Characteristics of DNA-binding proteins determine the biological sensitivity to high-linear energy transfer radiation

Non-homologous end-joining (NHEJ) and homologous recombination repair (HRR), contribute to repair ionizing radiation (IR)-induced DNA double-strand breaks (DSBs). Mre11 binding to DNA is the first step for activating HRR and Ku binding to DNA is the first step for initiating NHEJ. High-linear energy transfer (LET) IR (such as high energy charged particles) killing more cells at the same dose as compared with low-LET IR (such as X or γ rays) is due to inefficient NHEJ. However, these phenomena have not been demonstrated at the animal level and the mechanism by which high-LET IR does not affect the efficiency of HRR remains unclear. In this study, we showed that although wild-type and HRR-deficient mice or DT40 cells are more sensitive to high-LET IR than to low-LET IR, NHEJ deficient mice or DT40 cells are equally sensitive to high- and low-LET IR. We also showed that Mre11 and Ku respond differently to shorter DNA fragments in vitro and to the DNA from high-LET irradiated cells in vivo. These findings provide strong evidence that the different DNA DSB binding properties of Mre11 and Ku determine the different efficiencies of HRR and NHEJ to repair high-LET radiation induced DSBs

Scoring and psychometric validation of the Perception of Anticoagulant Treatment Questionnaire (PACT-Q©)

<p>Abstract</p> <p>Background</p> <p>The 'Perception of Anti-Coagulant Treatment Questionnaire' (PACT-Q) was developed to assess patients' expectations of, and satisfaction with their anticoagulant treatment. This questionnaire needs to be finalised and psychometrically validated.</p> <p>Methods</p> <p>The PACT-Q was included in the United States, the Netherlands and France into three phase III multinational clinical trials conducted to evaluate efficacy and safety of a new long-acting anticoagulant drug (idraparinux) compared to vitamin K antagonist (VKA). PACT-Q was administered to patients with deep venous thrombosis (DVT), atrial fibrillation (AF) or pulmonary embolism (PE) at Day 1, to assess patients' expectations, and at 3 and 6 months to assess patients' satisfaction and treatment convenience and burden. The final structure of the PACT-Q (Principal Component Analysis – PCA – with Varimax Rotation) was first determined and its psychometric properties were then measured with validity of the structure (Multitrait analysis), internal consistency reliability (Cronbach's alpha coefficients) and known-group validity.</p> <p>Results</p> <p>PCA and multitrait analyses showed the multidimensionality of the "Treatment Expectations" dimension, comprising 7 items that had to be scored independently. The "Convenience" and "Burden of Disease and Treatment" dimensions of the hypothesised original structure of the questionnaire were combined, thus resulting in 13 items grouped into the single dimension "Convenience". The "Anticoagulant Treatment Satisfaction" dimension remained unchanged and included 7 items. All items of the "Convenience" and "Anticoagulant Treatment Satisfaction" dimensions displayed good convergent and discriminant validity. The internal consistency reliability was good, with a Cronbach's alpha of 0.84 for the "Convenience" dimension, and 0.76 for the "Anticoagulant Treatment Satisfaction" dimension. Known-group validity was good, especially with regard to occurrence of thromboembolic events within 3 months from randomisation.</p> <p>Conclusion</p> <p>The PACT-Q is a valid and reliable instrument that allows the assessment of patients' expectations and satisfaction regarding anticoagulant treatment, as well as their opinion about treatment convenience of use. Its two-part structure – assessment of expectations at baseline in the first part, and of convenience, burden and treatment satisfaction in the second – was validated and displays good and stable psychometric properties. These results are not sufficient to recommend the use of satisfaction as primary endpoint in clinical trials; further validation work is needed to support the interpretation of PACT-Q dimension scores. However, this first validation makes the PACT-Q an appropriate measure for use in clinical and pharmacoepidemiological research, as well as in real-life studies.</p> <p>Trial Registration</p> <p>(ClinicalTrials.gov numbers, NCT00067093, NCT00062803 and NCT00070655).</p

Measuring impairments of functioning and health in patients with axial spondyloarthritis by using the ASAS Health Index and the Environmental Item Set : translation and cross-cultural adaptation into 15 languages

Introduction: The Assessments of SpondyloArthritis international society Health Index (ASAS HI) measures functioning and health in patients with spondyloarthritis (SpA) across 17 aspects of health and 9 environmental factors (EF). The objective was to translate and adapt the original English version of the ASAS HI, including the EF Item Set, cross-culturally into 15 languages. Methods: Translation and cross-cultural adaptation has been carried out following the forward-backward procedure. In the cognitive debriefing, 10 patients/country across a broad spectrum of sociodemographic background, were included. Results: The ASAS HI and the EF Item Set were translated into Arabic, Chinese, Croatian, Dutch, French, German, Greek, Hungarian, Italian, Korean, Portuguese, Russian, Spanish, Thai and Turkish. Some difficulties were experienced with translation of the contextual factors indicating that these concepts may be more culturally-dependent. A total of 215 patients with axial SpA across 23 countries (62.3% men, mean (SD) age 42.4 (13.9) years) participated in the field test. Cognitive debriefing showed that items of the ASAS HI and EF Item Set are clear, relevant and comprehensive. All versions were accepted with minor modifications with respect to item wording and response option. The wording of three items had to be adapted to improve clarity. As a result of cognitive debriefing, a new response option 'not applicable' was added to two items of the ASAS HI to improve appropriateness. Discussion: This study showed that the items of the ASAS HI including the EFs were readily adaptable throughout all countries, indicating that the concepts covered were comprehensive, clear and meaningful in different cultures

Amino-oxyazijnzuur (AOA) in anjers : ontwikkeling van een HPLC methode

Voor een langer vaasleven worden anjers momenteel na het afsnijden gedurende enige tijd geplaatst in een oplossing van zilverthiosulfaat. Zilverthiosulfaat is uit milieu oogpunt echter minder gewenst. Uit praktijkonderzoek is gebleken dat amino-oxyazijnzuur (AOA) ook het vaasleven verlengt. Voor de acceptatie van het AOA in de anjerteelt is het echter noodzakelijk aan te kunnen tonen of een anjer al dan niet behandeld is met AOA. Doel van het hier beschreven onderzoek was om een methode te ontwikkelen voor het bepalen van AOA in met deze stof behandelde anjers

A Distinct Pool of Nav1.5 Channels at the Lateral Membrane of Murine Ventricular Cardiomyocytes.

Background: In cardiac ventricular muscle cells, the presence of voltage-gated sodium channels Na &lt;sub&gt;v&lt;/sub&gt; 1.5 at the lateral membrane depends in part on the interaction between the dystrophin-syntrophin complex and the Na &lt;sub&gt;v&lt;/sub&gt; 1.5 C-terminal PDZ-domain-binding sequence Ser-Ile-Val (SIV motif). α1-Syntrophin, a PDZ-domain adaptor protein, mediates the interaction between Na &lt;sub&gt;v&lt;/sub&gt; 1.5 and dystrophin at the lateral membrane of cardiac cells. Using the cell-attached patch-clamp approach on cardiomyocytes expressing Na &lt;sub&gt;v&lt;/sub&gt; 1.5 in which the SIV motif is deleted (ΔSIV), sodium current (I &lt;sub&gt;Na&lt;/sub&gt; ) recordings from the lateral membrane revealed a SIV-motif-independent I &lt;sub&gt;Na&lt;/sub&gt; . Since immunostaining has suggested that Na &lt;sub&gt;v&lt;/sub&gt; 1.5 is expressed in transverse (T-) tubules, this remaining I &lt;sub&gt;Na&lt;/sub&gt; might be carried by channels in the T-tubules. Of note, a recent study using heterologous expression systems showed that α1-syntrophin also interacts with the Na &lt;sub&gt;v&lt;/sub&gt; 1.5 N-terminus, which may explain the SIV-motif independent I &lt;sub&gt;Na&lt;/sub&gt; at the lateral membrane of cardiomyocytes. Aim: To address the role of α1-syntrophin in regulating the I &lt;sub&gt;Na&lt;/sub&gt; at the lateral membrane of cardiac cells. Methods and Results: Patch-clamp experiments in cell-attached configuration were performed on the lateral membranes of wild-type, α1-syntrophin knockdown, and ΔSIV ventricular mouse cardiomyocytes. Compared to wild-type, a reduction of the lateral I &lt;sub&gt;Na&lt;/sub&gt; was observed in myocytes from α1-syntrophin knockdown hearts. Similar to ΔSIV myocytes, a remaining I &lt;sub&gt;Na&lt;/sub&gt; was still recorded. In addition, cell-attached I &lt;sub&gt;Na&lt;/sub&gt; recordings from lateral membrane did not differ significantly between non-detubulated and detubulated ΔSIV cardiomyocytes. Lastly, we obtained evidence suggesting that cell-attached patch-clamp experiments on the lateral membrane cannot record currents carried by channels in T-tubules such as calcium channels. Conclusion: Altogether, these results suggest the presence of a sub-pool of sodium channels at the lateral membrane of cardiomyocytes that is independent of α1-syntrophin and the PDZ-binding motif of Na &lt;sub&gt;v&lt;/sub&gt; 1.5, located in membrane domains outside of T-tubules. The question of a T-tubular pool of Na &lt;sub&gt;v&lt;/sub&gt; 1.5 channels, however, remains open