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Statistical methods

Negiin Pourafshar, Ashkan Karimi, Xuerong Wen, Eric Sobel, Shirin Pourafshar, Nikhil Agrawal, Emma Segal, Rajesh Mohandas, Mark S Segal
Background: Monitoring of mycophenolic acid (MPA) levels may be useful for effective mycophenolate mofetil (MMF) dosing. However, whether commonly obtained trough levels are an acceptable method of surveillance remains debatable. We hypothesized that trough levels of MPA would be a poor predictor of area under the curve (AUC) for MPA. Methods: A total of 51 patients with lupus nephritis who were on MMF 1500 mg twice a day and had a 4-h AUC done were included in this study...
March 13, 2018: Nephrology, Dialysis, Transplantation
Brooke N Wolford, Cristen J Willer, Ida Surakka
The combination of Electronic Health Records (EHRs) with genetic data has ushered in the next wave of complex disease genetics. Population-based biobanks and other large cohorts provide sufficient sample sizes to identify novel genetic associations across the hundreds to thousands of phenotypes gleaned from EHRs. In this review we summarize the current state of these EHR-linked biobanks, explore ongoing methods development in the field, and highlight recent discoveries of genetic associations. We enumerate the many existing biobanks with EHRs linked to genetic data, many of which are available to researchers via application and contain sample sizes > 50,000...
March 14, 2018: Human Molecular Genetics
P D Tar, N A Thacker, M Babur, Y Watson, S Cheung, R A Little, R G Gieling, K J Williams, J P B O'Connor
Motivation: Imaging demonstrates that preclinical and human tumors are heterogeneous, i.e. a single tumor can exhibit multiple regions that behave differently during both normal development and also in response to treatment. The large variations observed in control group tumors can obscure detection of significant therapeutic effects due to the ambiguity in attributing causes of change. This can hinder development of effective therapies due to limitations in experimental design, rather than due to therapeutic failure...
March 14, 2018: Bioinformatics
Clément Niel, Christine Sinoquet, Christian Dina, Ghislain Rocheleau
Motivation: Large scale genome-wide association studies (GWAS) are tools of choice for discovering associations between genotypes and phenotypes. To date, many studies rely on univariate statistical tests for association between the phenotype and each assayed single nucleotide polymorphism (SNP). However, interaction between SNPs, namely epistasis, must be considered when tackling the complexity of underlying biological mechanisms. Epistasis analysis at large scale entails a prohibitive computational burden when addressing the detection of more than two interacting SNPs...
March 14, 2018: Bioinformatics
Mohammad Hadi Karbalaie Niya, Hossein Keyvani, Fahimeh Safarnezhad Tameshkel, Mostafa Salehi-Vaziri, Sedigheh Teaghinezhad-S, Farah Bokharaei Salim, Seyed Hamid Reza Monavari, Davod Javanmard
Human papillomavirus (HPV) is a common viral infection worldwide associated with a variety of cancers. The integration of the HPV genome in these patients causes chromosomal instability and triggers carcinogenesis. The aim of this study was to investigate the HPV-16 genome physical status in four major cancers related to HPV infection. Formalin-fixed paraffin-embedded blocks from our previous projects on head and neck, colorectal, penile, and cervical cancers were collected, and HPV-16-positive specimens were used for further analysis...
March 13, 2018: Translational Oncology
Raymond Smith, Vari Drennan, Ann Mackenzie, Nan Greenwood
BACKGROUND: Volunteer led befriending and peer support is provided to a wide range of people with varying needs. Despite large numbers of such schemes for carers of people with dementia, there is little evidence for any benefits they may offer. The aim of this research was to investigate the impact of befriending and peer support on carers of people with dementia and to explore their experiences of receiving the interventions using a mixed methods approach. METHODS: Nineteen carers of people with dementia were recruited from befriending and peer support services...
March 7, 2018: Archives of Gerontology and Geriatrics
Shushan He, Lutz Maibaum
Understanding the (de)mixing behavior of multicomponent lipid bilayers is an important step towards unraveling the nature of spatial composition heterogeneities in cellular membranes and their role in biological function. We use coarse-grained molecular dynamics simulations to study the composition phase diagram of a quaternary mixture of phospholipids and cholesterol. This mixture is known to exhibit both uniform and coexisting phases. We compare and combine different statistical measures of membrane structure to identify the onset of phase coexistence in composition space...
March 16, 2018: Journal of Physical Chemistry. B
Charalampos S Siristatidis, Eleni Sertedaki, Dennis Vaidakis, Christos Varounis, Marialena Trivella
BACKGROUND: In order to overcome the low effectiveness of assisted reproductive technologies (ART) and the high incidence of multiple births, metabolomics is proposed as a non-invasive method to assess oocyte quality, embryo viability, and endometrial receptivity, and facilitate a targeted subfertility treatment. OBJECTIVES: To evaluate the effectiveness and safety of metabolomic assessment of oocyte quality, embryo viability, and endometrial receptivity for improving live birth or ongoing pregnancy rates in women undergoing ART, compared to conventional methods of assessment...
March 16, 2018: Cochrane Database of Systematic Reviews
Jian Zhang
Transfer entropy from non-uniform embedding is a popular tool for the inference of causal relationships among dynamical subsystems. In this study we present an approach that makes use of low-dimensional conditional mutual information quantities to decompose the original high-dimensional conditional mutual information in the searching procedure of non-uniform embedding for significant variables at different lags. We perform a series of simulation experiments to assess the sensitivity and specificity of our proposed method to demonstrate its advantage compared to previous algorithms...
2018: PloS One
Siwei Chen, Ganming Deng, Kaiqun Li, Haonan Zheng, Gang Wang, Bin Yu, Kairui Zhang
BACKGROUND Previous studies demonstrated that tendon-derived stem cells (TDSCs) were vital healing cells and that mRNA expression of anti-inflammatory cytokine IL-6 was significantly upregulated in injured tendons. The aim of the present study was to investigate the effects of IL-6 on the TDSCs in vitro. MATERIAL AND METHODS TDSCs isolated from the Achilles tendons in SD rats were co-cultured with various concentrations of IL-6. Cell proliferation, cell cycle analysis, quantitative real-time PCR, western blotting analysis, and statistical analysis were used in the study...
March 16, 2018: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
Dario Graceffa, Claudio Bonifati, Viviana Lora, Pier Luigi Saraceni, Catia De Felice, Maria Sole Chimenti, Roberto Perricone, Aldo Morrone
BACKGROUND: The inflammatory involvement of the enthesis in the course of psoriasis is accompanied by structural abnormalities detectable by ultrasound. The most common of these abnormalities is the thickening of the tendon at the insertion site. AIMS: The aim of the present study was to compare the thickness of entheses of patients with psoriatic arthritis, only skin psoriasis, and healthy controls. METHODS: A cross-sectional study was conducted in a cohort of patients affected with either only skin psoriasis or psoriatic arthritis as well as in a control group...
March 16, 2018: Indian Journal of Dermatology, Venereology and Leprology
Hesham Mostafa Zakaria, Peter Joseph Massa, Richard L Smith, Tarek Hazem Moharram, John Corrigan, Ian Lee, Lonni Schultz, Jianhui Hu, Suresh Patel, Brent Griffith
Preoperative identification of the eloquent brain is important for neurosurgical planning. One common method of finding the motor cortex is by localizing "the Omega sign." No studies have tested the reliability of imaging to identify the Omega sign. We identified 40 recent and consecutive patients who had undergone preoperative functional magnetic resonance imaging for identification of the hand motor area prior to tumor resection. We recruited 11 neurosurgical residents of various levels of training and one board-certified neurosurgeon to identify the hand motor cortex Omega...
January 1, 2018: Neuroradiology Journal
Pinar Cevik, Oguz Eraslan, Kursat Eser, Suleyman Tekeli
PURPOSE: The aim of this study was to evaluate the effect of six different surface conditioning methods on the shear bond strength of ceramic brackets bonded to feldspathic porcelain. MATERIALS AND METHODS: A total of 60 feldspathic porcelain disks were fabricated and divided into six subgroups including 10 specimens in each. Specimens were first treated one of the following surface conditioning methods, namely, 37% phosphoric acid (G-H3PO4), 9.4% hydrofluoric acid (G-HF), grinding with diamond burs (G-Grinding), Nd:YAG laser (G-Nd:YAG), Airborne-particle abrasion (G-Abrasion)...
March 2018: International Journal of Artificial Organs
Sabine Hoffmann, Chantal Guihenneuc, Sophie Ancelet
Exposure measurement error can be seen as one of the most important sources of uncertainty in studies in epidemiology. When the aim is to assess the effects of measurement error on statistical inference or to compare the performance of several methods for measurement error correction, it is indispensable to be able to generate different types of measurement error. This paper compares two approaches for the generation of Berkson error, which have recently been applied in radiation epidemiology, in their ability to generate exposure data that satisfy the properties of the Berkson model...
March 15, 2018: Radiation and Environmental Biophysics
Carolina Ribeiro, Rosa Quinta, Ana Raposo, Ana Valentim, José Albuquerque, Manuela Grazina
Objective: Prospective observational study to analyze CYP2D6 pharmacogenetics in 55 Portuguese adult parturients undergoing elective cesarean section and to investigate the association between CYP2D6 alleles and pain score. Methods: DNA was extracted from peripheral blood by standard methods. Genetic analysis included allelic discrimination (CYP2D6*1, *2, *3, *4, *5, *6, *10, *17, and *41) and copy number determination with TaqMan probes by real-time polymerase chain reaction (PCR)...
March 12, 2018: Pain Medicine: the Official Journal of the American Academy of Pain Medicine
Irene E G van Hellemond, Ingeborg J H Vriens, Petronella G M Peer, Astrid C P Swinkels, Carolien H Smorenburg, Caroline M Seynaeve, Maurice J C van der Sangen, Judith R Kroep, Hiltje de Graaf, Aafke H Honkoop, Frans L G Erdkamp, Franchette W P J van den Berkmortel, Jos J E M Kitzen, Maaike de Boer, Wïlfred K de Roos, Sabine C Linn, Alexander L T Imholz, Vivianne C G Tjan-Heijnen
Background: Aromatase inhibitors (AIs) are given as adjuvant therapy for hormone receptor-positive breast cancer in postmenopausal women, also to those with chemotherapy-induced ovarian function failure. The current analysis reports on endocrine data of patients with chemotherapy-induced ovarian function failure who were included in the phase III DATA study assessing different durations of adjuvant anastrozole after tamoxifen. Methods: We identified all patients with chemotherapy-induced ovarian function failure...
December 1, 2017: Journal of the National Cancer Institute
James C Jackson, Dariush Mozaffarian, Amy J Graves, Nancy J Brown, Roberto Marchioli, Amy L Kiehl, E Wesley Ely
Background: Cognitive decline has been reported following cardiac surgery, leading to great interest in interventions to minimize its occurrence. Long-chain n-3 (ω-3) polyunsaturated fatty acids (PUFAs) have been associated with less cognitive decline in observational studies, yet no trials have tested the effects of n-3 PUFAs on cognitive decline after surgery. Objective: We sought to determine whether perioperative n-3 PUFA supplementation reduces postoperative cognitive decline in patients postcardiac surgery...
March 1, 2018: Journal of Nutrition
Selcuk Kayir, Hulya Ulusoy, Guvenc Dogan
Background/aims Sedation is one of the most important components of intensive care unit (ICU) in patients who are mechanically ventilated at intensive care conditions. As a result of sedation and analgesia in the intensive care unit, the patient is to be awakened a comfortable and easy process. The aim of the study is to demonstrate the effects of day-time sedation interruptions in intensive care patients. Material and methods We made a retrospective review of 100 patients who were monitored, mechanically ventilated and treated at our intensive care unit between January 2008 and January 2013...
January 13, 2018: Curēus
Xiaohui Chen, Yujie Deng, Yi Shi, Weifeng Zhu, Yibin Cai, Chunwei Xu, Kunshou Zhu, Xiongwei Zheng, Gang Chen, Qi Xie, Guoxing Weng
Functional inactivation of human runt-related transcription factor 3 (RUNX3) through mutation or epigenetic silencing has been well-documented in many cancerous entities. In addition to gene mutation and promoter hypermethylation, cytoplasmic mislocalization has emerged as another major manifestation of RUNX3 dysfunction in malignancies including breast, colorectal and gastric cancers. The aim of the present study was to investigate whether patients with non-small cell lung cancer (NSCLC) and different RUNX3 expression patterns would have different overall survival (OS), and the associations between different patterns of clinicopathological parameters and clinical outcome...
April 2018: Oncology Letters
Haiyan Gao, Mei Yang, Xiaolan Zhang
The present study aimed to investigate potential recurrence-risk biomarkers based on significant pathways for Luminal A breast cancer through gene expression profile analysis. Initially, the gene expression profiles of Luminal A breast cancer patients were downloaded from The Cancer Genome Atlas database. The differentially expressed genes (DEGs) were identified using a Limma package and the hierarchical clustering analysis was conducted for the DEGs. In addition, the functional pathways were screened using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses and rank ratio calculation...
April 2018: Oncology Letters
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