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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain types of stroke, TIAs and Amaurosis Fugax can result from atheroembolism from the Carotid bifurcation. This study was undertaken to establish qualitative and quantitative baseline criteria in an animal model for future studies evaluating the effectiveness of thrombolytic and cholesterol emulsifying agents which could eliminate or reduce experimentally induced occlusive atheroembolic lesions. Sixteen male NZW rabbit received sublethal intracarotid injections of human atheroma. After 24 hours the animals were sacrificed, having their brains fixed by cardiac perfusion. Each left hemisphere was coronally sliced anteroposteriorly at 3 mm intervals, and paraffin or methacrylate sections were taken from each slice and stained with H & E or Toluidine Blue. Samples from infarcted tissue were processed for TEM observation. Each section was projected onto the digitizing tablet of a Microplan II image analysis system. The perimeter length, area and maximum diameter were measured for each infarct. The regional distribution of each infarct per section level was recorded on stereotaxic atlas diagrams. The vascular lesions were characteristic of cerebral atheroembolic occlusions. The infarcts were distributed primarily in the cortical and subcortical regions, and were largest in the distribution territory of the Middle Cerebral artery. The morphometric parameters of the infarcts were highly variable at all slice levels.
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PMID:An assessment of the extent and distribution of experimentally induced cerebral atheroembolic vascular occlusions and infarcts. 378 23

The state of water in cerebral ischemia was studied by using the proton nuclear magnetic resonance (1H-NMR) method. Cerebral ischemia was induced experimentally in Mongolian gerbils by unilateral ligation of the common carotid artery. Longitudinal (T1) and transverse (T2) relaxation times of the ischemic brain were measured with a pulse FT-NMR spectrometer and the water content was determined by the wet/dry method. Quantitative analysis of the relaxation times was performed sequentially during the initial 7 hours following ligation and the data were compared with those of brain edema previously reported by S. Naruse in the rat. Characteristic findings in brain ischemia include prolongation of the slow component of T2 and increase in the water content. A quantitative comparison of relaxation rate and water content demonstrates that ischemic brain edema in Mongolian gerbils is different from cytotoxic and vasogenic types of brain edema. When R2 (1/T2) was plotted against the water content, the slope value of ischemia in the gerbil was between the slope values of the TET intoxication and cold injury induced edemas reported previously. From these results, it might be said that ischemic brain edema includes both the cytotoxic and vasogenic types of brain edema. Glycerol was demonstrated to affect brain ischemia by decreasing the water content and by shortening the slow component of T2. By analysis of the relaxation times and water content, we examined the pathophysiological characteristics of water molecules in ischemic brain tissue.
Stroke
PMID:Proton NMR relaxation times in ischemic brain edema. 381 Jul 13

Early stage embryos of the starfish Pisaster ochraceus exhibit one cilium per cell which is primarily involved in locomotion. SEM observations have demonstrated two types of microvilli "stage horn"-like and "finger-like" microvilli (CMs), both of which probably serve to anchor and support the hyaline layer (HL). The CMs arise from the cellular membrane a short distance from the base of the ciliary shaft and form a circle around the base of each cilium. This arrangement is found in embryos and larvae as well as in adult tissues of many other marine organisms. TEM observations of material prepared by freeze substitution has demonstrated that the HL unites the circle of CMs and forms two collars. The outer ECM collar is single and attached directly to the CMs, while the inner collar consists of multiple rings of ECM located between the cilium and the CMs. The inner collar elements are not attached to the cilium but are attached to the inner aspects of the CMs by a complex arrangement consisting of a loop of ECM and two short ECM fibers. The arrangement of the ECM of the collars could provide an excellent way to transmit the movements of the cilium to the surrounding microvilli. Although the bases of the CMs always encircle the ciliary shaft, the shafts of the CMs are seen in different positions. This suggests that the CM/ECM collar may be able to change position relative to the cilium. Confocal laser scanning microscopy demonstrates that the CMs contain phalloidin positive material which extends into a phalloidin positive region located in the apex of the cells. The CMs and apical web contain microfilaments which are probably actin and could be involved in movement of the CMs. A movable circle of CMs with their associated ECM could represent a mechanism to sense the position of the cilium and/or to define the direction and extent of the stroke.
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PMID:The microvilli and hyaline layer of embryonic asteroid epithelial collar cells: a sensory structure to determine the position of locomotory cilia? 769 Oct 38

To evaluate whether hemostatic abnormalities contribute to the increased risk of stroke, the authors prospectively studied the hemostatic markers (HM) (beta-TG, PF4, FPA, TAT, PIC, D-dimer) in 34 elderly patients with atrial fibrillation (Af) without a history of stroke (mean age 79.2) and 14 age-matched controls. In the Af group FPA was significantly higher than in the control group (p < 0.05). Among them, 8 patients showed a similar abnormal HM pattern as in cardioembolic is chemic stroke and in these, 4/8 patients had valvular disease (VD), 2/8 had hypertension (HT), 2/8 had congestive heart failure (CHF), 1/8 had diabetes mellitus (DM) and 1/8 had hyperlipidemia (HL). Eight patients showed the same abnormal HM pattern as atherothrombotic is chemic stroke and of these, 2/8 had HT as complications. Five patients showed combination of a HM abnormal pattern, that was observed in cardioembolic and atherothromboic ischemic stroke. The other 13 patients showed a normal HM pattern, were in these patients, 4/13 had HT, 1/13 had DM, 1/13 had VD, and 1/13 had CHF. The patients with VD complication tended to have embolic HM abnormality. Contrary to previous reports, nonvalvular Af patients do not necessarily tend to have high risk of cardioembolic stroke. Our data suggest difficulties in clinical diagnosis among Af patients with ischemic stroke whether it is cardio embolic or atherothrombotic.
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PMID:[Alterations of hemostatic markers in elderly patient with atrial fibrillation without a history of stroke]. 833 32

The authors studied whether haemostatic abnormalities connected with the development of cerebral circulatory disturbances can be demonstrated in young stroke patients in whom Doppler and angiographic examination failed to reveal deviations indicative of stroke. They determined the in vivo activation of the coagulation system (TAT, F 1 + 2), the degree of secondary fibrinolysis (D-dimer), the plasma levels of the markers of fibrinolysis, with special regard to inhibitors: plasminogen activator inhibitor (PAI-1), alpha 2 antiplasmin (alpha 2 AP), alpha 2 macroglobulin (alpha 2 M), the frequency of pathologic serum lipoprotein (a)-Lp(a)-values and the association of PAI-1 and Lp(a) with the fibrinolytic system. They conclude that in the acute phase of the disease, the TAT and F 1 + 2 values were significantly elevated compared to the control, without change in the D-dimer value. The results suggest that in the tested period increased thrombin generation dominated and it significantly surpassed plasmin activity since the D-dimer values of that period did not indicate substantial increase in secondary fibrinolysis. The results of the study were separately analyzed in acute, chronic TIA and stroke groups. In the TIA and acute group the F 1 + 2 values, while in stroke the TAT values were more elevated. The in vitro fibrinolytic capacity of the patients significantly decreased compared to controls, showing significant correlation with the Lp(a) level, but not with the PAI value. Examination of the marker molecules renders possible to assess the degree of hypercoaguability and of endogenous lysis. Their knowledge is held important for judging the progression of the disease and the therapeutic consequences.
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PMID:[Hemostatic abnormalities in ischemic stroke]. 981 Jan 64

To determine the presence of a 'hypercoagulable state' as assessed by indices of thrombin and plasmin generation and of the amount of fibrin that is lysed, in patients with stable coronary, cerebral and peripheral arterial disease a population-based cross-sectional study was performed. From a population-based cohort comprising 7983 men and women aged 55 years and over, we randomly selected 127 subjects with a history of myocardial infarction, 124 with a history of stroke and/or transient ischemic attack, 131 patients with peripheral arterial disease and 263 control subjects in the same age group without arterial disease. Subjects using anticoagulant drugs were not selected. F1+2, TAT, and PAP were not associated with a history of cardiovascular events, nor with peripheral arterial disease. In contrast, positive associations were found for D-Dimer. Mean D-Dimer level was 40 microg/l (95% CI 35, 44) in control subjects; 53 microg/l (47, 61) in those with a history of myocardial infarction and 51 microg/l (45, 58) in those with a history of stroke and or transient ischemic attack. D-Dimer increased gradually with increasing severity of peripheral atherosclerosis; a decrease in ankle/arm systolic blood pressure ratio of 0.1 was associated with an increase in D-Dimer of 3.9 microg/l (p<0.01). This was more pronounced in subjects with higher F1+2, TAT and PAP concentration. In conclusion, the markers of onset of coagulation F1+2, TAT and PAP are not associated with the presence of arterial disease, but increased levels of these markers are necessary for the positive association between D-Dimer and arterial disease.
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PMID:Activation products of the haemostatic system in coronary, cerebrovascular and peripheral arterial disease. 1124 39

The delivery of proteins across the blood-brain barrier is severely limited by the proteins' size and biochemical properties. Eleven-amino acid human immunodeficiency virus TAT protein is able to cross cell membranes even when coupled with larger peptides. We evaluated whether TAT-Bcl-X(L) fusion protein is protective in focal ischemia. Mice underwent 30 or 90 minutes of intraluminal middle cerebral artery thread occlusion. TAT-Bcl-X(L), TAT-beta-galactosidase, or TAT-GFP (0.6 nmol each) were applied intravenously over 10 minutes either 1 hour before or immediately after ischemia. Additional animals received no TAT protein infusions. We show that the brain tissue is progressively transduced with TAT proteins within 3 to 4 hours after intravenous delivery. We provide evidence that TAT-Bcl-X(L) treatment reduces infarct volume and neurological deficits after long ischemic insults lasting 90 minutes, when applied both before and after ischemia. After short insults, lasting only 30 minutes, TAT-Bcl-X(L) further diminishes the number of caspase-3-reactive and DNA fragmented cells and increases the number of viable neurons in the striatum. Our results indicate that TAT fusion proteins are elegant and powerful tools that might be of clinical interest for stroke treatment, because factors may be intravenously applied. Thus, fusion proteins may open fascinating perspectives for future research.
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PMID:Intravenous TAT-Bcl-Xl is protective after middle cerebral artery occlusion in mice. 1240 59

A 27-year-old woman was admitted to our hospital because of headache, fever and right neck pain. Neurological examination revealed mild meningeal signs, and hyper-reflexia in all extremities. In the laboratory tests, white-cell count was 13,000/mm3, rheumatoid factor(RF) and C-reactive protein(CRP) were positive. The cerebro-spinal fluid showed pleocytosis (56/mm3, neutorophils and lymphocytes were 26 and 28, respectively). Thus, she was diagnosed as aseptic meningitis. A few days later, she had weakness and dysesthesia of the right face and the left extremities. Pulse therapy with intravenous methylprednisolone was started. A magnetic resonance imaging (MRI) of the brain showed a hemorrhagic infarction in the right parietal lobe. In hemostatic markers, thrombin-antithrombin III complex(TAT; 106 ng/dl), D-dimer 1234 ng/dl, prothrombin fragment 1 + 2(F1 + 2; 2.36 nmol/L), beta-thromboglobulin (beta TG; 4,300 ng/dl) and platelet factor 4 (PF-4; 1,770 ng/dl) were extremely elevated. On duplex ultrasonography, a low echo lucent plaque was observed at the right internal carotid artery and the mean blood flow velocity in the right carotid artery was decreased. She was placed on oral prednisolone and warfarin for suspected stroke due to hypercoagulability associated with vasculitis. Afterwards, she discharged from our hospital. Two months later, she was readmitted to our hospital because of irregular menses and vaginal bleeding. Endometrial uterus biopsy was conducted, which revealed a grade I endometrioid adenocarcinoma. She was under total uterectomy without tumor recurrence. After the radical operation, white-cell count, RF, CRP, TAT, D-dimer, F1 + 2, and beta TG were normalized, and the mean flow velocity of the right common carotid artery was increased. Thereafter, she did not experience stroke recurrence. Therefore, we speculated that she had stroke due to hypercoagulability in association with malignancy, that is Trousseau's syndrome. We also assumed that aseptic meningitis, brainstem encephalitis associated with vasculitis in this patient are other clinical variants of paraneoplastic syndrome through immunological mechanisms associated with malignancy. We emphasize that patients with Trousseau's syndrome can be associated with other paraneoplastic manifestations such as vasculitis as seen in this patient.
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PMID:[A young patient with endometrioid adenocarcinoma who suffered Trousseau's syndrome associated with vasculitis]. 1247 93

The TAT protein transduction domain (PTD) has been used to deliver a wide variety of biologically active cargo for the treatment of multiple preclinical disease models, including cancer and stroke. However, the mechanism of transduction remains unknown. Because of the TAT PTD's strong cell-surface binding, early assumptions regarding cellular uptake suggested a direct penetration mechanism across the lipid bilayer by a temperature- and energy-independent process. Here we show, using a transducible TAT-Cre recombinase reporter assay on live cells, that after an initial ionic cell-surface interaction, TAT-fusion proteins are rapidly internalized by lipid raft-dependent macropinocytosis. Transduction was independent of interleukin-2 receptor/raft-, caveolar- and clathrin-mediated endocytosis and phagocytosis. Using this information, we developed a transducible, pH-sensitive, fusogenic dTAT-HA2 peptide that markedly enhanced TAT-Cre escape from macropinosomes. Taken together, these observations provide a scientific basis for the development of new, biologically active, transducible therapeutic molecules.
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PMID:Transducible TAT-HA fusogenic peptide enhances escape of TAT-fusion proteins after lipid raft macropinocytosis. 1477 Jan 78

This review presents an overview of the highlights of major concepts involving the anatomical routes for the transport of macromolecules and the transmigration of cellular elements across the blood-brain barrier (BBB) during inflammation. The particular focus will include inflammatory leukocytes, neoplastic cells and pathogenic microorganisms including specific types of viruses, bacteria and yeasts. The experimental animal models presented here have been employed successfully by the authors in several independent experiments during the past twenty-five years for investigations of pathologic alterations of the BBB after a variety of experimentally induced injuries and inflammatory conditions in mammalian and non-mammalian animal species. The initial descriptions of endothelial cell (EC) vesicles or caveolae serving as mini-transporters of fluid substances essentially served as a springboard for many subsequent discoveries during the past half century related to mechanisms of uptake of materials into ECs and whether or not pinocytosis is related to the transport of these materials across EC barriers under normal physiologic conditions and after tissue injury. In the mid-1970's, the authors of this review independently applied morphologic techniques (transmission electron microscopy-TEM), in conjunction with the plant protein tracer horseradish peroxidase (HRP) to investigate macromolecular transport structures that increased after the brain and spinal cord had been subjected to a variety of injuries. Based on morphologic evidence from these studies of BBB injury, the authors elaborated a unique EC system of modified caveolae that purportedly fused together forming transendothelial cell channels, and later similar EC profiles defined as vesiculo-canalicular or vesiculo-tubular structures (VTS, Lossinsky, et al., 1999). These EC structures were observed in association with increased BBB permeability of tracers including exogenously injected HRP, normally excluded from the intercellular milieu of the CNS. Subsequent studies of non-BBB-type tumor ECs determined that the EC VTS and other vesicular structures were defined by others as vesiculo-vacuolar organelles (VVOs, Kohn et al., 1992; Dvorak et al., 1996). Collectively, these structures appear to represent a type of anatomical gateway to the CNS likely serving as conduits. However, these CNS conduits become patent only in damaged ECs for the passage of macromolecules, and purportedly for inflammatory and neoplastic cells as well (Lossinsky et al., 1999). In this review, we focus attention on the similarities and differences between caveolae, fused racemic vesicular bundles, endothelial tubules and channels (VTS and the VVOs) that are manifest in normal, non-BBB-type blood vessels, and in the BBB after injury. This review will present evidence that the previous studies by the authors and other researchers established a framework for subsequent transmission (TEM), scanning (SEM) and high-voltage electron microscopic (HVEM) investigations concerning ultrastructural, ultracytochemical and immunoultra-structural alterations of the cerebral ECs and the mechanisms of the BBB transport that occurs after CNS injury. This review is not intended to include all of the many observations that might be included in a general historical overview of the development of the EC channel hypothesis, but it will discuss several of the major contributions. We have attempted to present some of the structural evidence that supports our early contributions and those made by other investigators by highlighting major features of these EC structures that are manifest in the injured BBB. We have focused on currently established concepts and principles related to mechanisms for the transendothelial transport of macromolecules after CNS injury and also offer a critical appraisal of some of this literature. Finally, we describe more recent concepts of transBBB avenues for viruses, including HIV-1, bacterial and mycotic organisms, as well as inflammatory and neoplastic cell adhesion and migration across the injured mammalian BBB. Data from studies of EC-related adhesion molecules, both from the literature and from the author's experimental results and observations made in other laboratories, as well as from personal communications underscore the importance of the adhesion molecules in facilitating the movement of leukocytic, neoplastic cell and human pathogens across the BBB during inflammatory and neoplastic events. Exciting, ongoing clinical trials are addressing possible therapeutic intervention in neuroinflammatory diseases, including multiple sclerosis, by blocking certain glycoprotein adhesion molecules before cells have the ability to adhere to the ECs and migrate across the BBB. Approaches whereby inflammation may be reduced or arrested using anti-adhesion molecules, by restructuring EC cytoskeletal, filamentous proteins, as well as remodeling cholesterol components of the modified VTS are discussed in the context of developing future therapies for BBB injury and inflammation. Understanding new concepts about the mechanism(s) by which inflammatory cells and a variety of pathogenic microorganisms are transported across the BBB can be expected to advance our understanding of fundamental disease processes. Taken together, the literature and the author's experiences during the past quarter of a century, will hopefully provide new clues related to the mechanisms of transendothelial cell adhesion and emigration across the injured BBB, issues that have been receiving considerable attention in the clinical arena. Learning how to chemically modulate the opening and/or closure of EC VTS and VVO structural pathways, or junctional complexes prior to cellular or microorganism adhesion and breaching the BBB presents challenging new questions in modern medicine. Future studies will be critically important for the development of therapeutic intervention in several human afflictions including traumatic brain and spinal cord injuries, stroke, cancer, multiple sclerosis and conditions where the immune system may be compromised including HIV infection, infantile and adult meningitis.
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PMID:Structural pathways for macromolecular and cellular transport across the blood-brain barrier during inflammatory conditions. Review. 1502 15


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