The importance of yolk platelets in the embryonic and larval development of amphibians is indicated by the large proportion of oocytic material contained in these dense, subcellular structures. Of the total egg nitrogen, 69-72% is found in the yolk platelet fraction (Gregg and Ballentine,

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The effect of animal age on plasma protein composition was studied in the Mongolian gerbil, Meriones unguiculatus. Values for plasma protein fractions separated by electrophoresis were obtained from bromophenol blue-stained paper strips by elution and by scanning techniques, both of which yielded similar results. Total plasma proteins increased with age from 1 day to 28 months. Maximum albumin concentrations were attained at 3 months and maximum (adult) γ-globulin-fibrinogen concentrations at 28 months. A fast α2-globulin fraction was found in plasma from the youngest age group (1–3 days) but absent in older groups. No sex-related differences in plasma proteins were found for gerbils at 3 and 6 months. Age-related changes in gerbil plasma proteins are similar to changes found during the life span of many other mammalian species.

783pears to be the only known property of endotoxin to which tolerance does not develop. All other effects lead to a diminution of response, i.e., tolerance, on repeated adminis-Am.

No abstract