861 research outputs found

    Prince Edward Island Heritage Foundation

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    Brief of Law Professors as Amicus Curiae in Support of Respondent

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    Inventors lacking assurance of a market, or even the right to practice patented inventions, face considerable risk. Those who qualify for patents, in return for disclosure, receive only the assistance of the courts in excluding others from economic exploitation of their inventions. Already subject to many legislative and judicial limitations, patents should not be further subject to the functional equivalent of private inverse condemnation without congressional action

    A BAYESIAN APPROACH TO DOSE-RESPONSE ASSESSMENT AND DRUG-DRUG INTERACTION ANALYSIS: APPLICATION TO IN VITRO STUDIES

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    The considerable search for synergistic agents in cancer research is motivated by the therapeutic benefits achieved by combining anti-cancer agents. Synergistic agents make it possible to reduce dosage while maintaining or enhancing a desired effect. Other favorable outcomes of synergistic agents include reduction in toxicity and minimizing or delaying drug resistance. Dose-response assessment and drug-drug interaction analysis play an important part in the drug discovery process, however analysis are often poorly done. This dissertation is an effort to notably improve dose-response assessment and drug-drug interaction analysis. The most commonly used method in published analysis is the Median-Effect Principle/Combination Index method (Chou and Talalay, 1984). The Median-Effect Principle/Combination Index method leads to inefficiency by ignoring important sources of variation inherent in dose-response data and discarding data points that do not fit the Median-Effect Principle. Previous work has shown that the conventional method yields a high rate of false positives (Boik, Boik, Newman, 2008; Hennessey, Rosner, Bast, Chen, 2010) and, in some cases, low power to detect synergy. There is a great need for improving the current methodology. We developed a Bayesian framework for dose-response modeling and drug-drug interaction analysis. First, we developed a hierarchical meta-regression dose-response model that accounts for various sources of variation and uncertainty and allows one to incorporate knowledge from prior studies into the current analysis, thus offering a more efficient and reliable inference. Second, in the case that parametric dose-response models do not fit the data, we developed a practical and flexible nonparametric regression method for meta-analysis of independently repeated dose-response experiments. Third, and lastly, we developed a method, based on Loewe additivity that allows one to quantitatively assess interaction between two agents combined at a fixed dose ratio. The proposed method makes a comprehensive and honest account of uncertainty within drug interaction assessment. Extensive simulation studies show that the novel methodology improves the screening process of effective/synergistic agents and reduces the incidence of type I error. We consider an ovarian cancer cell line study that investigates the combined effect of DNA methylation inhibitors and histone deacetylation inhibitors in human ovarian cancer cell lines. The hypothesis is that the combination of DNA methylation inhibitors and histone deacetylation inhibitors will enhance antiproliferative activity in human ovarian cancer cell lines compared to treatment with each inhibitor alone. By applying the proposed Bayesian methodology, in vitro synergy was declared for DNA methylation inhibitor, 5-AZA-2\u27-deoxycytidine combined with one histone deacetylation inhibitor, suberoylanilide hydroxamic acid or trichostatin A in the cell lines HEY and SKOV3. This suggests potential new epigenetic therapies in cell growth inhibition of ovarian cancer cells

    Adverse infusion reactions to rituximab in systemic lupus erythematosus: a retrospective analysis

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    Background To undertake a retrospective review of patients with SLE who had received Rituximab in order to determine the rates and associated patient characteristics of clinically significant adverse infusion reactions. Methods A descriptive analysis was undertaken of each infusion reaction, which was then assessed using the clinical information available to hypothesise on the possible underlying mechanism(s). Results Records of 136 SLE patients previously treated with 481 individual infusions of Rituximab were reviewed. A total of 22 patients (17.6%) had 28 (5.8% of total infusions) documented clinically significant adverse infusion reactions. Average age at first Rituximab infusion in patients without a reaction was 37 years (range 16–73) compared with 30 years (range 18–56) in those with a reaction. A high proportion of men (18.2%) experienced an infusion reaction. Severity and type of reaction varied. 6.4% of those who had a reaction were not retreated. Conclusions While Rituximab remains an important tool in the treatment of SLE it is important to be aware that rates of infusion reactions may be more significant in SLE than in other diseases. A prospective study is required to better characterise the reactions

    ATP Reception and Chemosensory Adaptation in \u3c/i\u3eTetrahymena thermophila\u3c/i\u3e

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    Micromolar concentrations of adenosine triphosphate (ATP) and its non-hydrolyzable analog β- γ -methylene ATP are both effective depolarizing chemorepellents in Tetrahymena thermophila. Chemorepellent behavior consists of repeated bouts of backward swimming (avoidance reactions) that can easily be quantified to provide a convenient bioassay for purinergic reception studies. Chemosensory adaptation occurs following prolonged exposure (10 min) to the repellents, and cells regain normal swimming behavior. Adaptation is specific since cells that are behaviorally adapted to either ATP or β- γ -methylene ATP still retain full responsiveness to the chemorepellents GTP and lysozyme. However, cross adaptation occurs between ATP and β- γ -methylene ATP, suggesting that they involve the same receptor. Behavioral sensitivity to both ATP and β- γ -methylene ATP is increased by the addition of Na+, but addition of either Ca2+ or Mg2+ dramatically decreases the response to ATP. These ionic effects are correlated with in vivo ATP hydrolysis, suggesting that divalent ions decrease purinergic sensitivity by activating a Ca2+- or Mg2+-dependent ecto-ATPase to hydrolyze the ATP signal. In vivo [32P]ATP binding studies and Scatchard analysis suggest that the behavioral adaptation is due to a decrease in the number of surface binding sites, as represented by decreased Bmax values. All these changes are reversible (de-adaptation) after 12 min in a repellent-free buffer. Electrophysiological analysis showed that both β- γ -methylene ATP (10 micromol l-1) and ATP (500 micromol l-1) elicited sustained, reversible depolarizations while GTP (10 micromol l-1) produced a transient depolarization, suggesting that the chemosensory response pathways for ATP and GTP reception may differ. There may be separate ATP and GTP receptors since ATP and GTP responses do not cross-adapt and ‘cold’ (unlabeled) GTP is not a good inhibitor of [32P]ATP binding. These results suggests that T. thermophila possess high-affinity surface receptors for ATP that are down-regulated during chemosensory adaptation. These ATP receptors may act as chemorepellent receptors to enable T. thermophila to recognize recently lysed cells and avoid a possibly deleterious situation. This is the simplest eukaryotic organism to show an electrophysiological response to external ATP

    Identification of the major cytoplasmic regions of the Neurospora crassa plasma membrane H (+)-ATPase using protein chemical techniques.

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    The transmembrane topography of the Neurospora crassa plasma membrane H(+)-ATPase has been investigated using purified, reconstituted components and direct protein chemical techniques. Reconstituted proteoliposomes containing H(+)-ATPase molecules oriented predominantly with their cytoplasmic surface facing outward were treated with trypsin to liberate peptides present on the cytoplasmic surface of the H(+)-ATPase as recently described (Hennessey, J.P., Jr., and Scarborough, G. (1990) J. Biol. Chem. 265, 532-537. The released peptides were then separated from the proteoliposomes by gel filtration chromatography and further purified by high performance liquid chromatography. Fourteen such peptides were identified by NH2-terminal amino acid sequence analysis, directly defining these parts of the molecule as present on the cytoplasmic surface of the membrane. Moreover, this information identified several additional flanking stretches as likely to be cytoplasmically located by virtue of the fact that they are too short to cross the membrane and return. These results and the results of other recent experiments establish 417 residues of the 919 present in the ATPase molecule, at positions 2-100, 186-256, 441-663, and 897-920, as cytoplasmically located. Taken together with the results of our preliminary investigations of the membrane embedded sectors of the ATPase, this information allows the formulation of a reasonably detailed model for the transmembrane topography of the ATPase polypeptide chain

    Does ethnicity and culture affect the non- compliancy of cervical cancer screening?

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    Background: Globally, an estimated 528,000 women develop cervical cancer (CC) each year, 266,000 of whom die from the disease. CC is the fourth most-common cancer in women worldwide and fourteenth in the UK, where 3,200 cases are diagnosed each year. In England CC is more common among White females and more common among women in deprived areas. In 1989, the NHS Cervical ScreeningProgramme (NHSCSP) developed a screening programme aimed at identifying women who may be at risk of developing CC. However, incidence rates for CC are projected to rise by 43% in the UK between 2014 and 2035, to 17 cases per 100,000 females by2035, which suggests that there are ongoing barriers that may be preventing women from attending cervical cancer screening (CCS). The primary goal of this extended literature review, it to examine these barriers, with particular emphasis on the extent to which they are shaped by ethnicity.Methodology: The research question and selection of relevant keywords were formulated using the PICO(S) framework. Six databases were used to search for relevant literature. Cumulative Index of Nursing and Allied Health Literature (CINAHL), Medline and SCOPUS provided literature specific to the nursing and allied health perspectives while PsycINFO and Applied Social Sciences Index andAbstract (ASSIA) were used to find studies focused on sociological and psychological aspects of the research question. The use of the Cochrane database provided previous research papers relevant to the topic. All papers were screened for eligibility against the inclusion and exclusion criteria and critically appraised, and quality assessed using the Joanna Briggs Institute (JBI) checklist for systematic reviews, with reference to the Boland, Cherry & Dickson3 theories of methodology.Results: Thematic analysis of the eight studies was carried out in line with the process outlined by Braun & Clark4 to identify recurring themes and barriers to CCS access: (1) Psychological and emotional barriers (2) Financial barriers (3) Perceptions and previous experiences.Discussion: The barriers are applicable to women from all ethnicities, to varying degrees. However, females from marginalized, educationally deprived or underserved groups are less likely to attend CCS screening due to the barriers identified. This has immense implications for CC policy and practice

    Identification of the membrane-embedded regions of the Neurospora crassa plasma membrane H (+)-ATPase.

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    Reconstituted proteoliposomes containing functional Neurospora crassa plasma membrane H(+)-ATPase molecules oriented predominantly with their cytoplasmic surface exposed were treated with trypsin and then subjected to Sepharose CL-6B column chromatography to remove the liberated peptides. The peptides remaining associated with the liposomes were then separated from the phospholipid by Sephadex LH-60 column chromatography and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Six H(+)-ATPase peptides with approximate molecular masses of 7, 7.5, 8, 10, 14, and 21 kDa were found to be tightly associated with the liposomal membrane. Amino acid sequencing of the 7-, 7.5-, and 21-kDa peptides in the LH-60 eluate identified them as H(+)-ATPase fragments beginning at residues 99 or 100, 272, and 660, respectively. After further purification, the approximately 10- and 14-kDa peptides were also similarly identified as beginning at residues 272 and 660. The approximately 8-kDa fragment was purified further but could not be sequenced, presumably indicating NH2-terminal blockage. To identify which of the liposome-associated peptides are embedded in the membrane, H(+)-ATPase molecules in the proteoliposomes were labeled from the hydrophobic membrane interior with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine and cleaved with trypsin, after which the membrane-associated peptides were purified and assessed for the presence of label. The results indicate that the approximately 7-, 7.5-, and 21-kDa peptides are in contact with the lipid bilayer whereas the approximately 8-kDa peptide is not. Taken together with the results of our recent analyses of the peptides released from the proteoliposomes, this information establishes the transmembrane topography of nearly all of the 919 residues in the H(+)-ATPase molecule
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