Interfacing Sca-1(pos) mesenchymal stem cells with biocompatible scaffolds with different chemical composition and geometry.

An immortalized murine mesenchymal stem cell line (mTERT-MSC) enriched for Lin(neg)/Sca-1(pos) fraction has been obtained through the transfection of MSC with murine TERT and single-cell isolation. Such cell line maintained the typical MSC self-renewal capacity and continuously expressed MSC phenotype. Moreover, mTERT-MSC retained the functional features of freshly isolated MSC in culture without evidence of senescence or spontaneous differentiation events. Thus, mTERT-MSC have been cultured onto PLA films, 30 and 100 microm PLA microbeads, and onto unpressed and pressed HYAFF-11 scaffolds. While the cells adhered preserving their morphology on PLA films, clusters of mTERT-MSC were detected on PLA beads and unpressed fibrous scaffolds. Finally, mTERT-MSC were not able to colonize the inner layers of pressed HYAFF-11. Nevertheless, such cell line displayed the ability to preserve Sca-1 expression and to retain multilineage potential when appropriately stimulated on all the scaffolds tested.

Design and synthesis of fluorescent beta-cyclodextrins for the enantioselective sensing of alpha-amino acids.

Fluorescent monofunctionalized beta-cyclodextrins bearing a copper(II) binding side arm and a dansyl group (CD-NH-AA-CH(2)CH(2)NH-DNS) were designed as enantioselective sensors for unmodified alpha-amino acids. The side arm was derived from amino acid synthons (AA = L- and D-phenylalanine (1 and 2), L- and D-phenylglycine (3 and 4), L-proline (5), and L-cyclohexylglycine (6)) and was chosen in order to contain an amide, an amine, and a sulphonamide group. Enantioselectivity was evaluated by addition of copper(II) complexes of D- or L-valine and D- or L-proline. Chiral discrimination in the fluorescence response was observed in all cases, due to a ligand exchange process. The best conditions for these experiments were found to be the use of an excess (10:1) of the copper complex. The cyclodextrin 4 containing a D-phenylglycine unit was found to be poorly enantioselective, as found for 2, suggesting that the best design can be obtained by using L-amino acids. All L-amino acid containing cyclodextrins showed good enantioselectivities, some of which were higher than those already reported for 1. Other analytes related to amino acids were studied using cyclodextrins 1 and 3. Enantiomers of alpha,alpha-disubstituted amino acids, N-methylamino acids, and amino acid amides were found to be discriminated, while beta-phenylalanine and other molecules bearing a poor anchoring group at the alpha-carbon gave poor enantioselectivity. On the basis of the present data a model for the recognition process, based on the formation of ternary diastereomeric complexes, is proposed.

[Pneumonia in severe head injury. A prospective study]. / La polmonite nel trauma cranico grave. Uno studio prospettico.

Impairment of the state of consciousness is an important contributing factor in the onset of respiratory tract infections; in this study the data were collected prospectively to investigate the incidence and clinical implications of pneumonia in a population of head injured patients. The study was conducted on all patients treated at our centre throughout 1990. The incidence of pneumonia in the head injured was 10.8% versus 7.3% in the rest of the patients. Mortality in the group with pneumonia was not significantly different from the group without pneumonia. The average time of onset was on the fifth day from admission. The lung injury score (LIS) on the sixth day, the time on artificial ventilation and the length of stay in intensive care were significantly greater in those with pneumonia (1.18, 14.6 days and 21.9 days versus 0.8, 4.2 days and 12.9 days respectively). Staphylococcus was the single most frequently isolated germ. Our study concludes that pneumonia represents a relatively frequent and early complication in patients with head injury, and it is associated with prolonged artificial ventilation and longer staying in ICU.