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J Alfaro

Publications and source records attributed to J Alfaro.

40 records · Page 3Linked to original sources
PubMedDate not supplied

High encapsulation efficiencies in sized liposomes produced by extrusion of dehydration-rehydration vesicles.

In an attempt to produce sized liposomes with high encapsulation efficiency by a gentle procedure, we compared the encapsulation efficiency in liposomes of three different molecules: carboxyfluorescein (mol.wt 376 Da), protein A (mol. wt 40,000 Da), and a DNA-plasmid pN2 alpha 1AT (9.3 kb). Sized liposomes were obtained by extrusion of multilamellar vesicles through polycarbonate filters of defined pore size (0.2 micron). Multilamellar vesicles were formed by mechanical dispersion of dried egg phosphatidylcholine (PC) and cholesterol (CH) at molar ratio 1:1 in an aqueous buffer (MLVs) or by dehydration-rehydration procedure (DRVs) where small unilamellar vesicles (SUVs) obtained by probe sonication of PC:CH (1:1) in water were dried in the presence of the desired agent by lyophilization and then rehydrated in one tenth of the original volume. Our results show that, in all cases, the higher encapsulation efficiencies were obtained by dehydration-rehydration vesicles (DRVs) and that the ratio material/lipid in sized DRVs (S-DRVs) increased three- to four-fold with respect to sized liposomes (S-MLV) obtained by extrusion of MLVs. In addition, plasmid electrophoresis on agarose gels (0.8 per cent) showed that no detectable DNA fracture was produced in the encapsulation process. In summary, we showed that extrusion through polycarbonate filters of preformed DRVs is a gentle procedure which enhances the encapsulation efficiencies in sized liposomes of molecules with clearly different molecular weight and structure.

Capsules↗
PubMedDate not supplied

Treatment of adolescent Blount disease by asymmetric physeal distraction.

An alternative treatment is presented for late-onset Blount disease in a 14-year-old boy. The technique consists of asymmetric physeal distraction of the proximal tibial growth plate by using a modified Wagner fixator-distractor device that allows progressive angular correction. The patient had a 23 degrees varus deviation of the left tibia, and no physeal bone bridges were detected. Once the fixator was assembled, distraction started 24 h after surgery at a rate of 1.5 mm/day (2 x 0.75). Complete correction was achieved in 25 days. No osteotomy of the fibula was required. The Wagner device was removed in the outpatient clinic 10 weeks postoperatively. After a 4-year follow-up, there was no loss of correction, showing a satisfactory alignment of the operated-on lower extremity. As compared with acute conventional osteotomies, asymmetric physeal distraction entails several advantages for treatment of Blount disease such as less invasive surgery, progressive and adjustable correction taking place at the apex of the deformity, and the possibility of bone lengthening if needed. Furthermore, physeal distraction does not require a second surgical step for bonegraft harvesting or for removal of the internal fixation.

Adolescent↗