77 research outputs found

    Education, Job Requirements, and Commuting: An Analysis of Network Flows

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    By now measures of employment "access" and "potential" have been widely diffused in the literature on regional economics and transport planning. Pooler (1995) gives a brief review of accessibility measures, indicating that these concepts date back to the 1930s. According to standard economic intuition, the employment access of a residential area increases with its proximity to concentrations of employment opportunities. The various indices of accessibility which have been proposed merely formalize and quantify this notion

    Amyloid accelerates tau propagation and toxicity in a model of early Alzheimer's disease

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    Introduction: In early stages of Alzheimer’s disease (AD), neurofibrillary tangles (NFT) are largely restricted to the entorhinal cortex and medial temporal lobe. At later stages, when clinical symptoms generally occur, NFT involve widespread limbic and association cortices. At this point in the disease, amyloid plaques are also abundantly distributed in the cortex. This observation from human neuropathological studies led us to pose two alternative hypotheses: that amyloid in the cortex is permissive for the spread of tangles from the medial temporal lobe, or that these are co-occurring but not causally related events simply reflecting progression of AD pathology. Results: We now directly test the hypothesis that cortical amyloid acts as an accelerant for spreading of tangles beyond the medial temporal lobe. We crossed rTgTauEC transgenic mice that demonstrate spread of tau from entorhinal cortex to other brain structures at advanced age with APP/PS1 mice, and examined mice with either NFTs, amyloid pathology, or both. We show that concurrent amyloid deposition in the cortex 1) leads to a dramatic increase in the speed of tau propagation and an extraordinary increase in the spread of tau to distal brain regions, and 2) significantly increases tau-induced neuronal loss. Conclusions: These data strongly support the hypothesis that cortical amyloid accelerates the spread of tangles throughout the cortex and amplifies tangle-associated neural system failure in AD. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0199-x) contains supplementary material, which is available to authorized users

    Clonal hematopoiesis and risk of prostate cancer in large samples of European ancestry men.

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    Little is known regarding the potential relationship between clonal hematopoiesis (CH) of indeterminate potential (CHIP), which is the expansion of hematopoietic stem cells with somatic mutations, and risk of prostate cancer, the fifth leading cause of cancer death of men worldwide. We evaluated the association of age-related CHIP with overall and aggressive prostate cancer risk in two large whole-exome sequencing studies of 75 047 European ancestry men, including 7663 prostate cancer cases, 2770 of which had aggressive disease, and 3266 men carrying CHIP variants. We found that CHIP, defined by over 50 CHIP genes individually and in aggregate, was not significantly associated with overall (aggregate HR = 0.93, 95% CI = 0.76-1.13, P = 0.46) or aggressive (aggregate OR = 1.14, 95% CI = 0.92-1.41, P = 0.22) prostate cancer risk. CHIP was weakly associated with genetic risk of overall prostate cancer, measured using a polygenic risk score (OR = 1.05 per unit increase, 95% CI = 1.01-1.10, P = 0.01). CHIP was not significantly associated with carrying pathogenic/likely pathogenic/deleterious variants in DNA repair genes, which have previously been found to be associated with aggressive prostate cancer. While findings from this study suggest that CHIP is likely not a risk factor for prostate cancer, it will be important to investigate other types of CH in association with prostate cancer risk

    How patient participation was used to develop a questionnaire that is fit for purpose for assessing quality of life in severe asthma.

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    BACKGROUND: Previous research shows that existing asthma quality of life questionnaires fail to measure the burden of oral corticosteroids that can be used to treat severe asthma, and are therefore not fit for purpose for severe asthma according to the USA's Federal Drug Authority's (FDA) criteria for content validity. Patient input and documentation of that input is key to achieving content validity according to FDA guidelines. This paper describes the process of constructing a new questionnaire to measure the burden of asthma symptoms and burden of treatment in severe asthma, using criteria specified by the FDA. METHODS: A draft severe asthma questionnaire (SAQ) was constructed using qualitative input from severe asthma patients who took part in an earlier study. The aim of this study was to improve that draft questionnaire using a further group of patients. In four iterative focus groups, 16 people with severe asthma completed the draft questionnaire, discussed the wording and structure and suggested changes that were incorporated into the final version. RESULTS: The original intention to ask patients to identify whether problems were caused by asthma symptoms or side effects of medication was abandoned as the attribution of cause was found to be difficult and inconsistent. The recall period of 2 weeks was acceptable but fails to reflect the patients' desire to express the variability of severe asthma. Patients suggested improvements to the wording of the draft questionnaire, including splitting some items in two, combining two items in one, and changes to some of the words in individual items and the response scale. CONCLUSIONS: The final version of the questionnaire was substantially different from one constructed using only qualitative reports from patients about the quality of life deficits of severe asthma. Patients make a valuable contribution to the questionnaire if they are asked to comment and improve an initial draft and where patients are treated as partners in the process of questionnaire construction, rather than only as a source of information to experts who construct the questionnaire

    A qualitative investigation of lived experiences of long-term health condition management with people who are food insecure.

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    Background: As more people are living with one or more chronic health conditions, supporting patients to become activated, self-managers of their conditions has become a key health policy focus both in the UK and internationally. There is also growing evidence in the UK that those with long term health conditions have an increased risk of being food insecure. While international evidence indicates that food insecurity adversely affects individual's health condition management capability, little is known about how those so affected manage their condition(s) in this context. An investigation of lived experience of health condition management was undertaken with food insecure people living in north east Scotland. The study aimed to explore the challenges facing food insecure people in terms of, i. their self-care condition management practices, and ii. disclosing and discussing the experience of managing their condition with a health care professional, and iii. Notions of the support they might wish to receive from them. Methods: Twenty in-depth interviews were conducted with individuals attending a food bank and food pantry in north east Scotland. Interview audio recordings were fully transcribed and thematically analysed. Results: Individuals reporting multiple physical and mental health conditions, took part in the study. Four main themes were identified i.e.: 1. food practices, trade-offs and compromises, that relate to economic constraints and lack of choice; 2. illness experiences and food as they relate to physical and mental ill-health; 3. (in) visibility of participants' economic vulnerability within health care consultations; and 4. perceptions and expectations of the health care system. Conclusions: This study, the first of its kind in the UK, indicated that participants' health condition management aspirations were undermined by the experience of food insecurity, and that their health care consultations in were, on the whole, devoid of discussions of those challenges. As such, the study indicated practical and ethical implications for health care policy, practice and research associated with the risk of intervention-generated health inequalities that were suggested by this study. Better understanding is needed about the impact of household food insecurity on existing ill health, wellbeing and health care use across the UK

    The associations between Parkinson’s disease and cancer: the plot thickens

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    Two Novel Susceptibility Loci for Prostate Cancer in Men of African Ancestry.

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    Prostate cancer incidence is 1.6-fold higher in African Americans than in other populations. The risk factors that drive this disparity are unknown and potentially consist of social, environmental, and genetic influences. To investigate the genetic basis of prostate cancer in men of African ancestry, we performed a genome-wide association meta-analysis using two-sided statistical tests in 10 202 case subjects and 10 810 control subjects. We identified novel signals on chromosomes 13q34 and 22q12, with the risk-associated alleles found only in men of African ancestry (13q34: rs75823044, risk allele frequency = 2.2%, odds ratio [OR] = 1.55, 95% confidence interval [CI] = 1.37 to 1.76, P = 6.10 × 10-12; 22q12.1: rs78554043, risk allele frequency = 1.5%, OR = 1.62, 95% CI = 1.39 to 1.89, P = 7.50 × 10-10). At 13q34, the signal is located 5' of the gene IRS2 and 3' of a long noncoding RNA, while at 22q12 the candidate functional allele is a missense variant in the CHEK2 gene. These findings provide further support for the role of ancestry-specific germline variation in contributing to population differences in prostate cancer risk
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