607 research outputs found
The aromatase inhibitor letrozole enhances the effect of doxorubicin and docetaxel in an MCF7 cell line model
Introduction: Post-menopausal women with estrogen receptor (ER) positive breast cancer receive adjuvant chemotherapy and endocrine therapy sequentially since tamoxifen may antagonise the cytotoxicity of chemotherapy drugs. With increased use of aromatase inhibitors (AIs) in place of tamoxifen, the potential use of concomitant chemo-endocrine treatments with the AI letrozole, before clinical trials are undertaken, requires evaluation.
Methods: MCF7-aro cells expressing the aromatase gene were treated with letrozole, doxorubicin and docetaxel. The effects of different drug concentrations, drug combinations and scheduling on cytotoxicity and aromatase activity were investigated. Key receptor, cell cycle regulation and apoptosis proteins were examined by immunoblotting.
Results: Administration of letrozole with either doxorubicin or docetaxel resulted in increased levels of cytotoxicity under all treatment schedules (add in, sequential or simultaneous drug administration) with the greatest anti-proliferative effect observed using concomitant treatment (letrozole first with chemotherapy added in). The inhibitory effect of letrozole on aromatase activity was unchanged by the addition of doxorubicin or docetaxel. Letrozole treatment resulted in decreased HER2 expression and addition of doxorubicin and docetaxel to letrozole led to elevated ER-Ă levels.
Conclusions: In vitro, letrozole, unlike tamoxifen, enhances the cytotoxicity of both doxorubicin and docetaxel. This supports the prospect of trials using letrozole with chemotherapy in postmenopausal women with ER positive breast cancer
Factors associated with the presence of diabetic ketoacidosis at diagnosis of diabetes in children and young adults: a systematic review
Objective To identify the factors associated with diabetic ketoacidosis at diagnosis of type 1 diabetes in children and young adults
Patient-Centered Outcomes From Multiparametric MRI and MRI-Guided Biopsy for Prostate Cancer: A Systematic Review.
OBJECTIVE: To identify and characterize patient-centered outcomes (PCOs) relating to multiparametric MRI (mpMRI) and MRI-guided biopsy as diagnostic tests for possible prostate cancer. METHODS: Medline via OVID, EMBASE, PsycInfo, and the Cochrane Central register of Controlled Trials (CENTRAL) were searched for relevant articles. Hand searching of reference lists and snowballing techniques were performed. Studies of mpMRI and MRI-guided biopsy that measured any PCO were included. There were no restrictions placed on year of publication, language, or country for study inclusion. All database search hits were screened independently by two reviewers, and data were extracted using a standardized form. RESULTS: Overall, 2,762 database search hits were screened based on title and abstract. Of these, 222 full-text articles were assessed, and 10 studies met the inclusion criteria. There were 2,192 participants featured in the included studies, all of which were conducted in high-income countries. Nineteen different PCOs were measured, with a median of four PCOs per study (range 1-11). Urethral bleeding, pain, and urinary tract infection were the most common outcomes measured. In the four studies that compared mpMRI or MRI-guided biopsy to transrectal ultrasound biopsy, most adverse outcomes occurred less frequently in MRI-related tests. These four studies were assessed as having a low risk of bias. DISCUSSION: PCOs measured in studies of mpMRI or MRI-guided biopsy thus far have mostly been physical outcomes, with some evidence that MRI tests are associated with less frequent adverse outcomes compared with transrectal ultrasound biopsy. There was very little evidence for the effect of mpMRI and MRI-guided biopsy on emotional, cognitive, social, or behavioral outcomes
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A review of the factors that influence pesticide residues in pollen and nectar: future research requirements for optimising the estimation of pollinator exposure
In recent years, the impact of Plant Protection Products (PPPs) on insect pollinator decline has stimulated significant amounts of research, as well as political and public interest. PPP residues have been found in various bee-related matrices, resulting in governmental bodies worldwide releasing guidance documents on methods for the assessment of the overall risk of PPPs to different bee species. An essential part of these risk assessments are PPP residues found in pollen and nectar, as they represent a key route of exposure. However, PPP residue values in these matrices exhibit large variations and are not available for many PPPs and crop species combinations, which results in inaccurate estimations and uncertainties in risk evaluation. Additionally, residue studies on pollen and nectar are expensive and practically challenging. An extrapolation between different cropping scenarios and PPPs is not yet justified, as the behaviour of PPPs in pollen and nectar is poorly understood. Therefore, this review aims to contribute to a better knowledge and understanding of the fate of PPP residues in pollen and nectar and to outline knowledge gaps and future research needs. The literature suggests that four primary factors, the crop type, the application method, the physicochemical properties of a compound and the environmental conditions have the greatest influence on PPP residues in pollen and nectar. However, these factors consist of many sub-factors and initial effects may be disguised by different sampling methodologies, impeding their exact characterisation. Moreover, knowledge about these factors is ambiguous and restricted to a few compounds and plant species. We propose that future research should concentrate on identifying relationships and common features amongst various PPP applications and crops, as well as an overall quantification of the described parameters; in order to enable a reliable estimation of PPP residues in pollen, nectar and other bee matrices
The pathway to diagnosis of type 1 diabetes in children: a questionnaire study.
OBJECTIVE: To explore the pathway to diagnosis of type 1 diabetes (T1D) in children. DESIGN: Questionnaire completed by parents. PARTICIPANTS: Parents of children aged 1â
month to 16â
years diagnosed with T1D within the previous 3â
months. SETTING: Children and parents from 11 hospitals within the East of England. RESULTS: 88/164 (54%) invited families returned the questionnaire. Children had mean±SD age of 9.41±4.5â
years. 35 (39.8%) presented with diabetic ketoacidosis at diagnosis. The most common symptoms were polydipsia (97.7%), polyuria (83.9%), tiredness (75.9%), nocturia (73.6%) and weight loss (64.4%) and all children presented with at least one of those symptoms. The time from symptom onset to diagnosis ranged from 2 to 315â
days (median 25â
days). Most of this was the appraisal interval from symptom onset until perceiving the need to seek medical advice. Access to healthcare was good but one in five children presenting to primary care were not diagnosed at first encounter, most commonly due to waiting for fasting blood tests or alternative diagnoses. Children diagnosed at first consultation had a shorter duration of symptoms (p=0.022) and children whose parents suspected the diagnosis were 1.3 times more likely (relative risk (RR) 1.3, 95% CI 1.02 to 1.67) to be diagnosed at first consultation. CONCLUSIONS: Children present with the known symptoms of T1D but there is considerable scope to improve the diagnostic pathway. Future interventions targeted at parents need to address the tendency of parents to find alternative explanations for symptoms and the perceived barriers to access, in addition to symptom awareness.The study was funded by the Royal College of General Practitioners Scientific Foundation Board (SFB-2011-15). JUS was supported by a National Institute of Health Research (NIHR) Academic Clinical Fellowship and subsequently Clinical Lectureship, and FMW by an NIHR Clinician Scientist award. SJS was supported by the Medical Research Council www.mrc.ac.uk [Unit Programme number MC_UU_12015/1]. The views expressed in this publication are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.This is the final version of the article. It was first published by BMJ Group at http://bmjopen.bmj.com/content/5/3/e006470.ful
Identity-by-descent estimation with population- and pedigree-based imputation in admixed family data
Background: In the past few years, imputation approaches have been mainly used in population-based designs of genome-wide association studies, although both family- and population-based imputation methods have been proposed. With the recent surge of family-based designs, family-based imputation has become more important. Imputation methods for both designs are based on identity-by-descent (IBD) information. Apart from imputation, the use of IBD information is also common for several types of genetic analysis, including pedigree-based linkage analysis.
Methods: We compared the performance of several family- and population-based imputation methods in large pedigrees provided by Genetic Analysis Workshop 19 (GAW19). We also evaluated the performance of a new IBD mapping approach that we propose, which combines IBD information from known pedigrees with information from unrelated individuals.
Results: Different combinations of the imputation methods have varied imputation accuracies. Moreover, we showed gains from the use of both known pedigrees and unrelated individuals with our IBD mapping approach over the use of known pedigrees only.
Conclusions: Our results represent accuracies of different combinations of imputation methods that may be useful for data sets similar to the GAW19 pedigree data. Our IBD mapping approach, which uses both known pedigree and unrelated individuals, performed better than classical linkage analysis
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Risk Prediction Models for Colorectal Cancer Incorporating Common Genetic Variants: A Systematic Review.
Colorectal cancer screening reduces colorectal cancer incidence and mortality. Risk models based on phenotypic variables have relatively good discrimination in external validation and may improve efficiency of screening. Models incorporating genetic variables may perform better. In this review, we updated our previous review by searching Medline and EMBASE from the end date of that review (January 2014) to February 2019 to identify models incorporating at least one SNP and applicable to asymptomatic individuals in the general population. We identified 23 new models, giving a total of 29. Of those in which the SNP selection was on the basis of published genome-wide association studies, in external or split-sample validation the AUROC was 0.56 to 0.57 for models that included SNPs alone, 0.61 to 0.63 for SNPs in combination with other risk factors, and 0.56 to 0.70 when age was included. Calibration was only reported for four. The addition of SNPs to other risk factors increases discrimination by 0.01 to 0.06. Public health modeling studies suggest that, if determined by risk models, the range of starting ages for screening would be several years greater than using family history alone. Further validation and calibration studies are needed alongside modeling studies to assess the population-level impact of introducing genetic risk-based screening programs
Variation in the initial assessment and investigation for ovarian cancer in symptomatic women: a systematic review of international guidelines
Abstract: Background: Women with ovarian cancer can present with a variety of symptoms and signs, and an increasing range of tests are available for their investigation. A number of international guidelines provide advice for the initial assessment of possible ovarian cancer in symptomatic women. We systematically identified and reviewed the consistency and quality of these documents. Methods: MEDLINE, Embase, guideline-specific databases and professional organisation websites were searched in March 2018 for relevant clinical guidelines, consensus statements and clinical pathways, produced by professional or governmental bodies. Two reviewers independently extracted data and appraised documents using the Appraisal for Guidelines and Research Evaluation 2 (AGREEII) tool. Results: Eighteen documents from 11 countries in six languages met selection criteria. Methodological quality varied with two guidance documents achieving an AGREEII score â„ 50% in all six domains and 10 documents scoring â„50% for âRigour of developmentâ (range: 7â96%). All guidance documents provided advice on possible symptoms of ovarian cancer, although the number of symptoms included in documents ranged from four to 14 with only one symptom (bloating/abdominal distension/increased abdominal size) appearing in all documents. Fourteen documents provided advice on physical examinations but varied in both the examinations they recommended and the physical signs they included. Fifteen documents provided recommendations on initial investigations. Transabdominal/transvaginal ultrasound and the serum biomarker CA125 were the most widely advocated initial tests. Five distinct testing strategies were identified based on the number of tests and the order of testing advocated: âsingle testâ, âdual testingâ, âsequential testingâ, âmultiple testing optionsâ and âno testingâ. Conclusions: Recommendations on the initial assessment and investigation for ovarian cancer in symptomatic women vary considerably between international guidance documents. This variation could contribute to differences in the way symptomatic women are assessed and investigated between countries. Greater research is needed to evaluate the assessment and testing approaches advocated by different guidelines and their impact on ovarian cancer detection
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