477 research outputs found

    The Bernstein problem for intrinsic graphs in Heisenberg groups and calibrations

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    In this paper we deal with some problems concerning minimal hypersurfaces in Carnot-Caratheodory (CC) structures. More precisely we will introduce a general calibration method in this setting and we will study the Bernstein problem for entire regular intrinsic minimal graphs in a meaningful and simpler class of CC spaces, i.e. the Heisenberg group H^n. In particular we will positively answer to the Bernstein problem in the case n=1 and we will provide counterexamples when n>=5

    [Accepted Manuscript] Cancer subtypes in aetiological research.

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    Researchers often attempt to categorize tumors into more homogeneous subtypes to better predict prognosis or understand pathogenic mechanisms. In clinical research, typically the focus is on prognosis: the tumor subtypes are intended to be associated with specific responses to treatment and/or different clinical outcomes. In aetiological research, the focus is on identifying distinct pathogenic mechanisms, which may involve different risk factors. We used directed acyclic graphs to present a framework for considering potential biases arising in aetiological research of tumor subtypes, when there is incomplete correspondence between the identified subtypes and the underlying pathogenic mechanisms. We identified two main scenarios: (1) weak effect, when the tumor subtypes are identified through combinations of characteristics and some of these characteristics are affected by factors that are unrelated with the underlying pathogenic mechanisms; and (2) lack of causality, when the set of characteristics corresponds with a mechanism that is actually not a cause of the tumor of interest. Examples of the magnitude of bias that can be introduced in these situations are provided. Although categorization of tumors into homogenous subtypes may have important implications for aetiological research and identification of risk factors, the characteristics used to classify tumors into subtypes should be as close as possible to the actual pathogenic mechanisms to avoid interpretative biases. Whenever our knowledge of these mechanisms is limited, research into risk factors for tumor subtypes should first aim to causally link the characteristics to the pathogenic mechanisms

    Nutrition and Rheumatoid Arthritis Onset: A Prospective Analysis Using the UK Biobank

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    Rheumatoid arthritis (RA) is a chronic inflammatory disease that affects the joints. The multifactorial etiopathogenesis of RA has been heavily investigated, but is still only partially understood. Diet can represent both a risk factor and a protective factor, based on some evidence that suggests specific properties of certain foods and their ability to increase/reduce inflammation. To date, the studies done on this topic provide discordant results and are heterogeneous in terms of design and cohort size. In this work, we investigated for the first time the relationship between nutrition and the risk of RA onset using a sample size of about half a million subjects from one of the largest publicly available biobanks that is the UK biobank. Results showed that oily fish, alcohol, coffee and breakfast cereals have protective roles in RA; whereas, tea can increase the risk of RA. In conclusion, the obtained results confirm that diet plays key roles in RA, either by promoting or by preventing RA onset and development. Future research should focus on unravelling the effects of dietary habits on immune-mediated diseases to establish better preventive strategies

    Mental health services utilization after Mariana dam burst

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    Abstract Background The global burden of mental health conditions is increasing, especially in middle- and low-income countries and frequently the quality of mental health services is lower than the quality of services for other conditions. Disasters may increase this burden through their direct impact or due to secondary stressors, such as the preclusion of access to essential services. The aim of this study is to assess the impact of Mariana dam burst (Brazil) in November 2015, in the utilization of public mental health services by the population that experienced an interruption of water supply after the event. Methods We used data from DATASUS, the database of the Brazilian public health system, analyzing data from 34 months before to 36 months after the event. We defined as affected the population living in the municipalities of Minas Gerais state that had an interruption of water supply after the event and the rest of the state population as the comparison group. We designed an Interrupted time-series analysis to evaluate both immediate and gradual changes in use of mental health services after the accident. Results The affected population included 381,749 inhabitants and the comparison group 20,487,352 inhabitants. The monthly rate of mental health visits in the affected population in the beginning of the series was 296 (CI 182 to 409, p < 0.001) per 100.000 person-month. Comparing the groups after the event, we observed a non-statistically significant higher increase in the rate of visits immediately after the event of 115.96 (CI -30.00 to 261.92, p = 0.118) and a significant increase in the monthly rate of visits (change in slope) of 15.55 (CI 8.19 to 22.92, p < 0.001) in the affected group. Discussion The results suggest that the event translated in a long-term increase in mental health services utilization. We believe that this study presents an innovative methodology on the assessment of mental health services after disasters and that it could be adapted to other contexts. Key messages Indirect impacts of disasters may be associated with long-term changes in the utilization of mental health services. Interrupted time series using routine data are useful tools for the assessment of health services utilization following disasters

    Targeting CD20 in the treatment of interstitial lung diseases related to connective tissue diseases: A systematic review

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    INTRODUCTION: The effectiveness of CD20 targeting in connective tissue diseases (CTD) with lung involvement is controversial. This paper aims to review the current evidence about rituximab (RTX) use in CTD-related interstitial lung disease (ILD). METHODS: We performed a systematic review of papers published between January 2009 and May 2019. We included clinical trials, case/control studies and cohort studies. We excluded letters, case reports, case series, reviews, and full articles when not in English. The selected studies listed as primary or secondary outcome a variation in pulmonary function tests or in the scores used to radiologically stage lung involvement, in CTD-related ILD patients after RTX. RESULTS: Out of 1206 potentially eligible articles, 24 papers were selected: 3 retrospectively described cohorts of patients with different CTD, 14 dealt with systemic sclerosis (SSc)-related ILD, 5 with idiopathic inflammatory myopathies (IIMs)-related ILD, and 2 with Sjögren's Syndrome-related ILD. A direct comparison of the selected studies was hampered by their heterogeneity for outcomes, follow-up duration, the severity of lung involvement, and clinical features of study populations. However, an overall agreement existed concerning the effectiveness of RTX in the stabilization of lung disease, with some studies reporting an improvement of functional parameters from baseline. IIM-related ILD appeared more responsive than other CTD-related ILD to CD20 targeting. CONCLUSION: RTX is a promising therapeutic tool in CTD-related ILD. This systematic review remarks the unmet need of multicenter prospective studies aiming to evaluate the effectiveness of RTX with adequate sample size and study design

    Vitamin D as a Biomarker of Ill Health among the Over-50s: A Systematic Review of Cohort Studies.

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    BACKGROUND: The association between circulating levels of vitamin D and the incidence of chronic diseases is known. The identification of vitamin D as a biomarker of physiological/pathological ageing could contribute to expanding current knowledge of its involvement in healthy ageing. METHODS: According to PRISMA guidelines, a systematic review was conducted on cohorts studying the role of 25OH-Vitamin D [25(OH)D] and 1,25(OH)2-Vitamin D [1,25(OH)2D] concentrations as biomarkers of healthy ageing. We consulted MedLine, Scopus, and Web of Science to search for studies on the association between vitamin D status in populations of originally healthy adults, and outcomes of longevity, illness, and physical and cognitive functionality. The quality of the studies was assessed using the Newcastle Ottawa scale. RESULTS: Twenty cohorts from 24 articles were selected for this review. Inverse associations were found between low 25(OH)D levels and all-cause mortality, respiratory and cardiovascular events, as well as markers relating to hip and non-vertebral fractures. Associations between 1,25(OH)2D and healthy ageing outcomes gave similar results, although of lower clinical significance. CONCLUSIONS: This systematic review pinpoints peculiar aspects of vitamin D as a multidimensional predictor of ill health in the ageing process. Further well-designed controlled trials to investigate whether vitamin D supplement results in superior outcomes are warranted in the future

    Time-Trends of Drug-Drug Interactions among Elderly Outpatients in the Piedmont Region (Italy): A Population-Based Study

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    Adverse drug reactions (ADRs) are a major health problem in the primary care setting, particularly among the elderly population. While the high frequency of ADRs in the elderly has several causes, a major and common determinant is polypharmacy, which can in turn increase the risk of drug-drug interactions (DDIs). In this paper, we analyzed the drugs prescriptions dispensed to elderly outpatients, to assess changes in the prevalence of selected DDIs in the period 2013–2019. Overall, about 15% of the patients aged >65 years were poly-treated. Among them, a decreasing trend in prevalence was observed for the majority of DDIs during the study period. This trend was particularly noticeable for DDIs involving fluoroquinolones and vitamin K antagonists, where a sharp reduction of over 40% was observed. On the opposite, a small increase in prevalence was observed for the association of antidiabetics and beta-blocking agents and for that of clopidogrel and PPIs. While the occurrence of most of the considered DDIs among poly-treated elderly decreased over time, the prevalence of some of them is still worrying. The complexity of the national drug formularies, as well as the increased number of prescribing actors that are involved, further urges the update of DDI lists to be used to monitor drug appropriateness and reduce avoidable ADRs
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