Toward the renal vesicle: Ultrastructural investigation of the cap mesenchyme splitting process in the developing kidney

Background: A complex sequence of morphogenetic events leads to the development of the adult mouse kidney. In the present study, we investigated the morphological events that characterize the early stages of the mesenchymal-to-epithelial transition of cap mesenchymal cells, analyzing in depth the relationship between cap mesenchymal induction and ureteric bud (UB) branching. Design and methods: Normal kidneys of newborn non-obese diabetic (NOD) mice were excised and prepared for light and electron microscopic examination. Results: Nephrogenesis was evident in the outer portion of the renal cortex of all examined samples. This process was mainly due to the interaction of two primordial derivatives, the ureteric bud and the metanephric mesenchyme. Early renal developmental stages were initially characterized by the formation of a continuous layer of condensed mesenchymal cells around the tips of the ureteric buds. These caps of mesenchymal cells affected the epithelial cells of the underlying ureteric bud, possibly inducing their growth and branching. Conclusions: The present study provides morphological evidence of the reciprocal induction between the ureteric bud and the metanephric mesenchyme showing that the ureteric buds convert mesenchyme to epithelium that in turn stimulates the growth and the branching of the ureteric bud

Heat-damaged Fibre-Reinforced HPC: Physical and Mechanical Properties from Meso and Macro Investigations

Fire and concrete have still many issues open to investigation in terms of concrete spalling and mechanical decay at high temperature, the former mostly related to pore pressure and the latter to the addition of special constituents, like fibers and pozzolanic materials [1]. As these constituents have very different scales, the correlation between the properties measured at the micro- and macro-level stands out as a key factor to optimize cementitious mixes. Within this context, a comprehensive research project has been lately carried out in Milan and Bergamo on eleven concretes (fc = 40, 60, 90 MPa), with different aggregates (mixed, calcareous, basalt) and fiber amounts and types (vf = 0.05-0.8%; steel and pp fibers, either monofilament or fibrillated). In all mixes, the cementitious-mortar volumetric fraction was fixed (vcm = 0.40). For five reference temperatures (T = 20, 105, 250, 500 and 750°C) the properties at the micro-level were investigated by means of Thermogravimetric Analysis – TGA (to have information on free-water content, dehydration of hydrated compounds and decarbonation), X-Ray Diffraction – XRD (to determine the crystalline phases before and after heating), Mercury-Intrusion Porosimetry – MIP (to measure pore volume and size) and Scanning Electron-Microscopy - SEM (to investigate composition and possible microcracking). Also pore pressure was measured in a number of concrete slabs exposed to the standard fire on one face, with/without in-plane compressive stresses applied along the sides, to investigate concrete spalling

Activation of the protein-tyrosine kinase associated with the bombesin receptor complex in small cell lung carcinomas.

It has been hypothesized that bombesin-like peptides produced by small cell lung carcinomas may sustain deregulated proliferation through an autocrine mechanism. We have shown that the neuropeptide bombesin leads to the activation of a protein-tyrosine kinase that phosphorylates a 115-kDa protein (p115) associated with the bombesin receptor complex in mouse Swiss 3T3 fibroblasts. We now report that phosphotyrosine antibodies recognize a 115-kDa protein, phosphorylated on tyrosine, in four human small cell lung carcinoma cell lines producing bombesin but not in a nonproducer "variant" line. p115 from detergent-treated small cell lung carcinoma cells binds to bombesin-Sepharose and can be phosphorylated on tyrosine in the presence of radiolabeled ATP and Mn2+. As for the p115 immunoprecipitated from mouse fibroblast, the small cell lung carcinoma p115 can be phosphorylated in an immunocomplex kinase assay. However, the latter does not require the presence of exogenous bombesin for activity. Binding data, obtained by using radiolabeled ligand, suggest receptor occupancy in the cell lines producing bombesin. These observations are consistent with the hypothesis that proliferation in some human small cell lung carcinoma lines is under autocrine control, regulated through activation of bombesin receptors