Theoretical Validity and Empirical Utility of a Constructionist Analytics

Wing-Chung Ho offers an extensive critique of what he calls our “radical constructionist approach to family experience,” questioning the theoretical validity and empirical utility of the research program. This article responds to the charges in the broader context of the program\u27s constructionist analytics, discussing family\u27s experiential location, organizational embeddedness, and the importance of ethnographic sensibility. A brief extract of situated talk and interaction is presented to illustrate the discursive complexity and institutional bearings of family as a category of experience. The conclusion takes up the issue of whether the program is radical in conceptualization and empirical realization

Don\u27t Argue with the Members

Mel Pollner regularly cautioned researchers not to argue with the members of settings under consideration. He warned against substituting the researcher’s meaning for the meanings of those being studied. This article discusses facets of the caution as they relate to the research process. Seemingly simple, the tenet is nuanced in application. The article adds to the nuance by distinguishing what is called the “replacement” of meaning with the “displacement” of meaning, providing a way of understanding what members could mean if the contexts and settings of their accounts were taken into consideration

Animating Interview Narratives

This chapter discusses the implications of viewing the interview as an actively constructed conversation through which narrative data are produced. It explores the ramifications of framing the interview and resulting data as by-products of interpretive practice - the whats and hows of an animated process involving active subjects behind interview participants. Matters of reliability, validity, bias, and rigor are considered

The Role of Osteocytes in Targeted Bone Remodeling: A Mathematical Model

Until recently many studies of bone remodeling at the cellular level have focused on the behavior of mature osteoblasts and osteoclasts, and their respective precursor cells, with the role of osteocytes and bone lining cells left largely unexplored. This is particularly true with respect to the mathematical modeling of bone remodeling. However, there is increasing evidence that osteocytes play important roles in the cycle of targeted bone remodeling, in serving as a significant source of RANKL to support osteoclastogenesis, and in secreting the bone formation inhibitor sclerostin. Moreover, there is also increasing interest in sclerostin, an osteocyte-secreted bone formation inhibitor, and its role in regulating local response to changes in the bone microenvironment. Here we develop a cell population model of bone remodeling that includes the role of osteocytes, sclerostin, and allows for the possibility of RANKL expression by osteocyte cell populations. This model extends and complements many of the existing mathematical models for bone remodeling but can be used to explore aspects of the process of bone remodeling that were previously beyond the scope of prior modeling work. Through numerical simulations we demonstrate that our model can be used to theoretically explore many of the most recent experimental results for bone remodeling, and can be utilized to assess the effects of novel bone-targeting agents on the bone remodeling process

Cell cycle length, cell size, and proliferation rate in hydra stem cells

We have analyzed the cell cycle parameters of interstitial cells in Hydra oligactis. Three subpopulations of cells with short, medium, and long cell cycles were identified. Short-cycle cells are stem cells; medium-cycle cells are precursors to nematocyte differentiation; long-cycle cells are precursors to gamete differentiation. We have also determined the effect of different cell densities on the population doubling time, cell cycle length, and cell size of interstitial cells. Our results indicate that decreasing the interstitial cell density from 0.35 to 0.1 interstitial cells/epithelial cell (1) shortens the population doubling time from 4 to 1.8 days, (2) increases the [3H]thymidine labeling index from 0.5 to 0.75 and shifts the nuclear DNA distribution from G2 to S phase cells, and (3) decreases the length of G2 in stem cells from 6 to 3 hr. The shortened cell cycle is correlated with a significant decrease in the size of interstitial stem cells. Coincident with the shortened cell cycle and increased growth rate there is an increase in stem cell self-renewal and a decrease in stem cell differentiation

Luminal Ca2+ depletion during the unfolded protein response in Xenopus oocytes: Cause and consequence

The endoplasmic reticulum (ER) is a Ca2+ storing organelle that plays a critical role in the synthesis, folding and post-translational modifications of many proteins. The ER enters into a condition of stress when the load of newly synthesized proteins exceeds its folding and processing capacity. This activates a signal transduction pathway called the unfolded protein response (UPR) that attempts to restore homeostasis. The precise role of ER Ca2+ in the initiation of the UPR has not been defined. Specifically, it has not been established whether ER Ca2+ dysregulation is a cause or consequence of ER stress. Here, we report that partial depletion of ER Ca2+ stores induces a significant induction of the UPR, and leads to the retention of a normally secreted protein Carboxypeptidase Y. Moreover, inhibition of protein glycosylation by tunicamycin rapidly induced an ER Ca2+ leak into the cytosol. However, blockade of the translocon with emetine inhibited the tunicamycin-induced Ca2+ release. Furthermore, emetine treatment blocked elF2α phosphorylation and reduced expression of the chaperone BiP. These findings suggest that Ca2+ may be both a cause and a consequence of ER protein misfolding. Thus, it appears that ER Ca2+ leak is a significant co-factor for the initiation of the UPR.Fil: Paredes, R. Madelaine. University of Texas; Estados UnidosFil: Bollo, Mariana Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Holstein, Deborah. University of Texas; Estados UnidosFil: Lechleiter, James D.. University of Texas; Estados Unido