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Biomedical subjects

D Stump

Publications and source records attributed to D Stump.

12 recordsLinked to original sources

Mechanism of benefit of combination thrombolytic therapy for acute myocardial infarction: a quantitative angiographic and hematologic study.

OBJECTIVES: The goal of this study was to lend insight into the mechanisms responsible for the beneficial effects of combination thrombolytic therapy. BACKGROUND: Combination thrombolytic therapy for acute myocardial infarction has been associated with less reocclusion and fewer in-hospital clinical events than has monotherapy. METHODS: Infarct-related quantitative coronary dimensions and hemostatic protein levels were evaluated in 287 patients with acute myocardial infarction during the early (90-min) and convalescent (7-day) phases after administration of recombinant tissue-type plasminogen activator (rt-PA), urokinase or combination rt-PA and urokinase. RESULTS: Minimal lumen diameter was similar in the 90-min and 7-day phases after treatment with rt-PA, urokinase and combination rt-PA and urokinase (0.72 +/- 0.45 mm, 0.62 +/- 0.53 mm and 0.75 +/- 0.58 mm, respectively, at 90 min, p = 0.16; and 1.05 +/- 0.56 mm, 1.12 +/- 0.72 mm and 0.94 +/- 0.54 mm, respectively, at 7 days, p = 0.22). In-hospital clinical event and reocclusion rates were less frequent in patients receiving combination therapy than in those receiving monotherapy (25% vs. 38% and 32% for rt-PA and urokinase, respectively, p = 0.084; and 3% vs. 13% and 9% for rt-PA and urokinase, respectively, p = 0.03), but these events were unrelated to early or late coronary dimensions. Patients receiving combination therapy or urokinase monotherapy had significantly higher peak fibrin degradation products (1,307 +/- 860 and 1,285 +/- 898 micrograms/ml vs. 435 +/- 717 micrograms/ml, respectively, p < 0.0001) and lower nadir fibrinogen levels (0.85 +/- 1.00 and 0.75 +/- 0.53 g/liter vs. 1.90 +/- 0.86 g/liter, respectively, p < 0.0001) than did those receiving rt-PA monotherapy. Peak fibrinogen degradation products indirectly correlated (p = 0.004) and baseline (p = 0.026) and nadir (p = 0.089) fibrinogen levels directly correlated with reocclusion. CONCLUSIONS: Lower in-hospital clinical event and reocclusion rates observed with combination thrombolytic therapy may relate to systemic hematologic factors rather than to the residual lumen obstruction after thrombolysis.

Blood Proteins

Adipocyte differentiation of 3T3-L1 cells involves augmented expression of a 43-kDa plasma membrane fatty acid-binding protein.

A previously described 43-kDa plasma membrane fatty acid-binding protein (FABPPM) was not observed by immunohistochemical methods in proliferating 3T3-L1 fibroblasts. However, it was detectable in plasma membranes by the second day of confluent growth, prior to accumulation of visible lipid droplets, and was strongly expressed in 8-day differentiated adipocytes. These observations were confirmed by extraction of plasma membrane proteins and subsequent immunoblotting. Kinetics of initial [3H]oleate uptake by both fibroblasts and adipocytes consisted of the sum of a saturable and a non-saturable component. During differentiation the saturable component increased progressively. Vmax increased from 3 to 25 to 110 pmol.s-1.mg cell protein-1 between the fibroblast, the 4-day, and 8 day adipocyte stages; Km was 24 nM in fibroblasts and approximately 55 nM in both 4- and 8-day differentiated adipocytes. By contrast, the rate constant for nonsaturable oleate influx decreased progressively from 0.026 to 0.010 ml.s-1.mg protein-1 between the fibroblast and 8 day adipocyte stages. In 8-day adipocytes saturable oleate uptake was inhibited by up to 55% by antibodies against rat liver FABPPM; these antibodies had no effect on uptake of 2-deoxyglucose or the medium chain fatty acid octanoate. They also had no effect on oleate uptake by fibroblasts. These studies support the hypothesis that FABPPM is a component of a saturable transport mechanism for long chain fatty acids.

3T3 Cells

Thrombosis-related markers in unstable angina pectoris.

While thrombus formation has been implicated in the pathogenesis of unstable angina, the value of thrombus-related markers for distinguishing unstable from stable angina is not well defined. Fibrin D-dimer and plasminogen activator inhibitor were prospectively analyzed in the peripheral blood of 46 patients (26 with unstable angina and 20 with stable angina or normal coronary arteries). Baseline blood samples were drawn within 24 h after rest pain in patients with unstable angina and in 19 of these 26 patients in less than 6 h. In patients with unstable angina, mean +/- SD (median) values for fibrin D-dimer and plasminogen activator inhibitor values measured 0.09 +/- 0.06 (0.07) microgram/ml and 9.1 +/- 9.6 (5.9) IU, respectively, compared to 0.11 +/- 0.10 (0.05) microgram/ml and 5.5 +/- 1.9 (5.0) IU/ml, in patients in the control group (p = NS for all comparisons between the two groups). Recurrent in-hospital pain, coronary anatomy and need for intervention showed no relation to the levels of these markers. In 19 additional patients (9 with unstable angina and 10 control patients) samples from the coronary sinus and the peripheral blood were also analyzed. Again, in patients with unstable angina all samples were drawn less than 24 h after rest pain; in six of nine patients samples were drawn in less than 6 h. A coronary sinus to peripheral blood gradient for either of these markers could not be demonstrated. The differences between peripheral and coronary sinus D-dimer and plasminogen activator inhibitor concentrations were also similar in patients with unstable angina and control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Unstable angina or non-Q wave infarction despite long-term aspirin: response to thrombolytic therapy with implications on mechanisms.

The pathophysiology and optimal therapy of patients who develop unstable angina in spite of long-term aspirin intake ("aspirin failure") have not been well defined. As part of a prospective study of thrombolytic therapy, 19 consecutive patients were identified who were admitted with unstable angina despite long-term aspirin therapy, and they were compared with 12 patients with unstable angina without previous aspirin use. Both groups received urokinase (3.0 million units over 30 minutes intravenously), maximal antianginal therapy, and intravenous heparin. Fibrinolytic system effects were characterized with serial measurements of fibrinogen, d-dimer, and fibrinogen degradation products (FDPs) at baseline and over the 24 hours following therapy. In comparison with those without previous aspirin use, the aspirin failure patients demonstrated greater d-dimer production after treatment at all points, the values becoming highly significant at 24 hours (1337 +/- 671 versus 709 +/- 620 ng/dl, p less than 0.02), as well as significantly greater FDPs at all points in the first 24 hours after treatment. Post-treatment arteriography (at 24 to 72 hours) indicated more extensive coronary artery disease in the aspirin failure patients (2.56 +/- 8.3 versus 1.63 +/- 1.06 vessels with greater than 50% stenosis, p less than 0.01) and more severe stenoses of the culprit artery (92.7 +/- 22.9% versus 77.3 +/- 36.9% diameter reduction, p = 0.09). By 7 days, both groups had equally low rates of new ischemic events or infarction (3 of 12 for no aspirin versus 4 of 19 for aspirin failure patients). Despite more extensive underlying coronary disease, unstable angina after long-term aspirin therapy appears to respond equally well to thrombolytic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Plasma membrane fatty acid-binding protein and mitochondrial glutamic-oxaloacetic transaminase of rat liver are related.

The hepatic plasma membrane fatty acid-binding protein (h-FABPPM) and the mitochondrial isoenzyme of glutamic-oxaloacetic transaminase (mGOT) of rat liver have similar amino acid compositions and identical amino acid sequences for residues 3-24. Both proteins migrate with an apparent molecular mass of 43 kDa on SDS/polyacrylamide gel electrophoresis, have a similar pattern of basic charge isomers on isoelectric focusing, are eluted similarly from four different high-performance liquid chromatographic columns, have absorption maxima at 435 nm under acid conditions and 354 nm at pH 8.3, and bind oleate with a Ka approximately 1.2-1.4 x 10(7) M-1. Sinusoidally enriched liver plasma membranes and purified h-FABPPM have GOT enzymatic activity; the relative specific activities (units/mg) of the membranes and purified protein suggest that h-FABPPM constitutes 1-2% of plasma membrane protein in the rat hepatocyte. Monospecific rabbit antiserum against h-FABPPM reacts on Western blotting with mGOT, and vice versa. Antisera against both proteins produce plasma membrane immunofluorescence in rat hepatocytes and selectively inhibit the hepatocellular uptake of [3H]oleate but not that of [35S]sulfobromophthalein or [14C]taurocholate. The inhibition of oleate uptake produced by anti-h-FABPPM can be eliminated by preincubation of the antiserum with mGOT; similarly, the plasma membrane immunofluorescence produced by either antiserum can be eliminated by preincubation with the other antigen. These data suggest that h-FABPPM and mGOT are closely related.

Amino Acid Sequence

Role of the clinical laboratory in monitoring fibrinolytic therapy of acute myocardial infarction.

Thrombolytic therapy is rapidly becoming a routine part of the treatment of acute myocardial infarction. The clinical laboratory is often called upon to help monitor changes in the hemostatic system in these patients. This review will address laboratory monitoring of patients treated with the two most commonly used thrombolytic agents: streptokinase (SK) and recombinant tissue plasminogen activator (rt-PA). The fibrinolytic system and recent clinical trials are discussed. This is followed by a review of available assays and their place in therapeutic monitoring.

Blood Coagulation Tests

The use of tissue-type plasminogen activator for acute myocardial infarction in the elderly: results from thrombolysis in myocardial infarction Phase I, open label studies and the Thrombolysis in Myocardial Infarction Phase II pilot study. The TIMI Investigators.

The impact of age on hospital mortality, incidence of major hemorrhagic events and transfusion requirements was examined in 756 patients with acute myocardial infarction enrolled in the Thrombolysis in Myocardial Infarction (TIMI) Phase I, open label studies and the TIMI Phase II pilot study. The mortality rate significantly increased with age and was 3.5%, 11.5% and 12% in patients less than 65, 65 to 69 and 70 to 76 years of age, respectively (p less than 0.001). Logistic regression analyses selected female gender, diabetes mellitus, extensive coronary artery disease, history of congestive heart failure, continuing chest pain immediately after recombinant tissue-type plasminogen activator (rt-PA) administration, low systolic blood pressure at the time of admission and advanced age as variables predictive of in-hospital death. The incidence of major hemorrhagic events among patients not undergoing cardiac surgery during hospitalization was 8.7%, 14.5% and 24.7% in patients aged less than 65, 65 to 69 and greater than or equal to 70 years, respectively (p less than 0.001). The majority of hemorrhages were secondary to cardiac catheterization or puncture wounds. Variables related to a major hemorrhagic event included protocol, age, rt-PA dose/kg body weight and elevated diastolic blood pressure on admission. Of five intracranial bleeding events, three occurred in patients greater than 65 years. Transfusion requirements significantly increased with age (p less than 0.001). Reperfusion status at 90 min in the TIMI Phase I and open label studies A to C was similar in the three age groups studied and ranged from 60% to 71%.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors

Vertebral sarcoidosis in adolescents.

Two cases of vertebral sarcoidosis in pediatric patients are presented. All such patients reported have been black, 13-15 years old, and have a history of back pain. Radiographs of the involved vertebrae show primarily lytic destruction with sclerotic borders in some of the lesions. Fungal infections, tuberculosis, pyogenic osteomyelitis, Hodgkin's disease and metastatic disease must be considered in every patient with vertebral sarcoidosis.

Adolescent

Quantitation of plasma membrane fatty acid-binding protein by enzyme dilution and monoclonal antibody based immunoassay.

A plasma membrane fatty acid-binding protein (h-FABPpm) has been isolated from rat hepatocytes. Analogous proteins have also been identified in adipocytes, jejunal enterocytes and cardiac myocytes, all cells with high transmembrane fluxes of fatty acids. These 43 kDa, highly basic (pI = 9.1) FABPpm's appear unrelated to the smaller, cytosolic FABP's (designated FABP's) identified previously in the same tissues. h-FABPpm appears closely related to the mitochondrial isoform of glutamic-oxaloacetic transaminase (mGOT), and both the purified protein and liver cell plasma membranes (LPM) possess GOT enzymatic activity. From their relative GOT specific activities it is estimated that h-FABPpm constitutes approximately 2% of LPM protein, or about 0.7 x 10(7) sites per cell. A monoclonal antibody-based competitive inhibition enzyme immunoassay (CIEIA) for h-FABPpm is described; it yields an estimate of 3.4 x 10(7) h-FABPpm sites per hepatocyte. Quantitated by either method, h-FABPpm appears to be a highly abundant protein constituent of LPM.

Animals