Effect of tyrphostins on programmed cell death in colon adenocarcinoma cell line LS-180

Programmed cell death is an important process in the regulation of cellular proliferation, rest, differentiation and death. It is a genetically controlled process with characteristic biochemical and morphological features. Apoptosis directly regulates tumorigenesis and its induction could be a useful method of cancer therapy. Cancer cells could be influenced by some factors which induce apoptosis. We investigated the influence of tyrphostins, that specifically inhibits protein tyrosine kinases and stops the cell cycle in apoptosis of the colon adenocarcinoma cell line LS180. We used them at the concentration of 1-10 microM for 24 and 48 hours. We detected apoptosis using techniques that monitor either biochemical and morphological features of this process, such as staining with 7-amino-actinomycin D, staining with Grünwald-Giemsa, TUNEL reaction, in situ hybridization and with immunoperoxidase staining procedures. We examined the expression of genes and proteins connected with programmed cell death (p53, c-myc, p21, bcl-2). We estimated the results by cytophotometry and documented them by colour photography. We found that tyrphostin rapidly inhibits the cell cycle, particularly at the concentration of 5 microM. The expression of genes and proteins was strongly correlated with the increased apoptotic cell death conforming to the results of TUNEL and staining methods.     

Label-free FTIR spectroscopy detects and visualizes the early stage of pulmonary micrometastasis seeded from breast carcinoma

An application of FTIR spectroscopic imaging for the identification and visualization of early micrometastasis from breast cancer to lungs in a murine model is shown. Spectroscopic and histological examination is focused on lung cross-sections derived from animals at the early phase of metastasis (early micrometastasis, EM) as compared to healthy control (HC) and late phase of metastasis (advanced macrometastasis, AM) using murine model of metastatic breast cancer with 4T1 cells orthotopically inoculated. FTIR imaging allows for a detailed, objective and label-free differentiation and visualization of EM foci including large and small micrometastases as well as single cancer cells grouped in clusters. An effect of the EM phase on the entire lung tissue matrix as well as characteristic biochemical profiles for HC and advanced macrometastasis were determined from morphological and spectroscopic points of view. The extraordinary sensitivity of FTIR imaging toward EM detection and discrimination of AM borders confirms its applicability as a complementary tool for the histopathological assessment of the metastatic cancer progression.     

Properties of maximal spacing on a circle related to phyllotaxis and to the golden mean

A class of divergence angles φ_G of phyllotaxis is defined that distribute leaves about the stem of a plant in a more uniform manner than do nearby angles. A theorem of Swierczkowski concerning the intervals between adjacent points placed on a circle according to the divergence angle 137·5° is generalized to include the other angles encountered in phyllotaxis. These angles are characterized by having continued fraction expansions containing no intermediate fractions after a finite number of terms. This criterion is shown to be sufficient for uniform spacing of leaves.A morphogen concentration field established by the leaves acting as sources is determined principally by :he geometrical spacing of the leaves and hence by their divergence angle. It is shown that the mean square of such a concentration field, is a relative minimum if the leaves are positioned by means of one of the φ_G. Thornley's dynamic scheme for determining the phyllotaxis divergence angles by positioning a new leaf at the minimum of the concentration field of previously placed leaves is also shown to be related to the spacing properties of the φ_G.