Tehran University Medical Journal
Year:2006 | Volume:64 | Issue:6|Papers Count:17

MicroRNAs form a class of small non-coding RNA molecules. With only 21-23 nucleutide in length, they have an important role in gene expression. These molecules bind to their target mRNA molecules and repress the protein expression via mRNA degradation or blocking the translation machine of the cell. From the advent of molecular biology microRNA molecules were out of focus, however huge amount of studies in the past few years revealed a lot of facts about their nature. Nowadays around 1600 different microRNA are discovered in human, animals, plant and even viruses. In this review article the most recent data in the history, genes, expression and process of these molecules are introduced. Furthermore, the findings about diverse roles of these molecules in normal and abnormal conditions, cancer in particular, are shown. Finally, the differences to siRNA molecules and the prospect of microRNA have been explained.

Background: Staphylococcus aureus and Staphylococcus epidermidis are major human pathogens of increasing importance due to the spread of antibiotic resistance. Novel potential targets for therapeutic antibodies are products of staphylococcal genes expressed during human infection. Previously, the secreted and surface-exposed proteins among seroreactive antigens have been discovered. Furthermore, approximately 60 immunogenic proteins were identified and have shown that bacterial surface display is uniquely suited to assess the value of the antigenic epitope. Methods: Using a bioinformatic analysis, a novel gene family was identified in Staphylococcus aureus and S. epidermidis. NCBI (National Center for Biotechnology Information) BLAST and TIGR search were used for identification of the loci on Staphylococcal genomes.Results: The members of nine gene family from S. aureus based on a conserved Cterminal domain following an N-terminal domain which varies in sequence and length.Further Blast P searches for paralogues revealed the novel Sca gene family in S.epidermidis has also highly conserved 110 amino acid C-terminal domain. Thus the Sca family has a conserved domain across different genera. Conclusion: Further studies to determine the role of the conserved Sca domain in ligand binding and demonstration of conserved epitope may establish the domain as a credible target for cross species vaccination.

Background: Hyaluronan has an important role on the permeability and motility of sperm and the interaction of gametes and these can play a considerable role on the fertility rate. Therefore, in this study, we assessed the effect of different doses of hyaluronan on the morphology, motility, vitality and fertility rate of mice.Methods: We used 40 mice (6-8 week) in this study which twenty of them were male and the rest were female. The sperm of each male mouse were divided into four groups.The group 1 (control): They were maintained in RPMI media without any hyaluronan supplementation for 2 hour. Hyaluronan with the doses of 750, 1000 and 1250 mg/ml were added into RPMI media in groups 2, 3 and 4, respectively. After 2 hour.incubation, the numbers of sperms were assessed, using haemocytometer. Also, their morphology with papanicolaeu staining and their vitality with Eosin B dye were assessed. As well as sperms motility measured under inverted microscope by observation and fertility rate evaluated after routine IVF by counting two-cell stage embryos.Results: Our results demonstrated that, the dose of 750 mg/ml has the greatest effect on the motility, vitality and fertility rate of sperms. The effect of dose of 1000 M g/ml also was positive on them. On the other hand, none of these doses had any effect on sperm morphology.Conclusion: Hyaluronan may have an influence on motility, vitality and fertility rate of sperms and the dose of 750m g/ml had a significant effect on these factors.

Background: Diabetes mellitus is a chronic disease that is associated with numerous complications like peripheral neuropathies. It has been shown that hyperglycemia may contribute to its development but the exact pathophysiology underlying this complication has not been fully understood. Since it has been suggested that oral magnesium supplementation can prevent hyperglycemia induced by diabetes, this study was designed to examine the protective effect of oral magnesium administration on thermal hyperalgesia in streptozocin (STZ) induced diabetic rats. Methods: Male adult wistar rats were divided equally into control, magnesium-treated control, diabetic and magnesium-treated diabetic groups. In magnesium-treated diabetic rats, magnesium sulfate (10 gr/L) was added into drinking water since diabetes was established (10 days after STZ injection) and continued for 8 weeks. Mg-treated control animals received magnesium sulfate in the same dose and time period. The other two groups; control and diabetic animals, only received tap water.Results: A significant decrease in thermal pain threshold and plasma magnesium levels and also a dramatic increase in plasma glucose levels were seen in diabetic rats eight weeks after diabetes induction. Eight weeks magnesium therapy after the diagnosis of diabetes, could prevent reduction in thermal pain threshold and also restore plasma magnesium and glucose levels in magnesium-treated diabetic animals.Conclusion: Oral magnesium can prevent hypomagnesaemia, hyperglycemia and thermal hyperalgesia in diabetic rats.

Background: The aim of this study was to determine the level of lipid peroxidation and tissue protein after superior mesenteric artery occlusion tissue damage. The effect of melatonin as anti oxidant and free radical scavenger in prevention of tissue damage, were also evaluated.Methods: Thity six young male Wisatr-Albino rats (weight: 80-120 gr), were divided equally in 6 group with different concentrations of melatonin (10, 20, 30 mg/kg) treatment. Group Iwas control, group 2 the sham that surgical process was applieduntil superior mesenteric artery dissection and received vehicle solution only in equally volume by intra muscular route. Group 3 was ischemia- reperfusion (I/R), group 4 was I/R plus melatonin 10 mg/kg, group 5 I/R plus melatonin 20 mg/kg and finallygroup6 I/R plus melatonin 30 mg/kg. After laparatomy, a microvascular atraumatic clip was placed across the superior mesenteric artery under general anaesthesia and it removed after ischemia for 30 minutes. The first dose of melatonin was applied just before reperfusion, second dose, after reperfusion and third dose on the secondday. On third day rats were killed and their bowels were removed. The level of tissue melandialdehyde (MDA) as index of lipid peroxidation and tissue protein was determined.Results: The level of tissue MDA were significantly lower in group 4, 5, 6 than group 3 (p<0.05). Tissue protein levels were significantly upper in group 4 than group 3. (p<0.001). There was no significant difference tissue protein level in group 5, 6 than group 3( p>0, 05).Conclusion: These results suggest that melatonin 10 mg/kg has antioxidant effecting prevention of inducing tissue damage during SMA occlusion in rat intestine.

Background: To evaluate long-term outcome and satisfaction of MacIndo surgery with and without amnion graft.Methods: This is a historical cohort study of patients who were treated with the McIndo procedure for vaginal agenesis. Participants answered a structured questionnaire to describe outcome in sexual function and satisfaction. Patient characteristics along with short and long-term endings were abstracted from the medical records.Results: Thirty-five patients responded to the questionnaire. Average age (±SD) at surgery was 28.4±3 years (range 17- 48 years). The mean number of years (±SD) since surgery was 7 years (range 2-12 years). In 15 patients (42.8%) amniotic graft were amniotic graft were used only in is patients (42.8%). There was no relation between two types of surgery (long-term outcome and satisfaction with p-values of 0.346 and 0.758 respectively).Conclusions: Since there was not a statistical difference between these two types of McIndo methods, it is recommended to apply the procedure in which amnion is not used. This procedure (without amnion graft), is an easier method with less operation time and reduced viral (HIV…) transmission.

Background: This study was designed to investigate the process of bone formation caused by implantation of octa calcium phosphate (OCP) in rat tibiae.Methods: We used 25 young male Sprague-Dawley rats. A full thickness standardized trephine defect, 3-mm in diameter, was surgically created on the superior end of right and left tibia. Amount of 6-mg synthetic Octa calcium Phosphate was implanted into a bony defect on the right tibia as a experimental group. No OCP particles were implanted in the left tibia as a control group that was otherwise treated identically.Bone formation was examined histologically on 7th, 10th, 14th, 21st, 28th days after implantation.Results: In the experimental group, on the 7th day after implantation, a few clusters of cartilage cells were observed between the OCP particles near the defects margin.Osteogenesis was initiated locally between the OCP particles in central position of the defects on 10th day after implantation. By 14th day after implantation, Alcian blue staining showed hypertrophic chondrocytes that replaced by new bone. In addition to bone formation locally around the OCP particles, more apposition of new bone was observed near the defects margin on 14th and 21st days after implantation. At the end of study implanted OCP was surrounded by newly formed bone. In the control group, at the end of study, bone formation was observed only along and near the defects margin.Conclusion: These results demonstrate that octa calcium phosphate could be used in the repair of the long bone defects.

Background: In the year 2003, an earthquake in Bam led to death and injury of many of the inhabitants. The aim of this study was to the changes in opioid drug use in the survivers eight months after the earthquake in comparison with the month before the quake and its related factors.Methods: An epidemiologic survey was carried out on 779 survivors, selected by desert sampling from the Bam citizens in the age of 15 and over. Bivariate and multivariate Logestic regression analysis were done for examining the relationship between an increase in opioid use and various factors.Results: An increase in opioid use was reported in 18.3 percent of men and 2.3 percent of women. Odds Ratio (OR) for increase in opioid use was 9.4 times more in men than in women (95% CI=4.9-18.0). In men, increase in opioid use was related with the history of opioid use during the month before earthquake (OR=5.6, 95% CI=2.4-13.1), age (OR in age group 30 to 44 was 4.7 times more than age below 30, with 95% Cl from 1.8 to12.1), and PTSD (OR=3.7, 95% CI=1.5-9.2). In women, it was only related to the history of opioid use during the month before earthquake (OR=43.8, 95% CI=12.5-154.0).Conclusion: The findings show that following disasters, especially in the areas or groups that drug use is common, an increase in the drug use might occur. In these situations provision of preventive and treatment interventions particularly for at risk population is necessary.

Background: The aim of this study was to evaluate the mechanical and infectious complications of continuous ambulatory peritoneal dialysis catheter in surgical wards of Imam Khomeini Hospital.Methods: We retrospectively reviewed 80 catheters that were inserted into 69 patients (52 men and 28 women) with end-stage chronic renal failure during a period of 84 months (13 Nov. 1996 to 13 Nov. 2003).Results: The mean age of patients was 48:35 years (16 to 79 years). The most common complications were infectious ones (71.25%), while the most common causes of the catheter removal were mechanical ones (46.5% vs. 39.55%. The predominate cause of the mechanical complications was improper position (17.5%). Migration of catheter to upper abdomen and outflow failure were the other common mechanical complications. The most common infectious complication was peritonitis (62.5%). Conclusions: The occurrence of the mechanical complications is lower than the infectious ones, but the probability of catheter loss is higher if it occurs.

Background: Hypertention and diabetes are important risk factors for cardiovascular disease. studies have shown that microalbuminuria is a strong predictor of cardiovascular disease in different population. In this study the relation of microalbuminuria with diabetes and hypertention as risk factors of atherosclerosis disease were investigated.Methods: Two hundered twenty eight patients with angiographically confirmed coronary atherosclerotic lesions, (mean age 60 ± 0.5 SD) referred to Madani Hospital, Tabriz, Iran were studied .This patients according to the number of diseased vessels were classified in two groups. The levels of glucose and creatinine and that of post parandial glucose were determined in venous blood samples by standard methods. Immunoturbidimetric method was employed in the measurement of microalbuminuria. The results were analysed by statistical tests.Results: The increased albumin/creatinine ratio was markedly correlated with fasting blood sugar, systolic and diastolic blood pressure (P < 0.05 in all cases). Significant correlation was noticed between microalbuminuria, diabetes according to the extension of the disease lesions (P < 0.05). No relationship was observed between microalbuminuria, high levels of blood pressure according to the number of diseased vessels (P > 0.05).Conclusion: The relationship between diabetes and microalbuminuria was meaningful. According to atherosclerotic lesions a marked correlation was also noticed between microalbuminuria and diabetes. These facts may contribute to the higher cardiovascular risk in diabetic patients. An associated between hypertension and microalbuminuria was noticed. The result suggests that although risk factors such as hypertension and diabetes are known to cause cardiovascular disease, microalbuminuria may in fact be a better indicator of established microvascular damage and better predictor of cardiovascular events.

Background: Cerebral palsy is the term used to describe a movement disorder though to be the result of no progressive brain damage. Due to damage to CNS, it is associated with articulation disorder and abnormal feeding reflex. Lack of oral function control and coordination following feeding reflex disorders. Articulation disorders are seen in most of the cerebral palsied patients. This research aimed to determine the relationship between feeding reflexes and articulation in cerebral palsy (spasticchildren).Methods: This study was cross sectionally carried out on 52 children with cerebral palsy, 5 to 10 yrs old, in rehabilitation centers and private clinics. The information related to feeding reflexes was collected through direct observation of patient and evaluation of sound articulation through phonetic information test.Results: Statistical analysis carried out by SPSS and chi-square and fisher exact tests. Abnormal chewing and tongue reflex are more prevalent than other feeding reflexes. The relationship between lip reflex and articulation of p/m/r/y/f/_ and chewing reflex with articulation of/z/ Š / is meaningful. The relationship between biting reflex with articulation of /z/j/l/Š/ is meaningful. The relationship between tongue reflex and rooting reflex with articulation of sound is not meaningful.Conclusion: With regard to the result of this research, it can be suggested that in children with cerebral palsy following feeding reflex disorders, abnormal posture during speech occurs that could have effect on articulation.

Background: Calcium-antagonists (CA) are heterogeneous group of drugs with different efficacy in migraine prophylaxis. Several studies have firmly demonstrated flunarizine (FLU), and verapamil as the proven calcium-antagonists for migraine prophylaxis. Cinnarizine (CIN), is another CA with less complications and less antihistaminic action. There is very few studies to show the effect of this drug on migraine. The current study evaluates the efficacy and safety of cinnarizine on migraine in comparison to sodium valproate, an acceptable drug in migraine prophylaxis.Methods: The current study is a randomized double blind clinical trial on 133 participants with intractable migraine headache to evaluate the positive effect of cinnarizine in comparison to sodium valproate. The data was collected and analized by SPSS software.Results: The mean age of cases was 34.3±10 years in Cinnarizine group and 33.4±11 in Sodium Valproate users. The headache frequency decreased to about 50% and its severity to about 30% in both groups. Although the effect of Cinnarizine was started earlier than sodium valproate, there was no significant difference between two groups of cases in improvement of headache attacks. Statistically significant difference was noted in drug’s complication led to discontinuation of treatment, 5.2% in Cinnarizine users in respect to 14% in valproate group.Conclusion: The patients who received Cinnarizine, similar to the patients on sodium valprote showed significant improvement in headache attacks, frequency, duration and severity. Cinnarizine such as sodium valproate is an effective drug in migraine prophylaxis even in intractable headache, but with lesser severe complication.

Background: percutaneous dilatational tracheostomy was invented by ciaglia in 1985. With advent of various instruments, various methods such as Fantoni, Grigges and etc, it became a widesepreadly used method of tracheostomy, especially in intensive care unit wards. In our country this was began in 2005, along with many work shops conducted by anesthesiology department of Tehran University of Medical sciences, with help of specialist from Turin University from ITALY.Case report: In this report two patients who underwent percutaneous dilatational tracheostomy are presented, and are compared with patients who had undergo surgical tracheostomy. Their long and short term complications such as bleeding, injury extents, and recovery was studied and presented.Conclusion: Tracheostomy is an opening in front of neck, in to the trachea, through which breathing is made possible. Percutaneous Dilatational Ttracheostomy (PDT) is a method of tracheostomy, in which the need for surgery and transfer of patient to operation room is alleviated. Dispite various benefits, PDT has a few short term and long term drawbacks, which are cartilage fracture, injury to vital structures, perforation of posterior wall, sever bleeding displacement of tube, tracheo-esophageal fistula and trache-oinnominate fistula. Incidence of these complications is lower than surgical tracheostomy. Global reports, especialllly from countries with large scale experiences present a different statistic regarding its success as an alternative method for patients with long surveillance and under mechanical ventilation.