We investigated the pathophysiology of rhinovirus colds by challenging volunteers with either of two strains of rhinovirus or with placebo. Nasal lavages were done before challenge and every 4 h for five days after challenge. We measured the levels of histamine, kinins, [3H]-N-alpha-p-tosyl-L-arginine methyl ester (TAME)-esterase activity, and albumin and counted the number of neutrophils in the recovered lavage fluid. Subjects who became both infected and symptomatic showed increases in levels of kinins (P less than .03), TAME-esterase activity (P less than .04), and albumin (P less than .05), as well as in the number of neutrophils (P less than .01). The total number of symptoms reported correlated significantly with the net increase in the concentration of kinins (r = .549; P less than .01), albumin (r = .674; P less than .001), TAME-esterase activity (r = .563; P less than .005), and neutrophils (r = .605; P less than .005). Levels of histamine did not change during the course of infection. During symptomatic rhinovirus infections (1) kinins are generated, (2) vascular permeability increases, (3) basophils and mast cells do not participate, and (4) neutrophils enter nasal secretions.

This study shows that this formulation of diclofenac potassium for oral solution is effective in reducing pain intensity within 30 minutes, which may be related to the 15-minute T(max) associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.

To determine how rat mothers protect their pups against pain, we applied focal heat (34-51 degrees C) to the ear or shoulder of 10-day-old rats that were isolated, in contact among themselves or with their mother, suckling nonnutritively, or in the hyperextension position normally caused by milk letdown. Relative to isolated rats, contact doubled withdrawal latencies from heat (43 or 45 degrees C) applied to the ear. Suckling quadrupled heat-escape latencies. During hyperextension, rats essentially did not escape from thermal stimulation of up to 48 degrees C. Protection provided by maternal contact, especially suckling, was not mediated by either mu or kappa opioid receptors: neither systemic injections of naltrexone nor norbinaltorphimine reduced heat-escape latencies. Morphine (0.125 and 0.250 mg/kg) added to the effects of contact but multiplied the effects of suckling to produce heat-escape latencies that were upward of 2 min.

This study demonstrates that aspirin is safe and effective for treatment of acute migraine in appropriately selected patients.

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