مجله پزشکی کوثر
سال شانزدهم شماره 1 (پیاپی 59، بهار 1390)

Shigellosis is caused by Shigella species. Considering the high frequency of morbidity and mortality reports and antibiotics resistance, designing and producing a vaccine against this disease is one of the goals of World Health Organization. Invasion Plasmid Antigen especially IpaC and IpaB are the major Shigella virulence agents and are also vaccine candidates. The aim of this study was to express ipaC gene which is of the virulence factors in order to investigate its immunogenicity. In this study, ipa C gene was obtained from NCBI gene bank and primers were designed. After genome extraction from Shigella dysenteriae, it was used as template for PCR amplification. The amplified ipa C gene by PCR was cloned into pTZ57R and sub-cloned into the expression vector pET-28a(+). E. coli BL21(DE3)plysS was transformed by recombinant vector pET-28a(+)/ ipa C and expression of the recombinant ipa C was investigated by IPTG induction and SDS-PAGE electrophoresis. Cloning was confirmed by PCR, enzyme digestion and sequencing. In addition, the recombinant protein was expressed by IPTG induction. Protein expression was confirmed by Ni–NTA column, Western-Blotting analysis and SDS-PAGE electrophoresis. Cloning, sub-cloning and expression of ipaC gene are confirmed in the present study. Therefore, this recombinant protein can be used for production of a recombinant vaccine against Shigella dysenteriae in future studies, after immunogenicity assay.

Studies have revealed the effect of nitric oxide on different types of memory and learning and also the interaction between the nicotinic system and opioids. In the present study, the effect of pre-test injection of nicotine on morphine state dependent learning and the effect of intra-NA administration of the nitric oxide on nicotine’s effects in morphine state-dependent learning were investigated. This experimental study was performed on 230 Wistar rats. Rats were anesthetized and then placed in a stereotaxic apparatus. Two cannulas were placed 2 mm above nucleus accumbens shell. A one week gap was considered before beginning of behavioral test. Animals were trained in an inhibitory avoidance task. The drugs were injected after training. The step-through latency was considered as the criterion for the assessment of memory. Data was analyzed by one and two-way variance analysis and Tukey's test using SPSS 17. Post-training injection of morphine induced amnesia (p<0.001) and the amnesia restored with pre-test administration of same doses of morphine. Pre-test injection of nicotine had no effect on inhibitory avoidance memory retrieval, but restored the amnesia. Co-administration of ineffective dose of morphine with different doses of nicotine synergically restored morphine amnesia. Pre-test injection of L-arginine that had no effect (p>0.05) prevented the nicotine reversal effect on memory. Nicotinic acetylcholine and nitric oxide system may be involved in morphine state dependent learning. In addition, L-arginine can inhibit the improving effect of nicotine on morphine-induced amnesia.

Nicotine can affect anxious behaviors through its direct effect on presynaptic nicotinic receptors. In addition, dorsal hippocampus and D2 dopamine receptors play modulatory role in anxiety behavior, based on previous studies. This study was performed with the aim of evaluating the role of dopaminergic D2 receptors of dorsal hippocampus on anxiety behavior induced by nicotine, in mice. In this experimental study, male laboratory mice were anesthetized with intra-peritoneal injection of ketamine hydrochloride plus xylazine and then were placed in a stereotaxic apparatus. Two stainless-steel cannulas were placed in dorsal hippocampus. All animals were allowed to recover for one week before behavioral tests. The hole-board test was performed for evaluating anxiety-like behaviors. Data was analyzed using one-way analyses of variance followed by Dunnett’s test, using SPSS 17 software. Intra-peritoneal injection of nicotine decreased number of head-dip (p<0.001) but had no effect on locomotion activity (p>0.05) which showed the anxiogenic effect of nicotine. The bilateral intra-dorsal hippocampal injections of ineffective doses sulpiride reversed anxiogenic response induced by nicotine (p<0.01) without affecting locomotion activity (p>0.05). Furthermore, co-administration of ineffective dose of quipirole plus ineffective dose of nicotine increased anxiogenic effects of nicotine (p<0.001) but had no effect on locomotion activity (p>0.05). It seems that dopaminergic D2 receptors of dorsal hippocampus play modulatory role in anxiogenic response induced by nicotine.

Methicillin Resistant Staphylococcus aureus is among common pathogens that its prevalence has increased all around the world during past three decades. Staphylococcal Enterotoxin B (SEB) is one of the most important Staphylococcal enterotoxins, which is considered as an important pathogenic factor. The aim of this study was investigating the correlation between SEB and resistance to Methicillin. This cross-sectional study was performed on inpatients of one of the hospitals of Tehran in year 2008 who were selected by accessible sampling method. Correlation between SEB gene in Methicillin Resistant strains was investigated in 100 samples isolated from wounds. Antibiogram was done by disc diffusion and presence of SEB gene was confirmed by PCR. Data was analyzed by SPSS 17 software using descriptive statistical methods and Chi square test. Only 8% of strains had SEB gene. 75% of Staphylococcus aureus strains that had SEB gene were Methicillin resistant and only 15% of them were Methicillin sensitive. A significant correlation was observed between the SEB gene and Methicillin resistance (p<0.05). There is e significant correlation between presence of SEB gene and Methicillin resistance and this issue can reinforce the hypothesis that SEB gene has role in Methicillin resistance.

Rate of wound closure signifies the quantity and rate of wound maturation represents the quality of healing. The rate of wound closure is commonly evaluated by measuring the wound area and its maturation is evaluated by physical examinations. The aim of this study was to propose an accurate and sensitive semi-quantitative method for evaluation of quality and quantity of the wound healing in full thickness skin wounds of laboratory models.

20 white adult male rats were used in this experimental study. Full thickness wounds were generated on the back of rats and were evaluated after twelve days. In macroscopic study wound closure was determined by measuring the wound area using ScnImage software after photographing. The healing quality was evaluated by monitoring skin erythema and inflammation. In microscopic study wounds were harvested, fixed, processed and then stained with H&E. Wound closure was determined by microscopic examination of sections and maturation indices including inflammation, vascularity and cellularity were also determined.

By macroscopic examination 21.7% of wounds were close and 78.3% were open. Microscopic evaluation revealed that 40% of wounds were open and 60% were close. The scab on the wound surface was the reason for this significant difference (p<0.05). Microscopic examination revealed that maturation indices were different in the margin and center of wounds. These parameters could not be measured by macroscopic methods.

Macroscopic methods have considerable errors in evaluation of healing. Therefore, microscopic methods should be used in basic studies and evaluating the drug effects.

Uncontrolled salt intake may increase arterial blood pressure. In many patients, high blood pressure is associated with big arterial wall injuries. This study was performed with the aim of evaluating the probable changes of arterial wall in laboratory mice after a period of oral salt intake. In this experimental study, 20 male and 20 female laboratory mice weighing 30-35 grams with 2 months of age and Balb/c ethnicity were randomly divided into two experimental and control groups. There were 10 male and 10 female mice in each group. The experimental group received normal saline as 18 gram NaCl solved in 1000 cc tap water for 12 weeks and the control group received tap water in the same period. All mice were anesthetized by chloroform and killed and the aorta and carotid arteries were excised and placed in 10% formalin solution for fixation. Sections were obtained from the paraffinized blocks and stained by Hematoxylin & Eosin. Stained sections were observed microscopically. Elective specimens were photographed and findings were statistically analyzed. Atheromas were observed in big arterie's intima in experimental mice but this phenomenon was not seen in control group. Cholesterol deposition and vacuolated macrophage infiltration were other abnormal changes in arterial wall of mice in experimental group that did not exist in control group (p<0.001). Abnormal changes in the experimental group which are mentioned above indicate atherosclerosis in these laboratory models. Therefore, probably high salt intake induces atherosclerosis.

Gastric cancer is one of the most common cancers in Iran and is one of the most frequent causes of death due to cancer. Despite progresses in treatment, it still causes much mortalities and its treatment is still a matter of debate in the world. This study was performed with the aim of investigating the factors affecting prognosis, the survival rate and effect of different treatments on survival in gastric adenocarcinoma patients. This analytical case series study was conducted on 47 gastric or cardia adenocarcinoma patient referring to Shahid-Ramezanzadeh Radiation Center from 2004 to 2009 and were selected by accessible sampling. Data was extracted from patient's records and follow up was conducted through telephone contacts. Kaplan-Meier curves and SPSS 13 software were used for data analysis. Two-year and three-year survival of patients were 50% and 30%, respectively. Mean survival rate was 29.9 months and mean disease free survival rate was 12.95 months. Survival rate revealed a significant relation with disease stage (p=0.046), performed therapies (p=0.027) and surgical margin. Patients who had received a combination of surgery, chemotherapy and radiation therapy had the best survival. Survival had no relation with type of adenocarcinoma, tumor location or grade and chemotherapy regimen. Age, gender, surgery type, tumor location or grade and chemotherapy regimen do not affect survival, but the disease stage, performed therapies and surgical margin affect it. It seems that a combination of surgery, chemotherapy and radiation therapy would provide the best effect on patent's survival.

Due to increase of heart failure among athletics, biochemical and immunological investigations have indicated cardiac dysfunction and damage with changes in cardiac markers and inflammatory cytokine response after endurance exercises. Therefore, investigating the physiology and cardiac pathophysiology can help in providing a proper background for identifying the endangered athletes. This study was performed with the aim of investigating the effect of endurance exercises on cardiac markers and the inflammatory response in elite kayakers. This quasi-experimental study was performed in year 2007 on all national team male kayakers of Iran with age of 22/5±3/2 years, weight of 78/7±7/2 kilograms and height of 184± 4 cm, who were selected by random sampling method. Participants kayaked 8000 meters with 75-80% of maximal heart rate for 60 minutes. Blood samples were taken before, immediately after and three hours after the exercise in order to assess the levels of plasma NT-proBNP and IL-6. Data was analyzed by SPSS 16 using variance analysis with repeated measures and paired t-test. NT-proBNP levels significantly increased (24/05±9/6 vs 19/36±7/5 pg/ml; p<0/001), while the plasma IL-6 insignificantly decreased (0/755±0/29 to 0/715±0/19 pg/ml; p=0/91) in response to prolonged endurance kayaking. There was no correlation between IL-6 and NT-proBNP levels after exercise. Exercise-induced increase in NT-proBNP may represent physiologic reaction under special exercise conditions and seems to have no significant pathological importance. The insignificant decrease in plasma IL-6 provides no evidence of myocardial damage.

Leptin is a peptide hormone which is basically secreted by adipose tissue and regulates the energy metabolism and balance and therefore controls the body weight. Effect of long term exercise on serum leptin levels is unclear. This research was performed in order to investigate the effect of six months aerobic exercise on serum leptin, cortisol, insulin and glucose levels in middle-aged women. This quasi-experimental study was performed in year 2009 on 19 healthy middle-aged women who were selected by accidental sampling method. Subjects were randomly divided into two experimental (11 subjects) and control (8 subjects) groups. The Exercise protocol included aerobic exercise for 6 months and 3 sessions per week and every session lasted 60 minutes with intensity of 60-70% of heart rate reserve. Data was analyzed by SPSS 16 software using descriptive and inferential statistical methods including independent t-test for investigation of inter-group changes. Mean of variables did not change significantly from pre-test to post-test in two experimental and control groups. Six months of aerobic exercise did not induce significant change in individual's weight and body mass index and serum levels of leptin, cortisol, insulin and glucose. Six months of aerobic exercise does not induce significant change in serum levels of leptin, cortisol, insulin and glucose in thin middle-aged women. Regular physical activity probably causes decrease in serum leptin level if body mass index and body fat mass reduce simultaneously.

Leptin is an adipose tissue related hormone that contributes to food intake control, energy expenditure and other activities such as cell proliferation. Relationship of Leptin level with hypothyroidism, hyperthyroidism and thyroid cancer has been suggested recently. As thyroid cancer is the most common endocrine cancer, the aim of this study was evaluation of Leptin levels in thyroid cancer patients. In this descriptive-sectional study, 83 patients with papillary thyroid cancer (35 males and 48 females) and 90 healthy persons (40 male and 50 females) were selected by purposeful sampling method from April 2009 to April 2010. Serum Thyroxine, Thyrotropin and Leptin levels were determined in both groups. As body fat tissue affect Leptin level, height and weight and body mass index was measured. Independent T-test was used for comparing parameters and SPSS 15 software was used for data analysis. There was no statistically significant difference in age average and serum Thyroxine and Thyrotropin levels. BMI was higher in women than men in both groups. Serum Leptin level in thyroid cancer group (women 23.3±19.6; men 17.3±10.4 ng/ml) was significantly (p<0.05) higher than control group (women 6.9±4.3; men 5.6±2.2 ng/ml). Leptin level has relation with papillary thyroid cancer. Probably, Leptin level can be consider as a help marker in diagnosis or confirmation of thyroid cancer.