Leiomyosarcoma of the superior vena cava and azygos vein.

A 40-year-old woman presented with facial swelling and pressure sensation of the ears and sinuses. Chest roentgenography revealed a right paratracheal mass, which was confirmed by a venogram, and transjugular biopsy showed low-grade leiomyosarcoma. The superior vena cava was resected and reconstructed using a spiral vein graft. Pathologic evaluation revealed a low-grade leiomyosarcoma arising from both the superior vena cava and the azygos vein with clear margins.

Coxsackie virus-induced acute pancreatitis in a long-term dialysis patient.

This report describes a patient on continuous ambulatory peritoneal dialysis (CAPD) who developed acute pancreatitis with pseudocyst formation and cloudy dialysate with pleocytosis in the absence of bacterial or fungal organisms. To our knowledge, pancreatitis, in the absence of hypertriglyceridemia in a CAPD patient, has not been previously reported. There was a significant increase in Coxsackie B1 and B6 viral titers by complement fixation test, suggesting Coxsackie virus-induced pancreatitis.

Benign intracranial hypertension: a complication of subclavian vein catheterization and arteriovenous fistula.

Thrombosis of the right innominate vein occurred in a patient on maintenance hemodialysis following repeated subclavian vein catheterization. The patient had a functional right brachial arteriovenous fistula for blood access that resulted in a massive retrograde blood flow into the cerebral venous system with the development of the benign intracranial hypertension. The symptoms and signs of intracranial hypertension abated following ligation of the arteriovenous fistula. This unusual association of benign intracranial hypertension with an arteriovenous fistula and innominate vein thrombosis has not been reported previously. Pertinent literature dealing with benign intracranial hypertension and complications of subclavian vein catheterization is reviewed.

Mechanisms of inhibition of active transport ATPases by mercurials.

Inhibition by methylmercury and mercuric chloride of Mg,Ca ATPase and Na,K ATPase activities in human erythrocyte ghosts was correlated with the binding capacity of ghosts for the mercurial. Full inhibition was always reached below saturation of binding capacity, and half-inhibition at levels as low as 10% saturation. Under such conditions, concentrations of free inhibitor were negligibly low, and existing mathematical models of inhibition were not applicable. New inhibitor partition equations were introduced to model the mechanisms of action of mercurials. Up to 7 methylmercury groups were calculated to bind to one Na,K ATPase molecule at non-inhibitory sites, while only one reacted with the inhibitory site. Mg,Ca ATPase showed simple one-hit inhibition (one mercurial per enzyme); further washing of ghosts, however, unmasked a second binding site (cooperative two-hit inhibition). Affinities of mercurials to sites of inhibition were calculated relative to other ligands in erythrocyte membranes: the ratios ranged from 3 : 1 to 50 : 1. The results demonstrated the use of binding capacity assays and inhibitor partition equations to measure and compare the susceptibilities of membrane-bound enzymes to poisoning by mercurials.

Binding of mercurials to membrane suspensions and undenatured proteins.

Binding capacities of membrane suspensions and dissolved compounds for mercurials were titrated by a new potentiometric method. Critical steps included a silver electrode of new design, the use of L-cysteine as a thiol buffer, a nitrogen atmosphere, and pretreatment of samples with equimolar mercurial and cysteine. Titrations had a sharp endpoint, accurate +/- 26 nmole methylmercury or +/- 8 nmole mercuric salt. Measurements of binding capacity of bovine serum albumin averaged 93% of the titer predicted for one SH group per molecule; those of human hemoglobin yielded 86-91% of the titer predicted for two SH groups per molecule. Yields dropped with exposure of protein solutions or membrane suspensions to atmospheric oxygen. Brain microsomes had significantly higher binding capacities (per milligram of protein) than red blood cell ghosts. The ratio of endpoint titers of CH3HgCl to HgCl2 averaged 2:1 in assays of cysteine, proteins, and membranes, showing that the assay was free of denaturation artifacts and protein-protein interference. Solutions of EDTA showed measurable binding of Hg2+ but not of CH3Hg+. Satisfactory titrations were also obtained with N-ethylmaleimide.