Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic defects of antithrombin (AT) or one of the components of the protein C pathway are associated with hereditary thrombophilia. Laboratory assays are currently available to diagnose and type hereditary thrombophilia due to deficiency or dysfunction of one of the anticoagulant factors antithrombin (AT), protein C (PC) and protein S (PS), and APC resistance without the need of DNA analysis. There are no functional tests for the prothrombin mutant G20210A and thrombomodulin mutations, which can be diagnosed by a PCR-based test or by gene analysis, respectively. Hereditary AT deficiency is classified in a quantitative type I and three functional type II deficiencies affecting the reactive site (RS), heparin binding site (HBS), or pleiomorphic site of the AT protein. All four types of hereditary AT deficiencies can be diagnosed by a heparin cofactor assay and one immune assay in combination with crossed immunoelectrophoresis of the AT protein. The combination of an enzyme-linked immunoadsorbent assay (ELISA) and a functional Protac-APTT-based assay for PC will detect quantitative type I and dysfunctional type II PC deficiencies. There is a significant overlap in PC antigen and functional levels between heterozygotes of PC deficiency and normals leaving a gray zone of uncertainty in differentiating congenital PC deficiency and normal individuals. Accurate diagnosis of hereditary PS deficiency should be a combination of tests aimed to measure free PS activity and antigen and total PS antigen levels. APTT-, Xa-, and RVVT-based APC-resistance tests, when test plasmas are diluted in factor V deficient plasma, have increased in sensitivity and specificity to 100% for the discrimination of normal individuals from heterozygotes and homozygotes for factor V Leiden. The RVVT-based APC-resistance test provides better separation of factor V Leiden and normals in the various clinical settings, lupus anticoagulant in particular. The modified APC-resistance tests also claim a separation between heterozygotes and homozygotes for factor V Leiden in the normal population, asymptomatic subjects, and thrombosis patients. Below a certain cut-off level, a minor overlap of normalized APC ratios between heterozygotes and homozygotes for factor V Leiden of thrombosis patients has been shown in one study, which still points to the need to perform the more time consuming and expensive DNA test to identify heterozygotes from the more clinically significant homozygotes. The prothrombin-based APC-resistance test, which measures thrombin activated factor Va in highly diluted test plasma, appears to be the most sensitive and specific of all APC-resistance tests and separates normal individuals from heterozygotes and heterozygotes from homozygotes for factor V Leiden without the need of confirmation by a DNA test.
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PMID:Laboratory diagnosis of hereditary thrombophilia. 976 48

Endothelial cells form a multifunctional cell lining that covers all of the inner surface of blood vessels and regulates several important physiological and pathological reactions. These include inflammation/immune reaction, blood vessel tonus, hemostasis/thrombosis, angiogenesis and so on. Thus, abnormalities of endothelial function may play crucial roles in the development of angitis syndrome, thrombosis/embolism, bleeding disseminated intravascular coagulation (DIC), and neovascularization in some pathological states including tumor growth and diabetic retinopathy. Research on endothelial cells now forms a new frontier termed 'Endotheliology'. Recent advances of the functional and structural aspects of endothelial cells are reviewed here mainly from the viewpoint of endothelial regulation of coagulation and the fibrinolytic system. First we show that the natural endothelial membrane protein thrombomodulin is localized not only on apical endothelial surface but also in caveolae. Since it has been reported that such factors involved in coagulation/fibrinolysis as tissue factor, tissue factor pathway inhibitor (TFPI), thrombin receptor and urokinase receptor are also localized in the caveolae, this membrane structure may act as a special component to regulate coagulation/fibrinolysis on the endothelial membrane surface. Next we demonstrate the signaling pathway of the thrombin receptor. Thrombin cleaves the N-terminus of the receptor as a substrate, exposing a new N-terminus. This newly exposed N-terminus acts as a ligand and activates platelets, endothelial cells and vascular smooth-muscle cells. We have identified that the signal from the thrombin receptor activates NF-kappaB through the activation of protein C kinase, tyrosine kinase and MAP kinase, and results in proliferation of the cells. We have also shown that the receptor is over-expressed on platelets from diabetes patients.
Lupus 1998
PMID:Biology of endothelium. 981 71

Thrombomodulin (TM), a high affinity thrombin receptor present on endothelial cell membrane, plays an important role as a natural anticoagulant. It acts as a cofactor of thrombin-catalyzed activation of protein C, and inhibits the procoagulant functions of thrombin. TM is also located in other cells (keratinocytes, osteoblasts, macrophages,...) where it might be involved in cell differentiation or in inflammation. In the presence of cytokines, activated neutrophils and macrophages, endothelial TM is cleaved enzymatically, releasing soluble fragments which circulate in the blood and are eliminated in urine. Plasma TM level (pTM) can be measured using a two-site enzyme-linked immunosorbent assay (ELISA). pTM level is regarded as a molecular marker reflecting injury of endothelial cells. It is often increased in case of diffuse endothelial damage as in disseminated intravascular coagulation, diabetic microangiopathy, Plasmodium falciparum and rickettsial infections. pTM is also a predictive marker of hypertensive complications in pregnancy. In several systemic inflammatory diseases, pTM levels are correlated to the activity of the disease.
Lupus 1998
PMID:Thrombomodulin: an overview and potential implications in vascular disorders. 981 88

The protein C pathway plays a critical role in the negative regulation of the blood clotting process. We recently identified an endothelial cell receptor for protein C/activated protein C (APC). The receptor is localized almost exclusively on endothelial cells of large vessels and is present at only trace levels or indeed absent from capillaries in most tissues. Patients with sepsis or lupus erythematosus exhibit elevated levels of plasma EPCR which migrates on gels as a single band and is fully capable of binding protein C/APC. There is no correlation with thrombomodulin levels, probably due to different vascular localizations and/or cellular release mechanisms. To understand the mechanisms by which EPCR plasma levels are elevated, we examined EPCR mRNA expression in a rat endotoxin shock model. The EPCR mRNA gene exhibited an early immediate gene response to endotoxin with the mRNA levels increasing nearly 4 fold in the first 3-6 hrs, before returning toward baseline. Plasma levels of EPCR also rose about 4 fold with little change in tissue EPCR levels. Both processes were markedly attenuated by hirudin suggesting that thrombin was responsible for increases in mRNA and plasma EPCR levels. At the level of mRNA, the induction is mediated by a thrombin response element in the 5' flanking region of the gene. Direct thrombin infusion and cell culture experiments support this contention. On endothelium, thrombin is capable of releasing cell surface EPCR and this process is blocked by the metalloproteinase inhibitor orthophenanthroline. Taken together these studies indicate that elevation in soluble plasma EPCR reflects endothelial cell activation in the larger vessels and is likely to be an indication of local thrombin generation near these vessel surfaces.
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PMID:Regulation and functions of the protein C anticoagulant pathway. 1019 Sep 52

By virtue of a severely prolonged aPTT with a normal thromboplastin time (prothrombin time) and a normal thrombin time, severe FXII deficiency has been diagnosed in a woman without a bleeding diathesis or a history of thromboembolic complications. A deficiency of a factor of the contact activation system (FXII, prekallikrein, high molecular weight kininogen) is usually diagnosed during routine coagulation tests demonstrating a prolonged aPTT. The severe and partial deficiency of FXII, of prekallikrein or high molecular weight kininogen is not associated with a bleeding tendency. In contrast, severely factor XI deficient subjects may suffer from a mild hemorrhagic diathesis, whereas FVIII deficiency (hemophilia A, autoimmune "hemophilia", von Willebrand disease) and FIX deficiency (hemophilia B) are associated with a bleeding tendency of varying severity, depending on the clotting activity of FVIII or FIX, respectively. An isolated prolongation of the aPTT due to a lupus anticoagulant, however, is frequently associated with arterial and/or venous thrombosis. Therefore, in case of a prolongation of the aPTT, its cause has to be determined.
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PMID:[A patient with isolated prolongation of aPTT without hemorrhagic diathesis anamnesis: severe, hereditary factor XII deficiency]. 1051 21

Lupus anticoagulants (LA) are a family of autoantibodies that are associated with in vitro anticoagulant activity but a strong predisposition to in vivo thrombosis. They are directed against plasma phospholipid binding proteins, including prothrombin. We found that a murine monoclonal antiprothrombin antibody and 7 of 7 LA IgGs tested enhanced binding of prothrombin to 25:75 phosphatidyl serine:phosphatidyl choline vesicles in a concentration-dependent manner. We hypothesized that enhanced binding of prothrombin to phospholipid in the presence of LA IgG might result in increased thrombin production when reactions are performed in flow. Thrombin production by purified prothrombinase components was measured in a phospholipid-coated flow reactor. The flow reactor was incubated with prothrombin, calcium ions, and the IgGs and then perfused with prothrombin, calcium ions, the IgGs, factor Va, and factor Xa. A murine monoclonal antiprothrombin antibody and 4 of 6 LA IgGs from patients with a history of thrombosis increased thrombin production up to 100% over control in the first 15 minutes. In summary, LA IgGs concentrate prothrombin on a phospholipid surface that can augment thrombin production by prothrombinase in flow. These observations suggest that LA might propagate coagulation in flowing blood by facilitating prothrombin interaction with the damaged blood vessel wall.
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PMID:Lupus anticoagulants form immune complexes with prothrombin and phospholipid that can augment thrombin production in flow. 1055 52

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder with overwhelming thrombotic states. The precise pathogenetic mechanisms underlying the prethrombotic state in SLE is not fully understood, but interactions between the antiphospholipid antibodies and antigen targets on the coagulation components have been incriminated to play fundamental roles. To evaluate this issue, 34 women with antiphospholipid antibody negative SLE were investigated for molecular markers of blood coagulation and fibrinolytic activity: prothrombin fragment1+2 (PF1+2), thrombin-antithrombin complex (TAT), plasmin-alpha2-antiplasmin inhibitor complex (PAP), and tissue factor pathway inhibitor (TFPI). We also analysed plasma soluble thrombomodulin (sTM) levels. SLE disease activity was determined using the SLE Disease Activity Index (SLEDAI). Concentrations of TAT, PAP, PF1+2 and sTM were significantly elevated (P<0.0001, P=0.0002, P<0.0001, and P<0.0001, respectively), while TFPI antigen levels were found to be reduced (P<0.0001) in patients with SLE compared to the control group. In patients with active SLE, anti-ds DNA levels were correlated positively with plasma TAT (P<0.05), PF1+2 (P<0.05), and sTM (P<0.01) concentrations and negatively with plasma TFPI levels (P<0.05). SLEDAI scores were correlated positively with plasma TAT (P<0.01), PF1+2 (<0.01), and sTM (P<0.01) levels. This study illustrates that both a prethrombotic state and a compensatory fibrinolytic process secondary to subclinical intravascular coagulation might coexist in SLE with elevated sTM levels, indicating impaired endothelial functions.
Lupus 1999
PMID:Clinical significance of hemostatic markers and thrombomodulin in systemic lupus erythematosus: evidence for a prothrombotic state. 1060 46

Autoantibodies against prothrombin, including lupus anticoagulant antibodies (LAC), have been identified in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). To identify the epitopes of LAC in patients with SLE and APS, we analyzed B cell epitopes of anti-prothrombin Abs. Prothrombin was purified from fresh plasma samples from healthy subjects, and fragmented by thrombin. Two fragments (prethrombin-1, 50 kDa, and fragment-1, 22 kDa) were separated and used for further experiments. The two fragments were coated on irradiated plate and the binding activities of sera from 13 patients with anti-prothrombin Abs (SLE, 7; APS, 4; SLE+APS, 2) were determined by using ELISA. The assay was conducted under the following conditions: use of irradiated plates, and TBS containing Tween-20. We detected two types of anti-prothrombin Abs. The first was anti-prethrombin-1 (n=5) while the other was Ab against fragment-1 (n=8). There were no patients with Abs that showed binding activities to both fragments. A higher proportion of patients with thrombosis were positive for anti-prethrombin-1 Abs (80%) than for anti-fragment-1 Abs (25%). Two patients with anti-prethrombin-1 Ab were positive for LAC and negative for anti-cardiolipin-beta2 glycoprotein I antibody (aCL-beta2GPI). Our results strongly support the notion that both prethrombin-1 and fragment-1 on prothrombin molecule are B cell epitopes.
Lupus 1999
PMID:Relationship between clinical features and binding domains of anti-prothrombin autoantibodies in patients with systemic lupus erythematosus and antiphospholipid syndrome. 1060 50

A 26-year-old female presented with an episode of severe mucus membrane bleeding. Investigations revealed prolonged prothrombin time (PT), and partial thromboplastin time (PTT), normal thrombin time (TT) and reptilase time, thrombocytopenia, a positive test for lupus anticoagulant (LA), as well as anti-cardiolipin antibodies (ACL). A toxicology screen for toxic drugs and coumadin was negative. Coagulation factor assays revealed low levels for factor II and XII. Low level inhibitor to factor II was demonstrated. Patient had a negative VDRL test and positive anti-nuclear antibodies (ANA). The diagnosis of acquired hypoprothrombinaemia secondary to circulating inhibitor induced by LA was made, and then the patient was started on prednisone, which led to cessation of the bleeding and normalization of PT and PTT, as well as an increase of factor II and factor XII levels. A few months later, the patient developed arthralgia and alopecia, and antibodies against double-stranded DNA were detected, and the diagnosis of systemic lupus erythematosis (SLE) was confirmed. The patient continued to have mild prolongation of PT and PTT while on a low dose of prednisone, but she had no bleeding symptoms. A computed tomography scan of the brain was carried out for unexplained central nervous system (CNS) symptoms, and it revealed mild hydrocephalus, which was thought to be part of the CNS manifestations of SLE. It was concluded that patients with SLE may present with haemostatic defects that are a result of either platelet-related causes (quantitative or qualitative) or coagulation factor deficiency secondary to circulating inhibitor, or both, in the absence of other features of SLE which may appear later.
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PMID:Systemic lupus erythematosus presenting with haemorrhagic manifestation. 1067 97

We reported an autopsy case of cerebral infarction with primary lung cancer. The patient was a 50-year-old man. Despite having been treated with warfarin potassium and ticlopidine hydrochloride, he relapsed cerebral infarction. His laboratory data on admission showed that lupus anticoagulant was positive, together with a high value of beta-thromboglobulin, thrombin-antithrombin III complex, markers of platelet and coagulation activation, CEA and CA 19-9. The autopsy finding revealed a primary papillary adenocarcinoma in the right lower lung, multiple cerebral infarction, renal infarction, pulmonary infarction and splenic infarction. The atherosclerotic changes were mild in the whole tissues and findings of vasculitis were not observed. Recurrence of cerebral infarction was effectively suppressed with the addition of steroid therapy to antithrombotic therapy. This case was considered as catastrophic antiphospholipid syndrome. It is necessary to differentiate antiphospholipid syndrome in case of the abnormal coagulation and fibrinolytic factors with recurrent cerebral infarction. Moreover, systemic examinations are important, because malignant tumor may exist on the background of the case.
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PMID:[An autopsy case of catastrophic antiphospholipid syndrome presenting with recurrent multiple cerebral infarction associated with lung cancer]. 1068 94


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