1,720,972 research outputs found
Cerebrovascular Disease Related to Hypertension: Effects of Antioxidant and Cholinergic Precursor Molecules
No full textBackground. A major risk factor for cerebral vascular disease and cognitive impairment is
hypertension. Increased arterial wall thickness and elevated blood pressure cause hypertension.
Moreover, many studies have shown that cerebrovascular alterations may cause disease in
hypertensive individuals' brains because of an increase in reactive oxygen species,
neuroinflammation, and cholinergic dysfunction. The effects of hypertension on the brain lead to
cognitive decline and dementia. Increasing reactive oxygen species and impairment of cholinergic
pathways are the mechanisms of hypertension-induced cerebrovascular alterations. In
spontaneously hypertensive rats as a model of essential hypertension and brain injury, neural
alterations, blood-brain barrier dysfunction, and gliosis were observed.
Aim. The study aimed to determine whether choline alphoscerate (GPC) and (+) thioctic acid [(+)
TIO], either alone or in combination, were investigated for their potential neuroprotective
properties. GPC is a choline-containing phospholipid known for its ability to enhance cholinergic
neurotransmission. The (+) TIO eutomer has been shown to exhibit greater antioxidant and anti-
inflammatory activity than its racemic counterpart.
Methods. Hypertensive rats aged 24 weeks were treated with GPC and (+) TIO individually or in
combination. Normotensive age matched Wistar Kyoto rats were used as control. To study the
oxidative status, 4-hydroxynonenal (4-HNE) concentration, protein oxidation was measured in the
brain sample. For the assessment of the inflammatory process, the frontal cortex and the
hippocampus were collected for western blot and immunohistochemistry investigations of glial,
BBB and neuroinflammatory and the cholinergic markers.
Results. In hypertensive rats, the blood pressure was higher than in normotensive ones. After four
weeks of treatment with GPC and (+) TIO, slight reductions in systolic blood pressure were
observed. OxyBlot in the brain showed an increase of oxidative state proteins in SHR. Based on
Western blot and immunohistochemistry studies, GPC alone was able to restore the protein levels
in neuronal nuclei. There was no difference between the two compounds regarding the
downregulation of synaptic proteins in hypertensive rats. However, GPC and (+) TIO alone or in
combination reduced astrogliosis, microglial activation, and decreased levels of the
proinflammatory cytokine tumor necrosis factor alpha. It was observed that treatments partially
restored the modulation of the blood-brain barrier markers aquaporin-4 and glucose transporter-1
in hypertensive rats. Because of the cholinergic neurotransmission mechanism of GPC, it was able
to increase the expression level of vesicular acetylcholine transporter in brain areas of SHR. The
increase expression of nAChRα7 with the GPC and the GPC and (+) TIO may suggest a protective
effect mediated by the cholinergic anti-inflammatory pathway.
Conclusion. Our findings can contribute to better defining the role of the inflammatory processes
of neurovascular unit in brain disorders characterized by vascular impairment. Based on the
evidence, treatment with GPC alone and GPC plus (+)TIO attenuates the glial reaction and the
neuroinflammation in the two brain areas, providing neuroprotection by the stimulation of the
cholinergic pathways. Furthermore, that may be a therapeutic strategy worth exploring in further
preclinical and clinical research
Effects of choline containing phospholipids on the neurovascular unit: A review
No full textThe roles of choline and of choline-containing phospholipids (CCPLs) on the maintenance and progress of neurovascular unit (NVU) integrity are analyzed. NVU is composed of neurons, glial and vascular cells ensuring the correct homeostasis of the blood-brain barrier (BBB) and indirectly the function of the central nervous system. The CCPLs phosphatidylcholine (lecithin), cytidine 5′-diphosphocholine (CDP-choline), choline alphoscerate or α-glyceryl-phosphorylcholine (α-GPC) contribute to the modulation of the physiology of the NVU cells. A loss of CCPLs contributes to the development of neurodegenerative diseases such as Alzheimer’s disease, multiple sclerosis, Parkinson’s disease. Our study has characterized the cellular components of the NVU and has reviewed the effect of lecithin, of CDP-choline and α-GPC documented in preclinical studies and in limited clinical trials on these compounds. The interesting results obtained with some CCPLs, in particular with α-GPC, probably would justify reconsideration of the most promising molecules in larger attentively controlled studies. This can also contribute to better define the role of the NVU in the pathophysiology of brain disorders characterized by vascular impairment
Altered Brain Cholinergic and Synaptic Markers in Obese Zucker Rats
No full textThe association between obesity and loss of cognitive performance has been recognized. Although there are data regarding the metabolic alterations in obese conditions and the development of neuroinflammation, no clear evidence concerning obesity-related cholinergic and synaptic impairments in the frontal cortex and hippocampus has been reported yet. Here, we investigate different cholinergic and synaptic markers in 12-, 16-, and 20-week-old obese Zucker rats (OZRs) compared with lean littermate rats (LZRs), using immunochemical and immunohistochemical analysis. Consequently, OZRs showed body weight gain, hypertension, and dysmetabolism. In 20-week-old OZRs, the reduction of vesicular acetylcholine transporter (VAChT) and alpha7 nicotinic acetylcholine receptors (α7nAChR) occurred both in the frontal cortex and in the hippocampus, suggesting a cognitive dysfunction due to obesity and aging. Among the muscarinic receptors analyzed, the level of expression of type 1 (mAChR1) was lower in the hippocampus of the older OZRs. Finally, we showed synaptic dysfunctions in OZRs, with a reduction of synaptophysin (SYP) and synaptic vesicle glycoprotein 2B (SV2B) in 20-week-old OZRs, both in the frontal cortex and in the hippocampus. Taken together, our data suggest specific alterations of cholinergic and synaptic markers that can be targeted to prevent cognitive deficits related to obesity and aging
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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