Study of oxtriphylline SA in 50 asthmatics

Fifty clinically stable patients with asthma on maintenance theophylline therapy, mean dose of 15 mg kg-1 per day, were switched to an equivalent dose (X 1.56) of oxtriphylline SA for seven doses. All subjects remained clinically stable after the change during the study period. Oxtriphylline SA appears to be useful for the maintenance treatment of asthma and can be safely substituted for other theophylline maintenance regimens.

Neurologic sequelae following the imported fire ant sting

Four cases are described in which neurologic disturbances are the presenting symptoms after the imported fire ant (IFA) sting. The neurologic sequelae include focal motor and grand mal seizures and a mononeuropathy. The possible pathogenesis of these disorders is discussed.

Effects of toxin of red tide, Ptychodiscus brevis, on canine tracheal smooth muscle: a possible new asthma-triggering mechanism

The red tide toxin produced by Ptychodiscus brevis becomes airborne by the thrashing action of the surf and wind and induces cough, rhinorrhea, watery eyes, and sneezing in normal humans and wheezing in asthmatic patients. The mechanism of the contractile response induced by P. brevis toxin (PBTX) was investigated with isolated canine tracheal smooth muscle. Tetrodotoxin and atropine blocked the contractile effect of PBTX, and neostigmine potentiated the contraction. Mepyramine, phentolamine, methysergide, and chlorisondamine did not inhibit the effect of PBTX. This is the first description of a naturally occurring airborne substance that causes smooth muscle contraction by stimulating the axon sodium channels, resulting in the release of acetylcholine at postganglionic parasympathetic efferent nerve endings. The in vitro effect of PBTX on canine tracheal smooth muscle indicates that PBTX is capable of causing respiratory irritation and thus may precipitate an asthmatic attack. It is possible, however, that the mechanism is vivo may also include stimulation of a cough receptor reflex and/or stimulation of sodium channels of afferent vagus nerve fibers. In vitro evidence suggests that isoproterenol, atropine, and verapamil may be used to eliminate or prevent the respiratory symptoms that follow exposure to airborne red tide toxin. The use of high-pressure liquid chromatography separated fractions indicates that the neurotoxic component, not the hemolytic component, is responsible for contractions.

Treatment of local skin response to imported fire ant sting

The sting of the imported fire ant (IFA), Solenopsis invicta Buren and Solenopsis richteri Forel, produces characteristic sterile pustules. Substantial morbidity and occasional mortality from secondary infection of the IFA pustule(s) or anaphylaxis in hypersensitive persons has occurred. IFAs are found in the southeastern and south central United States. The effects of various medical regimens currently used to treat IFA pustules were evaluated clinically and histologically in rabbits. Neither prophylaxis before the sting nor treatment after the sting altered the clinical or pathologic course of the IFA pustule in rabbit skin.

A multicenter study on skin-test reactivity of human volunteers to venom as compared with whole body Hymenoptera antigens

Twenty-four control and 104 stinging insect-allergic patients were tested in this multicenter study, which compared the utility of individual venom and whole body extract (WBE) preparations for diagnosis. This study indicates that venom skin testing is more specific and more reliable than is testing with WBE. There was a high rate of WBE skin-test reactivity among controls. False-positive skin testing with venom was not a problem at concentrations of 1 microgram/ml or less. Only one mild and easily treated adverse reaction occurred in this study.

Refractory period to aspirin in a patient with aspirin-induced asthma

Oral aspirin challenge was used to detect unrecognized aspirin intolerance in a select group of 50 asthmatic patients who denied aspirin intolerance. A double-blind protocol was used to further study those patients who reacted to initial graded aspirin challenge. In one patient the use of a double-blind protocol led to the serendipitous discovery of a 72-hr refractory period to the adverse effects of aspirin, after initial ingestion of aspirin resulted in respiratory and systemic symptoms.