Pathobiology Research
Year:2010 | Volume:13 | Issue:3|Papers Count:9

Objective: Amphotericin B (AmB) is an ancient antifungal drug and proper for treatment of systemic fungal infection. Unfortunately, this antibiotic has shown some side effects such as nephrotoxicity. Therefore, recently new AmB formulated has been prepared for reduced toxicity and increased effectiveness.Materials and Methods: AmB nanocapsules prepared from polymers such as poly D, L-lactide-co-glycolide by means of a solvent displacement technique. Then, the dried nanocapsules prepared by using SiO2 and entrapment efficacy of AmB were measured by spectrophotometry technique. The MICs of these nanocapsules to Candida albicans (ATCC 90028) was also determined by using microdilution method. Then, in vitro toxicity (haemolysis) of the AmB- loaded nanocapsules determined on human red blood cells.Results: The data shows AmB entrapment efficacy for nanocapsules were 75%±0.13. The MICs of AmB-loaded nanocapsules against C. albicans tested were significantly reduced compared to that of free antibiotic. Also, the AmB-loaded nanocapsules found to be 5.89 times less toxic than free AmB on human red blood cells.Conclusion: The results suggest that prepared AmB-loaded nanocapsules in this research may be an appropriate delivery system for AmB to be used in the treatment of fungal infections.

Objective: Silicon is an effective element in bone biomineralization; hence Si-substituted hydroxyapatite can be a relevant bioceramic as bone materials substitution.Materials and Methods: Stoichiometric hydroxyapatite (HA) and Si-substituted hydroxyapatite (Si-HA) with different contents of Si substitution were synthesized successfully by a hydrothermal method using Ca(NO3)2, (NH4)3PO4 or (NH4)2HPO4 and Si(OCH2CH3)4 (TEOS) as starting materials.Results: Crystalline Phases, chemical composition, microstructure and morphology of synthesized powders were investigated using X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), inductively coupled plasma AES (ICP-AES) and scanning electron microscopy (SEM) techniques. The results proved silicon substitution in hydroxyapatite structure and revealed that the substitution of phosphate groups by silicate groups caused some OH- loss to maintain charge balance and the lattice parameters slightly changed with respect to stoichiometric HA.Conclusion: Si-incorporation reduces the crystallites size of Si-HA and crystallinity, thus the solubility of Si-HA powders increases, and as a result Si- substitution has improved bioactivity behavior of HA. Based on in-vitro tests; soaking and incubating the specimens in simulated body fluid (SBF) and MTT assays (Dimethylthiazol assay), Si-substituted hydroxyapatite is more bioactive than pure hydroxyapatite.

Objective: Escherichia coli is the most prevalent etiologic agent of urinary tract infections which is the cause of about 80% of cases. Enzymatic inactivation of aminoglycosides by aminoglycoside-modifying enzymes is the main mechanism of resistance to these antibiotics in Escherichia coli. The aim of this study was the detection of aac(3)-IIa gene among aminoglycoside resistant clinical isolates of E. coli using PCR method.Materials and Methods: After collection of 250 clinical isolates of E. coli, antibiotic susceptibility patterns of isolates were determined by disk diffusion method for gentamicin, amikacin, tobramycin, kanamycin and netilmicin by considering the CLSI principles. Chromosomal and plasmid DNA of the isolates were extracted using DNA extraction Kits and PCR method was used for detection of the aac(3)-IIa  gene.Results: Results show that 96% of E. coli isolates were resistant to tobramycin, 90% resistant to kanamycin, 82% resistant to gentamicin, 30% resistant to netilmicin and 8% resistant to amikacin. aac(3)-IIa gene was detected in 54.83% of E. coli isolates.Conclusion: Because of high prevalence of resistance toward aminoglycoside antibiotics which is due to its transfer among bacteria by transferable elements such as transposons and plasmids. Therefor, tracing transfer routs among different bacteria is very important.

Objective: As we are approaching the global eradication of wild poliovirus, laboratory surveillance of poliovirus by the gold standard cell culture method becomes increasingly important. As there is a lot of concern about accurate and sensitive detection of imported wild and Vaccine Derived Polioviruses (VDPVs) in Polio-Free countries, in this study we assessed and compared the sensitivity of the cell lines used in polio laboratory simultaneously to standard poliovirus and Oral Polio Vaccine (OPV) polioviruses, to ensure the accurate detection of circulating and imported polioviruses in the society.Materials and Methods: Cell sensitivity test was performed according to the World Health Organization (WHO), Polio Laboratory Manual for RD, L20B and Hep2 cell lines using 3 serotypes of standard monovalent and OPV polioviruses. The test was repeated every four passages for all cell lines.Results: The sensitivity of L20B and Hep2 cell lines for standard poliovirus type 1 and 2 is more than sensitivity for the same types of OPV virus but for poliovirus type 3 it is vice versa. Also RD cell line is more sensitive to all 3 types of OPV virus. In addition, the test showed that increasing the passage number will decrease the sensitivity of all cell lines.Conclusion: Using RD & L20B cell lines simultaneously (with low passage number) will assure us of sensitivity and accuracy of the cell lines for detection of circulating and imported polioviruses.

Objective: Prostate cancer is one of the most common cancer in the developed countries. Most of cancer deaths are due to development of metastasis. Hence, prevention of metastasis is critical. Silibinin is a flavonoid component that inhibits cell proliferation and causes cell death of human prostate cancer. In this study, the expression of CD82 gene in PC-3 cells treated with escalating concentrations of silibinin was evaluated which can result in new view for prostate cancer therapy.Materials and Methods: In this study, PC-3 cells were treated with different concentrations of silibinin for 24h. The LD50 was determined. RNA was extracted by trizol, and then cDNA was synthesized. Precise primers were designed for CD82 and GAPDH genes by specific software. Quantity of CD82 gene expression compare to GAPDH gene in different concentrations of silibilin was analyzed using very sensitive quantitative Real-time PCR.Results: CD82 gene expression in PC-3 cells treated with 100, 150 and 200 mg/ml of silibinin at 24h was increased by 1.97±0.26 (P<0.05), 3.00±0.26 and 3.43±0.43 (P<0.01), respectively.Conclusion: The results of quantitative Real-time PCR indicated that silibinin can probably decrease metastasis, by up-regulation of CD82 metastasis suppressor gene in PC-3 cells.

Objective: Average Age of population in the industrial countries has increased. Because of aging the percent of the diseases related to the oldness such as multiple myeloma have also increased. It has both common and unique symptoms and effects. The unique effects include wide bone reabsorption. It seems necessary to understand the structure of Bone Marrow Niche and the effects of Myeloma cells on adjacent hematopoietic Stem cells with a new approach.Materials and Methods: We have studied the differentiating effect induced by the Myeloma cells through co-culturing the Myeloma cells and hematopoietic stem cells, extracted out of cord blood. In this investigation we also cocultured myeloma cells with the monoblastic cell line (U937) in order to evaluate the effect of myeloma cells on monoblastic cells differentiation.Results: Our findings show that increased expression of myeloid and monocytoid markers in coculturing of myeloma cells and HSCs. Moreover following monoblastic and myeloid cells coculturing, we observed probably TRAP positive osteoclastic like cells.Conclusion: Our findings show that presence of myeloma cells in Bone Marrow play essential role in HSCs differentiation to monocytoid (osteoclastic) lineage.

Objective: Allogeneic transplantation with umbilical cord blood (UCB) in adult recipients is limited mainly by a low CD34+ cell dose. To overcome this shortcoming, human placenta as a novel source of human mesenchymal progenitor cell (MPC)- unrestricted somatic stem cells (USSC)- was incorporated in an attempt to expand CD34+ cells from UCB. To provide a similar environment in vitro, we coated DBM scaffold with USSC cells as the matrix for support UCB-CD34+ cells growth.Materials and Methods: Human placenta USSC was isolated and characterized by morphologic and immunophenotypical analysis. UCB CD34+ cells were expanded by coculture with placental USSC in 2D and 3D environment. Suitable aliquots of cells were used to monitor cell production, clonogenic activity, and long-term culture-initiating culture (LTC-IC) output.Results: Ex vivo expansion of UCB hematopoietic cells, when cultured in different 2D conditions and 3D condition for 3 weeks, was significantly enhanced, the total cell count increased within the 28-day period. For total CFC, the highest CFC expansion was observed at day 14. Flow cytometry analysis of the percentage of CD34+ cells showed a decline in USSC cocultures in 2D and 3D condition at 3 weeks.Conclusion: These results strongly suggest that human USSC may be a suitable feeder layer for expansion of hematopoietic progenitors from UCB in vitro and USSC- coated DBM can therefore provide an ex vivo mimicry of bone marrow by enhancing of surface/ volume ratio and feeder layers, recapitulate the desired niche, and provide a suitable environment for stem cell expansion and differentiation.

Objective: Hepatitis C virus (HCV) is one of the most relevant persistent infections afflicting the human population. Control of viral replication in HCV infection has been associated with the cellular component of the host immune response. Several mechanisms have been proposed to explain this abnormal immune response, among them an altered activity of regulatory T cells (Tregs) being the most recently postulated. As the first report, in the present study the ability of HCV-core antigen in increase the frequency of natural Tregs (nTregs) in the mixed population of PBMCs was evaluated.Materials and Methods: Peripheral blood mononuclear cells (PBMCs) from chronic HCV infected patients (n = 19) and normal controls (n = 6) were analyzed to study the effect of HCV-core antigen in frequency of HCV specific nTregs. For this, PBMCs of different groups were isolated, cultured and stimulated with core antigen. Then an in-house triple-stain flowcytometric method was used to investigate the frequency of nTregs.Results: The results showed that, following incubation with HCV-core Ag, a population of nTregs was increased but, in negative controls the number of nTregs did not increase.Conclusion: The present data supporting the idea that nTregs are able to respond specifically to HCV antigen suggests that Tregs could contribute to an inadequate response against the HCV infection, leading to chronic infection and supports the view that specific natural Tregs may be implicated in host immune tolerance during HCV infection. It is reasonable that HCV vaccine candidates avoid epitopes that lead to strong nTregs stimulation.