598 research outputs found
Nonsteroidal Anti-Inflammatory Drugs and Risk of Melanoma
Because nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit tumor growth in vitro, we investigated the association between NSAIDs and melanoma to determine if there was epidemiologic evidence of a chemopreventive effect from these medications. Three hundred twenty-seven subjects with incident melanoma and 119 melanoma-free controls completed a structured interview assessing melanoma risk factors. The unadjusted odds ratio (OR) for use of nonaspirin NSAIDs was 0.58 (95% CI 0.31–1.11), in a comparison of subjects with melanoma to controls. After adjustment for melanoma risk factors, the OR was 0.71 (95% CI 0.23–2.02). Aspirin users had an unadjusted OR of 0.85 (95% CI 0.45–1.69) and an adjusted OR of 1.45 (95% CI 0.44–4.74). In this pilot study, we found no evidence of a significant association between analgesic use and melanoma risk when potential confounders are assessed. Based on conflicting reports in the literature, meta-analysis may be appropriate
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Relative Roles of Race Versus Socioeconomic Position in Studies of Health Inequalities: A Matter of Interpretation
An abundance of research has documented health inequalities by race and socioeconomic position (SEP) in the United States. However, conceptual and methodological challenges complicate the interpretation of study findings, thereby limiting progress in understanding health inequalities and in achieving health equity. Fundamental to these challenges is a lack of clarity about what race is and the implications of that ambiguity for scientific inquiry. Additionally, there is wide variability in how SEP is conceptualized and measured, resulting in a lack of comparability across studies and significant misclassification of risk. The objectives of this review are to synthesize the literature regarding common approaches to examining race and SEP health inequalities and to discuss the conceptual and methodological challenges associated with how race and SEP have been employed in public health research. Addressing health inequalities has become increasingly important as the United States trends toward becoming a majority-minority nation. Recommendations for future research are presented
The Advanced Automated Directional Solidification Furnace
The Advanced Automated Directional Solidification Furnace (AADSF) is a five zone tubular furnace designed for Bridgman-Stockbarger, other techniques of crystal growth involving multiple temperature zones such as vapor transport experiments and other materials science experiments. The five zones are primarily designed to produce uniform hot and cold temperature regions separated by an adiabatic region constructed of a heat extraction plate and an insert to reduce radiation from the hot to the cold zone. The hot and cold zone temperatures are designed to reach 1600 C and 1100 C, respectively. AADSF operates on a Multi-Purpose Experiment Support Structure (MPESS) within the cargo bay of the Space Shuttle on the United States Microgravity Payload (USMP) missions. Two successful flights, both employing the directional solidification or Bridgman Stockbarger technique for crystal growth have been made, and crystals of HgCdTe and PbSnTe grown in microgravity have been produced on USMP-2 and USMP-3, respectively. The addition of a Sample Exchange Mechanism (SEM) will enable three different samples to be processed on future flights including the USMP-4 mission
Disparities in hypertension and cardiovascular disease in blacks: The critical role of medication adherence
Blacks are two to three times as likely as whites to die of preventable heart disease and stroke. Declines in mortality from heart disease have not eliminated racial disparities. Control and effective treatment of hypertension, a leading cause of cardiovascular disease, among blacks is less than in whites and remains a challenge. One of the driving forces behind this racial/ethnic disparity is medication nonadherence whose cause is embedded in social determinants. Eight practical approaches to addressing medication adherence with the potential to attenuate disparities were identified and include: (1) patient engagement strategies, (2) consumer-directed health care, (3) patient portals, (4) smart apps and text messages, (5) digital pillboxes, (6) pharmacist-led engagement, (7) cardiac rehabilitation, and (8) cognitive-based behavior. However, while data suggest that these strategies may improve medication adherence, the effect on ameliorating racial/ethnic disparities is not certain. This review describes the relationship between disparities and medication adherence, which likely plays a role in persistent disparities in cardiovascular morbidity and mortality
Genetic Evaluation for Hereditary Cancer Syndromes Among African Americans: A Critical Review
While hereditary cancer syndromes have been described and studied for centuries, the completion of the human genome project fueled accelerated progress in precision medicine due to the introduction of genetic testing in the 1990s, creating avenues for tailored treatments and medical management options. However, genetic testing has not benefited everyone equitably, with nearly all of the published work based on individuals of non-Hispanic White/European ancestry. There remains a gap in knowledge regarding the prevalence, penetrance, and manifestations of common hereditary cancer syndromes in the African-American population due to significant disparities in access and uptake of genetic testing. This review summarizes the available literature on genetic testing for breast, colon, and prostate cancers in the African-American population and explores the disparities in access to genetic testing between non-Hispanic White and African-American patients. This article also addresses the barriers to genetic testing and discrepancies in the uptake of recommendations for hereditary cancer syndromes in the African-American population when compared with non-Hispanic Whites. The review offers practice implications for many healthcare providers and demonstrates gaps in the existing knowledge to be addressed in future studies to help eliminate the persisting health disparities faced by the African-American population
Geometric origin of mechanical properties of granular materials
Some remarkable generic properties, related to isostaticity and potential
energy minimization, of equilibrium configurations of assemblies of rigid,
frictionless grains are studied. Isostaticity -the uniqueness of the forces,
once the list of contacts is known- is established in a quite general context,
and the important distinction between isostatic problems under given external
loads and isostatic (rigid) structures is presented. Complete rigidity is only
guaranteed, on stability grounds, in the case of spherical cohesionless grains.
Otherwise, the network of contacts might deform elastically in response to load
increments, even though grains are rigid. This sets an uuper bound on the
contact coordination number. The approximation of small displacements (ASD)
allows to draw analogies with other model systems studied in statistical
mechanics, such as minimum paths on a lattice. It also entails the uniqueness
of the equilibrium state (the list of contacts itself is geometrically
determined) for cohesionless grains, and thus the absence of plastic
dissipation. Plasticity and hysteresis are due to the lack of such uniqueness
and may stem, apart from intergranular friction, from small, but finite,
rearrangements, in which the system jumps between two distinct potential energy
minima, or from bounded tensile contact forces. The response to load increments
is discussed. On the basis of past numerical studies, we argue that, if the ASD
is valid, the macroscopic displacement field is the solution to an elliptic
boundary value problem (akin to the Stokes problem).Comment: RevTex, 40 pages, 26 figures. Close to published paper. Misprints and
minor errors correcte
Phase I Study of Celecoxib with Concurrent Irinotecan, Cisplatin, and Radiation Therapy for Patients with Unresectable Locally Advanced Non-Small Cell Lung Cancer
Purpose: Preclinical findings suggest that adding targeted therapies to combination radiation-chemotherapy can enhance treatment efficacy; however, this approach may enhance normal tissue toxicity. We investigated the maximum tolerated dose, dose-limiting toxicities, and response rate when the selective cyclooxygenase-2 inhibitor celecoxib is added to concurrent irinotecan, cisplatin, and radiation therapy for patients with inoperable stage II–III non-small cell lung cancer (NSCLC). Methods and Materials: Eighteen patients were analyzed in a phase I clinical dose-escalation trial. Celecoxib was given daily beginning 5 days before radiation followed by maintenance doses for 12 weeks. Toxicity was graded with the Common Terminology Criteria for Adverse Events V3.0 and response with the World Health Organization system. Primary endpoints were maximum tolerated dose of celecoxib and treatment toxicity; secondary endpoints were response and survival rates. Results: The maximum tolerated dose of celecoxib was not reached, in part owing to discontinuation of the drug supply. At doses of 200 or 400 mg/day, no patients experienced any dose-limiting toxicity (acute grade ≥4 esophagitis or pneumonitis, neutropenic fever or thrombocytopenia requiring transfusion, or acute grade ≥3 diarrhea). Grade 3 toxicities were leukopenia (five patients), fatigue (3), pneumonitis (2), dyspnea (1), pain (1), and esophageal stricture (1). Interestingly, pulmonary fibrosis (a late toxicity) was no more severe in the higher-dose (400-mg) group and may have been less common than in the lower-dose group. The clinical response rate was 100% (8 complete, 10 partial). Two-year rates were: overall survival 65%; local-regional control 69%; distant metastasis-free survival 71%; and disease-free survival 64%. Conclusion: Although preliminary, our results suggest that adding celecoxib to concurrent chemoradiation for inoperable NSCLC is safe and can improve outcome without increasing normal tissue toxicity
Deficiency in the endocytic adaptor proteins PHETA1/2 impairs renal and craniofacial development
A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the in vivo functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain-containing endocytic trafficking adaptor 1 and 2 (PHETA1/2; also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of OCRL, the causative gene for Lowe syndrome. Here, we conducted the first study of PHETA1/2 in vivo, utilizing the zebrafish system. We found that impairment of both zebrafish orthologs, pheta1 and pheta2, disrupted endocytosis and ciliogenesis in renal tissues. In addition, pheta1/2 mutant animals exhibited reduced jaw size and delayed chondrocyte differentiation, indicating a role in craniofacial development. Deficiency of pheta1/2 resulted in dysregulation of cathepsin K, which led to an increased abundance of type II collagen in craniofacial cartilages, a marker of immature cartilage extracellular matrix. Cathepsin K inhibition rescued the craniofacial phenotypes in the pheta1/2 double mutants. The abnormal renal and craniofacial phenotypes in the pheta1/2 mutant animals were consistent with the clinical presentation of a patient with a de novo arginine (R) to cysteine (C) variant (R6C) of PHETA1. Expressing the patient-specific variant in zebrafish exacerbated craniofacial deficits, suggesting that the R6C allele acts in a dominant-negative manner. Together, these results provide insights into the in vivo roles of PHETA1/2 and suggest that the R6C variant is contributory to the pathogenesis of disease in the patient
Snail1 induces epithelial-to-mesenchymal transition and tumor initiating stem cell characteristics
<p>Abstract</p> <p>Background</p> <p>Tumor initiating stem-like cells (TISCs) are a subset of neoplastic cells that possess distinct survival mechanisms and self-renewal characteristics crucial for tumor maintenance and propagation. The induction of epithelial-mesenchymal-transition (EMT) by TGFβ has been recently linked to the acquisition of TISC characteristics in breast cancer. In HCC, a TISC and EMT phenotype correlates with a worse prognosis. In this work, our aim is to elucidate the underlying mechanism by which cells acquire tumor initiating characteristics after EMT.</p> <p>Methods</p> <p>Gene and protein expression assays and Nanog-promoter luciferase reporter were utilized in epithelial and mesenchymal phenotype liver cancer cell lines. EMT was analyzed with migration/invasion assays. TISC characteristics were analyzed with tumor-sphere self-renewal and chemotherapy resistance assays. <it>In vivo </it>tumor assay was performed to investigate the role of Snail1 in tumor initiation.</p> <p>Conclusion</p> <p>TGFβ induced EMT in epithelial cells through the up-regulation of Snail1 in Smad-dependent signaling. Mesenchymal liver cancer post-EMT demonstrates TISC characteristics such as tumor-sphere formation but are not resistant to cytotoxic therapy. The inhibition of <it>Snail1 </it>in mesenchymal cells results in decreased <it>Nanog </it>promoter luciferase activity and loss of self-renewal characteristics <it>in vitro</it>. These changes confirm the direct role of Snail1 in some TISC traits. <it>In vivo</it>, the down-regulation of <it>Snail1 </it>reduced tumor growth but was not sufficient to eliminate tumor initiation. In summary, TGFβ induces EMT and TISC characteristics through Snail1 and Nanog up-regulation. In mesenchymal cells post-EMT, Snail1 directly regulates <it>Nanog </it>expression, and loss of Snail1 regulates tumor growth without affecting tumor initiation.</p
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