Efficient delivery of human single fiber-derived muscle precursor cells via biocompatible scaffold.

The success of cell therapy for skeletal muscle disorders depends upon two main factors: the cell source and the method of delivery. In this work we have explored the therapeutic potential of human muscle precursor cells (hMPCs), obtained from single human muscle fibers, implanted in vivo via micropatterned scaffolds. hMPCs were initially expanded and characterized in vitro by immunostaining and flow cytometric analysis. For in vivo studies, hMPCs were seeded onto micropatterned poly-lactic-glycolic acid 3D-scaffolds fabricated using soft-lithography and thermal membrane lamination. Seeded scaffolds were then implanted in predamaged tibialis anterior muscles of CD1 nude mice; hMPCs were also directly injected in contralateral limbs as controls. Similarly to what we previously described with mouse precursors cells, we found that hMPCs were able to participate in muscle regeneration and scaffold-implanted muscles contained a greater number of human nuclei, as revealed by immunostaining and Western blot analyses. These results indicate that hMPCs derived from single fibers could be a good and reliable cell source for the design of therapeutic protocols and that implantation of cellularized scaffolds is superior to direct injection for the delivery of myogenic cells into regenerating skeletal muscle.

Toxicity and efficacy of intrathecal liposomal cytarabine in children with leukemia/lymphoma relapsing in the central nervous system: a retrospective multicenter study.

The toxicity and efficacy of intrathecal liposomal cytarabine (LC) were evaluated in children with central nervous system (CNS) relapsed/refractory acute leukemia/lymphoma. Thirty patients (male:female ratio 21:9; median age 9.4 years) with CNS relapsed/resistant disease were treated with intrathecal LC at dosages adjusted for age. Twenty-seven (90%) patients simultaneously received systemic chemotherapy, including concurrent high-dose cytarabine or methotrexate in 21 (70%) cases. Of 28 patients evaluable for response, 25 patients (89%) achieved CNS complete remission and three (11%) partial remission. The median number of intrathecal LC administrations per patient was 4. The cerebrospinal fluid was cleared after a median of 3 intrathecal LC administrations. Neurological toxicity ≥ grade 3 occurred in four (13%) patients. No permanent sequelae were observed. The median overall survival was 20.9 months and the 5-year probability of survival was 46%. These encouraging data suggest that intrathecal LC is well tolerated and effective in children with relapsed/refractory CNS leukemia/lymphoma.

'In vitro' antioxidant and photoprotective properties and interaction with model membranes of three new quercetin esters.

Quercetin is well known to possess the strongest protective effect against UV light-induced lipoperoxidation. However, the absolute water insolubility of quercetin is a key step that may limit its bioavailability and, thus, its 'in vivo' employment as a photoprotective agent. The aim of the present paper was to evaluate 'in vitro' the antioxidant and photoprotective properties and the interaction with model membranes of three new semisynthetic quercetin derivatives, quercetin-3-O-acetate (Q-ac), quercetin-3-O-propionate (Q-pr) and quercetin-3-O-palmitate (Q-pal), obtained by esterification of the C-3 OH function with an aliphatic side-chain of different length. The antioxidant activity of quercetin and of its three esters was assessed in two 'in vitro' experimental models: (a) the bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; (b) UV radiation-induced peroxidation in multilamellar vesicles (MLVs). Differential scanning calorimetry on dimyristoylphosphatidylcholine MLVs and unilamellar vesicles was employed to investigate the interaction of the drugs tested with model membranes. Finally, the stability following UV light exposure and the lipophilicity and water solubility of quercetin and its three esters were examined. The findings obtained demonstrated that the esterification with an opportune aliphatic side chain of the OH function located at the C-3 position allows the production of new quercetin derivatives, which may be good candidates as photoprotective agents. In particular, one could speculate that the esterification with a short side-chain (such as in Q-ac and Q-prop) provides the suitable chemico-physical features not only to maintain the antioxidant and photoprotective effectiveness of the parent drug, but also to be able to migrate through the aqueous environment and to interact with and cross phospholipid membranes.

Differential scanning calorimetry differences in micronized and unmicronized nimesulide uptake processes in biomembrane models.

Nimesulide release from micronized and unmicronized drug particles was tested at pH 7.4 by measuring the transfer to dimyristoylphosphatidylcholine liposomes (multilamellar and unilamellar vesicles), chosen as a biomembrane model. The perturbing effect of increasing molar fractions of pure nimesulide on the thermotropic behaviour of dimyristoylphosphatidylcholine liposomes was investigated by differential scanning calorimetry. In order to study the drug dissolution process by its uptake into void liposomes, measurements were carried out on suspensions of blank liposomes added to weighed amounts of free powdered nimesulide (micronized and unmicronized). The amount of drug transferred was quantified by comparing the effect caused by the dissolved and released drug to that caused by the free drug that had been previously molecularly dissolved in the liposomes. The calorimetric results show that the dissolution rate depends on the nimesulide form (micronized or unmicronized), and that the transfer to the void liposomes is quicker when the drug is in a micronized form. The uptake was faster when unilamellar vesicles were used instead of multilamellar vesicles because of the greater lipid surface. The calorimetric technique could represent an alternative 'in vitro' method that can be applied to the study of the dissolution kinetics directly at the site of drug uptake, mimicking a biological system.

Flurbiprofen release from Eudragit RS and RL aqueous nanosuspensions: a kinetic study by DSC and dialysis experiments.

The present work investigated the release of Flurbiprofen (FLU) from Eudragit RS100 (RS) and Eudragit RL100 (RL) nanosuspensions to a biological model membrane consisting of Dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles (MLV). This release was compared with those observed from solid drug particles as well as with dialysis experiments. Nanosuspensions were prepared by a modification of Quasi-Emulsion Solvent Diffusion technique. Drug release was monitored by the Differential Scanning Calorimetry (DSC). FLU dispersed in MLV affects the transition temperature (T(m)) of DMPC liposomes, causing a shift towards lower values. The temperature shift is modulated by the drug fraction present in the aqueous lipid bilayer suspension. DSC was also performed, after increasing incubation periods at 37 degrees C, on suspensions of blank liposomes added to fixed amounts of unloaded and FLU-loaded nanosuspensions, as well as to powdered free drug. T(m) shifts, caused by the drug released from the polymeric system or by free-drug dissolution during incubation cycles, were compared with those caused by free drug increasing molar fractions dispersed directly in the membrane during their preparation. These results were compared with the drug release and were followed by a classical dialysis technique. Comparing the suitability of the 2 different techniques in order to follow the drug release as well as the differences between the 2 RL and RS polymer systems, it is possible to confirm the efficacy of DSC in studying the release from polymeric nanoparticulate systems compared with the "classical" release test by dialysis. The different rate of kinetic release could be due to void liposomes, which represent a better uptaking system than aqueous solution in dialysis experiments.

Assessment of nephrotoxicity of high-cumulative dose of liposomal amphotericin B in a pediatric patient who underwent allogeneic bone marrow transplantation.

We describe a 9-yr-old boy who received the highest cumulative dose so far reported of liposomal amphotericin B. The patient underwent an allogeneic bone marrow transplantation (BMT) for adrenoleucodystrophy, after a conditioning regimen with busulfan, thiothepa and cyclophosphamide. Rabbit antithymoglobulin, cyclosporin and prednisone were used as prophylaxis against graft vs. host disease (GVHD). Post-transplant Epstein-Bar-virus-related lymphoma was diagnosed on day +68 and was treated with donor-derived lymphocytes. The patient developed a severe form of GVHD, and a progressive worsening of his neurological status because of progression of his underlying disease. Death from septic shock occurred 23 months after BMT. During prolonged hospitalization, 19,750 mg of liposomal amphotericin B, about 1000 mg/kg, were given for prophylactic or empirical therapeutic purposes without significant nephrotoxicity. This case suggests that liposomal amphotericin B is safe and well-tolerated even if is administered for long periods and a cumulative dose fivefold greater than the nephrotoxic threshold of amphotericin B deoxycholate is achieved.

Safety and efficacy of caspofungin and liposomal amphotericin B, followed by voriconazole in young patients affected by refractory invasive mycosis.

OBJECTIVE: Data on the use of combination of liposomal amphotericin B and caspofungin followed by voriconazole, as maintenance or further rescue treatment, in 10 patients with invasive mycosis are reported. MATERIAL AND METHODS: The diagnoses were acute leukemia (7), myelodysplastic syndrome (1) and Hodgkin's lymphoma (1). All patients developed an invasive mycosis (proven, 3; probable, 6; and possible, 1) refractory to first-line antifungal treatment (liposomal amphotericin B in all patients except one who received fluconazole). RESULTS: Rescue therapy with a combination of caspofungin and liposomal amphotericin B was well tolerated, hypokalemia, and thrombophlebitis being the most common side-effects. Combination therapy was administered for a median of 17 d, range 6-40. Among the nine patients with proven or probable mycosis, one was not evaluated because of early death caused by massive hemoptysis whilst in the remaining eight patients, the response was classified as complete, stable and failure in four, three, and one patients, respectively. Complete response was also observed in patient with possible mycosis. Eight of nine patients received voriconazole for a median of 75 d, range 42-194. Voriconazole was well tolerated although some drug interactions were observed during treatment with methotrexate and digoxin. After a median follow-up of 125 d, nine of 10 patients are alive. Overall, a favorable response to antifungal treatment (including the case of possible mycosis) was obtained in eight of 10 patients. CONCLUSION: These data suggest that medical antifungal treatment may be intensified in severely ill patients without significantly compromising patient safety. The combination of synergistic antifungal drugs as well as their sequential use warrants further investigation by a larger randomized controlled study.