RESUMO
Levels of histamine, chymase, and tryptase were assessed in preparations of dispersed human TC (tryptase+, chymase+) mast cells obtained from foreskin and of dispersed human T (tryptase+, chymase-) mast cells obtained from lung. Consistent with previous immunohistochemical results, extracts of T mast cells, the predominant mast cell type in lung (93% T and 7% TC mast cells), were deficient in human chymase (less than 0.3 microgram and 0.04 U/10(6) mast cells) but not tryptase (10.8 micrograms and 0.3 U/10(6) mast cells) by corresponding immunologic and enzymatic (suc-L-ala-ala-pro-phe-p-nitroanilide in the presence of aprotinin and tosyl-L-gly-pro-lys-p-nitroanilide in the presence of soybean trypsin inhibitor, respectively) assays. The minor presence of chymase activity in lung could be accounted for by the minor presence of lung TC mast cells. Extracts of TC mast cells, the predominant mast cell type (1% T and 99% TC mast cells) in foreskin, contained both proteases. However, TC mast cells from adult foreskin contained eightfold to 10-fold higher levels of chymase (4.5 micrograms and 1.01 U/10(6) mast cells) and twofold to threefold higher levels of tryptase (11.5 micrograms and 0.27 U/10(6) mast cells) than did TC mast cells from newborn foreskin (less than 0.6 microgram and 0.09 U of chymase and 35 micrograms and 0.62 U of tryptase/10(6) mast cells). In contrast, histamine levels were not significantly different in adult foreskin TC (1.9 microgram/10(6) mast cells), newborn foreskin TC (1.6 microgram/10(6) mast cells), and adult lung T (1.5 microgram/10(6) mast cells) mast cells. The relative ratio of each mediator in newborn foreskin mast cells to that in adult foreskin mast cells is highest for histamine, followed by tryptase and then chymase. Tryptase from TC and T mast cells had identical subunit compositions by Western blot analysis and similar apparent specific activities. This study extends the previously reported immunohistochemical distinction between human T and TC mast cells in tissue sections by direct quantitation of chymase and tryptase in dispersed preparations of T and TC mast cells.
Assuntos
Endopeptidases/análise , Histamina/análise , Mastócitos/análise , Peptídeo Hidrolases/análise , Serina Endopeptidases , Linfócitos T/análise , Adulto , Quimases , Humanos , Pulmão/citologia , Masculino , Mastócitos/classificação , Pênis , Inibidores de Proteases , Pele/citologia , Especificidade por SubstratoRESUMO
Two regimens for infusing vancomycin over 1 h (500 mg every 6 h for five doses or 100 mg every 12 h for three doses) were used in 11 volunteers. Subjects received both regimens one week apart; the regimen used first for each subject was randomized. Nine receiving the 1000-mg dose experienced the "red-man (neck)" syndrome; none had the reaction while receiving the 500-mg dose (P = .002). Plasma histamine concentration, measured every 10 min during the first infusion of each regimen, increased in most subjects given 1000-mg doses; there was only a slight change in histamine levels after 500-mg doses. There was a significant relation between histamine release and reaction severity; frequency and severity of the reaction declined with subsequent doses. We conclude that the red-man syndrome occurs frequently in normal adults who receive 1000 mg of vancomycin over 1 h, that vancomycin causes an infusion rate-dependent increase in plasma histamine concentration, and that the increase in plasma histamine concentration is correlated with the severity of the reaction.