共查询到20条相似文献,搜索用时 31 毫秒
1.
Carme Gubern Olivia Hurtado Rocío Rodríguez Jesús R Morales Víctor G Romera María A Moro Ignacio Lizasoain Joaquín Serena Judith Mallolas 《BMC molecular biology》2009,10(1):57
Background
Studies of gene expression in experimental cerebral ischaemia models can contribute to understanding the pathophysiology of brain ischaemia and to identifying prognostic markers and potential therapeutic targets. The normalization of relative qRT-PCR data using a suitable reference gene is a crucial prerequisite for obtaining reliable conclusions. No validated housekeeping genes have been reported for the relative quantification of the mRNA expression profile activated in in-vitro ischaemic conditions, whereas for the in-vivo model different reference genes have been used. 相似文献2.
Background
The Circle of Willis (CoW) is the most important collateral pathway of the cerebral artery. The present study aims to investigate the collateral capacity of CoW with anatomical variation when unilateral internalcarotid artery (ICA) is occluded.Methods
Basing on MRI data, we have reconstructed eight 3D models with variations in the posterior circulation of the CoW and set four different degrees of stenosis in the right ICA, namely 24%, 43%, 64% and 79%, respectively. Finally, a total of 40 models are performed with computational fluid dynamics simulations. All of the simulations share the same boundary condition with static pressure and the volume flow rate (VFR) are obtained to evaluate their collateral capacity.Results
As for the middle cerebral artery (MCA) and the anterior cerebral artery (ACA), the transitional-type model possesses the best collateral capacity. But for the posterior cerebral artery (PCA), unilateral stenosis of ICA has the weakest influence on the unilateral posterior communicating artery (PCoA) absent model. We also find that the full fetal-type posterior circle of Willis is an utmost dangerous variation which must be paid more attention.Conclusion
The results demonstrate that different models have different collateral capacities in coping stenosis of unilateral ICA and these differences can be reflected by different outlets. The study could be used as a reference for neurosurgeon in choosing the best treatment strategy.3.
Biotic interactions influence the projected distribution of a specialist mammal under climate change
Brooke L. Bateman Jeremy VanDerWal Stephen E. Williams Christopher N. Johnson 《Diversity & distributions》2012,18(9):861-872
Aim
To measure the effects of including biotic interactions on climate‐based species distribution models (SDMs) used to predict distribution shifts under climate change. We evaluated the performance of distribution models for an endangered marsupial, the northern bettong (Bettongia tropica), comparing models that used only climate variables with models that also took into account biotic interactions.Location
North‐east Queensland, Australia.Methods
We developed separate climate‐based distribution models for the northern bettong, its two main resources and a competitor species. We then constructed models for the northern bettong by including climate suitability estimates for the resources and competitor as additional predictor variables to make climate + resource and climate + resource + competition models. We projected these models onto seven future climate scenarios and compared predictions of northern bettong distribution made by these differently structured models, using a ‘global’ metric, the I similarity statistic, to measure overlap in distribution and a ‘local’ metric to identify where predictions differed significantly.Results
Inclusion of food resource biotic interactions improved model performance. Over moderate climate changes, up to 3.0 °C of warming, the climate‐only model for the northern bettong gave similar predictions of distribution to the more complex models including interactions, with differences only at the margins of predicted distributions. For climate changes beyond 3.0 °C, model predictions diverged significantly. The interactive model predicted less contraction of distribution than the simpler climate‐only model.Main conclusions
Distribution models that account for interactions with other species, in particular direct resources, improve model predictions in the present‐day climate. For larger climate changes, shifts in distribution of interacting species cause predictions of interactive models to diverge from climate‐only models. Incorporating interactions with other species in SDMs may be needed for long‐term prediction of changes in distribution of species under climate change, particularly for specialized species strongly dependent on a small number of biotic interactions. 相似文献4.
Bin Zhang Cong Gao Ning Yang WeiZhi Zhang XingWang Song JianRui Yin ShuXiang Pu YongHong Yi QingChun Gao 《BMC neurology》2010,10(1):82
Background
Elevated serum uric acid (SUA) levels can enhance its antioxidant prosperities and reduce the occurrence of cerebral infarction. Significantly elevated SUA levels have been associated with a better prognosis in patients with cerebral infarction; however, the results from some studies on the relationship between SUA and the prognosis of patients with cerebral infarction remain controversial. 相似文献5.
Behzad Eftekhar Majid Dadmehr Saeed Ansari Mohammad Ghodsi Bashir Nazparvar Ebrahim Ketabchi 《BMC neurology》2006,6(1):22
Background
Previous studies have proposed correlation between variants of the cerebral arterial circle (also known as circle of Willis) and some cerebrovascular diseases. Differences in the incidence of these diseases in different populations have also been investigated. The study of variations in the anatomy of the cerebral arterial circle may partially explain differences in the incidence of some of the cerebrovascular diseases in different ethnic or racial groups. 相似文献6.
Denis Perko Janja Pretnar-Oblak Mišo Šabovič Marjan Zaletel Bojana Žvan 《BMC neurology》2011,11(1):146
Background
There is a growing interest in the role of the endothelium in migraine. Recently, our group showed differences in endothelial function between the anterior and posterior cerebral circulation in healthy subjects, reduced vasodilatatory capacity of the posterior cerebral circulation and unimpaired systemic endothelial function in migraine patients without comorbidities. However, the relationship between cerebral and systemic endothelial function and the anterior and posterior cerebral endothelial function in migraine patients is still not clear. 相似文献7.
Long-term prognosis of symptomatic isolated middle cerebral artery disease in Korean stroke patients
Mi Sun Oh Kyung-Ho Yu Min-Kyung Chu Hyeo-Il Ma Yun Joong Kim Joo Yong Kim Byung-Chul Lee 《BMC neurology》2011,11(1):138
Background
This study aimed to investigate the long-term mortality and recurrence rate of stroke in first-time stroke patients with symptomatic isolated middle cerebral artery disease (MCAD) under medical management. 相似文献8.
Peder E Bilde Mette Kliim-Due Betina Rasmussen Line Z Petersen Tue H Petersen Jens B Nielsen 《BMC neurology》2011,11(1):32
Background
The available health resources limit the amount of therapy that may be offered to children with cerebral palsy and the amount of training in each session may be insufficient to drive the neuroplastic changes, which are necessary for functional improvements to take place. The aim of this pilot study was to provide proof of concept that individualized and supervised interactive home-based training delivered through the internet may provide an efficient way of maintaining intensive training of children with cerebral palsy over prolonged periods. 相似文献9.
Adviye Ergul Mostafa M Elgebaly Mary-Louise Middlemore Weiguo Li Hazem Elewa Jeffrey A Switzer Christiana Hall Anna Kozak Susan C Fagan 《BMC neurology》2007,7(1):33
Background
Interruption of flow through of cerebral blood vessels results in acute ischemic stroke. Subsequent breakdown of the blood brain barrier increases cerebral injury by the development of vasogenic edema and secondary hemorrhage known as hemorrhagic transformation (HT). Diabetes is a risk factor for stroke as well as poor outcome of stroke. The current study tested the hypothesis that diabetes-induced changes in the cerebral vasculature increase the risk of HT and augment ischemic injury. 相似文献10.
Background
Dynamic cerebral autoregulation after intracerebral hemorrhage (ICH) remains poorly understood. We performed a case-control study to compare dynamic autoregulation between ICH patients and healthy controls. 相似文献11.
Chie Usui Kotaro Hatta Nagafumi Doi Atsushi Nakanishi Hiroyuki Nakamura Kusuki Nishioka Heii Arai 《Arthritis research & therapy》2010,12(2):R64
Introduction
The aim of the present study was to determine the brain areas associated with fibromyalgia, and whether pretreatment regional cerebral blood flow (rCBF) can predict response to gabapentin treatment. 相似文献12.
Armin Schneider Rainer Wysocki Claudia Pitzer Carola Krüger Rico Laage Stefan Schwab Alfred Bach Wolf-Rüdiger Schäbitz 《BMC biology》2006,4(1):36-8
Background
Granulocyte-colony stimulating factor (G-CSF) is known as a powerful regulator of white blood cell proliferation and differentiation in mammals. We, and others, have shown that G-CSF is effective in treating cerebral ischemia in rodents, both relating to infarct size as well as functional recovery. G-CSF and its receptor are expressed by neurons, and G-CSF regulates apoptosis and neurogenesis, providing a rational basis for its beneficial short- and long-term actions in ischemia. In addition, G-CSF may contribute to re-endothelialisation and arteriogenesis in the vasculature of the ischemic penumbra. In addition to these trophic effects, G-CSF is a potent neuroprotective factor reliably reducing infarct size in different stroke models. 相似文献13.
Background
Inflammatory reactions occurring in the brain after ischemia may contribute to secondary damage. In the present study, effects of minocycline, an anti-inflammatory agent, alone or in combination with mild hypothermia on focal embolic cerebral ischemia have been examined. 相似文献14.
Background
Holmes tremor is a rare symptomatic movement disorder. Currently suggested pathophysiological mechanisms of the disease are mostly derived from stroke cases. Although rare, cerebral toxoplasmosis may strengthen the pathophysiologic mechanism of disease. 相似文献15.
Claudia Trappetti Luciana Gualdi Lorenzo Di Meola Prashant Jain Cindy C Korir Paul Edmonds Francesco Iannelli Susanna Ricci Gianni Pozzi Marco R Oggioni 《BMC microbiology》2011,11(1):75
Background
Different models for biofilm in Streptococcus pneumoniae have been described in literature. To permit comparison of experimental data, we characterised the impact of the pneumococcal quorum-sensing competence system on biofilm formation in three models. For this scope, we used two microtiter and one continuous culture biofilm system. 相似文献16.
Adam J. Wells Robert Vink Stephen C. Helps Steven J. Knox Peter C. Blumbergs Renée J. Turner 《PloS one》2015,10(6)
Introduction
Malignant middle cerebral artery (MCA) stroke has a disproportionately high mortality due to the rapid development of refractory space-occupying cerebral edema. Animal models are essential in developing successful anti-edema therapies; however to date poor clinical translation has been associated with the predominately used rodent models. As such, large animal gyrencephalic models of stroke are urgently needed. The aim of the study was to characterize the intracranial pressure (ICP) response to MCA occlusion in our recently developed ovine stroke model.Materials and Methods
30 adult female Merino sheep (n = 8–12/gp) were randomized to sham surgery, temporary or permanent proximal MCA occlusion. ICP and brain tissue oxygen were monitored for 24 hours under general anesthesia. MRI, infarct volume with triphenyltetrazolium chloride (TTC) staining and histology were performed.Results
No increase in ICP, radiological evidence of ischemia within the MCA territory but without space-occupying edema, and TTC infarct volumes of 7.9+/-5.1% were seen with temporary MCAO. Permanent MCAO resulted in significantly elevated ICP, accompanied by 30% mortality, radiological evidence of space-occupying cerebral edema and TTC infarct volumes of 27.4+/-6.4%.Conclusions
Permanent proximal MCAO in the sheep results in space-occupying cerebral edema, raised ICP and mortality similar to human malignant MCA stroke. This animal model may prove useful for pre-clinical testing of anti-edema therapies that have shown promise in rodent studies. 相似文献17.
Han-Hsin Chang Bo-Yie Chen Chia-Yung Wu Zih-Jay Tsao Ying-Yu Chen Chin-Pao Chang Chi-Rei Yang David Pei-Cheng Lin 《Journal of biomedical science》2011,18(1):6
Background
Hedgehog signalling has been implicated in prostate tumorigenesis in human subjects and mouse models, but its effects on transforming normal basal/stem cells toward malignant cancer stem cells remain poorly understood. 相似文献18.
Background
Correlation between the expression levels of genes which are located close to each other on the genome has been found in various organisms, including yeast, drosophila and humans. Since such a correlation could be explained by several biochemical, evolutionary, genetic and technological factors, there is a need for statistical models that correspond to specific biological models for the correlation structure. 相似文献19.
Sefanja Achterberg L. Jaap Kappelle Paul I. W. de Bakker Matthew Traylor Ale Algra SMART Study Group the METASTROKE Consortium 《PloS one》2015,10(4)
Background
Patients who have suffered from cerebral ischemia have a high risk of recurrent vascular events. Predictive models based on classical risk factors typically have limited prognostic value. Given that cerebral ischemia has a heritable component, genetic information might improve performance of these risk models. Our aim was to develop and compare two models: one containing traditional vascular risk factors, the other also including genetic information.Methods and Results
We studied 1020 patients with cerebral ischemia and genotyped them with the Illumina Immunochip. Median follow-up time was 6.5 years; the annual incidence of new ischemic events (primary outcome, n=198) was 3.0%. The prognostic model based on classical vascular risk factors had an area under the receiver operating characteristics curve (AUC-ROC) of 0.65 (95% confidence interval 0.61-0.69). When we added a genetic risk score based on prioritized SNPs from a genome-wide association study of ischemic stroke (using summary statistics from the METASTROKE study which included 12389 cases and 62004 controls), the AUC-ROC remained the same. Similar results were found for the secondary outcome ischemic stroke.Conclusions
We found no additional value of genetic information in a prognostic model for the risk of ischemic events in patients with cerebral ischemia of arterial origin. This is consistent with a complex, polygenic architecture, where many genes of weak effect likely act in concert to influence the heritable risk of an individual to develop (recurrent) vascular events. At present, genetic information cannot help clinicians to distinguish patients at high risk for recurrent vascular events. 相似文献20.