Humoral factor that specifically regulates factor X levels in rabbits (coagulopoietin-X).

A heat-stable humoral substance (coagulopoietin-X) is present in rabbits partially depleted of Factor X, which is capable of raising Factor X levels when injected into recipient rabbits. Rabbits were partially depleted of Factor X by slow infusion of a globulin fraction of goat anti-rabbit Factor X antibody. This resulted in the reduction of Factor X to 40--50% of normal at 1 h and 60--70% of normal at 6 h. No effect was noted on levels of Factors II, V, or VII. Plasma from these animals, when injected into 10 recipients, specifically raised Factor X levels when measured by four different assay: one-stage assay with bovine VII- and X-deficient plasma and Russell's viper venom; one-stage assay with human X-deficient plasma and thromboplastin; chromogenic substrate assay with Russell's viper venom; and an immunologic assay (Laurell technique). No rise was noted in two control experiments in which normal plasma was injected into recipient rabbits from 2 rabbits injected with a globulin fraction of normal goat serum, nor in 12 rabbits injected with plasma from normal rabbits, nor in 5 rabbits injected with boiled plasma from normal rabbits. The rise in biologic activity of 120--150% of base line was significantly greater than the rise in immunologic activity of 114--117% of base line (P less than 0.05) on 3 different days, suggesting the production of a molecule with greater specific activity rather than increased protein synthesis.

Mendelian diseases among Roman Jews: implications for the origins of disease alleles.

The Roman Jewish community has been historically continuous in Rome since pre-Christian times and may have been progenitor to the Ashkenazi Jewish community. Despite a history of endogamy over the past 2000 yr, the historical record suggests that there was admixture with Ashkenazi and Sephardic Jews during the Middle Ages. To determine whether Roman and Ashkenazi Jews shared common signature mutations, we tested a group of 107 Roman Jews, representing 176 haploid sets of chromosomes. No mutations were found for Bloom syndrome, BRCA1, BRCA2, Canavan disease, Fanconi anemia complementation group C, or Tay-Sachs disease. Two unrelated individuals were positive for the 3849 + 10C->T cystic fibrosis mutation; one carried the N370S Gaucher disease mutation, and one carried the connexin 26 167delT mutation. Each of these was shown to be associated with the same haplotype of tightly linked microsatellite markers as that found among Ashkenazi Jews. In addition, 14 individuals had mutations in the familial Mediterranean fever gene and three unrelated individuals carried the factor XI type III mutation previously observed exclusively among Ashkenazi Jews. These findings suggest that the Gaucher, connexin 26, and familial Mediterranean fever mutations are over 2000 yr old, that the cystic fibrosis 3849 + 10kb C->T and factor XI type III mutations had a common origin in Ashkenazi and Roman Jews, and that other mutations prevalent among Ashkenazi Jews are of more recent origin.

Thrombocytopenia in children infected with human immunodeficiency virus: long-term follow-up and therapeutic considerations.

Among 180 children infected with human immunodeficiency virus (HIV-1), 14 (8%) developed thrombocytopenia during the course of the disease and have been followed for an average period of 18.8 months. Eight of 14 patients had clinical signs of bleeding. Increased levels of anti-platelet IgG antibodies were detected in 86% of patients tested and did not correlate with severity of disease. Eight patients were treated initially with intravenous immunoglobulins (IVIG) and responded with a transient increase in the platelet count of at least 30 x 10(9)/L. Sustained remission could not be achieved in the patients treated with IVIG alone. Corticosteroids were used in 6 patients who became refractory to IVIG and resulted in sustained remission in only one patient. Spontaneous remission of thrombocytopenia occurred in one patient. Ten patients were treated with zidovudine (ZVD) for a period of 3-20 months. Sustained improvement in the platelet counts occurred in only three of the children treated with ZVD.

Prothrombin synthesis in the adult and fetal liver.

Plasma levels of blood coagulation zymogens are lower in the newborn than in the adult, with the lowest levels being in preterm infants. It is not known if the lower coagulation factor levels reflect differences in synthesis, secretion or catabolism. Using a rabbit model we have compared prothrombin synthesis in the fetus and adult. In previous studies we attempted to compare transcription in the adult and fetal liver by extraction of mRNA, immobilization on a membrane and hybridization with a labeled cDNA for rabbit prothrombin. Comparison was impaired by the markedly dissimilar composition of fetal and adult rabbit liver; fetal liver is approximately fifty percent hematopoietic tissue even at term (1). In the present study, to obtain a more meaningful comparison we have employed in situ hybridization to compare directly prothrombin expression in adult and fetal liver. We report here that fetal liver contains more prothrombin mRNA than does adult liver. We have further compared prothrombin levels in protein extracts of adult and fetal liver and found that per microgram of extract, fetal liver contains as much prothrombin as does the adult. We conclude that the lower plasma prothrombin levels in the fetus do not reflect a lower rate of synthesis.

Cloning and partial sequence of a cDNA for rabbit prothrombin.

A 1466 base pair cDNA for rabbit prothrombin has been isolated and partially sequenced. The deduced amino acid sequence shows considerable homology with the sequences of human and bovine prothrombin. The cDNA extends from the equivalent of nucleotide 516 in the bovine sequence through the coding region and 99 nucleotides in the 3' non-coding region.

Diagnosis and management of disseminated intravascular coagulation.

Disseminated intravascular coagulation (defibrination syndrome, consumption coagulopathy) is a syndrome which may complicate a number of pathologic states. If clotting factors and platelets are "consumed" more rapidly than the patient can produce them, they may fall to levels which are not adequate for hemostasis. Thus, thrombosis with resulting necrosis and hemorrhage may occur simultaneously in the same patient. Local fibrinolysis (secondary fibrinolysis) may remove or partially remove intravascular thrombi, thus protecting against local tissue necrosis. Diagnosis of the fulminating syndrome is usually simple and depends upon a few relatively easy tests. If the syndrome is low grade, diagnosis is very difficult and may be impossible without sophisticated techniques. Differential diagnosis from coagulation defects secondary to liver disease is extremely difficult. Treatment in the fulminating case before intravascular thrombi can cause irreversible tissue damage is urgent. Treatment depends upon therapy of the underlying disease plus adequate heparinization. It may be necessary to administer platelets and blood fractions after heparinization. Corticosteroids are not contraindicated, particularly when the patient is heparinized. Epsilon-amino-caproic acid (EACA, Amicar) is contraindicated. This drug inhibits local fibrinolysis, which is protective to the patient.

Humoral factor that specifically regulates prothrombin (factor II) levels (coagulopoietin-II).

Prothrombin (Factor II) was decreased in rabbits by injection of a goat antiserum to prothrombin. When plasma from these rabbits was injected into normal animals, circulating prothrombin increased in the recipients, suggesting transfer of a humoral regulating factor ("coagulopoietin-II"). This coagulopoietin-II resisted boiling for 20 min. On Sephadex G-50 gel filtration, it remained in the retained volume, suggesting a molecular weight of less than 30,000. In an in vitro liver system, prothrombin increased in the incubation medium in the presence of coagulopoietin-II.

Immune thrombocytopenia in children.

Idiopathic thrombocytopenic purpura in the adult has a clearly established autoimmune etiology; IgG antiplatelet antibody is demonstrable on the patient's platelets and is frequently present in the serum. Platelet IgG is correlated inversely with the platelet count. In the acute childhood form of the disease, serum antibody is usually absent but increased IgG is present on the platelets, thus suggesting the immune nature of the childhood disease. The spleen acts as a significant source of antiplatelet antibody as well as the major reticulo-endothelial site for destruction of antibody-coated platelets. The majority of children with idiopathic (autoimmune) thrombocytopenia recover completely and have normal platelet counts within 6 months of diagnosis. Some patients recover after a longer period of time. Ten to 15 percent have a chronic form of the disease which is indistinguishable from the adult disease; splenectomy benefits approximately 70% of these patients.

Protein S in the first year of life.

Total protein S, free protein S and C4b binding protein were measured in healthy term infants in order to establish the normal levels of these proteins during the first year of life. Total protein S rose from 36.5% of the adult mean level on day 1 of life to 90% between 6 and 12 months of age. Free protein S was 54.2% of the adult mean on day 1 of life, all values were in the adult range by 2 months and the mean value was no different from the adult at 4 months. This relatively high level of free and presumably active protein S reflects low levels of C4bBP at birth (28.8% of the adult mean) and a slow postnatal rise.

Studies of the origin of platelet-associated fibrinogen.

Platelet membranes and whole platelet preparations were examined by crossed immunoelectrophoresis in normal individuals, in a patient with congenital afibrinogenemia, and in two unrelated patients with Glanzmann's thrombasthenia (types I and II) to study the origin of platelet-associated fibrinogen. Results indicate: (1) platelet and plasma fibrinogen are probably derived from the same gene product, (2) platelet fibrinogen is not derived from the surrounding plasma milieu, (3) under basal conditions, platelet fibrinogen is located only within the alpha-granules and not on the platelet surface, (4) addition of trypsin to fibrinogen uncovers either a neoantigen or a hidden pool of platelet fibrinogen in the alpha-granules, (5) platelets from two patients with Glanzmann's thrombasthenia contain near-normal quantities of fibrinogen.

Identification of a coagulopoietin for prothrombin.

A coagulopoietin specific for factor II has been demonstrated in the rabbit, and termed 'coagulopoietin-II'. A goat antiserum was used to lower the factor II level in a rabbit. When plasma from this rabbit was then injected into other rabbits, factor II rose in the recipients without increase in other coagulation factors measured (V, VII, and X). The coagulopoietin is stable to boiling for 30 minutes, and appear to have a molecular weight of less than 30,000.

Demonstration of kallikrein-like protease activity in nonactivated plasma of patients with Cooley's anemia.

Routine evaluation of 12 children with Cooley's anemia revealed that each one had a prolonged partial thromboplastin time. However, prothrombin time and thrombin time were within the normal range. Specific assays demonstrated low levels of the four contact factors: factors XI, XII, prekallikrein, and high molecular weight kininogen. Further investigation revealed activity against para-nitroanilide peptide substrates in unactivated plasma from all 12 patients. Following gel filtration on Sephadex G200, the activity emerged in one peak in the void volume, indicating a molecular weight of greater the 500,000. Activity was greatest against H-D-Pro-Phe-Arg-pNA, the substrate for plasma kallikrein, and was inhibited by diisopropyl fluorophosphate and trasolyl. It was unaffected by hirudin, soy bean trypsin inhibitor, and lima bean trypsin inhibitor. It was destroyed by heating at 56 degrees C. Specific antisera against human prekallikrein and human alpha-macroglobulin did not reduce the activity. It is concluded that a high molecular weight kallikrein-like protease, is present in the plasma of these patients. It is postulated that it is released into the circulation from tissue as a result of damage due to iron overload. It is further postulated that this protease brings about in vivo activation of the contrast factors, resulting in a fall in their circulating levels.