A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Calbindin D(9k) knockout mice are indistinguishable from wild-type mice in phenotype and serum calcium level

Since the discovery of calbindin D(9k), its role in intestinal calcium absorption has remained unsettled. Further, a wide distribution of calbindin D(9k) among tissues has argued for its biological importance. We discovered a frameshift deletion in the calbindin D(9k) gene in an ES cell line, E14.1, that originated from 129/OlaHsd mice. We produced mice with the mutant calbindin D(9k) gene by injecting the E14.1 ES cell subline into the C57BL/6 host blastocysts and proved that these mice lack calbindin D(9k) protein. Calbindin D(9k) knockout mice were indistinguishable from wild-type mice in phenotype, were able to reproduce, and had normal serum calcium levels. Thus, calbindin D(9k) is not required for viability, reproduction, or calcium homeostasis

Catalysis of cis/trans isomerization in native HIV-1 capsid by human cyclophilin A

Packaging of cyclophilin A (CypA) into HIV-1 virions is essential for efficient replication; however, the reason for this is unknown. Incorporation is mediated through binding to the Gly-89–Pro-90 peptide bond of the N-terminal domain of HIV-1 capsid (CA(N)). Despite the fact that CypA is a peptidyl-prolyl cis/trans isomerase, catalytic activity on CA(N) has not been observed previously. We show here, using NMR exchange spectroscopy, that CypA does not only bind to CA(N) but also catalyzes efficiently the cis/trans isomerization of the Gly-89–Pro-90 peptide bond. In addition, conformational changes in CA(N) distal to the CypA binding loop are observed on CypA binding and catalysis. The results provide experimental evidence for efficient CypA catalysis on a natively folded and biologically relevant protein substrate