Biomedical subjects

D J Baughman

Publications and source records attributed to D J Baughman.

9 recordsLinked to original sources

PubMed1989

Prevention of venous thrombosis after total hip arthroplasty. Antithrombin III and low-dose heparin compared with dextran 40.

The anticoagulant action of heparin is mediated through antithrombin III, and the postoperative decrease in the plasma concentration of antithrombin III may contribute to the relative ineffectiveness of prophylaxis with low-dose heparin in preventing venous thrombosis after total hip arthroplasty. We conducted a prospective, randomized trial to compare the effectiveness of a regimen of antithrombin III, given intravenously once daily, and low-dose heparin with a regimen of dextran 40, given intravenously, in preventing venographically documented venous thrombosis after total hip arthroplasty. The results demonstrated an incidence of venous thrombosis of 4.9 per cent in patients who received antithrombin III and heparin; this was significantly lower than the incidence (28.6 per cent) in patients who received dextran 40 (p less than 0.005). Venous thrombosis occurred only in patients who had total hip arthroplasty with a cemented prosthesis (fourteen of fifty-seven patients, or 24.6 per cent); none of the twenty-six patients in whom a non-cemented prosthesis was used had venous thrombosis (p less than 0.01). Of the patients in whom a cemented prosthesis had been inserted, the incidence of venous thrombosis was lower in those who were treated with antithrombin III and heparin (7.4 per cent) than in those who were treated with dextran 40 (40 per cent) (p less than 0.005). Postoperative levels of antithrombin III were maintained at more than 90 per cent of the baseline level in patients who received it; this was significantly higher than in patients who received dextran 40.(ABSTRACT TRUNCATED AT 250 WORDS)

Antithrombin III↗

PubMed1982

Thrombin activation rate constant: one-stage chromogenic assay for the extrinsic system.

Some properties of a one-stage, chromogenic clotting assay using tissue thromboplastin as an activator are described. The chromogenic assay uses S-2238 as substrate and estimates thrombin by the rate of absorbance produced. Under assay conditions, it was observed that the log (thrombin or absorbance/min) is linear with time. The linearity appeared to extend from zero thrombin up to maximum thrombin concentration for all concentrations of each plasma type examined including factor V and factor VII deficient plasmas. Since the linear slope, b, appears to be a measure of the rate of thrombin production, it was called the Thrombin Activation Rate Constant (TARC). For dilutions of normal plasma log (b) appears to be linearly related to log (plasma concentration) and to log (PT) where PT is the standard one stage clotting time. For plasmas deficient in extrinsic clotting factors, b was linearly related to log (factor concentrations). The chromogenic assay was most sensitive to changes in prothrombin; least sensitive to changes in factor VII; and unaffected by changes in concentration of factors VIII and IX. The standard PT was least sensitive to prothrombin and more sensitive to factors X and VII. For oral anticoagulated plasmas log b and log PT were linearly correlated with a regression slope which was more negative than that from normal plasma. From theses results it was concluded that TARC is a chromogenic assay sensitive to all factors in the extrinsic pathway; that TARC might be used as both a screening assay for extrinsic deficiencies and a monitoring assay for anticoagulants; and that TARC may be more sensitive than the standard PT to the defects from oral anticoagulation.

Anticoagulants↗

PubMed1982

Association of recurrent myocardial infarction with hemostatic factors: a prospective study.

In a perspective blind study of 147 survivors of myocardial infarction, the 13 patients who had definite recurrent infarction during 38.1 +/- 7.2 months (minimum, 34 months) of follow-up had higher plasma fibrinogen levels (334.4 +/- 13.1 mg/dl vs 291.5 +/- 4.7 mg/dl; P = 0.0055), and higher maximum rate of fibrin growth (generation of turbidity) when measuring prothrombin time (PT Vmax, 7.76 +/- 0.31 units vs 6.48 +/- 0.11 units; P = 0.0003), thrombin time (TT Vmax, 5.24 +/- 0.32 units vs 4.22 +/- 0.11 units; P = 0.0002), and activated partial thromboplastin time (APTT Vmax, 7.47 +/- 0.29 units vs 6.20 +/- 0.10 units; P = 0.0001) than patients who did not have reinfarction. Eleven of the 13 reinfarctions occurred among the quartile (37 patients) with the highest PT Vmax, while only two reinfarctions occurred among the remaining 110 patients (risk ratio, 16.5). The quartile with highest APTT Vmax included nine reinfarctions (risk ratio, 6.7), and the quartiles with the most fibrinogen and largest TT Vmax included eight of the 13 reinfarctions (risk ratio, 4.8). Significant associations (P = 0.018 to 0.005, risk ratios, 2.5 to 4.8) of reinfarction with the values of Vmax corrected for fibrinogen were also found. These findings support recent evidence that hemostatic function contributes to the pathogenesis of the complications of coronary artery disease.

Adult↗

PubMed1981

Effect of sera on thrombin activation rate constants: a one-stage assay for the extrinsic system.

A one-stage chromogenic assay sensitive to all factors of the extrinsic system has been developed. Diluted plasma is combined with tissue thromboplastin in the presence of S-2238, a thrombin-sensitive substrate. After a lag phase, log (A405/min) is linear with time up to the maximal thrombin concentration. The linear slope, b, is called the thrombin activation rate constant (TARC). Log b, or b, is linearly related to log transformations of plasma dilutions, of factor concentrations, of dicumarolized plasmas, and of one-stage prothrombin times. Since the lag phase can vary from 2 to more than 10 minutes, it is difficult to perform the assay on current automated equipment. Results show that factors VII and X affect the lag phase, while factors V and II do not. Small amounts of sera or thrombin, to a lesser extent, can shorten the lag phase to near zero without altering the relationships between TARC and plasma dilutions and between TARC and prothrombin times for dicumarolized plasmas and for dilutions of factor-deficient plasmas. The only effects of some sera are to increase b by approximately 20 percent. Successful sera can be made from clotted whole blood or supernatants of sera from citrated plasma clotted with tissue of partial thromboplastins. These sera appear to have minimal amounts of factor X, undetectable prothrombin, and undetectable free thrombin. The sera contain excesses of factor VII and/or factor VIIa and nearly 20 percent of factor V. If the sera activity arises from the extrinsic system, it is probably due to factor VIIa.

Antithrombin III↗

PubMed1974