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

Migraine has been associated with diseases considered to be related to extracellular matrix disorders--in particular, cervical artery dissection. In this population-based study, we found a highly significant association between migraine and the activity of serum elastase, a metalloendopeptidase degrading specific elastin-type amino acid sequences. Such enzymes are involved in matrix degradation. This association was seen in both sexes and was stronger for migraine with aura. These findings could help in the understanding of why patients with migraine are at higher risk of stroke. Further study is needed to establish whether extracellular matrix abnormalities play a broader role in the pathophysiology of migraine.
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PMID:Serum elastase activity is elevated in migraine. 1080 37

The bulbus arteriosus of teleost fish acts as an elastic reservoir that dilates during ventricular systole to store a large part of the cardiac stroke volume. Despite its functional importance, the knowledge of the structure of the bulbus wall is still fragmentary. We have undertaken a series of studies in order to establish a general morphological plan of the teleost bulbus. The bulbus arteriosus of the European eel is studied here by means of conventional light, and transmission and scanning electron microscopy. The inner surface of the bulbus wall is irregular due to the presence of branching ridges that flatten and disappear toward the ventral aorta. The ridge surface is covered by flattened endocardial cells that show moderately dense bodies. In the ridge tissue, cells near the endocardium are mostly undifferentiated and appear isolated in a loose filamentous matrix. Ridge cells progressively cluster toward the middle layer, become surrounded by a dense matrix, and adopt characteristics typical of smooth muscle cells. This suggests the existence of a differentiation gradient. The middle layer is formed by typical smooth muscle cells embedded in a meshwork matrix that contains thin and thick filaments. Stretching of this meshwork suggests an active role of smooth muscle cells in bulbus wall dynamics. Furthermore, large areas of the extracellular space are occupied by elastin-like material. The amount of this material decreases toward the external layer. Collagen is demonstrated across the entire thickness of the bulbus wall, its amount and organization increasing from the inner toward the outer bulbus surface. The existence of matrix gradients should progressively increase wall strength, maintaining bulbus dilation within safe physiological parameters. The epicardium is formed by flattened cells that contain numerous pinocytotic vesicles, suggesting an active interchange of solutes with the pericardial cavity.
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PMID:Light and electron microscopy of the bulbus arteriosus of the European eel (Anguilla anguilla). 1097 Oct 42

During pericardial development or disease, changes in diastolic filling pressure and chamber volumes lead to changes in pericardial stress/strain state. These changes may be transduced into altered cellular synthesis of connective tissue proteins. To study the underlying mechanisms, we have constructed a system in which tissue strips may be subjected to a range of physiologically relevant load-elongation waveforms while being maintained under optimal tissue culture conditions. One sample grip is attached to a 500 g load cell and the other to a linear stepper motor. Load or stroke waveforms and feedback control are achieved under computer control. For preliminary studies, strips of fetal ovine pericardium (127-132 days gestation) and juvenile bovine pericardium (6 months) were subjected to ramp-and-hold loading for 24 hr in culture medium containing tritiated proline. At the end of the experiment, pericardial collagen and elastin were purified biochemically and assessed for tritium content. Preliminary results indicate that loading produced a significant 16% decrease in collagen synthesis (p < 0.02, cpm/mg wet weight) but no change in elastin synthesis. This novel system is a valuable tool for further studies of mechanotransduction in developing, normal, and pathological cardiac tissues.
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PMID:A computer-controlled system for mechanostimulation of tissues in culture: a preliminary study of protein synthesis in the pericardium. 1114 85

Homocysteinemia in humans is associated with vascular complications that increase the risk for atherosclerosis and stroke. Animal studies have shown that the disease is multifactorial and includes lesions associated with the elastin component of the extracellular matrix. In the following experiments we have used the aortas from rapidly growing chicks to assess the cause of the elastin defects resulting from homocysteinemia. Day-old chicks were fed diets containing varying amounts of DL-methionine, DL-homocysteine, homocysteine thiolactone or DL-cysteine for periods up to 9 wk. Three weeks after feeding 2% DL-methionine the plasma methionine was elevated > 20-fold, whereas plasma homocysteine was more than 3-fold normal plasma values. The aortas showed severe histopathology, evidenced by the pronounced separation of elastic lamellae with marked smooth muscle proliferation and, in some instances, aneurysms. There was no evidence of decreased desmosine content or a significant reduction in lysyl oxidase in the aortas from the treated groups compared to those from controls. Increasing other dietary factors such as the vitamins required for methionine metabolism had no effect on the development of the vascular lesions. Twenty to 30% of the chicks fed the high methionine diets exhibited severe neurological problems, expressed as tonic contractions or seizures. Electron microscopy revealed disordered aortic elastic fibrils, associated with either an absence of or disrupted assembly of microfibrils. Immunohistochemical studies demonstrated a loss of fibrillin-2 immunoreactivity in the aortas of chicks fed 2% methionine. The studies suggest that elevated plasma methionine or its metabolites disrupt normal microfibril configuration, leading to the assembly of aberrant elastic fibers.
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PMID:Fibrillin-2 defects impair elastic fiber assembly in a homocysteinemic chick model. 1216 53

Systolic blood pressure has a continuous, graded, strong, independent, and aetiologically significant relationship to mortality from coronary heart disease, stroke, and all cardiovascular diseases, as well as to all-cause mortality and life expectancy. Angiotensin II (AII) may be intimately involved in the pathogenesis of systolic hypertension through multiple mechanisms, including decreasing the elastin content and increasing the collagen content of the arterial wall, thickening and fibrotic remodelling of the vascular intima, and proliferating smooth muscle cells in the arterial wall, resulting in increased thickness, stiffening, and partial loss of contractility. AII antagonists may therefore offer hitherto unrecognized benefits (independent of blood pressure) on age-related vascular damage and provide particular benefits in patients with systolic hypertension. Recent evidence has demonstrated that losartan offers cardiovascular outcomes benefits in isolated systolic hypertension (ISH) associated with an excellent tolerability profile. This, in patients with ISH, AII antagonists more facilitate systolic BP control, providing cardiovascular protection and offering an excellent risk-benefit profile.
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PMID:Treatment of systolic hypertension: spotlight on recent studies with angiotensin II antagonists. 1545 5

Subarachnoid haemorrhage (SAH) is a subtype of stroke caused by the rupture of an intracranial aneurysm. Genetic factors play an important part in the pathogenesis of SAH and intracranial aneurysms. SAH and intracranial aneurysms are complex in origin, involving the interaction of several genes and environmental factors. A disruption of the extracellular matrix of the arterial wall, which provides strength and elasticity to intracranial arteries, is a likely factor in the pathophysiology of intracranial aneurysms. In this review, we discuss the genetic association, linkage, and gene-expression studies of SAH and intracranial aneurysms. At present, four genome-wide linkage studies have identified genetic loci for intracranial aneurysms. Interestingly, three of these loci include functional candidate genes coding for structural proteins of the extracellular matrix. Of these genes, elastin and collagen type 1A2 are the most promising candidates, because allelic association with intracranial aneurysms has also been shown for these genes. However, variation in these two genes only explains a small proportion of the genetic factors involved in intracranial aneurysms. Future studies need to identify new candidate genes to help unravel the pathophysiology of the disorder.
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PMID:Genetics of intracranial aneurysms. 1572 28

There are significant associations between moderate increases in serum homocysteine and three cardiovascular diseases: ischemic heart disease, deep vein thrombosis and pulmonary embolism, and stroke. An association between the presence of abdominal aortic aneurysm and elevated homocysteine plasma levels has been indicated. Although chronic systemic hypertension is the most common factor predisposing the aorta to dissection, homocysteinemia has never been known as the risk for aortic dissection except for that with Marfan syndrome. Homocysteinemia is suggested to be the risk for aortic dissection in Marfan syndrome and spontaneous cervical artery dissection. Reduced fibrillin-1 deposition into the extracellular matrix is found not only in Marfan syndrome but also in isolated ascending aortic aneurysm and dissection. The reduced matrix deposition produces a mild form of weakness of elastic tissue, which predisposes to ascending aortic aneurysm and dissection in patients who do not have the Marfan syndrome. The defect in fibrillin-1 leads to: (1) formation of elastin that is abnormally aggregated and more easily degraded by matrix metalloproteinases than is normal elastin; (2) upregulation of the synthesis of matrix metalloproteinases; (3) progressive destruction of connective tissue by these enzymes; (4) development of thoracic aortic aneurysms. Homocysteine causes premature breakdown in the arterial elastic fibers by activation of the elastolytic activities. Irreversible homocysteinylation of long-lived proteins should lead to cumulative damage and progressive clinical manifestations, and fibrillin-1 is seen as the paradigm of extracellular connective tissue proteins that are specially susceptible to homocysteine (and presumably homocysteine thiolactone) attack. The authors hereupon propose a novel hypothesis that homocysteine plays an important role in development of aortic dissection and that homocysteinemia is one of the risk factors for aortic dissection.
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PMID:Homocysteinemia is a risk factor for aortic dissection. 1578 May 1

Since the introduction of echocardiography the diagnosis of papillary fibroelastomas (PFEs) in living patients has increased. They are second most common after myxomas representing 10% of cardiac tumors. The present case is of a patient with recurrent cerebrovascular accidents and documented protein S deficiency who continued to stroke despite adequate anticoagulation. Mitral valve PFE was suspected on echocardiography and confirmed at surgical excision. Two large studies published in the last decade describe the echocardiographic and clinical characteristics of PFEs which although are histologically benign, may present with a clinical course of devastating consequences owing to its strategic location within the cardiac structures. Echocardiography, particularly transesophageal echocardiography (TEE), provides the necessary anatomical resolution and detail to ascertain location, extent of involvement, and hemodynamic implications. Tissue diagnosis is based on characteristic histopathological features of avascular fronds lined by endothelial cells, containing varying amounts of elastin. The echocardiographic characteristics along with treatment options are reviewed.
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PMID:Recurrent strokes in a young patient with papillary fibroelastoma: a case report and literature review. 1691 35

Aortic atheromatous disease is associated with stroke in both the ambulatory and perioperative setting. In addition to atheromatous deposits, a reduction in the compliance of the aorta takes place as elastin fibers are replaced by collagen fibers. Both of these distinct processes, termed atherosclerosis, can easily be measured using transesophageal echocardiography during cardiac surgery. A review of the literature demonstrates many studies supporting the benefit of transesophageal echocardiography examination of the aorta for reducing stroke following cardiac surgery, through modification of surgical techniques. There have also been attempts by surgeons to remove atheromatous lesions from the aorta during cardiac surgery. Unfortunately, these procedures currently have a high perioperative mortality. Finally, medical therapy such as warfarin or statins may help reduce the incidence of stroke following heart surgery.
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PMID:Aortic assessment for cardiac surgical procedures. 1695 42

Effects of Chlorella regularis (dried cell powder)--cultured axenically under heterotrophic conditions, and provided as a dietary supplement--and its fractions on the blood pressure, cerebral stroke lesions, and life-span of stroke-prone spontaneously hypertensive rats (SHRSP/Izm) were investigated. When SHRSP were fed on diets with supplemented Chlorella to a commercial diet (Funabashi SP), elevation of blood pressure was significantly lower in the Chlorella groups than in the control group. At 21 wk of feeding, serum total cholesterol was significantly lower in the Chlorella groups than in the control group. Histopathological examination revealed cerebral vascular accidents in the brains of the control group, but those of Chlorella groups showed apparently low incidence compared to the control group. The average life-span of the Chlorella groups were significantly longer than that of the control group (p < 0.001). Chlorella powder was fractionated into three fractions, lipid-soluble, hot water-soluble, and residual fractions. The diets supplemented with lipid or residual fractions equivalent to 10% Chlorella significantly suppressed elevation of blood pressure in SHRSP, and then decreased the incidence rate of cerebral vessel lesions compared to the control group. Chemical analysis revealed that the lipid fraction contained large quantities of antioxidants, including carotenoids (especially lutein) and others, and phospholipids involved in aorta collagen and elastin metabolism; the residual fraction contained high concentrations of arginine, enhancing the function of blood vessels. The control diet contained only a little these substances. These experimental results suggest that the beneficial effect of Chlorella on SHRSP is caused by the synergistic action of several ingredients of Chlorella, which play a role in sustention of a vascular function of rats.
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PMID:Effect of chlorella and its fractions on blood pressure, cerebral stroke lesions, and life-span in stroke-prone spontaneously hypertensive rats. 1733 May 10


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