Physikalische Chemie 2012

Zeitaufgelöste Experimente mit Freie-Elektronen-Lasern filmen chemische Reaktionen auf der Femto- und Pikosekundenskala mit atomarer Ortsauflösung. Wasserstoffbrückenbindungen brechen und ‧knüpfen auf einer Zeitskala von Pikosekunden. Mit zweidimensionaler Infrarotspektroskopie lässt sich die damit verbundene strukturelle Dynamik in Echtzeit beobachten

Mutational signatures are jointly shaped by DNA damage and repair.

Funder: Biotechnology and Biological Sciences Research Council East of Scotland Bioscience Doctoral Training Partnership Ph.D. studentshipFunder: Korean Institute for Basic Science, IBS-R022-A1-2019Cells possess an armamentarium of DNA repair pathways to counter DNA damage and prevent mutation. Here we use C. elegans whole genome sequencing to systematically quantify the contributions of these factors to mutational signatures. We analyse 2,717 genomes from wild-type and 53 DNA repair defective backgrounds, exposed to 11 genotoxins, including UV-B and ionizing radiation, alkylating compounds, aristolochic acid, aflatoxin B1, and cisplatin. Combined genotoxic exposure and DNA repair deficiency alters mutation rates or signatures in 41% of experiments, revealing how different DNA alterations induced by the same genotoxin are mended by separate repair pathways. Error-prone translesion synthesis causes the majority of genotoxin-induced base substitutions, but averts larger deletions. Nucleotide excision repair prevents up to 99% of point mutations, almost uniformly across the mutation spectrum. Our data show that mutational signatures are joint products of DNA damage and repair and suggest that multiple factors underlie signatures observed in cancer genomes

Ectonucleotidases in Müller glial cells of the rodent retina: Involvement in inhibition of osmotic cell swelling

Extracellular nucleotides mediate glia-to-neuron signalling in the retina and are implicated in the volume regulation of retinal glial (Müller) cells under osmotic stress conditions. We investigated the expression and functional role of ectonucleotidases in Müller cells of the rodent retina by cell-swelling experiments, calcium imaging, and immuno- and enzyme histochemistry. The swelling of Müller cells under hypoosmotic stress was inhibited by activation of an autocrine purinergic signalling cascade. This cascade is initiated by exogenous glutamate and involves the consecutive activation of P2Y1 and adenosine A1 receptors, the action of ectoadenosine 5′-triphosphate (ATP)ases, and a nucleoside-transporter-mediated release of adenosine. Inhibition of ectoapyrases increased the ATP-evoked calcium responses in Müller cell endfeet. Müller cells were immunoreactive for nucleoside triphosphate diphosphohydrolases (NTPDase)2 (but not NTPDase1), ecto-5′-nucleotidase, P2Y1, and A1 receptors. Enzyme histochemistry revealed that ATP but not adenosine 5′-diphosphate (ADP) is extracellularly metabolised in retinal slices of NTPDase1 knockout mice. NTPDase1 activity and protein is restricted to blood vessels, whereas activity of alkaline phosphatase is essentially absent at physiological pH. The data suggest that NTPDase2 is the major ATP-degrading ectonucleotidase of the retinal parenchyma. NTPDase2 expressed by Müller cells can be implicated in the regulation of purinergic calcium responses and cellular volume

LICC: L-BLP25 in patients with colorectal carcinoma after curative resection of hepatic metastases--a randomized, placebo-controlled, multicenter, multinational, double-blinded phase II trial

Background: 15-20% of all patients initially diagnosed with colorectal cancer develop metastatic disease and surgical resection remains the only potentially curative treatment available. Current 5-year survival following R0-resection of liver metastases is 28-39%, but recurrence eventually occurs in up to 70%. To date, adjuvant chemotherapy has not improved clinical outcomes significantly. The primary objective of the ongoing LICC trial (L-BLP25 In Colorectal Cancer) is to determine whether L-BLP25, an active cancer immunotherapy, extends recurrence-free survival (RFS) time over placebo in colorectal cancer patients following R0/R1 resection of hepatic metastases. L-BLP25 targets MUC1 glycoprotein, which is highly expressed in hepatic metastases from colorectal cancer. In a phase IIB trial, L-BLP25 has shown acceptable tolerability and a trend towards longer survival in patients with stage IIIB locoregional NSCLC. Methods: This is a multinational, phase II, multicenter, randomized, double-blind, placebo-controlled trial with a sample size of 159 patients from 20 centers in 3 countries. Patients with stage IV colorectal adenocarcinoma limited to liver metastases are included. Following curative-intent complete resection of the primary tumor and of all synchronous/metachronous metastases, eligible patients are randomized 2:1 to receive either L-BLP25 or placebo. Those allocated to L-BLP25 receive a single dose of 300 mg/m2 cyclophosphamide (CP) 3 days before first L-BLP25 dose, then primary treatment with s.c. L-BLP25 930 mug once weekly for 8 weeks, followed by s.c. L-BLP25 930 mug maintenance doses at 6-week (years 1&2) and 12-week (year 3) intervals unless recurrence occurs. In the control arm, CP is replaced by saline solution and L-BLP25 by placebo. Primary endpoint is the comparison of recurrence-free survival (RFS) time between groups. Secondary endpoints are overall survival (OS) time, safety, tolerability, RFS/OS in MUC-1 positive cancers. Exploratory immune response analyses are planned. The primary endpoint will be assessed in Q3 2016. Follow-up will end Q3 2017. Interim analyses are not planned. Discussion: The design and implementation of such a vaccination study in colorectal cancer is feasible. The study will provide recurrence-free and overall survival rates of groups in an unbiased fashion. Trial Registration EudraCT Number 2011-000218-2

Accuracy of Patient Health Questionnaire-9 (PHQ-9) for screening to detect major depression: individual participant data meta-analysis

Objective: To determine the accuracy of the Patient Health Questionnaire-9 (PHQ-9) for screening to detect major depression. Design: Individual participant data meta-analysis. Data sources: Medline, Medline In-Process and Other Non-Indexed Citations, PsycINFO, and Web of Science (January 2000-February 2015). Inclusion criteria: Eligible studies compared PHQ-9 scores with major depression diagnoses from validated diagnostic interviews. Primary study data and study level data extracted from primary reports were synthesized. For PHQ-9 cut-off scores 5-15, bivariate random effects meta-analysis was used to estimate pooled sensitivity and specificity, separately, among studies that used semistructured diagnostic interviews, which are designed for administration by clinicians; fully structured interviews, which are designed for lay administration; and the Mini International Neuropsychiatric (MINI) diagnostic interviews, a brief fully structured interview. Sensitivity and specificity were examined among participant subgroups and, separately, using meta-regression, considering all subgroup variables in a single model. Results: Data were obtained for 58 of 72 eligible studies (total n=17 357; major depression cases n=2312). Combined sensitivity and specificity was maximized at a cut-off score of 10 or above among studies using a semistructured interview (29 studies, 6725 participants; sensitivity 0.88, 95% confidence interval 0.83 to 0.92; specificity 0.85, 0.82 to 0.88). Across cut-off scores 5-15, sensitivity with semistructured interviews was 5-22% higher than for fully structured interviews (MINI excluded; 14 studies, 7680 participants) and 2-15% higher than for the MINI (15 studies, 2952 participants). Specificity was similar across diagnostic interviews. The PHQ-9 seems to be similarly sensitive but may be less specific for younger patients than for older patients; a cut-off score of 10 or above can be used regardless of age.. Conclusions: PHQ-9 sensitivity compared with semistructured diagnostic interviews was greater than in previous conventional meta-analyses that combined reference standards. A cut-off score of 10 or above maximized combined sensitivity and specificity overall and for subgroups. Registration: PROSPERO CRD42014010673

Probability of major depression diagnostic classification using semi-structured vs. fully structured diagnostic interviews

Background: Different diagnostic interviews are used as reference standards for major depression classification in research. Semi-structured interviews involve clinical judgement, whereas fully structured interviews are completely scripted. The Mini International Neuropsychiatric Interview (MINI), a brief fully structured interview, is also sometimes used. It is not known whether interview method is associated with probability of major depression classification. Aims: To evaluate the association between interview method and odds of major depression classification, controlling for depressive symptom scores and participant characteristics. Method: Data collected for an individual participant data meta-analysis of Patient Health Questionnaire-9 (PHQ-9) diagnostic accuracy were analyzed. Binomial Generalized Linear Mixed Models were fit. Results: 17,158 participants (2,287 major depression cases) from 57 primary studies were analyzed. Among fully structured interviews, odds of major depression were higher for the MINI compared to the Composite International Diagnostic Interview (CIDI) [OR (95% CI) = 2.10 (1.15-3.87)]. Compared to semi-structured interviews, fully structured interviews (MINI excluded) were non-significantly more likely to classify participants with low-level depressive symptoms (PHQ-9 scores 6) as having major depression [OR (95% CI) = 3.13 (0.98-10.00)], similarly likely for moderate-level symptoms (PHQ-9 scores 7-15) [OR (95% CI) = 0.96 (0.56-1.66)], and significantly less likely for high-level symptoms (PHQ-9 scores 16) [OR (95% CI) = 0.50 (0.26-0.97)]. Conclusions: The MINI may identify more depressed cases than the CIDI, and semi- and fully structured interviews may not be interchangeable methods, but these results should be replicated

Femtosecond two-dimensional infrared spectroscopy of synthetic hydrogen-bonded wires: From homogeneous to inhomogeneous dynamics

Femtosecond two-dimensional infrared (2DIR) spectroscopy was carried out on stereo-selectively synthesized poly-alcohols featuring a quasi-linear array of hydrogen-bonds. From the 2DIR spectra pump-frequency-dependent vibrational lifetimes are extracted, which in turn reflect the strength of the coupling between the hydroxyls constituting the H-bonded chain. The line-broadening dynamics reflect uniquely the conformational control of the scaffold supporting the H-bond wire and the resulting structural flexibility of the hydrogen-bond network