Desplazamiento activo en adolescentes: importancia de las barreras percibidas y el acompañamiento / Active Commuting in Adolescents: Importance of Perceived Barriers and Accompaniment

El presente estudio tiene como objetivo conocer el valor predictivo de la edad, el acompañamiento, y las barreras físicas y psicosociales en el desplazamiento activo. Participaron un total de 1325 estudiantes procedentes de centros educativos de Educación Primaria y Educación Secundaria de la Comunidad Autónoma de Extremadura (España), con edades comprendidas entre los 10-17 años ( =12.1; DT= 1.60). Los estudiantes cumplimentaron información sobre el modo, distancia, tiempo y acompañamiento a través del cuestionario PACO, y de las barreras percibidas para el desplazamiento activo mediante la escala BATACE. Los resultados revelaron una importante incidencia del acompañamiento, la distancia y las barreras psicosociales percibidas para la realización de desplazamiento activo hacia el colegio (R2 = .53; p = 0.00). Se concluye en la importancia de la distancia hasta el centro educativo, las barreras psicosociales, y el acompañamiento como elementos más importantes en la realización de desplazamiento activo. (AU)

The present study aims to know the predictive value of age, accompaniment, and physical and psychosocial barriers in active commuting. A total of 1,325 students from Primary Education and Secondary Education centers of the Autonomous Community of Extremadura (Spain) participated, with ages between 10-17 years (M =12.1; SD = 1.60). The students filled in information on the mode, distance, time and accompaniment through the PACO questionnaire, and the perceived barriers to active displacement using the BATACE scale. The results showed a significant incidence of accompaniment, distance, and perceived psychosocial barriers for active travel to school (R2 = .53; p = 0.00). It concludes on the importance of distance to the educational center, psychosocial barriers, and accompaniment as the most important elements in the realization of active displacement. (AU)

Motivación y barreras del desplazamiento activo en los profesores: Un estudio exploratorio / Motivation and Barriers to Active Commuting in Teachers: An Exploratory Study

El presente trabajo tuvo por objetivo conocer la relación entre la motivación intrínseca y motivación extrínseca con las barreras al desplazamiento activo en docentes. Se reclutaron un total de 156 profesores de 25 y 56 años (37.98 ± 12.28). Se utilizó una adaptación del cuestionario BREQ-3 para medir la motivación hacia el desplazamiento activo. Las barreras percibas se midieron con la escala BATACE. Se realizaron análisis descriptivos, correlaciones y modelos de regresiones de las variables de estudio. Los resultados mostraron que la motivación intrínseca estaba asociada negativamente con las barreras de planificación y psicosociales hacia el desplazamiento activo. La motivación extrínseca se asoció positivamente con las barreras ambientales y seguridad y con las barreras de planificación y psicosociales. Las intervenciones futuras, cuyo objetivo sea aumentar la cantidad de desplazamientos al centro educativo del profesorado, deberían aumentar la motivación intrínseca para conseguir resultados positivos en este comportamiento entre los docentes. (AU)

The aim of this study was to know the relationship between intrinsic and extrinsic motivation with the barriers associated with active commuting among Spanish teachers. The sample was formed by 156 teachers, ranging in age from 25 to 56 years old (37.98 ± 12.28). An adaptation of BREQ-3 questionnaire was used to measure the motivation towards active commuting. The perceived barriers were measured with the BATACE scale. Descriptive analysis, correlations and regression models of the studied variables were conducted. Results proved that the intrinsic variable was negatively associated with the planning and psychosocial barriers towards active commuting. Extrinsic motivation was positively related with the environmental and security barriers, as well as with planning and psychosocial barriers. Thus, future interventions aimed at increasing the number of teachers´ active travels to their schools should improve intrinsic motivation in order to achieve positive behavioral outcomes. (AU)

Study of the heavily p-type doping of cubic GaN with Mg.

We have studied the Mg doping of cubic GaN grown by plasma-assisted Molecular Beam Epitaxy (PA-MBE) over GaAs (001) substrates. In particular, we concentrated on conditions to obtain heavy p-type doping to achieve low resistance films which can be used in bipolar devices. We simulated the Mg-doped GaN transport properties by density functional theory (DFT) to compare with the experimental data. Mg-doped GaN cubic epitaxial layers grown under optimized conditions show a free hole carrier concentration with a maximum value of 6 × 1019 cm-3 and mobility of 3 cm2/Vs. Deep level transient spectroscopy shows the presence of a trap with an activation energy of 114 meV presumably associated with nitrogen vacancies, which could be the cause for the observed self-compensation behavior in heavily Mg-doped GaN involving Mg-VN complexes. Furthermore, valence band analysis by X-ray photoelectron spectroscopy and photoluminescence spectroscopy revealed an Mg ionization energy of about 100 meV, which agrees quite well with the value of 99.6 meV obtained by DFT. Our results show that the cubic phase is a suitable alternative to generate a high free hole carrier concentration for GaN.

Autologous tunica vaginalis graft to repair perineal hernia in shelter dogs.

In an effort to reduce shelter intake, Miami-Dade Animal Services (MDAS) Pet Retention Program offers caretakers with an opportunity to have animals treated for certain medical conditions, free of charge. Discovery of new, simple surgical techniques for low-cost procedures provides veterinarians with more surgical solutions, expands the capacity for services provided through low-cost veterinary clinics and other shelter programs, and provides shelters with life-saving alternatives that will increase adoptability of homeless pets and reduce euthanasia rates. The aim of this clinical trial was to describe and to evaluate the use of the autologous tunica vaginalis communis as a free graft to repair perineal hernia (PH) in intact male dogs at an animal shelter facility. In 2018, seven male intact dogs, diagnosed with perineal hernias (PH), were presented to MDAS. All dogs had the surgical reconstruction of the pelvic diaphragm repaired by using the tunica vaginalis communis obtained at the time of castration, prior to the perineal access, and sutured directly into the perineal defect. Clinical outcome including postoperative complications and hernia recurrence were obtained via telephone communication. The median follow-up time was 13 months. None of the dogs included in this study had recurrence of the PH. All dogs were adopted, were transferred to animal rescue organizations or were returned to their owners after the surgical procedure. The use of tunica vaginalis communis autograft is a simple, low-cost surgical technique that requires less surgical expertise and training and can be used for perineal herniorrhaphy in dogs, without long-term recurrence.

Shaping the zebrafish myotome by intertissue friction and active stress.

Organ formation is an inherently biophysical process, requiring large-scale tissue deformations. Yet, understanding how complex organ shape emerges during development remains a major challenge. During zebrafish embryogenesis, large muscle segments, called myotomes, acquire a characteristic chevron morphology, which is believed to aid swimming. Myotome shape can be altered by perturbing muscle cell differentiation or the interaction between myotomes and surrounding tissues during morphogenesis. To disentangle the mechanisms contributing to shape formation of the myotome, we combine single-cell resolution live imaging with quantitative image analysis and theoretical modeling. We find that, soon after segmentation from the presomitic mesoderm, the future myotome spreads across the underlying tissues. The mechanical coupling between the future myotome and the surrounding tissues appears to spatially vary, effectively resulting in spatially heterogeneous friction. Using a vertex model combined with experimental validation, we show that the interplay of tissue spreading and friction is sufficient to drive the initial phase of chevron shape formation. However, local anisotropic stresses, generated during muscle cell differentiation, are necessary to reach the acute angle of the chevron in wild-type embryos. Finally, tissue plasticity is required for formation and maintenance of the chevron shape, which is mediated by orientated cellular rearrangements. Our work sheds light on how a spatiotemporal sequence of local cellular events can have a nonlocal and irreversible mechanical impact at the tissue scale, leading to robust organ shaping.

[The neural bases of loss aversion in economic contexts: a systematic review according to the PRISMA guidelines]. / Bases neurales de la aversion a las perdidas en contextos economicos: revision sistematica segun las directrices PRISMA.

INTRODUCTION: Kahneman and Tversky's prospect theory has become the main model for the study of decision-making. One of its cornerstones, the loss aversion bias (greater sensitivity to losses than to gains), has been demonstrated from the behavioural perspective. AIMS: To analyse the evidence from neuroeconomics and check whether it is consistent with the existence of a neural mechanism of loss aversion. PATIENTS AND METHODS: A systematic review was performed, following the PRISMA guidelines, of the empirical studies found in PubMed and ScienceDirect, a total of 18 studies being included altogether. RESULTS AND CONCLUSIONS: The results consistently point to the implication of two opposing neural systems in this bias: one appetitive, involving the striatum and the frontal regions, and one aversive, involving the amygdala and the insula, which interact with each other when it comes to making a decision about different monetary bets and display a higher sensitivity towards losses. Although their functioning is not yet clear, what does seem evident is that the consistent involvement of these structures lends support to prospect theory and the limited rationality approach.

TITLE: Bases neurales de la aversion a las perdidas en contextos economicos: revision sistematica segun las directrices PRISMA.Introduccion. La teoria prospectiva de Kahneman y Tversky se ha convertido en el modelo principal para el estudio de la toma de decisiones. Uno de sus pilares, el sesgo de aversion a las perdidas (mayor sensibilidad a las perdidas que a las ganancias), se ha evidenciado desde el punto de vista conductual. Objetivo. Analizar las evidencias aportadas desde la neuroeconomia y comprobar si son consistentes con la existencia de un mecanismo neural de aversion a las perdidas. Pacientes y metodos. Se ha llevado a cabo una revision sistematica siguiendo las directrices PRISMA de los estudios empiricos encontrados en PubMed y ScienceDirect, incluyendo un total de 18 estudios. Resultados y conclusiones. Los resultados señalan consistentemente la implicacion en este sesgo de dos sistemas neurales opuestos: uno apetitivo, que involucra al estriado y a las regiones frontales, y uno aversivo, que involucra a la amigdala y a la insula, que interactuan entre ellos a la hora de tomar una decision en diferentes apuestas monetarias y muestran una mayor sensibilidad hacia las perdidas. Si bien todavia no esta claro su funcionamiento, lo que si parece evidente es que la consistente implicacion de estas estructuras constituye un apoyo a la teoria prospectiva y al enfoque de racionalidad limitada.

Transcriptional and cellular effects of paracetamol in the oyster Crassostrea gigas.

Acetaminophen (paracetamol) (PAR) is one of the most popular non-steroidal anti-inflammatory drugs (NSAIDs) with analgesic and antipyretic properties consumed worldwide and often detected in the aquatic environment. Due to the fact that PAR induces oxidative stress in mammals, the aim of this study was to evaluate if similar effects were observed in oysters Crassostrea gigas, given their economic and ecological importance and worldwide distribution. Oysters were exposed for 1, 4 and 7 days to two different sublethal PAR concentrations (0, 1 and 100µgL-1). Cell viability, DNA damage in hemocytes and enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH) and glutathione S-transferases (GST) were evaluated in oyster gills. In addition, changes at transcriptional level of Cu/Zn superoxide dismutase (SOD), catalase-like (CAT-like), cytochrome P450 genes (CYP30C1, CYP2AU2, CYP3071A1, CYP356A1), glutathione S-transferase isoforms (GST-ω and GST-π-like), cyclooxygenase (COX), fatty acid binding proteins-like (FABP-like), and caspase genes were evaluated in oyster gills and digestive gland. No changes in cell viability and DNA damage were observed in oysters exposed to both PAR concentrations. Similarly, no significant changes were detected in the major antioxidant enzymes (except for auxiliary enzyme GR) in oyster gills, suggesting that changes in GR activity are enough to counteract a potential oxidative stress in C. gigas gills under these experimental conditions. Furthermore, changes at transcriptional level are concentration and tissue dependent. PAR elicited an inhibition of CYP30C1, CYP3071A1 and FABP-like transcripts highlighting their role in drug metabolism, transport and detoxification of PAR in the gills. GST transcript levels were type, tissue and concentration-dependent. GST-π-like was down-regulated in oyster gills exposed to the lowest PAR concentration and up-regulated in the digestive gland of oysters exposed to the highest PAR concentration. However, GST-ω transcript levels were lower only in oysters digestive gland exposed to the lowest PAR concentration. Therefore, changes at transcriptional level were more sensitive to assess the exposure to PAR at environmental relevant concentrations.

[Arterial hypertension during pregnancy: Always preeclampsia?] / Hipertensión arterial durante el embarazo: ¿siempre preeclampsia?

Cushing's syndrome is a rare condition during pregnancy, but it is associated with serious maternal and fetal complications. The most common etiology during pregnancy is the presence of an adrenocortical adenoma. Urinary free cortisol over 3 times the upper limit of normal usually indicates Cushing's syndrome during pregnancy. The treatment of choice is surgical, and the ideal time for surgery is before the third trimester.

Phage-protease-peptide: a novel trifecta enabling multiplex detection of viable bacterial pathogens.

Bacteriophages represent rapid, readily targeted, and easily produced molecular probes for the detection of bacterial pathogens. Molecular biology techniques have allowed researchers to make significant advances in the bioengineering of bacteriophage to further improve speed and sensitivity of detection. Despite their host specificity, bacteriophages have not been meaningfully leveraged in multiplex detection of bacterial pathogens. We propose a proof-of-principal phage-based scheme to enable multiplex detection. Our scheme involves bioengineering bacteriophage to carry a gene for a specific protease, which is expressed during infection of the target cell. Upon lysis, the protease is released to cleave a reporter peptide, and the signal detected. Here we demonstrate the successful (i) modification of T7 bacteriophage to carry tobacco etch virus (TEV) protease; (ii) expression of TEV protease by Escherichia coli following infection by our modified T7, an average of 2000 units of protease per phage are produced during infection; and (iii) proof-of-principle detection of E. coli in 3 h after a primary enrichment via TEV protease activity using a fluorescent peptide and using a designed target peptide for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF MS) analysis. This proof-of-principle can be translated to other phage-protease-peptide combinations to enable multiplex bacterial detection and readily adopted on multiple platforms, like MALDI-TOF MS or fluorescent readers, commonly found in labs.

Effect of the relative optical air mass and the clearness index on solar erythemal UV irradiance.

This paper analyses the effects of the clearness index (Kt) and the relative optical air mass (mr) on erythemal UV irradiance (UVER). The UVER measurements were made in Valencia (Spain) from 6:00 am to 6:00 pm between June 2003 and December 2012 and (140,000 data points). Firstly, two models were used to calculate values for the erythemal ultraviolet irradiance clearness index (KtUVER) as a function of the global irradiance clearness index (Kt). Secondly, a potential regression model to measure the KtUVER as a function of the relative optical air mass was studied. The coefficients of this regression were evaluated for clear and cloudy days, as well as for days with high and low ozone levels. Thirdly, an analysis was made of the relationship between the two effects in the experimental database, with it being found that the highest degree of agreement, or the joint highest frequencies, are located in the optical mass range mr∈[1.0, 1.2] and the clearness index range of Kt∈[0.8, 1.0]. This is useful for establishing the ranges of parameters where models are more efficient. Simple equations have been tested that can provide additional information for the engineering projects concerning thermal installations. Fourthly, a high dispersion of radiation data was observed for intermediate values of the clearness for UV and UVER.

An empirical model of erythemal ultraviolet radiation in the city of Valencia, Spain.

This paper presents an improved empirical model that predicts ultraviolet erythemal radiation (UVER) and considers all aspects of atmospheric conditions in Valencia, Spain. The analyzed model is a potential function whose dependent variable is UVER radiation and independent variables are the clearness index and slant ozone column. A potential regression function with all the information contributed a small coefficient of determination and one chose to use a regression potential-exponential mathematical form which improved the coefficient of similar determination. A study was carried out on the influence of season on the regression parameters. This was found to be considerable due to the clearness index. The convergence between the values calculated by the model and the experimental values was analyzed using the mean bias error (MBE) and mean absolute bias error (MABE) statistical parameters. The clearness index and ozone column intervals were analyzed and found to give an improved prediction of the UVER clearness index using regression analysis. Also, a sensitivity analysis was performed on the regression coefficients and parameters. It is important to study the effects of UVER radiation predicted by the model on human health or on agriculture crop growth and yield.

DNA-PK, ATM and ATR collaboratively regulate p53-RPA interaction to facilitate homologous recombination DNA repair.

Homologous recombination (HR) and nonhomologous end joining (NHEJ) are two distinct DNA double-stranded break (DSB) repair pathways. Here, we report that DNA-dependent protein kinase (DNA-PK), the core component of NHEJ, partnering with DNA-damage checkpoint kinases ataxia telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR), regulates HR repair of DSBs. The regulation was accomplished through modulation of the p53 and replication protein A (RPA) interaction. We show that upon DNA damage, p53 and RPA were freed from a p53-RPA complex by simultaneous phosphorylations of RPA at the N-terminus of RPA32 subunit by DNA-PK and of p53 at Ser37 and Ser46 in a Chk1/Chk2-independent manner by ATR and ATM, respectively. Neither the phosphorylation of RPA nor of p53 alone could dissociate p53 and RPA. Furthermore, disruption of the release significantly compromised HR repair of DSBs. Our results reveal a mechanism for the crosstalk between HR repair and NHEJ through the co-regulation of p53-RPA interaction by DNA-PK, ATM and ATR.

Up-regulation of FXR isoforms is not required for stimulation of the expression of genes involved in the lack of response of colon cancer to chemotherapy.

Several mechanisms are involved in the poor response of colorectal adenocarcinoma (CRAC) to pharmacological treatment. Since preliminary evidences have suggested that the enhanced expression of farnesoid X receptor (FXR) results in the stimulation of chemoresistance, we investigated whether FXR up-regulation is required for the expression of genes that characterize the multidrug resistance (MDR) phenotype of CRAC. Samples of tumours and adjacent healthy tissues were collected from naive patients. Using Taqman Low-Density Arrays, the abundance of mRNA of 87 genes involved in MDR was determined. Relevant changes were re-evaluated by conventional RT-QPCR. In healthy tissue the major FXR isoforms were FXRα2(+/-) (80%). In tumours this predominance persisted (91%) but was accompanied by a consistent reduction (3-fold) in total FXR mRNA. A lower FXR expression was confirmed by immunostaining, in spite of which there was a significant change in the expression of MDR genes. Pharmacological challenge was simulated "in vitro" using human CRAC cells (LS174T cells). Short-term (72h) treatment with cisplatin slightly increased the almost negligible expression of FXR in wild-type LS174T cells, whereas long-term (months) treatment induced a cisplatin-resistant phenotype (LS174T/R cells), which was accompanied by a 350-fold up-regulation of FXR, mainly FXRα1(+/-). However, the changed expression of MDR genes in LS174T/R cells was not markedly affected by incubation with the FXR antagonist Z-guggulsterone. In conclusion, although the enhanced expression of FXR may be involved in the stimulation of chemoresistance that occurs during pharmacological treatment, FXR up-regulation is not required for the presence of the MDR phenotype characteristic of CRAC.

No correlation between the expression of FXR and genes involved in multidrug resistance phenotype of primary liver tumors.

Farnesoid X receptor (FXR) has been recently reported to enhance chemoresistance through bile acid-independent mechanisms. Thus, FXR transfection plus activation with GW4064 resulted in reduced sensitivity to cisplatin-induced toxicity. This is interesting because primary tumors of the liver, an organ where FXR is expressed, exhibit marked refractoriness to pharmacological treatment. Here we have determined whether FXR is upregulated in hepatocellular carcinoma (HCC), cholangiocarcinoma (CGC) and hepatoblastoma (HPB) and whether this is related with the expression of genes involved in mechanisms of chemoresistance. Using RT-QPCR and Taqman low density arrays we have analyzed biopsies from healthy livers or surgically removed tumors from naive patients and cell lines derived from HCC (SK-HEP-1, Alexander and Huh7), CGC (TFK1) and HPB (HepG2), before and after exposure to cisplatin at IC50 for 72 h. In liver tumors FXR expression was not enhanced but significantly decreased (healthy liver > HCC > HPB ≈ CGC). Except for CGC, this was not accompanied by changes in the proportions of FXR isoforms. Changes in 36 genes involved in drug uptake/efflux and metabolism, expression/function of molecular targets, and survival/apoptosis balance were found. Changes affecting SLC22A1, CYP2A1 and BIRC5 were shared by HCC, CGC and HPB. Similarity in gene expression profiles between cell lines and parent tumors was found. Pharmacological challenge with cisplatin induced changes that increased this resemblance. This was not dependent upon FXR expression. Thus, although FXR may play a role in inducing chemoresistance under certain circumstances, its upregulation does not seem to be involved in the multidrug resistance phenotype characteristic of HCC, CGC and HPB.

Specific improvement measures to reduce complications and mortality after urgent surgery in complicated abdominal wall hernia.

PURPOSE: Morbidity and mortality are increased after urgent surgery for complicated abdominal wall hernia. We analysed prospectively early morbidity and mortality after implementing specific management measures in patients undergoing urgent hernia repair. METHODS: The study population included 244 patients with complicated abdominal wall hernia requiring surgical repair on an emergency basis over 1-year period. Patients were managed according to a protocol that included specific actions to be implemented in the pre-, intra- and postoperative periods. Outcomes of these patients were compared with those of 402 undergoing similar operations before development of the protocol. RESULTS: Patients in whom acute complication was the first hernia symptom had higher mortality (7.2% vs 2.5%; P = 0.07) and were consulted later than 24 h (49.4% vs 36%; P = 0.044). Patients consulting later than 24 h had higher mortality (8.1% vs 1.4%, P = 0.017). Femoral hernias exhibited specific characteristics and were associated with higher mortality (13% vs 1.6%; P = 0.001). Overall, both groups had similar mortality (4.5% vs 4.1%; P = 0.8); complications (38.8% vs 37.7%; P = 0.2), and bowel resection rates (12.2% vs 11.5%; P = 0.8). Excluding the group of femoral hernias, the measures achieved a lower rate of severe complications (21.2% vs 10.3%; P = 0.04) and a decrease in mortality (2.9% vs 0.6%; P = 0.05) after bowel resection. CONCLUSIONS: Specific measures for improvement of management and prevention of complications and mortality were effective in patients without femoral hernia. To reduce mortality, the best applicable measure is early detection and to prioritize the scheduled operation of femoral hernias and those affecting high risk patients. The implementation of preventive and educational programs in high risk patients is essential.

[Ectopic relapse of an operated craniopharyngioma. Case report and review of the literature]. / Recidiva a distancia de craneofaringioma intervenido. Caso clínico y revisión de laliteratura.

INTRODUCTION. Craniopharyngioma is an embrionary tumor of the sellar and/suprasellar region derived from fusiform cells of Rathke´s cleft. Although locoregional relapse is the way classically proposed for relapse after treatment, it has been described, in a few cases, the possibility of ectopic relapse out of the sellar-suprasellar region, by direct seeding of cells during surgery on the surgical field, or by cell dissemination in the cerebrospinal fluid (CSF). It is proposed to report the case of a patient with relapse of a craniopharyngioma in the frontal lobe, who was previously operated ten years after, as well as to review the similar cases reported in the literature to the date. RESULTS. A systematic review of the literature has allowed to find 21 cases previously reported. Direct cellular seeding was the most frequent implantation mechanism. In all cases, the preferred treatment was radical surgical removal when this was possible. The time of latency between first surgery and relapse differed from 1 to 21 years. CONCLUSIONS. It is interesting, in the differential diagnosis, to bear in mind the possibility of ectopic relapse of craniopharyngioma in patients who have been operated because of this type of tumor and who present a new mass in nervous central system (CNS). In view of the long time of latency that can pass between the resection of a craniopharyngioma and his relapse, there becomes necessary a long follow-up of these patients by periodic imaging tests.

Derivation of cat embryonic stem-like cells from in vitro-produced blastocysts on homologous and heterologous feeder cells.

The domestic cat is a focal mammalian species that is used as a model for developing assisted reproductive technologies for preserving endangered cats and for studying human diseases. The generation of stable characterized cat embryonic stem cells (ESC) lines to use as donor nuclei may help to improve the efficiency of interspecies somatic cell nuclear transfer for preserving endangered cats and allow the creation of knockout cell lines to generate knockout cats for studying function of specific genes related to human diseases. It will also enable the possibility of producing gametes in vitro from ESC of endangered cats. In the present study, we report the generation of cat embryonic stem-like (cESL) cells from blastocysts derived entirely in vitro. We generated 32 cESL cell lines from 331 in vitro derived blastocysts from which inner cell masses were isolated by immunosurgery or by a mechanical method. Inhibition of cat dermal fibroblast (CDF) proliferation after exposure to mitomycin-C was both dose and time dependent, where doses of 30 to 40 microg/mL for 5 h were most efficient. These dosages were higher than that required to inhibit cell proliferation of mouse fetal fibroblasts (MFF; 10 microg/mL for 2.5 h). Mitomycin-C did not significantly increase necrosis of cells from either species, and had an anti-proliferative effect at concentrations below cytotoxicity. A clear species-specific relationship between feeder layers and derivation of cESL cell lines was observed, where higher numbers of cESL cell lines were generated on homologous cat feeder layers (n = 26) than from those derived on heterologous mouse feeder layers (n = 6). Three cESL cell lines generated from immunosurgery and cultured on CDF maintained self-renewal and were morphologically undifferentiated for nine and twelve passages (69-102 days). These lines showed a tightly packed dome shaped morphology, exhibited alkaline phosphatase activity and immuno-expression of the pluripotent marker OCT-4 and surface marker SSEA-1. Primary colonies at P0 to P3 and cat blastocysts expressed transcription factors OCT-4, NANOG and SOX-2 and the proto-oncogene C-MYC. However, expression was at levels significantly lower than in vitro produced blastocysts. During culture, cESL colonies spontaneously differentiated into fibroblasts, cardiomyocytes, and embryoid bodies. Development of techniques to prevent differentiation of cESL cells will be essential for maintaining defined cell lines.

Cell adhesion glycoprotein vitronectin during Xenopus laevis embryogenesis.

Vitronectin (vn) is a cell-adhesive glycoprotein present in blood and extracellular matrix of all vertebrates. In the present study we reported the cDNA cloning of Xenopus laevisvitronectin and its spatial and temporal expression pattern during the embryonic development of this important model organism. The deduced amino acid sequence of Xenopus laevis vn showed 49%, 47% and 43% identity with human, chicken and zebrafish orthologs, respectively, whereas the comparison with Xenopus tropicalis vn presented 85% identity. The structural organization consisting of a somatomedin B domain and two hemopexin-like domains was similar to higher vertebrate vitronectins. The vn transcripts were detected from stage 28 onward. At tadpole stages, vn is expressed in heart, gut derivatives and in the notochord. The protein was detected in heart, liver, foregut, pronephros and notochord at stages 43 and 47 of Xenopus embryos. Our results suggest that vitronectin is developmentally regulated and could participate in embryo organogenesis.