Characterization and localization of primordial germ cells in Totoaba macdonaldi.

The totoaba, Totoaba macdonaldi, is an endangered fish of the Gulf of California with high economic and ecological potential. Therefore, our purpose was to characterize the Primordial Germ Cells (PGCs) of this Sciaenid with two objectives: (1) to provide the basis for PGCs cryopreservation to preserve the genetic resources and (2) to take the first step to know the gonadal genesis and sex differentiation of totoaba. Immunofluorescence analysis performed from 2-cell stage to 8-day after hatch (DAH) shows that Vasa protein is specific for PGCs. These cells were first observed in the peripheral and dorsal regions of the blastodisc at approximately the 50%-epiboly stage and migrated to both sides of embryo body during the development. Finally, at 7 DAH the PGCs of the hatching embryo reached the place where the gonad will be developed. Histology analysis of larvae showed a genital ridge with enclosed PGCs on the dorsal side of the peritoneum at 9 DAH, gonadal primordium growth was observed at 11 DAH as a result of the interaction between PGCs and somatic cells derived from the peritoneum. Results of qPCR showed that vasa expression was restricted to the embryonic and early larval development, highest values were observed in 2-cell and mid-blastula stage suggesting the maternal inheritance of vasa mRNA. These findings support the hypothesis of preformation in T. macdonaldi PGCs. The migration pattern of PGCs allow us to recommend the isolation and subsequent cryopreservation of these cells before 7 DAH when the embryonic and larval development is given at 21 °C.

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.

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