Detection of the GJB2 Mutation in Iranian Children with Hearing Loss Treated with Cochlear Implantation.

The 35delG mutation in the gap junction protein, ß2, 26kDa (GJB2) gene is the most common mutation that has been found in children with non syndromic hearing loss. Testing for the GJB2 gene mutation is simple and can directly answer the concerns of the parents about cause of the disorder and prognosis for their children. Cochlear implantation (CI) is one of the methods of hearing rehabilitation in patients with complete hearing loss. The present study was designed for genetic assessment of children who were referred for CI. Connexin 26 (Cx26) gene analyses were performed on 42 children with non syndromic hearing loss who were referred to the Baqiyatallah Hospital, Tehran, Iran for genetic consultation and CI. Clinical history was obtained and an examination conducted on each individual. Genomic DNA was extracted from peripheral blood and mutation identification of the Cx26 gene was performed by polymerase chain reaction (PCR) amplification and direct sequencing of the coding sequence of the gene. Cochlear implantation was performed for all patients and treatment response was assessed for all of them based on speech intelligibility rating (SIR) before and after CI. We found six patients (14.3%) with the 35delG mutation on the Cx26 gene, two homozygotes and four heterozygotes. No other mutation was detected. Treatment response in children with the homozygous 35delG mutation was better than in heterozygous patients, and treatment response in children with the mutation was better than in children with no mutation. Mutation screening for finding deafness causing mutations in the GJB2 gene is a useful predictor of post-implantation speech perception. We suggest microarray or other advanced mutation detection methods for assessment of other genes that might be responsible for non syndromic deafness.

Isolation of clinical strains of Pseudomonas aeruginosa harboring different plasmids.

Aim of this study was to investigate the presence of plasmids among the strains of P. aeruginosa isolated from clinically diagnosed cases in Tehran in 2006. A total of 38 strains of P. aeruginosa were isolated. With the exception of one isolate, all P. aeruginosa strains harbored at least one plasmid band. The electrophoretic analysis of plasmid DNAs showed different number of plasmid bands among the strains tested. The DNA band of 1.4 kbp was evident in 84.2% of the strains. Approximately 71 and 21% of the isolates harbored concomitantly two and three plasmids, respectively. Isolation of strains with diverse types of plasmids suggests the different cluster of P. aeruginosa might be disseminated during the current study period.

An outbreak of gastroenteritis of unknown origin in Tehran, July 2003.

Aim of this study was to determine the causative agent and source of a large gastroenteritis outbreak occurred in a national financial center (CBIRI) in July 2003. A patient definition was defined staff were interviewed in the clinic of the Bank and their information were collected by means of a standardized questionnaire. A total of 110 fecal specimens were collected within 48 h of symptom onset from 100 patients with symptoms of gastroenteritis and 10 restaurant staff. The specimens were processed within 12 h to detect ova and parasites by direct microscopy and common bacteria by standard methods. The outbreak started on 22 July 2003 lasted 4 days. From a total of 1300 staff. 535 persons experienced a severe gastrointestinal illness. None but one of tested fecal samples were positive for bacterial enteric pathogens. S. paratyphi B was isolated from the positive case. Definitive association between illness and isolated S. paratyphi B remained to be determined since it was isolated only from one case. There is a need, however, for increased awareness among both professionals and the public to implement appropriate prevention measures and monitoring of food and water.

Phenotypes and mitochondrial DNA substitutions in families with A3243G mutation.

OBJECTIVE: To clarify the relationship between mitochondrial DNA (mtDNA) sequence variations and phenotypes in patients with A3243G mutation. MATERIALS AND METHODS: We studied whole mtDNA sequences in two families with A3243G mutation and characteristic clinical features. Two brothers in Family 1 had shown thiamine deficiency and mitochondrial myopathy without central nervous system involvement. In Family 2, a 16-year-old woman showed the symptoms of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Her mother had had diabetes mellitus and died at the age of 42. The proportion of A3243G mtDNA in blood was 87 and 89% in the patients of Family 1, and 25% in the patient and less than 5% in the mother of Family 2. RESULTS: The mtDNA analysis revealed the following homoplasmic substitutions: T1520C and C12153T found only in Family 1, and A15954G found only in Family 2. These substitutions were not detected in seven other MELAS patients or in 50 controls. CONCLUSION: These substitutions might be specific to these families and could be one of the factors that modulate their clinical features together with the A3243G mutation.