A 36-year-old man had chronic, debilitating diarrhea due to cryptosporidiosis. This patient had longstanding common variable hypogammaglobulinemia and recurrent bacterial infections. Immunologic evaluation after discovery of Cryptosporidium showed lymphopenia with persistently reduced numbers of helper/inducer cells (OKT-4), variable numbers of suppressor/cytotoxic cells (OKT-8), OKT-4/OKT-8 ratio of 0.09, and increased levels of serum alpha-interferon, all of which describe the acquired immunodeficiency syndrome. Oocysts of Cryptosporidium were found in feces from the patient's cat, thus identifying a possible source of his infection. The patient had disseminated candidiasis, cytomegalovirus pneumonia, and cryptosporidiosis when he died.
The presence of cellular heterogeneity within human tumors has been recognized for many years. Current concepts regarding the clonal origin of human neoplasms, and recent advances in the study of successive genetic changes that occur during tumor evolution may now make it possible to understand in greater depth the biological and clinical implications of intra-tumor heterogeneity at both the phenotypic and genotypic levels. In order to explore these concepts further, and to better identify the potential contributions that flow and image cytometry can make to our understanding of tumor heterogeneity, a session of the 1994 ISAC Congress was dedicated to plenary presentations on human cancer cell heterogeneity. Here, we provide a brief overview of the genetic evolutionary progression of human cancers, some considerations of clinically important phenotypic and genotypic markers, and an outline that might serve as a basis for framing relevant issues that are ammenable to further study.All Nature is but Art, unknown to thee; All Chance, Direction, which thou canst not see; All Discord, Harmony not understood: All partial Evil, universal Good. (Alexander Pope, Essay on Man, end of Epistle 1) 0 I995 Wilcy-Liss, Inc.
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