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Objective: Shiga toxin-producing E. coli (STEC) is a pathogenic E. coli that may cause hemolytic uremic syndrome (HUS) after diarrheal disease through Shiga toxins. Management of the patients with STEC infection is different from that of other diarrheal diseases due to increase in frequency of HUS after antibiotic administration. Few studies were conducted in Iran and epidemiology of STEC remains obscure; this necessitates examination of stools especially in young children for this bacterium., Methods: We determined the frequency of STEC in 947 E. coli strains isolated from diarrheal stools of children less than 14 years in Tehran with conventional culture methods and multiplex-PCR via determining the STX1 and STX2 genes, between October 2008 and September 2009. We also evaluated the association between stool exam findings and presence of STEC., Findings: Twenty seven (2.8%) of E. coli isolates were positive for STX1 or STX2 genes, most of which occurred in spring (P<0.05). There was no significant association between STEC positivity and stool exam findings. Eighteen out of 27 (66.7%) Shiga toxin positive samples were isolated from males and the rest from females. The most common STX-positive diarrheal samples showed loose consistency (P<0.017)., Conclusion: Although the low frequency of STEC in our population indicates that it is not a major problem in our population, STEC should be regarded as an important infection because of its severe consequences. Further studies with greater sample size are needed to confirm our results.

Objective: Alpha1-antitrypsin deficiency (A1ATD) is the most important indication for liver transplantation in children. The gene frequencies vary in different ethnic groups. In the present study, we attempt to determine the frequencies of the most common defective alleles, Z and S, in Iranian children suffering from idiopathic neonatal cholestasis. Eighty-seven infants were typed for Z and S alleles., Methods: In a single center study, 87 consecutive liver biopsies from infants with cholestasis were reviewed and patients with neonatal cholestasis enrolled in the study and cases with confirmed biliary tract atresia excluded. Formalin fixed paraffin embedded blocks were used for DNA extraction. AAT genotype was determined by polymerase chain reaction (PCR) assay and amplification of the two most common deficiency variants, S and Z alleles, and then sequencing of PCR products., Findings: There were 48 (55.2%) males and 39 (44.8%) females, with a median age of 60 days. Out of 87 of the study subject, 2 (2.2%) were heterozygous for the S allele, and no ZZ, SS or MZ individual was found in the patients. No other polymorphism was found in the sequencing results., Conclusion: In comparison to other populations, AAT deficiency seems not to be an important etiologic factor for neonatal cholestatic liver disease in Iran; however, further studies are recommended to estimate the true mutant gene frequencies.

Objective: Exposure to environmental tobacco smoke (ETS) is one of the major factors of predisposing children to develop several hazardous health problems. We decided to investigate the association between nicotinine, one of the nicotine metabolites and esophagitis in children with gastroesophageal reflux disease (GERD)., Methods: In a case control study 46 children suffering from esophagitis referred to endoscopy ward were recruited. The control group consisted of 45 healthy children. Urine samples were collected and urinary cotinine level (UCL) measured., Findings: The mean age of esophagitis and control groups were 5.11±2.93 and 6.72±2.8 respectively. Sixty children were passive smokers; 31 of them had non-smoker parents. In control group, 32 (71.1%) children and in esophagitis group 29 (63%) children had non-smoker parents. The mean value of UCL in patients suffering from esophagitis was significantly higher than those in normal group (P=0.04, 24.98±6.4 ng/ml vs. 15.16 ± 3.9 ng/ml). Considering 50ng/ml as a cutoff point for UCL, it was significantly higher in passive smoker group than in non smoker group (P=0.02). The mean cotinine level differed significantly in esophagitis and control group., Conclusion: Our results indicate the increased risk of developing esophagitis in children with ETS exposure.

Objective: Wilson's disease (WD) is an autosomal recessive disease with genetic abnormality on chromosome 13 causing defect in copper metabolism and increased copper concentration in liver, central nervous system and other organs, which causes different clinical manifestations. The aim of this study was to determine the sensitivity of different clinical and paraclinical tests for diagnosis of Wilson's disease., Methods: Paraffin blocks of liver biopsy from 41 children suspicious of WD were collected. Hepatic copper concentrations were examined with atomic absorption spectrophotometry (Australian GBC, model: PAL 3000). Fifteen specimens had hepatic copper concentration (dry weight) more than 250μg/g. Clinical and laboratory data and histologic slides of liver biopsies of these 15 children were reviewed retrospectively. Liver tissue was examined for staging and grading of hepatic involvement and also stained with rubeonic acid method for copper., Findings: Patients were 5-15 years old (mean age=9.3 years, standard deviation=2.6) with slight male predominance (9/15=60%). Five (33%) patients were 10 years old. Three (20%) of them were referred for icterus, 8 (54%) because of positive family history, 2 (13%) due to abdominal pain and 2 (13%) because of hepatosplenomegaly and ascites. Serum AST and ALT levels were elevated at the time of presentation in all patients. In liver biopsy, histological grade and stage was 0-8 and 0-6 respectively, 2 (13%) had cirrhosis, 1 (7%) had normal biopsy and 12 (80%) showed chronic hepatitis. Hepatic copper concentrations were between 250 and 1595 μg/g dry weight. The sensitivity of various tests were 85% for serum copper, 83% for serum ceruloplasmin, 53% for urinary copper excretion, 44% for presence of KF ring and 40% for rubeonic acid staining on liver biopsies., Conclusion: None of the tests stated in the article were highly sensitive for diagnosis of WD, so we suggest that diagnosis should be based on combination of family history, physical examination and different tests.

Objective: Acute appendicitis is the most common cause of abdominal surgery in children. Similarity between signs and symptoms of appendicitis and other common pediatric illnesses, atypical manifestations of appendicitis in young children, and children's inability to give precise explanation for their symptoms contribute to considerable delay in proper diagnosis and increased rate of perforation. Current study reports the surgical and pathological findings of appendectomies in the largest Children's Hospital in Iran. It also evaluates whether common protocol for pathologic evaluation following appendectomy is beneficial., Methods: Pathologic reports of 947 appendectomies, performed with the presumptive diagnosis of acute appendicitis, were gathered. Correlation between surgical and pathologic findings was assessed. Demographic characteristics of patients between surgical and pathological subgroups were also compared., Findings: The mean age of participants was 6.9±3.5 years. Eighty seven (25.5%) children had abnormal pathological findings and normal surgical report. None of miscellaneous findings including appendicular carcinoid tumor 3 (0.3%), oxyuriasis 2 (0.2%), and mycobacterial infection 4 (0.5%) were recognizable during the surgery. Of all pathologically confirmed cases with perforated appendicitis, 9.7% were not detected during the surgery., Conclusion: In current study, acute appendicitis was the most common pathological diagnosis, however, high normal appendectomy rate along with noticeable proportion of surgically missed perforated appendicitis and unusual histopathologies strongly supported routine histological examination.

Objective: Hirschsprung's disease (HD) is a complex disorder resulting from absence of ganglion cells in the bowel wall leading to functional obstruction and bowel dilatation proximal to the affected segment. The aim of our study was to evaluate rectal biopsies from constipated children in different age groups to see in which age it is more likely to encounter HD to avoid unnecessary rectal biopsy., Methods: Records of all children with chronic constipation undergoing a rectal biopsy to exclude HD were obtained from the files of Children's Medical Center in Tehran, Iran. A detailed retrospective demographic review, including age of beginning of signs and symptoms was made of all cases., Findings: Totally, 172 biopsies were taken from 168 children in a five year period, of which 127 cases (75%) had HD. The mean age of constipated patients at biopsy was 39 months and the mean age of patients with proven HD was 18 months. Males were affected more than females. Congenital anomalies associated with HD were found in 9.6%. In 85 (91%) cases constipation had begun in neonatal period., Conclusion: Our data supports previous studies that if constipation begins after the neonatal period, the child is unlikely to have HD. In neonates delay in meconium passage is the most important clinical sign of HD.

Background: Liver storage diseases are rare biochemical and inherited diseases that affect multiorgan systems., Objectives: This study was performed to determine the rate of storage diseases and their types in liver pathology specimens of subjects who were referred to a tertiary pediatric center., Patients and Methods: Two pathologists evaluated 2216 pathology specimens (stained with hematoxylin and eosin and periodic acid-Schiff) from subjects who were referred to the largest pediatric tertiary referral center in Iran between 1996 and 2007. Baseline data and clinical and laboratory manifestations were retrieved from the patients' files., Results: We identified 117 patients who had storage diseases. A combination of clinical and laboratory findings was used to assess the final diagnosis. Glycogen storage disease (GSD) was observed in 85 of cases, compared with lysosomal storage diseases (LSD) in 31 patients and mucopolysaccharidoses in 1 case. LSD was more prevalent in those aged between 1 month and 1 year, whereas GSD was more frequent in those aged between 1 and 6 years. Most of the patients aged between 1 and 6 years. Most patients with LSD and GSD had unknown types of the disease. The most common known types in the LSD and GSD groups were Niemann-Pick disease and GSD type I respectively. The most common clinical and laboratory manifestation was hepatomegaly and abnormal liver enzymes, respectively., Conclusions: Most of our patients with storage diseases had Gaucher disease. Hepatomegaly and elevated transaminase levels were the most striking finding. However, with regard to the limitations of our methodology, further studies that collect more accurate data are warranted.

Objective: Beta-thalassemia major is an autosomal recessive disease causing severe and hemolytic anemia, which begins about 2-6 months after birth. Iron overload, which arises from recurrent transfusion and ineffective erythropoiesis, can enhance oxidative stress in thalassemic patients. The aim of this study was to evaluate the serum total antioxidant capacity of patients with ß-Thalassemia major., Methods: Sixty six Iranian patients with β-thalassemia major and 66 age-gender matched controls were evaluated for serum total antioxidant status (TAS), uric acid (UA), bilirubin and albumin. In addition, serum ferritin and transaminases were recorded in these subjects., Findings: Significant increases of TAS, UA, and bilirubin were observed in the patient group, compared with the control group (P<0.01). Mean TAS and bilirubin in male patients was higher than in females (P=0.005 and P=0.008, respectively). There was also direct correlation between TAS and albumin (P<0.001), bilirubin (P<0.001) and UA (P=0.002)., Conclusion: Endogenous antioxidants such as ferritin, UA and bilirubin can result in increased level of TAS in the patients with Beta-thalassemia major. Compensatory excess of TAS to oxidative stress could also be the reason for difference between our findings and previous studies.

Objective: This study aims to evaluate the role of breastfeeding in the acquisition of Helicobacter pylori (H. pylori) infection in Iran and to compare the histopathologic changes occurring in children feeding on breast milk with those in infants feeding on formula., Methods: In a case-control study parents of children with and without H. pylori infection who had undergone endoscopic survey and gastric biopsy in the Children's Medical Center, Tehran, were asked about their feeding practices during the first 6 months after birth, the duration of breastfeeding period, the symptoms, and the duration of symptoms and concomitant diseases., Findings: A total of 154 children were included in this study. From this sample, 77 children formed the case group and 77 children formed the control group. A significant difference was found between H. pylori infection and feeding with formula (P=0.045). In case group, a significant difference was found between breastfeeding and age of the infected child (P=0.034), shorter duration of symptoms (P=0.016), and finally degree of H. pylori colonization (P=0.021)., Conclusion: It appears that breastfeeding in the first 6 months after birth can decrease the degree of H. pylori colonization, postpone infection until older age, shorten the duration of symptoms, and be concomitant with milder gastritis.