Tehran University Medical Journal
Year:2009 | Volume:67 | Issue:7|Papers Count:14

Background: Ample evidence indicated that glucocorticoids, when administered after training, enhance memory consolidation in a variety of tasks. The mechanisms underlying the enhancing effects of glucocorticoids on memory consolidation are not well known. The aim of this study was to determine the role of NMDA receptors and calcium channels in glucocorticoid-induced enhancement of avoidance memory consolidation in mice.Methods: Experiments were performed on 166 male albino mice (about 30gr). The animals were trained in an inhibitory avoidance (IA) task (0.5mA shock for 3 seconds). In Experiment 1, dose- response effects of corticosterone on memory consolidation were determined. Immediately after training in IA task, the animals were received different doses of corticosterone (0.3, 1 or 3mg/kg). In Experiments 2 and 3, effects of corticosterone on memory consolidation were examined in the presence or absence of verapamil, a calcium channel blocker, (2.5, 5 or 20mg/kg) or MK-801, an antagonist of NMDA receptor (0.1mg/kg), respectively. In all experiments, retention test was done two days later.Results: Results from first experiment revealed that corticosterone at dose of 0.3mg/kg significantly improved consolidation of avoidance. Data from experiments 2 and 3 showed that both verapamil, in doses of 2.5 and 5mg/kg, and MK801 significantly blocked corticosterone-induced enhancement of memory consolidation. Conclusion: Finding of this study clearly demonstrated that the memory enhancing effects of corticosterone, at least in part; mediate via calcium channels and NMDA receptors.

Background: The effect of ischemia/reperfusion (I/R) injury on kidney has been under investigation for many years. But the changes in liver function and oxidative stress status in renal I/R injury is not well known. Recent studies suggest a crosstalk between liver and kidneys. The aim of the present study was to assess liver changes after induction of various degrees of renal I/R injury.Methods: This is an experimental study conducted on 20 male rats that were obtained from animal house of Physiology Department. Twenty male rats were subjected to either sham operation or ischemia (30, 45 and 60 min) followed by 60 min reperfusion periods. Blood samples were drawn post-operatively and plasma creatinine, BUN, ALT and AST were measured. Hepatic glutathione (GSH) and FRAP (ferric reducing antioxidant power) levels and the concentration of IL-10 and tumor necrosis factor (TNF) -alpha were evaluated.Results: Both 45 and 60 min ischemia followed by 1h reperfusion periods resulted in significant increases in plasma creatinine (11.1±1.7mg/dl and 1.24±0.07mg/dl vs 0.55±0.15mg/dl, p<0.05) and BUN (34±3.85mg/dl and 35.0±2.81mg/dl vs 23.75±1.1mg/dl, p<0.05). These rats showed a significant decrease in liver GSH as well as significant increase in TNF-a & IL-10 concentrations.Conclusion: Renal ischemia causes changes in liver function and oxidative stress status. A minimum of 45 min ischemia is needed to study the effects of renal injury on liver as a remote affected organ.

Background: Staphylococcus aureus is a major foodborne pathogen throughout the world. Enterotoxins and toxic shock syndrome toxin-1 are important virulence factors and as pyrogenic toxin superantigens have profound effects on the ir host. Thus circulation of TSST1 producing S.aureus among people and food chain is a worrying issue. The present paper was conducted to study Prevalence of tst, entC, entA and entA/C genes in staphylococcus aureus strains isolated from different foods. Methods: Over 1040 food samples have been analyzed differentially according to Iran national standard (number=1194) for S.aureus identification. After DNA extraction, PCR reactions were carried out by reference strain as positive control, adequate primers.Results: At present study, prevalence of foodstuffs contaminated by S.aureus isolates was about 9.5% (100 strains). Of 25% of isolates producing entC, 28% (seven strains) had tst gene at the same time and of 8% of isolates producing entA, 12.5% (one strain) were positive for tst genes simultaneously. Altogether of 9% isolates producing combination of entC and entA, 44.4% (four strains) were also producer of tst gene.Conclusion: Prevalence of TSST1 producing strains in combination with enterotoxin genes is considerable especially with entC and A plus C. On the other hand, circulation of these isolates in humans, animals, foods and environment has hazardous effect for general public health.

Background: CD4 T-Lymphocyte counts have proven to be a standard laboratory marker of disease progression and severity of immunodeficiency in adults infected with HIV is used to initiate and monitor highly active antiretroviral therapy; however, its application may not be feasible for its expensive equipments and reagent in resourcelimited setting. There is a need to have another marker of immunodeficiency that is less resource-demanding. In April 2002, the World Health Organization (WHO) recommended that, when CD4 cell count is not available, a TLC of 1200cell/mm3 or less in individuals with stage 2 or 3 of the disease may be used as an indication to initiate ART.Methods: The aim of this study was to determine the relationship between total lymphocyte count and CD4 count in HIV-infected adults. This was a retrospective cross-sectional study. Subject characteristics were patients who had positive serologic HIV test results, confirmed via western blot. Analysis unit was the results of CBC and CD4 measurements on the same blood sample each time. Data of 100 patients were collected. In this study, TLC accounts for the main predictor of CD4 count. The amounts of TLC which can predict CD4 less than 200cell/mm3 were considered eligible.Results: Our data revealed high sensitivity and specificity of TLC as a surrogate measure of CD4 count. In this study, TLC cutoff of 1300cell/mm3 indicated the optimal combined sensitivity and specificity altogether. Conclusion: Total lymphocyte count and its changes can be used as alternative to CD4 count and its changes in the management of HIV-infected individuals.

Background: Post-intubation tracheal stenosis is a serious problem and surgical resection is the method of choice in long segment tracheal stenosis treatment. The aim of this study was to review the results of surgical treatment of long segment post intubation tracheal stenosis and the role of bilateral hyoid bone cutting in supra- hyoid release technique.Methods: Between 2004 to 2008, 14 patients with proximal long segment tracheal stenosis with resection of more than 40% of trachea length were evaluated regarding surgical technique and post-operative results. Results: The mean age of patients was 22.2±0.4 years. Etiology in all patients were head trauma and prolonged intubation and all patients had tracheostomy at the time of treatment. Average time between surgery and first admission was 4.5±0.5 months. Average length of stenosis and respected segment were 3.6±0.5 and 4.3±0.5cm respectively. Average increased length of trachea after bilateral hyoid bone cutting was 1.1±0.3cm. Postoperative complications occurred in one patient with wound infection, and 4 patients had stenosis recurrence which was treated in 3 patients using multiple dilation. Quality of life 2 years after surgery in 71% of patients were classified in good and excellent group. We didn't have any mortality.Conclusion: Based on the fact that surgery is the best method of treatment in long and multi segment tracheal stenosis and tension in suture line is a serious problem, we recommend extended releasing technique including bilateral hyoid cutting in surgical treatment of these patients.

Background: Standard thoracotomy necessitates division of thoracic large muscles leading to pain and impaired respiratory movements; muscle sparing postero-lateral thoracotomy has been suggested as an alternative to reduce the aforementioned effect. The aim of this study was to compare muscle saving posterolateral thoracotomy with standard thoracotomy.Methods: This study was a clinical trial. All patients who were candidates for elective thoracotomy were included and divided into two groups of muscle saving thoracotomy and standard thoracotomy randomly. Required time for opening and closing the chest, amount of prescribed narcotics, shoulder movements (flexion, extension, abduction and internal rotation), pulmonary function (FVC, FEV1, VC), development of seroma, and duration of hospitalization were assessed. Shoulder movements and pulmonary function were measured immediately before operation and 7 days later while pain measured in 1st and 7th post-operative days. Results: 60 patients (42 males) entered the study and there were no significant differences regarding age and sex distribution between two groups (p>0.05). Mean duration of opening the chest in muscle saving thoracotomy was significantly longer than standard procedure while the duration of closing the chest wall was significantly shorter in muscle saving thoracotomy (p<0.05). FVC and range of motion of the shoulder were higher and post-operative pain was lesser in muscle saving thoraocotomy than standard thoracotomy (p<0.05). There were no significant differences regarding prescribed narcotics and duration of hospital stay (p>0.05). Seroma developed in 13% (n=4) of muscle saving group. Conclusion: Muscle saving thoracotomy can be used as an appropriate alternative for standard postero-lateral thoracotomy in elective thoracic operations.

Background: The mechanisms by which fetal weight are regulated during pregnancy are poorly understood. The relation between hormones such as leptin and adiponectin and intrautrine growth is still under investigation. The aim of this study was to ascertain whether fetal growth restriction is associated with alterations of leptin and adiponectin concentrations in venous umbilical cord blood and maternal serum. Methods: Maternal serum and venous umbilical cord blood leptin and adiponectin concentrations were determined by ELISA after 36 week of gestational age in 22 women with uncomplicated singleton pregnancies with AGA fetuses (group A) and in 22 women with singleton pregnancies complicated by fetal growth restriction but without fetal distress (group B), all with normal body mass index and without history of diabetes, hypertention or maternal cardiac disease. Results: Venous umbilical cord leptin levels were significantly lower in group B compared with group A (8.1±0.8ng/ml versus 39.45±6.8ng/ml; p=0.001). Venous umbilical cord adiponectin levels were also significantly lower in group B compared with group A (28.8±3.5mg/ml versus 43.6±3.7mg/ml; p=0.007). Maternal serum leptin and adiponectin did not differ between SGA and AGA groups.maternal BMI, gestational age and maternal age did not differ between these two groups. Neither leptin nor adiponectin correlated with gender difference. Conclusion: In this study we confirmed that growth restricted fetuses show venous umbilical cord blood leptin and adiponectin concentrations were significantly lower than those in normal fetuses indicating that these two adipokines have an independent role in growth restriction pathogenesis. Maybe in future we can administer recombinant human leptin and adiponectin to growth restricted fetuses for treatment.

Background: Neck lymph node metastasis has the prognostic role in SCC of the tongue and the importance of the biologic markers in tumor invasion and metastasis has been stated in the medical literature. The aim of this study was to evaluate the relationship between two biomarkers, p53 and EGFR (which had the main role in cell proliferation) and two other biomarkers, CD44 and E-cadherin, in lymph node metastasis. Methods: In an analytic descriptive study fifty three patients with SCC (Squamous Cell Carcinoma) of the tongue who underwent the resection of tumor and dissection of neck lymph nodes were assessed during the year of 2002-2009. Histological samples from 53 patients were immunohistochemically stained and the analysis of these markers were performed due to clinicopathological variable and metastasis of the neck lymph nodes. Results: The result showed that among the clinicopathological factors, the relationship between Age (p=0.01), history of having risk factors (p=0.002), clinical lymphadenopathy (p=0.002), the size of the tumor (p=0.001), decreasing of CD44 (p=0.02) and lymph node metastasis of the neck were statistically significant. No significant relationship were found between sex and other biomarkers including p53, EGFR, E-cadherin.Conclusion: CD44 is an important indicator of prognostic markers that can also be used as an indicator of clinocopathological markers.

Background: Flexor tendon injury is one of the unanswered problems in reconstructive surgery of the hand. Although pull out method is one of the best reconstructive approaches but still is controversial. Surgeons prefer immobilization to prevent laceration at the site of the suture but it may cause adhesion and lead to surgical failure. The aim of this study was to perform a new surgical method to achieve a tendon repair without these problems.Methods: In this case-series study, 80 fingers with flexor tendon impairment selected and divided into four groups (tendon laceration & avulsion, tendon graft reconstructed in 1 & 2 stages) then patients were surgically treated by the new technique. The most important aspect of the technique is the placement of the suture in the direction of strength therefore, following any tension the suture would be tighter and this point help us to mobilize the injured tendon immediately after the surgery then we analyzed the results depends on the patient’s group.Results: The pull out and surgical (functional) results were evaluated. 97% of the pull out results were good and 3% were poor and surgical results were 23.9% excellent, 52.2% good, 17.9% fair and 6% poor. Conclusion: Depend on the acceptable results, immobilization in these patients is unnecessary & active and passive range of motion would be gradually increased as soon as possible. However biomechanical studies would be beneficial to evaluate this suture influence and designing future studies to compare this technique with old methods would be essential.

Background: Detection rate of Ductal Carcinoma Insitu of the breast (DCIS) have increased rapidly over the past decade, which is generally attributed to the widespread use of screening mammography. The aim of this study was to evaluate the prevalence of ductal carcinoma in situ in patients who had been referred to Tehran university medical centers.Methods: In a retrospective study, medical records of the patients with diagnosis of breast cancer in 3 teaching hospitals of Tehran University of Medical Sciences (Cancer Institute, Sina and Shariati Hospitals between 1994-2003) were reviewed and records with ductal carcinoma in situ were selected and analyzed. Results: Between 2244 medical records of breast cancer 23 patients had DCIS (1.02%). Mean age was 47.3 years just one patient had been detected by screening mammography and others had clinical symptoms. 48% of patients had mass with mean size of 3.3cm. All had undergone open biopsy (four incisional, 19 excisional). Treatment included 65.2% modified radical mastectomy, 30.4% lumpectomy with axillary dissections and 3.8% lumpectomy alone. Nine patients had radiotherapy after surgery and ten took tamoxifen as hormonal therapy. Two patients (8.6%) in lumpectomy group had recurrence in follow ups. Median follow up time was 84 months.Conclusion: This study shows that the Prevalence of early stages of breast cancer especially ductal carcinoma in situ is extremely low. (DCIS was 1.02 in comparison with 15-30% in western countries). These findings indicate the need for increasing public information about breast cancer in Iran and improving screening programs of breast cancer.

Background: Coronary artery anomalies may be seen in 1-5% of coronary angiographies. Origin of the left coronary artery from right aortic cusp is a very rare anomaly and its incidence is about 0.15%. This anomaly could be presented by myocardial ischemia and even sudden cardiac death during exercise in young patients. For the diagnosis of coronary anomalies different diagnostic modalities such as, echocardiography, angiography and CT angiography can be helpful.Cases: We report 3 cases with this anomaly and two of them did not have any lesion in their coronary arteries One of these patients had severe coronary artery disease and underwent coronary artery bypass graft surgery. Conclusion: Although abnormal origin of left coronary artery from right aortic valsalva sinus is a rare anomaly, due to causing ischemic cardiac symptoms and the possibility of sudden cardiac death it is considered an important anomaly. For definite diagnosis of this anomaly coronary angiography and/or CT angiography is useful.