"Re-huminization": the role of human-animal similarity in predicting prejudice towards immigrants and non-human animals

Research implies that there ~ay be an association between attitudes toward margil1alized human outgroups and non-human animals. Very few studies, however, have specifically tested this relation empirically. The general purpose of the present research was to determine if such a relation exists and if perceptions of human-animal similarity avail as a common predictor of both types of attitudes. Ideological orientations associated with prejudiced attitudes (Social Dominance Orientation, Right-Wing Authoritarianism, and Universal Orientation) were also examined as individual differences in predicting perceptions of human-animal similarity. As predicted, people who endorsed prejudiced attitudes toward human outgroups (Study 1) and immigrants in particular (Studies 2 and 3), were more likely to endorse prejudiced attitudes toward non-human animals. In Study 2, perceptions that humans are superior (versus similar) to other animals directly predicted higher levels of prejudice toward non-human animals, whereas the effect of human superiority beliefs on immigrant prejudice was mediated by dehumanization. In other words, greater perceptions of humans as superior (versus similar) to other animals "allowed for" greater dehumanization of immigrants, which in turn resulted in heightened immigrant prejudice. Furthermore, people higher in Social Dominance Orientation or Right-Wing Authoritarianism were particularly likely to perceive humans as superior (versus similar) to other animals, whereas people characterized by a greater Universal Orientation were more likely to perceive humans and non-human animals as similar. Study 3 examined whether inducing perceptions of human-animal similarity through experimental manipulation would lead to more favourable attitudes toward non-human animals and immigrants. Participants were randomly assigned to read one of four 11 editorials designed to highlight either the similarities or differences between humans and other animals (i.e., animals are similar to humans; humans are similar to animals;~~nimals are inferior to humans; humans are superior to animals) or to a neutral control condition. Encouragingly, when animals were described as similar to humans, prejudice towards non-human animals and immigrants was significantly lower, and to some extent this finding was also true for people naturally high in prejudice (i.e., high in Social Dominance Orientation or Right-Wing Authoritarianism). Inducing perceptions that nonhuman animals are similar to humans was particularly effective at reducing the tendency to dehumanize immigrants ("re-humanization"), lowering feelings of personal threat regarding one's animal-nature, and at increasing inclusive intergroup representations and empathy, all of which uniquely accounted for the significant decreases in prejudiced attitudes. Implications for research, theory and prejudice interventions are considered.

Crumpet structures: experimental and modelling studies

Crumpets are made by heating fermented batter on a hot plate at around 230°C. The characteristic structure dominated by vertical pores develops rapidly: structure has developed throughout around 75% of the product height within 30s, which is far faster than might be expected from transient heat conduction through the batter. Cooking is complete within around 3 min. Image analysis based on results from X-ray tomography shows that the voidage fraction is approximately constant and that there is continual coalescence between the larger pores throughout the product although there is also a steady level of small bubbles trapped within the solidified batter. We report here experimental studies which shed light on some of the mechanisms responsible for this structure, together with some models of key phenomena.Three aspects are discussed here: the role of gas (carbon dioxide and nitrogen) nuclei in initiating structure development; convective heat transfer inside the developing pores; and the kinetics of setting the batter into an elastic solid structure. It is shown conclusively that the small bubbles of carbon dioxide resulting from the fermentation stage play a crucial role as nuclei for pore development: without these nuclei, the result is not a porous structure, but rather a solid, elastic, inedible, gelatinized product. These nuclei are also responsible for the tiny bubbles which are set in the final product. The nuclei form the source of the dominant pore structure which is largely driven by the, initially explosive, release of water vapour from the batter together with the desorption of dissolved carbon dioxide. It is argued that the rapid evaporation, transport and condensation of steam within the growing pores provides an important mechanism, as in a heat pipe, for rapid heat transfer, and models for this process are developed and tested. The setting of the continuous batter phase is essential for final product quality: studies using differential scanning calorimetry and on the kinetics of change in the visco-elastic properties of the batter suggest that this process is driven by the kinetics of gelatinization. Unlike many thermally driven food processes the rates of heating are such that gelatinization kinetics cannot be neglected. The implications of these results for modelling and for the development of novel structures are discussed.

Development and experimental identification of a biomechanical model of the trunk for functional electrical stimulation control in paraplegia

Objectives. Theoretic modeling and experimental studies suggest that functional electrical stimulation (FES) can improve trunk balance in spinal cord injured subjects. This can have a positive impact on daily life, increasing the volume of bimanual workspace, improving sitting posture, and wheelchair propulsion. A closed loop controller for the stimulation is desirable, as it can potentially decrease muscle fatigue and offer better rejection to disturbances. This paper proposes a biomechanical model of the human trunk, and a procedure for its identification, to be used for the future development of FES controllers. The advantage over previous models resides in the simplicity of the solution proposed, which makes it possible to identify the model just before a stimulation session ( taking into account the variability of the muscle response to the FES). Materials and Methods. The structure of the model is based on previous research on FES and muscle physiology. Some details could not be inferred from previous studies, and were determined from experimental data. Experiments with a paraplegic volunteer were conducted in order to measure the moments exerted by the trunk-passive tissues and artificially stimulated muscles. Data for model identification and validation also were collected. Results. Using the proposed structure and identification procedure, the model could adequately reproduce the moments exerted during the experiments. The study reveals that the stimulated trunk extensors can exert maximal moment when the trunk is in the upright position. In contrast, previous studies show that able-bodied subjects can exert maximal trunk extension when flexed forward. Conclusions. The proposed model and identification procedure are a successful first step toward the development of a model-based controller for trunk FES. The model also gives information on the trunk in unique conditions, normally not observable in able-bodied subjects (ie, subject only to extensor muscles contraction).

the implication of social cognition for experimental economics From the issue entitled "Special issue on Experimental economics and the social embedding of economic behavior and cognition"

Can human social cognitive processes and social motives be grasped by the methods of experimental economics? Experimental studies of strategic cognition and social preferences contribute to our understanding of the social aspects of economic decisions making. Yet, papers in this issue argue that the social aspects of decision-making introduce several difficulties for interpreting the results of economic experiments. In particular, the laboratory is itself a social context, and in many respects a rather distinctive one, which raises questions of external validity.

Highly efficient neural differentiation of human somatic stem cells, isolated by minimally invasive periodontal surgery

Neural stem cells (NSCs) are potential sources for cell therapy of neurodegenerative diseases and for drug screening. Despite their potential benefits, ethical and practical considerations limit the application of NSCs derived from human embryonic stem cells (ES) or adult brain tissue. Thus, alternative sources are required to satisfy the criteria of ready accessibility, rapid expansion in chemically defined media and reliable induction to a neuronal fate. We isolated somatic stem cells from the human periodontium that were collected during minimally invasive periodontal access flap surgery as part of guided tissue regeneration therapy. These cells could be propagated as neurospheres in serum-free medium, which underscores their cranial neural crest cell origin. Culture in the presence of epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2) under serum-free conditions resulted in large numbers of nestin-positive/Sox-2-positive NSCs. These periodontium-derived (pd) NSCs are highly proliferative and migrate in response to chemokines that have been described as inducing NSC migration. We used immunocytochemical techniques and RT-PCR analysis to assess neural differentiation after treatment of the expanded cells with a novel induction medium. Adherence to substrate, growth factor deprivation, and retinoic acid treatment led to the acquisition of neuronal morphology and stable expression of markers of neuronal differentiation by more than 90% of the cells. Thus, our novel method might provide nearly limitless numbers of neuronal precursors from a readily accessible autologous adult human source, which could be used as a platform for further experimental studies and has potential therapeutic implications.

In utero and lactational exposure to fenvalerate disrupts reproductive function in female rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Re-examination of the anion derivatives of isoflavones by radical fragmentation in negative electrospray ionization tandem mass spectrometry: experimental and computational studies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise do imprinting e da expressão dos genes H19 e IGF2 em células de Sertoli humanas apos exposição in vitro ao 2,3,7,8-Tetraclorodibenzo-p-dioxina (TCDD)

Pós-graduação em Biologia Geral e Aplicada - IBB

Um análogo experimental de uma prática cultural: efeitos de um produto agregado contingente, mas não contíguo, sobre uma contigência de reforçamento entrelaçada

De acordo com o modo causal de seleção por consequências proposto por Skinner, o comportamento humano é o produto de processos seletivos em três níveis: filogênese, ontogênese e cultura. Investigações empíricas que se ocupem do terceiro nível apenas começam a ser realizadas na análise do comportamento. No campo teórico, Glenn introduziu o conceito de Metacontingência para enfocar relações funcionais entre contingências de reforçamento entrelaçadas e um produto agregado que seleciona o próprio entrelaçamento. Um trabalho pioneiro na reprodução em laboratório de uma metacontingência foi produzido por Vichi, a partir da adaptação de um método usado em estudos experimentais na sociologia. O estudo de Vichi sugere que o entrelaçamento dos comportamentos das pessoas de um pequeno grupo pôde ser modificado por produtos agregados que estes entrelaçamentos produziam, caracterizando uma Metacontingência. O presente trabalho consistiu de uma replicação do estudo de Vichi, com o objetivo de verificar se contingências comportamentais entrelaçadas podem de fato ser selecionadas e mantidas por um produto agregado contingente aos comportamentos dos membros de um pequeno grupo em uma microcultura de laboratório. Participaram da pesquisa oito alunos universitários, divididos em dois grupos de quatro, que realizaram uma tarefa em grupo. A tarefa consistiu em resolver um problema, escolhendo uma linha de uma matriz de 8 colunas por 8 fileiras, com sinais positivos e negativos. Os participantes escolhiam as linhas e o experimentador escolhia as colunas. Um sinal positivo na interseção das duas escolhas resultava em ganho para o grupo; um sinal negativo, em perda. A escolha da coluna pelo experimentador não foi aleatória, mas contingente ao modo de distribuição (igualitária ou desigual) dos ganhos pelo grupo na tentativa imediatamente anterior. Na condição experimental A, o acerto era contingente a distribuições igualitárias, já na condição experimental B, o acerto era contingente a distribuições desiguais. Os resultados mostram que o grupo 1 acertou 43% das jogadas (dividiu os recursos de acordo com a condição experimental que estava em vigor) e o grupo 2 acertou 19% das jogadas. Os resultados indicam que o fato do procedimento utilizar consequências (acertos ou erros) contingentes, porém não contíguas ao entrelaçamento do grupo, dificultou a seleção de tal entrelaçamento. Entretanto, contingências de reforçamento entrelaçadas foram selecionadas por seus produtos agregados sob controle de variáveis não controladas no experimento. Caracteriza-se este fenômeno enquanto um análogo experimental de uma metacontingência. Discute-se o procedimento utilizado, possíveis aprimoramentos deste e a complexidade da tarefa experimental, além, também, de discutir alguns padrões de regras supersticiosas que emergiram durante o experimento.

Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Experimental Evaluation of the Influence of Human-Structure Interaction for Vibration Serviceability

The effects of human-structure interaction on the dynamic performance of occupied structures have long been observed. The inclusion of the effects of human-structure interaction is important to ensure that the dynamic response of a structure is not overestimated. Previous observations, both in service and in the laboratory, have yielded results indicating that the effects are dependent on the natural frequency of the structure, the posture of the occupants, and the mass ratio of the occupants to the structure. These results are noteworthy, but are limited in their application,because the data are sparse and are only pertinent to a specific set of characteristics identified in a given study. To examine these characteristics simultaneously and consistently, an experimental test structure was designed with variable properties to replicate a variety of configurations within a controlled setting focusing on the effects of passive occupants. Experimental modal analysis techniques were employed to both the empty and occupied conditions of the structure and the dynamic properties associated with each condition were compared. Results similar to previous investigations were observed, including both an increase and a decrease in natural frequency of the occupied structure with respect to the empty structure, as well as the identification of a second mode of vibration. The damping of the combined system was higher for all configurations. Overall, this study provides a broad data set representing a wide array of configurations. The experimental results of this study were used to assess current recommendations for the dynamic properties of a crowd to analytically predict the effects of human-structure interaction. The experimental results were used to select a set of properties for passive, standing occupants and develop a new model that can more accurately represent the behavior of the human-structure system as experimentally measured in this study.

Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model

ABSTRACT: BACKGROUND: Experimental studies provide evidence that inhaled nanoparticles may translocate over the airspace epithelium and cause increased cellular inflammation. Little is known, however, about the dependence of particle size or material on translocation characteristics, inflammatory response and intracellular localization. RESULTS: Using a triple cell co-culture model of the human airway wall composed of epithelial cells, macrophages and dendritic cells we quantified the entering of fine (1 mum) and nano-sized (0.078 mum) polystyrene particles by laser scanning microscopy. The number distribution of particles within the cell types was significantly different between fine and nano-sized particles suggesting different translocation characteristics. Analysis of the intracellular localization of gold (0.025 mum) and titanium dioxide (0.02-0.03 mum) nanoparticles by energy filtering transmission electron microscopy showed differences in intracellular localization depending on particle composition. Titanium dioxide nanoparticles were detected as single particles without membranes as well as in membrane-bound agglomerations. Gold nanoparticles were found inside the cells as free particles only. The potential of the different particle types (different sizes and different materials) to induce a cellular response was determined by measurements of the tumour necrosis factor-alpha in the supernatants. We measured a 2-3 fold increase of tumour necrosis factor-alpha in the supernatants after applying 1 mum polystyrene particles, gold nanoparticles, but not with polystyrene and titanium dioxide nanoparticles. CONCLUSION: Quantitative laser scanning microscopy provided evidence that the translocation and entering characteristics of particles are size-dependent. Energy filtering transmission electron microscopy showed that the intracellular localization of nanoparticles depends on the particle material. Both particle size and material affect the cellular responses to particle exposure as measured by the generation of tumour necrosis factor-alpha.

Functional assessment of collaterals in the human coronary circulation.

The coronary collateral circulation is an alternative source of blood supply to a myocardial area jeopardized by the failure of the stenotic or occluded vessel to provide enough blood flow to this region. Until recently, only qualitative or semiqualitative methods have been available for the assessment of the coronary collateral circulation in humans, such as the patient's history of walk-through angina pectoris, the registration of intracoronary ECG signs for myocardial ischaemia or angina pectoris during coronary occlusion, or coronary angiographic classification (score 0-3) of collaterals. Studies of coronary wedge pressure measurements distal of a balloon-occluded coronary artery and the recent advent of ultrathin pressure and Doppler angioplasty guidewires have made it possible to obtain pressure or flow velocity data in remote vascular areas and, thus, to calculate functional variables for coronary collateral flow. Those coronary occlusive pressure- and flow velocity-derived parameters express collateral flow as a fraction of antegrade coronary flow during vessel patency of the collateral-receiving vessel. They are both interchangeable, and they have been validated in comparison to 'traditional' methods and against each other. The possibility of accurately measuring coronary collateral flow indices in humans undergoing coronary balloon angioplasty opens areas of investigation of the pathogenesis, pathophysiology and therapeutic promotion of the collateral circulation previously reserved for exclusively experimental studies. The purpose of this article is to review several clinically available methods for the functional characterization of the coronary collateral circulation.

Establishment of a confluent monolayer model with human primary trophoblast cells: novel insights into placental glucose transport

STUDY HYPOTHESIS Using optimized conditions, primary trophoblast cells isolated from human term placenta can develop a confluent monolayer in vitro, which morphologically and functionally resembles the microvilli structure found in vivo. STUDY FINDING We report the successful establishment of a confluent human primary trophoblast monolayer using pre-coated polycarbonate inserts, where the integrity and functionality was validated by cell morphology, biophysical features, cellular marker expression and secretion, and asymmetric glucose transport. WHAT IS KNOWN ALREADY Human trophoblast cells form the initial barrier between maternal and fetal blood to regulate materno-fetal exchange processes. Although the method for isolating pure human cytotrophoblast cells was developed almost 30 years ago, a functional in vitro model with primary trophoblasts forming a confluent monolayer is still lacking. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Human term cytotrophoblasts were isolated by enzymatic digestion and density gradient separation. The purity of the primary cells was evaluated by flow cytometry using the trophoblast-specific marker cytokeratin 7, and vimentin as an indicator for potentially contaminating cells. We screened different coating matrices for high cell viability to optimize the growth conditions for primary trophoblasts on polycarbonate inserts. During culture, cell confluency and polarity were monitored daily by determining transepithelial electrical resistance (TEER) and permeability properties of florescent dyes. The time course of syncytia-related gene expression and hCG secretion during syncytialization were assessed by quantitative RT-PCR and enzyme-linked immunosorbent assay, respectively. The morphology of cultured trophoblasts after 5 days was determined by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Membrane makers were visualized using confocal microscopy. Additionally, glucose transport studies were performed on the polarized trophoblasts in the same system. MAIN RESULTS AND THE ROLE OF CHANCE During 5-day culture, the highly pure trophoblasts were cultured on inserts coated with reconstituted basement membrane matrix . They exhibited a confluent polarized monolayer, with a modest TEER and a size-dependent apparent permeability coefficient (Papp) to fluorescently labeled compounds (MW ∼400-70 000 Da). The syncytialization progress was characterized by gradually increasing mRNA levels of fusogen genes and elevating hCG secretion. SEM analyses confirmed a confluent trophoblast layer with numerous microvilli, and TEM revealed a monolayer with tight junctions. Immunocytochemistry on the confluent trophoblasts showed positivity for the cell-cell adhesion molecule E-cadherin, the tight junction protein 1 (ZO-1) and the membrane proteins ATP-binding cassette transporter A1 (ABCA1) and glucose transporter 1 (GLUT1). Applying this model to study the bidirectional transport of a non-metabolizable glucose derivative indicated a carrier-mediated placental glucose transport mechanism with asymmetric kinetics. LIMITATIONS, REASONS FOR CAUTION The current study is only focused on primary trophoblast cells isolated from healthy placentas delivered at term. It remains to be evaluated whether this system can be extended to pathological trophoblasts isolated from diverse gestational diseases. WIDER IMPLICATIONS OF THE FINDINGS These findings confirmed the physiological properties of the newly developed human trophoblast barrier, which can be applied to study the exchange of endobiotics and xenobiotics between the maternal and fetal compartment, as well as intracellular metabolism, paracellular contributions and regulatory mechanisms influencing the vectorial transport of molecules. LARGE-SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTERESTS This study was supported by the Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Switzerland, and the Swiss National Science Foundation (grant no. 310030_149958, C.A.). All authors declare that their participation in the study did not involve factual or potential conflicts of interests.

Heterogeneity of MUC1 expression by human breast carcinoma cell lines in vivo and in vitro

Increased expression of the epithelial mucin MUC1 has been linked to tumor aggressiveness in human breast carcinoma. Recent studies have demonstrated that overexpression of MUC1 interferes with cell-substrate and cell-cell adhesion by masking cell surface integrins and E-cadherin. Additionally, the cytoplasmic tail of MUC1 is involved in signal transduction and interactions with catenins. In the present study, we have examined the in vitro expression of MUC1 mRNA and protein in a panel of 14 human breast cancer cell lines using northern blotting, western blotting, immunocytochemistry, and flow cytometry. Considerable variability of expression was noted not only between cell lines but also within several individual lines. Many cell lines such as BT 20, KPL-1, and T47D expressed abundant MUC1 whilst others such as MDA-MB-231 and MCF-7 showed intermediate expression, and MDA-MB-435 and MDA-MB-453 expressed very low levels. Low levels of MUC1 expression were associated with decreased expression of cytokeratin and increased expression of vimentin. Additionally, 12 of the cell lines were established as xenografts in immunocompromised (SCID) mice, and MUC1 expression in both the primary tumors as well as metastases was assessed immunohistochemically. In general, in vivo expression mirrored in vitro expression, although there was reduced in vivo expression in T47D and ZR-75-1 xenografts. Although we showed no correlation between tumorigenicity or metastasis and MUC1 expression, this study will assist development of experimental models to assess the influence of MUC1 of on breast cancer progression.