224 research outputs found

    Planeamiento estratégico para el sector de biocombustibles en Colombia

    Get PDF
    A 2013, el sector de los biocombustibles en Colombia se ha convertido en uno de los sectores más importantes en el desarrollo agrícola del país, no solo por la intención del Gobierno de mezclar combustibles fósiles con biocombustibles, sino también por el impacto social que tiene en las diferentes regiones agrícolas. En el presente planeamiento estratégico del sector, se han analizado diferentes aspectos internos y externos, a los que posteriormente se les plantearon las estrategias con los objetivos a largo y corto plazo, con los cuales se lograrán los crecimientos y las metas planteadas en la visión que está proyectada a 2020. Al inicio se describió la situación actual de Colombia y del sector de combustibles a nivel mundial, regional, y nacional, luego sus antecedentes y se plantearon la visión, misión, los valores, y código de ética del mismo. Posteriormente, se realizó la evaluación externa a través del análisis tridimensional de las naciones, el análisis competitivo del sector, y el análisis PESTE; luego la evaluación interna a través del análisis AMOFHIT. Se compararon los intereses del sector y los objetivos a largo plazo, posteriormente dentro del proceso estratégico se desarrollaron las matrices. Como resultado de la planeación se propusieron cuatro objetivos a largo plazo y seis estrategias para el sector relacionadas con penetración de productos, desarrollo de nuevos mercados, integración horizontal, y alianzas estratégicas. Sigue la implementación estratégica; donde los planes se vuelven acciones para lograr los objetivos, y se medirá y revisará el cumplimiento de las metas a través del Tablero de Control Integrado, lo que permitirá que se realicen acciones correctivas de ser necesario. Al final, se determinan las conclusiones, las recomendaciones, y el futuro del sector de biocombustibles en Colombia a 2020.On the last few years, the Biofuels sector in Colombia has become one of the most important sectors in the agriculture development of the country. Not only due to the intention of the government to mix Biofuels with fossil fuels, but also because of the high social impact that it represents for agricultural regions. The present strategic plan for the Colombian Biofuel sector has analyzed different internal and external factors, and proposes strategies with long and short term objectives that promote growth and the targets established for the 2020 vision. The present plan starts with a description of Colombia’s and global´ s current fuel background, with national and regional analysis; we state a vision, mission, values and ethical code for the Colombian biofuels sector. We proceed with the external evaluation through the analysis in three different dimensions, the competitive analysis of the sector, the PESTE analysis and the internal evaluation based on the AMOFHIT research. Then we compare the interests of the sector and the long terms objectives. As a result of the strategic planning process, we developed four long term objectives and six different strategies for the sector related to product penetration, new market developments, horizontal integration and strategic joint ventures. We continue the analysis with the strategic implementation, where the plans become actions in order to achieve the targets. These must be measured and revised in order to accomplish the goals using the balance score card, which must generate corrective actions if it´s necessary. We complete the analysis with the conclusions, recommendations and the possible future of the Biofuel sector in Colombia for 2020.Tesi

    Polymorphisms in the CD28/CTLA4/ICOS genes: Role in malignant melanoma susceptibility and prognosis?

    Get PDF
    The appearance of vitiligo and spontaneous regression of the primary lesion in melanoma patients illustrate a relationship between tumor immunity and autoimmunity. T lymphocytes play a major role both in tumor immunity and autoimmunity. CD28, Cytotoxic T lymphocyte antigen 4 (CTLA4) and inducible costimulator (ICOS) molecules are important secondary signal molecules in the T lymphocyte activation. Single nucleotide polymorphisms (SNPs) in the CD28/CTLA4/ICOS gene region were reported to be associated with several autoimmune diseases including, type-1 diabetes, SLE, autoimmune thyroid diseases and celiac disease. In this study, we investigated the association of SNPs in the CD28, CTLA4 and ICOS genes with the risk of melanoma. We also assessed the prognostic effect of the different polymorphisms in melanoma patients. Twenty-four tagging SNPs across the three genes and four additional SNPs were genotyped in a cohort of 763 German melanoma patients and 734 healthy German controls. Influence on prognosis was determined in 587 melanoma cases belonging to stage I or II of the disease. In general, no differences in genotype or allele frequencies were detected between melanoma patients and controls. However, the variant alleles for two polymorphisms in the CD28 gene were differentially distributed in cases and controls. Similarly no association of any polymorphism with prognosis, except for the rs3181098 polymorphism in the CD28 gene, was observed. In addition, individuals with AA genotype for rs11571323 polymorphism in the ICOS gene showed reduced overall survival. However, keeping in view the correction for multiple hypothesis testing our results suggest that the polymorphisms in the CD28, CTLA4 and ICOS genes at least do not modulate risk of melanoma and nor do those influence the disease prognosis in the investigated population

    Outcome After Therapeutic Lymph Node Dissection in Patients with Unknown Primary Melanoma Site

    Get PDF
    Purpose: The aim of this study was to evaluate the incidence and outcome of melanoma of unknown primary site (MUP) after therapeutic lymph node dissection (TLND) of palpable nodal melanoma metastases. Disease-free (DFS) and overall survival (OS) time of MUP patients were analyzed and compared to patients undergoing a TLND for known primary melanomas (MKP). Methods: This single institution retrospective study analyzed 342 consecutive patients who were treated with 415 TLNDs for palpable nodal disease from 1982 to 2009. Univariate and multivariate analyses included: MUP versus MKP, gender, Breslow thickness, ulceration of primary tumor, site of prima

    Role of oxidative stress and intracellular glutathione in the sensitivity to apoptosis induced by proteasome inhibitor in thyroid cancer cells

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The proteasome inhibitor bortezomib has shown impressive clinical activity alone and in combination with conventional and other novel agents for the treatment of multiple myeloma (MM) and some solid cancers. Although bortezomib is known to be a selective proteasome inhibitor, the downstream mechanisms of cytotoxicity and drug resistance are poorly understood.</p> <p>Methods</p> <p>Proteasome activity, intracellular glutathione (GSH) and ROS levels, as well as activities of GSH synthesis enzymes were measured using spectrophotometric methods. Cell death was analyzed using flow cytometry and caspase activity assay. The expression level of GSH synthesis enzymes were measured using real-time RT-PCR.</p> <p>Results</p> <p>At concentrations that effectively inhibited proteasome activity, bortezomib induced apoptosis in FRO cells, but not in ARO cells. Bortezomib elevated the amount of glutathione (GSH) and the treatment with bortezomib increased the level of mRNA for GCL, a rate-limiting enzyme in glutathione synthesis. Furthermore, depletion of GSH increases apoptosis induced by bortezomib, in contrast, repletion of GSH decreases bortezomib-mediated cell death.</p> <p>Conclusion</p> <p>GSH protects cells from proteasome inhibition-induced oxidative stress and glutathione-dependent redox system might play an important role in the sensitivity to proteasome inhibition-induced apoptosis.</p

    Targeting BRAF for patients with melanoma

    Get PDF
    The prognosis of patients with metastatic melanoma is poor and not influenced by systemic therapy with cytotoxic drugs. New targeted agents directed against the RAS-RAF-MEK-ERK pathway show promising activity in early clinical development and particular interest is focused on selective inhibitors of mutant BRAF, which is present in one half of the cases of metastatic melanoma. The majority of patients on early trials of these drugs develop secondary resistance and subsequent disease progression and it is, therefore, critical to understand the underlying escape mechanisms leading to resistance

    BAY61-3606 Affects the Viability of Colon Cancer Cells in a Genotype-Directed Manner

    Get PDF
    Background: K-RAS mutation poses a particularly difficult problem for cancer therapy. Activating mutations in K-RAS are common in cancers of the lung, pancreas, and colon and are associated with poor response to therapy. As such, targeted therapies that abrogate K-RAS-induced oncogenicity would be of tremendous value. Methods: We searched for small molecule kinase inhibitors that preferentially affect the growth of colorectal cancer cells expressing mutant K-RAS. The mechanism of action of one inhibitor was explored using chemical and genetic approaches. Results: We identified BAY61-3606 as an inhibitor of proliferation in colorectal cancer cells expressing mutant forms of K-RAS, but not in isogenic cells expressing wild-type K-RAS. In addition to its anti-proliferative effects in mutant cells, BAY61-3606 exhibited a distinct biological property in wild-type cells in that it conferred sensitivity to inhibition of RAF. In this context, BAY61-3606 acted by inhibiting MAP4K2 (GCK), which normally activates NFκβ signaling in wild-type cells in response to inhibition of RAF. As a result of MAP4K2 inhibition, wild-type cells became sensitive to AZ-628, a RAF inhibitor, when also treated with BAY61-3606. Conclusions: These studies indicate that BAY61-3606 exerts distinct biological activities in different genetic contexts

    Pan-RAF and MEK vertical inhibition enhances therapeutic response in non-V600 BRAF mutant cells

    Get PDF
    BACKGROUND: Currently, there are no available targeted therapy options for non-V600 BRAF mutated tumors. The aim of this study was to investigate the effects of RAF and MEK concurrent inhibition on tumor growth, migration, signaling and apoptosis induction in preclinical models of non-V600 BRAF mutant tumor cell lines. METHODS: Six BRAF mutated human tumor cell lines CRL5885 (G466 V), WM3629 (D594G), WM3670 (G469E), MDAMB231 (G464 V), CRL5922 (L597 V) and A375 (V600E as control) were investigated. Pan-RAF inhibitor (sorafenib or AZ628) and MEK inhibitor (selumetinib) or their combination were used in in vitro viability, video microscopy, immunoblot, cell cycle and TUNEL assays. The in vivo effects of the drugs were assessed in an orthotopic NSG mouse breast cancer model. RESULTS: All cell lines showed a significant growth inhibition with synergism in the sorafenib/AZ628 and selumetinib combination. Combination treatment resulted in higher Erk1/2 inhibition and in increased induction of apoptosis when compared to single agent treatments. However, single selumetinib treatment could cause adverse therapeutic effects, like increased cell migration in certain cells, selumetinib and sorafenib combination treatment lowered migratory capacity in all the cell lines. Importantly, combination resulted in significantly increased tumor growth inhibition in orthotropic xenografts of MDAMB231 cells when compared to sorafenib - but not to selumetinib - treatment. CONCLUSIONS: Our data suggests that combined blocking of RAF and MEK may achieve increased therapeutic response in non-V600 BRAF mutant tumors

    Live-Cell Microscopy Reveals Small Molecule Inhibitor Effects on MAPK Pathway Dynamics

    Get PDF
    Oncogenic mutations in the mitogen activated protein kinase (MAPK) pathway are prevalent in human tumors, making this pathway a target of drug development efforts. Recently, ATP-competitive Raf inhibitors were shown to cause MAPK pathway activation via Raf kinase priming in wild-type BRaf cells and tumors, highlighting the need for a thorough understanding of signaling in the context of small molecule kinase inhibitors. Here, we present critical improvements in cell-line engineering and image analysis coupled with automated image acquisition that allow for the simultaneous identification of cellular localization of multiple MAPK pathway components (KRas, CRaf, Mek1 and Erk2). We use these assays in a systematic study of the effect of small molecule inhibitors across the MAPK cascade either as single agents or in combination. Both Raf inhibitor priming as well as the release from negative feedback induced by Mek and Erk inhibitors cause translocation of CRaf to the plasma membrane via mechanisms that are additive in pathway activation. Analysis of Erk activation and sub-cellular localization upon inhibitor treatments reveals differential inhibition and activation with the Raf inhibitors AZD628 and GDC0879 respectively. Since both single agent and combination studies of Raf and Mek inhibitors are currently in the clinic, our assays provide valuable insight into their effects on MAPK signaling in live cells
    corecore