this study was to characterize the hepatitis B virus reverse transcriptase (RT) protein variations among Iranian chronic HBV carriers who did not receive any antiviral treatments. Materials and Methods Hepatitis B virus partial RT genes from 325 chronic in active carrier patients were amplified and directly sequenced. Nucleotide/amino acid substitutions were identified compared to the sequences obtained from the database. Results All strains belonging to genotype D.365 amino-acid substitutions were found. Mutations related to lamivudine, adefovir, telbivudine, and entecavir occurred in (YMDD) 4% (n = 13), (SVQ) 17.23% (n = 56), (M204I/V + L180M) 2.45% (n = 8) and (M204I) 2.76% (n = 9) of patients, respectively. Conclusions RT mutants do occur naturally and could be found in HBV carriers who have never received antiviral therapy. However, mutations related to drug resistance in Iranian treatment-naïve chronic HBV patients were found to be higher than other studies published formerly. Chronic HBV patients should be monitored closely prior the commencement of therapy to achieve the best regimen option.

Removal of p-nitrophenol and Naphthalene from Petrochemical Wastewater Using SWCNTs and SWCNT-COOH Surfaces

Adsorption of p-nitrophenol and naphthalene in single aqueous solution from petrochemical wastewater by single-walled carbon nanotubes (SWCNTs) and functionalized single-walled carbon nanotubes having covalent attachments of carboxylic groups (SWCNT-COOH) has been considered. Removal behavior of p-nitrophenol and naphthalene by SWCNTs and SWCNT-COOH surfaces was studied by varying the parameters such as agitation time, initial concentration, and pH of solution. The presence of surface functional groups affected the adsorption capacity of SWCNTs and SWCNT-COOH surfaces for removal of p-nitrophenol and naphthalene in single aqueous solution from petrochemical wastewater. Kinetic studies were performed and pseudo-second-order kinetic model successfully represented the kinetic data. The Langmuir and Freundlich adsorption isotherms were used for description of adsorption equilibrium, and it was found that the experimental data fitted well with the Langmuir model. The results of the study show that the carbon nanotubes can be used as potential adsorbent for petrochemical wastewater.

Removal of ethidium bromide by carbon nanotube in aqueous solution: isotherms, equilibrium mechanism studies, and its comparison with nanoscale of zero valent iron as adsorbent

The adsorption of ethidium bromide (EtBr) by single-walled carbon nanotubes (SWCNTs) and nanoscale of zero valent iron (NZVI) were investigated to assess its possible use as adsorbents. The effect of various factors, namely initial adsorbate concentration, adsorbent dosage, and contact time, were studied to identify adsorption capacity of SWCNTs and NZVI surfaces. The experiment demonstrated the maximum EtBr which was obtained at 5 min to attain equilibrium for SWCNTs and NZVI surfaces. Adsorption data were modeled with the Langmuir, Freundlichand, Temkin isotherms. Langmuir adsorption model was used for the mathematical description of the adsorption equilibrium, and the equilibrium data fitted very well with this model for both surfaces as adsorbents. The study showed that SWCNTs and NZVI surfaces could be used as new and efficient adsorbent materials for the removal of EtBr from aqueous solution. Also, the result showed that the SWCNTs were more effective than NZVI in the removal of EtBr from aqueous solution.

HBsAg mutations related to occult hepatitis B virus infection in HIV-positive patients result in a reduced secretion and conformational changes of HBsAg.

Background: Occult hepatitis B infection (OBI) is a frequent finding in human immunodeficiency virus (HIV)‐infected patients. While several related mutations in the hepatitis B virus (HBV) genome have been reported, their distinct impact on HBsAg synthesis is largely obscure. Methods: Thirty‐one (18%) out of 172 HIV‐infected patients, who were selected from HBsAg‐negative patients, were positive for HBV‐DNA assigned as being OBI‐positive. We generated a series of expression constructs of variant HBsAg with “a” determinant amino acid substitutions including P127L, P127T, S136Y, and P127T + S136Y using site‐directed mutagenesis. The expression of variant HBsAg was examined by transient transfection in hepatoma cells, followed by HBsAg immunoassay and immunofluorescence stained with specific anti‐HBs antibodies. The potential impact of amino acid substitutions at different positions for conformational changes in the HBsAg was investigated using bioinformatics. Results: All variants comprising either single or combined mutations resulted in significantly reduced HBsAg detection in supernatants and in cell lysates of hepatoma cells transfected with the constructs. Moreover, intracellular immunofluorescence staining of cytoblocks showed perinuclear and cytoplasmic fluorescence of HBsAg constructs with significantly diminished fluorescent intensity in comparison to the wild type. Altered protein conformations by predictive models, indicating an impaired detection by the hosts immune response as well as by commercial antibody‐based test assays. Conclusion: Mutations in the “a” determinant region of HBV as often found in OBI remarkably impair the detection of HBsAg from serum and infected cells, emphasizing the relevance of alternative methods such as HBV‐DNA quantification for high‐risk groups like HIV‐infected individuals. J. Med. Virol. 89:246–256, 2017.

Evaluation of HTLV-1 HBZ and proviral load, together with host IFN λ3, in pathogenesis of HAM/TSP†

Human T‐cell lymphotropic virus 1 (HTLV‐1) is associated with two progressive diseases: HTLV‐1‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T‐cell leukemia/lymphoma (ATLL). Although HTLV‐1 proviral load (PVL) has been introduced as a risk factor for these diseases’ progression, it is not sufficient on its own to yield an accurate estimation of the outcome of the infection. In the present study, PVL and HTLV‐1 basic leucine zipper factor (HBZ) expression level as viral factors, and IFN λ3 as a host factor, were evaluated in HAM/TSP patients and HTLV‐1 asymptomatic carriers (ACs). During 2014–2015, 12 HAM/TSP patients and 18 ACs who had been referred to the HTLV‐1 Clinic, Ghaem Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran, were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) were isolated and the DNA and mRNA were extracted for quantification of HBZ, IFN λ3 expression, and PVL using real‐time PCR (TaqMan method). Although the PVL was higher in the HAM/TSP group, with a 94% confidence interval, there were no considerable differences in terms of HBZ mRNA and PVL between ACs and HAM patients. IFN λ3 expression in the HAM/TSP group was significantly higher than in the ACs (P = 0.02). To the best of our knowledge, no study has evaluated the expression level of IFN λ3 in HTLV‐1 positive patients. The immune response against HTLV‐1 viral antigens and virulent factors will therefore further refine our knowledge of interactions between the virus and host in the pathogenesis of HTLV‐1‐related disorders. The virus PVL and the host IFN λ3 can be used as pathogenic factors of HTLV‐1 infected patients at risk of HAM/TSP manifestation. J. Med. Virol. 89:1102–1107, 2017.

Quantum Dot-Based Biosensor for the Detection of Human T-Lymphotropic Virus-1

ABSTRACT A method was developed to identify human T-lymphotropic virus-1 (HTLV-1) using cadmium–tellurium quantum dots. Two probes including the biotin-labeled acceptor and NH2-reporter probes with target DNA were hybridized. The resulted sandwich complex was immobilized on a well containing streptavidin. The quantum dot solution was added to the sandwich complex, conjugated with the amine group of reporter probe, and emission spectra of the quantum dots were recorded. The biosensor response was linear with HTLV-1 concentrations from 10 pg/µl to 0.24 ng/µl, with a detection limit of 19.5 pg/µl. The assay may be successfully used for detection of long nucleic acids.

Evaluation of Non-Viral Surrogate Markers as Predictive Indicators for Monitoring Progression of Human Immunodeficiency Virus Infection: An Eight-Year Analysis in a Regional Center.

Suitable methods for clinical monitoring of HIV-infected patients are crucial in resource-poor settings. Demographic data, clinical staging, and laboratory findings for 112 asymptomatic subjects positive for HIV were assessed at the first admission and the last visit from 2002 to 2010. Cox regression analysis showed hemoglobin (Hb) (HR = 0.643, P = 0.021) to be a predictive indicator for disease progression, while CD4, CD8, and platelet counts showed low HRs, despite having significant probability values. Hb and total lymphocyte count (TLC) rapidly declined from stage II to III (10.9 and 29.6%, respectively). Reduced CD4 and platelet counts and Hb during stage I were associated with disease progression, and TLC was correlated with CD4 counts at the last follow-up (P < 0.001). However, WHO TLC cutoff of 1,200 cell/mm(3) had 26.1% sensitivity and 98.6% specificity. ROC curve analysis suggested that a TLC cutoff of 1,800 cell/mm(3) was more reliable in this region. Statistical analysis and data mining findings showed that Hb and TLC, and their rapid decline from stage II to III, in addition to reduced platelet count, could be valuable markers for a surrogate algorithm for monitoring of HIV-infected subjects and starting anti-viral therapy in the absence of sophisticated detection assays.

Lamivudine Resistance and Precore Variants in Iranian Patients With Chronic Hepatitis B: Correlation With Virological and Clinical Features.

Background: Long-term lamivudine therapy, despite its initial effectiveness against hepatitis B virus (HBV), is associated with the emergence of drug resistance mutations in polymerase protein. Objectives: The aim of the present study was to determine the prevalence of precore and lamivudine drug resistance mutations in lamivudine treated patients with chronic B hepatitis. Patients and Methods: Sequential sera were obtained from 88 chronic HBV carriers who received lamivudine for more than 24 months. Polymerase and precore regions were directly sequenced for these groups: I (before treatment), II, and III (12 and 24 months after treatment, respectively). Results: All patients (100%) were contained genotype D, subtype ayw2. One (1.1%), 12 (13.6%), and 22 (25%) members of groups I, II, and III had the replacement of either isoleucine or valine instead of methionine in tyrosine-methionine-aspartate-aspartate (YMDD) motif, respectively. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an increasing trend between sequential samples (P < 0.001). In group I, 31 (35.2%); II, 36 (41.0%) and III, 41 (46.6%) members had the precore stop codon mutations. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an ascending trend between sequential samples. Indeed, frequency of precore stop codon was significantly increased with the passage of time (P < 0.001). Conclusions: Presence of drug resistance mutations among the patients was significant. Precore mutations were common amongst Iranian HBV chronic carriers under lamivudine therapy and these mutations were accompanied by clinical relapse.