Interaction of fibronectin with heparin in model extracellular matrices: role of arginine residues and sulfate groups.

The interaction of heparin with the NH2-terminal domain of human plasma fibronectin was studied by using matrix-driven translocation, an assay for the adhesion of extracellular macromolecules with cell or particle surfaces within artificial collagen matrices. Partial desulfation of heparin rendered it ineffective in competitively inhibiting the interaction of the fibronectin NH2-terminal domain with heparin-coated particles, suggesting a role for sulfate groups of heparin in the interaction. Analysis of the fibronectin domain in terms of its primary structure, its proposed organization into "type I modules", and its hydrophilic and flexible segments led to the identification of several arginine-containing sites of potential interaction with the sulfate groups of heparin.

Characterization of human endothelial cell urokinase-type plasminogen activator receptor protein and messenger RNA.

Human umbilical vein endothelial cells in culture (HUVEC) express receptors for urokinase-type plasminogen activators (u-PA). The immunochemical nature of this receptor and its relationship to u-PA receptors expressed by other cell types is unknown. Cross-linking active site-blocked u-PA to HUVEC lead to an increase in its apparent molecular mass by approximately 40 Kd.

Interaction of single-chain urokinase-type plasminogen activator with human endothelial cells.

The interaction of urokinase-type plasminogen activators with receptors on the surface of endothelial cells may play an important role in the regulation of fibrinolysis and cell migration. Therefore, we investigated whether human umbilical vein endothelial cells (HUVEC) express receptors for single-chain urokinase (scu-PA) on the cell surface and examined the effect of such binding on plasminogen activator activity. Binding of 125I-labeled scu-PA to HUVEC, performed at 4 degrees C, was saturable, reversible, and specific (k+1 4 +/- 1 X 10(6) min-1 M-1, k-1 6.

Two accessory pathways, dual AV nodal conduction, and 1:2 ventriculoatrial conduction in a patient with multiple supraventricular tachycardias.

Multiple supraventricular tachycardias were induced in a patient with two left posterior accessory pathways and dual atrioventricular nodal conduction. One of the accessory pathways conducts slowly and exhibits decremental conduction. A "double retrograde response" (2:1 ventriculoatrial conduction) due to simultaneous retrograde propagation of a single ventricular depolarization over two longitudinally dissociated pathways plays a role not only in tachycardia initiation, but in the maintenance of a unique, irregular tachycardia.

Evolving patterns in the surgical treatment of malignant ventricular tachyarrhythmias.

The advent of the automatic implantable cardioverter defibrillator (AICD), generally viewed as a safe and effective intervention, has in some measure discouraged the use of electrophysiologically directed endocardial resection for intractable ventricular arrhythmias. We reviewed the records of 127 patients undergoing either AICD procedures or resection over a 6-year period. Thirty-day mortality was 5.

Predictors of rhythm disturbances and subsequent morbidity after the Fontan operation.

The electrocardiographic, hemodynamic and surgical data of 30 patients who underwent a Fontan operation between 1977 and 1986 were retrospectively reviewed to identify the incidence and predictors of immediate and late postoperative arrhythmias and associated morbidity in long-term survivors. Of 4 patients who died less than 1 year after operation (mortality 13%), 1 death was related to an arrhythmia. Three patients were not in sinus rhythm before operation and were excluded from the statistical analysis that examined predictors of arrhythmias.

Lipoprotein analysis. Early methods in the diagnosis of atherosclerosis.

Before 1950, there was no clear perception of the interrelationship of serum lipids, atherosclerosis, and coronary heart disease. Since then, research laboratories have made conflicting claims for the most useful measurement of the serum lipid levels in detecting and managing coronary heart disease. Emphasis has been placed in turn on the measurement of levels of serum cholesterol, lipoproteins, triglycerides, and, currently, cholesterol and lipoproteins again.

Martin Robison Delany (1812-1885): physician, black separatist, explorer, soldier.

Martin Robison Delany's great contribution to American life and black history stems from his defiant blackness. He was America's first "Black Nationalist" and the intense embodiment of black pride. Ever changing in his career, he always identified with the black experience and its place in history.

Hodgkin's disease: origin of an eponym--and one that got away.

Hodgkin's disease, the syndrome of enlarged lymph nodes associated with enlarged spleen, was described in 1832 on the basis of the gross appearance of the affected parts. The eponym entered the medical literature after repeated attempts by Dr. Samuel Wilks to credit Thomas Hodgkin with the priority of discovery.

Rapid self-terminating ventricular tachycardia induced during electrophysiologic study: a prospective evaluation.

The clinical significance of rapid self-terminating ventricular tachycardia induced during electrophysiologic study was prospectively evaluated in three patient groups with clinical ventricular arrhythmias. Group A (11 patients) had inducible rapid self-terminating ventricular tachycardia only (mean cycle length less than or equal to 250 ms and greater than or equal to 10 beats in duration). In Group B (22 patients) induction of this arrhythmia was followed by the induction of sustained ventricular tachycardia.

Device therapy of ventricular tachyarrhythmias.

Device therapy is becoming increasingly important in the management of patients with life-threatening ventricular arrhythmias. Currently, antitachycardia pacemakers and endovascular cardioverters are available on an experimental basis, while the AICD is commercially available. Although the first two devices are much easier to implant, their use is limited by their potential to accelerate a tachycardia or cause it to degenerate to ventricular fibrillation, and their lack of backup high energy defibrillation capabilities.

Electrophysiologic effects of thrombolytic therapy in patients with a transmural anterior myocardial infarction complicated by left ventricular aneurysm formation.

To assess the effects of early thrombolytic therapy on the incidence of clinical and induced ventricular arrhythmias in high risk postmyocardial infarction patients, 32 patients with a transmural anterior myocardial infarction complicated by left ventricular aneurysm formation were prospectively evaluated. Sixteen patients (Group A) received routine care because of contraindication to thrombolytic therapy or other factors and 16 (Group B) received either tissue plasminogen activator or streptokinase within 6 h of the onset of chest pain. The two groups were similar in left ventricular ejection fraction (mean +/- SD, 28 +/- 9% [Group A] versus 30 +/- 8% [Group B]) and occurrence of spontaneous nonsustained ventricular tachycardia, new bundle branch block and congestive heart failure.

Bradyarrhythmias, abnormalities of conduction, and indications for pacing in acute myocardial infarction.

Bradyarrhythmias and conduction disturbances are not infrequently observed in association with acute MI. The sinus node artery is supplied by the right coronary circulation only slightly more often than the left. As a result of concomitant vagotonia, however, sinus node dysfunction is more common with inferior infarction.

Location of specific oligosaccharides in heparin in terms of their distance from the protein linkage region in the native proteoglycan.

Studies were conducted to define the location of components and sequences in heparin with respect to their distance from the peptide linkage in the native proteoglycan. A purified heparin-oligopeptide was linked via its amino terminus to a matrix containing an azo bond and an activated carboxyl group. The polysaccharide chain was maximally degraded, either with heparinase or nitrous acid, and the soluble products were removed.

Dissociation of electrophysiologic and pharmacologic stability during an abbreviated oral loading regimen of amiodarone.

Thirty-three patients treated with an abbreviated oral amiodarone loading regimen for ventricular tachycardia underwent electrophysiologic testing in the control state, after 1 week of high-dose (1170 +/- 88 mg/day) inpatient therapy; and after an 8-week intermediate (669 +/- 129 mg/day) dosing phase. Serum levels of amiodarone and desethylamiodarone were measured by high-pressure liquid chromatography during follow-up electrophysiologic studies. Although the corrected sinus node recovery time, sinoatrial conduction time, and AH and HV intervals remained unchanged throughout the loading period, the sinus cycle length, Wenckebach cycle length, atrial and ventricular refractory periods, and ventricular tachycardia mean and return cycle lengths lengthened significantly by 1 week.