Incidence and Risk Factors for Cytomegalovirus Infection in Patients With Kidney Transplantation: A Single-Center Experience

BACKGROUND

Cytomegalovirus (CMV) infection is deemed to be a major cause of morbidity and mortality in patients after kidney transplantation. The purpose of this study was to analyze the incidence of CMV infection and risk factors for CMV infection in our center, to help in determination of its impact on the kidney function in this patient population, and to provide new ideas for the prevention and treatment of CMV infection.

METHODS

A total of 319 kidney transplant recipients from our center were studied between January 2000 and December 2015. The CMV viral load in each kidney transplant patients was monitored with the use of CMV quantitative nucleic acid testing (CMV-QNAT). Laboratory data and other medical records were also collected.

RESULTS

The incidence of CMV infection was 8.8% in our studied patients. The patients within 3 to 6 months and 5 to 10 years after transplantation had a higher risk of CMV infection. CMV infection was probably correlated with lower white blood cell counts but elevated hemoglobin, serum creatinine, blood urea nitrogen, potassium, and estimated glomerular filtration rate (eGFR). Anti-CMV immunoglobulin (Ig)G and history of allograft rejection were also associated with CMV infection. In multivariate regression analysis, white blood cells, eGFR, anti-CMV IgG, and history of allograft rejection were the independent risk factors associated with CMV infection in kidney transplantation patients.

CONCLUSIONS

CMV infection was an important complication after kidney transplantation, particularly in these patients with allograft impairment.

Characterization and application of a self-aspirating electrospray source with pneumatic-assisted ionization

A single gas-assisted electrospray ion source developed for ambient mass spectrometry is introduced in this paper. Simultaneous self-aspiration and electrospray could be achieved by using a constant sheath gas flow supplied from a mini air pump. A gas dynamic study of the spray module is carried out for structural optimization. The entire device exhibits a simplified design and has been systematically characterized through both simulated and experimental investigations. According to the results, the ion source exhibited satisfactory stability and the ability for quantitative operation in routine electrospray ionization mass spectrometry. Furthermore, the ion source can be operated as a desorption electrospray ionization source to perform direct desorption/ionization of the solid samples. The versatile source described here appears to provide a practical approach to perform ambient mass spectrometry analysis with unrestricted sampling operation, and the extensive gas dynamic studies together with the experimental characterization are believed to be helpful in building self-aspirating spray devices. Copyright © 2017 John Wiley & Sons, Ltd.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Abstract 4377: AKT positively regulates Rho-GTP by attenuating the GAP activity of the DLC1 tumor suppressor: a mechanistic study with translational implications

Many human cancers have high AKT activity and constitutive up-regulation of Rho-GTP, which is a major factor in the neoplastic process, but AKT is not known to regulate Rho-GTP. In this study, we show that AKT positively regulates Rho-GTP by directly phosphorylating tumor suppressor DLC1 and attenuating the Rho-GAP activity of DLC1, which catalyzes the conversion of active Rho-GTP to inactive Rho-GDP. Interestingly, AKT was found to increase Rho-GTP and its downstream activities in DLC1-positive cancer lines whether the DLC1 was endogenous or transfected, but not in DLC1-negative lines. Similarly, when epithelial cell lines were stimulated with EGF, they activated AKT, which increased Rho-GTP in a DLC1-dependent manner. Three Serines (S298, S329, S567) in DLC1 have AKT consensus motifs and were phosphorylated by AKT in vitro and in vivo. Their phosphorylation attenuated the Rho-GAP and tumor suppressor activities of DLC1 - including decreased cell migration, focal adhesion turnover, anchorage-independent growth, and tumor growth in mice - as did the combined phosphomimetic mutant DLC1-3D. By contrast, the combined Serine to Alanine mutant DLC1-3A was even more active than wild type DLC1 (DLC1-WT). Remarkably, an AKT inhibitor stimulated the tumor suppressor and Rho-GAP activities of DLC1-WT, but did not influence DLC1-3A or DLC1-3D. The N-terminal half of DLC1 (amino acids 1-600) bound the DLC1 Rho-GAP domain (amino acids 609-878), as determined by in vivo complex formation and by microscale thermophoresis, which measures protein interactions in close-to-native conditions. There was increased binding and decreased Rho-GAP activity when the three Serines in the N-terminus were phosphorylated or carried the 3D mutations. Conversely, there was decreased binding and increased Rho-GAP activity when the Serines were not phosphorylated or carried the 3A mutations. In a xenograft mouse model, AKT inhibitor treatment of DLC1-positive palpable tumors reduced their size, their Rho-GTP level, and their Rho-dependent signaling, but did not affect these three parameters in isogenic DLC1-negative tumors. Similarly, in the MMTV-PyMT breast cancer model, which had high AKT activity, high Rho-GTP, and expressed DLC1, an AKT inhibitor reduced the size of palpable tumors, and reduced Rho-GTP and its downstream signaling. AKT inhibition reduced DLC1 phosphorylation in both tumor models. We conclude: AKT can increase Rho-GTP by phosphorylating three N-terminal Serines in DLC1, which attenuates its Rho-GAP and tumor suppressor functions; the N-terminus of DLC1 is an auto-inhibitory domain that reversibly binds the Rho-GAP domain; AKT attenuates DLC1 functions by phosphorylating the Serines in the N-terminus, which increases its binding the Rho-GAP domain; and AKT inhibition has greater anti-tumor activity in DLC1-positive tumors than in DLC1-negative tumors.

Citation Format: Brajendra K. Tripathi, Tiera Grant, Philipp Mertins, Xiaolan Qian, Dunrui Wang, Alex G. Papageorge, Steven A. Carr, Douglas R. Lowy. AKT positively regulates Rho-GTP by attenuating the GAP activity of the DLC1 tumor suppressor: a mechanistic study with translational implications. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4377.

LD Motif Recognition by Talin: Structure of the Talin-DLC1 Complex

Cell migration requires coordination between integrin-mediated cell adhesion to the extracellular matrix and force applied to adhesion sites. Talin plays a key role in coupling integrin receptors to the actomyosin contractile machinery, while deleted in liver cancer 1 (DLC1) is a Rho GAP that binds talin and regulates Rho, and therefore actomyosin contractility. We show that the LD motif of DLC1 forms a helix that binds to the four-helix bundle of the talin R8 domain in a canonical triple-helix arrangement. We demonstrate that the same R8 surface interacts with the paxillin LD1 and LD2 motifs. We identify key charged residues that stabilize the R8 interactions with LD motifs and demonstrate their importance in vitro and in cells. Our results suggest a network of competitive interactions in adhesion complexes that involve LD motifs, and identify mutations that can be used to analyze the biological roles of specific protein-protein interactions in cell migration.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction (3)He(↑)(e,e')

We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97  GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97  GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.

Acquiring Kupffer cells in mice using a MACS-based method

OBJECTIVE

This study sought to establish a new method to isolate Kupffer cells (KCs) by magnetic activated cell sorting (MACS).

METHODS

Nonparenchymal cells were acquired from C57BL/6 mice livers by a perfusion system in vivo and then stained with F4/80(+) fluorescein isothiocyanate and CD11c(-) phycoerythrin antibodies. After incubating with immunomagnetic beads, F4/80(+)CD11c(-) KCs were obtained by MACS selection. The purity was evaluated by flow cytometry, and the morphological features and vitality were analyzed in in vitro cultures.

RESULTS

Compared with traditional methods, acquiring KCs by MACS was characterized by economy, efficiency, and high purity. The F4/80(+)CD11c(-) KCs cultured in vitro also showed the typical adherent shape and excellent phagocytic ability.

CONCLUSIONS

With the 2-step method using immunomagnetic beads, we provide a new method by which KCs can be obtained from mouse liver with high purity and distinct phenotype of F4/80(+) CD.