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[en] Tumor vascularization is characterized by many morphological peculiarities and hemodynamic abnormalities which result in chronic or acute hypoxia of tumor cells. Radioresistance of these cells is a major problem in radiotherapy and many therapeutic failures may be attributed to inadequate sterilization of hypoxic cells. Efficient use of therapeutic approaches is greatly limited by the lack of information on the proportion of hypoxic cells in different tumours. Quantitative estimation of intra- and intertumor variances of vascularization in biopsy specimens, by defining a vascularity index, would better characterize individual tumors and select appropriate therapeutic approaches. (author)
[en] Baker and others developed an adhesive tumour cell culture system (ATCCS) using a culture surface coated with a cell attachment matrix (CAM). The ability of CAM-coated plates to support the growth of cells from human tumour biopsies has been evaluated. Successful growth was obtained in 9/22 samples (41 percent), but fibroblasts, rather than tumour cells, grew in the majority. Comparison of CAM with other surfaces showed that CAM was no better for establishing tumour cell growth than the presence of feeder cells or an alternative attachment factor vitronectin. (author). 12 refs.; 2 tabs
[en] Histological analysis conducted on somatic embryos of Eurycoma longifolia shows the developmental structures that are remarkably similar to seeds found in the wild. The primary components of a growing somatic embryo are its shoot and root apical meristems indicated by dense layers of rapidly growing cells. The increased understanding of In vitro culture systems and anatomical changes provide information into cellular processes that govern genetic transformation of E. longifolia with Agrobacterium rhizogenes. The presence of meristematic regions on cultured somatic embryos suggests that they are suitable for genetic transformation as genetic elements could be transported to these regions where growth and differentiation are centered. This allows the successful integration and expression of transferred DNA in the host organism, leading the way for an efficient A. rhizogenes-mediated transformation protocol. (author)
[en] Down-regulation of transcription of the MHC class I genes in HPV16 tumorigenic cells is partly due to HPV16E7 associated with the MHC class I promoter and repressed chromatin activation. In this study, we further demonstrated that HPV16E7 is physically associated with a putative RXRβ binding motif (GGTCA) of the proximal promoter of the MHC class I genes by using reporter transcriptional assays and chromatin immunoprecipitation assays. Our data also provide evidence that HPV16E7 inhibits TNF-α-induced up-regulation of MHC class I transcription by impaired nuclear translocation of NF-κB. More importantly, CaSki tumor cells treated with TSA and transfected with the constitutively active mutant form of IKK-α (which can activate NF-κB directly) showed a maximal level of up-regulation of MHC-I expression. Taken together, our results suggest that HPV16E7 may employ two independent mechanisms to ensure that either the constitutive or inducible transcription of MHC class I genes is down-regulated.
[en] After establishing the immuno-cytochemical staining technique of cell samples suitable for soft X-ray contact microscopy (SXCM), the HLA-A2 surface antigens of cultured Hep-2 tumor cells were labelled by immuno-gold silver staining (IGSS) and detected by SXCM. The results reveal that the immuno-gold silver granules on the surface of Hep-2 tumor cells have sharp contrast and show stereo features, and the granules with different sizes and shapes can be clearly seen and easily identified
[en] The EGF promotes inhibition of cell proliferation in vitro and in vivo models depending on its concentration, application schema and the type of tumor cells on which it acts. Our research hypothesis was based on the fact that the EGF varies the expression of genes involved in a negative regulation of tumor cell lines proliferation carrying high levels of its receptor (EGFR). Our objectives were, to obtain information about the effect of EGF on tumor cell proliferation in vitro and in vivo models and, know the gene expression patterns of a group of genes involved in cancer signaling pathways and EGFR. The results showed that EGF at nanomolar concentrations inhibits the tumor cells proliferation bearing high levels of EGFR and, promotes the survival of treated animals, establishing a direct relationship between the inhibition of cell proliferation, high concentrations of EGF and, high amount of EGFR in the cells. The differential gene expression profile showed a variation in a group of genes which exert a powerful control over the cell cycle progression, gene transcription and apoptosis. It was concluded that the inhibition of tumor cell proliferation by the action of EGF is due to activation of molecular mechanisms controlling cell cycle progression. This work won the Annual Award of the Cuban Academy of Sciences in 2012
[en] 81Rb is produced in high specific activity and yield by the reaction 79Br(α,2n)81Rb. The 81Rb is purified and absorbed on an ion-exchange column in a minigenerator, which allows the elution, at a rapid rate, of the /SUP 81m/Kr daughter in a biologically compatible, sterile solution. Applications of /sup 81m/Kr are described. Chemical binding in tumor cells is being studied and the use of /sup 134m/Cs for myocardial scanning is being evaluated. (U.S.)
[en] A nonlinear age-structured tumor cell population model is presented and analyzed. The population is divided into proliferating and quiescent cell compartments. The nonlinearity of the birth rate is designed to halt population’s exponential growth and force the system to converge to stable equilibria or stable cycles. The existence and uniqueness of solutions are studied. The local and global stabilities of the trivial steady state are investigated. Moreover, the existence and local stability of the positive steady state are analyzed. Numerical examples are performed to verify the validity of the results and to discuss the impacts of parameters on the nonlinear dynamics of the model.
[en] Lenalidomide is an amino-substituted derivative of thalidomide with direct antiproliferative and cytotoxic effects on the myeloma tumor cell, as well as antiangiogenic activity and immunomodulatory effects. Together with the introduction of bortezomib and thalidomide, lenalidomide has significantly improved the survival of patients with relapsed and refractory myeloma. The most common adverse events associated with lenalidomide include fatigue, skin rash, thrombocytopenia, and neutropenia. In addition, when lenalidomide is combined with dexamethasone or other conventional cytotoxic agents, there is an increase in the incidence of venous thromboembolic events. There is now evidence that continued treatment with lenalidomide has a significant impact on survival by improving the depth and duration of response. This highlights the value of adverse event management and appropriate dose adjustments to prevent toxicity, and of allowing continued treatment until disease progression. In this review, we will discuss the different lenalidomide-based treatment regimens for patients with relapsed/refractory myeloma. This is accompanied by recommendations of how to manage and prevent adverse events associated with lenalidomide-based therapy
[en] The author tries to assess whether studies of the influence of radiation quality yield insight into causes of differences in radiosensitivity as observed between cell types and between cells in different phases of the mitotic cycle. The linear-quadratic equation is discussed and the usefulness of analysing normal-tissue responses in predicting clinical tolerance and tumor cell response. (UK)