Probiotic use in pediatric kidney transplant recipients: What are current practices, and are they evidence-based? A pediatric nephrology research consortium study.

BACKGROUND: Probiotics are living microorganisms that may confer health benefits to their host if administered in sufficient quantities. However, data on the use of probiotics in transplant recipients are scarce. METHOD: This multi-center survey of pediatric nephrologists aimed to examine variations in practice regarding the use of probiotics in pediatric kidney transplant recipients. The survey was conducted via a 10-item questionnaire (developed in Survey Monkey) administered to pediatric nephrologists participating in the Pediatric Nephrology Research Consortium meeting in April 2023. RESULTS: Sixty-four pediatric nephrologists completed the survey. Twenty-seven (42.2%) respondents reported having prescribed probiotics to pediatric kidney transplant recipients. The primary reason for probiotic use was the treatment of antibiotic-associated diarrhea (n = 20), with other reasons including recurrent Clostridium difficile infection (n = 15), general gut health promotion (n = 12), recurrent urinary tract infections (n = 8), and parental request (n = 1). Of those who prescribed probiotics, 48.1% held them during periods of neutropenia and 14.8% during central venous line use. Of the 64 respondents, 20 reported the lack of safety data as a concern for using probiotics in kidney transplant recipients. CONCLUSION: Pediatric nephrologists are increasingly prescribing probiotics to pediatric kidney transplant recipients; nevertheless, substantial practice variations exist. The paucity of safety data is a significant deterrent to probiotic use in this population.

The relaxation behavior of supercooled and glassy imidacloprid.

Employing dielectric spectroscopy, oscillatory shear rheology, and calorimetry, the present work explores the molecular dynamics of the widely used insecticide imidacloprid above and below its glass transition temperature. In its supercooled liquid regime, the applied techniques yield good agreement regarding the characteristic structural (alpha) relaxation times of this material. In addition, the generalized Gemant-DiMarzio-Bishop model provides a good conversion between the frequency-dependent dielectric and shear mechanical responses in its viscous state, allowing for an assessment of imidacloprid's molecular hydrodynamic radius. In order to characterize the molecular dynamics in its glassy regime, we employ several approaches. These include the application of frequency-temperature superposition (FTS) to its isostructural dielectric and rheological responses as well as use of dielectric and calorimetric physical aging and the Adam-Gibbs-Vogel model. While the latter approach and dielectric FTS provide relaxation times that are close to each other, the other methods predict notably longer times that are closer to those reflecting a complete recovery of ergodicity. This seemingly conflicting dissimilarity demonstrates that the molecular dynamics of glassy imidacloprid strongly depends on its thermal history, with high relevance for the use of this insecticide as an active ingredient in technological applications.

Characterization of a 12-kilodalton rhodanese encoded by glpE of Escherichia coli and its interaction with thioredoxin.

Rhodaneses catalyze the transfer of the sulfane sulfur from thiosulfate or thiosulfonates to thiophilic acceptors such as cyanide and dithiols. In this work, we define for the first time the gene, and hence the amino acid sequence, of a 12-kDa rhodanese from Escherichia coli. Well-characterized rhodaneses are comprised of two structurally similar ca. 15-kDa domains. Hence, it is thought that duplication of an ancestral rhodanese gene gave rise to the genes that encode the two-domain rhodaneses. The glpE gene, a member of the sn-glycerol 3-phosphate (glp) regulon of E. coli, encodes the 12-kDa rhodanese. As for other characterized rhodaneses, kinetic analysis revealed that catalysis by purified GlpE occurs by way of an enzyme-sulfur intermediate utilizing a double-displacement mechanism requiring an active-site cysteine. The K(m)s for SSO(3)(2-) and CN(-) were 78 and 17 mM, respectively. The apparent molecular mass of GlpE under nondenaturing conditions was 22.5 kDa, indicating that GlpE functions as a dimer. GlpE exhibited a k(cat) of 230 s(-1). Thioredoxin 1 from E. coli, a small multifunctional dithiol protein, served as a sulfur acceptor substrate for GlpE with an apparent K(m) of 34 microM when thiosulfate was near its K(m), suggesting that thioredoxin 1 or related dithiol proteins could be physiological substrates for sulfurtransferases. The overall degree of amino acid sequence identity between GlpE and the active-site domain of mammalian rhodaneses is limited ( approximately 17%). This work is significant because it begins to reveal the variation in amino acid sequences present in the sulfurtransferases. GlpE is the first among the 41 proteins in COG0607 (rhodanese-related sulfurtransferases) of the database Clusters of Orthologous Groups of proteins (http://www.ncbi.nlm.nih.gov/COG/) for which sulfurtransferase activity has been confirmed.

Effects of chromium(VI) on some ion-dependent ATPases in gills, kidney and intestine of a coastal teleost Periophthalmus dipes.

The coastal teleost species, Periophthalmus dipes, commonly known as the mudskipper, was exposed to three sublethal concentrations (5, 10 and 15 mg/l) of potassium chromate for three exposure durations (2, 4 and 6 days). The study compares the dose- and duration-dependent effects of Cr(VI), as potassium chromate, on the ATPase systems in various organs of this fish species. In this study, effects of Cr(VI) stress on total ATPase, (Na+,K+)-ATPase, (Ca+2)-ATPase, (Mg+2)-ATPase, (Ca+2, HCO3-)-ATPase and (Mg+2,HCO3-)-ATPase in gills, kidney and intestine were estimated. A general dose- and duration-dependent inhibitory trend was observed. However, it is evident that exposure duration is more important then dose in the inhibition of the activity of the enzymes. At some concentrations, initial stimulation of the activity of some enzymes were also noticed. However, maximum inhibition was observed in higher Cr(VI) concentrations exposed for the longest time. It is possible that this inhibition of the ATPases by Cr(VI) blocked the active transport system of the gill epithelial as well as chloride cells, glomerular and epithelial cells of the tubules and thus altered the osmoregulatory mechanism of the fish. It appears that this heavy metal ion alters the membrane permeability of the intestinal epithelial cells and other layer of cells by altering the activity of ATPases, resulting in a breakdown of the active transport mechanism needed for the absorption of nutrients, ions and metabolites.

Mercuric chloride-induced inhibition of different ATPases in the intestine of mudskipper, Boleophthalmus dentatus.

This paper deals with the toxicity of mercuric chloride to different ATPases in the intestine of mudskipper (Boleophthalmus dentatus). Mudskippers were exposed to four sublethal concentrations of mercuric chloride for three durations. The specific activities of Na+, K(+)-ATPase, Ca(2+)-ATPase, Mg(2+)-ATPase, Ca2+, HCO3(-)-ATPase, and Mg2+, HCO3(-)-ATPase were estimated. There was linear inhibition of all the enzymes with increasing mercuric chloride concentration as well as exposure duration. The Na+,K(+)-ATPase was found to be the enzyme most affected, followed by other ion-dependent ATPases. Inhibition of all the enzymes indicates severe damage to the intestinal cells, resulting in a blockage of the transport of substances across the membrane.