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The management techniques enforced by the Federal Reserve Board are noted with specific focus on its adamant stance on disclosure to the public regarding records of their most important meetings. There is a rule that places a five-year delay on meetings of the Federal Open Market Committee and the release of transcripts. This practice in the industry is discussed along with its impact.

The Federal Open Market Committee (FOMC) is allowed to practice routinely a draconian purge of records of its meetings. Transcripts are routinely shredded, and important segments of meetings declared 'off the tape.' The integrity of the public record requires that these practices cease.

Greenspan's publicly voiced declarations that interest rate increases have nothing to do with slowing down equity investing are belied by numerous statements to the Federal Open Markets Committee. There, Greenspan has repeatedly stated that euphoric investor behavior in the equities market is creating a bubble, and that Federal Reserve Board action has been geared toward gradually letting air out of that bubble.

Mature T cells are derived from prethymic stem cells, which arise at one or more extrathymic sites and enter and differentiate in the thymus. The nature of these prethymic stem cells is a critical factor for the formation of the T-cell repertoire. Although the bone marrow of adult mice can provide such stem cells, their origin during murine embryogenesis is still undetermined. Among potential sites for these progenitor cells are the fetal liver and the embryonic yolk sac. Our studies focus on the yolk sac, both because the yolk sac appears earlier than any other proposed site, and because the mammalian yolk sac is the first site of hematopoiesis. Although it has been shown that the yolk sac in midgestation contains stem cells that can enter the thymic rudiment and differentiate toward T-cell lineage, our aim was to analyze the developmental potential of cells in the yolk sac from earlier stages, prior to the formation of the liver and any other internal organ. We show here that the yolk sac from 8- and 9-day embryos (2–9 and 13–19 somites, respectively) can reconstitute alymphoid congenie fetal thymuses and acquire mature T-cell-specific characteristics. Specifically, thymocytes derived from the early embryonic yolk sac can progress to the expression of mature T lymphocyte markers including CD3/T-cell receptor (TCR), CD4 and CD8. In contrast, we have been unable to document the presence of stem cells within the embryo itself at these early stages. These results support the hypothesis that the stem cells capable of populating the thymic rudiment originate in the yolk sac, and that their presence as early as at the 2-to 9-somite stage may indicate that prethymic stem cells found elsewhere in the embryo at later times may have been derived by migration from this extra-embryonic site. Our experimental design does not exclude the possibility of multiple origins of prethymic stem cells of which the yolk sac may provide the first wave of stem cells in addition to other later waves of cells.

The primary purpose of this study has been to validate the in vitro graft-vs.-host reaction as an experimental system. Time-dose studies have been presented for cells obtained from spleen, thymus, cortisone-treated thymus, inguinal lymph node, mesenteric lymph node, thoracic duct, and bone marrow cells. Both the degree of splenomegaly and the onset of spleen enlargement were found to be dependent on the number and source of cells tested. The effect of several immunosuppressive agents was examined. Amantadine was found to suppress completely the graft-vs.-host reaction in vitro when present at a concentration of 75 µg/ml. Pretreatment of effector cells with mitomycin C prevented their subsequent ability to cause a graft-vs.-host reaction. The effect of X irradiation on immunocompetence of spleen cells in vitro paralleled the known effect of irradiation on in vivo immunocompetence. Preimmunization did not increase the number or effectiveness of immunocompetent cells when measured under standard in vitro conditions. Preimmunization did, however, permit persistence of immunocompetence after immunosuppressive doses of X irradiation. Studies using congenic lines, moreover, indicated that the preimmunization effect could be demonstrated in strain combinations differing only in factors determined by the H-2 complex of genes. A weak graft-vs.-host reaction could be detected in strain combinations not involving differences at the H-2 locus. The potential of the in vitro graft-vs.-host reaction as a highly reproducible, quantifiable, internally controlled, and experimentally accessible system for study of such critical problems as cell differentiation and cell interactions is discussed.

1. Critical size analysis of the lymphoid cell populations of the developing chick bursa of Fabricius and thymus indicates that characteristic shifts in cell size distribution, modal cell volume and mean cell volume occur during morphogenesis of these organs. 2. Comparison of bursa and thymus shows that while there are clear differences between the lymphoid cells of these two structures, the pattern of morphogenetic change is similar. 3. 19-nortestosterone injected in low doses can partially inhibit bursal development without affecting thymus morphogenesis. Depending on the age of the embryo at time of injection, however, doses sufficient to produce complete bursal inhibition may also retard thymic morphogenesis. 4. The size differences found between bursal and thymic lymphocytes in the chicken parallel the size differences found between lymph node and thymic lymphocytes in the mouse.

Adult mice injected with a sheep red blood cell hemolysate supernatant fraction were found to have a severely reduced responsiveness to subsequent immunization with sheep red blood cells. The induced unresponsiveness was found to be specific, as tested by reciprocal experiments involving horse and sheep erythrocyte preparations. The tolerogenic material did not appear to be immunogenic.

The restoration of immunological competence to irradiated adult mouse spleen was studied using an in vitro assay system. Competence of the spleen to evoke a graft versus host reaction in vitro was lost upon sublethal irradiation (550 R). Regeneration of immune competence occurred when such spleens were grown for 2–3 days in the presence of thymus tissue, but not when grown in the presence of a variety of other tissues. This thymic activity was demonstrated to occur across an intervening Millipore filter barrier. When lethal doses of irradiation were used, reactivation of immune competence did not occur unless both thymus and bone marrow were present. In this experimental situation the bone marrow appeared to supply the immunocompetent cells.