Etiologies,risk factors,and outcomes of bacterial cholangitis after living donor liver transplantation

The interpretation of bacterial cholangitis after liver transplantation (LT) remains vague, because the presence of bacteria in bile, namely bacteriobilia, does not necessarily indicate an active infection. We investigated the association between post-LT bacterial cholangitis and a variety of short- and long-term outcomes. Two-hundred-seventy-four primary adult-to-adult living donor LT recipients from 2008 to 2016 were divided into three groups according the presence or absence of bacteriobilia and clinical symptoms: (1) no bacteriobilia (N group), (2) asymptomatic bacteriobilia (B group), and (3) cholangitis (C group). The number of patients was by group: N, 161; B, 64; and C, 49. Donor age ≥?45 years (p?=?0.012), choledochojejunostomy (p?<?0.001), and post-LT portal hypertension (p?=?0.023) were independent risk factors for developing cholangitis. Survival analysis revealed that the C group had significantly worse short- and long-term graft survival. The C group was associated with an increased incidence of early graft loss (EGL) (p?<?0.001). While the frequency of readmission for recurrent cholangitis was significantly higher in both the B and C groups (p?<?0.001), late graft loss (LGL) due to chronic cholangitis was only commonly observed in the C group (p?=?0.002). Post-LT cholangitis could result in not only EGL but also chronic cholangitis and associated LGL.     

Whey protein intake after resistance exercise activates mTOR signaling in a dose-dependent manner in human skeletal muscle

Purpose

Protein ingestion after resistance exercise increases muscle protein synthesis (MPS) in a dose-dependent manner. However, the molecular mechanism(s) for the dose-dependency of MPS remains unclear. This study aimed to determine the dose response of mammalian target of rapamycin (mTOR) signaling in muscle with ingestion of protein after resistance exercise.

Methods

Fifteen male subjects performed four sets of six unilateral isokinetic concentric knee extensions. Immediately after exercise, eight subjects consumed water only. The other seven subjects, in a randomized-order crossover design, took either a 10 [3.6 g essential amino acids (EAA)] or 20 g (7.1 g EAA) solution of whey protein. Muscle biopsies from the vastus lateralis muscle were taken 30 min before and 1 h after resistance exercise. Phosphorylation of Akt (Ser473), mTOR (Ser2448), 4E-BP1 (Thr37/46), and S6K1 (Thr389) was measured by western blotting.

Results

Concentric knee extension exercise alone did not increase phosphorylation of Akt and mTOR 1 h after exercise, but ingesting protein after exercise significantly increased the phosphorylation of Akt and mTOR in a dose-dependent manner (P < 0.05). 4E-BP1 phosphorylation significantly decreased after resistance exercise (P < 0.05), but subjects who took 10 or 20 g of protein after exercise showed increased 4E-BP1 from post-exercise dephosphorylation (P < 0.05). S6K1 phosphorylation significantly increased after resistance exercise (P < 0.05), and 20 g of protein further increased S6K1 phosphorylation compared with ingestion of 10 g (P < 0.05).

Conclusions

These findings suggest that whey protein intake after resistance exercise activates mTOR signaling in a dose-dependent manner in untrained men.     

Theta frequency activity during rapid eye movement (REM) sleep is greater in people with resilience versus PTSD

Emotional memory consolidation has been associated with rapid eye movement (REM) sleep, and recent evidence suggests that increased electroencephalogram spectral power in the theta (4–8 Hz) frequency range indexes this activity. REM sleep has been implicated in posttraumatic stress disorder (PTSD) as well as in emotional adaption. In this cross-sectional study, thirty young healthy African American adults with trauma exposure were assessed for PTSD status using the Clinician Administered PTSD Scale. Two consecutive night polysomnographic (PSG) recordings were performed and data scored for sleep stages. Quantitative electroencephalographic spectral analysis was used to measure theta frequency components sampled from REM sleep periods of the second-night PSG recordings. Our objective was to compare relative theta power between trauma-exposed participants who were either resilient or had developed PTSD. Results indicated higher right prefrontal theta power during the first and last REM periods in resilient participants compared with participants with PTSD. Right hemisphere prefrontal theta power during REM sleep may serve as a biomarker of the capacity for adaptive emotional memory processing among trauma-exposed individuals.     

Carbon monoxide-bound hemoglobin-vesicles for the treatment of bleomycin-induced pulmonary fibrosis

Carbon monoxide (CO) has potent anti-inflammatory and anti-oxidant effects. We report herein on the preparation of a nanotechnology-based CO donor, CO-bound hemoglobin-vesicles (CO-HbV). We hypothesized that CO-HbV could have a therapeutic effect on idiopathic pulmonary fibrosis (IPF), an incurable lung fibrosis, that is thought to involve inflammation and the production of reactive oxygen species (ROS). Pulmonary fibril formation and respiratory function were quantitatively evaluated by measuring hydroxyproline levels and forced vital capacity, respectively, using a bleomycin-induced pulmonary fibrosis mice model. CO-HbV suppressed the progression of pulmonary fibril formation and improved respiratory function compared to saline and HbV. The suppressive effect of CO-HbV on pulmonary fibrosis can be attributed to a decrease in ROS generation by inflammatory cells, NADPH oxidase 4 and the production of inflammatory cells, cytokines and transforming growth factor-β in the lung. This is the first demonstration of the inhibitory effect of CO-HbV on the progression of pulmonary fibrosis via the anti-oxidative and anti-inflammatory effects of CO in the bleomycin-induced pulmonary fibrosis mice model. CO-HbV has the potential for use in the treatment of, not only IPF, but also a variety of other ROS and inflammation-related disorders.     

Soluble form of FGFR2 with S252W partially prevents craniosynostosis of the apert mouse model

Background: Apert syndrome (AS) is characterized by craniosynostosis, midfacial hypoplasia, and bony syndactyly. It is an autosomal dominantly inherited disease caused by point mutations (S252W or P253R) in fibroblast growth factor receptor (FGFR) 2. These mutations cause activation of FGFR2 depending on ligand binding. Recently, an AS mouse model, Fgfr2^+/S252W, showed phenotypes similar to those of AS patients. We previously reported that the soluble form of FGFR2^S252W (sFGFR2IIIc^S252W) efficiently inhibits enhanced osteoblastic differentiation caused by FGFR2 activation in AS in vitro, presumably because FGFs binding to FGFRs is interrupted. In this study, we developed Fgfr2^+/S252W (Ap) mice expressing the sFGFR2IIIc^S252W protein, and we investigated the effects of sFGFR2IIIc^S252W on AS‐like phenotypes. Results: In Ap mice, the coronal suture (CS) was fused prematurely at P1. In addition, the mice exhibited a widened interfrontal suture (IFS) with ectopic bone and thickened cartilage formation. In Fgfr2^+/S252W sFGFR2IIIc^S252W (Ap/Sol) mice, the CS was similar to that of wild‐type mice. Ap/Sol mice did not show any ectopic bone or cartilage formation in the IFS, but showed a wider IFS than that of the wild‐type mice. Conclusions: sFGFR2IIIc^S252W may partially prevent craniosynostosis in the Apert mouse model by affecting the CS and IFS in vivo. Developmental Dynamics 243:560–567, 2014. © 2013 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.     

Amino acid residues required for Gtr1p‐Gtr2p complex formation and its interactions with the Ego1p‐Ego3p complex and TORC1 components in yeast

The yeast Ras‐like GTPases Gtr1p and Gtr2p form a heterodimer, are implicated in the regulation of TOR complex 1 (TORC1) and play pivotal roles in cell growth. Gtr1p and Gtr2p bind Ego1p and Ego3p, which are tethered to the endosomal and vacuolar membranes where TORC1 functions are regulated through a relay of amino acid signaling interactions. The mechanisms by which Gtr1p and Gtr2p activate TORC1 remain obscure. We probed the interactions of the Gtr1p‐Gtr2p complex with the Ego1p‐Ego3p complex and TORC1 subunits. Mutations in the region (179–220 a.a.) following the nucleotide‐binding region of Gtr1p and Gtr2p abrogated their mutual interaction and resulted in a loss in function, suggesting that complex formation between Gtr1p and Gtr2p was indispensable for TORC1 function. A modified yeast two‐hybrid assay showed that Gtr1p‐Gtr2p complex formation is important for its interaction with the Ego1p‐Ego3p complex. GTP‐bound Gtr1p interacted with the region containing the HEAT repeats of Kog1p and the C‐terminal region of Tco89p. The GTP‐bound Gtr2p suppressed a Kog1p mutation. Our findings indicate that the interactions of the Gtr1p‐Gtr2p complex with the Ego1p‐Ego3p complex and TORC1 components Kog1p and Tco89p play a role in TORC1 function.     

Dynamics of genomic 5‐hydroxymethylcytosine during mouse oocyte growth

Recent studies of the demethylation process in murine zygotes have shown that 5‐methylcytosine (5mC) is first converted into 5‐hydroxymethylcytosine (5hmC) or further‐oxidized cytosines in the paternal genome by the maternal ten–eleven translocation 3 (TET3) enzyme. This process is crucial for normal embryogenesis, and our aim was to elucidate the effect of Tet3 on the maternal genome during female germ‐line development. Immunofluorescence analysis showed that 5hmC was clearly present in fully grown oocytes but not in nongrowing and early growth‐stage oocytes. The 5hmC in the maternal genome was clearly detectable in DNA methyltransferase 3‐like enzyme (Dnmt3L)‐null oocytes and their fertilized zygotes, although Dnmt3L is essential for DNA methylation in oocytes. An analysis using an enzyme digestion‐based method showed that 5hmC was present in LTR retrotransposons from the late growth period of oocytes. Quantitative RT‐PCR analysis showed that Tet3 expression was enhanced during oocyte growth and exhibited an approximately 40‐fold increase between nongrowing and fully grown oocytes. Our results show that 5hmC is generated since the oocyte growth stage, accompanied by up‐regulation of Tet3; 5hmC is located mainly in LTR retrotransposons, indicating that 5hmC generated in growth‐stage oocytes is responsible for genomewide demethylation after fertilization.     

s‐Afadin binds more preferentially to the cell adhesion molecules nectins than l‐afadin

l‐Afadin was originally purified from rat brain as an actin filament (F‐actin)‐binding protein that was homologous to the AF‐6 gene product. Concomitantly, s‐afadin that did not show an F‐actin‐binding capability was copurified with l‐afadin. Structurally, s‐afadin lacks the C‐terminal F‐actin‐binding domain but has two short sequences that were not present in l‐afadin. The properties and roles of l‐afadin have intensively been investigated, but those of s‐afadin have poorly been understood. We show here an additional difference in their biochemical properties other than binding to F‐actin between l‐afadin and s‐afadin. Both l‐afadin and s‐afadin bound to nectins, immunoglobulin‐like cell adhesion molecules, whereas s‐afadin more preferentially bound to nectins than l‐afadin. The PDZ domain of l‐afadin and s‐afadin was essential for their binding to nectin‐3. The dilute domain of l‐afadin negatively regulated its binding to nectin‐3, but the deletion of the C‐terminal F‐actin‐binding domain of l‐afadin did not increase the binding of l‐afadin to nectin‐3. These results indicate that the s‐afadin‐specific C‐terminal inserts may be involved in its preference of binding to nectin‐3 and raise the possibility that there are proteins other than nectins that more preferentially bind s‐afadin than l‐afadin.     

Epidermal growth factor receptor (EGFR) mutations in lung cancer: preclinical and clinical data

Lung cancer leads cancer-related mortality worldwide. Non-small-cell lung cancer (NSCLC), the most prevalent subtype of this recalcitrant cancer, is usually diagnosed at advanced stages, and available systemic therapies are mostly palliative. The probing of the NSCLC kinome has identified numerous nonoverlapping driver genomic events, including epidermal growth factor receptor (EGFR) gene mutations. This review provides a synopsis of preclinical and clinical data on EGFR mutated NSCLC and EGFR tyrosine kinase inhibitors (TKIs). Classic somatic EGFR kinase domain mutations (such as L858R and exon 19 deletions) make tumors addicted to their signaling cascades and generate a therapeutic window for the use of ATP-mimetic EGFR TKIs. The latter inhibit these kinases and their downstream effectors, and induce apoptosis in preclinical models. The aforementioned EGFR mutations are stout predictors of response and augmentation of progression-free survival when gefitinib, erlotinib, and afatinib are used for patients with advanced NSCLC. The benefits associated with these EGFR TKIs are limited by the mechanisms of tumor resistance, such as the gatekeeper EGFR-T790M mutation, and bypass activation of signaling cascades. Ongoing preclinical efforts for treating resistance have started to translate into patient care (including clinical trials of the covalent EGFR-T790M TKIs AZD9291 and CO-1686) and hold promise to further boost the median survival of patients with EGFR mutated NSCLC.