Suppressive effects of soluble histocompatibility antigens on the in vitro generation of cytotoxic T cells to D-end alloantigens

Murine histocompatibility antigens were solubilized from the spleens and lungs of C57BL/6 (H-2b) animals with hypertonic salt (3 M KC1). Aggregate-free soluble antigens were incubated with nonadherent lymph node cells from BALB/c (H-2d) mice for 18 hr prior to their use as responder cells in the mixed-lymphocyte reaction (MLR). It was found that the generation of cytotoxic cells was suppressed while the proliferative response was not affected. The observed suppression was not due to a shift in the kinetics of the generation of cytotoxicity as determined throughout a 10-day culture period. The suppression was specific in that the response in MLR to unrelated H-2f stimulator cells and the subsequent generation of cytotoxic cells were unchanged. Using various H-2 recombinant strains as target cells in the assay of cell-mediated lympholysis, suppression of cytotoxicity was observed when the D end, but not the K end, was shared with the C57BL/6 strain from which the antigens were derived.     

Interaction between the Effects of Inside and Outside Na and K on Bullfrog Skin Potential

The composition of the solution bathing one border of the isolated frog skin affects the response of the potential across the skin to changes in the composition of the solution bathing the opposite border. Increasing the K concentration of the inside (corium) bathing solution decreased the sensitivity of the potential to a change in outside Na concentration. Decreasing the outside Na concentration decreased the sensitivity of the potential to a change in inside K concentration. Increasing the total ionic strength of the outside bathing solution or of both bathing solutions decreased the sensitivity of the potential to a change in outside Na concentration.     

Conditional Maximum Likelihood Estimation Following a Group Sequential Test

We consider estimation after a group sequential test. An estimator that is unbiased or has small bias may have substantial conditional bias (Troendle and Yu, 1999, Coburger and Wassmer, 2001). In this paper we derive the conditional maximum likelihood estimators of both the primary parameter and a secondary parameter, and investigate their properties within a conditional inference framework. The method applies to both the usual and adaptive group sequential test designs. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

ON THE HISTORY AND CHARACTERISTICS OF SOME MULTIPLE DISCOVERIES IN BOTANY, 1648–1965

Historians and others have given attention to multiple independent discoveries because of their implications for the nature of scientific discovery in general. However, previously published lists of such discoveries include almost no examples from botany. That this has been a matter of oversight is shown by the presentation of 22 cases of multiple botanical discoveries, the circumstances of which are briefly described. These examples show a number of the same general characteristics as those in other fields of science. They range in importance from the broadly sweeping to the narrowly specific, and show various degrees of simultaneity. They illustrate the problems of interpretation involved in judging functional equivalence, identity of central message, and priority. The bearing of some of the examples on various theories of the cause of multiple discoveries is also discussed. It is concluded that multiple discoveries have probably occurred as frequently in botany as in other sciences, and they display the same characteristics and generate the same problems of interpretation.     

The Last Passage: Recovering a Death of Our Own

The Last Passage: Recovering. Death of Our Own. Donald Heinz. New York: Oxford University Press. 1999. 296 pp.