Comparative Analysis of the Efficacies of the GeneXpert and Solid Culture Media Techniques in the Diagnosis of Mycobacterium Tuberculosis.

Tuberculosis is one of the predominant infectious diseases causing significant deaths worldwide. Detection of Mycobacterium tuberculosis bacilli (MTB) using culture media was officially recognized by World Health Organization. However, there is a significant limitation in the authenticity of evaluation for its effectiveness on clinically important attributes. GeneXpert detects the presence of Mycobacterium tuberculosis (M. tuberculosis) based on the detection of nucleic acid and is able to identify the resistance of both isoniazid (INH) and Rifampicin (RIF) drugs. In this technique, DNA amplification is done using the GeneXpert instrument in the suspected sample with a specific reagent cartridge. Although GeneXpert is a rapid technique compared to other diagnostic tools for MTB identification due to false-negative results, the culture media technique is still considered the gold standard in detecting M. tuberculosis. The current study was designed to evaluate the comparative efficacies of GeneXpert and the solid culture media technique in identifying MTB. Sputum samples of 250 (n=250) suspected tuberculosis (TB) patients were investigated using both diagnostic techniques. The results revealed that out of the 250 suspected patients, 30 (12%) samples were positive with the culture media technique, while only 17 (6.8%) samples showed positive results with GeneXpert. Culture tests and GeneXpert are not equally efficient in detecting M. tuberculosis. The current study's findings showed that the culture-based detection method for M. tuberculosis is more efficient and reliable than GeneXpert.

Social and psychological factors affecting eating habits among university students in a Malaysian medical school: a cross-sectional study.

BACKGROUND: Eating habits have been a major concern among university students as a determinant of health status. The aim of this study was to assess the pattern of eating habits and its associated social and psychological factors among medical students. METHODS: A cross sectional study was conducted among 132 medical students of pre-clinical phase at a Malaysian university. A self-administered questionnaire was used which included questions on socio-demography, anthropometry, eating habits and psychosocial factors. RESULTS: Mean (± SD) age of the respondents was 22.7 (± 2.4) years and (the age) ranged from 18 to 30 years. More than half had regular meals and breakfast (57.6% &, 56.1% respectively). Majority (73.5%) consumed fruits less than three times per week, 51.5% had fried food twice or more a week and 59.8% drank water less than 2 liters daily. Eating habits score was significantly low among younger students (18-22 years), smokers, alcohol drinkers and those who did not exercise. (p<0.05). Four psychological factors out of six, were significantly associated with eating habits (p<0.05). In multivariate analysis, age and 'eating because of feeling happy' were significantly associated with eating habits score (p<0.05). CONCLUSION: Most of the students in this study had healthy eating habits. Social and psychological factors were important determinants of eating habits among medical students.

Fluid structure interaction simulation of left ventricular flow dynamics under left ventricular assist device support.

For patient's receiving mechanical circulatory support, malfunction of the left ventricular assist device (LVADs) as well as mal-positioning of the cannula imposes serious threats to their life. It is therefore important to characterize the flow pattern and pressure distribution within the ventricle in the presence of an LVAD. In this paper, we present a 2D axisymmetric fluid structure interaction model of the passive left ventricle (LV) incorporating an LVAD cannula to simulate the effect of the LVAD cannula placement on the vortex dynamics. Results showed that larger recirculation area was formed at the cannula tip with increasing cannula insertion depth, and this is believed to reduce the risk of thrombus formation. Furthermore, we also simulated suction events (collapse of the LV) by closing the inlet. Vortex patterns were significantly altered under this condition, and the greatest LV wall displacement was observed at the part of the myocardium closest to the cannula tip.

Mutation screening at the RNA level of the STK11/LKB1 gene in Peutz-Jeghers syndrome reveals complex splicing abnormalities and a novel mRNA isoform (STK11 c.597(insertion mark)598insIVS4).

This study was intended to evaluate a diagnostic reverse transcriptase polymerase chain reaction based protein-truncation test for the identification of germline mutations in the serine/threonine protein kinase 11 (STK11, also designated LKB1) gene in Peutz-Jeghers syndrome (PJS). Our data exemplify that the inactivation of STK11 can be due to unusual disturbances in splicing regulation which result in truncations of the protein. However, nonsense mediated mRNA decay must be blocked with puromycin to detect shortened STK11 gene products contained in the leucocytic mRNA pool of PJS patients. Interestingly, two mutations escaped from detection by exon sequencing techniques with usual flanking PCR primers, since alterations were located right in the middle of intronic sequences. We describe a compound heterozygous PJS patient who carried two different mutations in intron 1 on separate alleles. Each of the two mutations was transmitted individually to one of his two children. In the course of our RNA based analyses we detected high level expression of a novel STK11/LKB1 mRNA variant retaining intron 4 (STK11 c.597(insertion mark)598insIVS4) in various tissues. This mRNA isoform was initiated from an alternative transcription regulatory region as revealed by primer extension analyses even in cell lines with complete methylation of the normal promoter. As a consequence of novel mutational mechanisms identified we discuss the impact of RNA based strategies for the detection of germinal STK11 mutations in PJS.