Transcriptional regulation of Sox2 by the retinoblastoma family of pocket proteins

Cellular reprogramming to iPSCs has uncovered unsuspected links between tumor suppressors and pluripotency factors. Using this system, it was possible to identify tumor suppressor p27 as a repressor of Sox2 during differentiation. This led to the demonstration that defects in the repression of Sox2 can contribute to tumor development. The members of the retinoblastoma family of pocket proteins, pRb, p107 and p130, are negative regulators of the cell cycle with tumor suppressor activity and with roles in differentiation. In this work we studied the relative contribution of the retinoblastoma family members to the regulation of Sox2 expression. We found that deletion of Rb or p130 leads to impaired repression of Sox2, a deffect amplified by inactivation of p53. We also identified binding of pRb and p130 to an enhancer with crucial regulatory activity on Sox2 expression. Using cellular reprogramming we tested the impact of the defective repression of Sox2 and confirmed that Rb deficiency allows the generation of iPSCs in the absence of exogenous Sox2. Finally, partial depletion of Sox2 positive cells reduced the pituitary tumor development initiated by Rb loss in vivo. In summary, our results show that Sox2 repression by pRb is a relevant mechanism of tumor suppression.     

Impaired Agency in Schizophrenia: Family Therapy with a Young Adult Patient

ABSTRACT

This article illustrates the value of utilizing brief psychodynamically oriented interventions to examine how problematic family dynamics exacerbate underlying internal deficits in a young adult with schizophrenia. The propensity for enactments to occur in psychodynamic family therapy is also emphasized. A clinical example illustrates the family therapist's capacity to detect and understand the potential for an enactment, to remain differentiated from the family, and to make conscious the family's unconscious defensive behaviors, which allows family members to begin to recognize the ways in which they are caught in loyalty binds that may inhibit the development of a personal sense of agency by the young adult.     

Removal of Au3+ and Ag+ from aqueous media with magnetic nanoparticles functionalized with squaramide derivatives

New magnetic hybrid nanoparticles of Fe₃O₄ coated with organosulfur-squaramide compounds are prepared. The modified-nanoparticles show a good coordination for Ag⁺ and Hg²⁺ cations in water, and present a high affinity for Au³⁺ ions. The behaviour of the squaramide-coated nanoparticles differs significantly from that previously reported for nanoparticles used as Au³⁺ scavengers. In the presence of organosulfur-squaramide, the Au³⁺ salt is reduced to gold nanoparticles that are deposited upon Fe₃O₄ nanoparticles. For the first time, the coordination capacity of the carbonyl squaramide groups with the gold cation, based on purely electrostatic cation–dipole interactions, is proved.

An efficient methodology, based on squaramide-coated magnetite nanoparticles, for the removal of Au³⁺ and Ag⁺ by magneto filtration from water.     

Dimensional accuracy of small gold alloy castings. Part 1. A brief history and the behaviour of inlay waxes

Part 1 reviews published studies which relate to materials and techniques contributing to the dimensional accuracy of small dental castings. A brief history of the cire perdue or lost-wax method of casting alloys and the development of modern dental casting materials and techniques are presented. Data on the behaviour of inlay wax, in particular its contraction and distortion, are reviewed as is the extensive literature about the casting shrinkage of gold alloys (Part 2) and the setting and thermal expansion of investments under both laboratory and practical conditions (Part 3). Part 4 discusses the role of the casting ring and its asbestos liner. Asbestos as a liner has now largely been replaced by two alternative materials, one based on cellulose and the other on ceramic fibres. The limited literature on the effect of these newer materials on casting accuracy is also reviewed, as their introduction may require significant changes in the traditional technology of dental casting.     

The effect of potential investment expansion and hot strength on the fit of full-crown castings made with a gypsum-bonded investment

Objectives. It has been claimed that the strength of the investment mold at the casting temperature affects the dimensional accuracy of castings (e.g., Markley, 1953; Earnshaw, 1957; Asgar, 1972), but the relationship has not been studied quantitatively. In this investigation, the effects of both mold expansion and hot strength on the relative inaccuracy of full-crown castings have been measured and analyzed. The likelihood that a strong investment could cause distortion of the casting by non-uniform restriction of casting shrinkage (Earnshaw, 1969b) was also considered.Methods. Castings were made with a commercial gypsum-bonded inlay investment, used both as supplied and with modifications that increased its expansion and reduced its hot strength. In both series of tests, the investments were used over a wide range of liquid/powder (L/P) ratios in casting rings fitted with dry ceramic liners, and set under dry conditions.Results. Casting inaccuracy showed a significant linear correlation with total expansion and a highly significant linear correlation with the combination of total expansion and hot strength. The modified investment, with its low hot strength, gave less distortion of casting shape than did the much stronger unmodified material. However, it was found that to ensure sound castings, the hot compressive strength should not be less than 1.8 MPa.Significance. This investigation showed that while investment expansion is the major variable affecting casting inaccuracy, hot strength is an important modifying factor which also has to be considered when predicting casting inaccuracy from measured properties of the investment.