Pathobiology Research
Year:2004 | Volume:7 | Issue:1|Papers Count:12

Purppose: Embryonic stem (ES) cells are pluripotent cells conventionally isolated from the inner call mass of preimplantation embryos. ES cells can be maintained as stable, proliferative and undifferentiated cell lines if cultured in the presence of leukemia inhibitory factor (LIP) or on feeder layers (primary embryonic fibroblasts or STO fibroblasts). Feeder layers synthesize and secrete LIP into the culture medium. Since, based on several evidences, LIP is secreted by mitomycin pretreated Vero cells (a cell line isolated from the green monkey kidney epithelial cells), the main goal of this study was to demonstrate that ES cells can be isolated by using Vero cells as a feeder layer. The criteria used for the evaluation of undifferentiated ES cell phenotype in this study were morphology, evaluation of alkaline phosphatase activity, formation of embryoid bodies (Esb) and neural differentiationMaterial and Methods: Fully expanded blastocysts were obtained by mating superovulated NMRI female mice and cultured individually on mitomycin C- inactivated Vero cells. After 4-5 days in the culture, The ICMs were plucked off and partially disaggregated in a 0.25% trypsin/EDT A solution. Three to four days later the compact ES cells colonies could be identified. The colonies were dissociated and reseeded on a freshly-treated Vero feeder layer. The cultures were scanned periodically and all the ES cell colonies were passsaged sequentially in the three days intervals. Alkaline phosphatase was detected histochemically, following the fixation of the colonies with 100% ethanol- using α- naphtyl phosphate as a substrate. The undifferentiated mouse ES cells derived on the Vero cells in our laboratory were induced to differentiation using retinoic acid by the 4-/4+ protocol. Several days later, some of the resulting cells posses a neuron-like cell morphology.Results: The resulting cells had high ratio of nucleus to cytoplasm, prominent nucleuli, and a colony morphology similar to that of the murine ES cells. The ES cell colonies expressed the cell surface markers that characterize the undifferentiated ES cells, including alkaline phosphatase.Conclusion: We concluded that Vero cells as a feeder layer may present an alternative avenue in obtaining pluripotent ES cell lines. Although, the application of Verocells in the ES cell culture still requires further investigation.

Introduction: Glycoprotein B of herpes simplex virus type 1 (gB-1) is one of the surface membrane glycoproteins of the virus, which is of great importance in virus infectivity, and is a target for immune system. The main aim of this research was to express gB-1 gene in eukaryotic cells.Methods: The gB-1 gene was subcloned from pAc-gB plasmid to pcDNA3 expression vector under control of CMV promoter. The right orientation of the inserted gene was then determined using restriction enzyme analysis. In order to examine expression of the gene in eukaryotic cell, the plasmid was transfected to the COS-7 cells, using liposome. In vitro expression of gB protein was determined using immunoflurescent techniques.Results: Results showed that the protein of interest had been synthesized in the cells, 72 hours after transfection.Discussion: Expression of gB in COS-7 cells and its interaction with specific antibody, confirmed efficacy of constructed vector in expression of gB protein with suitable antigenic structure that can be used in vaccination studies.

Purpose: Neural networks (NNs) have received a great deal of attention over the last few years. They are being used for prediction and classification areas where regression models and other related statistical techniques have traditionally been used. The aim of this study was to compare the abilities of neural network (ANN) and logistic regression (LR) models to predict the risk of in- hospital mortality after coronary artery graft (CABG) surgery.Materials and Methods: A NN model was developed using the training set of 150 patients undergoing CABG surgery at Shariatie Hospital, in Tehran, in 1997. Then, it was validated in a test set of 160 patients having CABG surgery in 1998.The NN was consisted of 18 input, 4 hidden and 2 output neurons with a back-propagation algorithm (learning rate 0.12, training tolerance 0.5, sigmoid transfer function, and niaximum error 0.01).Results: At the end of the learning, the NN was able to recognize CABG, SM, HTN, and LVF variables, as important factors. The sensitivity and specificity in the training set were 100%, and in the testing set they were 99.33% and 100% respectively. In the LR model, CABG, SM, HTN variables were entered in the model. For this model, the sensitivity and specificity for the prediction of patient events (death survival) were 99% and 100% respectively.Conclusion: The prognostic accuracy of the NNs was better then LR models (ROC area 0.811 vs 0.791) and their calibration was better. The NN successfully estimated and predicted the risk of in hospital mortality rather than LR model, with regard to the selected factors.

Purpose: Our purpose was to determine the effect of transcutaneous electrical nerve stimulation (TENS) on the synaptic activities of spinal cord and H- reflex and Mh wave parameters of antagonist muscle.Materials and Methods: 10 healthy nonathletic male volunteers were tested in two experimental sessions (control and test ). In the test session, two separate of TENS for a period of 10 minuts were delivered at 100 Hz and 300 µs pulse width on tibialis anterior muscle (catode on the belly of tibialis anterior muscle and anode on common proneal nerve). In the control session no current was passed through the electrodes.Results: Statistical analysis indicated that after TENS, peak to peak amplitude and area under the curve (ARV) of soleus H-reflex have been decreased significantly( p<0.05 ). These parameters were increased for the soleus Mh wave.Conclusion: The results demonstrated that the neuromuscular electrical stimulation of tibialis anterior causes an increase in the sensitivity of its motor end plate. On the other hand this stimulation caused an increase in the renshaw cells activities and its inhibitory effects on soleus motor neurons.

Purpose: Lipopolysaccharide (LPS) is a major constituent of gram negative bacteria cell wall. LPS consistes of three covalently linked components of (i) lipid A (endotoxine A), (ii) core (oligosaccharide) and (iii) the a-antigen polymer (polysaccharide). LPS preparations are used extensively for research in the elucidation of the LPS structure, metabolisme, toxicity and biosynthesis. The LPS is also used as a mitogen for B- lymphocytes proliferation. The purpose of this study was to evaluate the extracted LPS as a mitogen by the MTT assay.Materials & methods: Escherichia coli was grown in the nutrient broth (NB) and after the harvesting, the bacteria were washed with ethannol, aceton or chloroform- methanol. The LPS was extracted by two different methods of Phenol- chloroform- petroleum ether (PCP) and Methanol-Chloroform (MC). In the MC method, the bacteria was sonicated and then the LPS was extracted. In the PCP method, Petroleum ether and chloroform were removed on rotary evaporator or in a high vacuum at a degree bellow 0°C and the precipitated LPS was washed two to three times with ether to remove any remaining phenol. We measured the B cell proliferation by using the MTT assay. We also used the cell viability assay with the trypan blue dye as a qualitative assay. In the MTT9 assay different concentrations of extracted LPS and standard LPS (Sigma) were added to 96 well plates containing 2.5x104 cells/well. These cells were separated from the whole blood by ficoll and suspendd in a complete RPMI-1640 medium. We measured the 0.0 of the MTT dye at 570 nm and 620 nm respectively.Results: Our result showed that the cellular proliferation by the PCP-LPS was more than the MC-LPS, compared to the control (cells without LPS) and was similar to the standard LPS.Conclusion: In conclusion, the PCP-LPS has more mitogeneic activity compared to the MC-LPS.

Purpose: The role of adenosine AI receptors of the nucleus accumbens on amygdala kindled seizures was investigated.Materials and Methods: All animals were implanted with a triplolar (stimulating and recording) electrode in the amygdala and tow guide cannula in the nucleus accumbens. Animals were kindled by daily electrical stimulating of the amygdala. In the full kindled animals, N6- cyclohexyladenosine (CHA; 1, 5 , 10 µM), an adenosine A1 receptor agonist, was injected bilaterally into the nucleus accumbens.Results: Obtained results showed that CHA at the concentration of 10µM reduces the amygdala afterdischarge duration (A-ADD), at 5, 15, 60 and 120 min post drug injection. It also decreased the stage 5 duration (S5D), but reduced the accumbens afterdischarge duration (Acc-ADD), at 15 min post drug injection, and increased the latency of the stage 4 seizure (S4L) at 5 and 15min post drug infusion. In addition, at the concentration of 5 µM, the S4L was increased and the S5D was decreased at 5 and 15 minpost drug injection. The bilateral injection of8- cyclopenthyl-l,3- dimethylxanthine (CPT), an adenosine A1 receptor antagonist, at the concentration of 5 µM into the nucleus accumbens did not alter the seizure parameters. The intra- nucleus accubens infusion of CPT (5µM), 5 min before CHA (10µM) blocked the anticonvulsant effects of CHA.Conclusion: These results suggest that the nucleus accumbens has a role in the seizure propagation from the amygdala and it's adenosine AI receptors activity has anticonvulsant effects in amygdala kindled rats.

Purpose: In the present study, the effects of nicotine on the expression of conditioned place referenced (CPP) induced by morphine in mice have been investigated.Materials and Methods: Male albino mice (W: 20-25gr) were used in this study and the conditioned place preference was induced by the Carr method.Results: Subcutaneous (s.c) injection of morphine (5 mg/kg) can produce a place preference. Furthermore, intrepretoneal (i.p.) (0.0025, 0.005 and 0.01 mg/kg) and intracerebroventricular (i.c.v) (0.003, 0.1 and 0.3 ng/mice) administration of nicotine significantly decreases the expression of CPP induced by morphine. However, nicotine alone in the mentioned doses doesn't cause motivational effects. It appears that the i.c.v preadministration of the animals with peripheral nicotinic acethyiecholine receptor antagonist, hexamethonium (0.03, 0.1 and 0.3 mg/mice; 10 min before nicotine) but not with i.p. hexamethonium (1, 5 and 10 mg/kg; 30 min before nicotine), diminishes the effects of nicotine on morphine induced CPP. This result was not observed for the i.c.v and i.p injection of atropine (as muscarinic acethylecholine receptor antagonist). The antagonists themselves, neither showed any motivational effects when used alone nor affected the expression of morphine induced CPP.Conclusion: In conclusion, it appears that central nicotine receptor mechanism(s) may be involved in the expression of the CPP induced by morphine.

Purpose: Diabetic mellitus is regarded as a chronic disease. Nowadays one of the most important methods for the eveluation of treatment and care of this disease is to assess the quality of life. Chronic patients like diabetics are faced with many disorders with regards to the QOL. Therefore the assessment of the QOL and the use of the achieved results are one of the most important treatments goal of NIDDM. In this regard, the researcher tried to identify and compare the NIDDM and the QOL of healthy people.Material and Methods: The research was a comparative descriptive study. The sample consisted of 90 patients with the type 2 diabetes, who were referred to Razi Hospital and 86 health persons as the control group in Rasht city. Subjects aswered to two sets of questions in a questionnaire with one section on the background and demographic characteristics and another section being a standard instrument for the QOL related to health issues which included 7 dimensions of physical function, pain, role function, feeling, sleep status, relation with relative and overall perception of health. The data was analysed by inferential statistics, independent t-test, one way ANOV A and logistic regression.Results: The results showed a significant difference between the QOL and the independent variables of age (P<0.05), job (P<0.002), sex (P<0.001), and education (P<0.00). Comparison of the QOL in the NIDDM patients with that of the healthy persons revealed a significant difference between the QOL dimontions of physical education (P<0.001), pain (P<0.001), and role function (P<.01) between the two groups.Conclusion: In fact, diabetic patients had a notable variation in their QOL dimensions. Therefore, the assessment and measurement of the QOL in chronic patients are very important.

Purpose: Simulation models are unavoidable in experimental research when the point is to develop new processing algorithms to be applied on real signals in order to extract specific parameter values or behaviors. Such algorithms have to be optimized generally by comparing true parameter values to those deduced from the algorithm. Only a simulation model can allow the user to access and control the actual process parameter values. This constraint is especially true when dealing with biomedical signals like surface electromyogram (SEMG) is taken into account.Materials and Methods: This work is an attempt to produce an efficient SEMG simulation model as a help for assessing algorithms related to SEMG features description (such as decomposition algorithm). It takes into account the most important parameters, which could influence these characteristics. Precise propagation and distribution of potential (influences of tissue structure by electrical network parameters in fiber model and nonhomogeneous - anisotropic medium (4 layer) in volume conductor model, Respectively) are considered as such parameters. The effects of electrode configuration, electrode size, inclination of the fiber with respect to the detection system and statistical parameters changes are also included in the model.Results: Using this model we obtain a long term SEMG, which with an additive noise can be used for evaluating decomposition algorithms.

The phenomena of inducing resistance to insecticides by Blattella germanica L. is considered as one of the most important constrains of control measures for this household pest world wide. A lot of research studies have been conducted on the resistance management of B. germanica (L.) to different insecticides. The present investigation was conducted to evaluate the resistant ratios of two strains of B. germanica (L.) at Fatemyyeh Dormitory of Tehran University and Imam- Khomeini Hospital to three insecticides of pirimiphos-methyl, deltamethrin and propoxur.Materials and Methods: The resistance ratio of the two strains at LD50 level were compared with a known susceptible strain.Results and Discussion: The least resistance ratio i.e. negative cross-resistance (0.848), was observed with pirimiphos-methyl applied to the strain at Fatemyyeh Dormitory and the highest resistance ratio (7.123) was observed with deltamethrin applied to the strain at Imam-Khomeini Hospital .The esistance ratio of the strains at Imam-Komeini Hospital and Fatemyyeh Dormitory to propoxur was 1.748 and 1.696 respectively.