630 research outputs found

    Expression, purification and preliminary crystal analysis of the human low Mr phosphotyrosine protein phosphatase isoform 1

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    AbstractThe genes of the human low Mr phosphotyrosine protein phosphatase (PTPase) isoforms 1 (IF1) and 2 (IF2) were isolated by screening a human placenta cDNA library, cloned in pGEX and expressed in E. coli as fusion proteins with glutathione S-transferase. The recombinant proteins were purified by a rapid one-step procedure allowing each enzyme to purify with high final yield and specific activity. This result is important for IF1, whose purification from natural sources is difficult, due to precipitation propensity, thus hindering structural studies. The enzymes obtained showed kinetic parameters very similar to those previously determined for the enzymes purified by classical procedures from both human erythrocytes and rat liver. These recombinant enzymes can therefore be used in place of those purified from natural sources for every purpose. IF1 and IF2 crystals were also grown. IF1 crystals were X-ray-grade, diffracted to better than 2.4 Ã… and were suitable for high resolution X-ray structure determination

    Mitogen-Activated Protein Kinase Phosphatase-1 Is Overexpressed in Non-Small Cell Lung Cancer and Is an Independent Predictor of Outcome in Patients

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    An increase in the activity of the mitogen-activated protein kinases (MAPKs) has been correlated with a more malignant phenotype in several tumor models in vitro and in vivo. A key regulatory mechanism of the MAPKs [extracellular signal-regulated kinase (ERK); c-jun NH(2)-terminal kinase (JNK); and p38] is the dual specificity phosphatase CL100, also called MAPK phosphatase-1 (MKP-1). This study was designed to examine the involvement of CL100/MKP-1 and stress-related MAPKs in lung cancer. EXPERIMENTAL DESIGN: We assessed the expression of CL100/MKP-1 and the activation of the MAPKs in a panel of 18 human cell lines [1 primary normal bronchial epithelium, 8 non-small cell lung cancer (NSCLC), 7 small cell lung cancer (SCLC), and 2 carcinoids] and in 108 NSCLC surgical specimens. RESULTS: In the cell lines, CL100/MKP-1 expression was substantially higher in NSCLC than in SCLC. P-ERK, P-JNK, and P-p38 were activated in SCLC and NSCLC, but the degree of their activation was variable. Immunohistochemistry in NSCLC resection specimens showed high levels of CL100/MKP-1 and activation of the three MAPK compared with normal lung. In univariate analysis, no relationship was found among CL100/MKP-1 expression and P-ERK, P-JNK, or P-p38. Interestingly, high CL100/MKP-1 expression levels independently predicted improved survival in multivariate analysis. JNK activation associated with T(1-2) and early stage, whereas ERK activation correlated with late stages and higher T and N. Neither JNK nor ERK activation were independent prognostic factors when studied for patient survival. CONCLUSIONS: Our data indicate the relevance of MAPKs and CL100/MKP-1 in lung cancer and point at CL100/MKP-1 as a potential positive prognostic factor in NSCLC. Finally, our study supports the search of new molecular targets for lung cancer therapy within the MAPK signaling pathway

    Diagnostic procedures for non-small-cell lung cancer (NSCLC): recommendations of the European Expert Group

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    Background There is currently no Europe-wide consensus on the appropriate preanalytical measures and workflow to optimise procedures for tissue-based molecular testing of non-small-cell lung cancer (NSCLC). To address this, a group of lung cancer experts (see list of authors) convened to discuss and propose standard operating procedures (SOPs) for NSCLC. Methods Based on earlier meetings and scientific expertise on lung cancer, a multidisciplinary group meeting was aligned. The aim was to include all relevant aspects concerning NSCLC diagnosis. After careful consideration, the following topics were selected and each was reviewed by the experts: surgical resection and sampling; biopsy procedures for analysis; preanalytical and other variables affecting quality of tissue; tissue conservation; testing procedures for epidermal growth factor receptor, anaplastic lymphoma kinase and ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) in lung tissue and cytological specimens; as well as standardised reporting and quality control (QC). Finally, an optimal workflow was described. Results Suggested optimal procedures and workflows are discussed in detail. The broad consensus was that the complex workflow presented can only be executed effectively by an interdisciplinary approach using a well-trained team. Conclusions To optimise diagnosis and treatment of patients with NSCLC, it is essential to establish SOPs that are adaptable to the local situation. In addition, a continuous QC system and a local multidisciplinary tumour-type-oriented board are essential

    Patients with Cluster A Personality Disorders in Psychotherapy: An Effectiveness Study

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    Abstract BACKGROUND: While psychopharmacological studies are common in patients with cluster A personality disorders, the effects of psychotherapy have received little attention. The aim of this study is to explore whether psychotherapeutic treatment yields health gains for these patients. METHODS: The study was conducted between March 2003 and June 2008 in 6 mental health care centres in the Netherlands, with a sample of 57 patients with a DSM-IV-TR axis II cluster A diagnosis. Patients were assigned to 3 settings of psychotherapeutic treatment (outpatient, day hospital, inpatient), and effectiveness was assessed at 18 months after baseline. An intention-to-treat analysis was conducted for psychiatric symptoms (Brief Symptom Inventory), psychosocial functioning (Outcome Questionnaire-45) and quality of life (EQ-5D), using multilevel statistical modelling. As the study was non-randomised, the propensity score method was used to control for initial differences. RESULTS: Patients in the day hospital and inpatient group improved substantially in terms of psychiatric symptoms, social and interpersonal functioning, and quality of life. Patients in the outpatient group showed less improvement. Direct comparison of the improvement of psychiatric symptoms showed significant results in favour of day hospital (p = 0.046) and inpatient (p = 0.01) treatment, as compared to outpatient treatment. However, due to substantial baseline differences, this direct comparison should be judged carefully. CONCLUSIONS: Cluster A psychopathology is not a contraindication to benefit from psychotherapy. This is especially true for more intensive forms like inpatient and day hospital treatment. Future research should focus more on psychotherapeutic treatment to gain further insight into effective treatment options for this patient grou

    Substrate-Assisted Catalysis Unifies Two Families of Chitinolytic Enzymes

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    Hen egg-white lysozyme has long been the paradigm for enzymatic glycosyl hydrolysis with retention of configuration, with a protonated carboxylic acid and a deprotonated carboxylate participating in general acid-base catalysis. In marked contrast, the retaining chitin degrading enzymes from glycosyl hydrolase families 18 and 20 all have a single glutamic acid as the catalytic acid but lack a nucleophile on the enzyme. Both families have a catalytic (βα)8-barrel domain in common. X-ray structures of three different chitinolytic enzymes complexed with substrates or inhibitors identify a retaining mechanism involving a protein acid and the carbonyl oxygen atom of the substrate’s C2 N-acetyl group as the nucleophile. These studies unambiguously demonstrate the distortion of the sugar ring toward a sofa conformation, long postulated as being close to that of the transition state in glycosyl hydrolysis.
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