[The usefulness of viscosimetry of vital human blood in internal medicine].
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The existence of a general abnormality in haemostasis causes more copious and protracted haemorrhage but does not, in theory, cause epistaxis. Abnormalities in primary haemostasis are at the root of these serious haemorrhages (thrombocytopenia and Willebrand's disease). Haemophilia is more rarely the trigger for intractable epistaxis. Treatment consists of local measures and replacement therapy. In all cases local treatment should have as little traumatic effect as possible in order to avoid a recurrence of haemorrhage when compression is removed. In women with abnormal constitutional haemostasis, establishment of anovulatory cycles by means of oestro-progestatives prescribed to combat menorrhagia often lessens the seriousness of these epistaxes. Replacement therapy consists of platelet transfusions for thrombocytopenia, the introduction of Willebrand's factor for Willebrand's disease and antihaemophilic factors for haemophilia.
Since it has not been established to what extent abnormalities of hemostasis contribute to the occurrence and development of dementia, selected measurements of coagulation and fibrinolysis were obtained in elderly patients with Alzheimer's disease (n = 22) or vascular dementia (n = 29), compared with healthy individuals in the same age range (n = 61). Hemostasis abnormalities were more frequent and marked in vascular dementia, being expressed as significant increases of plasminogen activator inhibitor type 1, von Willebrand factor, D-dimer and activated factor VII. However, some hemostasis measurements (von Willebrand factor, activated factor VII) were abnormally high also in the patients with Alzheimer's disease, a condition in which vascular damage is not considered to play a major pathogenetic role. It could not be established in this study whether or not these hemostatic abnormalities play a casual role in the pathogenesis of dementia, or whether they are secondary to inflammation and chronic vascular disease. Nevertheless, their presence may contribute to aggravating vascular disease.
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Thrombophilic disorders and hypofibrinolysis were demonstrated to be risk factors in a majority of women with recurrent pregnancy loss (RPL) and infertility. We investigated the association of FV G1691A mutation, F II G20210A gene polymorphism (PM), 4G/5G PAI-1 and Alu I/D tPA PM in 32 women with infertility and 49 women with at least 2 unexplained early abortions. FV Leiden mutation was significantly more common in women with RPL (10%, p = 0.02) and infertility (19%, p = 0.0005) compared with controls (2%). PAI-1 4G PM and t-PA Alu I PM, alone or in combination, were not associated with RPL or infertility. 9/49 women with RPL showed coagulation disorders with heterozygous FV Leiden mutation (5), FXII (1), protein C (1) or protein S (2) deficiency. However, due to the small number of patients studied, no definite conclusion can be drawn.
Plasma concentrations of antithrombin III (AT III), plasminogen (Plg), and protein C (PC) were assayed in 28 patients with venous thrombosis of lower extremities without distinct underlying disorders. Three abnormalities were found in 5 cases (17.8%) in relation to coagulation and fibrinolytic system (3 with congenital AT III deficiency, one each with dysplasminogenemia and congenital PC deficiency). In the patients with either one of these abnormalities, characteristic features of thrombosis are summarized as follows; 1. early onset of clinical symptoms. 2. high frequency of superficial vein thrombosis. 3. high recurrence rate. 4. high frequency of pulmonary embolism.
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Xenotransplantation is being pursued vigorously to solve the shortage of allogeneic donor organs. Experimental studies of the major xenoantigen (Gal) and of complement regulation enable model xenografts to survive hyperacute rejection. When the Gal antigen is removed or reduced and complement activation is controlled, the major barriers to xenograft survival include unregulated coagulation within the graft and cellular reactions involving macrophages, neutrophils, natural killer (NK) cells, and T lymphocytes. Unlike allografts, where specific immune responses are the sole barrier to graft survival, molecular differences between xenograft and recipient that affect normal receptor-ligand interactions (largely active at the cell surface and which may not be immunogenic), are also involved in xenograft failure. Transgenic strategies provide the best options to control antigen expression, complement activation, and coagulation. Although the Gal antigen can be eliminated by gene knockout in mice, that outcome has only become a possibility in pigs due to the recent cloning of pigs after nuclear transfer. Instead, the use of transgenic glycosyl transferase enzymes and glycosidases, which generate alternative terminal carbohydrates on glycolipids and glycoproteins, has reduced antigen in experimental models. As a result, novel strategies are being tested to seek the most effective solution. Transgenic pigs expressing human complement-regulating proteins (DAF/CD55, MCP/CD46, or CD59) have revealed that disordered regulation of the coagulation system requires attention. There will undoubtedly be other molecular incompatibilities that need addressing. Xenotransplantation, however, offers hope as a therapeutic solution and provides much information about homeostatic mechanisms.
Venous thrombosis is a cause of considerable morbidity and is often responsible for chronic venous disorders that frequently lead to visits to dermatologists and others involved in wound healing. Over the past several years, many new causes of thrombophilia have been identified and have dramatically altered the approach to patients presenting with thrombosis. Newly described abnormalities associated with thrombophilia include the syndrome of activated protein C resistance, the prothrombin 20210A mutation, hyperhomocysteinemia, and elevated levels of coagulation factors VIII and XI. Clinicians can now frequently determine causes of thromboses that have previously been deemed idiopathic.
Sufficient clotting factors to ensure coagulation and replacement of lost volume and oxygen-carrying capacity are necessary to obviate many of the complications that may occur when massive transfusions are used in patients with multiple injuries. A regimen that has been successful includes immediate infusion of plasma protein fraction, packed red cells, fresh-frozen plasma, and nonspecific platelets.
A 58-year-old man with multiple myeloma and paraproteinemia (IgG kappa) acquired cryoglobulinemia 2 years after the initial diagnosis of the disease. This cryoglobulin interfered specifically with fibrin aggregation. The patient's fibrinogen was functionally normal; however, clotting times (thrombin clotting time, reptilase clotting time) were prolonged in the untreated plasma and in the supernatant after removal of the cryoglobulins. Untreated patient's serum, and even more pronounced, the cryoprecipitate inhibited the association of fibrin monomers obtained from healthy controls. The inhibitory activity on fibrin aggregation diminished upon treatment-induced reduction of plasma protein levels.
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The primary mechanisms for coagulation were described more than a century ago. However, inherited disorders of coagulation have been recognized for only a few decades. Activated protein C resistance and other related protein defects account for many cases of hypercoagulability. Primary care physicians can initiate testing in individuals for whom there is a high degree of suspicion. Testing for specific disorders is best performed before initiation of anticoagulant therapy. Management often includes long-term warfarin therapy following initial anticoagulation with heparin.
A xenograft that performs efficient functions is an essential premise for successful xenotransplantation. Our early study indicated that Chinese Banna minipig inbred line (BMI) was an ideal xenograft donor. However, the activities of some proteins synthesized by the BMI liver are different from the human, which could lead to functional disorders in coagulation, fibrinolysis, and anticoagulation after liver xenotransplantation. Therefore, it is important to investigate the genetic background of protein incompatibility and to provide new strategies for gene manipulation. In this study we constructed a cDNA expression library using BMI liver tissue to obtain an understanding of nucleic acid and protein differences between the two species. We extracted total RNA and purified mRNA of the liver tissue from one of the sixteenth inbred generation of BMI/JS 151 substrain. After double-strand cDNA synthesis, we fractionated it on a CHROMA APIN-400 column; ligated the longer than 500bp cDNA into a ZAP Express Vector; and performed a lambda: phage packaging reaction, library amplification, and titer. We randomly picked 12 plaques and tested the length of inserts. The titers of the primary and amplified libraries were 1.0 x 10(6) pfu/mL and 5.0 x 10(9) pfu/mL, respectively. The percentages of recombinants were 97.0% in the primary library and 98.0% in the amplified library. The lengths of most inserts were between 750 bp and 2.0 kb. Thus, we successfully constructed a cDNA expression library from BMI liver tissue. Using the library, we hope to get a full-length cDNA of some important genes and conduct further studies on porcine liver function in xenotransplantation.
PURPOSE OF REVIEW: There is considerable evidence that dysregulation of the coagulation and fibrinolytic systems plays a major role in the pathophysiology of severe sepsis, with a special focus on the protein C system. Conversely, there is an approval for use of recombinant human activated protein C in the more severe patients. This review highlights recent findings about the biology of the protein C system and of other important coagulation components such as tissue factor, platelets, and protein S, with an effort to link fundamental data and recent clinical findings. RECENT FINDINGS: There is a better comprehension of the biology of the thrombomodulin-protein C-endothelial protein C receptor complex, and mainly of its cellular effects via the protease activated receptor 1 receptor and of its implication in the generation of anticoagulant microparticles. The implications of other important agents such as platelets and von Willebrand factor, tissue factor, and protein S are also becoming increasingly evident, both from experimental and clinical studies. From a clinical point of view, the more immediately promising approach could be the ability to identify the fraction of severe sepsis patients exhibiting an impaired ability to activate protein C, raising the possibility to select the better candidates for activated protein C infusion. SUMMARY: The comprehension of the protein C pathway is undoubtedly progressing both in experimental and clinical settings. In parallel, some promising other coagulant pathways are also under investigation in the sepsis context, with a hope for major clinical implications in the future.