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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypercoagulable states are disorders of blood coagulation, which include deficiencies of natural anticoagulants, disorders of the fibrinolytic system, presence of antiphospholipid antibody and abnormalities of platelet function. These disorders are well known causes of venous thromboembolic disease and are being recognized in association with arterial thromboembolic occurrences with increasing frequency. The performance of standard prosthetic vascular reconstructions may result in disastrous outcomes in patients with unrecognized and untreated hypercoagulable states. From 1986 to 1990, we identified 12 patients with hypercoagulable states, six of whom presented with evidence of arterial thromboembolism. All of the patients were men who smoked and were somewhat younger than the usual patient with atherosclerosis. Their ages ranged from 41 to 62 years. Four patients presented with ischemic rest pain, one patient with blue toe syndrome and one with rapidly progressive claudication. Four patients had undergone prior vascular reconstruction and two had previous pulmonary emboli. Evaluation of these patients to identify hypercoagulability included determinations of prothrombin time (PT) and partial thromboplastin time (PTT), platelet count, antithrombin III, protein C, free protein S and total protein S levels, along with platelet aggregometry. Two patients had protein S deficiency, one had protein C deficiency, one patient had protein C and S deficiency and two patients had hyperaggregable platelets. Four patients had prosthetic reconstructions and two had autogenous reconstructions. Three of the four patients undergoing prosthetic reconstructions had subsequent loss of limb and one patient died. Only one patient with prosthetic reconstruction had a patent graft on long term anticoagulation. Both patients undergoing autogenous procedures had successful revascularization with limb salvage.
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PMID:Hypercoagulable states in arterial thromboembolism. 154 37

Previous results, presented in abstract form, indicate that replacement of thromboplastin with a mixture of phospholipid and truncated soluble tissue factor apoprotein results in a coagulation assay that can directly measure plasma factor VIIa levels without interference from zymogen factor VII (Atherosclerosis Thromb 11:1544a, 1991 [abstr]). We have exploited the specificity and sensitivity of such a factor VIIa specific coagulation assay to directly assess the in vivo relationship of factor VIII and factor IX on the production of factor VIIa levels under nonthrombotic and nonstimulatory conditions. Normal individuals (n = 20) were found to possess an average circulating factor VIIa level corresponding to 4.34 +/- 1.57 ng/mL, or approximately 1% of their total factor VII antigen. Severe factor VIII deficient patients (n = 13) possessed a slightly lower but statistically significant (P less than .01) decrease in their basal factor VIIa levels (2.69 +/- 1.52 ng/mL), corresponding to approximately 60% of that observed in normal individuals. On the other hand, severe factor IX deficient patients (n = 7) were found to possess even lower levels of factor VIIa corresponding to 0.33 +/- 0.15 ng/mL, or less than 10% of that observed in normal individuals. Measurement of total factor VII antigen levels shows that the variation in basal factor VIIa levels stems from differences in the degree of factor VII activation as opposed to differences in factor VII antigen levels. Our present data are consistent with the hypothesis that factor IXa is the principal in vivo activator of factor VII under basal conditions.
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PMID:Measurement of basal levels of factor VIIa in hemophilia A and B patients. 146 30

The antiphospholipid syndrome was diagnosed in 19 of 1078 patients treated between 1987 and 1991. All patients with antiphospholipid syndrome had either anticardiolipin antibody (16/19) or lupus anticoagulant (10/19); three patients had thrombocytopenia, eight patients had a prolonged partial thromboplastin time, and 10 patients had an elevated erythrocyte sedimentation rate. The most common site of involvement was the cerebral circulation (nine patients), manifested by transient ischemic attacks or stroke. Eight patients had upper extremity disease, characterized by symptoms of Raynaud's phenomenon, with angiographic lesions involving the brachial, radial, ulnar, and/or digital arteries. Lower extremity disease occurred in seven patients, with clinical presentations similar to those of atherosclerosis and varying angiographic patterns. In comparison with the population having atherosclerosis, patients with arterial manifestations of antiphospholipid syndrome were more likely to be women (13 of 19 versus 411 of 1078, p less than 0.02), were significantly younger (46.2 years versus 63.6 years, p less than 0.0001), did not smoke (1 of 19 patients versus 700 of 1078, p less than 0.0001), had a higher percentage of upper extremity involvement (8 of 18 versus 13 of 1078, p less than 0.0001), and had a higher incidence of early graft failure (9 of 12 grafts versus 13 of 371 grafts, p less than 0.0001). The syndrome is associated with the repetitive failure of vascular reconstructions and occlusion of native vessels. Antiphospholipid syndrome should therefore be suspected in young, female, nonsmokers with vascular disease, especially those with involvement of the upper extremity, cerebrovascular disease with normal findings on extracranial carotid angiography, and premature graft failure.
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PMID:Vascular disease in the antiphospholipid syndrome: a comparison with the patient population with atherosclerosis. 172 74

A 44-year-old woman with a history of cerebral infarction and hypertension developed sudden onset of speech and visual disturbance. On admission, her general physical examinations showed high blood pressure of 210/120 mmHg and Raynaud's phenomena. The neurological examinations revealed right upper quadratic hemianopsia, left oculomotor nerve paresis and left hyperreflexia. Laboratory findings showed that antinuclear and anti-DNA antibodies were positive. The activity of Fletcher factor was reduced to 50%, and the activated partial thromboplastin time (APTT) was prolonged to 82.6 seconds. And a 1:1 dilution with normal plasma failed to correct the prolonged APTT, indicative of circulating anticoagulant to Fletcher factor. Plasma fibrinogen increased to 500 mg/dl but FDP was normal. The CT scan demonstrated the recurrently developed cerebral infarction in the left occipital lobe. Cerebral angiogram revealed mild atherosclerosis of basilar and bilateral posterior cerebral arteries, but any occlusive lesions were not found. Although she had a history of hypertension, this case suggests the possibility that the disturbance in fibrinolytic system may have been caused by the circulating anticoagulant to Fletcher factor, and contributed to her cerebral infarctions.
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PMID:[A case of cerebral infarction with circulating anticoagulant to Fletcher factor]. 191 33

Latent infection of vascular cells with herpes-viruses may play a pathogenic role in the development of human atherosclerosis. In a previous study, we found that cultured human umbilical vein endothelial cells (HUVECs) infected with herpes simplex virus 1 (HSV-1) became procoagulant, exemplified both by their enhanced assembly of the prothrombinase complex and by their inability to reduce adhesion of platelets. We now report two further procoagulant consequences of endothelial HSV infection: loss of surface thrombomodulin (TM) activity and induction of synthesis of tissue factor. Within 4 hr of infection of HUVECs, TM activity measured by thrombin-dependent protein C activation declined 21 +/- 3% (P less than 0.05) and by 18 hr, 48 +/- 5% (P less than 0.001). Similar significant TM decrements accompanied infection of bovine aortic endothelial cells. Identical TM loss was induced with HSV-2 infection but not with adenovirus infection. Decreased surface expression of TM antigen (measured by the specific binding of a polyclonal antibody to bovine TM) closely paralleled the loss of TM activity. As examined by Northern blotting, these losses apparently reflected rapid onset (within 4 hr of HSV infection) loss of mRNA for TM. In contrast, HSV infection induced a viral-dose-dependent increase in synthesis of tissue factor protein, adding to the procoagulant state. The results indicate that loss of endothelial protein-synthetic capacity is not a universal effect of HSV infection. We suggest that the procoagulant state induced by reduction in TM activity and amplified tissue factor activity accompanying HSV infection of endothelium could contribute to deposition of thrombi on atherosclerotic plaques and to the "coagulant-necrosis" state that characterizes HSV-infected mucocutaneous lesions.
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PMID:Infection of vascular endothelial cells with herpes simplex virus enhances tissue factor activity and reduces thrombomodulin expression. 216 19

In a strictly controlled cross-over study (twice 2 weeks) of 11 healthy adults, the effects of a low-fat diet (32% of total energy from fat) with a low or a high ratio of polyunsaturated to saturated fatty acids (0.28 and 0.89, respectively) were observed. Factor VII activity and antigen levels, serum cholesterol, HDL-cholesterol and triglycerides were measured. Factor VII activity was determined in clotting assays using human and bovine thromboplastin (interacting primarily with activated factor VII, F VIIa), allowing differentiation between F VIIc and F VIIa. A significant decrease of F VII levels (median 11.0-14.5%, P less than 0.05) and triglycerides (median 0.22-0.27 mmol/l, P less than 0.05) was observed on both diets, while only the highly unsaturated diet reduced serum cholesterol levels (median 0.65 mmol/l, P less than 0.001). There were no significant correlations between changes in blood lipids and F VIIc. Low fat diets may reduce the risk for ischemic heart disease without lowering of cholesterol levels by eliminating states of hypercoagulability such as elevated factor VII coagulant activity.
Atherosclerosis 1990 Jan
PMID:Effects of total fat content and fatty acid composition in diet on factor VII coagulant activity and blood lipids. 231 Apr 28

Monocytes and endothelial cell interactions play a key role in the development of vascular lesion, inflammation and atherosclerosis. Leukocyte adhesion is mediated through specific molecules CD11/CD18 complexes on the leukocyte side and the ELAM (Leukocyte Adhesion Molecule) ICAM (Intercellular Adhesion Molecule) on the endothelium cell surface. Several monocyte products damage endothelial cells such as free radicals, oxygen peroxides, proteases, hydrolases, lipases... Various monokines alter endothelial cell function and proliferation. Interleukin 1, gamma interferon, alpha tumor necrosis factor increase ELAM, further more they induce the synthesis of procoagulant activity by endothelial cells. Monocyte derived growth factor stimulates endothelial cells proliferation while transforming growth factors, beta (TGF beta) and TNF alpha inhibit endothelial cell growth. Lipid products of monocyte origins such as leukotrienes induce an activation of endothelial cells which results in a production of prostacyclin. Monocytes may also participate in the coagulation process by producing thromboplastin and coagulation factors and facilitating the tenase (activation of factor X) complex formation. On the other hand, monocyte also synthesize tissue plasminogen activator and inhibitor. The numerous factor produced by monocytes may affect in different ways the endothelial cell behavior.
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PMID:[Monocyte-endothelium relations]. 265 10

In cultured human monocytes/macrophages, surface expression of procoagulatory activity (PCA) was induced by chemically modified LDL (acetyl-LDL and MDA-LDL) in a dose- and time-dependent manner. Maximum PCA (30-fold increase) was detected after 24 h of culture with modified LDL at doses of 25-750 micrograms protein/ml. Using factor VII deficient human plasma and phospholipase C this PCA was identified as tissue thromboplastin activity (factor III). These results suggest a further atherogenic potential for modified LDL through stimulation of the conversion of fibrinogen to fibrin in the atheromatous lesion.
Atherosclerosis 1989 Aug
PMID:Enhanced procoagulatory activity (PCA) of human monocytes/macrophages after in vitro stimulation with chemically modified LDL. 278 95

A remarkable variation in monocyte activation among individuals was observed when blood from different people was incubated with lipopolysaccharides. To elucidate this phenomenon, we studied intracellular signals associated with monocyte activation. This was done by measuring induced thromboplastin synthesis. An inhibitor of phospholipase A2 blocked the lipopolysaccharide induced synthesis of thromboplastin. Thus, release of arachidonic acid (20: 4) seemed to be necessary to activate the monocytes. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, had no effect on the monocyte activation in subjects with a low response to lipopolysaccharides (low responders); this contrasted with nearly 80% inhibition in individuals with very sensitive cells (high responders). Taking aspirin raised monocyte activation by an average of 50%, this was caused by the effect of aspirin on the platelets. Platelets enhanced the lipopolysaccharide activation of monocytes 2-3 fold. The high response phenomenon was partially due to platelets. When platelets in the blood of high responders were substituted with platelets from low responders, the monocyte activation fell by up to 70%. Fatty acids seemed to play a central role in the activation of monocytes. Intake of cod liver resulted in significant reduction of induced thromboplastin synthesis. It is suggested that those who are high responders may be more susceptible to developing atherosclerosis.
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PMID:Fatty acids, platelets and monocytes. Something to do with atherogenesis. 292 3

Restenosis after angioplasty is probably related to 2 processes: thrombosis and recurrence of atherosclerosis. Many approaches to altering these processes are available, but to date none has shown a high rate of success. Heparin has properties relevant to both processes; this makes it an attractive compound for further study. The anticoagulant action of heparin is well known. It is mediated primarily though complex formation with antithrombin III, which leads to a conformational change and an increased rate of thrombin inactivation. Heparin has additional antithrombotic actions, largely mediated through the formation of the same complex, but involving precursor elements such as factor Xa. These actions of heparin can be localized to different portions of the large, complex molecule. Additionally, experimental studies have demonstrated an antiproliferative action of heparin, a property that may be relevant to smooth muscle cell proliferation after angioplasty. This is mediated by a fairly small, functionally distinct nonanticoagulant portion of the heparin molecule. Fragments of heparin possessing particular actions are being investigated experimentally and clinically. Continued investigations of the structure and function of heparin promise to lead to a decreased rate of restenosis and a better understanding of the mechanisms of angioplasty.
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PMID:Anticoagulation and restenosis after percutaneous transluminal coronary angioplasty. 295 35


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