To understand the mechanisms involved in immunological tolerance to skin-associated proteins, we have developed trangenic (Tg) mice that express a model self antigen, membrane-bound ABSTRACTS 125 FS01.3 Disperse (yes), orange (yes), 3 (no): what do we test in textile dye dermatitis?Para-phenylenediamine (PPD), an arylamine dye, is a strong allergen causing allergic contact dermatitis. Cytokines such as TNF-a and IL-1beta are key mediators in the initiation of this reaction. Both cytokines are predominantly produced by stimulated monocytes and macroghages. We investigated the responses of PPD and Bandrowski's base (BB), an autoxidation product of PPD in human monocytes. We isolated monocytes from healthy volunteers and incubated them with the allergens. TNF-a and IL-1beta mRNA expression and protein levels were estimated after 45 min, 2 h, 4 h and 24 h after allergen contact. IL-1beta and TNF-alpha were measured in cell culture supernatants by ELISA (n ¼ 7) and mRNA expression was determined by real-time RT-PCR. We found that PPD reduced TNF-a protein secretion by 20-69.9% (n ¼ 6). Further, IL-1beta levels were decreased by 44-98%. The same tendency was found studying IL-1beta and TNF-a mRNA steady state levels (n ¼ 3; 1 h incubation). These effects were substance-specific and not found for PPD derivatives nor for the autoxidation product BB. These findings suggest that PPD may specifically modify immune responses by directly infering with the cellular proinflammatory cytokine network.

aromatic hydrocarbons in the occupational environment: A review with special reference to benzo[a]pyrene measurements in Swedish industry. Scand j work environ health 8 (1982) 1-19. A review is given of measurements of polycyclic aromatic hydrocarbons (PAH) in the work environment in general with emphasis upon Swedish measurements of benzo[a]pyrene not previously published in international literature. Finally, epidemiologic investigations on PAHexposed workers, as well as threshold limit values for PAH, are discussed.

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ACETYLCOENZYME A (acetyl-CoA) plays a key role in the metabolism of fats and carbohydrates. It is also necessary as an acetyl donor for the in viuo formation of acetylcholine (ACh). During our investigations on the biosynthesis of ACh in the brain it became of interest to measure the amount of acetyl-CoA in this tissue. Acetyl-CoA has previously been determined in rat liver (BUHRING and KUHNAU, 1960; WIELAND, LOFFLER, WEISS and NEUFELDT, 1960;BORTZ and LYNEN, 1963; WIELAND and WEISS, 1963), but not in brain. The aim of the present paper is to describe a method for the determination of acetyl-CoA in the brain, which is based on previously described enzymic methods using citrate-condensing enzyme (CCE), but also includes a preliminary chromatographic separation of the compound on active carbon. The normal amount of acetyl-CoA in rat brain will also be reported. M A T E R I A L S A N D M E T H O D SAcetyl-CoA was prepared from acetic anhydride and coenzyme A according to SIMON and SHEMIN (1953), and was standardized enzymically (OCHOA, 1955a), taking the molar absorbancy of NADH at 340 nip as 6.22 x lo3. Active carbon (Nuchar C-190 'unground') was deactivated with stearic acid (6 per cent w/w) according to SYNGE and TISELIUS (1949). Crystalline CCE was prepared from pig heart according to SRERE and KOSICKI (1961). Malate dehydrogenase (MDH), NAD and CoA were obtained from the Sigma Chemical Company U.S.A. All other compounds were commercial products of the highest available purity. Female albino rats weighing approximately 200 g were used for the present studies.Preparation ofbrain extracts. Unless otherwise stated the rats were killed by immersion into liquid nitrogen. The brains (including the medulla oblongata) from three animals were dissected out, pooled and ground in a mortar chilled with liquid nitrogen. The powder was weighed and homogenized with four volumes of 6 % HCIO, in a Potter-Elvehjem glass homogenizer. The homogenate was centrifuged in a high-speed centrifuge (Beckman/Spinco, Model L rotor 40 at 30,000 rev/min, 30 min). The supernatant was decanted and the precipitate rehomogenized with two volumes of 6% HC10, and centrifuged as previously described. The pH of the combined supernatants was adjusted to 7.0 with 2 M-KOH. The solution was chilled at least 30 min in an ice-bath and centrifuged. The HCIO, precipitate was then washed with 5 ml of ice-cold water, the mixture being recentrifuged and the supernatant wash solution was combined with the previous supernatant. Chromatography of acetyl-CoA.The supernatant was allowed to reach room temperature and then applied to a carbon column. The extracts can, if necessary, be stored overnight at 4" without loss of acetyl-CoA. The carbon column was prepared in the following way. The stearic acid-treated carbon was suspended in water and degassed under vacuum. Most of the carbon accumulates at the surface, whereas the fines remain in the bulk of the water and can be removed. This step was repeated until no fines remained.A column (8 x 60 mm) of the flotated c...