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

DNA polymorphisms in genes encoding apolipoproteins (apo) A-I, C-III, B and E and angiotensin-converting enzyme (ACE) have been proposed to be associated with the risk of coronary artery disease (CAD). We studied whether the same genetic markers would also be associated with the occurrence and extent of atherosclerosis in cervical arteries. DNA samples from 234 survivors of stroke or a transient ischaemic attack aged 60 years or less were examined. The presence of atherosclerosis was assessed using aortic arch angiograms. The SstI polymorphism of apoA-I/C-III gene locus, the XbaI polymorphism of apoB gene, common apoE phenotypes and the insertion/deletion polymorphism of the ACE gene were analysed. The allele frequencies of the apoA-I/C-III, apoB, apoE or ACE gene did not differ between the groups with (n = 148) or without (n = 85) cervical atherosclerosis. However, when patients with at least one apoE4 allele and one X2 allele of apoB were combined and compared with those without either of them (E2E3 or E3E3 and X1X1), a significant association with the presence of cervical atherosclerosis was found (P = 0.03). The patients having the E2E3 phenotype had a significantly elevated serum triglyceride level compared with those with the E3E3 phenotype (P = 0.03). Serum high-density lipoprotein (HDL) cholesterol was lower in the patients with the E2E3 phenotype than in those with the E3E3 and E3E4 (P = 0.01 and P = 0.06, respectively). The apoB or ACE genotypes were not significantly associated with serum lipid or lipoprotein levels. There was no association between the ACE gene polymorphism and the occurrence of hypertension. In conclusion, the interaction of common apoB and apoE alleles may increase the risk of atherosclerosis in cervical arteries.
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PMID:Genetic risk factors and ischaemic cerebrovascular disease: role of common variation of the genes encoding apolipoproteins and angiotensin-converting enzyme. 966 3

In the lobster Homarus gammarus, rhythmic masticatory movements of the foregut gastric mill are generated by a small neural network in the stomatogastric ganglion. We have used EMG recordings from intact animals to analyse gastric network output in relation to cycle period before and after feeding. In pre-prandial conditions, muscles controlling lateral teeth closure and medial tooth protraction (driven by MG and GM motor neurons, respectively) express relatively constant, return stroke-like burst durations, but change to a variable-duration power stroke-like phenotype after feeding. In contrast, the LPG neuron-innervated lateral teeth opener muscle switches from power stroke to return stroke-like behavior. Thus alternate phases within a single motor program may invert their temporal properties according to the behavioral situation.
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PMID:Feeding-induced changes in temporal patterning of muscle activity in the lobster stomatogastric system. 977 21

Apolipoprotein (apo) E isoforms are key determinants of susceptibility to Alzheimer's disease. The apoE4 isoform is the major known genetic risk factor for this disease and is also associated with poor outcome after acute head trauma or stroke. To test the hypothesis that apoE3, but not apoE4, protects against age-related and excitotoxin-induced neurodegeneration, we analyzed apoE knockout (Apoe-/-) mice expressing similar levels of human apoE3 or apoE4 in the brain under control of the neuron-specific enolase promoter. Neuronal apoE expression was widespread in the brains of these mice. Kainic acid-challenged wild-type or Apoe-/- mice had a significant loss of synaptophysin-positive presynaptic terminals and microtubule-associated protein 2-positive neuronal dendrites in the neocortex and hippocampus, and a disruption of neurofilament-positive axons in the hippocampus. Expression of apoE3, but not of apoE4, protected against this excitotoxin-induced neuronal damage. ApoE3, but not apoE4, also protected against the age-dependent neurodegeneration seen in Apoe-/- mice. These differences in the effects of apoE isoforms on neuronal integrity may relate to the increased risk of Alzheimer's disease and to the poor outcome after head trauma and stroke associated with apoE4 in humans.
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PMID:Expression of human apolipoprotein E3 or E4 in the brains of Apoe-/- mice: isoform-specific effects on neurodegeneration. 1036 21

Vascular calcification is increasingly recognized as a significant contributor to cardiovascular morbidity and mortality as well as a biologically regulated process potentially subject to prevention and reversal. Both coronary and aortic calcification are common and influence plaque rupture, angioplasty and surgical complications, and compensatory enlargement. Aortic calcification increases aortic rigidity and contributes to cadiac ischemia, left ventricular hypertrophy, heart failure, and stroke. Calcification is also common in aortic valve leaflets further compounding adverse hemodynamic effects. Vascular calcification has often been attributed to "passive" crystallization. However, functional similarities between atherosclerotic lesions and bone contradict this view and indicate that it is no more "passive" than in embryonic bone formation or bone repair. Similarities include presence of all the major components of bone osteoid, bone regulatory factors, and subpopulations of artery wall cells that retain osteoblastic lineage potential. Several animal models for vascular calcification are available. Spontaneous vascular calcification occurs in null mice for matrix GLA protein (MGP), a small matrix protein of unknown function, and osteoprotegerin (OPG), known to modulate osteoclast differentiation. Vascular calcification may also be induced by feeding vitamin D and calcium or warfarin to normal animals, or by fat-feeding mice null for apoE or the LDL-receptor. Overall, regulation of vascular calcification is a growing field with surprising mechanisms and connections to other fields of biology.
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PMID:Regulatory mechanisms in vascular calcification. 1118 30

Although controversial, data on the genetic polymorphism of apoprotein E (APOE), methylenetetrahydrofolate (MTHFR) and paraoxonase (PON1) genes implicate their role in the development of cerebrovascular disease. The aim of this study was to assess the association of polymorphism of APOE, MTHFR and PON1 genes in 56 stroke and 36 carotid stenosis patients, and in 124 control subjects by PCR-restriction fragment length polymorphism analysis. In the stroke group a significantly different MTHFR genotype distribution (p=0.004, odds ratio for T/T of 17.571), but no significant difference in APOE and PON1 allele and genotype distribution compared to the control was found. The carotid stenosis group exhibited a significantly different APOE allele and genotype distribution (p=0.023, odds ratio APOEepsilon3epsilon4 of 4.24), but no significant difference in the MTHFR and PON1 allele and genotype distribution from the control group. The preliminary results obtained in this study revealed an association of the MTHFR and APOE gene polymorphism with cerebrovascular disease, suggesting a significant risk for stroke in subjects who are homozygous for the T allele and for carotid stenosis in subjects having APOEepsilon3epsilon4 genotype. Additional studies in larger patient groups are needed to confirm these observations.
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PMID:Polymorphism of apoprotein E (APOE), methylenetetrahydrofolate reductase (MTHFR) and paraoxonase (PON1) genes in patients with cerebrovascular disease. 2463 86

Clearance of infarct tissue would be an important process for tissue repair after a stroke. Delayed clearance may hamper reconstitution of the blood-brain barrier and glial boundary formation. Recent growing evidence has indicated that apolipoprotein E (APOE), a major apoprotein, plays an important role in lipid transport and homeostasis in the brain. The tissue in the infarction contains abundant lipids must be removed for tissue clearance. In the current study, the authors investigated APOE expression after focal ischemia and the functional role of APOE in tissue clearance using APOE-knockout mice. Expression of APOE was delayed, but marked, in immunohistochemistry and immunoblotting 7 days after permanent focal ischemia. Macrophages were found to express APOE in the infarct center. Infarct size was similar after focal ischemia between wild-type and APOE-knockout mice, although there was no APOE protein expression in knockout mice. However, clearance of infarct tissue 2 weeks after ischemia was significantly delayed in APOE-knockout mice compared with wild-type mice. The current study supports current thinking that APOE is a key molecule for tissue remodeling in the brain. Clearance of damaged tissue may be one of the important functions of APOE in the brain.
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PMID:Delayed, but marked, expression of apolipoprotein E is involved in tissue clearance after cerebral infarction. 1159 97

The behavioural effects of middle cerebral artery occlusion (MCAO) in apolipoprotein-E deficient (Apo-E KO) mice were investigated using a modified SHIRPA protocol and compared with effects in wild type littermate controls. The MCA was permanently occluded by insertion of an intraluminal filament to its origin on the Circle of Willis and behavioural responses were observed 24 h later. MCAO treatment caused a range of changes in the wild type mice whereas, few differences were observed in the Apo-E KO mice in the behavioural observation. In the rotarod task, MCAO operated wild type mice showed a significant reduction in performance compared with sham-operated and non-operated animals. In contrast, both sham and MCAO operated Apo-E KO mice showed significant impairment compared with non-operated controls. A significant reduction in performance was also observed in sham-operated Apo-E KO compared with sham-operated wild type mice. In locomotor activity tests, no significant reduction in activity was observed between non-operated and sham-operated wild type controls, whereas a significant reduction was found between sham operated and MCAO operated mice. In the Apo-E KO mice, both sham and MCAO-operated animals showed a reduction in locomotor activity compared with non-operated mice. Furthermore, Apo-E KO MCAO mice showed a worsened deficit in locomotor activity, which was significantly correlated with exacerbated cortical lesion volume, unlike wild-type MCAO mice. This study shows that Apo-E KO animals demonstrate an impaired functional recovery post surgery which may be further compounded by post experimental stroke and also demonstrates the utility of the SHIRPA test system for investigating behavioural changes in functional outcome post stroke.
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PMID:The behavioural effect of middle cerebral artery occlusion on apolipoprotein-E deficient mice. 1184 81

This study investigated the frequency of angiotensin-converting enzyme (ACE) genotypes, concentrations of total cholesterol (T-C), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), lipoprotein Lp (a), Established Risk Factor (ERF) ratio (total cholesterol/HDL-C), apolipoproteins A-I, A-II, apoBand apoE in 134 menopausal women aged 49.62 +/- 4.83 on oral hormone replacement therapy (HRT) (2 mg 17 beta estradiol plus 1 mg norethisterone acetate/day), during (mean +/- SD) 15.77 +/- 9.94 months. ACE genotypes of 134 menopausal women showed DD genotype in 48 (36%), ID genotype in 59 (44%), and II genotype in 27 (20%) women, with the mean body mass index (BMI) (kg/m2) of 26.34 +/- 4.02, systolic blood pressure (mm Hg) of 145.71 +/- 23.32, diastolic blood pressure of 95.28 +/- 12.88, pulse rate of 77.76 +/- 13.81, positive family history of myocardial infarction (MI) (23%) and stroke (22%); 26% were smokers and 6% consumed alcohol regularly. The mean levels of TC (mmol/l) were 5.72 +/- 1.25, TG (mmol/L) 1.63 +/- 0.82, HDL-C (mmol/L) 1.15 +/- 0.29, LDL-C (mmol/L) 3.98 +/- 1.31, lipoprotein Lp(a) (g/L) 0.16 +/- 0.24, ERF ratio 5.35 +/- 1.90, apolipoproteins (g/L): A-I 1.83 +/- 0.39, A-II 0.57 +/- 0.12, apoB 0.92 +/- 0.31, and apoE 0.08 +/- 0.04. The highest mean levels of T-C 5.89 +/- 1.40, TG 1.67 +/- 0.96, LDL-C 4.15 +/- 1.60, lipoprotein Lp(a) 0.19 +/- 0.25) apoB 0.95 +/- 0.32 and ERF ratio 5.46 +/- 2.24 were found in ID genotype, while in DD genotype HDL-C 1.11 +/- 0.28 and apo A-I 1.78 +/- 0.34 were lowest. In II genotype, the levels of apo A-II 0.56 +/- 0.11 were lowest and of apoE 0.09 +/- 0.05 highest. According to DD, ID and II genotypes and lipid, lipoprotein Lp(a), ERF ratio and apolipoprotein concentrations, there were no statistically significant differences between groups. ERF ratio in DD genotype showed a positive correlation with TG (r = 0.59) and LDL-C (r = 0.57), a slight positive correlation with apoB (r = 0.40), and a strong negative correlation with HDL-C (r = -0.73). ERF in ID genotype showed a strong negative correlation with HDL-C (r = -0.73), strong positive correlation with TG (r = 0.70), and T-C (r = 0.58), and slight positive correlation with LDL-C (r = 0.36) and alcohol abuse (r = 0.34). In II genotype, ERF ratio showed a strong positive correlation with LDL-C (r = 0.73), T-C (r = 0.70) and apoE (r = 0.58), slight positive correlation with apoB (r = 0.46) and TG (r = 0.36), and negative correlation with HDL-C (r = -0.54). Matrix correlation of DD genotypes showed the highest positive correlation between T-C and LDL-C (r = 0.91) and apoE (r = 0.45), and negative correlation between HDL-C and ERF ratio (r = 77), and LDL-C and ERF ratio (r = 0.55). In ID genotype, T-C showed a strong positive correlation between LDL-C (r = 0.75) and ERF ratio (r = 0.63), TG and ERF ratio (r = 0.73), and negative with HDL-C (r = 0.53). In genotype II, T-C showed a strong positive correlation between LDL-C (r = 0.96), ERF ratio (r = 0.71), apoB (r = 0.66) and apoE (r = 0.46). LDL-C correlated positively with ERF ratio (r = 0.72), apoB (r = 0.61) and apoE (r = 0.48). These findings indicated the frequency of ACE genotypes to differ within the group of menopausal women. Analysis of ACE genotypes showed ID genotype to be most common among menopausal women. This result indicated their intermediate risk of coronary heart disease (CHD) and myocardial infarction (MI). It has been well established that an increased risk of MI is associated with high frequency of DD genotype, and a low risk with high frequencies of II genotype. In addition to ACE polymorphism analysis, assessment of lipid, apolipoprotein, and lipoprotein Lp(a) concentrations, and of ERF ratio provides further important parameters for better understanding of the risk factors for CDH in women. In the present study, assessment of the genetic, metabolic and environmental markers pointed to an intermediate risk of CHD in menopausal women on HRT, although the mechanism underlying the disease is not clear and well understood yet.
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PMID:Angiotensin-converting enzyme gene polymorphism, lipids, and apolipoproteins in menopausal women on hormone replacement therapy. 1239 19

Normal ageing and Alzheimer's disease (AD) have many features in common and, in many respects, both conditions only differ by quantitative criteria. A variety of genetic, medical and environmental factors modulate the ageing-related processes leading the brain into the devastation of AD. In accordance with the concept that AD is a metabolic disease, these risk factors deteriorate the homeostasis of the Ca(2+)-energy-redox triangle and disrupt the cerebral reserve capacity under metabolic stress. The major genetic risk factors (APP and presenilin mutations, Down's syndrome, apolipoprotein E4) are associated with a compromise of the homeostatic triangle. The pathophysiological processes leading to this vulnerability remain elusive at present, while mitochondrial mutations can be plausibly integrated into the metabolic scenario. The metabolic leitmotif is particularly evident with medical risk factors which are associated with an impaired cerebral perfusion, such as cerebrovascular diseases including stroke, cardiovascular diseases, hypo- and hypertension. Traumatic brain injury represents another example due to the persistent metabolic stress following the acute event. Thyroid diseases have detrimental sequela for cerebral metabolism as well. Furthermore, major depression and presumably chronic stress endanger susceptible brain areas mediated by a host of hormonal imbalances, particularly the HPA-axis dysregulation. Sociocultural and lifestyle factors like education, physical activity, diet and smoking may also modulate the individual risk affecting both reserve capacity and vulnerability. The pathophysiological relevance of trace metals, including aluminum and iron, is highly controversial; at any rate, they may adversely affect cellular defences, antioxidant competence in particular. The relative contribution of these factors, however, is as individual as the pattern of the factors. In familial AD, the genetic factors clearly drive the sequence of events. A strong interaction of fat metabolism and apoE polymorphism is suggested by intercultural epidemiological findings. In cultures, less plagued by the 'blessings' of the 'cafeteria diet-sedentary' Western lifestyle, apoE4 appears to be not a risk factor for AD. This intriguing evidence suggests that, analogous to cardiovascular diseases, apoE4 requires a hyperlipidaemic lifestyle to manifest as AD risk factor. Overall, the etiology of AD is a key paradigm for a gene-environment interaction. Copyright 2000 John Wiley & Sons, Ltd.
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PMID:A unifying hypothesis of Alzheimer's disease. III. Risk factors. 1240 43

Lipoprotein (LP) metabolism plays a pivotal role in atherogenesis. Breakdown of triglyceride (TG) rich lipoproteins, both of exogenous--chylomicrones and endogenous--very low density lipoproteiny (VLDL) produces remnant lipoproteins after repeated action of lipoprotein lipase (LPL). Atherogenity of remnant lipoprotein has been proved. Also atheroprotective high density lipoproteins (HDL) are produced from surface of TG rich lipoproteins during their lipolysis. Protective role of HDL particles in atherogenesis is manifested by reverse cholesterol transport from all extrahepatic cells to the liver including cells of the arterial wall. Plasma concentration of atherogenic low density lipoproteins (LPL) is regulated by the production rate of VLDL in the liver on the one hand and their utilization by selective LDL receptors (mainly in the liver) on the other hand. Number of functioning LDL receptors is regulated genetically (gene for own LDL receptor and gene for both ligands--apoprotein B and apoprotein E) and also by environmental factors. Diet low in saturated fat and cholesterol and rich in dietary fibres increases number of LDL receptors and consequently decreases LDL cholesterol concentration. Monocytes entering arterial wall when intravasal and then subendothelial concentration of LDL is increased absorb LDL and predominantly oxidized LDL by scavenger receptors. During this repeated process they are changed to macrophages, residual macrophages and foam cells. Production of foam cells represents a starting point in atherogenesis but their high presence is typical also for advanced vulnerable atherosclerotic lesions, which are prone to rupture producing clinical complication--myocardial infarction and stroke.
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PMID:[Lipid metabolism in atherogenesis]. 1269 88


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