The Complex GNAS Imprinted Locus and Mesenchymal Stem Cells Differentiation.

All tissues and organs derive from stem cells, which are undifferentiated cells able to differentiate into specialized cells and self-renewal. In mammals, there are embryonic stem cells that generate germ layers, and adult stem cells, which act as a repair system for the body and maintain the normal turnover of regenerative organs. Mesenchymal stem cells (MSCs) are nonhematopoietic adult multipotent cells, which reside in virtually all postnatal organs and tissues, and, under appropriate in vitro conditions, are capable to differentiate into osteogenic, adipogenic, chondrogenic, myogenic, and neurogenic lineages. Their commitment and differentiation depend on several interacting signaling pathways and transcription factors. Most GNAS-based disorders have the common feature of episodic de novo formation of islands of extraskeletal, qualitatively normal, bone in skin and subcutaneous fat. The tissue distribution of these lesions suggests that pathogenesis involves abnormal differentiation of MSCs and/or more committed precursor cells that are present in subcutaneous tissues. Data coming from transgenic mice support the concept that GNAS is a key factor in the regulation of lineage switching between osteoblast and adipocyte fates, and that its role may be to prevent bone formation in tissues where bone should not form. Despite the growing knowledge about the process of heterotopic ossification in rare genetic disorders, the pathophysiological mechanisms by which alterations of cAMP signaling lead to ectopic bone formation in the context of mesenchymal tissues is not fully understood.

Survey on the microbiological quality of Chinese food preparations.

The microbiological quality of 118 samples of traditional Chinese food from restaurants and take-away establishments in the provinces of Padua, Treviso, and Venice was examined (April-July, 2008). These food items included various ready-to-eat products. The microbiological quality of the majority of these food items was acceptable; only 12% of samples had values greater than or equal to 6 log CFU/g (eight items were salads) and 19% of samples had values greater than 500 CFU fecal coliforms/g (p < 0.01 to 0.001). The Aw lower values were in sauces (0.839), but were greater than 0.95 in other food sources. No pathogens, such as Salmonella spp. or Listeria monocytogenes, were detected, but Bacillus cereus and coagulase-positive Staphylococcus were both identified. Thus, although final heating reduces the levels of microorganisms present in foods, it does not inactivate any toxins produced by such organisms.