Acute kidney injury is associated with subsequent infection in neonates after the Norwood procedure: a retrospective chart review

Background: Acute kidney injury (AKI) and infection are common complications after pediatric cardiac surgery. No pediatric study has evaluated for an association between postoperative AKI and infection. The objective of this study was to determine if AKI in neonates after cardiopulmonary bypass was associated with the development of a postoperative infection. Methods: We performed a single center retrospective chart review from January 2009 to December 2015 of neonates (age ≤ 30 days) undergoing the Norwood procedure. AKI was defined by the modified neonatal Kidney Disease Improving Global outcomes serum creatinine criteria using (1) measured serum creatinine and (2) creatinine corrected for fluid balance on postoperative days 1-4. Infection, (culture positive or presumed), must have occurred after a diagnosis of AKI and within 60 days of surgery. Results: Ninety-five patients were included, of which postoperative infection occurred in 42 (44%). AKI occurred in 38 (40%) and 42 (44%) patients by measured serum creatinine and fluid overload corrected creatinine, respectively, and was most commonly diagnosed on postoperative day 2. The median time to infection from the time of surgery and AKI was 7 days (IQR 5-14 days) and 6 days (IQR 3-13 days), respectively. After adjusting for confounders, the odds of a postoperative infection were 3.64 times greater in patients with fluid corrected AKI (95% CI, 1.36-9.75; p = 0.01). Conclusions: Fluid corrected AKI was independently associated with the development of a postoperative infection. These findings support the notion that AKI is an immunosuppressed state that increases the risk of infection

Studying the Salt Dependence of the Binding of σ70 and σ32 to Core RNA Polymerase Using Luminescence Resonance Energy Transfer

The study of protein-protein interactions is becoming increasingly important for understanding the regulation of many cellular processes. The ability to quantify the strength with which two binding partners interact is desirable but the accurate determination of equilibrium binding constants is a difficult process. The use of Luminescence Resonance Energy Transfer (LRET) provides a homogeneous binding assay that can be used for the detection of protein-protein interactions. Previously, we developed an LRET assay to screen for small molecule inhibitors of the interaction of σ70 with theβ' coiled-coil fragment (amino acids 100–309). Here we describe an LRET binding assay used to monitor the interaction of E. coli σ70 and σ32 with core RNA polymerase along with the controls to verify the system. This approach generates fluorescently labeled proteins through the random labeling of lysine residues which enables the use of the LRET assay for proteins for which the creation of single cysteine mutants is not feasible. With the LRET binding assay, we are able to show that the interaction of σ70 with core RNAP is much more sensitive to NaCl than to potassium glutamate (KGlu), whereas the σ32 interaction with core RNAP is insensitive to both salts even at concentrations >500 mM. We also find that the interaction of σ32 with core RNAP is stronger than σ70 with core RNAP, under all conditions tested. This work establishes a consistent set of conditions for the comparison of the binding affinities of the E.coli sigma factors with core RNA polymerase. The examination of the importance of salt conditions in the binding of these proteins could have implications in both in vitro assay conditions and in vivo function

The Potential and Challenges of Nanopore Sequencing

A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of ‘third generation’ instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h.Molecular and Cellular BiologyPhysic

Genome-wide association study identifies multiple risk loci for renal cell carcinoma

Previous genome-wide association studies (GWAS) have identified six risk loci for renal cell carcinoma (RCC). We conducted a meta-analysis of two new scans of 5,198 cases and 7,331 controls together with four existing scans, totalling 10,784 cases and 20,406 controls of European ancestry. Twenty-four loci were tested in an additional 3,182 cases and 6,301 controls. We confirm the six known RCC risk loci and identify seven new loci at 1p32.3 (rs4381241, P=3.1 × 10−10), 3p22.1 (rs67311347, P=2.5 × 10−8), 3q26.2 (rs10936602, P=8.8 × 10−9), 8p21.3 (rs2241261, P=5.8 × 10−9), 10q24.33-q25.1 (rs11813268, P=3.9 × 10−8), 11q22.3 (rs74911261, P=2.1 × 10−10) and 14q24.2 (rs4903064, P=2.2 × 10−24). Expression quantitative trait analyses suggest plausible candidate genes at these regions that may contribute to RCC susceptibility

On-Chip Contactless Four-Electrode Conductivity Detection for Capillary Electrophoresis Devices

In this contribution, a capillary electrophoresis microdevice with an integrated on-chip contactless fourelectrode conductivity detector is presented. A 6-cm-long, 70-µm-wide, and 20-µm-deep channel was etched in a glass substrate that was bonded to a second glass substrate in order to form a sealed channel. Four contactless electrodes (metal electrodes covered by 30-nm silicon carbide) were deposited and patterned on the second glass substrate for on-chip conductivity detection. Contactless conductivity detection was performed in either a two-or a four-electrode configuration. Experimental results confirmed the improved characteristics of the fourelectrode configuration over the classical two-electrode detection setup. The four-electrode configuration allows for sensitive detection for varying carrier-electrolyte background conductivity without the need for adjustment of the measurement frequency. Reproducible electrophoretic separations of three inorganic cations (K + , Na + , Li + ) and six organic acids are presented. Detection as low as 5 µM for potassium was demonstrated. In the development and optimization of miniaturized analytical systems, a delicate combination of science and technology originating from microelectronic device fabrication, electrical engineering, and analytical chemistry is essential. In this multidisciplinary field, microtechnology experts combine the demands from analytical chemistry and electronic instrumentation in the design and fabrication of novel analytical devices. 1,2 Chemical analysis systems, such as high-performance liquid chromatography (HPLC) or capillary electrophoresis (CE), always consist of the combination of a separation and a detection system. For separation, CE or CE-based separation techniques are highly suitable for implementation on the microchip format. Electrokinetic control of fluid transport eliminates the need for external components such as pumps and valves. The separation efficiency is relatively independent of the separation path length and is, therefore, more compatible with miniaturization than, for instance, chromatographic techniques. As far as detection is concerned, laser-induced fluorescence (LIF) is, at present, the most widely used detection technique in miniaturized analysis systems because of its high sensitivity. The drawbacks of LIF are its limited compatibility with miniaturization and on-chip integration and the requirement for labeling of most (bio) chemically relevant compounds. External devices such as the relatively large laser and the photodetector system strongly prohibit further miniaturization. The development of alternative detection methods compatible with miniaturization and full onchip integration is highly desirable. Since electrode deposition is a well-established process in microfabrication, the implementation of detection techniques utilizing integrated electrodes has become an attractive approach. Successful coupling of conventional CE with potentiometry, 3 amperometry, 4,5 and conductometry 6-10 has been reported in the literature. In addition, both amperometric and potentiometric detection were also implemented in chip-based CE systems. [11][12][13] The primary advantage of amperometric and potentiometric detection over conductivity detection is the high selectivity induced by the electrochemical reactions that take place at the electrode surface. Only electrochemically active compounds * Corresponding author: (tel) +31 (0) 15 278 6518; (fax) +31 (0) 15 278 5755