The distribution of gonadotropin-releasing hormone (GnRH) was studied in the brain and infundibulum (INF) or median eminence of sheep utilizing a peroxidase-antiperoxidase immunohistochemical method. This procedure utilized a specific antiserum generated against GnRH conjugated to bovine serum albumin. In the rostral INF, the greatest concentration of GnRH positive axons was found in the medial region, mostly in the external layer dorsal to the hypophysial portal plexus. In the intermediate portion of the INF, the hormone was mainly observed in the external layer at the more dorsolateral areas ventral to the tuberoinfundibular sulcus. GnRH was generally located medially in the caudal portion of the INF and dorsomedially in the rostral infundibular stalk. Substantial amounts of reaction product were also noted in the internal layer throughout the entire rostrocaudal extent of the INF. The hormone was localized in axons throughout the brain from the septal and medial preoptic areas to the mammillary bodies. GnRH-positive perikarya were scattered in various regions of the infundibular (arcuate) and for the first time in the ventromedial nuclei of sheep hypothalamus. Preabsorption of the specific antiserum with synthetic GnRH abolished staining in both axons and perikarya, whereas preabsorption with thyrotropin-releasing hormone, oxytocin, arginine-vasopressin, and adrenocorticotrophic hormone did not affect staining intensity.

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Beer foam produced in a continuous foaming tower in volumes representative of commercial dispense, was analysed by immunoelectrophoretic and immunoblotting techniques to identify antigens involved In foam structural stability. In crossed immunoelectrophoresis (CIE), only one antigen precipitated from foam in the homologous foam antiserum. This antigen was shown to be of malt origin by rocket-line immunoelectrophoresis and was also present in 11 commercial beers (5 bitters, 4 lagers and 2 stouts). However, the foam preparation separated into more than 20 polypeptides by SDS polyacrylamide gel electrophoresls. Immunoblotting showed that at least 12 of these reacted with foam antiserum and that they originated from either malt or yeast. Similar polypeptides were also identified in the antigen precipitated in CIE, suggesting that these polypeptides were probably present in the foam as a complex. It is concluded that the stability of foam reflected molecular interactions between these polypeptides (and possibly other components such as carbohydrates) in the liquid film of the bubble structure.

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The influence of various dietary zinc levels on the fibrotic aspects of granuloma formation and on the humoral response to schistosome egg antigens was investigated in C57Bl/6 mice by feeding groups of animals zinc-deficient diets. At six weeks of age, control and zinc-deficient mice were exposed individually to 50-60 cercariae of the Brazilian LE strain of Schistosoma mansoni. The animals were maintained on their respective diets for eight weeks postinfection, then all animals were killed and analyzed for body weight, spleen weight, collagen content of the liver, in vivo granulomatous histopathology, and antibody responses to soluble egg antigens. Zinc-deficient mice experienced stunted growth and reduced weight gain. Granulomatous hypersensitivity to schistosome eggs in the liver was measured in liver histopathologic sections using morphometric analysis and was found to be depressed in infected mice fed the moderately and the severely zinc-deficient diets. The low level of zinc in the diet also affected the humoral immune response of the host to schistosome egg antigens.

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