مجله دانشکده پزشکی دانشگاه علوم پزشکی تهران
سال شصت و پنجم شماره 12 (پیاپی 84، اسفند 1386)

Relaxation of the corpus cavernosum plays a major role in penile erection. Nitric oxide (NO) is known to be the most important factor mediating relaxation of corpus cavernosum, which is mainly derived from nonadrenergic noncholinergic (NANC) nerves. The aim of the present study was to investigate the effect of biliary cirrhosis on nonadrenergic noncholinergic (NANC)-mediated relaxation of rat corpus cavernosum as well as the possible relevant roles of endocannabinoid and nitric oxide systems. Corporal strips from sham-operated and biliary cirrhotic rats were mounted under tension in a standard oxygenated organ bath with guanethidine sulfate (5 µM) and atropine (1 µM) to induce adrenergic and cholinergic blockade. The strips were precontracted with phenylephrine hydrochloride (7.5 µM) and electrical field stimulation was applied at different frequencies (2, 5, 10, 15 Hz) to obtain NANC-mediated relaxation. In separate precontracted strips of the sham and cirrhotic groups, the concentration-dependent relaxant responses to sodium nitroprusside (10 nM-1mM), as an NO donor, were assessed. The NANC-mediated relaxation was significantly enhanced in cirrhotic animals (P<0.01). Anandamide potentiated the relaxations in both groups (P<0.05). The cannabinoid CB1 receptor antagonist AM251 (10 µM) and the vanilloid receptor antagonist capsazepine (10 µM) each significantly prevented the enhanced relaxations in cirrhotic rats (P<0.01). The CB2 receptor antagonist AM630 had no effect on relaxations in the cirrhotic group. In a concentration-dependent manner, L-NAME (30-1000 nM) inhibited relaxations in both the sham and cirrhotic groups, although cirrhotic groups were more resistant to the inhibitory effects of L-NAME. The degree of relaxation induced by sodium nitroprusside (10 nM-1 mM) was similar in the two groups. Biliary cirrhosis enhances the neurogenic relaxation in rat corpus cavernosum probably via the NO pathway and cannabinoid CB1 and vanilloid VR1 receptors.

Ultrasound (US) has been used in neuroprotection after cerebral ischemia, however the mechanism of action remains unclearly. We have previously shown the protective effect of ultrasound on infarction volume and brain edema in ischemic brain injured at normothermic condition. Ultrasound may also amplify the effect of fibrinolytic medications in thrombolysis process. We have also shown that hyperthermia can exacerbate cerebral ischemic injury and that the efficacy of tissue plasminogen activator (tPA) is reduced in the presence of hyperthermia. In this study, the effects of US alone or in combination with tPA on brain ischemic injury were evaluated.

Focal ischemic brain injury was induced by emblazing a pre-formed clot into the middle cerebral artery in rats. Principally, we examined whether US can reduce the perfusion deficits and, the damage of blood- brain barrier (BBB) in the ischemic injured brain. There are two series of experiments at this study. in the first series, animals were randomly assigned to four groups (n=7 per group) as follows: 1-control (saline), 2-US (1W/cm2, 10 duty cycle), 3- US+high- tPA (1W/cm2, 10 duty cycle +20 mg/kg) and 4- high -tPA (20 mg/kg). We also examined the effects of US and tPA on BBB integrity after ischemic injury. The animals were assigned into four groups (n=7 per group), treatment is the same as above. BBB permeability was assessed by the Evans blue (EB) extravasations method at 8 h after MCA occlusion. BBB permeability was evaluated by fluorescent detection of extravagated Evans blue dye and Perfusion deficits were analyzed using an Evans blue staining procedure. The perfused microvessels in the brain were visualized using fluorescent microscopy. Areas of perfusion deficits in the brain were traced, calculated and expressed in mm2.

The results showed that US improved neurological deficits significantly (p<0.05). The administration of US significantly decreased perfusion deficits and BBB permeability. In the control set, for the US+high tPA, high tPA only and US only groups, the mean perfusion deficits (±SD) were 14.32±3.15, 7.03±4.08, 5.92±1.90 and 9.14±3.37 mm2, respectively, 8 h after MCA occlusion (P<0.05).

These studies suggest that US is protective in a rat embolic model of stroke due to decreased perfusion deficits.

Exposure to low levels of lead increases blood pressure in humans and animals. Although there are controversial reports about the exact mechanisms of lead-induced hypertension, many factors such as alteration in the cardiovascular responsiveness to endogenous substances including catecholamines could be one of the mechanisms involved. In the present study, the effect of lead acetate on the systolic blood pressure and responsiveness to β-adrenergics was investigated in rats. Through their drinking water, three groups of rats were exposed to 100 ppm lead acetate for periods of 4, 8 or 12 weeks. The blood pressures of the rats were monitored throughout the study. The rat hearts were isolated and perfused with Krebs-Henseleit solution (pH=7.4) at 37˚C and gassed with 95% O2 + 5% CO2. The heart rate (chronotropic) and contractile (inotropic) responses were recorded before and after adding isoproterenol at multiple concentrations to the perfusion solution. The mean blood pressures in the 8 and 12-week lead-treated groups were significantly higher than that of the control group (P<0.01). The chronotropic response to many doses of isoproterenol was significantly increased in the 12-week lead-treated group compared to that of the control group (P<0.05). The inotropic response to this drug was significantly increased in both the 8- and 12-week lead-treated rats (P<0.05 and P<0.01, respectively). Our results indicate that low-levels of lead increase systolic blood pressure as well as both chronotropic and inotropic effects of β-adrenergics, which could imply an important role in the pathogenesis of lead-induced hypertension.

Acute abdominal pain is a common complaint in an emergency setting. An immediate and precise diagnosis is necessary for reducing morbidity and mortality. Several studies have reported that CT scan increases diagnostic accuracy for patients with acute abdominal pain. This study was designed to evaluate the sensitivity, specificity and accuracy of spiral CT scan compared to that of abdominal ultrasound and plain radiography.

We assessed the data of 91 consecutive patients, including 45 males and 46 females, ranging in age from 8 to 84 years (mean age 52.38 years) presenting to the emergency department of Sina Hospital, Tehran, Iran, with acute non-traumatic abdominal pain during the years 2003-2005. All patients underwent spiral CT scanning; in addition, sonography and plain radiography were performed for 66 and 64 of the patients, respectively. The sensitivity, specificity and accuracy were calculated and compared, based on the final diagnosis, which was established with surgical, pathologic, and clinical follow-up. The data was analyzed by SPSS 13.0 software.

Among the 91 patients examined, CT scan was reported to be normal in 15 patients (16.5%). The most common CT findings were aortic aneurysm (12.1%), pancreatitis (9.9%), ovarian cyst (7.7%), intestinal distension (7.7%), and hepatic cyst (7.7%). The overall sensitivity, specificity, and accuracy of unenhanced spiral CT were 92.2%, 92.86%, and 92.3%, respectively, whereas those of plain radiography were 13.2%, 72.7%, and 23.4%, respectively, and ultrasound 73.2%, 90%, and 75.7%, respectively.

This study suggests that plain radiography is an insensitive technique in the evaluation of nontraumatic acute abdominal pain presenting in the emergency department. Unenhanced spiral CT is accurate for adult patients with nontraumatic acute abdominal pain and should be considered as an alternative to radiography as the initial imaging modality.

The most common methods for screening of patients with probable ischemic heart disease are stress test and in special conditions are perfusion scan, so that their positive results was important indication of coronary angiography. Although, predictive value of perfusion scan has been considered, with regard to the impact of technical and specialized factors and according to the spread of this technique that has wrongly replaced the stress test, it is necessary to compare predictive value of this method with stress test in our country. In a cross-sectional study, patients referred to Tehran Heart Center from all centers of country between January 2004 and January 2005 for coronary angiography was included. Demographic characteristics of patients were collected by interview and clinical tests and analyzed in two genders. Then, positive predictive value (PPV) of both techniques was calculated and compared. The total number of positive perfusion scan and stress test were 2178 and 2581, respectively. It was not significant difference between PPV of perfusion scan and stress test in men (86.9% vs 86.6%, P=0.814). PPV of perfusion scan was higher than stress test only in women more than 60 years old (P=0.0002). According to the results of this study and with regard to high cost of perfusion scan, it seems that in case the possibility of stress test, the use of perfusion scan had no advantages with the condition of our scan centers and especially in women, predictive value of these techniques were similar. However, it is necessary to consider the causes of this unusual finding according to the role of drugs, instruments, and specialists in the future.

Nephrotic syndrome is one of the most remarkable diseases in childhood. The majority of patients have prompt response to corticosteroids.

In this study, we retrospectively evaluate the outcome of patients with steroid-responsive nephritic syndrome. Medical records from January 1996 to September 2006 were reviewed to identify all children with steroid sensitive nephrotic syndrome at the Pediatric Medical Center, Tehran, Iran. Initial steroid therapy was 60 mg/m2 per day for four weeks. Levamisole, a steroid-sparing agent, was prescribed at a dose of 2.5 mg/kg on alternate days in conjunction with alternate-day prednisolone. If no benefit was observed by three months, levamisole was discontinued and immunosuppressive therapy with cyclophosphamide at a dose of 3 mg/kg daily for 8 weeks, or cyclosporin A at a dose of 3-5 mg/kg was prescribed.

Of 745 children with steroid sensitive nephrotic syndrome, 63.1% of patients were male. The most common causes were minimal change disease (98/324, 30.2%) and focal segmental glomerulosclerosis (81/324, 25%). At presentation, microscopic hematuria was found in 22.6% of the patients. During follow-up, 9.2% had no relapse at any time, while 15.8% were frequent relapsers. The remission period ranged from 3.5 to 168 months. At the last follow-up, 57.6% of the patients were in remission, 37.7% relapsed and 29 children developed chronic renal failure. The outcome of nephrotic syndrome was not associated with age or gender. The end clinical status of patients correlated with duration of remission, number of subsequent relapses and response to cytotoxic agents.

Steroid-responsive nephrotic syndrome in children should be followed over a long period, especially patients with early relapse. Relapse was seen in more than 90% of patients. Documentation of histopathology by renal biopsy may be helpful to identify those at increased risk for a poor outcome.

There is dearth of reports from Iran regarding the prevalence of postterm pregnancy and its complications. The present study was conducted to evaluate the prevalence, management and outcome of prolonged pregnancies. This cross-sectional study included data from the hospital records of all women referred to Shariati Hospital, Tehran, from 2001 to 2002 with pregnancies of more than 40 weeks in duration. Pregnancies ≥40-42 weeks were considered postdate and those more than 42 weeks postterm pregnancy. The data compiled from the hospital records were subjected to t, χ2 and Mann-Whitney U tests. Of the 1500 deliveries in this hospital, 98 patients were included in this study, 66.3% of whom were nullipara and 33.7% multipara. The prevalence of postterm pregnancy was estimated to be 3.3%. Cervix dilation of 2 cm or less on admission occurred in 65 women (73.3%). The mean Bishop score was 4.31. Of the 62 fetuses that underwent assessment tests, 54 (87.1%) were normal. The median time between the last test and induction of labor was 2.1 days, and 2.6 days for cesarean deliveries, which was not a significant difference (P=0.6). Cervical ripening with misoprostrol was performed in 36 cases (36.7%) and was successful in 18 cases. In this group, the median time for cervical ripening in multiparas was significantly less than nulliparas (4 vs. 7 hrs, P=0.004). Women not subjected to cervical ripening had a higher cesarean rate than those who did undergo cervical ripening (74.7% vs. 66.1%), although this difference was not significant (P=0.9). Vaginal and cesarean delivery rates showed no significant difference between cases that underwent induction with oxytocin and those subjected to cervical ripening with misoprostol (P=0.9). The mean Apgar score was 9.5, with all scores above 6. There were no cases of neonatal hypoglycemia, hypocalcemia, NICU admission or prenatal death. The mean nursery stay was 1.84 days with a range of 1-8 days. The prevalence of postterm pregnancies was 3.3% in this study, due in part to erroneous estimation of gestational age. Sonography exam in the first half of pregnancy can provide a better estimation of gestational age and thereby reduce the rate of postterm pregnancy. Cervical ripening and induction of labor shorten the duration of pregnancy; however, whether it has any beneficial effect on neonatal outcome remains controversial.

Nasogastric tube (NG tube) usage was first described in 1921 by Levin. Surgeons routinely use NG tube in most esophageal resections. Considering the numerous complications caused by this tube, the uncertainty about its usefulness and the scarcity of studies conducted on the subject, particularly in esophageal cancer patients, we investigated the necessity of the NG tube in these cases. This clinical trial was performed at the Cancer Institute of Imam Khomeini Hospital. Esophageal cancer patients were randomized into groups either with or without postoperative NG tube; the latter group was also prescribed metoclopramide. Postoperative obstruction was the exclusion criteria. The operation was done by a team of surgeons using the surgical techniques of McKeown or Orringer. All patients received ranitidine, heparin and antibiotics postoperatively. All patients received postoperative chest X-ray and chest physiotherapy. The NG tube was inserted or reinserted for those with abdominal distention and/or repeated vomiting. The NG tube was pulled out after return of bowel movements. The variables recorded for each patient included the first day of flatus, the first day of defecation, the first day of bowel sound (BS) upon auscultation, duration of post-operative hospitalization, nausea and vomiting, abdominal distension, pulmonary complications, wound complications, anastomotic leakage and the need for placing/replacing the NG tube. Statistical analysis was performed using SPSS, v. 11.5. After randomization, the NG tube was inserted for 22 patients, and 18 patients had no NG tube. The incidence of anastomotic leakage was significantly higher in the NG-tube group. No significant differences between the two groups were found for other complications. The mean times until first passage of flatus, defecation and BS upon auscultation and the duration of post-operative hospitalization were not significantly different. The need for placing/replacing the NG tube was the same for both groups. There was no difference in the perioperative death rates between the two groups. We conclude that the routine use of NG tubes after surgery is not recommended for all patients. NG tube should be used according to the specific needs of each patient. This protocol will protect patients from undesired complications.

Acute lymphoblastic leukemia (ALL) is the most common cancer in the pediatric population. With modern treatments, the chance of the complete recovery is nearly 100%. The most important prognostic factors are appropriate treatment protocol and determination of patient risk factors based on clinical, morphological, immunological and cytological characteristics. In this study we reviewed frequency of these factors, like as age, gender, the primary white blood cell number, sub- group on the base of FAB classification, immunophenotype and the clinical progress. In this retrospective study, we reviewed 877 pediatric patients with the diagnosis of ALL between the years of 1994 and 2004. In these patients the age, gender, primary WBC count, sub-group based on the FAB classification, immunophenotype and the clinical progress in 177 patient with acute lymphoblastic leukemia at Imam Khomeini Hospital between the years of 1994 to 2004 were determined. Of these patients, 1.6% was younger than one year, 24.8% more than ten years old and 73.6% were between the ages of one and ten years; 63.8% were male. WBC counts were above 50,000/ul in 28.8% of the patients. FAB classifications included L1 in 80.2%, L2 in 17.5% and L3 in 2.3% of the patients. Immunophenotypes included pre-B cell in 63.8%, early pre-B cell in 23.1%, T cell in 12.3% and mature B cell in 0.8% of the patients. Marker CD10+ was detected in 88.1% of the B cell cases. In this study group, 74% of the patients recovered, 16.3% died and 16.5% relapsed. The prevalence of FAB-L1 and pre-B cell cases in this study is greater than a previous study, while the prevalence of FAB-L2 and early pre-B cell cases is less than that of the previous study.

The value of the mandibulo-canine index (MCI) in gender identification has been proved in some studies in various countries. The goal of our study was to determine the utility of MCI in gender identification in Iran. This descriptional survey was performed on a group of 18- to 25-year-old Iranian students at the Tehran University of Medical Science. We included 50 males and 50 females that were selected using a single sampling method. Data were statistically analyzed by SPSS (v. 13) and t-test. No statistically significant difference was found between the mean ages of the two groups. Among men, the MCI ranged from 0.209 to 0.293, with a mean of 0.252. Among women, the MCI ranged from 0.202 to 0.276, with a mean of 0.245. There was significant statistical difference between the two means, (0.007; P value = 0.04). The standard MCI of 0.247 was compared to that of each gender, after which no significant statistical difference was found between the two genders (P value = 0.8). Despite some studies performed in other countries displaying the usefulness of MCI in sex determination, our data did not support this conclusion. Perhaps this difference can be explained because of the variety ethnic groups from various cities of Iran represented in this research had some influence on the results.

Proper nutrition has an important role in the physical and psychological development of children. The aim of this survey is to compare the nutrition of a community to the recommended daily amount (RDA) to determine deficiencies and present recommendations for improvement. In this cross-sectional study conducted in Tehran, Iran, 788 children, all seven years of age, were selected via cluster sampling and evaluated using standard questionnaires with a 24-hr recall regarding the frequency and type of food intake. Then by measurement of weight and height, their anthropometric and DMFT (decayed/missing/filled teeth) indices were determined using the Kruskal-Wallis one-way analysis of variance, and Mann-Whitney U and chi-square tests. Relative to the RDA, 23.6% of children had low intake of Ca, and 3.2% and 5.2% were deficient for Fe and Zn, respectively. Anthropometric measurements showed that 15.7% were malnourished based on weight for age, 10.5% based on height for age and 16.8% based on weight for height indices. The DMFT indices for children with dietary Ca levels under 75% of the RDA were significantly higher than those with sufficient Ca intake (P<0.001). The mean DMFT indices for dental development were 0.22 for permanent teeth (four molars; SD=0.64) and 4.64 for primary teeth (SD=3.24). We found a significant correlation between DMFT indices and low Fe intake: the DMFT indices of children with iron deficiency were much higher than those with sufficient iron intake. Children in Tehran do not receive enough Ca Fe and Zn from their diets. This problem causes mild malnutrition and increases the risk of dental caries.

Joint trauma and injury are the most common causes of dynamic instability. Dynamic instability has a great effect on the lumbar spine, due to its three-dimensional motions. The greatest amounts of compression and shearing force are imposed at the points of maximum torque and velocity. The changes in these phase angles upon bearing various loads can cause some pathologic conditions. In this study, we examined the phase angle at maximum torque and velocity in the three planes of movement and then estimated their displacement upon external loads. Using the B200 isoinertial dynamometer, 13 subjects were tested in three stages as follows: 1) Familiarization with tests and apparatus. 2) Warm-up and three maximum isometric tests, with a rest interval between each test, in the three axes of lumbar motion including: flexion/extension, rotation to right/left, lateral flexion to the right/left. 3) Five dynamic tests in these three axes of motion without load, with 25% maximum voluntary torque, and with 50% maximum voluntary torque. Special software was used to analyze the raw data and detect the occurrence of maximum torque and velocity in the dynamic range of motion at each of the three axes. When the load was increased, the maximum dynamic torque in each of the three axes increased (P<0.05). The increase in load shifted the phase angles toward the maximum torque and velocity (P<0.05), with a positive correlation between changes in torque and velocity phase angles (P<0.05). Rather than being a function of the biomechanical pattern, the changes in maximum torque and velocity of the phase angles following an increase in motion resistance to the outer range of the three axes are actually a control behavior in the motion processing system in dynamic movement.

Spider bites are common in most parts of the world. In some areas, where snake or scorpion bites are common, spider bites may not be considered a significant problem by the general public and those who have been bitten by spiders may not go to a hospital. However, significant problems are observed in the victims of certain species of spiders including: widow spider (of the genus Latrodectus), including the black widow and brown spiders (of the genus Loxosceles), such as the brown recluse. Case: We report a six-year-old boy, admitted to the hospital two weeks after suffering a spider bite. The patient presented with a severe nose bleed, ecchymosis and purpura, as well as anemia, indicating a clotting disorder. Laboratory results revealed abnormal values for prothrombin time (PT) >50 sec, partial thromboplastin time (PTT) >120 min and fibrinogen = 0 mg/dl, whereas factor VIII was normal according to a mixing study, with a normal platelet count of 350,000/µl. The patient was managed with fresh frozen plasma every 12 h, and was discharged one week after hospital admission. At present, the patient is well with more normal laboratory results one month after treatment: PT=13.4 sec, PTT= 34 sec, fibrinogen=105 mg/dl. Although spider bites are uncommon in Iran, severe systemic reactions may occur in the pediatric population requiring admission to the pediatric intensive care unit. These systemic reactions may include hemolytic anemia coagulopathy and renal failure.