290 research outputs found

    Dilatometric investigation of deformation mechanisms in polystyrene-polyethylene block copolymer blends. Correlation between Poisson ratio and adhesion

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    The deformation behavior of blends contg. polystyrene (I) [9003-53-6], low-d. polyethylene (II) [9002-88-4], and a hydrogenated butadiene-styrene diblock copolymer (III) was examd. by tensile testing with simultaneous vol. measurements. Assuming that shearing causes no vol. changes, crazing, after yielding, was the only deformation mechanism in blends with low I and III contents. Shearing became important in blends with high I concns. due to formation of a semicontinuous low modulus phase. The decrease in the Poisson ratio with increasing II content in I-II blends, as opposed to an increase in the presence of III, shows the Poisson ratio to be very sensitive to adhesion between the components. The toughness of I-II blends is discussed in terms of concns. of craze nuclei. Too few craze nuclei give rise to brittle failure because the resulting low no. of crazes cannot accommodate much deformation of the matrix whereas too many craze nuclei also cause brittle failure because of the high probability of combination of the crazes to form a crack. The concn. of craze nuclei depends on the no. of dispersed particles and their adhesion to the matrix. [on SciFinder (R)

    Dilatometer for use in tensile tests

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    Inhibition of sarcolemmal FAT/CD36 by sulfo-N-succinimidyl oleate rapidly corrects metabolism and restores function in the diabetic heart following hypoxia/reoxygenation.

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    AIMS: The type 2 diabetic heart oxidizes more fat and less glucose, which can impair metabolic flexibility and function. Increased sarcolemmal fatty acid translocase (FAT/CD36) imports more fatty acid into the diabetic myocardium, feeding increased fatty acid oxidation and elevated lipid deposition. Unlike other metabolic modulators that target mitochondrial fatty acid oxidation, we proposed that pharmacologically inhibiting fatty acid uptake, as the primary step in the pathway, would provide an alternative mechanism to rebalance metabolism and prevent lipid accumulation following hypoxic stress. METHODS AND RESULTS: Hearts from type 2 diabetic and control male Wistar rats were perfused in normoxia, hypoxia and reoxygenation, with the FAT/CD36 inhibitor sulfo-N-succinimidyl oleate (SSO) infused 4 min before hypoxia. SSO infusion into diabetic hearts decreased the fatty acid oxidation rate by 29% and myocardial triglyceride concentration by 48% compared with untreated diabetic hearts, restoring fatty acid metabolism to control levels following hypoxia-reoxygenation. SSO infusion increased the glycolytic rate by 46% in diabetic hearts during hypoxia, increased pyruvate dehydrogenase activity by 53% and decreased lactate efflux rate by 56% compared with untreated diabetic hearts during reoxygenation. In addition, SSO treatment of diabetic hearts increased intermediates within the second span of the Krebs cycle, namely fumarate, oxaloacetate, and the FAD total pool. The cardiac dysfunction in diabetic hearts following decreased oxygen availability was prevented by SSO-infusion prior to the hypoxic stress. Infusing SSO into diabetic hearts increased rate pressure product by 60% during hypoxia and by 32% following reoxygenation, restoring function to control levels. CONCLUSIONS: Diabetic hearts have limited metabolic flexibility and cardiac dysfunction when stressed, which can be rapidly rectified by reducing fatty acid uptake with the FAT/CD36 inhibitor, SSO. This novel therapeutic approach not only reduces fat oxidation but also lipotoxicity, by targeting the primary step in the fatty acid metabolism pathway

    Characterization of ERG, AR and PTEN gene status in circulating tumor cells from patients with castration-resistant prostate cancer

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    Hormone-driven expression of the ERG oncogene after fusion with TMPRSS2 occurs in 30% to 70% of therapy-naive prostate cancers. Its relevance in castration-resistant prostate cancer (CRPC) remains controversial as ERG is not expressed in some TMPRSS2-ERG androgen-independent xenograft models. However, unlike these models, CRPC patients have an increasing prostate-specific antigen, indicating active androgen receptor signaling. Here, we collected blood every month from 89 patients (54 chemotherapy-naive patients and 35 docetaxel-treated patients) treated in phase I/phase II clinical trials of an orally available, highly specific CYP17 inhibitor, abiraterone acetate, that ablates the synthesis of androgens and estrogens that drive TMPRSS2-ERG fusions. We isolated circulating tumor cells (CTC) by anti-epithelial cell adhesion molecule immunomagnetic selection followed by cytokeratin and CD45 immunofluorescence and 4',6diamidino-2-phenylindole staining. We used multicolor fluorescence in situ hybridization to show that CRPC CTCs, metastases, and prostate tissue invariably had the same ERG gene status as therapy-naive tumors (n = 31). We then used quantitative reverse transcription-PCR to show that ERG expression was maintained in CRPC. We also observed homogeneity in ERG gene rearrangement status in CTCs (n = 48) in contrast to significant heterogeneity of AR copy number gain and PTEN loss, suggesting that rearrangement of ERG may be an earlier event in prostate carcinogenesis. We finally report a significant association between ERG rearrangements in therapy-naive tumors, CRPCs, and CTCs and magnitude of prostate-specific antigen decline (P = 0.007) in CRPC patients treated with abiraterone acetate. These data confirm that CTCs are malignant in origin and indicate that hormone-regulated expressio

    Trial by Dutch laboratories for evaluation of non-invasive prenatal testing. Part I—clinical impact

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    Objective: To evaluate the clinical impact of nationwide implementation of genome-wide non-invasive prenatal testing (NIPT) in pregnancies at increased risk for fetal trisomies 21, 18 and 13 (TRIDENT study). Method: Women with elevated risk based on first trimester combined testing (FCT ≥ 1:200) or medical history, not advanced maternal age alone, were offered NIPT as contingent screening test, performed by Dutch University Medical laboratories. We analyzed uptake, test performance, redraw/failure rate, turn-around time and pregnancy outcome. Results: Between 1 April and 1 September 2014, 1413/23 232 (6%) women received a high-risk FCT result. Of these, 1211 (85.7%) chose NIPT. One hundred seventy-nine women had NIPT based on medical history. In total, 1386/1390 (99.7%) women received a result, 6 (0.4%) after redraw. Mean turn-around time was 14 days. Follow-up was available in 1376 (99.0%) pregnancies. NIPT correctly predicted 37/38 (97.4%) trisomies 21, 18 or 13 (29/30, 4/4 and 4/4 respectively); 5/1376 (0.4%) cases proved to be false positives: trisomies 21 (n = 2), 18 (n = 1) and 13 (n = 2). Estimated reduction in invasive testing was 62%. Conclusion: Introduction of NIPT in the Dutch National healthcare-funded Prenatal Screening Program resulted in high uptake and a vast reduction of invasive testing. Our study supports offering NIPT to pregnant women at increased risk for fetal trisomy. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd

    Cancer-ID:Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood

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    Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1μm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic

    Craniectomy for Malignant Cerebral Infarction: Prevalence and Outcomes in US Hospitals

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    Randomized trials have demonstrated the efficacy of craniectomy for the treatment of malignant cerebral edema following ischemic stroke. We sought to determine the prevalence and outcomes related to this by using a national database.Patient discharges with ischemic stroke as the primary diagnosis undergoing craniectomy were queried from the US Nationwide Inpatient Sample from 1999 to 2008. A subpopulation of patients was identified that underwent thrombolysis. Two primary end points were examined: in-hospital mortality and discharge to home/routine care. To facilitate interpretations, adjusted prevalence was calculated from the overall prevalence and two age-specific logistic regression models. The predictive margin was then generated using a multivariate logistic regression model to estimate the probability of in-hospital mortality after adjustment for admission type, admission source, length of stay, total hospital charges, chronic comorbidities, and medical complications.After excluding 71,996 patients with the diagnosis of intracranial hemorrhage and posterior intracranial circulation occlusion, we identified 4,248,955 adult hospitalizations with ischemic stroke as a primary diagnosis. The estimated rates of hospitalizations in craniectomy per 10,000 hospitalizations with ischemic stroke increased from 3.9 in 1999-2000 to 14.46 in 2007-2008 (p for linear trend<0.001). Patients 60+ years of age had in-hospital mortality of 44% while the 18-59 year old group was found to be 24% (p = 0.14). Outcomes were comparable if recombinant tissue plasminogen activator had been administered.Craniectomy is being increasingly performed for malignant cerebral edema following large territory cerebral ischemia. We suspect that the increase in the annual incidence of DC for malignant cerebral edema is directly related to the expanding collection of evidence in randomized trials that the operation is efficacious when performed in the correct patient population. In hospital mortality is high for all patients undergoing this procedure
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