Dual gold and photoredox catalysed C-H activation of arenes for aryl-aryl cross couplings.

A mild and fully catalytic aryl-aryl cross coupling via gold-catalysed C-H activation has been achieved by merging gold and photoredox catalysis. The procedure is free of stoichiometric oxidants and additives, which were previously required in gold-catalysed C-H activation reactions. Exploiting dual gold and photoredox catalysis confers regioselectivity via the crucial gold-catalysed C-H activation step, which is not present in the unselective photocatalysis-only counterpart.

AIMP2 Controls Intestinal Stem Cell Compartments and Tumorigenesis by Modulating Wnt/ß-Catenin Signaling.

Wnt/ß-catenin (CTNNB1) signaling is crucial for the proliferation and maintenance of intestinal stem cells (ISC), but excessive activation leads to ISC expansion and eventually colorectal cancer. Thus, negative regulators are required to maintain optimal levels of Wnt/ß-catenin signaling. Aminoacyl-tRNA synthetase-interacting multifunctional proteins (AIMP) function in protein synthesis, but have also been implicated in signaling cascades affecting angiogenesis, immunity, and apoptosis. In this study, we investigated the relationship between AIMP2 and Wnt/ß-catenin signaling in a murine model of intestinal homeostasis and tumorigenesis. Hemizygous deletion of Aimp2 resulted in enhanced Wnt/ß-catenin signaling, increased proliferation of cryptic epithelial cells, and expansion of ISC compartments. In an Apc(Min/+) background, Aimp2 hemizygosity increased adenoma formation. Mechanistically, AIMP2 disrupted the interaction between AXIN and Dishevelled-1 (DVL1) to inhibit Wnt/ß-catenin signaling by competing with AXIN. Furthermore, AIMP2 inhibited intestinal organoid formation and growth by suppressing Wnt/ß-catenin signaling in an Aimp2 gene dosage-dependent manner. Collectively, our results showed that AIMP2 acts as a haploinsufficient tumor suppressor that fine-tunes Wnt/ß-catenin signaling in the intestine, illuminating the regulation of ISC abundance and activity. Cancer Res; 76(15); 4559-68. ©2016 AACR.

Enantioselective oxidative boron Heck reactions.

This review highlights the use of the oxidative boron Heck reaction in enantioselective Heck-type couplings. The enantioselective oxidative boron Heck reaction overcomes several limitations of the traditional Pd(0)-catalysed Heck coupling and has subsequently allowed for intermolecular couplings of challenging systems such as cyclic enones, acyclic alkenes, and even site selectively on remote alkenes.

Oxidative Heck desymmetrisation of 2,2-disubstituted cyclopentene-1,3-diones.

Oxidative Heck couplings have been successfully developed for 2,2-disubstituted cyclopentene-1,3-diones. The direct coupling onto the 2,2-disubstituted cyclopentene-1,3-dione core provides a novel expedient way of enantioselectively desymmetrising all-carbon quaternary centres.

Dehydrative thiolation of allenols: indium vs gold catalysis.

Intermolecular additions of thiols to allenols via formal S(N)2' selectivity to produce functionalized dienes are described. Although this dehydrative reaction was initially developed using gold(I) catalysis, indium(III) proves to be a far superior catalyst in terms of selectivity and substrate scope.

Graft function measured by transient elastography in living donor liver transplantation: preliminary.

INTRODUCTION: Liver stiffness measurements (LSMs) using transient elastography (TE) provide a noninvasive means to assess liver fibrosis that correlate with hepatic cholestasis. However, few studies have examined the correlation of TE to obtain LSMs with perioperative clinical and laboratory parameters in living donor liver transplantation (LDLT). PATIENTS AND METHODS: We retrospectively reviewed forty-eight subjects who underwent LDLT between November 2010 and October 2012. All donors and recipients underwent TE, abdominal computed tomography (CT), and biochemical tests within 1 month before and at 1 week after transplantation. Using a cut-off LSM of 7.5 kPa, which we arbitrarily assigned to be indicative of significant fibrosis, we divided our study population into ≤7.5 kPa (group L; n = 15, 31.3%) versus >7.5 kPa; (group H; n = 33, 68.8%). RESULTS: Pretransplantation serum total bilirubin, international normalized ratio, and Model for End-stage Liver Disease scores of recipients were significantly higher in group H than group L. Regarding the pretransplantation donor characteristics, the graft-recipient weight ratio was significantly smaller among those in group H (P = .039). In addition, the post-transplantation 1-week serum total bilirubin level was significantly higher in group H (2.3 mg/dL versus 1.2 mg/dL, P = .015), although neither biliary complications norhepatic congestion was identified by abdominal CT. Among the 1-week post-transplantation laboratory findings, only total bilirubin positively correlated with LSM (P = .044). CONCLUSIONS: This pilot study suggested that a high LSM after LDLT suggests intrahepatic cholestasis and portal hypercirculation in the graft, irrespective of liver fibrosis, outflow obstruction, or biliary obstruction.

Should oxyhaemoglobin saturation be monitored continuously during the 6-minute walk test?

Guidelines for conducting the 6-minute walk test (6MWT) indicate that oxyhaemoglobin saturation (SpO( 2)) should not be monitored constantly during the test. The aim of this study was to determine whether the nadir SpO(2) differs from the end-6MWT SpO(2) in patients with chronic respiratory disease. A total of 86 subjects underwent the 6MWT according to a standardized protocol with continuous monitoring of SpO(2) by pulse oximeter. Comparison of nadir SpO(2) and end SpO(2) was made and the proportion of subjects with important desaturation according to each measure was determined. The effect of resting during the 6MWT on the likelihood of a significant difference between nadir and end SpO(2) was evaluated. A total of 29 subjects with chronic obstructive pulmonary disease (COPD; mean [SD] forced expiratory volume in 1 second [FEV(1)] 51[21] % predicted) and 57 with interstitial lung disease (ILD; TLCO 49[18] % predicted) were studied. Nadir SpO(2) was slightly lower than end-test SpO(2) (median 87% vs. 88%, p < 0.001) with differences ranging from 1% to 10%. Those who rested during the test (n = 14) were more likely to have a significant difference between nadir SpO(2) and end SpO(2) (p = 0.04). End SpO(2) did not accurately identify desaturation in 21% of subjects. No differences between COPD and ILD were observed. For most patients with chronic respiratory disease, the end SpO(2) and the nadir SpO( 2) are similar during the 6MWT. However, the end SpO(2) does not give an accurate estimate of nadir SpO(2) in patients who rest. Consideration should be given to the constant monitoring of SpO(2) during the 6MWT.

Cancer-associated splicing variant of tumor suppressor AIMP2/p38: pathological implication in tumorigenesis.

Although ARS-interacting multifunctional protein 2 (AIMP2, also named as MSC p38) was first found as a component for a macromolecular tRNA synthetase complex, it was recently discovered to dissociate from the complex and work as a potent tumor suppressor. Upon DNA damage, AIMP2 promotes apoptosis through the protective interaction with p53. However, it was not demonstrated whether AIMP2 was indeed pathologically linked to human cancer. In this work, we found that a splicing variant of AIMP2 lacking exon 2 (AIMP2-DX2) is highly expressed by alternative splicing in human lung cancer cells and patient's tissues. AIMP2-DX2 compromised pro-apoptotic activity of normal AIMP2 through the competitive binding to p53. The cells with higher level of AIMP2-DX2 showed higher propensity to form anchorage-independent colonies and increased resistance to cell death. Mice constitutively expressing this variant showed increased susceptibility to carcinogen-induced lung tumorigenesis. The expression ratio of AIMP2-DX2 to normal AIMP2 was increased according to lung cancer stage and showed a positive correlation with the survival of patients. Thus, this work identified an oncogenic splicing variant of a tumor suppressor, AIMP2/p38, and suggests its potential for anti-cancer target.

Insulin-induced drug eruptions and reliability of skin tests.

Allergic reaction to insulin preparations seemed to have decreased since the introduction of contaminant-free, human preparations. The role of protamine sulfate in decreasing the prevalence of allergy is unclear. This study examines the causative components of insulin allergy along with the value of skin tests for diagnosis. Eleven patients with insulin allergy and 53 patients receiving insulin but without an insulin allergy were included as controls. Intradermal skin tests were conducted using preparations containing various concentrations of insulin [Neutral protamine Hagedorn (NPH) insulin, regular insulin (RI)] and protamine sulfate. Of the 11 patients studied, 3 had anaphylaxis and 8 displayed localized reactions. All of the patients reacted positively during skin testing. Five patients showed positive intradermal skin test reactions to protamine sulfate, and 4 reacted to insulin. Two patients that were not tested with protamine sulfate reacted positively to NPH insulin. In the case of protamine sulfate, 4 patients with localized symptoms displayed positive reactions at concentrations of 10 microg/ml, 3 microg/ml or 0.3 microg/ml. One patient with anaphylaxis reacted positively to a concentration as low as 0.03 ng/ml. In the case of insulin protein, 3 patients reacted positively to a 100-fold dilution (1 UI/ml). Eight of the 53 controls experienced pruritus and/or skin lesions. However, none of the controls reacted at a concentration of NPH insulin of less than 10 U/ml or to protamine sulfate at less than 30 microg/ml. Allergic reactions to protamine sulfate are common and should not be ignored. This study shows a good correlation between clinical manifestations and skin test reactions for insulin allergy.

A larger pool of ozone-forming carbon compounds in urban atmospheres

Volatile organic compounds play a central role in the processes that generate both urban photochemical smog and tropospheric ozone. For successful and accurate prediction of these pollution episodes, identification of the dominant reactive species within the volatile organic carbon pool is needed. At present, lack of resolution inherent in single-column chromatographic analysis limits such a detailed chemical characterization of the complex urban atmosphere. Here we present an improved method of peak deconvolution from double-column (orthogonal) gas chromatography. This has enabled us to isolate and classify more than 500 chemical species of volatile organic compounds in urban air, including over 100 multi-substituted monoaromatic and volatile oxygenated hydrocarbons. We suggest that previous assessments of reactive carbon species may therefore have underestimated the contribution made by volatile organic compounds to urban pollution, particularly for compounds with more than six carbon atoms. Incorporating these species in predictive models should greatly improve our understanding of photochemical ozone yields and the formation of harmful secondary organic aerosols.