The cytoskeleton in cultured cells: coordinate in vitro regulation of cell growth and shape

Adenopolyposis of the colon and rectum (ACR) links the well-characterized phenomena of murine oncogenic virus transformation with the progression of a human cancer. The same syndrome links defects in fibroblast growth control and cytoskeletal organization to a tumor of epithelial origin. Since skin fibroblasts are involved in this colonic tumor, the syndrome is very likely to be systemic. That is, one element of normal growth regulation of epithelial cells in situ may be provided by the fibroblasts residing beneath their basement membrane. These observations have led to a novel approach to early detection of persons at risk for a tumor, via the behavior of their skin fibroblasts in culture. At present, it is rarely possible to detect persons at risk for malignancy before the appearance of a frank invasive or metastatic growth. Although many biochemical assays have been proposed as indicators of pre-malignant states or cryptic early tumors, most have eventually been shown to be related to age, sex drug treatment, or other variables linked to but not clearly indicative of, a malignancy. Two serious problems limiting attempts to detect preneoplastic states or a disposition to eventual neoplasia are the inherent low frequency of incidence of any single type of tumor and the difficulty of obtaining identical sample material from prospective or actual patients once they are located. Our approach to these problems significantly departs from the common dependence upon isolation of cells from the site of a tumor. Clearly, it is an easier task to scan skin fibroblasts for disrupted cytoskeletal patterns than it is to obtain epithelia cells from most tissues at high risk for malignancy. This line of work, buttressed by information derived from the model system of SV40 transformation, may provide a novel mode of early detection of other human malignancies, as it has for ACR

Asymptotic behaviour of the total cross section of p-p scattering and the Akeno cosmic ray data

I present a new determination of the total cross section for proton-proton collisions from the recent Akeno results on absorption of the cosmic ray protons in the p-Air collisions. Extrapolation to the SSC energy suggests $\sigma_{tot}(p-p) \approx (160-170) mb$. I also comment on a possible sensitivity of the p-Air cross section determinations to assumptions on the inelasticity of nuclear collisions at high energy.Comment: . 6 pages, 0 figure

Induction of Metastatic Gastric Cancer by Peroxisome Proliferator-Activated Receptorδ Activation

Peroxisome proliferator-activated receptorδ (PPARδ) regulates a multiplicity of physiological processes associated with glucose and lipid metabolism, inflammation, and proliferation. One or more of these processes likely create risk factors associated with the ability of PPARδ agonists to promote tumorigenesis in some organs. In the present study, we describe a new gastric tumor mouse model that is dependent on the potent and highly selective PPARδ agonist GW501516 following carcinogen administration. The progression of gastric tumorigenesis was rapid as determined by magnetic resonance imaging and resulted in highly metastatic squamous cell carcinomas of the forestomach within two months. Tumorigenesis was associated with gene expression signatures indicative of cell adhesion, invasion, inflammation, and metabolism. Increased PPARδ expression in tumors correlated with increased PDK1, Akt, β-catenin, and S100A9 expression. The rapid development of metastatic gastric tumors in this model will be useful for evaluating preventive and therapeutic interventions in this disease

DIPSI: a Monte Carlo generator for elastic vector meson production in charged lepton-proton scattering

We present a Monte Carlo generator for exclusive vector meson production in charged lepton-proton interactions, l+p --> l+p+V, based on a QCD leading logarithm model calculation according to which the cross section for this process is proportional to the square of the gluon momentum density in the proton. The generator can be used for both fixed target and collider kinematics. Each event is assigned a weight equal to its cross section, so that the independent variables can be generated according to convenient distributions, not necessarily identical to the physics ones.Comment: 24 pages, 7 figures, Latex, to be published in Computer Physics Communication

Diffractive Dissociation and Eikonalization in High Energy pp and p pˉ {\bar p} Collisions

We show that eikonal corrections imposed on diffraction dissociation processes calculated in the triple Regge limit, produce a radical change in the energy dependence of the predicted cross section. The induced correction is shown to be in general agreement with the new experimental data measured at the Tevatron.Comment: 11 pages LATEX, ( two figures not included obtainable from authors) (TAUP 2066-93 and FERMILAB PUB 93/ T