PubMed · 5000488
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
P Fiddes, R Penny, P Castaldi. 1971-09-25. Protein-induced bleeding.. https://doi.org/10.5694/j.1326-5377.1971.tb92475.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
To explore the role of the key coagulation factor, fibrinogen, in development, hemostasis, wound repair, and disease pathogenesis, we disrupted the fibrinogen A alpha chain gene in mice. Homozygous, A alpha chain-deficient (A alpha-/-) mice are born normal in appearance, and there is no evidence of fetal loss of these animals based on the Mendelian pattern of transmission of the mutant A alpha chain allele. All of the component chains of fibrinogen (A alpha, B beta, and gamma) are immunologically undetectable in the circulation of both neonatal and adult A alpha-/- mice, and blood samples fail to either clot or support platelet aggregation in vitro. Overt bleeding events develop shortly after birth in approximately 30% of A alpha-/- mice, most frequently in the peritoneal cavity, skin, and soft tissues around joints. Remarkably, most newborns displaying signs of bleeding ultimately control the loss of blood, clear the affected tissues, and survive the neonatal period. Juveniles and young adult A alpha-/- mice are predisposed to spontaneous fatal abdominal hemorrhage, but long-term survival is variable and highly dependent on genetic background. The periodic rupture of ovarian follicles in breeding-age A alpha-/- females does not appear to significantly diminish life expectancy relative to males; however, pregnancy uniformly results in fatal uterine bleeding around the tenth day of gestation. Microscopic analysis of spontaneous lesions found in A alpha-/- mice suggests that fibrin(ogen) plays a fundamental role in the organization of cells at sites of injury.
Fibrinogen Richfield exemplifies a dysfibrinogen associated with a life-long thrombotic tendency. The evaluation of this novel case indicates that, like similar thrombotic dysfibrinogenemias, the abnormal protein polymerizes abnormally and demonstrates impaired clot dissolution. A survey of other cases of dysfibrinogenemia indicates that the relatively common abnormalities of Fibrinopeptide A release are generally asymptomatic or associated with bleeding, polymerization abnormalities are likely to be asymptomatic or associated with thrombosis (or occasionally bleeding), and complex abnormalities or additional, independent hemostatic defects are rather common. Thrombin and Reptilase clotting times are not helpful in distinguishing between the subsets, but clinical history, fibrinopeptide release, and polymerization studies may be useful. Abnormalities of fibrinogen function tend to correlate with changes in molecular domains related to binding and hydrolysis.
Orthotopic liver transplantation is now a successful treatment for end-stage liver diseases. Since most components of the coagulation system are synthesized by liver parenchymal cells, there is always a risk of genetic defects of hemostasis being transmitting by liver transplantation. Some coagulation factor defects, such as protein C deficiency, do not induce abnormalities in routine coagulation tests and, thus, go undetected before organ procurement. We report the first case, to our knowledge, of the transmission of heterozygous protein C deficiency, an autosomal recessive genetic defect, associated with dysfibrinogenemia, an autosomal dominant trait, by liver transplantation. Both the recipient and the donor presented with severe thrombotic complications. This case shows that potentially morbid genetic defects can be transmitted by organ transplantation, and it emphasizes the difficulty associated with organ procurement criteria, particularly for liver transplantation, in which routine blood tests appear insufficient for determining whether or not organs can or should be procured from a given donor.