Tehran University Medical Journal
Year:2007 | Volume:65 | Issue:1|Papers Count:19

Airway management is one of the most important subjects in medicine. This article reviews the history, assessment of airway prior to anesthesia, techniques and equipment of airway management and management of patients with anticipated and unanticipated difficult airways. This article covers recent literature on airway appliances and devices and their use in different circumstances. Airway assessment methods especially the recent Iranian method have been reviewed and discussed briefly in this article. On the whole the article covers the etiology of difficult airway and offers guidelines for safe practice of anesthesia in patients in whom airway is anticipated to be difficult.

Background: Streptokinase (SK) is an effective and specific thrombolytic treatment of acute myocardial infarction. Despite its significant limitations, streptokinase remains the drug of choice particularly in countries with poorer economies because of its relatively low cost. In this study, the production and purification of streptokinase using a pMAL expression vector were evaluated.Methods: The pMAL vector, including the skc gene, obtained from Streptococcus equisimilis H46A, was transformed into E. coli BL21 to produce the soluble active fusion protein SK-MBP. The conditions of SK production were optimized by manipulating temperature, induction time and IPTG concentrations. This protein was purified by DEAE-sepharose column chromatography and the final purity was determined and activity of purified SK-MBP was measured using a synthetic substrate (S2251).Results: After optimizing the production conditions, SK-MBP was the major portion of total protein. Purified SK-MBP formed a single band using SDS-PAGE and had high biological activity.Conclusion: In this study we used pMAL expression vector to produce SK-MBP in E. coli BL21. Using this method we prevented the accumulation of inclusion bodies in spite of the high level of production of SK-MBP. Choosing a suitable host organism for the production of recombinant proteins is one of the most important factors that influence the level of desired protein production. Further studies are recommended to test other host organisms for this purpose.

Background: Helicobacter pylori (H pylori) is one of the major causes of peptic ulcer, gastritis and gastric cancer. This bacterium has a special lipopolysaccharide (LPS), which's responsible for its pathogenesis and its high resistance against gastric acid and escape from the human immune system. This property makes it a target for further research and diagnostic goals. In this study, the extraction of the LPS and separation from the outer membrane is required. Methods: The LPS was extracted from the outer membrane or envelope of H.pylori obtained from patients suffering from gastritis, gastric ulcer and gastric cancer. LPS extraction was performed using the proteinase K method. SDS-PAGE and silver staining were applied to investigate the electrophoretic pattern of the LPS. This pattern was compared with that of E. coli serotype O111 :B4 and Salmonella serotype ATCC 14028. Results: The extracted LPS has a ladder-shaped electrophoretic pattern and the bandsare located in three groups: high, medium and low molecular weights. Conclusion: The distribution of the bands of the ladder-shaped electrophoretic pattern is caused by the different number of oligosaccharide chains associated with the LPS.The high molecular weight bands represent S-LPS and the low molecular weight bands represent the R-LPS, which lacks the O-chain.  

Background: Malaria is still one of the main health problems in south and southeast provinces of Iran and recently on average 10,000-30,000 malaria cases were reported annually. Mosquitoes of Anopheles superpictus are one of the main malaria vectors in Iran and have been reported from all areas of the country including central plateau and plains of Alborz and Zagrous Mountains chains, and with low numbers in shore plains of the Persian Gulf and Caspian Sea. There are variations in larval and adult morphological characters and also in vectorial capacity of this species in different areas of Iran.Methods: This study has been conducted to investigate rate of mtDNA variation among various populations of this species in Iran. The sequence variation of an 1512 bp length of mitochondrial DNA (mtDNA) cytochrome oxidase subunits 1 and 2 (COI-COII) and an 708 bp sequences of COI gene were analyzed by PCR-RFLP and PCR-direct sequencing respectively.Results: This study showed that there are considerable variations between and within populations. Rate of variation was 12.3 % between populations and this was 2-5% for within Baluchistan population. Totally 4 haplotypes were observed between populations where 3 occur in Baluchistan and one in other places.Conclusion: This is the first report on existence of various haplotypes in An. Superpictus in science, and presumably this species comprising siblings and is a species complex. Further studies need to confirm this result and to determine the relationship between mtDNA haplotypes and their role in malaria transmission in each locality.

Background: The incidence of ESBL producing species have been steadily increased in recent years, resulting in limitation of infection control issues and therapeutic options.The purpose of this study was to evaluate prevalence of Enterobacteriaceae and also assess epidemiology ESBL producing strains isolated from patients admitted in ICUs.Methods: A total of one hundred fifty isolates were collected from urine, sputum, blood, wound and other clinical samples from patient admitted in ICU and then were identified by biochemical tests .All of the samples were screened by DAD method according to The NCCLS Guideline. The species that met NCCLS screening criteria was further tested for Clavulanic Acid effect by confirmatory method.Results: A total of one hundred fifty isolates,133 (89.3%) were found to be resistant at least on of the indicators cephalosporin tested according to NCCLS Guideline. 121 (80.6%) of the isolates were resistant to all the indicators tested .89 (59.3) isolateds were confirmed as ESBL producers. The number of isolates ESBL producing was as follow: Klebsiella pneumoniae 33 (76.74%), E.coli 20 (60.60%), Enterobacter cloacae 8 (47.05%), Citrobacter diversus 6 (54.54%), Enterobacter aerogenes 7 (53.84%), Citrobacter freundii 4 (40%), Klebsiella oxytoca 6 (62.5%), Proteus mirabilis 4 (50%), Serratia marcescens 2 (40%), Proteus Volgaris 0%.All of the isolates sensitive to imipenem.Conclusion: The present study shows high prevalence of ESBL producing Enterobacteriaceae from patients admitted in ICU .The increased rate of these species in most cases due to the administration of inadequate and irrational antimicrobial therapy .To overcome this problem, it needs to develop new antimicrobial agents, limiting the Unnecessary Use of antimicrobial and increasing compliance with infection control issues.

Background: Respiratory failure and crisis is one of major complications of thymectomy in myasthenia gravis patients. There are different medication regimes for preparing these patients for surgery and reducing post-operative side effects. The goal of this study is to compare respiratory complications of oral vs. Parenteral preoperative administration of anticholinesterase agents for thymectomy in myasthenia gravis patients.Methods: This randomized controlled trial included 101 patients in class IIA or IIB of myasthenia gravis according to the Osserman classification system. The control group fasted for eight hours before surgery and oral anticholines-terase agents were replaced with parenteral ones. The case group also fasted for 8 hours before surgery, but pyridostigmine was continued at its usual dose until the time of operation and the last dose was given to patients with a small amount of water in the operating room on the operating bed.Results: There was no statistically meaningful difference between the two groups in terms of age, sex and pathologic findings. In comparison, the mean hospital stay for the case group was 3.98 days and 6.34 for the control group (p value = 0.003). There were eight cases of respiratory crisis or failure (16%) in the control group but only 1 case (2%) was observed in case group (p value = 0.014). Only one patient in the case group required re-intubation after the surgery; however, six patients in control group were re-intubated (p value = 0.053). Plasmapheresis was required for five patients in the control group and one patient in the case group (p value = 0.098). Tracheostomy was performed on two patients in the control group to accommodate prolonged intubation, but none of the case group required this procedure.Conclusion: This study shows that continuing oral anticholinesterase agents up to the time of operation, with the last dose at the operative theater, lowers the incidence of postoperative myasthenia crisis and respiratory failure, need for plasmapheresis and shortens the hospital stay. This method may also decrease the need for re-intubation, mechanical ventilation and tracheostomy, thus decreasing the chance of death resulting from complications of the thymectomy.

Background: Simple bone cyst is a common benign lesion in the proximal humerus, especially in prepubertal children. Up to 75 percent of patients with the bone cyst have a pathologic fracture and the most significant complication is recurrent pathologic fracture. Since the process of spontaneous healing of these fractures is rare, treatment is required. Ideal treatment for simple bone cyst should stabilize pathologic fractures, assist healing and provide a quick return to normal activity with reduced complication and recurrence.Methods: In this descriptive case series study, 24 patients with simple bone cysts of the humerus were selected for retrograde flexible intramedullary nailing from the lateral cortex of the distal humerus, since 2000 to 2005 at Imam Khomeini Hospital, Tehran. The mean age of the patients was 14.4 years, ranging from 6-39 years. Results were evaluated by plain radiography using the classification system of Capanna et al.Results: The mean duration of follow up for 23 of the patients was 31 (9-51) months. One patient with short-term of follow-up was excluded. Of these patients, 91.3% were healed either completely (65.2%) or with residual minor defect (26.1%). Only one cyst (4.3%) persisted with no response to treatment and one patient (4.3%) had a recurrence of the cyst. However, there was no instance of recurrent pathologic fracture among these patients.Conclusion: This study shows that flexible intramedullary nailing is an effective treatment for humeral simple bone cysts that reduces the chance of complication, recurrence of cyst or pathologic fracture. This technique provides sufficient stability for quick return to normal activity.

Background: Premature coronary artery disease (CAD) has a familial predisposition and occurrence. We determined the prevalence of CAD and related risk factors in individuals with a history of premature CAD in their first-degree relatives.Methods: This study included 700 healthy individuals with a history of premature CAD in their parents or siblings in Tehran Heart Center in 2003-2004. History of smoking, diabetes mellitus (DM) or hypertension was taken. Fasting levels of blood sugar (FBS), triglycerides (TG), cholesterol, LDL and HDL were measured. Noninvasive studies for CAD were performed with resting echocardiography (ECG) and ECG with exercise tolerance test (ETT). Patients with positive findings for ischemia in these tests underwent a myocardial perfusion scan and if positive proceeded to coronary angiography.Results: The mean age of our subjects was 35.2 (15-65) years. DM was found in 5.3%, smoking in 14.7%, hypertension in 20.6%, cholesterol above 200 mg/dl in 39.9%, TG above 150 mg/dl in 58.6%, LDL above 130 mg/dl in 38% and HDL below 40 mg/dl in 32.6%. In addition, 6.4% had ECG changes and 3% echocardiographic abnormalities in favor of ischemia. ETT was positive in 7.3% and myocardial perfusion scan in 2.1%. Coronary angiography showed 50-70% stenosis in eight patients (1.1%) and >70% in four patients (0.6%).Conclusion: High cholesterol, TG and LDL and low HDL were found among our subjects. Risk factor determination in these individuals may prove to be beneficial. Noninvasive tests for CAD yield low true-positive results and are not recommended in the population as a whole. In certain subgroups, including those with persons older than 40 years and diabetic patients, these tests may be useful.

Background: Tibial and femoral fractures, commonly seen in emergency departments, may be associated with various knee ligament injuries. The aim of this study was to determine the prevalence of such fracture-associated knee ligament problems, with especial attention to rapid diagnosis.Methods: This study was carried out in patients with femoral or tibial fractures who were operated on in Imam Khomeini Medical Center from March 2003 to March 2005. All patients underwent surgical repair immediately after acute fracture, followed by a thorough knee examination. Patients with positive clinical findings were further evaluated using the stress view and arthroscopy.Results: We enrolled 470 cases in this study, of which 266 were tibial and 204 were femoral fractures. There were 404 men and 67 women; with an average age of tibial fracture patients were 34.5 and 44.6 years for those with femoral fractures. Of all fractures, 66% were due to car accidents, 16% to industrial accidents and 8% due to falling. The overall prevalence of ligament injuries in tibial fractures was as follows: 6.58% ACL tearing, 2.5% PCL, 21.95% MCL and 14.63% LCL. The overall prevalence of ligament injuries in femoral fractures was as follows: 6% ACL tearing, 3% PCL, 14% MCL and 8% LCL.Conclusion: The prevalence of ligament injuries of the knee was highest in distal femoral and tibial plateau fractures. It is prudent to perform a thorough knee examination once the fracture is stabilized in the operating room for the early detection of ligament injuries and prevention of further complications.

Background: The incidence of inguinal hernia is 15 cases per 1,000 populations. The most common surgical methods of hernia repair are conventional open hernioplasty and laparoscopic hernioplasty. The advantages of laparoscopic hernioplasty are that the regional anatomy is observable, and bilateral herniorrhaphy can be performed at the same time. Since laparoscopic hernia is usually performed under general anesthesia, to shorten the length of hospital stay and to prevent complications, in this study, we evaluated the use of epidural anesthesia during hernioplasty.Methods: This study included 20 male patients treated by a single surgeon. We recorded the PCO2 levels before, during and after surgery, as well as the pain and intra-abdominal pressure.Results: Only one patient required conversion to general anesthesia. Three patients had hernia on the left side only, 14 patients on the right only and three patients had bilateral hernia. The PCO2 levels did not change (P=0.789). Fifty percent of patients had no postoperative pain. The median time to return to work or normal physical activity was 7 days.Conclusion: Laparoscopic inguinal herniorrhaphy is a feasible alternative to open surgical hernia repair. Employing epidural anesthesia prevents the complications of general anesthesia. This method achieves a shorter hospital stay and time to return to normal activity, as well as reduction in pain. Controlled trials comparing laparoscopic and tension-free open herniorrhaphy are needed to further assess the relative benefits of this procedure.

Background: Atrial and ventricular arrhythmias are among the most common complications after coronary artery bypass graft (CABG) surgery. Previous studies demonstrated that cardiopulmonary bypass itself results in reduced serum magnesium levels. In this study, we evaluated the effect of total blood magnesium level (TMG) on the prevention of perioperative arrhythmias with routine regimens of 2-4 grams supplemental magnesium (SMG).Methods: TMG was measured in patients who were scheduled for CABG on three occasions: just before anesthesia, just after entering the intensive care unit (ICU) after completion of the sugery, and on the first morning after the operation. Patients were evaluated for primary cardiac rhythm and other variables that could have an influence on the magnesium level, including serum creatinine, urine output in the operating room and diuretic therapy. The SMG dosage was also recorded in the operating room and ICU. Patients were then evaluated for the rate and type of arrhythmia for the next three days.Results: The mean TMG levels in 174 cases were 2.2 (0.5), 2.6 (0.6) and 2.4 (0.6) mg/dl for the three occasions, respectively. The mean SMG was 2.5 (1.2) grams. Of 164 patients, 51 (31%) developed the following post-operative arrhythmias: AF (7.3%), non- AF SVA (15.2%) and ventricular (16.5%). The mean serum creatinine level and urine output were 1.2 mg/dl and 1800 ml, respectively. Although there was a significant difference between the TMG levels on the three different occasions (P<0.001), all values were within normal range. When we stratified the TMG levels of the patients based on administered SMG, the Mentel- Haenszel test revealed no significant difference between the first and third TMG (P=0.6). Although the TMG levels were higher in arrhythmic patients compared to those without arrhythmia (2.25 vs. 2.14 mg/dl), both values were within the normal range and there was no significant difference between the two groups. Serum creatinine levels and urine volume were not related to TMG levels.Conclusion: This study indicates that routine magnesium administration has no significant effect on SMG levels. Also, serum creatinine and urine output are not determinant factors for SMG administration. There was no correlation between TMG levels and perioperative arrhythmia. We conclude that the routine regimen of magnesium administration has no effect on the incidence of perioperative arrhythmia, though it is necessary for maintaining normal magnesium levels.

Background: Hyperuricemia is one of the oncologic emergency that occurs most often in patients with hematologic disorders particularly leukemia and high-grade lymphoma. This study was conducted in order to determine the prevalence of hyperuricemia with respect to prophylactic treatment (in particular allopurinol) in patients with ymphoproliferative disease in the pediatric hematologic ward of Imam Khomeini Hospital, Tehran.Methods: In this retrospective cross-sectional study, 316 children (75 females, 241 males) under the age of 12 years participated. Among the subjects, 66 patients (20.9%) had lymphoma and 250 patients (79.1%) had leukemia.Results: Of the 56 (17.7%) patients diagnosed with hyperuricemia, 13 with lymphoma (19.7%) and 43 (17.2%) with acute lymphoblastic leukemia, 52 patients showed hyperuricemia after induction of chemotherapy (p<0.001). Hyperuricemia was more prevalent in patients with more advanced disease (50.9% in stage IV, p<0.001). Hyperuricemia was more frequent in male patients (p<0.001). Among the 217 patients who had received prophylaxis (hydration, alkalization, allopurinol), 19 (8.7%) subjects had hyperuricemia compare to 37.3% in the group of patients who did not receive prophylactic treatment (p<0.001).Conclusion: From the literature reviewed, a recombinant form of the urate oxidase enzyme (rasburicase) is a safe and effective alternative to allopurinol to rapidly control plasma uric acid concentrations in patients with hematologic malignancy at high risk for tumor lysis during induction of chemotherapy. In this respect, we recommend a prospective study to compare allopurinol and rasburicase in children with leukemia and lymphoma.

Background: The cause of osteoporosis is multifactorial and many dietary factors are important in the prevention of this disease. Antioxidants as free radical scavengers may influence osteoporosis by reducing the effects of oxidative stress that may be associated with bone loss. Vitamin E is an important antioxidant that protects polyunsaturated fatty acids (PUFA) in cell membranes from oxidation. There are only two studies regarding vitamin E plasma levels in subjects suffering from osteoporosis. The purpose of this study was to investigate the association between plasma vitamin E levels and bone mineral density (BMD) in Iranian patients.Methods: Subjects were consecutively recruited between May and September 2005 from among a total of approximately 1000 people referred for instrumental screening for osteoporosis to the Jami Clinic in Tehran. Inclusion criteria for the study group were: a femoral neck T-score of -1 or less, osteopenia, severe osteopenia and osteoporosis. A total of 137 subjects were enrolled. According to their femoral and spinal BMD scores, 54 persons were selected as a control group. The control group consisted of subjects with a femoral neck T-score and spine T-score of -1 or more. In selecting the case group, only the femoral BMD score was used. Plasma vitamin E was measured, after extraction with methanol, by HPLC with UV detection at 280 nm. Methanol, deionized water and butanol (90:4:6) was used as a mobile phase with a C8 column. The flow rate was 1.0 ml. min-1 and the acetate ester of vitamin E was used as an internal standard.Results: The results show no significant difference in plasma vitamin E between the control and case groups, however linear regression analysis does reveal a significant difference between the T-score and plasma vitamin E. Conclusion: Deceleration Femoral bone Density during osteoporosis will be accelerated with Decrease of Vitamin E Antioxidant level.

Background: Quality assurance is a prevention-oriented system that can be used to improve the quality of care, increase productivity and monitor the performance management in clinical laboratories. ISO 9001: 2000 requirements are a collection of management and technical systems designed to implement quality assurance and monitor performance management in organizations. Methods: A checklist was prepared to monitor the preanalytical, analytical and postanalytical stages of laboratory performance management in 16 areas and all laboratory activities in 14 of the clinical laboratories of the Tehran University of Medical Sciences (TUMS) hospitals. Collected data were stored and statistically analyzed using SPSS software. Results: The best performance, in which 77.73% of quality assurance indicators were observed, was found in Sina Hospital. However, only 57.56% of these indicators were fulfilled at Farabi Hospital, with the lowest-level performance among the clinical laboratories of TUMS hospitals. The highest level of compliance with quality assurance indicators was in the hematology departments and for facility demands in management areas. Overall, quality assurance indicators were appropriately followed in only 7% of the clinical laboratories. Conclusion: The average quality assurance observation rate in the clinical laboratories studied was 67.22%, which is insufficient and must be remedied with stricter enforcement of the ISO 9001: 2000 regulations.