65 research outputs found

    Isentropic Analysis of Convective Motions

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    This paper analyzes the convective mass transport by sorting air parcels in terms of their equivalent potential temperature to determine an isentropic streamfunction. By averaging the vertical mass flux at a constant value of the equivalent potential temperature, one can compute an isentropic mass transport that filters out reversible oscillatory motions such as gravity waves. This novel approach emphasizes the fact that the vertical energy and entropy transports by convection are due to the combination of ascending air parcels with high energy and entropy and subsiding air parcels with lower energy and entropy. Such conditional averaging can be extended to other dynamic and thermodynamic variables such as vertical velocity, temperature, or relative humidity to obtain a comprehensive description of convective motions. It is also shown how this approach can be used to determine the mean diabatic tendencies from the three-dimensional dynamic and thermodynamic fields. A two-stream approximation that partitions the isentropic circulation into a mean updraft and a mean downdraft is also introduced. This offers a straightforward way to identify the mean properties of rising and subsiding air parcels. The results from the two-stream approximation are compared with two other definitions of the cloud mass flux. It is argued that the isentropic analysis offers a robust definition of the convective mass transport that is not tainted by the need to arbitrarily distinguish between convection and its environment, and that separates the irreversible convective overturning fromoscillations associated with gravity waves

    What determines spontaneous physical activity in patients with parkinsons disease?

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    Physical activity (PA) is a factor that may have an influence on the symptoms of Parkinson’s disease (PD). The aim of this study was to identify the potential determinants of spontaneous PA in a PD patient group. A total of 134 PD patients aged 65.2 ± 9.2 years with a Hoehn–Yahr scale score ≤4 and a Mini Mental State Examination (MMSE) score ≥24 were examined. For the study’s purposes, the authors analyzed age, sex, education, history of PD, dopaminergic treatment, the severity of PD symptoms using Unified Parkinson’s Disease Rating Scale (UPDRS), and Hoehn–Yahr scale. Additionally, all participants were evaluated through a set of scales for specific neuropsychiatric symptoms including depression, anxiety, apathy, fatigue, and sleep disorders. A linear regression analysis was used with backward elimination. In the total explanatory model, for 12% of the variability in activity (R2 = 0.125; F(16.133) = 2.185; p < 0.01), the significant predictor was starting therapy with the dopamine agonist (DA) (β= 0.420; t= 4.068; p = 0.000), which was associated with a longer duration of moderate PA. In the total explanatory model, for more than 13% of the variance in time spent sitting (R2 = 0.135; F(16.130) = 2.267; p < 0.01), the significant predictors were secondary education and the results of the UPDRS. The patients with secondary and vocational education, those starting treatment with DA and those with a less severe degree of Parkinson’s symptoms (UPDRS), spent less time sitting in a day. It is possible to identify determinants of spontaneous PA. It may elucidate consequences in terms of influence on modifiable conditions of PA and the proper approach to patients with unmodifiable PA factors

    The sustained increase of plasma fibrinogen during ischemic stroke predicts worse outcome independently of baseline fibrinogen level

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    Hyperfibrinogenemia at the beginning of ischemic stroke is associated with poor outcome. We hypothesized that the sustained increase of plasma fibrinogen during stroke predicts outcome independently of baseline fibrinogen concentration. We included 266 patients with first-ever ischemic stroke in whom plasma fibrinogen level was measured on days 1, 7, and 14. The sustained fibrinogen's increase was defined as the persistent elevation of fibrinogen's concentration on days 7 and 14 by at least 20 % compared to the level on day 1. The functional outcome on day 30 was assessed using modified Rankin Scale (mRS). Favorable outcome was defined as mRS 0-1. The sustained increase of fibrinogen was found in 17 % of patients. On multivariate logistic regression analysis adjusted for age, NIHSS score, baseline fibrinogen >2.66 mmol/L, presence of infection, and hyperglycemia, the sustained fibrinogen's level was associated with reduced chance of favorable outcome (OR: 0.17, 95 % CI: 0.06-0.48, P<0.01)

    Lack of association of CR1, PICALM and CLU gene polymorphisms with Alzheimer disease in a Polish population

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    Background and purpose: Recent genome-wide association studies have indicated 3 new susceptibility loci for Alzheimer disease (AD): complement receptor 1 (CR1), clusterin (CLU), and the phosphatidylinositol-binding clathrin assembly protein (PICALM). We investigated the influence of the rs6656401 single nucleotide polymorphisms (SNP) of the CR1 gene, the rs3851179 SNP of the PICALM gene, and the rs11136000 SNP of the CLU gene on risk of AD in a Polish population. Material and methods: In 253 Caucasian AD patients and 240 controls, analyses identifying the rs6656401, rs3851179 and rs11136000 SNPs and APOE common polymorphisms were performed. Results: No significant differences were observed in the distribution of the rs6656401 of CR1, rs3851179 of PICALM and rs11136000 of CLU SNPs between AD patients and controls. The APOE ε4 common polymorphism was strongly related to the risk of AD. Conclusion: Our results suggest that investigated SNPs are not associated with AD in a Polish population

    Improvement of survival in Polish stroke patients is related to reduced stroke severity and better control of risk factors : the Krakow Stroke Database

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    Introduction: In the last decade, the stroke mortality rate in Poland significantly decreased. We hypothesised that stroke severity, the major determinant of outcome, is lowered in Polish stroke patients. Material and methods: We compared the stroke severity in two cohorts of first-ever ischaemic stroke patients admitted within 24 h after stroke onset to the Department of Neurology, Jagiellonian University, Krakow in the years 1994-2000 and 2008-2012. To assess stroke severity we used the National Institute of Health Stroke Scale (NIHSS). We defined mild stroke as an NIHSS score ≤ 4. Results: We included 816 patients hospitalised in the years 1994-2000 and 569 patients hospitalised in the years 2008-2012. NIHSS score on admission was higher in the former (mean: 12.0 ±7.0 vs. 8.0 ±6.0, p < 0.01), and the frequency of mild stroke was higher in the latter (12.7% vs. 41.8%, p < 0.01). Although the frequency of hypertension (67.3% vs. 81.2%, p < 0.01), diabetes mellitus (20.8% vs. 26.4%, p = 0.02) and atrial fibrillation (20.7% vs. 26.2%, p = 0.02) was higher in patients hospitalised in the years 2008- 2012, the systolic and diastolic blood pressure values and the frequency of fasting hyperglycaemia were lower in this cohort. This cohort also less frequently suffered from hypercholesterolaemia (25.4% vs. 16.3%, p < 0.01). Conclusions: Reduced stroke severity is associated with better recognition and control of risk factors and explains the improvement of survival in Polish stroke patients

    Pre-stroke apathy symptoms are associated with an increased risk of delirium in stroke patients

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    Neuropsychiatric symptoms can be interrelated to delirium. We aimed to investigate an association between pre-stroke neuropsychiatric symptoms and the risk of delirium in stroke patients. We included 606 patients (median age: 73, 53% female) with stroke or transient ischemic attack admitted within 48 hours from symptoms onset. We assessed delirium on a daily basis during the first 7 days of hospitalization. To make diagnosis of delirium we used DSM-5 criteria. We used Neuropsychiatric Inventory to assess neuropsychiatric symptoms occurring within 4 weeks prior to stroke. We diagnosed delirium in 28.2% of patients. On univariate analysis, higher score of pre-stroke depression (OR: 1.58, 95% CI: 1.04–2.40, P = 0.03), apathy (OR: 2.23, 95% CI: 1.44–3.45, P < 0.01), delusions (OR: 2.00, 95% CI: 1.09–3.68, P = 0.03), hallucinations (OR: 2.39, 95% CI: 1.19–4.81, P = 0.01) and disinhibition (OR: 2.10, 95% CI: 1.04–4.25, P = 0.04) was associated with the increased risk of delirium. On multivariate analysis adjusted for age, atrial fibrillation, diabetes mellitus, stroke severity, right hemisphere lesion, pre-stroke cognitive decline, pre-stroke disability and infections, higher apathy score (OR: 2.03, 95% CI: 1.17–3.50, P = 0.01), but no other neuropsychiatric symptoms, remained independent predictor of delirium. We conclude that pre-stroke apathy symptoms are associated with increased risk of delirium in stroke patients

    Influence of rs1080985 single nucleotide polymorphism of the CYP2D6 gene on response to treatment with donepezil in patients with Alzheimer's disease

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    BACKGROUND: Recent data indicate that the rs1080985 single nucleotide polymorphism of the cytochrome P450 (CYP) 2D6 gene may affect the response to treatment with donepezil in patients with Alzheimer’s disease. There is also evidence that the common apolipoprotein E (APOE) polymorphism may affect the response to treatment with donepezil in Alzheimer’s disease. We investigated the association between response to donepezil and the rs1080985 single nucleotide polymorphism, the minor allele (G) of which was previously reported to be associated with a poor response to this drug in patients with Alzheimer’s disease. The common APOE polymorphism was also assessed for its relevance to the outcome of this treatment. METHODS: Analysis of CYP2D6 and APOE polymorphisms was undertaken in 88 naive Caucasian patients with Alzheimer’s disease. All patients received treatment with donepezil for at least 10 months, and the response to treatment was then assessed according to the National Institute for Health and Clinical Excellence criteria. RESULTS: No significant differences were observed in distribution of the CYP2D6 rs1080985 single nucleotide polymorphism or common APOE polymorphism between responders (68.2%) and nonresponders (31.8%) to treatment with donepezil. CONCLUSION: Our results suggest that neither the CYP2D6 nor the APOE polymorphism influences the response to treatment with donepezil in a Polish population with Alzheimer’s disease
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