98 research outputs found

    Plausible Extractive Rationalization through Semi-Supervised Entailment Signal

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    The increasing use of complex and opaque black box models requires the adoption of interpretable measures, one such option is extractive rationalizing models, which serve as a more interpretable alternative. These models, also known as Explain-Then-Predict models, employ an explainer model to extract rationales and subsequently condition the predictor with the extracted information. Their primary objective is to provide precise and faithful explanations, represented by the extracted rationales. In this paper, we take a semi-supervised approach to optimize for the plausibility of extracted rationales. We adopt a pre-trained natural language inference (NLI) model and further fine-tune it on a small set of supervised rationales (10%10\%). The NLI predictor is leveraged as a source of supervisory signals to the explainer via entailment alignment. We show that, by enforcing the alignment agreement between the explanation and answer in a question-answering task, the performance can be improved without access to ground truth labels. We evaluate our approach on the ERASER dataset and show that our approach achieves comparable results with supervised extractive models and outperforms unsupervised approaches by >100%> 100\%.Comment: Under revie

    Genetics University of Toronto Thrombophilia Study in Women (GUTTSI): genetic and other risk factors for venous thromboembolism in women

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    BACKGROUND: Women may be at increased risk for venous thromboembolism (VTE) as compared with men. We studied the effects of genetic and biochemical markers of thrombophilia in women, in conjunction with other established risk factors for VTE. METHOD: The present retrospective case-control study was conducted in a thrombosis treatment programme at a large Toronto hospital. The cases were 129 women aged 16-79 years with objectively confirmed VTE. Age-matched control individuals were women who were free of venous thrombosis. Neither cases nor control individuals had known cardiovascular disease. Participants were interviewed regarding personal risk factors for VTE, including smoking, history of malignancy, pregnancy, and oestrogen or oral contraceptive use. Blood specimens were analyzed for common single nucleotide polymorphisms of prothrombin, factor V and methylenetetrahydrofolate reductase (MTHFR; C677T, A1298C and T1317C), and the A66G polymorphism for methionine synthase reductase (MTRR).Fasting plasma homocysteine was also analyzed. RESULTS: Women with VTE were significantly more likely than female control individuals to carry the prothrombin polymorphism and the factor V polymorphism, or to have fasting hyperhomocysteinaemia. Homozygosity for the C677T MTHFR gene was not a significant risk factor for VTE, or were the A1298C or T1317C MTHFR homozygous variants. Also, the A66G MTRR homozygous state did not confer an increased risk for VTE. CONCLUSION: Prothrombin and factor V polymorphisms increased the risk for VTE in women, independent from other established risk factors. Although hyperhomocysteinaemia also heightens this risk, common polymorphisms in two genes that are responsible for homocysteine remethylation do not. These findings are consistent with previous studies that included both men and women

    Guidelines for the labelling of leucocytes with 99mTc-HMPAO

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    We describe here a protocol for labelling autologous white blood cells with 99mTc-HMPAO based on previously published consensus papers and guidelines. This protocol includes quality control and safety procedures and is in accordance with current European Union regulations and International Atomic Energy Agency recommendations

    Rho Kinase Inhibitors Block Melanoma Cell Migration and Inhibit Metastasis

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    There is an urgent need to identify new therapeutic opportunities for metastatic melanoma. Fragment-based screening has led to the discovery of orally available, ATP-competitive AKT kinase inhibitors, AT13148 and CCT129254. These compounds also inhibit the Rho-kinases ROCK 1 and ROCK 2 and we show they potently inhibit ROCK activity in melanoma cells in culture and in vivo. Treatment of melanoma cells with CCT129254 or AT13148 dramatically reduces cell invasion, impairing both “amoeboid-like” and mesenchymal-like modes of invasion in culture. Intravital imaging shows that CCT129254 or AT13148 treatment reduces the motility of melanoma cells in vivo. CCT129254 inhibits melanoma metastasis when administered 2 days after orthotopic intradermal injection of the cells, or when treatment starts after metastases have arisen. Mechanistically, our data suggest that inhibition of ROCK reduces the ability of melanoma cells to efficiently colonize the lungs. These results suggest that these novel inhibitors of ROCK may be beneficial in the treatment of metastasis

    Activated plasma coagulation β-Factor XII-induced vasoconstriction in rats

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    By inducing BK (bradykinin)-stimulated adrenomedullary catecholamine release, bolus injection of the β-fragment of activated plasma coagulation Factor XII (β-FXIIa) transiently elevates BP (blood pressure) and HR (heart rate) of anaesthetized, vagotomized, ganglion-blocked, captopril-treated bioassay rats. We hypothesized that intravenous infusion of β-FXIIa into intact untreated rats would elicit a qualitatively similar vasoconstrictor response. BN (Brown Norway) rats received for 60 min either: (i) saline (control; n=10); (ii) β-FXIIa (85 ng/min per kg of body weight; n=9); or (iii) β-FXIIa after 2ADX (bilateral adrenalectomy; n=9). LV (left ventricular) volume and aortic BP were recorded before (30 min baseline), during (60 min) and after (30 min recovery) the infusion. TPR (total peripheral resistance) was derived from MAP (mean arterial pressure), SV (stroke volume) and HR. Saline had no haemodynamic effects. β-FXIIa infusion increased its plasma concentration 3-fold in both groups. In adrenally intact rats, β-FXIIa infusion increased MAP by 6% (5±2 mmHg) and TPR by 45% (0.50±0.12 mmHg/ml per min), despite falls in SV (−38±8 μl) and HR [−18±5 b.p.m. (beats/min)] (all P<0.05). In 2ADX rats, β-FXIIa had no HR effect, but decreased SV (−89±9 μl) and MAP (−4±1 mmHg), and increased TPR by 66% (0.59±0.15 mmHg/ml per min) (all P<0.05). After infusion, adrenally intact rats exhibited persistent vasoconstriction (MAP, 10±1 mmHg; TPR, 0.55±0.07 mmHg/ml per min; both P<0.05), whereas in 2ADX rats, MAP remained 5±1 mmHg below baseline (P<0.05) and TPR returned to baseline. End-study arterial adrenaline (epinephrine) concentrations in the three groups were 1.9±0.6, 9.8±4.1 and 0.6±0.2 nmol/l respectively. Thus, in neurally intact lightly anaesthetized untreated rats, β-FXIIa infusion induces both adrenal catecholamine-mediated and adrenally independent increases in peripheral resistance

    Artemisinin-resistant K13 mutations rewire Plasmodium falciparum's intra-erythrocytic metabolic program to enhance survival

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    The emergence and spread of artemisinin resistance, driven by mutations in Plasmodium falciparum K13, has compromised antimalarial efficacy and threatens the global malaria elimination campaign. By applying systems-based quantitative transcriptomics, proteomics, and metabolomics to a panel of isogenic K13 mutant or wild-type P. falciparum lines, we provide evidence that K13 mutations alter multiple aspects of the parasite's intra-erythrocytic developmental program. These changes impact cell-cycle periodicity, the unfolded protein response, protein degradation, vesicular trafficking, and mitochondrial metabolism. K13-mediated artemisinin resistance in the Cambodian Cam3.II line was reversed by atovaquone, a mitochondrial electron transport chain inhibitor. These results suggest that mitochondrial processes including damage sensing and anti-oxidant properties might augment the ability of mutant K13 to protect P. falciparum against artemisinin action by helping these parasites undergo temporary quiescence and accelerated growth recovery post drug elimination

    Asian Pacific Society of Cardiology Consensus Recommendations for Pre-participation Screening in Young Competitive Athletes

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    Sports-related sudden cardiac death is a rare but devastating consequence of sports participation. Certain pathologies underlying sports-related sudden cardiac death could have been picked up pre-participation and the affected athletes advised on appropriate preventive measures and/or suitability for training or competition. However, mass screening efforts – especially in healthy young populations – are fraught with challenges, most notably the need to balance scarce medical resources and sustainability of such screening programmes, in healthcare systems that are already stretched. Given the rising trend of young sports participants across the Asia-Pacific region, the working group of the Asian Pacific Society of Cardiology (APSC) developed a sports classification system that incorporates dynamic and static components of various sports, with deliberate integration of sports events unique to the Asia-Pacific region. The APSC expert panel reviewed and appraised using the Grading of Recommendations Assessment, Development, and Evaluation system. Consensus recommendations were developed, which were then put to an online vote. Consensus was reached when 80% of votes for a recommendation were agree or neutral. The resulting statements described here provide guidance on the need for cardiovascular pre-participation screening for young competitive athletes based on the intensity of sports they engage in

    The COVID-19 pandemic: a letter to G20 leaders

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