181,272 research outputs found
Effect of Oocyte Vitrification Before and After in Vitro Maturation Towards Bcl-2, Bax and Bcl-2/Bax Ratio Expression
Objectives: to compare the expression of Bcl-2, Bax and Bcl-2/Bax ratio in cumulus cell and oocyte between vitrified oocyte pre and post in vitro maturation.Materials and Methods: Maturation was operated in medium TC 100 µl for 24 hours. Vitrification begins with washing oocyte in PBS basic medium supplemented of 20% serum for 1-2 minutes, followed by equilibration medium PBS + 20% serum + 10% ethylene glycol for 10-14 minutes, then transferred to 20% serum + PBS + 0.5 M sucrose + 15% ethylene glycol + PROH 15% for 25-30 seconds. Thawing is processed by submerging the oocytes in the media: 1). PBS + 20% serum + 0.5 M sucrose, 2). PBS + 20% serum + 0.25 M sucrose, and 3). PBS + 20% serum + 0.1 M sucrose. Imunocytochemistry observed the expression of Bcl-2, bax and Bcl-2/bax ratio.Results: Bcl-2 expression on oocyte in control group differed significantly with treatment group, Bcl-2 expression on cumulus in control group differed significantly with treatment 1 group. Bax expression on oocyte in control group differed significantly with treatment group. Bax expression on cumulus in control group differed significantly with treatment group. Bcl-2/Bax expression ratio on oocyte and cumulus did not differ significantly in all groupConclusion: No difference Bcl-2/Bax expression ratio on oocyte and cumulus between vitrified oocyte pre and post in vitro maturation
Distinct promoter elements mediate the co-operative effect of Brn-3a and p53 on the p21 promoter and their antagonism on the Bax promoter
Although the promoters of both the Bax and p21 genes are activated by p53, they differ in the effect on this activation of the POU family transcription factor Brn-3a. Thus, Brn-3a inhibits activation of the Bax promoter by p53 but enhances the ability of p53 to activate the p21 promoter. We demonstrate that repression of p53-mediated activation of the Bax promoter involves a complex upstream sequence in which two Brn-3a response elements flank the p53 response element. In contrast, a minimal p21 promoter is activated by Brn-3a and such activation cannot be abolished without abolishing basal promoter activity. Moreover, synergistic activation by Brn-3a and p53 continues to be observed when the p53-binding sites in the p21 promoter are substituted by the Bax p53 site or by the region of the Bax promoter essential for Brn-3a-mediated repression, indicating that the p21 core promoter plays a central role in this response. The significance of these effects is discussed in terms of the different responses of the Bax and p21 promoters and the overlapping but distinct roles of Brn-3a and p53 in neuronal growth arrest and apoptosis
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Readers’ cognitive processes during IELTS reading tests: evidence from eye tracking
The research described in this report investigates readers' mental processes as they complete onscreen IELTS (International English Language Testing System) reading test items. It employs up-to-date eye tracking technology to research readers' eye movements and aims, among other things, to contribute to an understanding of the cognitive validity of reading test items (Glaser. 1991; Field forthcoming).
Participants were a group of Malaysian undergraduates (n=71) taking an onscreen test consisting of two IELTS reading passages with a total of 11 test items. The eye movements of a random sample of these participants (n=38) were tracked. Questionnaire and stimulated recall interview data were also collected, and were important in order to interpret and explain the eye tracking data.
Findings demonstrated significant differences between successful and unsuccessful test-takers on a number of dimensions, including their ability to read expeditiously (Khalifa and Weir. 2009). and their focus on particular aspects of the test items and the reading texts. This demonstrates the potential of eye tracking, in combination with post- hoc interview and questionnaire data, to offer new insights into the cognitive processes of successful and unsuccessful candidates in a reading test. It also gives unprecedented insights into the cognitive processing of successful and unsuccessful readers doing language tests.
As a consequence, the findings should be of value to teachers and learners, and also to examination boards seeking to validate and prepare reading tests, as well as psycholinguists and others interested in the cognitive processes of readers
Improved Error Bounds Based on Worst Likely Assignments
Error bounds based on worst likely assignments use permutation tests to
validate classifiers. Worst likely assignments can produce effective bounds
even for data sets with 100 or fewer training examples. This paper introduces a
statistic for use in the permutation tests of worst likely assignments that
improves error bounds, especially for accurate classifiers, which are typically
the classifiers of interest.Comment: IJCNN 201
Validation of Voting Committees
This article contains a method to bound the test errors of voting committees with members chosen from a pool of trained classifiers. There are so many prospective committees that validating them directly does not achieve useful error bounds. Because there are fewer classifiers than prospective committees, it is better to validate the classifiers individually than use linear programming to infer committee error bounds. We test the method using credit card data. Also, we extend the method to infer bounds for classifiers in general
Erythrocytes as Carriers of Therapeutic Enzymes.
Therapeutic enzymes are administered for the treatment of a wide variety of diseases. They exert their effects through binding with a high affinity and specificity to disease-causing substrates to catalyze their conversion to a non-noxious product, to induce an advantageous physiological change. However, the metabolic and clinical efficacies of parenterally or intramuscularly administered therapeutic enzymes are very often limited by short circulatory half-lives and hypersensitive and immunogenic reactions. Over the past five decades, the erythrocyte carrier has been extensively studied as a strategy for overcoming these limitations and increasing therapeutic efficacy. This review examines the rationale for the different therapeutic strategies that have been applied to erythrocyte-mediated enzyme therapy. These strategies include their application as circulating bioreactors, targeting the monocyte-macrophage system, the coupling of enzymes to the surface of the erythrocyte and the engineering of CD34+ hematopoietic precursor cells for the expression of therapeutic enzymes. An overview of the diverse biomedical applications for which they have been investigated is also provided, including the detoxification of exogenous chemicals, thrombolytic therapy, enzyme replacement therapy for metabolic diseases and antitumor therapy
Cleavage in Dutch society : changing patterns of social and economic discrimination
The paper considers a (static) portfolio system that satisfies adding-up contraints and the gross substitution theorem. The paper shows the relationship of the two conditions to the weak dominant diagonal property of the matrix of interest rate elasticities. This enables to investigate the impact of simultaneous changes in interest rates on the asset demands.
Accumulation of tissue factor in endothelial cells induces cell apoptosis, mediated through p38 and p53 activation
We previously reported that high levels of tissue factor (TF) can induce cellular apoptosis in endothelial. In this study, TF-mediated mechanisms of induction of apoptosis were explored. Endothelial cells were transfected to express wild-type TF. Additionally, cells were transfected to express Asp253-substituted, or Ala253-substitued TF to enhance or prevent TF release respectively. Alternatively, cells were pre-incubated with TF-rich and TF-poor microvesicles. Cell proliferation, apoptosis and the expression of cyclin D1, p53, bax and p21 were measured following activation of cells with PAR2-agonist peptide. Greatest levels of cell proliferation and cyclin D1 expression were observed in cells expressing wild-type or Asp253-substituted TF. In contrast, increased cellular apoptosis was observed in cells expressing Ala253-substituted TF, or cells pre-incubated with TF-rich microvesicles. The level of p53 protein, p53-phosphorylation at ser33, p53 nuclear localisation and transcriptional activity, but not p53 mRNA, were increased in cells expressing wild-type and Ala253-substituted TF, or in cells pre-incubated with TF-rich microvesicles. However, the expression of bax and p21 mRNA, and Bax protein were only increased in cells pre-incubated with TF-rich microvesicle and in cells expressing Ala253-substituted TF. Inhibition of the transcriptional activity of p53 using pifithrin-α suppressed the expression of Bax. Finally, siRNA–mediated suppression of p38α, or inhibition using SB202190 significantly reduced the p53 protein levels, p53 nuclear localisation and transcriptional activity, suppressed Bax expression and prevented cellular apoptosis. In conclusion, accumulation of TF within endothelial cell, or sequestered from the surrounding can induce cellular apoptosis through mechanisms mediated by p38, and involves the stabilisation of p53
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