Chapter 13 Rebuilding Relationships between Data, Method, and Theories

In both Management and I/O Psychology, contributions to theory remain an important, and in many cases, sole criterion for evaluating submissions to top journals. In many ways, the definition of theory and the primacy of theory in the organizational sciences is an outlier; in most sciences, articles rarely even mention theories, much less build themselves around advancing theory. We propose that the classic description of the scientific methods provides a better guide to understanding the relationships between data, methods and theory than our current model, which often starts and ends with proposing a theory, which may never again be referenced or tested. We describe a pyramid of types of evidence that is useful for assessing the reliability and worth of particular sorts of data and show how this approach to evidence informs the scientific method and assists in identifying and building useful theories

Chapter 13 Rebuilding Relationships between Data, Method, and Theories

In both Management and I/O Psychology, contributions to theory remain an important, and in many cases, sole criterion for evaluating submissions to top journals. In many ways, the definition of theory and the primacy of theory in the organizational sciences is an outlier; in most sciences, articles rarely even mention theories, much less build themselves around advancing theory. We propose that the classic description of the scientific methods provides a better guide to understanding the relationships between data, methods and theory than our current model, which often starts and ends with proposing a theory, which may never again be referenced or tested. We describe a pyramid of types of evidence that is useful for assessing the reliability and worth of particular sorts of data and show how this approach to evidence informs the scientific method and assists in identifying and building useful theories

Communicating Criterion-Related Validity Using Expectancy Charts: A New Approach

Often, personnel selection practitioners present the results of their criterion-related validity studies to their senior leaders and other stakeholders when trying to either implement a new test or validate an existing test. It is sometimes challenging to present complex, statistical results to non-statistical audiences in a way that enables intuitive decision making. Therefore, practitioners often turn to expectancy charts to depict criterion-related validity. There are two main approaches for constructing expectancy charts (i.e., use of Taylor-Russell tables or splitting a raw dataset), both of which have considerable limitations. We propose a new approach for creating expectancy charts based on the bivariate-normal distribution. The new method overcomes the limitations inherent in the other two methods and offers a statistically sound and user-friendly approach for constructing expectancy charts

Zebrafish embryo extracts enhance 5-FU anti-cancer effects upon breast cancer cells

OBJECTIVE: The inhibition of the metastatic capability of cancer cells is a pivotal aim of current anticancer strategies. We investigated herein the anti-migrating and anti-invasive properties of Zebrafish embryo extracts (SL) - an integrative formula comprising morphogenetic factors extracted from zebrafish embryos - alone or in association with 5-Fluoro-Uracil (5-FU), when added to metastatic breast cancer cells (MDA-MB-231) and in normal epithelial breast cells (MCF10A) committed toward an inflammatory phenotype upon TGF-beta 1 stimulation.MATERIALS AND METHODS: Invasiveness, migrating capability, cytoskeleton architecture and related molecular factors involved in the epithelial-mesenchymal transition were studied after treatment with 5-FU, with and without SL.RESULTS: Remarkably, in both circumstances, embryo extracts amplify the migratory inhibition triggered by the anticancer drug 5-Fu. The fact that such an effect is noticed in normal as well as in cancerous cells suggests that the critical target of embryo extracts is specifically represented by the migrating/invasive phenotype. However, while 5-FU was unable in antagonizing the invasiveness of cancerous cells, the association with SL can significantly impair the invasive capability of tumor cells. These findings are noticeably associated with the reversion of the EMT phenotype in SL-treated cells, as documented by the contemporary downregulation of TCTP and some EMT-related molecular effectors, like alpha-SMA and Vimentin.CONCLUSIONS: Embryo fish extracts significantly counteract the migrating and invasive phenotype of cancerous and inflammatory breast cells treated with the chemotherapeutic drug 5-FU. The availability of a compound able to amplify 5-Fu activity while significantly hampering the invasive phenotype of breast cancer should provide invaluable benefits, namely if we consider that this compound is substantially deprived of side-effects

Zebrafish embryo extracts enhance 5-FU anti-cancer effects upon breast cancer cells

– OBJECTIVE: The inhibition of the metastatic capability of cancer cells is a pivotal aim of current anticancer strategies. We investigated herein the anti-migrating and anti-invasive properties of Zebrafish embryo extracts (SL) – an integrative formula comprising morphogenetic factors extracted from zebrafish embryos – alone or in association with 5-Fluoro-Uracil (5-FU), when added to metastatic breast cancer cells (MDA-MB-231) and in normal epithelial breast cells (MCF10A) committed toward an inflammatory phenotype upon TGF-β1 stimulation. MATERIALS AND METHODS: Invasiveness, migrating capability, cytoskeleton architecture and related molecular factors involved in the epithelial-mesenchymal transition were studied after treatment with 5-FU, with and without SL. RESULTS: Remarkably, in both circumstances, embryo extracts amplify the migratory inhibition triggered by the anticancer drug 5-Fu. The fact that such an effect is noticed in normal as well as in cancerous cells suggests that the critical target of embryo extracts is specifically represented by the migrating/invasive phenotype. However, while 5-FU was unable in antagonizing the invasiveness of cancerous cells, the association with SL can significantly impair the invasive capability of tumor cells. These findings are noticeably associated with the reversion of the EMT phenotype in SL-treated cells, as documented by the contemporary downregulation of TCTP and some EMT-related molecular effectors, like α-SMA and Vimentin. CONCLUSIONS: Embryo fish extracts significantly counteract the migrating and invasive phenotype of cancerous and inflammatory breast cells treated with the chemotherapeutic drug 5-FU. The availability of a compound able to amplify 5-Fu activity while significantly hampering the invasive phenotype of breast cancer should provide invaluable benefits, namely if we consider that this compound is substantially deprived of side-effects

Article microgravity induces transient emt in human keratinocytes by early down-regulation of e-cadherin and cell-adhesion remodeling

Changes in cell–matrix and cell-to-cell adhesion patterns are dramatically fostered by the microgravity exposure of living cells. The modification of adhesion properties could promote the emergence of a migrating and invasive phenotype. We previously demonstrated that short exposure to the simulated microgravity of human keratinocytes (HaCaT) promotes an early epithelial– mesenchymal transition (EMT). Herein, we developed this investigation to verify if the cells maintain the acquired invasive phenotype after an extended period of weightlessness exposure. We also evaluated cells’ capability in recovering epithelial characteristics when seeded again into a normal gravitational field after short microgravity exposure. We evaluated the ultra-structural junctional features of HaCaT cells by Transmission Electron Microscopy and the distribution pattern of vinculin and E-cadherin by confocal microscopy, observing a rearrangement in cell–cell and cell–matrix interactions. These results are mirrored by data provided by migration and invasion biological assay. Overall, our studies demonstrate that after extended periods of microgravity, HaCaT cells recover an epithelial phenotype by re-establishing E-cadherin-based junctions and cytoskeleton remodeling, both being instrumental in promoting a mesenchymal–epithelial transition (MET). Those findings suggest that cytoskeletal changes noticed during the first weightlessness period have a transitory character, given that they are later reversed and followed by adaptive modifications through which cells miss the acquired mesenchymal phenotype

Survival pathways are differently affected by microgravity in normal and cancerous breast cells

Metazoan living cells exposed to microgravity undergo dramatic changes in morphological and biological properties, which ultimately lead to apoptosis and phenotype reprogramming. However, apoptosis can occur at very different rates depending on the experimental model, and in some cases, cells seem to be paradoxically protected from programmed cell death during weightlessness. These controversial results can be explained by considering the notion that the behavior of adherent cells dramatically diverges in respect to that of detached cells, organized into organoids-like, floating structures. We investigated both normal (MCF10A) and cancerous (MCF-7) breast cells and found that appreciable apoptosis occurs only after 72 h in MCF-7 cells growing in organoid-like structures, in which major modifications of cytoskeleton components were observed. Indeed, preserving cell attachment to the substrate allows cells to upregulate distinct Akt- and ERK-dependent pathways in MCF-7 and MCF-10A cells, respectively. These findings show that survival strategies may differ between cell types but cannot provide sufficient protection against weightlessness-induced apoptosis alone if adhesion to the substrate is perturbed

Analysis of the gastrin-releasing peptide receptor gene in Italian patients with autism spectrum disorders

The gastrin-releasing peptide receptor (GRPR) was implicated for the first time in the pathogenesis of Autism spectrum disorders (ASD) by Ishikawa-Brush et al. [Ishikawa-Brush et al. (1997): Hum Mol Genet 6: 1241-1250]. Since this original observation, only one association study [Marui et al. (2004): Brain Dev 26: 5-7] has further investigated, though unsuccessfully, the involvement of the GRPR gene in ASD. With the aim of contributing further information to this topic we have sequenced the entire coding region and the intron/exon junctions of the GRPR gene in 149 Italian autistic patients. The results of this study led to the identification of four novel point mutations, two of which, that is, C6S and L181F, involve amino acid changes identified in two patients with ASD and Rett syndrome, respectively. Both the leucine at position 181 and the cysteine at position 6 are strongly conserved in vertebrates. C6S and L181F mutant proteins were expressed in COS-7 and BALB/3T3 cells, but they did not affect either GRP's binding affinity or its potency for stimulating phospholipase C-mediated production of inositol 1,4,5-trisphosphate. In summary, our results do not provide support for a major role of the GRPR gene in ASD in the population of patients we have studied. However, there is a potential role of C6S and L181F mutations on GRPR function, and possibly in the pathogenesis of the autistic disorders in the two patient

Microgravity Modifies the Phenotype of Fibroblast and Promotes Remodeling of the Fibroblast–Keratinocyte Interaction in a 3D Co-Culture Model

Microgravity impairs tissue organization and critical pathways involved in the cell– microenvironment interplay, where fibroblasts have a critical role. We exposed dermal fibroblasts to simulated microgravity by means of a Random Positioning Machine (RPM), a device that reproduces conditions of weightlessness. Molecular and structural changes were analyzed and compared to control samples growing in a normal gravity field. Simulated microgravity impairs fibroblast conversion into myofibroblast and inhibits their migratory properties. Consequently, the normal interplay between fibroblasts and keratinocytes were remarkably altered in 3D co-culture experiments, giving rise to several ultra-structural abnormalities. Such phenotypic changes are associated with down-regulation of α-SMA that translocate in the nucleoplasm, altogether with the concomitant modification of the actin-vinculin apparatus. Noticeably, the stress associated with weightlessness induced oxidative damage, which seemed to concur with such modifications. These findings disclose new opportunities to establish antioxidant strategies that counteract the microgravity-induced disruptive effects on fibroblasts and tissue organization

Carbon nanotubes toxicology and effects on metabolism and immunological modification in vitro and in vivo

The aim of this research is focused on the biological effects of multi wall carbon nanotubes (MWCNTs) on three different human cell types, laboratory animals in vivo, and immunological effects. Large numbers of researchers are directly involved in the handling of nanostructured materials such as MWCNTs and nanoparticles. It is important to assess the potential health risks related to their daily exposure to carbon nanotubes. The administration of sterilized nanosamples has been performed on laboratory animals, in both acute and chronic administration, and the pathological effects on the parenchymal tissues have been investigated. We studied the serum immunological modifications after intraperitoneal administration of the MWCNTs. We did not observe any antigenic reaction; the screening of ANA, anti-ENA, anti-cardiolipin, C-ANCA and P-ANCA was negative. No quantitative modification of immunoglobulins was observed, hence no modification of humoral immunity was documented. We also studied the effects of MWCNTs on the proliferation of three different cell types. MCF-7 showed a significant inhibition of proliferation for all conditions studied, whereas hSMCs demonstrated a reduction of cell growth only for the highest MWCNTs concentrations after 72 h. Also, no growth modification was observed in the Caco-2 cell line. We observed that a low quantity of MWCNTs does not provoke any inflammatory reaction. However, for future medical applications, it is important to realize prosthesis based on MWCNTs, through studying the corresponding implantation effects. Moreover, it has to be emphasized that this investigation does not address, at the moment, the carcinogenicity of MWCNTs, which requires a detailed follow-up investigation on the specific topic. In view of the subsequent and more extensive use of MWCNTs, especially in applications where carbon nanotubes are injected into the human body for drug delivery, as a contrast agent carrying entities for MRI, or as the basic material of a new prosthesis generation, more extended tests and experiments are necessary. © 2008 IOP Publishing Ltd