Clonal isolates of mouse 3T3 cells and primary rat embryo cells, recovered nonselectively after infection by simian virus 40 (SV40), have been tested for tumorigenicity in the immune-deficient nude mice in order to determine the cellular growth properties in vitro specifically correlated with neoplastic growth in vivo. In addition, mouse 3T3 cells transformed by murine sarcoma virus (MuSV, Kirsten strain), and revertants isolated from cells fully transformed by either SV40 or MuSV were also studied. Results suggest that the single cellular property consistently associated with tumorigenicity in nude mice is the acquisition by virus-transformed cells of the ability to proliferate in vitro in the absence of anchorage. Other cellular parameters of virusinduced transformation, such as lack of sensitivity to high cell density and the capacity to grow in low serum concentration, are dissociable from cellular tumorigenicity. This conclusion is supported further by the demonstration that specific selection in vivo for tumorigenic cells from anchorage-dependent cells results in the isolation of anchorage-independent cells. Conversely, a single-step selection in vitro for anchorage-independent cells from nontumorigenic cells results in a simultaneous selection of highly tumorigenic subclones. Infection of susceptible animal cells in vitro by tumor viruses usually results in a spectrum of stable alterations in cellular growth properties, as well as in the appearance of virus-specific antigens in the transformed cells (1). In particular, division in populations of untransformed cells is inhibited by any of the following three environmental constraints: extensive cell-cell contact (2), reduction of serum concentration (3, 4), or deprivation of a solid substrate for cell anchorage (5, 6).Recent results have demonstrated that cellular responses to the experimental parameters which differentiate the normal cell from its transformed counterpart are not coordinately controlled (7,8). Each constraint is the source of a selective assay that yields a different class of transformed cell line. Nonselective transformations of 3T3 mouse cells and of primary rat embryo cells by simian virus 40 (SV40) yielded lines displaying many different transformed phenotypes. While some lines were fully insensitive to each of the three constraints, most transformed lines lost only one or two of these constraints and remained normal for the others. Negative selection of revertant cell lines from a fully transformed 3T3 cell also dissociated these three parameters of growth control (9, 10).These observations suggested to us that not all of the altered cellular growth properties commonly associated with Abbreviations: SV40, simian virus 40; MuSV, murine sarcoma virus, Kirsten strain; RE, rat embryo; ME, mouse embryo. t Present address:

Machine-checked proofs of properties of programming languages have become a critical need, both for increased confidence in large and complex designs and as a foundation for technologies such as proof-carrying code. However, constructing these proofs remains a black art, involving many choices in the formulation of definitions and theorems that make a huge cumulative difference in the difficulty of carrying out large formal developments. The representation and manipulation of terms with variable binding is a key issue.We propose a novel style for formalizing metatheory, combining locally nameless representation of terms and cofinite quantification of free variable names in inductive definitions of relations on terms (typing, reduction, . . . ). The key technical insight is that our use of cofinite quantification obviates the need for reasoning about equivariance (the fact that free names can be renamed in derivations); in particular, the structural induction principles of relations defined using cofinite quantification are strong enough for metatheoretic reasoning, and need not be explicitly strengthened. Strong inversion principles follow (automatically, in Coq) from the induction principles. Although many of the underlying ingredients of our technique have been used before, their combination here yields a significant improvement over other methodologies using first-order representations, leading to developments that are faithful to informal practice, yet require no external tool support and little infrastructure within the proof assistant.We have carried out several large developments in this style using the Coq proof assistant and have made them publicly available. Our developments include type soundness for System F<: and core ML (with references, exceptions, datatypes, recursion, and patterns) and subject reduction for the Calculus of Constructions. Not only do these developments demonstrate the comprehensiveness of our approach; they have also been optimized for clarity and robustness, making them good templates for future extension.

Let r : G_Q -> GL_2(Fpbar) be a p-ordinary and p-distinguished irreducible residual modular Galois representation. We show that the vanishing of the algebraic or analytic Iwasawa mu-invariant of a single modular form lifting r implies the vanishing of the corresponding mu-invariant for all such forms. Assuming that the mu-invariant vanishes, we also give explicit formulas for the difference in the algebraic or analytic lambda-invariants of modular forms lifting r. In particular, our formula shows that the lambda-invariant is constant on branches of the Hida family of r. We further show that our formulas are identical for the algebraic and analytic invariants, so that the truth of the main conjecture of Iwasawa theory for one form in the Hida family of r implies it for the entire Hida family

In this paper we study the two p-adic L-functions attached to a modular form f = a n q n at a supersingular prime p. When a p = 0, we are able to decompose both the sum and the difference of the two unbounded distributions attached to f into a bounded measure and a distribution that accounts for all of the growth. Moreover, this distribution depends only upon the weight of f (and the fact that a p vanishes). From this description we explain how the p-adic L-function is controlled by two Iwasawa functions and by two power series with growth which have a fixed infinite set of zeros (Theorem 5.1). Asymptotic formulas for the p-part of the analytic size of the Tate-Shafarevich group of an elliptic curve in the cyclotomic direction are computed using this result. These formulas compare favorably with results established by M. Kurihara in on the algebraic side. Moreover, we interpret Kurihara's conjectures on the Galois structure of the Tate-Shafarevich group in terms of these two Iwasawa functions.

The patterns of distribution of intracellular actin and myosin were examined by specific immunofluorescence in a series of normal, simian-virus-40-transformed, and revertant cell lines of rat and mouse origin. A consistent correlation was found between sensitivity to anchorage-dependent growth control and the presence of large, thick sheaths of actin-containing material. The presence of these sheaths was temperature-dependent in a rat line transformed by a temperature-sensitive mutant in the complementation group A of the oncogenic virus simian virus 40.Many changes in cell structure, such as cell movement, ruffling, and cytokinesis, can be traced to contractions. These changes very likely occur by the contraction of intracellular actomyosin (1-3), in which the actin is very similar or identical to muscle actin (2, 4-6) and the myosin is similar to the myosin in smooth muscle (7,8) and platelets (9, 10).Microfilaments (6 nm), but not other intracellular fibers, bind heavy meromyosin (4,11,12), which demonstrates that they contain actin. Microfilaments are arrayed in at least two distinct configurations in the normal migrating fibroblastic cell: as a 3-dimensional matrix about 100 nm thick, just under the cell membrane, and in subcortical sheaths (11,(13)(14)(15)(16)(17). In flattened cells, the sheaths (also called stress fibers) run along the bottom and out into the edges of a cell (13,(18)(19)(20).Recently, the preparation of an antibody directed specifically against actin permitted an examination by immunofluorescence of the localization of actin in normal cultured 3T3 cells (21). Actin was found to occur predominantly in the form of long and thick sheaths in a variety of non-transformed cells of different species (21). In the case of well-spread mouse 3T3 cells, these sheaths correspond to "stress fibers" seen in phase microscopy and are related to the thick bundles of microfilaments seen in electron microscopy (22). Myosin also has been visualized by immunofluorescence, using antibody to chick smooth muscle myosin (23). These studies have revealed that myosin in well-spread mouse 3T3 cells is arranged in striated structures, which seem to be related to, if not identical to, the thick actin-containing fibers. However, presence of myosin in a less structured organization, possibly outside the thick phase dense fibers, was also indicated (23).Previously several electron microscopic studies have indicated that the transformed state is accompanied by a less Abbreviations: SV40, simian virus 40; RE, rat embryo; WT, wild type.