Mechanisms of Nonimmunological Histamine and Tryptase Release from Human Cutaneous Mast Cells

Background: If mast cells are stimulated they release multiple mediators that delineate markers for immunologic and nonimmunologic reactions; histamine and tryptase are the two best known. Although histamine can be assayed in plasma, it is a nonspecific marker with a very short half-life. Tryptase has a longer half-life, but its release has not been proven to be specific for anaphylaxis. The authors investigated the mechanisms of nonimmunologic histamine release from human cutaneous mast cells to understand the mechanisms of mediator release and to determine whether tryptase was specific for allergic mediated activation.

Methods: Dispersed mast cell suspensions isolated from neonatal foreskins underwent challenge with vancomycin, calcium ionophore A23187, morphine, and atracurium, and histamine-tryptase release was measured. The effects of calcium and magnesium, along with phospholipase C and phospholipase A2 inhibitors, also were investigated.

Results: Tryptase and histamine both were released by the known nonimmunologic stimuli (pharmacologic agents used in the current study; r2 = 0.6). Furthermore, vancomycin- and atracurium-induced histamine release was calcium dependent. Phospholipase C and phospholipase A2 inhibitors decreased vancomycin-induced histamine release, but not calcium ionophore A23187-induced release.     

Pressure-controlled palpation: a new technique which increases the reliability of manual palpation

The objective of the present study was to investigate whether the reliability of tenderness evaluation can be increased by using a new technique called "pressure-controlled palpation" (pcp). The technique has been made possible by a newly invented piece of equipment called a palpometer, with which a pressure-sensitive plastic film attached to the index finger records the pressure exerted. In 15 patients with chronic tension-type headache and in 15 healthy volunteers, 2 investigators studied myofascial tenderness using conventional palpation and pressure-controlled palpation. Tenderness was scored on a 4-point scale in each of the examined pericranial regions. The sum of tenderness scores recorded by two observers using conventional palpation differed significantly ( p = 0.0003), while results did not differ between observers using pressure-controlled palpation ( p = 0.89). During palpation with seven different pressure intensities a positive and linear relation between pressure and pain intensity was found ( p = 0.00006). Pain intensity reported by the subjects correlated highly with tenderness scored by the observer ( r_s = 0.95, p < 0.0001). These results demonstrate for the first time that tenderness scores can be compared between observers if palpation pressure is controlled. Pressure-controlled palpation represents a major improvement on current palpation techniques and should be standard in future research on myofascial pain disorders.     

HLA antigens in patients with lichen planus.

HLA-ABC antigens were determined in 89 patients with biopsy-confirmed lichen planus, and the HLA antigen frequencies were compared with those in 1967 controls. The younger patients were predominantly male, the older patients predominantly female. No significant association was found between HLA types and lichen planus in this study. A slightly greater incidence of HLA-A3 and B5 antigens was seen, but this increased frequency was not as pronounced as reported by others. When combined, available data on HLA and lichen planus indicate a slightly, but significantly, increased frequency of HLA-A3. None of the HLA antigens known to be associated with insulin-dependent diabetes are associated with lichen planus.