Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cost of treatment of ischemic stroke (second cause of death for elderly patients) is increasing. carotid bifurcation surgery can change the prognosis (as proven by NASCET and ECST studies) for symptomatic patients with over 70% of carotid narrowing. Exploration of the carotid bifurcation is an important step in the diagnosis and must assess the degree of stenosis, the smoothness of the plaque and describe the collateral vessels. Duplex sonography is used to analyze the plaque and to measure the hemodynamic consequences beyond the stenosis. Transcranial Doppler is used to study the hemodynamic consequences at the circle of Willis. 3D TOF MR Angiography visualizes vessels using MIP but with a risk of overestimation of the degree of stenosis. A good morphological study of the circle of Willis can be achieved. With spiral CT, 3D data bases can be acquired with a single injection of contrast medium. Analysis is based on native, reformatted and MIP images. The image quality is generally good, but decreases in the case of huge calcifications. Brain examination can be performed in the same session, looking for rupture of the blood-brain barrier. Angiography remains the gold standard with a high complication rate. It allows excellent analysis from the aortic arch to distal cortical vessels. Isotope studies are only performed in difficult cases (vertebro-basilar lesions, differential diagnosis). Duplex ultrasound is performed first in all protocols. Until recently, angiography was performed before surgery, but the current tendency is to use a less invasive examination (MR angiography or CT angiography) and angiography is then only performed when necessary. A knowledge of the respective advantages of each technique is essential in order to adapt the protocols to each local team.
 ...
PMID:[Multimodal approach to carotid bifurcation in atherosclerosis]. 968 16

In the hyperacute phase of stroke, occluded vessels can be seen as high signal on fast-FLAIR images or as absence of flow-related enhancement in maximum-intensity projection (MIP) MR angiography (MRA). To compare these techniques, we examined 53 patients within 6 h of a stroke, using a standardised MRI protocol including fast-FLAIR and 3D time-of-flight TOF MR to detect vessel occlusion or reduced flow corresponding to the suspected ischaemic territory. Brain infarcts were confirmed on MRI after 1-5 days in 41 cases (77%). The overall accuracy of 3D-TOF MRA was 68% and sensitivity, specificity, positive and negative predictive values were 67%, 71%, 87%, and 43% respectively. Values for the fast-FLAIR sequence were: 65%, 85%, 93% and 44%, with an overall accuracy of 70%. The fast-FLAIR sequence was thus able to show occluded vessels or reduced flow with about the same accuracy as 3D-TOF MRA and enabled better prediction of the ischaemic area.
 ...
PMID:Fast FLAIR sequence for detecting major vascular abnormalities during the hyperacute phase of stroke: a comparison with MR angiography. 1037 91

Basilar artery thrombosis should be diagnosed immediately, as intra-arterial thrombolysis might improve the outcome. Diffusion-weighted (DWI)-MRI and three-dimensional time-of-flight MR angiography (3D TOF Turbo MRA) may provide additional insight into the extent of ischemia and the level of the occlusion. These methods could be helpful in the early classification of vertebrobasilar stroke, thus reserving the use of conventional angiography and possible intra-arterial thrombolysis for patients who had a severe clinical picture explained by preliminary assessments. We report the case of a 74-year-old woman who experienced a basilar artery occlusion; DWI-MRI and 3D TOF Turbo MRA provided noninvasive information concerning the level of arterial occlusion and its parenchymal ischemic impact, this leading to an intra-arterial thrombolytic therapy. These data suggest the feasibility of a noninvasive urgent diagnostic and prognostic approach with DWI-MRI and 3D TOF Turbo MRA in basilar occlusion.
 ...
PMID:Hyperacute diffusion-weighted MRI in basilar occlusion treated with intra-arterial t-PA. 1054 94

Contrast agent free time-of-flight magnetic resonance angiography (TOF-MRA) was applied to the intraluminal thread occlusion model of experimental stroke in rat. It was combined with perfusion- and diffusion-weighted imaging (PWI and DWI) sequences to correlate occlusion and reopening of the middle cerebral artery with alterations in these well-established magnetic resonance sequences. Since TOF-MRA can be repeated without limitations, the time course of vascular patency is demonstrated during an experimental period of up to 8 h (2 h control, 1 h ischemia, 3-6 h reperfusion). With an acquisition time of 10 min, TOF-MRA proved to be suitable to analyze the vascular state of occlusion and reperfusion repetitively in longitudinal studies. Spatial resolution was sufficient to observe neurovascular structural details. In eight out of 10 animals complete vessel occlusion by the intraluminal thread could be validated by an entirely extinguished signal of the ipsilateral middle cerebral artery (MCA) in the angiograms. This was in accordance with a perfusion deficit in the MCA vascular territory detected by PWI (reduction to 30.4 +/- 7.4% relative to contralateral side) and a disturbance of water ion homeostasis monitored by DWI in this area. One animal showed a delayed occlusion after 30 min of MCA occlusion, in another animal vessel occlusion failed. In seven out of the eight successful occlusion experiments there was immediate reperfusion after withdrawal of the thread. One animal showed a delayed reperfusion after suture retraction. Remarkable hemispheric differences in vascular branching of the MCA could be recognized in three out of 10 animals. In conclusion, TOF-MRA is considered a helpful method to survey even in small laboratory animals the correct time course of vascular occlusion and reopening in experimental ischemia, and provides complementary information to the tissue perfusion status monitored by PWI and the ischemic lesion territory detected by DWI.
 ...
PMID:MR angiographic investigation of transient focal cerebral ischemia in rat. 1147 49

The use of T2*-weighted sequences has been advocated for early differentiation between hematoma and ischemia in patients with acute stroke. Early hemorrhagic transformation of ischemic stroke is an adverse event which may occur under treatment and may impair the prognosis: our aim is to evaluate the ability of T2*-weighted gradient-echo sequence (T2* GRE) to detect post-ischemic cerebral hemorrhage. The imaging procedure included: (1) baseline CT scan at admission. (2) MRI performed within 24 h of therapy onset including: (a) dual fast spin echo T2 sequence, (b) axial isotropic echoplanar diffusion-weighted imaging sequence, (c) conventional T2* GRE, and (d) 3D TOF turbo MRA. Post-ischemic cerebral hemorrhage was diagnosed if T2* GRE detected a focal intraparenchymal area of signal loss. The diameter of this lesion had to be more than 5 mm in order to eliminate past microbleeds. (3) Patients who showed an early suspicion of bleeding on MRI promptly had a second CT scan, and, if this one was negative for bleeding, another CT scan was performed 1 day later. All the other patients had a control CT scan during the first week. Forty-five consecutive patients have been included. T2* GRE showed intracranial bleeding in seven. The diagnosis of post-ischemic cerebral bleeding was confirmed by CT in all patients. Control CT scans did not reveal any post-ischemic cerebral hemorrhage in patients with negative MRI. In one case, hemorrhage was seen earlier on MRI than on CT scan. In conclusion, T2* GRE appeared to be at least as efficient as CT scan in the detection of early post-ischemic cerebral hemorrhage.
 ...
PMID:MRI of acute post-ischemic cerebral hemorrhage in stroke patients: diagnosis with T2*-weighted gradient-echo sequences. 1168 94

The presence of a thrombus on initial arteriography is directly related to the baseline NIHSS score. Magnetic resonance angiography (MRA) offers a noninvasive and rapid assessment of large cerebral vessel patency. We aimed at evaluating (1) the baseline NIHSS score as a tool for predicting the likelihood of an occluded artery on MRA and (2) the course of stroke within the first week according to the presence of a cerebral arterial occlusion. Patients were enrolled in this prospective study according to the following criteria: (1) acute cerebral ischemia with a neurological deficit lasting >1 h, and (2) brain MRI performed within 24 h of stroke onset. The NIHSS score assessment was performed on admission and at day 1 and day 7. The MRI protocol included: (1) T2-weighted Turbo spin echo, (2) echo-planar imaging isotropic diffusion, (3) T2*-gradient echo sequence, and (4) time of flight MRA (3D TOF Turbo MRA). The presence of a symptomatic cerebral arterial occlusion on MRA was systematically screened. Fifty-four patients were studied. Median age was 60 years. Mean time from stroke onset to NIHSS assessment was 170 +/- 95 min. The mean baseline NIHSS score was 13.5 +/- 7.3. The mean time from stroke onset to MRI was 384 +/- 171 min. MRA was readable in 50 cases. An arterial occlusion was detected in 23 patients (46%). The median baseline NIHSS score was significantly higher in the group of patients with occlusion than in the group of patients without occlusion (18 vs. 7, p = 0.01). The predictive probability to demonstrate an arterial occlusion was related to the baseline NIHSS score. None of the patients with an NIHSS score of 1-6 (11 patients) had visible occlusion, whereas 9 (43%) out of 21 patients with an NIHSS score of 7-15 and 14 (78% ) out of 18 patients with an NIHSS score above 16 had an arterial occlusion. For an increase by one point in the NIHSS score, the odds ratio for the presence of occlusion was 1.28 (95% CI: 1.11-1.46). The course of the stroke as assessed by follow-up NIHSS score was significantly more severe if an occlusion was detected. Median day 0, day 1 and day 7 NIHSS score were, respectively, 18, 16 and 13 in patients who had an occlusion versus 7, 4 and 0 in patients who had no visible occlusion (p < 0.01). A direct relation between the baseline NIHSS score and the likelihood of the presence of an occlusion on initial MRA is demonstrated. The presence of a cerebral arterial occlusion on MRA is significantly linked to a poor neurological outcome.
 ...
PMID:Early detection of cerebral arterial occlusion on magnetic resonance angiography: predictive value of the baseline NIHSS score and impact on neurological outcome. 1201 45

NCE MRA can provide the authors with useful diagnostic information in patients suffering from intracranial vascular disease, often leading to improved or altered treatment decisions. Most centers have used 3D TOF for evaluation of stroke-the most common cerebral vascular disease. Because of slow and disturbed flow, conventional 3D TOF MRA tends to overestimate stenotic lesions and occluded arteries and this can confound neurovascular assessment in stroke patients. Post contrast 3D TOF techniques provide a more robust and more specific method for imaging the intracranial circulation that overcomes the drawbacks of conventional 3D TOF. In the setting of acute ischemic stroke, the authors have found that the combination of conventional and CE 3D TOF MRA improves their overall diagnostic ability. Dynamic and time-resolved CE MRA techniques have evolved rapidly. Time-resolved CE MRA, in particular, is emerging as a useful technique for imaging dynamic vascular pathologies such as AVMs. Unfortunately, time-resolved MRA of the intracranial circulation provides images with low spatial resolution and is currently limited to subsecond frame rate 2D acquisitions, and less than 2 seconds frame rates for 3D acquisitions. Nevertheless, like in other vascular regions, CE MRA represents a milestone for non-invasive intracranial vascular imaging. The continuing development of CE MRA techniques and of new contrast agents will lessen the need for intra-arterial angiography in the future.
 ...
PMID:Contrast-enhanced MR angiography of the intracranial circulation. 1501 13

In brain, a brief ischemic episode induces protection against a subsequent severe ischemic insult. This phenomenon is known as preconditioning-induced neural ischemic tolerance. An understanding of the molecular mechanisms leading to preconditioning helps in identifying potential therapeutic targets for preventing the post-stroke brain damage. The present study conducted the genomic and proteomic analysis of adult rat brain as a function of time following preconditioning induced by a 10-min transient middle cerebral artery (MCA) occlusion. GeneChip analysis showed induction of 40 putative neuroprotective transcripts between 3 to 72 h after preconditioning. These included heat-shock proteins, heme oxygenases, metallothioneins, signal transduction mediators, transcription factors, ion channels and apoptosis/plasticity-related transcripts. Real-time PCR confirmed the GeneChip data for the transcripts up-regulated after preconditioning. Two-dimensional gel electrophoresis combined with MALDI-TOF analysis showed increased expression of HSP70, HSP27, HSP90, guanylyl cyclase, muskelin, platelet activating factor receptor and beta-actin at 24 h after preconditioning. HSP70 protein induction after preconditioning was localized in the cortical pyramidal neurons. The infarct volume induced by focal ischemia (1-h MCA occlusion) was significantly smaller (by 38 +/- 7%, p < 0.05) in rats subjected to preconditioning 3 days before the insult. Preconditioning also prevented several gene expression changes induced by focal ischemia.
 ...
PMID:Putative endogenous mediators of preconditioning-induced ischemic tolerance in rat brain identified by genomic and proteomic analysis. 1503 Mar 91

Amyloid beta-peptide (Abeta) cytotoxicity, the hallmark of Alzheimer's disease, implicates oxidative stress in both neurons and vascular cells, particularly endothelial cells. Consequently, antioxidants have shown neuroprotective activities against Abeta-induced cytotoxicity. Among the different antioxidants used in both in vitro and in vivo studies, 17beta-oestradiol (E2) has garnered the most attention. Oestrogen attenuated Abeta(E22Q)-induced toxicity in neurons but failed to protect endothelial cells. Here we show that E2-mediated activation of endothelial nitric oxide synthase (eNOS) increases the production of nitric oxide (NO), which, under Abeta(E22Q)-induced oxidative damage, results in the formation of peroxynitrite and increased nitration of tyrosine residues. Inhibition of eNOS prevents nitrotyrosination and permits E2-mediated protection against Abeta(E22Q) on endothelial cells. The main nitrotyrosinated proteins in the presence of E2 and Abeta(E22Q) were identified by MALDI-TOF mass spectrometry. These proteins are key players in the regulation of energy production, cytoskeletal integrity, protein metabolism and protection against oxidative stress. Our data highlight the potential damaging consequences of E2 in vascular disorders dealing with oxidative stress conditions, such as cerebral amyloid angiopathy, stroke and ischaemia-reperfusion conditions.
 ...
PMID:Lack of oestrogen protection in amyloid-mediated endothelial damage due to protein nitrotyrosination. 1581 16

An exhaustive analysis of metabolites in hair samples has been performed for the first time using ultra performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC-ESI-TOF-MS). The hair samples were collected from spontaneously hypertensive model rats (SHR/Izm), stroke-prone SHR (SHRSP/Izm) and Wistar Kyoto (WKY/Izm) rats, and were analyzed by UPLC-ESI-TOF-MS; a multivariate statistical analysis method, such as the principal component analysis (PCA), was then used for screening the biomarkers. From the samples derived from the group of SHRSP/Izm at weeks 10, 18, 26 and 34, we successfully detected a potential biomarker of stroke, which existed at much higher concentrations as compared with that in the other groups. However, a significant difference could not be found at weeks less than 7 before the rats were subjected to stroke and hypertension. In addition, the present method was applicable to screening not only the disease markers, but also the markers related to aging. The method utilizing hair samples is expected to be quite useful for screening biomarkers of many other diseases, and not limited to stroke and hypertension.
 ...
PMID:Metabolic profiling of rat hair and screening biomarkers using ultra performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry. 1803 54


1 2 3 4 5 6 7 Next >>