Electron microscopic and X-ray microanalytic studies were performed on four cases of argyria; one generalized and three localized. Deposition of electron dense granules was predominantly found on elastic fibers and around basal laminas of secretory portions of eccrine glands, although the amount of deposition was much less in the case of generalized argyria. In all four cases, X-ray microanalysis revealed that the depositions consisted mainly of silver, selenium, and sulfur. The importance of selenium in the detoxification of heavy metals was discussed.
1 The release of prostaglandin D2 (PGD2) during immediate allergic reactions in human skin was investigated in vivo and in vitro. 2 Skin exudates were collected from abraded sites on the thigh of atopic subjects sensitive to D. pteronyssinus antigen and from non-atopic control subjects. Challenge with antigen caused the release of PGD2 and histamine, but not PGE2, from the skin of the atopic subjects. The molar ratio of histamine to PGD2 was about 140: 1. Control subjects were unresponsive. 3 PGD2 was released from passively sensitized human skin challenged with antigen in vitro. The time course was similar in vitro and in vivo. The ratio of histamine to PGD2 in vitro was 78: 1. 4 The identities of the prostaglandins were confirmed by high performance liquid chromatography and radioimmunoassay to PGD2 and PGE2. 5 PGD2 is the major arachidonic acid cyclo-oxygenase product synthesized by human mast cells. It is pro-inflammatory in human skin but its functions as a mediator in immediate hypersensitivity reactions in human skin are not clear. The results of this study suggest that, relative to histamine, PGD2 contributes little to the oedema and erythema of immediate reactions in human skin.
Intradermal skin tests and in vitro antigen‐induced histamine release from leucocytes were carried out using mite, house dust and candida allergens in 49 patients with chronic urticaria in whom the cause was not identifiable from the history. None of them had other atopic diseases. Among the 49 cases, the number of patients who gave positive skin reactions to different allergens was as follows: mite, 24; house dust, 18; candida, 17. Significant histamine release from leucocytes by mite antigen was observed in 8 out of 12 patients who had 2+ or 3+ skin reactions. The present results suggest that mite, house dust and candida allergens may play a role in chronic urticaria, and especially that the mite may be one of the possible allergens in chronic urticaria.
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