Study of carD gene sequence in clinical isolates of Mycobacterium tuberculosis.

Mycobacterium tuberculosis growth rate is closely coupled to rRNA transcription which is regulated through carD gene. The aim of this study was to determine the sequence of carD gene in drug susceptible and resistant clinical isolates of M. tuberculosis and designing of a PCR assay based on carD sequence for rapid detection of this bacterium.Specific primers for amplification of carD gene were carefully designed, so that whole sequence of gene could be amplified; therefore primers were positioned at the upstream (promoter of this gene and ispD gene) and downstream (in ispD gene). DNA from 41 clinical isolates of M. tuberculosis with different pattern of drug resistance was used in the study. PCR conditions and annealing temperature were designed by means of online programs. PCR products were sequenced by ABI system.PCR product of carD gene was a 524 bp fragment. This method could detect all resistant and susceptible strains of M. tuberculosis. The size of amplified fragment was similar in all investigated samples. Sequence analysis showed that there was similar sequence in all of our isolates therefore probably this gene is considered to be conservative. Translation of nucleotide mode to amino acids was showed that TRCF domain in N-terminal of protein CarD was found to be fully conservative.This is the first study on the sequence of carD gene in clinical isolates of M. tuberculosis. This conservative gene is recommended for use as a target for designing of suitable inhibitors as anti-tuberculosis drug because its importance for life of MTB. In the other hand, a PCR detection method based on detection of carD gene was recommended for rapid detection in routine test.

Prevalence of QTc interval changes in acute psychiatric care: a cross-sectional study.

INTRODUCTION: In a case series we examined the prevalence and incidence of QT changes during a 1-week interval in hospitalized patients in a general psychiatry ward during a 6-month period. METHOD: This cross-sectional study was done on electrocardiographic QT interval of patients admitted to the Psychiatric Department of Taleghani Hospital during a 6-month period excluding subjects with underlying cause of QT prolongation. RESULTS: Admission and follow-up electrocardiograms of 27 men and 47 women were studied, there was significant QT prolongation during hospitalization (P value 0.001) in approximately 30% of subjects, irrespective of type of administered medication. CONCLUSION: Pro-arrhythmic changes as reflected in QTc prolongation and QTc dispersion in electrocardiograms are common in patients admitted in psychiatric wards irrespective of type of therapy and should be screened and followed by serial electrocardiograms to minimize untoward cardiac outcomes.

Sudden cardiac death after treatment with low dose risperidone in combination with cotrimoxazole.

UNLABELLED: Risperidone as an antipsychotic drug raises the risk of serious ventricular tachyarrhythmias and sudden cardiac death; co-administered with other potentially arrhythmogenic drugs the risk escalates. There are some electrocardiographic markers which may help predict such events. CASE REPORT: We describe a 47-year-old woman with acute psychosis, who died suddenly subsequent to refractory ventricular arrhythmia, while on low dose risperidone combined with cotrimoxazole. CONCLUSION: This case report suggests that use of risperidone even at a low dose and in an apparently healthy individual is associated with a heightened risk of lethal ventricular tachyarrhythmia. Therefore, clinicians should always be aware of such awkward effect. It is recommended to obtain baseline electrocardiogram in all patients and follow up electrocardiograms in selected patients when considering such therapy in order to avoid fatal outcomes.