The polypeptide cytokine interleukin-1 (IL-1) affects nearly every tissue and organ system. IL-1 is the prototype of the pro-inflammatory cytokines in that it induces the expression of a variety of genes and the synthesis of several proteins that, in turn, induce acute and chronic inflammatory changes. IL-1 is also the prototypic "alarm" cytokine in that it brings about increases in a variety of defense mechanisms, particularly immunologic and hematologic responses. Most studies on the biology of IL-1 have been performed in animals, but human subjects have recently been injected with recombinant IL-1 and the results confirm the two fundamental properties of IL-1 as being both a mediator of disease as well as of host defense. However, in either situation, over or continued production of IL-1 leads to debilitation of normal host functions; therefore, reduction of IL-1 synthesis or its effects becomes a target of therapy in many diseases. In this review, the structure, gene expression, synthesis, and secretion of IL-1 are described. In addition, the two IL-1 surface receptors, possible signal transduction mechanisms, various biologic activities, and production of IL-1 during disease states are discussed. Similarities and differences between IL-1, tumor necrosis factor, and IL-6 are presented. Although various agents for reducing the synthesis and/or for antagonizing the effects of IL-1 have been proposed, the recent cloning of a naturally occurring IL-1 receptor antagonist (IL-1ra) has opened new experimental and clinical approaches. The ability of this IL-1ra to block the triggering of IL-1 receptors in animals without agonist effects has reduced the severity of diseases such as hemodynamic shock, lethal sepsis, inflammatory bowel disease, experimental arthritis, and the spontaneous proliferation of human leukemic cells.

Bleeding after CPB has been difficult to characterize and its treatment equally difficult to standardize. The complexity of this problem is related to the hemostatic process, the technical variations in the operative procedures, and the many uncontrolled variables associated with CPB, including the effects of anesthetic or pharmacologic agents, the nature of the priming solution, hemodilution, hypothermia, the type of oxygenator, and the use of transfused blood products. Although there are multiple and generally predictable complex changes in the hemostatic mechanism during CPB, the temporary loss of platelet function is the most common and clinically relevant. This transient platelet dysfunction occurs in all patients undergoing CPB; however, it only causes excessive bleeding in a small percentage of patients. Unfortunately, it has not yet been possible to predict which patients will develop hemorrhagic complications, although prolonged pump times are a contributing risk factor. Over the past decade there has been extensive investigation into the management of bleeding associated with CPB, provoked primarily by the increased awareness of transfusion-transmitted viral diseases and the inappropriately excessive use of homologous blood products. Several approaches to autotransfusion of shed blood and autologus blood donation have been developed to minimize perioperative homologous blood transfusion. Pharmacologic agents such as desmopressin, aprotinin, and topical fibrin glues have also been introduced to improve hemostasis during CPB. The protease inhibitor aprotinin is particularly promising in the reduction of bleeding associated with CPB when given prophylactically. Aprotinin may provide new insights into the mechanism of CPB-induced platelet dysfunction. Desmopressin is indicated only for the treatment of bleeding after CPB. The management of bleeding associated with CPB will undoubtedly

Virtually all cases of childhood ALL have chromosomal abnormalities and half contain translocations, which are nearly equally divided between random and nonrandom rearrangements. Nonrandom chromosomal abnormalities have been correlated with leukemic cell lineage, the degree of cell differentiation, and the specific gene involved at the molecular level. Many cytogenetic findings have prognostic significance; however, the adverse influence of certain changes, including most chromosomal translocations, may in fact be offset by the greater cytoreductive effects of intensified therapy. Table 4 summarizes the relation of selected karyotypic findings to treatment outcome in patients treated on contemporary protocols. Among all of the chromosomal abnormalities identified in childhood ALL, hyperdiploidy greater than 50 has been associated with the most favorable prognosis. At the opposite end of the spectrum, the treatment outcome for patients with classical Ph+ or hypodiploid ALL is very poor even in programs of intensive chemotherapy; alternative treatment such as bone marrow transplantation should be considered for such patients. Cases with the t(4;11)(q21;q23) also have a very poor clinical outcome, but the adverse prognosis may be limited to the infant or adolescent age groups. The prognostic significance of other nonrandom translocations, such as t(1;19)(q23;p13) and several other abnormalities, needs to be further assessed in larger numbers of patients. Finally, as more is learned about the molecular pathology underlying these rearrangements, it may be possible to develop new therapeutic agents that are specifically targeted to interfere with the aberrant gene products expressed by human leukemic cells.