[Ultrasound bone densitometry in children and adolescents; Italian refence curves with multi-site device (Omnisense)]. / Densitometria ossea a ultrasuoni in età pediatrica: creazione di un database in una popolazione italiana con densitometro multi-sede Omnisense (Sunlight Technologies).

The values of bone density represent one of the best parameters for the prediction of the risk of fracture in the adult. Since the peak of bone mass depends over that on genetic factors also on modifiable environmental factors, the evaluation of the state of bone health in paediatric populations has assumed great importance; the ultrasound techniques seem to represent a potential alternative to DXA and QTC. Using Omnisense device (Omnisense, Sunlight Ultrasound Technologies) we have evaluated the bone strength in a champion of 652 children and teen-agers aged 6-18 (328 females, 324 males). The measurements have been made at the distal third of the radius and midshaft tibia. The purpose has been to record the values of SOS in a healthy paediatric population, building a normal database and to find a correlation between the SOS values and anthropometric data, dietary factors and physical activity. The comparison with an analogous study conducted by other Authors prompted us to conclude that in the paediatric population the construction of proper curves of reference, with which to compare the data of the patients, is essential to avoid errors in the evaluation of bone density, in agreement with how much already underlined in literature. Besides a correct interpretation of the data obtained with ultrasounds systems asks for a change of the thresholds values established by the OMS for the diagnosis of osteopenia/osteoporosis with the DXA. As already happened for the adult population in children also it will be therefore necessary to compare a great number of pathological subjects with the normal database, establishing so the new values of Z-Score and giving a clinical meaning to the effected measurements.

Enantiomer separation of alpha-ionone using gas chromatography with cyclodextrin derivatives as chiral stationary phases.

The gas chromatographic enantiomer separation of alpha-ionone was studied with three different chiral stationary phases using as chiral selectors: (1) heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin, dissolved in polysiloxane PS-086, (2) octakis(2,6-di-O-pentyl-3-O-trifluoroacetyl)-gamma-cyclodextrin and (3) octakis(2,6-di-O-pentyl-3-O-butanoyl)-gamma-cyclodextrin, both dissolved in polysiloxane SE-54. The influence of the concentration of the chiral selector in the polysiloxane, coated on Chromosorb P AW-DMCS 80-100 mesh, is described and discussed, as well as the effect of Chromosorb loading. The feasibility of the preparative gas chromatographic separation of the enantiomers of alpha-ionone is considered; in order to provide a term of comparison, the estimated performances are compared with those achieved in the separation of the enantiomers of the inhalation anaesthetic enflurane.