Impact of sodium butyrate and mild hypothermia on metabolic and physiological behaviour of CHO TF 70R cells

Background: To reduce costs associated with productivity of recombinant proteins in the biopharmaceutical industry, research has been focused on regulatory principals of growth and survival during the production phases of the cell culture. The main strategies involve the regulation of cell proliferation by the modulation of cell cycle control points (G1/S or G2/M) with mild hypothermia and the addition of sodium butyrate (NaBu). In this study, batch culture strategies were evaluated using CHO TF 70R cells producing the recombinant human tissue plasminogen activator (rh-tPA), to observe their individual and combined effect on the cellular physiological state and relevant kinetic parameters. Results: NaBu addition has a negative effect on the mitochondrial membrane potential (ΔΨm), the values of which are remarkably diminished in cultures exposed to this cytotoxic compound. This effect was not reflected in a loss of cell viability. NaBu and mild hypothermic conditions increased the doubling time in the cell cultures, suggesting that these strategies triggered a general slowing of each cell cycle phase in a different way. Finally, the individual and combined effect of NaBu and mild hypothermia produced an increase in the specific rh-tPA productivity in comparison to the control at 37°C without NaBu. Nevertheless, both strategies did not have a synergistic effect on the specific productivity. Conclusions: The combination of NaBu addition and mild hypothermic condition causes an impact on physiological and metabolic state of CHO TF 70R cells, decreasing cell growth rate and improving glucose consumption efficiency. These results therefore provide a promising strategy to increase specific productivity of rh-tPA.

Entrepreneurship perception in higher education. A comparative study among Students, Faculty Members and Directors / Percepción del Emprendimiento en Educación Superior. Estudio comparativo entre Estudiantes, Equipos Académico y Personal Directivo / Percepção do empreendedorismo no ensino superior. Estudo comparativo entre estudantes, académicos e diretores

A set of variables affects the building of a university ecosystem fostering an entrepreneurial culture among students. The purpose of this study was to assess the perceptions of students, faculty members and directors of Higher Education Centers in the region of Coquimbo, Chile with respect to entrepreneurship, taking into account diverse variables in order to establish significant differences in these perceptions that could affect institutional policies or actions, which may ultimately have an impact in regional development. The descriptive study performed on a sample of twelve Higher Education institutions revealed significant differences between the perceptions of academics and students on the influence of the following variables: infrastructure; networking; institutional experience; skills; risk-taking. Likewise, the directors showed significant differences in their appreciations of the relative importance of the variables: teaching strategies; academic skills; government programs and strategies covering students and/or academics.

La construcción de un ecosistema universitario que genere una cultura emprendedora en sus futuros profesionales, se ve influenciada por una serie de variables que fomentan su desarrollo. Nuestro objetivo en este estudio es evaluar las percepciones que tienen los sujetos estudiantes, los equipos académico y el personal directivo de los Centros de Educación Superior en la región de Coquimbo, Chile, respecto al emprendimiento, considerando diversas variables a fin de poder establecer la existencia de diferencias significativas en dichas percepciones, que pueden incidir en las políticas de estas instituciones o en las acciones al interior de ellas, las que finalmente impactan en el desarrollo regional. El estudio descriptivo que realizamos sobre una muestra de doce centros de educación superior, permite concluir que existen diferencias significativas en la percepción entre sujetos académicos y estudiantes en las variables que influyen; estas son: infraestructura, networking, experiencia institucional, competencias del sujeto estudiante y capacidad frente al riesgo. Así mismo, los directores y directoras presentan diferencias significativas en las variables estrategias de enseñanza, competencias de académicos y programas y estrategias de gobierno tanto con estudiantes como con personal académico.

A construção de um ecossistema universitário que promova uma cultura empreendedora em seus futuros profissionais se vê influenciada por uma série de variáveis que fomentam o seu desenvolvimento. O objetivo deste estudo é avaliar as percepções dos estudantes, dos acadêmicos e dos diretores dos centros de educação superior na região de Coquimbo, Chile, a respeito do empreendedorismo, considerando diversas variáveis, a fim de estabelecer a existência de diferenças significativas nessas percepções, que podem afetar as políticas dessas instituições ou as ações dentro deles, o que acaba impactando no desenvolvimento regional. O estudo descritivo realizado sobre uma amostra de doze instituições de ensino superior permite concluir que existem diferenças significativas na percepção entre acadêmicos e estudantes em relação às variáveis as quais influenciam, essas são: infraestrutura, networking, experiência institucional, competências do estudante e capacidade frente ao risco. Da mesma forma, os diretores apresentam diferenças significativas nas variáveis estratégias de ensino, competências acadêmicas e de programas e estratégias governamentais tanto para estudantes como para acadêmicos.

Antiproliferative evaluation of tall-oil docosanol and tetracosanol over CHO-K1 and human melanoma cells

Background Polycosanols derived from plant species have traditionally been used in medicine as antiproliferative agents for treating various viruses (primarily the herpes simplex virus). However, few studies have studied their effects on hyperproliferative cell lines. In this work, the antiproliferative capacity of polycosanols from tall-oil pitch, obtained from black liquor soaps in the kraft pulping process of cellulose (specifically from Pinus radiata, Pinus taede, and Eucalyptus globulus), was evaluated on CHO-K1 and CRL-1974 human melanoma cell lines. Results The proliferative capacities and cell viabilities were measured for 72 and 140 h, respectively. Treatment with docosanol produced differential effects on the CHO-K1 and human melanoma cells and significantly affected their proliferation rates, but not their cell viabilities. Tetracosanol produced a significant negative effect on the proliferation of human melanoma cells, and this effect was less than that caused by docosanol. However, it had no effect on the proliferation of CHO-K1 cells and did not induce any significant effect on the viability of the studied cell lines. Conclusion Docosanol and tetracosanol induced antiproliferative effects on the studied cell lines and exhibited significantly greater effects on the oncogenic cell lines. Prior to this study, the capacity of these polycosanols has never been investigated. Future studies will be necessary to determine their mechanisms of action on these cell systems.

Advances in improving mammalian cells metabolism for recombinant protein production

Background: The production of recombinant proteins for therapeutic use represents a great impact on the biotechnology industry. In this context, established mammalian cell lines, especially CHO cells, have become a standard system for the production of such proteins. Their ability to properly configure and excrete proteins in functional form is an enormous advantage which should be contrasted with their inherent technological limitations. These cell systems exhibit a metabolic behaviour associated with elevated cell proliferation which involves a high consumption of glucose and glutamine, resulting in the rapid depletion of these nutrients in the medium and the accumulation of ammonium and lactate. Both phenomena contribute to the limitation of cell growth, the triggering of apoptotic processes and the loss of quality of the recombinant protein. Results: In this review, the use of alternative substrates and genetic modifications (host cell engineering) are analyzed as tools to overcome those limitations. In general, the results obtained are promising. However, metabolic and physiological phenomena involved in CHO cells are still barely understood. Thus, most of publications are focused on specific modifications rather than giving a systemic perspective. Conclusions: A deeper insight in the integrated understanding of metabolism and cell mechanisms is required in order to define complementary strategies at these two levels, so providing effective means to control nutrients consumption, reduce by-products and increase process productivity.

Simultaneous environmental manipulations in semi-perfusion cultures of CHO cells producing rh-tPA

We evaluated the combined effect of decreasing the temperature to a mild hypothermia range (34 and 31ºC) and switching to a slowly metabolizable carbon source (glucose substituted by galactose) on the growth and production of a recombinant human tissue plasminogen activator (rh-tPA) by Chinese hamster ovary cells in batch and semi-perfusion cultures. In batch cultures using glucose as a carbon source, decreasing the temperature caused a reduction in cell growth and an increase in specific productivity of rh-tPA of 32 percent at 34ºC and 55 percent at 31ºC, compared to cultures at 37ºC. Similar behaviour was observed in cultures at 34ºC using galactose as a carbon source. Nonetheless, at 31ºC, the specific productivity of rh-tPA strongly decreased (about 58 percent) compared to the culture at 37ºC. In semi-perfusion culture, the highest rh-tPA specific productivity was obtained at 34ºC. Similarly, whether a decrease in the temperature is accompanied of the replacement of glucose by galactose, the rh-tPA specific productivity improved about 112 percent over that obtained in semi-perfusion culture carried out at 37ºC with glucose as the carbon source. A semi-perfusion culture strategy was implemented based on the combined effect of the chosen carbon source and low temperatures, which was a useful approach for enhance the specific productivity of the recombinant protein.

Uso de Perican más Sutura de mono filamento como pasador de sutura en reparaciones artroscópicas del manguito rotador / Using more Perican monofilament suture and suture passer in arthroscopic rotator cuff repairs

Las lesiones del tendón del manguito rotador son comunes, de no ser reparadas llevan a dolor persistente e incapacidad. En este reporte describimos una técnica quirúrgica usando un PERICAN® más un monofilamento como pasador de sutura. Esta técnica permite la reparación del tendón de forma fácil, no requiere portales y a un bajo costo.

Programa de screening y tratamiento de cáncer de mama / Screening and treatment program of breast cancer

En enero de 1988 comenzamos un programa piloto de screening en cáncer de mama para mujeres asintomáticas. Una mamografía con dos proyecciones se planificó cada 2 años para las mujeres entre 40 y 50 años y anualmente para aquéllas con 50 años o más. Si en esta mamografía se encontraban hallazgos anormales, las mujeres fueron evaluadas con estudios localizados y examen físico realizado por un comité constituído por un radiólogo, un cirujano y un oncólogo. Si luego de esta evaluación la anormalidad del estudio persiste, a juicio del comité, la paciente se planifica para biopsia excisional. Si el resultado de la biopsia es positivo y la enfermedad es localizada, la paciente es tratada conservadoramente con radioterapia. Hasta el 31 de enero de 1990 en 1.742 mujeres se ha realizado este screening y 2.573 mamografías han sido tomadas (en 831 se ha realizado 2 exámenes), 42% de las mujeres tienen 50 años o menos. Después del primer examen 32 mujeres fueron seleccionados para biopsia (24 tenían una lesión no-palpable). Después de la biopsia 4 cánceres fueron diagnosticadas (sólo una palpable) y en otra mujer, una hiperplasia epitelial atípica con lesión no palpable. Después del segundo examen 20 mujeres fueron a biopsia (12 con lesiones no palpables) y 5 cánceres se diagnosticaron (tres no-palpables). De estos 5 cánceres, 2 podrían haber sido vistos en el examen previo, ambos no palpables y tres eran nuevas lesiones. El screening de cáncer de mama es posible de realizar, detecta lesiones pequeñas, permitiendo un tratamiento conservador de las mismas y mejora la sobrevida del cáncer de mama