| 1. |
- Zaitlen, Noah, et al.
(author)
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Informed Conditioning on Clinical Covariates Increases Power in Case-Control Association Studies
- 2012
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In: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 8:11
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Journal article (peer-reviewed)abstract
- Genetic case-control association studies often include data on clinical covariates, such as body mass index (BMI), smoking status, or age, that may modify the underlying genetic risk of case or control samples. For example, in type 2 diabetes, odds ratios for established variants estimated from low-BMI cases are larger than those estimated from high-BMI cases. An unanswered question is how to use this information to maximize statistical power in case-control studies that ascertain individuals on the basis of phenotype (case-control ascertainment) or phenotype and clinical covariates (case-controlcovariate ascertainment). While current approaches improve power in studies with random ascertainment, they often lose power under case-control ascertainment and fail to capture available power increases under case-control-covariate ascertainment. We show that an informed conditioning approach, based on the liability threshold model with parameters informed by external epidemiological information, fully accounts for disease prevalence and non-random ascertainment of phenotype as well as covariates and provides a substantial increase in power while maintaining a properly controlled falsepositive rate. Our method outperforms standard case-control association tests with or without covariates, tests of gene x covariate interaction, and previously proposed tests for dealing with covariates in ascertained data, with especially large improvements in the case of case-control-covariate ascertainment. We investigate empirical case-control studies of type 2 diabetes, prostate cancer, lung cancer, breast cancer, rheumatoid arthritis, age-related macular degeneration, and end-stage kidney disease over a total of 89,726 samples. In these datasets, informed conditioning outperforms logistic regression for 115 of the 157 known associated variants investigated (P-value = 1x10(-9)). The improvement varied across diseases with a 16% median increase in chi(2) test statistics and a commensurate increase in power. This suggests that applying our method to existing and future association studies of these diseases may identify novel disease loci.
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| 2. |
- Janssen, H., et al.
(author)
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Translating the use of an enriched environment poststroke from bench to bedside: study design and protocol used to test the feasibility of environmental enrichment on stroke patients in rehabilitation
- 2012
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In: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 7:6, s. 521-526
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Journal article (peer-reviewed)abstract
- Rationale Environmental enrichment, a paradigm investigated extensively in animal models, is an intervention, which by design facilitates motor, sensory, social, and cognitive activity. It has been shown to improve poststroke motor and cognitive function in animal models of stroke. This is the first study to attempt to translate this intervention from the laboratory to the clinical setting. Aims The overall aim of this pilot study is to test the feasibility of using environmental enrichment with stroke patients in a rehabilitation setting. The aim is to enrich the environment of stroke survivors in a rehabilitation ward and measure changes in their activity (physical, cognitive, and social activity). Design Prospective nonrandomized block design intervention study. Study In the control phase we will determine the change in activity levels of patients treated in a usual rehabilitation environment over time. In the intervention phase structured observational techniques (behavioural mapping) will be used to quantify the change in activity levels of patients exposed to environmental enrichment. Outcomes The primary outcome is change in activity level. Additional data collected on entry to and exit from the study will include: cognitive function using a battery of cognitive tests, general function using the Functional Independence Measure, mood using the Patient Health Questionnaire 9 and boredom using the Stroke Rehabilitation Boredom Survey. Quality of life will be assessed using the Assessment of Quality of Life 1 month postdischarge from rehabilitation. Australian New Zealand Clinical Trials Registry# ACTRN12611000629932.
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| 3. |
- Zhukova, Nataliya, et al.
(author)
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WNT activation by lithium abrogates TP53 mutation associated radiation resistance in medulloblastoma
- 2014
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In: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 2
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Journal article (peer-reviewed)abstract
- TP53 mutations confer subgroup specific poor survival for children with medulloblastoma. We hypothesized that WNT activation which is associated with improved survival for such children abrogates TP53 related radioresistance and can be used to sensitize TP53 mutant tumors for radiation. We examined the subgroup-specific role of TP53 mutations in a cohort of 314 patients treated with radiation. TP53 wild-type or mutant human medulloblastoma cell-lines and normal neural stem cells were used to test radioresistance of TP53 mutations and the radiosensitizing effect of WNT activation on tumors and the developing brain. Children with WNT/TP53 mutant medulloblastoma had higher 5-year survival than those with SHH/TP53 mutant tumours (100% and 36.6%±8.7%, respectively (p<0.001)). Introduction of TP53 mutation into medulloblastoma cells induced radioresistance (survival fractions at 2Gy (SF2) of 89%±2% vs. 57.4%±1.8% (p<0.01)). In contrast, beta-catenin mutation sensitized TP53 mutant cells to radiation (p<0.05). Lithium, an activator of the WNT pathway, sensitized TP53 mutant medulloblastoma to radiation (SF2 of 43.5%±1.5% in lithium treated cells vs. 56.6±3% (p<0.01)) accompanied by increased number of gammaH2AX foci. Normal neural stem cells were protected from lithium induced radiation damage (SF2 of 33%±8% for lithium treated cells vs. 27%±3% for untreated controls (p=0.05). Poor survival of patients with TP53 mutant medulloblastoma may be related to radiation resistance. Since constitutive activation of the WNT pathway by lithium sensitizes TP53 mutant medulloblastoma cells and protect normal neural stem cells from radiation, this oral drug may represent an attractive novel therapy for high-risk medulloblastomas.
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| 4. |
- Giraldez, Roberto R., et al.
(author)
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Prevalence and clinical outcomes of undiagnosed diabetes mellitus and prediabetes among patients with high-risk non-ST-segment elevation acute coronary syndrome
- 2013
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In: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 165:6, s. 918-925.e2
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Journal article (peer-reviewed)abstract
- Background We examined the prevalence of undiagnosed diabetes or prediabetes and associations with ischemic outcomes among non-ST-segment elevation acute coronary syndrome (ACS) patients. Methods We categorized 8795 EARLY ACS trial patients into one of the following groups: "known diabetes" (n = 2860 [32.5%]; reported on the case report form), "undiagnosed diabetes" (n = 1069 [12.2%]; no diabetes history and fasting glucose >= 126 mg/dL or hemoglobin A(1c) >= 6.5%), "prediabetes" (n = 947 [10.8%]; fasting glucose >= 110 to <126 mg/dL, or " normal" (n = 3919 [44.5%]). Adjusted associations of known diabetes, undiagnosed diabetes, and prediabetes (versus normal) with 30-day and 1-year outcomes were determined. Results Undiagnosed diabetes was associated with greater 30-day death or myocardial infarction (MI) (ORadj 1.28, 95% CI 1.05-1.57), driven primarily by greater 30-day mortality (ORadj 1.65, 95% CI 1.09-2.48). Known diabetic patients had 30-day death or MI outcomes similar to those of normal patients, but 30-day mortality was higher (ORadj 1.40, 95% CI 1.01-1.93). Prediabetic patients had 30-day death or MI outcomes similar to those of normal patients. One-year mortality was greater among known diabetic patients (HRadj 1.38, 95% CI 1.13-1.67) but not among those with undiagnosed diabetes or prediabetes. Conclusions Undiagnosed diabetes and prediabetes were common among high-risk non-ST-segment elevation ACS patients. Routine screening for undiagnosed diabetes may be useful since these patients seem to have worse short-term outcomes and deserve consideration of alternative management strategies.
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| 6. |
- Levänen, Bettina, et al.
(author)
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Altered microRNA profiles in bronchoalveolar lavage fluid exosomes in asthmatic patients.
- 2013
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In: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 131:3, s. 894-903
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Journal article (peer-reviewed)abstract
- BACKGROUND: Asthma is characterized by increased airway narrowing in response to nonspecific stimuli. The disorder is influenced by both environmental and genetic factors. Exosomes are nanosized vesicles of endosomal origin released from inflammatory and epithelial cells that have been implicated in asthma. In this study we characterized the microRNA (miRNA) content of exosomes in healthy control subjects and patients with mild intermittent asthma both at unprovoked baseline and in response to environmental challenge.OBJECTIVE: To investigate alterations in bronchoalveolar lavage fluid (BALF) exosomal miRNA profiles due to asthma, and following subway air exposure.METHODS: Exosomes were isolated from BALF from healthy control subjects (n = 10) and patients with mild intermittent asthma (n = 10) after subway and control exposures. Exosomal RNA was analyzed by using microarrays containing probes for 894 human miRNAs, and selected findings were validated with quantitative RT-PCR. Results were analyzed by using multivariate modeling.RESULTS: The presence of miRNAs was confirmed in exosomes from BALF of both asthmatic patients and healthy control subjects. Significant differences in BALF exosomal miRNA was detected for 24 miRNAs with a subset of 16 miRNAs, including members of the let-7 and miRNA-200 families, providing robust classification of patients with mild nonsymptomatic asthma from healthy subjects with 72% cross-validated predictive power (Q(2) = 0.72). In contrast, subway exposure did not cause any significant alterations in miRNA profiles.CONCLUSION: These studies demonstrate substantial differences in exosomal miRNA profiles between healthy subjects and patients with unprovoked, mild, stable asthma. These changes might be important in the inflammatory response leading to bronchial hyperresponsiveness and asthma.
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| 7. |
- Mellgren, A., et al.
(author)
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Long-term efficacy of NASHA Dx injection therapy for treatment of fecal incontinence
- 2014
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In: Neurogastroenterology and Motility. - : Wiley. - 1350-1925 .- 1365-2982. ; 26:8, s. 1087-1094
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Journal article (peer-reviewed)abstract
- Background Injectable bulking treatment for fecal incontinence (FI) is intended to expand tissue in the anal canal and prevent fecal leakage. Use of injectable bulking agents is increasing because it can be performed in an outpatient setting and with low risk for morbidity. This study evaluated the long-term (36-month) clinical effectiveness and safety of injection of non-animal stabilized hyaluronic acid/dextranomer (NASHA Dx) on FI symptoms. Methods In a prospective multicenter trial, 136 patients with FI received the NASHA Dx bulking agent. Treatment success defined as a reduction in number of FI episodes by 50% or more compared with baseline (Responder(50)). Change from baseline in Cleveland Clinic Florida Fecal Incontinence Score (CCFIS) and Fecal Incontinence Quality of Life Scale (FIQL), and adverse events were also evaluated. Key Results Successful decrease in symptoms was achieved in 52% of patients at 6 months and this was sustained at 12 months (57%) and 36 months (52%). Mean CCFIS decreased from 14 at baseline to 11 at 36 months (p < 0.001). Quality-of-life scores for all four domains improved significantly between baseline and 36 months of follow-up. Severe adverse events were rare and most adverse events were transient and pertained to minor bleeding and pain or discomfort. Conclusions & Inferences Submucosal injection of NASHA Dx provided a significant improvement of FI symptoms in a majority of patients and this effect was stable during the course of the follow-up and maintained for 3 years.
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