Effect of Hemodialysis on Corrected QT Interval and QTc Dispersion

Hemodialysis patients are at higher risk of cardiovascular disease due to traditional and dialysis-related risk factors. Our aim was to study the effects of hemodialysis on the corrected QT interval (QTc) and QTc dispersion in chronic kidney disease (CKD) without clinically manifest heart disease. Two hundred cases of CKD on chronic intermittent hemodialysis of >3 months' duration were included in the study. Twelve-lead electrocardiography and samples for serum creatinine, potassium, calcium, and magnesium were taken before and after dialysis. The mean age of patients was 52.4 ± 17 years with male-to-female ratio of 3:1. QTc interval and QTc dispersion were prolonged in 47% and 59% before and 50% and 89% of patients after hemodialysis, respectively. The mean values of QTc were 433.4 ± 36.9 ms before and 451.4 ± 39.6 ms after hemodialysis (p = 0.001) and the mean values of QTc dispersion were 60.5 ± 19.3 ms before and 81.5 ± 24.4 ms after hemodialysis (p = 0.001). Similar pattern was observed in all etiological groups of CKD, except for QTc dispersion in malignancy-related CKD (p = 0.216). After hemodialysis, there was a significant fall in the mean values of serum potassium (p = 0.001), rise in serum calcium (p = 0.001), and no change in magnesium (p = 0.424). Patients with post hemodialysis QTc dispersion >74 ms had significantly low mean values of serum potassium and calcium as compared to <74 ms group. Large numbers of hemodialysis patients have a prolonged QTc interval and QTc dispersion with a significant increase in the mean values after hemodialysis. There is a significant fall in serum potassium and rise in serum calcium after dialysis.

One-Parameter Scaling Theory for DNA Extension in a Nanochannel

Experiments measuring DNA extension in nanochannels are at odds with even the most basic predictions of current scaling arguments for the conformations of confined semiflexible polymers such as DNA. We show that a theory based on a weakly self-avoiding, one-dimensional "telegraph" process collapses experimental data and simulation results onto a single master curve throughout the experimentally relevant region of parameter space and explains the mechanisms at play.

Does the presence of Klebsiella pneumoniae carbapenemase and New Delhi metallo-β-lactamase-1 genes in pathogens lead to fatal outcome?

INTRODUCTION

Infections due to multidrug-resistant (MDR) pathogens are a medical challenge. There is considerable apprehension among clinicians regarding pathogens reported as carrying New Delhi metallo-β-lactamase-1 (NDM) and Klebsiella pneumoniae carbapenemase (KPC) genes from their patients. In the face of extremely high rates of antimicrobial resistance, it is essential to gauge the clinical significance of isolation of pathogens carrying these genes from clinical samples. This study compares the outcome of patients infected with pathogens carrying NDM/KPC genes versus those without these genes.

METHODS

The study was conducted over a 1-year period at a Level-1 trauma centre. Hospital-acquired infections were diagnosed on the basis of CDC's criteria. The correlation of isolation of a multi-resistant pathogen carrying KPC or NDM genes with the clinical outcome was ascertained.

RESULTS

A total of 276 consecutive patients admitted to the Intensive Care Units/wards of the JPNA Trauma Centre were included in this study. Of the 371 isolates recovered from these patients, 116 were from patients who had a fatal outcome. The difference in prevalence of blaNDMand blaKPCwas not significant in any genera of Gram-negative pathogens isolated from patients who survived versus those who had a fatal outcome.

CONCLUSION

Isolation of MDR pathogens carrying NDM/KPC genes from clinical samples is not always a harbinger of a fatal outcome. Efforts should be made to prevent cross-transmission of these pathogens.