Usefulness of Serum Brain Natriuretic Peptide Level for Screening Hemodynamically Significant Patent Ductus Arteriosus in Preterm Neonates

Objective:

We studied usefulness of serum B-type natriuretic peptide level as a screening tool for detecting hemodynamically significant patent ductus arteriosus in the preterm neonates.

Methods:

Sixty admitted preterm neonates with gestational age ≤34 weeks, birth weight ≤2500 gr, and age of >3 days have been enrolled in this study. We measured serum B-type natriuretic peptide levels at the beginning and after completion of drug therapy for ductus occlusion.

Findings:

Mean±SD gestational age and weight was 31±1.9 weeks and 1680±350 gr, respectively. The peptide levels in the neonates with significant duct (n=13) were significantly higher than in those with insignificant duct (n=17) or no duct (n=30) (1667±821 pg/ml versus 667±666 and 309±171, respectively). The peptide level dropped significantly after ibuprofen administration in the neonates with significant PDA (n=13), (1667±1165 pg/ml to 429±386).

Conclusion:

At a cutoff point of 450 pg/ml, B-type natriuretic peptide level had a sensitivity of 92% and specificity of 87%, the negative predictive value of 98.5%, the positive likelihood ratio of 6.92 and the negative likelihood ratio of 0.089 for detecting significant patent duct. Levels below this can eliminate the need for echocardiography.     

Sigma S-Dependent Antioxidant Defense Protects Stationary-Phase Escherichia coli against the Bactericidal Antibiotic Gentamicin

Stationary-phase bacteria are important in disease. The σ^s-regulated general stress response helps them become resistant to disinfectants, but the role of σ^s in bacterial antibiotic resistance has not been elucidated. Loss of σ^s rendered stationary-phase Escherichia coli more sensitive to the bactericidal antibiotic gentamicin (Gm), and proteomic analysis suggested involvement of a weakened antioxidant defense. Use of the psfiA genetic reporter, 3′-(p-hydroxyphenyl) fluorescein (HPF) dye, and Amplex Red showed that Gm generated more reactive oxygen species (ROS) in the mutant. HPF measurements can be distorted by cell elongation, but Gm did not affect stationary-phase cell dimensions. Coadministration of the antioxidant N-acetyl cysteine (NAC) decreased drug lethality particularly in the mutant, as did Gm treatment under anaerobic conditions that prevent ROS formation. Greater oxidative stress, due to insufficient quenching of endogenous ROS and/or respiration-linked electron leakage, therefore contributed to the greater sensitivity of the mutant; infection by a uropathogenic strain in mice showed this to be the case also in vivo. Disruption of antioxidant defense by eliminating the quencher proteins, SodA/SodB and KatE/SodA, or the pentose phosphate pathway proteins, Zwf/Gnd and TalA, which provide NADPH for ROS decomposition, also generated greater oxidative stress and killing by Gm. Thus, besides its established mode of action, Gm also kills stationary-phase bacteria by generating oxidative stress, and targeting the antioxidant defense of E. coli can enhance its efficacy. Relevant aspects of the current controversy on the role of ROS in killing by bactericidal drugs of exponential-phase bacteria, which represent a different physiological state, are discussed.     

Transcatheter patch occlusion of ventricular septal defect in Down syndrome

Closure of perimembranous ventricular septal defects in patients with Down syndrome, either surgically or by Amplatzer occluders, carries a high risk of complete heart block. We report 5 closures using the transcatheter patch, a wireless bioabsorbable device without any reported heart block to date. The median defect size was 11 mm. Small devices were used in 4 patients and a medium size in 1. The patch was released after 48 hours in 3 patients and immediately in the other 2. Of the 5 patients, 3 were followed up for >5 years and 2 for 1 year. None of these patients had atrioventricular block during their follow-up. In conclusion, the transcatheter patch might be superior in terms of cardiac conduction system protection in patients with Down syndrome after ventricular septal defect closure.     

Plant-borne human contamination by fascioliasis

Contamination by fasciolids takes place through ingestion of metacercariae attached to vegetables. Experimental studies were performed with plant-made foods suggesting a role in human contamination in Iran and on the usefulness of potassium permanganate as a preventive tool for killing metacercariae attached to vegetables used in salads in Egypt. In the foods assayed, although viability decreases with time, a high percentage of the metacercariae were still alive 2 and 4 weeks after preparation. Infection of laboratory animals proved that metacercariae kept their infectivity. The 5-minute tests of potassium permanganate effects showed that metacercarial viability was not affected even at the very high doses of 300, 600, and 1,200 mg/L. Careful, subsequent washing of leaves and vegetables with water is therefore needed after its application. A review on similar studies performed with metacercariae belonging to fasciolid and other trematode species affecting humans is included.     

Closure of Interatrial Defects by Immediate-Release Patch

The Immediate-Release Patch is the newest version of the Transcatheter Patch, which is a bioabsorbable device for the closure of cardiac defects. Closure of 12 atrial septal defects and 1 fenestration was attempted using this device. Of the 13 devices used, 12 were implanted successfully (including that for the fenestration), whereas 1 device moved from the original position and was retrieved percutaneously. No other major adverse events occurred. After a median follow-up period of 11?months, trivial (??2-mm) residual shunts remained in two patients, and a significant residual defect (7?mm) remained in 1 patient. The major advantages of this device include its wirelessness, its bioabsorbablity, potential application for defects up to 30?mm using only three sizes, its easier retrieval, and its ability to occlude defects with a deficient rim and some ostium primum and sinus venosus type defects. In contrast to the metal devices, it is bulkier and has a different application method requiring operator familiarity, and it sometimes leaves residual shunts.