Faculty Bibliography

Skin biopsy specimens from four patients with erythema nodosum leprosum, when examined as Epon-embedded, 1-micron sections, exhibited a necrotizing vasculitis involving capillaries, venules, and small-to-medium arteries and veins. In the superficial dermis, affected venules and capillaries showed endothelial cell enlargement and focal necrosis associated with perivascular infiltrates of lymphocytes. In the deep dermis and subcutaneous tissue, affected venules, arterioles, and arteries exhibited endothelial cell necrosis and matted fibrin in the vessel walls associated with perivascular infiltrates of neutrophils. Throughout the dermis, mononuclear phagocytes with vacuoles containing numerous fragmented organisms were observed. By electron microscopy, electron-dense material resembling immune complexes was observed in the walls of these vessels. These observations support the concept that erythema nodosum leprosum is an immune complex-mediated necrotizing vasculitis involving capillaries, arterioles, arteries, venules, and veins

A monoclonal antibody (H4) against tryptase purified from human pulmonary mast cells was prepared and used as an immunoreactive marker for the cellular localization of tryptase in normal human skin and in lesional skin from subjects with systemic mastocytosis. Mast cells had characteristic metachromatic staining of cytoplasmic granules with Giemsa reagent and were detected in small numbers about superficial vessels in the papillary dermis of nonlesional skin and in large numbers about deep as well as superficial vessels of lesional skin. By both direct immunofluorescence with fluorescein isothiocyanate-H4 and indirect immunoperoxidase cytochemistry with H4, all mast cells were selectively stained. The reactivity was confined to the cytoplasm and was granular in character. In addition, keratinocytes in epidermal tissue and in cell suspensions stained diffusely with H4 antibody. A tryptase-like activity that cleaved tosyl-L-arginine methyl ester (0.003 U/10(6) cells) and was not inhibited by soy bean and lima bean trypsin inhibitors was detected in sonicated suspensions of purified epidermal keratinocytes. Monoclonal antitryptase antibody represents an immunologic probe for the presence of tryptase, a preformed mediator of human mast cells, in tissues and cells

Because of lack of direct evidence of histamine release by trimethaphan, the authors determined serum histamine levels and hemodynamic responses to trimethaphan administration in 19 consecutive patients. Group 1 patients (n = 7) received a single intravenous injection of trimethaphan, 0.5 mg X kg-1, while awake and again during stable halothane-nitrous oxide anesthesia. Group 2 patients (n = 6) were pretreated with intravenous H1 (chlorpheniramine, 0.1 mg X kg-1) and H2 (cimetidine, 4 mg X kg-1) receptor antagonists administered 15 min before trimethaphan, 0.5 mg X kg-1, in the awake and anesthetized states. In Group 3 (n = 6), the effects of infusion of trimethaphan, 3 mg X min-1 for 15 min, were studied during halothane-nitrous oxide anesthesia. In Group 1, bolus doses of trimethaphan were associated with maximal increases in serum histamine from 0.56 +/- 0.14 to 2.56 +/- 0.35 ng X ml-1 (P less than 0.01) and from 0.60 +/- 0.11 to 2.58 +/- 0.33 ng X ml-1 (P less than 0.01) 2 min after drug administration in the awake and anesthetized states, respectively; there were also clinical manifestations of histamine release. Mean arterial pressure decreased maximally after 5 min in the awake (from 92.0 +/- 3.4 to 69.9 +/- 2.2 mmHg; P less than 0.01) and anesthetized (from 82.6 +/- 3.7 to 57.3 +/- 2.5 mmHg; P less than 0.01) states, and was associated with increases in cardiac output and heart rate; stroke volume increased in the awake state only.(ABSTRACT TRUNCATED AT 250 WORDS)