Changes in the expression of cyclin dependent kinase inhibitors during differentiation of immortalized fibroblasts into adipocytes.

The mechanisms implicated in the differentiation of fibroblastic precursors into adipocytes can be analyzed in vitro using cell models, such as the 3T3-L1 cell line. Since cell differentiation involves an exit from the cell cycle, it is likely that molecules that inhibit proliferation participate in the control of adipogenesis. This study was aimed at determining the role, if any, of several cyclin-dependent kinase (CDK)-inhibitors and the transcription factor C/EBPα in the process of adipocyte differentitation. We analyzed by Western blot the expression of distinct cyclin-dependent kinase (CDK)-inhibitors and C/EBPα during various stages of differentiation of 3T3-L1 cells to adipocytes. We observed specific changes in the expression of CDK inhibitors and C/EBPα, during the various phases of adipogenesis. Levels of p15INK4B were maximal in confluent cells prior to the induction of differentiation and minimal in differentiated cells. Maximal levels of p16INK4A were detected following 48 h of differentiation treatment. Highest levels of p18INK4C were measured during the phase of cell confluence prior to treatment and in differentiated cells. p21CIP1 was expressed during the exponential growth phase, during exit from clonal expansion, and in differentiated cells, while p27KIP1 was found above all in confluent and differentiated cells. The present results support the participation of CDK-inhibitors in the process of in vitro adipogenesis. Specifically, the proteins p18INK4C, p21CIP1 and p27KIP1 seem to play an outstanding role in the maintenance of the differentiated state of adipocytes. Understanding the molecular mechanisms involved in adipocyte differentiation will presumably facilitate the design of new drugs aimed at novel therapeutic targets.

Efficient organic distributed feedback lasers with imprinted active films.

We report on the fabrication of efficient organic distributed feedback (DFB) lasers with thermally-nanoimprinted active films, emitting between 565 and 580 nm. The use of thermal-NIL has allowed, as opposed to room temperature or solvent-assisted techniques, high grating quality and excellent modulation depth. The 155°C heat exposure of the NIL process, does not significantly affect the thermal and optical properties of the active material (polystyrene films doped with a perylenediimide derivative). These devices combine a simple and low-cost preparation method with good laser characteristics, i.e. thresholds of 1 µJ/pulse, single-mode emission with linewidths below 0.2 nm and photostability half-lives of ~ 105 pump pulses under ambient conditions. In comparison to more standard DFBs with gratings on the substrate, their fabrication is much easier, while they show a similar laser performance.

Experimental test of curvature-driven dynamics in the phase ordering of a two dimensional liquid crystal.

We study electric field driven deracemization in an achiral liquid crystal through the formation and coarsening of chiral domains. It is proposed that deracemization in this system is a curvature-driven process. We test this prediction using the recently obtained exact result for the distribution of hull-enclosed areas in two-dimensional coarsening with nonconserved scalar order parameter dynamics [J. J. Arenzon et al., Phys. Rev. Lett. 98, 145701 (2007)]. The experimental data are in very good agreement with the theory. We thus demonstrate that deracemization in such bent-core liquid crystals belongs to the Allen-Cahn universality class, and that the exact formula, which gives us the statistics of domain sizes during coarsening, can also be used as a strict test for this dynamic universality class.

TTF-based bent-core liquid crystals.

The synthesis and characterization of bent-core liquid crystals which incorporate TTF groups is reported; different bent-core mesophases are induced depending on the molecular structure and properties derived from their compact packing have been studied.

p53 and cyclin D1 as prognostic factors in squamous cell carcinoma of the larynx.

OBJECTIVES/HYPOTHESIS: Proteins p53 and cyclin D1 play a crucial role in cell cycle control. Protein p53 mutations are one of the most common genetic alterations in human cancer, and cyclin D1 gene amplification has been found to be associated with poor prognosis in different types of tumors. Functional alterations of these proteins may play an important role both in the carcinogenesis of squamous carcinomas of the head and neck and in the clinical evolution of these tumors. The objective of the present study was to evaluate whether the presence of p53 and/or cyclin D1 proteins (detected by immunohistochemical analysis) could serve as relevant variables for the assessment of the prognosis of laryngeal squamous cell carcinoma. STUDY DESIGN: Retrospective multicentric study. METHODS: Paraffin-embedded biopsy specimens from 62 human epidermoid laryngeal carcinomas were randomly selected. The expression of p53 and cyclin D1 was examined by means of immunohistochemical analysis with a view to evaluating whether there is a correlation between the aberrant expression of these proteins and disease prognosis. RESULTS: In the sample, the presence of immunohistochemically detectable p53 is associated with shorter survival and disease-free intervals, as shown in Kaplan-Meier survival curve analysis. Indeed, multivariate statistical analysis revealed that the accumulation of p53 is an independent prognostic factor, which is associated with shorter survival. This association was not evident in the case of cyclin D1. CONCLUSION: A more precise prognosis of patients with laryngeal epidermoid carcinomas could be achieved by taking into account the presence of p53 (as assayed by immunohistochemical analysis) in biopsy tissue