F Rustichelli — Page 2

PubMed1985

X-ray diffractometry and calorimetry studies of structural modifications induced by gamma-irradiation in phosphatidylcholine multilamellar liposomes.

Experimental results are reported on structural and thermodynamic modifications induced by gamma-irradiation in model membranes. Differential scanning calorimetry (DSC) and X-ray diffraction were used to study the different phases and associated transitions of dipalmitoylphosphatidylcholine after 60Co gamma-irradiation. Changes were observed in the shape of calorimetric peaks and in the corresponding enthalpy. The repetition distance of the layers increases while the distances related to the aliphatic chains decrease as a function of gamma-irradiation time. Moreover, an increase in the hexagonal symmetry with increasing dose was detected. No disappearance of a pre-transition was detected even at high doses.

Calorimetry↗

PubMedDate not supplied

Synchrotron radiation microtomography of bone engineered from bone marrow stromal cells.

Osteoprogenitor cells expanded in vitro and associated with porous ceramic scaffolds have been proposed as bone substitutes. Animal models have been developed to test the efficacy of various cell populations and scaffolds in promoting bone repair. Qualitative analysis of the new bone formed within the ceramic scaffold is relatively easy by conventional histology. On the other hand, quantitative data are difficult to obtain. X-ray computed microtomography was used as a possible experimental technique to obtain quantitative data on the three-dimensional structure of newly formed bone and of remaining scaffold in implants after 8 weeks in vivo. Measurements were performed at the European Synchrotron Radiation Facility on beamline ID19 with a spatial resolution of about 5 microm. This study clearly indicates the possibility of nondestructive quantitative analysis of bone-engineered constructs. The technique appears suitable to compare different scaffolds (and possibly different cell populations) with regard to bone formation efficiency and reabsorbability of biomaterials in the immunodeficient mouse model.

Absorptiometry, Photon↗