In vascular dementia (VaD) and Alzheimer’s disease (AD), cerebral hypoperfusion and blood‐brain barrier (BBB) leakiness contribute to brain damage. In this study, we have measured biochemical markers and mediators of cerebral hypoperfusion and BBB in the frontal (BA6) and parietal (BA7) cortex and underlying white matter, to investigate the pathophysiology of vascular dysfunction in AD, VaD and mixed dementia. The ratio of myelin‐associated glycoprotein to proteolipid protein‐1 (MAG:PLP1), a post‐mortem biochemical indicator of the adequacy of ante‐mortem cerebral perfusion; the concentration of fibrinogen adjusted for haemoglobin level, a marker of blood‐brain barrier (BBB) leakiness; the level of vascular endothelial growth factor‐A (VEGF), a marker of tissue hypoxia; and endothelin‐1 (EDN1), a potent vasoconstrictor, were measured by ELISA in the frontal and parietal cortex and underlying white matter in 94 AD, 20 VaD, 33 mixed dementia cases and 58 age‐matched controls. All cases were assessed neuropathologically for small vessel disease (SVD), cerebral amyloid angiopathy (CAA) severity, Aβ and phospho‐tau parenchymal load, and Braak tangle stage. Aβ40 and Aβ42 were measured by ELISA in guanidine‐HCl tissue extracts. We found biochemical evidence of cerebral hypoperfusion in AD, VaD and mixed dementia to be associated with SVD, Aβ level, plaque load, EDN1 level and Braak tangle stage, and to be most widespread in mixed dementia. There was evidence of BBB leakiness in AD—limited to the cerebral cortex and related to EDN1 level. In conclusion, abnormalities of cerebral perfusion and BBB function in common types of dementia can largely be explained by a combination of arteriolosclerosis, and Aβ‐, tau‐ and endothelin‐related vascular dysfunction. The relative contributions of these processes vary considerably both between and within the diseases.
This study examines the trends in reference evapotranspiration (ET o ) in Turkey by analysing data from 77 weather stations for a 32-year period . ET o values were calculated using the Penman-Monteith method using air temperature, wind speed, relative humidity, and sunshine hours data. Trends in annual and monthly ET o were determined using the Mann-Kendall trend test with the trend-free prewhitening procedure. The magnitude of trends was estimated by calculating the Sen's slope. The collective or field significance of the trends was evaluated using Walker test. The possible causes of changes in ET o were discussed by analysing the trends in air temperature, wind speed, relative humidity, and solar radiation data collected at the same stations. The implications of ET o trends for crop water requirements were evaluated. The analyses showed that the majority of stations (88%) in Turkey had annual ET o between 750 and 1200 mm during the 32-year period and ET o decreased gradually from south to north. From 1975 to 2006, 58% of stations had upward trends in annual ET o . Upward trends were statistically significant at the 0.05 level for 32% of stations. The rates of changes in annual ET o were on average 1.20 mm year −2 . The trends detected in monthly ET o were mostly upward with an average magnitude between −0.01 and 0.14 mm month year −1 . Trends detected at the annual timescale and for the majority of the months provided the field significance at the 0.05 level. Analysis of other climatic data showed that upward trends in air temperatures, downward trends in wind speeds, and downward trends in relative humidity were widespread over Turkey for the same time period. Changes in these three parameters could explain the majority of the changes in ET o rates. The ET o changes affect crop water requirements and increase the demand for irrigation.
This cross-sectional study aimed to evaluate depression and anxiety symptoms of the children/grandchildren of COVID-19 patients, children/grandchildren of healthcare workers who have not infected COVID-19, and children/grandchildren of the control group. Parent and children’s perception about COVID-19–related stigma is also investigated and compared between groups. The perception about COVID-19–related stigma between different age and gender groups among children also investigated and compared. The mental health of the 71 participants aged 6–18 years was evaluated via a telemedicine-based semi-structured interview between March and April 2020. Children’s Depression Inventory (CDI), the Screen for Child Anxiety-Related Emotional Disorders (SCARED), and COVID-19–Related Stigma Form were administered to the participants. A significant negative correlation was found between age and separation anxiety disorder ( p = .005) and a significant positive correlation was found between age and generalized anxiety disorder ( p = .035) in the SCARED-Child report. Generalized anxiety disorder was found to be higher in females compared to males. A significant difference was found between the groups of parents in the COVID-19–Related Stigma Form. Patients infected with COVID-19, healthcare workers, and the control group have different perceptions about COVID-19–related stigma. The age of the children have an impact on stigma perceptions. Anxiety symptoms of children affected by age and gender. Future studies are recommended to determine the other factors associated with perceptions about COVID-19–related stigma among children and parents.
A new, modern graphical user interface (GUI) for the 2015 version of the Wilson-Devinney (WD) code is developed. PyWD2015 is written in P ython 2.7 and uses the Qt4 interface framework. At its core, the GUI generates lcin and dcin files from user inputs and sends them to WD, then reads and visualises the output in a user friendly way. It also includes some useful tools for the user, which makes technical aspects of the modelling process significantly easier. While multiple sky surveys and space missions generate, reduce and categorize large amounts of observational data, it's up to dedicated studies to analyse peculiar or anomalous systems and make further progress in the field of physics of eclipsing binaries. We believe PyWD2015 will be a great "dedicated study" suite for such systems.
Hypertension in midlife contributes to cognitive decline and is a modifiable risk factor for dementia. The relationship between late-life hypertension and dementia is less clear. We have investigated the relationship of blood pressure and hypertensive status during later life (after 65 y) to post-mortem markers of Alzheimer's disease (amyloid-β and tau loads), arteriolosclerosis and cerebral amyloid angiopathy; and to biochemical measures of ante-mortem cerebral oxygenation (the myelin-associated glycoprotein:proteolipid protein-1 ratio, which is reduced in chronically hypoperfused brain tissue, and the level of vascular endothelial growth factor-A, which is upregulated by tissue hypoxia), blood-brain barrier damage (indicated by an increase in parenchymal fibrinogen), and pericyte content (platelet-derived growth factor receptor β which declines with pericyte loss) in Alzheimer's disease (n = 75), vascular (n = 20), and mixed dementia (n = 31) cohorts. Systolic and diastolic blood pressure measurements were obtained retrospectively from clinical records. Non-amyloid small vessel disease and cerebral amyloid angiopathy were scored semi-quantitatively. Amyloid-β and tau loads were assessed by field fraction measurement in immunolabelled sections of frontal and parietal lobes. Homogenates of frozen tissue from the contralateral frontal and parietal lobes (cortex and white matter) were used to measure markers of vascular function by enzyme-linked immunosorbent assay. Diastolic (but not systolic) blood pressure was associated with preservation of cerebral oxygenation, correlating positively with the ratio of myelin-associated glycoprotein to proteolipid protein-1 and negatively with vascular endothelial growth factor-A in both frontal and parietal cortex. Diastolic blood pressure correlated negatively with parenchymal amyloid-β in the parietal cortex. In dementia cases, elevated late-life diastolic blood pressure was associated with more severe arteriolosclerosis and cerebral amyloid angiopathy, and diastolic blood pressure correlated positively with parenchymal fibrinogen, indicating blood-brain barrier breakdown, in both regions of cortex. Systolic blood pressure was related to lower platelet-derived growth factor receptor β in controls in the frontal cortex, and in dementia cases in the superficial white matter. We found no association between blood pressure and tau. Our findings demonstrate a complex relationship between late-life blood pressure, disease pathology, and vascular function in dementia. We suggest that hypertension helps to reduce cerebral ischaemia (and may slow β-amyloid accumulation) in the face of increasing cerebral vascular resistance, but exacerbates vascular pathology.
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