Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The term 'antiphospholipids' (APL) refers to heterogeneous auto-antibodies, including anticardiolipins detected by immunological methods and lupus anticoagulants detected by clotting tests. APL are currently of considerable interest, both from a clinical and a biological point of view, since their presence is associated with thromboembolic events. In this review, the authors emphasize the diversity of the clinical settings where APL are diagnosed and investigate the relationship between APL and thrombosis. The heterogeneity of APL and the lack of standard techniques make their laboratory diagnosis difficult and require the use of various types of tests. Several pathogenic mechanisms, all related to a possible effect of APL on the antithrombotic functions of vascular endothelium, have been proposed: decrease in prostacyclin synthesis, induction of procoagulant activity, inhibition of the endothelial anticoagulant functions, and impairment of fibrinolysis. Given the heterogeneity of these antibodies, it is unlikely that a single mechanism can account for their prothrombotic effect.
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PMID:[Antiphospholipid antibodies]. 780 45

Antiphospholipid antibodies are a diverse group of immunoglobulins initially thought to have specificity to phospholipid epitopes. It is apparent that autoimmune anticardiolipin antibodies require a serum cofactor beta-2-glycoprotein I (beta 2GPI) for their binding to phospholipids. Lupus anticoagulant also may bind to phospholipids by beta 2GPI or by prothrombin. The description of binding to protein-phospholipid epitopes may explain several perplexing features of these antibodies both in vitro and in vivo. Antiphospholipid antibodies have a well-established association with clinical disease--in particular thrombosis, thrombocytopenia and recurrent fetal loss. The mechanism of the predisposition to thrombosis seen with these antibodies is poorly understood. It has been suggested that they may cause endothelial dysfunction by causing increased tissue factor expression, by inhibiting prostacyclin secretion or by inhibiting fibrinolysis. Various platelet-activating activities have also been described. The evidence that antiphospholipid antibodies promote thrombosis by effects on endothelium or platelets is inconclusive. Inhibition of protein C activation, or of activated protein C action, has been demonstrated in vitro. A poor correlation between thrombosis in vivo and these inhibitory effects has been found. Beta-2-glycoprotein I has been identified as a cofactor for binding to phospholipid by thrombogenic anticardiolipin antibodies. That beta 2GPI may be a natural anticoagulant of importance remains to be proved. Inhibition by antiphospholipid antibodies of this anticoagulant function could explain the propensity to thrombosis seen in association with these antibodies.
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PMID:Antiphospholipid antibodies and thrombosis. 784

In a group of 6 patients with lupus anticoagulant (LA) and antiphospholipid (aPL) antibodies detected by ELISA overnight urine and blood were simultaneously collected. A significantly increased urinary excretion of the platelet-derived thromboxane (TX) metabolite 11-dehydro-TXB2 was found in this group, as compared to 12 healthy individuals. In contrast, a small but significant reduction of the vascular prostacyclin (PGI2) metabolite 2,3-dinor-6-keto-prostaglandin F1 alpha was observed. To further elucidate the effect of these antibodies on platelet activation we isolated the F(ab')2 fragments from IgG of the 6 patients and 5 controls, and we evaluated the effect of these fragments on the responses of isolated normal platelets to thrombin. Patients' F(ab')2 increased platelet aggregation and serotonin release of platelets stimulated by low dose thrombin (0.01 U/ml). At threshold thrombin concentration (0.05 U/ml) an enhanced TXB2 production was also observed. In summary, our results show, in addition to the altered TXA2/PGI2 balance observed in vivo, a direct stimulatory effect of aPL antibodies on platelet activation in vitro. This effect is related to recognition of phospholipid epitopes on platelets as shown by its neutralization upon preincubation with phospholipids. This phenomenon may be relevant for the thrombotic tendency of these patients.
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PMID:Antiphospholipid antibodies enhance thrombin-induced platelet activation and thromboxane formation. 811 93

IgG from 18 patients with SLE, eight with the primary antiphospholipid syndrome and 19 controls was examined for its effect on thrombin-induced prostacyclin (PGI2) release from human umbilical vein endothelial cells in relation to both the titre of anticardiolipin (ACA) and antiendothelial activity (AEA) and clinical thrombotic events. Although no significant inhibition of PGI2 release was found overall, examination of subgroups revealed that IgG from patients with ACA produced significant inhibition of PGI2 release (mean stimulation index IgGM, 0.74 +/- 0.12, P = 0.02) when compared with patients without ACA (1.18 +/- 0.12). Further analysis revealed a significant positive correlation between ACA and AEA (r = 0.52, P = 0.006) in the total patient group which was reflected in significant negative correlations between inhibition of PGI2 release and increasing titre of both ACA (r = -0.42, P = 0.032) and AEA (r = -0.57, P = 0.002). However, only increasing titre of AEA showed a significant negative correlation with inhibition of PGI2 release when patients with (r = -0.74, P = 0.0005) and without (r = 0.23, N.S.) thromboses were compared. The titre of ACA failed to show any significant correlation with inhibition of PGI2 release in either patients with (r = -0.42, N.S.) or without (r = -0.16, N.S.) thromboses. These findings suggest that previous, sometimes conflicting, reports of an association between inhibition of PGI2 release and ACA may be explained by the co-incidence of AEA with ACA.
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PMID:Inhibition of prostacyclin release by endothelial binding anticardiolipin antibodies in thrombosis-prone patients with systemic lupus erythematosus and the antiphospholipid syndrome. 816 51

Infertility is defined as a reproductive disorder in which pregnancy is established, but normal fetal growth can never be achieved due to pregnancy loss. The pathogenesis of this disorder must be understood accurately to obtain optimal results in its management. Although genetic, anatomic and hormonal factors have been implicated as to its cause, a substantial proportion of cases remain unexplained. Recently, an immunologic etiology for this disorder has been proposed for many couples with infertility due to unexplained causes. Author has evaluated patients with infertility according to two immunologic aspects, namely "autoimmune" and "alloimmune", and assessed them pathophysiologically and clinically. [Autoimmune abnormality] Autoimmune diseases, especially SLE, have been associated with pregnancy loss, with autoantibody abnormalities being speculated to be causally related to this reproductive disorder. Especially among various autoantibodies, author noticed an antiphospholipid antibody (aPL) that has been associated with micro-thrombosis, and performed the enzyme-linked immunosorbent assay. Pathophysiological evaluations performed were as follows: 1. Inhibitory effect of aPL on prostacyclin production in cultured vascular endothelial cells. 2. Existence of aPL in the elute from placental tissue. Clinical evaluations were as follows: 1. Frequency of aPL positivity among patients with infertility. 2. Correlation between frequency of aPL positivity at the placental site and the outcome of pregnancy. 3. Correlation between the selected modes of medical therapy (e.g., administration of prednisolone, aspirin, etc.) in aPL-positive cases and the outcome of pregnancy. Based on the results of the above evaluations, it was suggested that IgG-aPL can be considered a useful diagnostic and prognostic variable in women with infertility. Moreover, it was considered that the inhibition of prostacyclin production due to aPL might disturb utero-placental circulation by vasoconstriction and local vascular thrombosis in the placenta and thus lead to pregnancy loss. It was confirmed that the combination of immunosuppressive and anticoagulant therapy is, to a certain extent, an effective treatment for aPL-positive pregnant women. [Alloimmune abnormality] When normal pregnancy is viewed from an immunological standpoint, there arises a basic question of how the fetus escapes immunological rejection despite being allograft. Explanations have been based on various mechanisms of maternal immunity and some experiments were therefore attempted to elucidate the immunological mechanisms. Points of evaluation were as follows: 1. Blocking activity of serum utilizing the mixed lymphocyte reaction with lymphocytes of the husband as stimulators and those of the wife as responders. 2. Detection of HLA-class II antibody, cold-B cell antibody, and anti-idiotype antibody as blocking antibodies in the serum.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Pathogenesis on infertility; its immunological aspects]. 837 Oct 5

Connective tissue diseases (CTDs) frequently present with one or only a few symptoms, which does not allow prompt diagnosis. Raynaud's phenomenon is one of those symptoms. However, only a minority of patients who present with Raynaud's phenomenon develop a CTD. Prognostic factors for the future development of CTD in such patients are older age at presentation, more severe Raynaud's phenomenon, the presence of antinuclear antibodies, and abnormal patterns on nailfold capillary microscopy. Some patients have overlapping symptoms of various CTDs. Mixed connective tissue disease (MCTD) is the prototype of such an overlapping syndrome. However, during follow-up, most patients with MCTD develop a specific CTD, either scleroderma, systemic lupus erythematosus, rheumatoid arthritis, or combinations of those illnesses. Primary pulmonary hypertension is one of the leading causes of death in MCTD. Its treatment is insufficient, although continuous prostacyclin infusion may provide some relief. New therapies such as nitric oxide and combined heart-lung transplantation in an early stage should be explored. The autoimmune response to small nuclear ribonucleoproteins, which is highly characteristic for MCTD, interestingly shows cross-reactivity with retroviral antigens, and the cooccurrence of human T cell lymphotropic virus type I and HIV infection with MCTD has been reported. This suggests that those viruses, possibly by molecular mimicry, play a role in the induction of the disease. Fibrotic conditions related to silicone exposure still evoke much interest. However, most recent data do not substantiate a role for silicone gel breast implants in the development of autoimmune CTDs.
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PMID:Overlapping syndromes, undifferentiated connective tissue disease, and other fibrosing conditions. 857 80

A 24-year-old woman was admitted to our hospital because of pulmonary hypertension. Five years earlier, she had been given a diagnosis of systemic lupus erythematosus. The pulmonary hypertension was believed to have been caused by pulmonary vasculitis, because pulmonary angiography, nuclear perfusion scans, and axial magnetic resonance imaging of the pulmonary artery showed no evidence of pulmonary thromboembolism. Steroids, a calcium antagonist, and home oxygen therapy did not reduce the patient's pulmonary hypertension. The level of thromboxane B2, a stable metabolite of thromboxane A2, in the pulmonary artery was abnormally high (140 pg/ml). This suggested that vasoconstriction of the pulmonary artery and microthrombosis would cause continuous pulmonary hypertension. Beraprost sodium (120 micrograms/day, p.o.) was administered. This analogue of prostaglandin I2 is a potent relaxer of vascular smooth muscle, and it inhibits platelet aggregation. The pulmonary artery pressure was normal eight months after the start of therapy with beraprost sodium.
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PMID:[Systemic lupus erythematosus with pulmonary hypertension--normalization of pulmonary artery pressure by long-term administration of beraprost sodium]. 858 27

Two murine models of lupus were employed to challenge an hypothesized mechanism by which antiphospholipid antibodies (APLA) might promote thrombosis: altering prostacyclin (PGI2) and thromboxane (TX) production. PGI2 levels in mouse blood and the ex vivo release of PGI2 and TX from mouse kidney were measured. Since APLA have been reported to alter synthesis or activation of several molecules mediating fibrinolysis, murine plasma levels of the fibrin degradation product, D-dimer were also determined. Two murine strains, one prone to spontaneous "lupus-like" illness (MRL-lpr) and related strain (MRL-(+2)), were compared. The assays confirm that MRL-lpr mice have increased anticardiolipin antibody (ACA) and two-fold increased release of TX from renal tissues compared to MRL-(+2) mice. However, these mice have low levels of plasma D-dimer. NIH Swiss mice injected with IgG (containing APLA) from thrombosis-prone lupus patients had high blood ACA titers and D-dimer levels, but both ACA and D-dimer were low or non-detectable in Swiss mice injected with saline or normal IgG. Unlike mice with spontaneous lupus-like illness, healthy mice injected with APLA did not differ from controls with respect to plasma or tissue PGI2 or TX levels. The two murine models of lupus differ, because an altered PGI2-TX ratio is a finding in the chronic murine lupus strain MRL-lpr, but is not seen when APLA are injected into normal mice. It is unlikely that APLA alone has a direct effect on cellular production of eicosanoids in vivo.
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PMID:Discordant effects on eicosanoids and fibrin degradation products in two murine models of antiphospholipid antibody. 906 53

The risk factors of stroke in young adults and in the whole population are the same in general, but there are some special risk factors in young adults. They are congenital or early acquired diseases which are complicating with early stroke. We studied the risk factors of cerebrovascular insults in 150 patients, 20-49 years old (Table 1). This was 26.04 percent of all patients that were hospitally treated in the urgent neurological department over one year. However, twenty years ago, this percent was 20.20 [2]. We found that arterial hypertension was dominant both among young adults (47.99 percent) and in the whole population (Table 2) [1-3]. Essential hypertension was the most frequent, and renal and thyreotoxical hypertensions were rare. The atherogenic level of low density and high density lipoproteins (LDL/HDL) was present in 14.66 percent of young adult patients [3]. Diabetes mellitus, a known risk factor of stroke, was found in 5.33 percent of our studied patients, especially in the juvenile form [1-3]. Besides juvenile diabetes mellitus, we found other risk factors that were characteristic of young adults: systemic lupus erythematosus (3.33 percent), which began at an early vital age, and numerous cerebrovascular complications appeared during the first five years of illness [7]. In this group of young adults, we found no other type of vasculitis, which also can be a risk factor of stroke. Great risk factors of stroke in young adults were arterial-venous malformation, brain aneurysm and congenital muscular hypoplasia of the carotide and middle caliber cerebral arteries-multiple progressive intracranial arterial occlusion or Nishimoto Takeuchi disease or Moya Moya disease, which were found in 3.99 percent of our patients. These diseases were complicated by cerebrovascular haemorrhagic or ischaemic insults over the young vital period [9]. The similar was with congenital or early acquired (rheumatic fever) heart valve defects (3.99 percent in our group), with early cerebrovascular complications due to cardiogenic thromboembolism mechanisms [10]. In 2 percent of patients the stroke was the consequence of anticoagulant therapy. These were the patients with operated heart valve defects (haemodynamic risk factor was eliminated, but haemorrheological risk factor was evident) [2, 3]. Also, disturbances of cardiac rhythm were risk factors of stroke in 2 percent of our patients. The mechanism of stroke originated is cardiogenic thromboembolism or global hypotension and the following ischaemia in the border brain zone [11]. All these risk factors were present in a relatively small number of patients, but they were "strong" risk factors of stroke, especially in young adults. On the other hand, there were nicotinism, alcoholism and obesity. They were present in a greater percent (25.33; 15.66; 18.66 percent), but their influence was slow and indirect by haemorrheologic mechanism (the increasing aggregation of platelets, reduced flexibility of red and white blood cells, changed prostacycline-prostaglandin relation in endothelial and blood cells, viscosity of blood, LDL/HDL) [2, 3, 12, 13]. A prolonged psychogenic stress (8.66 percent in our group) was, also, a risk factor of stroke. It induced increase in catecholamine level, arterial hypertension, constriction of blood vessels, endothelial cell damages, increased aggregation of platelets, changed prostacycline-prostaglandin relation, metabolism of lipids and polysaccharides) [2, 3]. We found no abuse of ephedrine [16] or cocaine [15] as risk factors of stroke in our group, although it was described in litterature. Also, we found no postoperative thromboemolism (foramen ovale apertum). Ischaemic cerebrovascular insults dominated (77.34 percent) in our group of patients. In one article (Canada) [17] haemorrhagic insults were dominant in young adults. In our opinion, the number of our patients was not adequated, as haemorrhagic stroke is also treated in neurosurgical departments. The mor
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PMID:[Risk factors for stroke in young people]. 910 54

In conclusion, a revised view of the contact system has been presented. This system has little to do with the initiation of hemostasis. Like lupus anticoagulants, deficiencies of contact proteins give prolonged APTTs but may be risk factors for thrombosis. BK from kininogens is a potent modulator of vascular biology inducing vasodilation, tissue plasminogen activator release, and prostacyclin liberation. Kininogens, themselves, are selective inhibitors of alpha-thrombin-induced platelet activation preventing alpha-thrombin from cleaving the cloned thrombin receptor after arginine41. Kininogens' alpha-thrombin inhibitory activity exists in intact kininogens, BK, and all of BK's breakdown products. HK also is the pivotal protein for contact protein assembly on endothelium. It is the receptor for prekallikrein which when bound to HK becomes activated to kallikrein by an endothelial cell enzyme system independent of activated forms of plasma factor XII. Prekallikrein activation on endothelial cells results in kinetically favorable single chain urokinase and plasminogen activation. Thus the "physiologic, negatively charged surface" for contact system activation is really the assembly of these proteins on cell membranes and activation by membrane-associated enzymes.
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PMID:Contact activation: a revision. 919 36


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