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Rhim and Kremer’s state-of-the-art volume on Human Cell Transformation: Role of Stem Cells and the Microenvironment highlights the latest findings on the current state of human cell transformation model systems and provides the insight into the molecular and cellular changes involved in the conversion of normal cells to neoplastic cells. Chapters cover all recently developed novel human cell models. In addition, the rapidly growing fields of knowledge regarding not only stem cells in cancer progression, but also the role of the microenvironments in human carcinogenesis are discussed. A wealth of topics is presented including: · Derivation of epithelial, fibroblastic, and hematopoietic in vitro model systems · Oncogenes · Tumor suppressor genes · Viral transformation · In vitro model systems for viral, chemical and radiation carcinogenesis · Cell aging · The multistep nature of human carcinogenesis · The role of stem cells and the microenvironment in tumorigenesis · The genes involved in multistep carcinogenesis Unique in both scope and focus – devoted solely to human cell transformation systems – Human Cell Transformation: Role of Stem Cells and the Microenvironment provides unparalleled, in-depth coverage for cancer researchers, cell and molecular biologists, hematologists, virologists, and workers in related fields. Essential reading for everyone who needs to be kept up-to-date in this fast-paced area! Features ؠ Multistep models ؠ Breast cancer/Stem cells ؠ Prostate cancer/Stem cells ؠ Multistep / Genes

This book provides critical reviews regarding the process of somatic hypermutation in antibody V genes. Topics covered include the in vivo kinetics of antigen-driven somatic hypermutation in a number of well-studied systems in mice; the instability of lg genes in cultured cells; the key role played in vivo by germinal centers in providing the appropriate "mutational" microenvironment; the types of nucleotide sequence errors generated; the process of hypermutation in pre-arranged V regions expressed in transgenic mice; and a critical evaluation of the status of molecular models proposed to explain hypermutation. Other topics include a detailed review of data from hypervariable retroviral systems, as well as precise studies on the mutagenic potential of various DNA polymerases in vitro. The book will provide indispensable information for immunologists, geneticists, molecular biologists, biochemists, and cell biologists.

The inflorescence of the monoecious maize plant is unique among the Gramineae in the sharp separation of the male and female structures. The male tassel at the terminus of the plant most often sheds pollen before the visual appearance of the receptive silks of th the female ear at a lateral bud, normally at the 10 leaf [I]. Earlier studies examined the ontogeny of the growing tissues beginning with the embryo in the kernel through to the obvious protuberances of the growing point as the kernel germinates. The differentiated developing soon-to-become tassel and the lateral bulges that develop into the ears on the lateral buds become apparent very early in the germinating kernel [2, 3, 46]. A certain number of cells are destined for tassel and ear development [8]. As the plant develops, there is a phase transition [\3, 16] from the vegetative lateral buds to the reproductive lateral buds. This change in phase has been ascribed to genotypic control as evidenced in the differences among different genotypes in the initiation of the reproductive [I]. The genetic control of tassel and ear initiation has been gleaned from anatomical observations. Lejeune and Bernier [I2] found that maize plants terminate the initiation of additional axillary meristems at the time of tassel initiation. This would indicate that the top-most ear shoot is initiated on the same day as the initiation of tassel development and this event signals the end of the undifferentiated growing point.

Recent progress in fundamental tumor immunology has led to immunotherapy trials in patients with solid tumors and hematological malignancies. In the past, immunotherapy approaches were primarily based on enhancement of tumor immunity with cytokines and adjuvant therapy, without knowledge of relevant tumor antigens. The discovery of tumor antigens c

Cytogenetics of Cells in Culture is a compendium of papers that deals with techniques to detect patterns of DNA replication, cellular control mechanisms, and chromosome analyses with automated instrumentation. Some papers discuss the effects of cell hybridization and of noxious substances such as radiation, chemical agents, and viruses on chromosomal patterns. Other papers focus on the influence of altered chromosomal complement on the survival of cells to long-term tissue culture or to ionizing radiation treatment. A couple of papers points out that naturally occurring chromosomal abnormalities in mammalian populations are relatively rare and are not necessarily associated with physical defects or disease. One paper notes that chromosomes in cells with different functions have different patterns of replication in which the changes are small and hidden. The chromosomes will usually be neutralized showing little of the characteristic pattern of replication or condensation during the early cleavage stages, that will later change into differentiated characteristic ways for each tissue type. Another paper describes chromosome breakage associated with viruses and DNA inhibitors. The compendium can prove beneficial for biochemists, micro-biologists, cellular researchers, and academicians involved in the study of cellular biology or physiology.

Because of several valid (and some invalid) reasons, the research field of tumor immunology has been declining in popularity. The Simplistic dogmas, articles of faith, and theories of the late 1960s and early 1970s on the immuno logical mechanisms of the host-tumor interrelationships have frequently been refuted by some of the new developments in cancer biology, cancer biochem istry, and immunology. Furthermore, some of the conventional assays used to monitor "tumor-host immune relations" did not always reflect the host's true clinical situation or his prognosis. Several approaches to immunological interven tion were less successful than expected. In addition, the concept of "immune surveillance," which was basic to many researchers in the field of cancer im munology, seemed to fall apart. Much of the criticism was based on results from solid, well-performed, and well-controlled experiments, but there was also un just criticism based on ill-conceived and badly performed studies, and on misin terpretations of experimental data. There are many misconceptions about the tumor-host relationship. It is very often assumed that tumor immunity, as expressed systemically, is truly reflected at the tumor site. Several studies reported in this volume and elsewhere indicate that such is not always the case. Certain immune effectors may be selectively prevented from reaching the tumor site or the close vicinity of the tumor cells because of mechanical or chemical barriers, whereas others may be selectively attracted to the site by chemotaxis or other mechanisms.