Immunochemical studies on blood groups. XLVII. The I antigen complex--precursors in the A, B, H, Lea, and leb blood group system--hemagglutination-inhibition studies

A partially purified blood group-like substance obtained from milk showed I activity with 2 of 21 anti-I sera. With these antisera, certain human ovarian cyst substances considered to be precursors of the A, B, H, Le(a), and Le(b) substances also showed I activity comparable to the milk material. Strong I activity could be produced by one-stage periodate oxidation and Smith degradation of human ovarian cyst A and B substances, or of hog mucin A + H substance, or by mild acid hydrolysis of human saliva or ovarian cyst blood group B substance. The two sera indicate that I specificity appears at intermediate stages in the biosynthesis of the A, B, H, Le(a), and Le(a) substances. Anti-I sera differ strikingly in their specificities, indicating substantial heterogeneity of the I determinants.

Ocular effects of changes in oxygen and carbon dioxide tension

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Two kinds of set in problem solving

A number of findings suggest that there are important differences between functional fixedness (FF) and Einstellung (E), though the significance of these findings seems to have gone unrecognized. The results of the present study suggest that FF and E (a) display different forgetting curves ( p < .001) and (b) respond differently to distribution of practice ( p < .05). Interpretations of the results are discussed.