Hereditary thrombosis in a Utah kindred is caused by a dysfunctional antithrombin III gene.

Maximum likelihood analysis of linkage between antithrombin III (ATIII) DNA polymorphisms and ATIII deficiency in a large Utah kindred suggests that thrombotic disease in this family is caused by a dysfunctional ATIII gene. ATIII-deficient family members were identified on the basis of: (1) reduced anticoagulant activity and (2) the presence of an electrophoretically abnormal inhibitor molecule in their plasmas. Affected individuals have two copies of the ATIII structural gene, and both alleles appear normal at the resolution of whole genome Southern blotting. However, family studies revealed statistically significant cosegregation of ATIII-deficiency trait and a particular ATIII DNA polymorphism haplotype (lod = 3.35; theta = 0.0); this result is consistent with the presence of a dysfunctional ATIII gene on a chromosome of the +, S haplotype.

False assignment of familial antithrombin III deficiency with the von Kaulla assay.

As a serum assay, the von Kaulla assay for antithrombin III has been criticized on the grounds that consumption of antithrombin III during in vitro blood clotting may lead to falsely low assay values. Use of the assay to screen a Utah pedigree for familial antithrombin III deficiency lends support to this criticism. In all, the assay was performed on 150 persons. Low values on the assay were corroborated by performing an alternative coagulation assay, an amidolytic assay, and an immunoassay. While all persons with historic evidence for a diagnosis of familial antithrombin III deficiency had low assay values, eight of 23 persons with low values had normal values on the other assays.

The improving hematologic picture in long-term surviving calves with total artificial hearts.

A coagulopathy associated with severe hemolysis was a limiting factor in obtaining long-term survivors among calves with total artificial hearts in 1969. Conversion of design from sac-type hearts to flexible diaphragm hearts, and from Silastic Dacron-fibril intimas to smooth polyurethane intimas, resulted in an abatement of the coagulopathy. In the most recent series of animals studied at this laboratory, platelet counts are normal and platelet survivals are half of normal. Plasma hemoglobins are normal. The coagulation system is still activated at specific loci within the total artificial heart, but is best compensated for in calves treated with antiplatelet drugs, having polyurethane hearts.

Radioactive labeling of protein carboxyl groups on factor VIII: use of carbodiimides for nuclear medicine.

Carbodiimides have been used to study macromolecular structure and to produce immunologically active antigens. We have used this method to label a labile coagulation protein, factor VIII, with 14C-glycine-ethyl-ester. No discernible chemical change, loss of biologic function in vitro, or alteration of the plasma disappearance of factor VIII resulted. The carbodiimide labeling method has potentially broad application because many biologic molecules contain carboxyl groups that are generally not critical to their chemical or immunologic character. This method can be used to incorporate short-lived positron emitters, such as 11C and 13N, into biologic compounds, or to attach ligands to useful antibodies for subsequent chelation to radioactive metals, such as 111In. Carbodiimides are especially useful for radionuclidic labeling of labile proteins because of the mild conditions, rapid reaction, and firmly attached label.

Factor-VIII activity and antigen, platelet count and biochemical changes after adrenoceptor stimulation.

Adrenaline, isoprenaline and salbutamol were administered by intravenous infusion to human subjects. Isoprenaline was covered with practolol in an attempt to reduce the unpleasantness of the circulatory effects. Changes were recorded in pulse rate and blood pressure, and in blood levels of factors V, VIII, X, XI, and XII, platelet count, lactate, pyruvate, potassium and free fatty acids. Factor VIII was studied by clotting assays, by reactions with two rabbit antisera and two human antibodies, and by desulphated agarose chromatography. At the rate at which they were adiminstered, all three drugs increased the pulse rate by 20-40 beats/min. Factor VIII rose c. 2.5 X with adrenaline but only c. 1.5 X with isoprenaline and salbutamol; but other clotting factors did not alter. Chromatography provided no evidence of a change in the size of the molecule carrying factor-VIII clotting activity. The rate of clearance of the heightened plasma activity could not be shown to differ from that of "ordinary" factor VIII infused into haemophiliacs. The platelet count rose after adrenaline, fell after salbutamol and did not change significantly after isoprenaline. Among the biochemical responses, the only significant difference between the drugs was that lactate rose after adrenaline and salbutamol but did not change after isoprenaline. The rise in factor-VIII clotting activity after adrenaline is considered to represent a real increase in blood concentration, presumably by release of additional factor VIII from stores. The evidence suggests that this could be classified as a beta2 effect; and that the quantity which can be released is unrelated to the current plasma level. The rise in platelet count produced by adrenaline may be the resultant of an alpha-mediated rise due to contraction of the exchangeable splenic pool and a beta2-mediated fall, the alpha effect predominating.

Noninvasive diagnosis of deep venous thrombosis.

Eighty-five patients suspected of having lower-extremity deep venous thrombosis (DVT) participated in a prospective study to test the diagnostic accuracy of four noninvasive techniques: Doppler ultrasonic flow study, electrical impedance plethysmography, the serial dilution protamine sulfate test, and an extensive physical examination. Ascending radiocontrast phlebography was the diagnostic standard of reference. We found that (1) when both Doppler and impedance examinations were positive, the diagnosis of DVT could be considered virtually certain; (2) impedance and Doppler examinations, when used in combination, were reliable screening tests capable of establishing or excluding the presence of thigh DVT; (3) physical examination and the serial dilution protamine sulfate test were unreliable screening techniques for DVT; (4) techniques other than the noninvasive methods investigated were needed to reliably detect or to exclude popliteal and call DVT.

A three-month survival of a calf with an artificial heart.

An artificial heart constructed from Biomer, a polyurethane, kept a calf alive for more than three months after its natural heart was removed. During this time all of the calf's vital organs apparently functioned well. We had been able to keep similar animals alive with Jarvik III hearts made from Silastic for one month. The principal problem encountered was the infection centering along the compressed air drive lines to the artificial heart. Another problem is thrombus formation in the artificial heart. Redesigning of the artificial ventricles to improve flow patterns and reduce material discontinuities should be attempted to eliminate localized thrombus formation within the ventricles. The rapid growth of the calf has led us to examine the possibility of alternative animal models for future long-term experiments. The most encouraging aspects of this experiment were the long survival time of the calf and the very low level of blood damage caused by the artificial heart.

Heparin metabolism and heparin-release lipase activity during long-term estrogen-progestin treatment.

Short-term oral contraceptive therapy has been reported to decrease postheparin lipolytic activity (PHLA). Resistance to heparin has been held responsible for this effect. To test several alternative explanations, we studied both PHLA and heparin concentrations in nine control women and nine women receiving long-term estrogen-progestin therapy after they were given heparin intravenously (10 units/kg). There were no significant differences in the concentration of heparin, its rate of disappearance, or calculated space of distribution between control and treated groups. PHLA was depressed (p less than 0.05) by approximately 50% during long-term estrongen-progestin therapy. PHLA disappearance was similar in both groups. Thus, reduced PHLA in women receiving long-term oral contraceptive therapy cannot be related to altered heparin metabolism or to accelerated enzyme disappearance from plasma. Long-term estrogen-progestin administration may decrease the heparin-facilitated release of individual triglyceride hydrolase activities or enhance the affinity of enzyme binding to tissues.

Multiple myeloma, cryoglobulinemia and xanthomatosis. Distinct clinical and biochemical syndromes in two patients.

Studies were carried out in two patients with multiple myeloma (immunoglobulin G, [IgG], K light chain), cryoglobulinemia and xanthomatosis with clinical features and lipid transport abnormalities which were quite different. One patient had nodular xanthomatosis and lipemia with delayed triglyceride and apolipoprotein removal. In vivo heparin resistance was present and heparin-paraprotein interaction was shown in vitro. The lipoprotein removal defect may have been due to impaired uptake of the "remnants" of glyceride-rich lipoproteins. Abnormalities were found both in primary platelet aggregation and in the platelet release reaction. The second patient had diffuse plane xanthomatosis with normal lipids. An orange cryoprecipitate contained IgG, beta- and prebeta lipoproteins, albumin, carotenoids and about half of the serumcholesterol. Triglyceride turnover was normal. These observations show that M-proteins may interfere with lipid transport by at least two mechanisms and illustrate the clinical diversity of xanthomatous myeloma.

One-stage assay of heparin.

A simple and rapid one-stage plasma heparin assay based on the heparin-dependent neutralization of activated factor X (Xa) is described. Factor Xa is prepared in a concentration adjusted to produce a clotting time of 18 to 20 seconds when heparin-free plasma is tested in the system. The assay incubation mixture contains "standard human plasma", the heparinized test plasma, cephalin, and factor Xa. Clotting times are measured automatically after incugation and calcium addition. A linear relationship was found between the log of the clotting time and the heparin concentration for the standard curve from which the heparin level is determined. The lower limit of sensitivity is about 0.05 unit heparin per milliliter. Dilution of test plasma is required to bring the heparin level to between 0.05 and 0.2 unit per milliliter. The standard curve is reproducible with a coefficient of variation of 2 to 4 per cent. Ten different, nonheparinized samples had clotting times of 18.9 plus or minus 1.0 (plus or minus 2 S.D.) seconds. Theoretically calculated and experimentally determined heparin levels after pulse injection of heparin agreed well in 5 volunteer subjects with r values between 0.93 and 0.99. This assay is not affected by normal variation in the plasma levels of fibrinogen, prothrombin, and factor V or by the plasma defects induced by coumadin.

A rapid, quantitative determination of clottable fibrinogen unaffected by heparin.

A turbidimetric assay for clottable plasma fibrinogen which is not sensitive to heparin or Pyran inhibition is described. The basis of the assay is the substitution of Reptilase-R for the thrombin usually employed. The assay correlates very well with a thrombin turbidimetric method and also has other advantages, including better stability of the clotting enzyme and more rapid attainment of equilibrium.