Biomedical subjects
G Treadwell
Publications and source records attributed to G Treadwell.
Mediator release in local heat urticaria: protection with combined H1 and H2 antagonists.
Two patients with local heat urticaria were examined for evidence of histamine release and for changes in mast cell morphology after local heat challenge. Both patients demonstrated significant release of histamine into the draining venous blood in the challenged arm. Biopsy specimens revealed mucosal edema after 30 min, followed by a mononuclear, perivascular infiltrate by 6 hr, and increasing in intensity by 24 hr. Degranulated mast cells were observed by electron microscopy. Heat challenge was repeated after treatment with hydroxyzine, cimetidine, or a combination of both drugs. Neither hydroxyzine nor cimetidine alone affected the clinical response to challenge, but both drugs together completely abolished the clinical response. In addition, the combination of both drugs taken regularly completely prevented symptoms. This observation suggests that histamine is one of the major mediators of this disorder and that both H1 and H2 receptors are operative.
Exercise-induced urticaria, angioedema, and anaphylactoid episodes.
Six subjects with exercise-induced anaphylactoid symptoms were evaluated by exercise challenge. Five of the six patients developed symptoms during free running. One subject developed only periorbital angioedema; another developed giant urticaria, wheeze, and hypotension; and three subjects developed cholinergic urticaria. One of the subjects with cholinergic urticaria also became hypotensive. Both of the subjects who developed hypotension also exhibited elevations in plasma histamine (11.2 and 23.2 ng/ml). Subjects who exhibited only cutaneous or subcutaneous manifestations failed to develop elevated levels of plasma histamine. Serum complement determinations (C'3, C'4) remained normal in all subjects at all time intervals. Thus exercise-induced anaphylactoid reactions can appear with a variety of cutaneous manifestations, including angioedema only, giant urticaria, and cholinergic urticaria. Elevated levels of plasma histamine are found only when systemic symptoms such as hypotension occur concomitantly.
Increased urine histamine and contrast media reactions.
Urine samples were collected from 200 subjects undergoing intravenous pyelography. The urine histamine levels were compared with those of 132 normal control subjects, 11 subjects with systemic mastocytosis, six subjects with idiopathic anaphylaxis, and ten subjects experiencing mild anaphylactic reactions during allergy immunotherapy. Compared with normal controls, as a group, all subjects receiving intravenous contrast media had increased urine histamine (P less than 0.05 by Student's t-test) while those subjects experiencing adverse reactions had considerably larger increases. The urine histamine levels in the subjects experiencing systemic reactions were in the same range as those observed in patients having mild anaphylactic reactions to immunotherapy and somewhat lower than those found in idiopathic anaphylaxis or systemic mastocytosis. These data suggest that some histamine release accompanies infusions of contrast media in all subjects and that larger amounts of histamine release are associated with adverse reactions.