Differential effects of a partially purified preparation of slow-reacting substance of anaphylaxis on guinea pig tracheal spirals and parenchymal strips.

The contractile effects of partially purified slow-reacting substance of anaphylaxis (SRS-A) and histamine were compared on isolated guinea pig tracheal spirals and parenchymal strips. Histamine was equally active on both isolated tissues in a concentration-related fashion. SRS-A (0.1--10.0 U/ml) produced a concentration-related effect on parenchymal strips, whereas the tracheal spiral was 100 times less sensitive to this mediator. The contractile activity of SRS-A on parenchymal strips was diminished by incubation with limpet arylsulfatase and antagonized by FPL 55712, a known SRS-A antagonist. SRS-A, further purified by high pressure liquid chromatography, also demonstrated this preferential activity on guinea pig parenchymal strips. These data are consistent with the hypothesis, based on previous in vivo observations, that SRS-A is a selective peripheral airway constrictor.     

Effects of Intravenous Administration of Slow-Reacting Substance of Anaphylaxis, Histamine, Bradykinin, and Prostaglandin F2α on Pulmonary Mechanics in the Guinea Pig

The effects of intravenous administration of a purified preparation of slow-reacting substance of anaphylaxis (SRS-A), histamine, bradykinin, and prostaglandin F(2alpha) (PGF(2alpha)) on the mechanics of respiration were assessed in the unanesthetized guinea pig. Geometrically increasing doses of SRS-A resulted in graded decreases in average pulmonary compliance, with only modest increases in average pulmonary resistance. A dose with apparent maximal effects. 3,000 U/kg, resulted in a decrease of 49+/-7% of compliance below control values, with an increase in resistance of 24+/-8% above control. Intravenous administration of geometrically increasing amounts of histamine, bradykinin, and prostaglandin F(2alpha) also resulted in decreased compliance; but in each case this was accompanied by a marked increase in respiratory resistance. A decrease of compliance of approximately 50%, induced by intravenous histamine, bradykinin, or PGF(2alpha), was accompanied by an increase of 60-140% in resistance. Thus, intravenously administered SRS-A alters pulmonary mechanics with a more peripheral effect than any of the other agents tested.     

Pain and ischemic symptoms in craniocervical artery dissection

Arterial dissections of craniocervical arteries are being increasingly identified due to the growing awareness of the clinical picture and advances in imaging technologies. During a one-year period, we observed 20 patients with craniocervical artery dissection at cerebrovascular laboratory. Clinical picture, localization of the dissection and follow up studies were analyzed. Twenty study patients were divided into four groups: in group 1, all 4 patients with common carotid dissection with or without aortic dissection presented with pain; in group 2 with internal carotid dissection, pain was present in 5 out of 11 patients, ischemic symptoms in all 11 patients, and Horner syndrome or lower cranial nerve palsies in 3 of 11 patients; in group 3, all 4 patients with dissecting plaque were free from pain but had ischemic symptoms; and in group 4 there was only one patient with isolated vertebral artery dissection who had no pain but presented with stroke. Pain was the most prominent symptom in patients with lower craniocervical artery dissection. Ultrasound enabled follow up of the dissection.