Dynamic stem cell heterogeneity.

Recent lineage-tracing studies based on inducible genetic labelling have emphasized a crucial role for stochasticity in the maintenance and regeneration of cycling adult tissues. These studies have revealed that stem cells are frequently lost through differentiation and that this is compensated for by the duplication of neighbours, leading to the consolidation of clonal diversity. Through the combination of long-term lineage-tracing assays with short-term in vivo live imaging, the cellular basis of this stochastic stem cell loss and replacement has begun to be resolved. With a focus on mammalian spermatogenesis, intestinal maintenance and the hair cycle, we review the role of dynamic heterogeneity in the regulation of adult stem cell populations.B.D.S. acknowledges the financial support of the Wellcome Trust [098357/Z/12/Z] as well as core grants from the Wellcome Trust [092096] and Cancer Research UK [C6946/A14492].This is the author accepted manuscript. The final version is available via The Company of Biologists at http://dev.biologists.org/content/142/8/1396.abstract

Combined imaging and sequencing to model glioblastoma invasion

Glioblastoma (GBM) is the most frequent and most aggressive primary adult brain tumour, with an expected survival time of only 12-15 months from diagnosis and a 5-year survival rate of 5%. Despite intensive research, treatment outcomes for GBM have barely improved over the past decades. Invasion of tumour cells into the surrounding brain tissue and significant genetic and transcriptional heterogeneity have impeded therapeutic progress. In the work presented here, we harness recent advances in organoid generation and single-cell sequencing technologies to establish an experimental model system of glioblastoma invasion into brain organoids. We establish human brain organoids from induced pluripotent stem cells (iPSCs) and co-culture them with fluorescently labelled patient-derived GBM cells. Tumour cells invade into organoids within three days and extend membrane-bound microtubes that are up to 450 μm long, mirroring the formation of GBM cell networks previously observed in vivo. Invasion is visualised and quantified by tissue clearing and confocal microscopy. Our model is highly scalable and reproducible, enabling the study of the invasion process on clinically relevant timescales of less than one month in high-throughput applications. Single-cell transcriptomics analyses of GBM cells before and after co-culture with organoid cells reveal substantial interpatient heterogeneity, but also identify transcriptional changes that are consistent across patients and may thus be generally implicated in the interactions of tumour cells with normal brain cells. Novel treatment strategies targeting tumour invasion and microtube formation could therefore provide clinical benefit to GBM patients in the future. Together, these results demonstrate the utility of our experimental system for modelling glioblastoma invasion in vitro to improve our understanding of glioblastoma biology, as well as our ability to develop targeted therapies and select personalised treatment approaches for this as yet uncurable disease.Glioblastome (GBM) sind die häufigsten und aggressivsten primären Hirntumore bei Erwachsenen, mit einer Lebenserwartung von nur 12-15 Monaten ab der Diagnose und einer 5-Jahres-Überlebensrate von 5%. Trotz intensiver Forschung haben sich die Behandlungsergebnisse für GBM in den letzten Jahrzehnten kaum verbessert. Die Invasion von Tumorzellen in das umliegende Hirngewebe sowie die signifikante genetische und transkriptionelle Heterogenität erschweren Fortschritte in der Therapie. In der hier vorgestellten Arbeit nutzen wir neuere Entwicklungen in der Generierung von Organoiden und der Einzelzellsequenzierung, um die Invasion von GBM-Zellen in Hirnorganoide experimentell zu modellieren. Wir etablieren humane Hirnorganoide basierend auf induzierten pluripotenten Stammzellen und kultivieren sie gemeinsam mit fluoreszenzmarkierten GBM-Zellen. Tumorzellen migrieren innerhalb von drei Tagen in die Organoide hinein und entwickeln membranumhüllte, schlauchförmige Ausstülpungen, genannt ‚microtubes‘, die bis zu 450 μm lang werden. Sie spiegeln damit die Ausbildung von Netzwerken aus Glioblastomzellen wider, die bereits in vivo beobachtet wurde. Mittels Gewebereinigung und Konfokalmikroskopie visualisieren und quantifizieren wir die Tumorinvasion. Unser Modell ist hochgradig skalierbar und reproduzierbar und ermöglicht so die Untersuchung des Invasionsprozesses innerhalb klinisch relevanter Zeiträume von weniger als einem Monat in Hochdurchsatzverfahren. Einzelzell-Transkriptomanalysen von GBM-Zellen vor und nach Ko-Kultur mit Organoidzellen offenbaren erhebliche Heterogenität zwischen Patienten, identifizieren aber auch übereinstimmende transkriptionelle Veränderungen über alle Patienten hinweg, die generell zur Interaktion von Tumorzellen mit normalen Hirnzellen beitragen könnten. Neuartige Behandlungsstrategien, die auf die Tumorinvasion und die Bildung von ‚microtubes‘ abzielen, könnten daher zukünftig klinischen Nutzen für Patienten mit Glioblastomen bringen. Insgesamt demonstrieren unsere Ergebnisse die Anwendung unseres experimentellen Systems zur Modellierung der Invasion von Glioblastomen in vitro. Unser Modell kann dazu beitragen, unser Verständnis dieser bislang unheilbaren Erkrankung zu verbessern, zielgerichtete Therapien zu entwickeln und personalisierte Behandlungsstrategien zu ermitteln

Single-cell analysis of patient-derived PDAC organoids reveals cell state heterogeneity and a conserved developmental hierarchy

Pancreatic tumors are frequently divided into basal and classical subtypes. Here, the authors use single cell sequencing to investigate organoids derived from pancreatic cancer tissue and find a hierarchy of distinct cell states, and classical and basal cells existing within the same tumor. Pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer mortality by 2030. Bulk transcriptomic analyses have distinguished 'classical' from 'basal-like' tumors with more aggressive clinical behavior. We derive PDAC organoids from 18 primary tumors and two matched liver metastases, and show that 'classical' and 'basal-like' cells coexist in individual organoids. By single-cell transcriptome analysis of PDAC organoids and primary PDAC, we identify distinct tumor cell states shared across patients, including a cycling progenitor cell state and a differentiated secretory state. Cell states are connected by a differentiation hierarchy, with 'classical' cells concentrated at the endpoint. In an imaging-based drug screen, expression of 'classical' subtype genes correlates with better drug response. Our results thus uncover a functional hierarchy of PDAC cell states linked to transcriptional tumor subtypes, and support the use of PDAC organoids as a clinically relevant model for in vitro studies of tumor heterogeneity

ANÁLISIS ECONOMÉTRICO DE LAS VENTAS DE PULPA DE MANGO DE FROZEN PULPS DE MÉXICO SA DE CV

ResumenEn este trabajo se realizó un análisis económico de las ventas de pulpa de mango de Frozen Pulps de México SA de CV, con el propósito de establecer estadísticamente los factores que las determinan. Para lograr lo anterior se formuló un modelo econométrico sustentado en la teoría de la oferta, se conformaron series de tiempo para las variables involucradas con información anual de 2004 a 2014 y, la ecuación de regresión fue estimada vía mínimos cuadrados ordinarios (MCO). Los resultados indican que el precio propio de la producción de mango, el precio de exportación y el tipo de cambio son factores que inciden positiva e intensamente en las ventas de exportación de pulpa de mango de la empresa. El salario mínimo general es el factor que registró el valor de elasticidad económica más alto (en términos absolutos) sobre las ventas (-2.65), seguido por el tipo de cambio (1.96).Palabras clave: Exportación, modelo econométrico, pulpa de mango. AbstractThis paper presents an economic analysis of sales of Frozen Pulps de Mexico SA de CV, in order to establish statistically determining factors. To achieve this an econometric model based on the theory of supply was made, time series were formed for the variables involved with annual data from 2004 to 2014 and the regression equation was estimated with ordinary least squares minimun (OLS). The results indicate that the proper price of mango production, export price and exchange rate are factors that impact positively and intensely in export sales of company. The general minimum wage is the factor which recorded the highest economic value of elasticity (in absolute terms) on sales (-2.65), followed by the exchange rate (1.96).Keywords: Export, econometric model, mango pulp

Biodiesel production as a model of approach to natural sciences

Contextualizar los laboratorios de química, relacionándolos con situaciones de la vida diaria y contenidos disciplinares, motiva a despertar vocaciones científicas. El objetivo del trabajo fuefomentar el interés por las ciencias exactas y el cuidado medioambiental, a través de la participación activa de los estudiantes en la reutilización del aceite vegetal como modelo de laboratorio en contexto. Durante los talleres se estudió el origen de los aceites vegetales, las implicancias sobre la salud de la reiterada reutilización del aceite vegetal, las posibles formas de transformación en nuevos productos, la transesterificación, y la manipulación de reactivos químicos. Los destinatarios fueron estudiantes del nivel medio de 6 instituciones diferentes de laprovincia de Misiones (Argentina), ascendiendo a un total de 45 estudiantes de entre 17 a 21 años. Los talleres estuvieron a cargo de estudiantes, graduados y las directoras del proyecto. La metodología de la actividad consistió en una experiencia práctica y evaluación de la intervención. El empleo de un contexto socioambiental para la enseñanza de la química, generó concientización acerca de los cuidados del medioambiente; y nuevo conocimiento en relación con la química, al hacer uso de la reacción de transesterificación para la obtención de biodiesel.Contextualizing chemistry laboratories, relating them to daily life situations and disciplinary contents, motivates to awaken scientific vocations. The objective of the work was to promote interest in exact sciences and environmental care, through the active participation of students in the reuse of vegetable oil as a laboratory model in context. The origin of vegetable oils, the health implications of the repeated reuse of vegetable oil, the possible forms of transformation into new products, transesterification, and the manipulation of chemical reagents were studied during the workshops. Recipients were high school students from 6 different institutions in the province of Misiones (Argentina), reaching a total of 45 students between 17 and 21 years old. Workshops were led by students, graduates and the directors of the project. The methodology of the activity consisted of a practical experience and evaluation of the intervention. The use of a socioenvironmental context for the teaching of chemistry, generated awareness about environmental care; and new knowledge in relation to chemistry, by making use of the transesterification reaction to obtain biodiesel.Fil: Rodríguez, María Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Espinosa, Teresa Genara. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Gallará, Belén. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Oneto, María Eugenia. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Fernández Erbes, Loreley. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Krieger, Andrea Elizabeth. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Miguel, Nicolás. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Morel, Camila. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; ArgentinaFil: Zapata, Pedro Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Departamento de Bioquímica Clínica. Laboratorio de Biotecnología Molecular; Argentin

Hormone Replacement Therapy advertising: sense and nonsense on the web pages of the best-selling pharmaceuticals in Spain

Background. The balance of the benefits and risks of long term use of hormone replacement therapy (HRT) have been a matter of debate for decades. In Europe, HRT requires medical prescription and its advertising is only permitted when aimed at health professionals (direct to consumer advertising is allowed in some non European countries). The objective of this study is to analyse the appropriateness and quality of Internet advertising about HRT in Spain. Methods. A search was carried out on the Internet (January 2009) using the eight best-selling HRT drugs in Spain. The brand name of each drug was entered into Google's search engine. The web sites appearing on the first page of results and the corresponding companies were analysed using the European Code of Good Practice as the reference point. Results. Five corporate web pages: none of them included bibliographic references or measures to ensure that the advertising was only accessible by health professionals. Regarding non-corporate web pages (n = 27): 41% did not include the company name or address, 44% made no distinction between patient and health professional information, 7% contained bibliographic references, 26% provided unspecific information for the use of HRT for osteoporosis and 19% included menstrual cycle regulation or boosting feminity as an indication. Two online pharmacies sold HRT drugs which could be bought online in Spain, did not include the name or contact details of the registered company, nor did they stipulate the need for a medical prescription or differentiate between patient and health professional information. Conclusions. Even though pharmaceutical companies have committed themselves to compliance with codes of good practice, deficiencies were observed regarding the identification, information and promotion of HRT medications on their web pages. Unaffected by legislation, non-corporate web pages are an ideal place for indirect HRT advertising, but they often contain misleading information. HRT can be bought online from Spain, without a medical consultation or prescription constituting a serious issue for public health. In our information society, it is the right and obligation of public health bodies to ensure that such information is not misleading.This study is funded by the Women's Institute (Ref: 773; Expte.69/05)