Recent Ⅳ-drug users with chronic hepatitis C can be efficiently treated with daily high dose induction therapy using consensus interferon:An open-label pilot study

INTRODUCTION Under physiological conditions, interferon-α (IFN-α) is a key cytokine produced by virtually all cells in the mammalian organism in response to a variety of bacterial and viral stimuli. In response to viral infection, IFN-α produced by the infected target cells induces a number of cellular genes involved in inhibition of viral replication. In addition, IFN-α is secreted by stimulated NK-cells and T-cells and exerts a multitude of immune stimulatory effects of innate a…     

Crystal Growth in Poly(L‐lactide) Thin Film Revealed by in situ Atomic Force Microscopy

Direct visualization of crystal growth in poly(L ‐lactide) thin films was carried out by using a temperature‐controlled atomic force microscopy (AFM). At the initial stage of crystallization, edge‐on lamellar crystals have nucleated and elongated. Subsequently, the edge‐on lamellar crystals showed S‐shaped morphology and changed their orientation from edge‐on manner to flat‐on one. The curvature of edge‐on lamellar crystal has been discussed in terms of inclination and distortion of polymer chains in the crystal. In addition, mechanism on the formation of flat‐on crystal from edge‐on lamellae was proposed as derivative growth on the basis of in situ AFM observation of crystal growth and enzymatic degradation.

     

Surface Modification of Poly(lactide-co-glycolide) Nanospheres by Biodegradable Poly(lactide)-Poly(ethylene glycol) Copolymers

The modification of surface properties of biodegradable poly(lactide-co-glycolide) (PLGA) and model polystyrene nanospheres by poly(lactide)-poly(ethlene glycol) (PLA:PEG) copolymers has been assessed using a range of in vitro characterization methods followed by in vivo studies of the nanospheres biodistribution after intravenous injection into rats. Coating polymers with PLA:PEG ratio of 2:5 and 3:4 (PEG chains of 5000 and 2000 Da, respectively) were studied. The results reveal the formation of a PLA: PEG coating layer on the particle surface resulting in an increase in the surface hydrophilicity and decrease in the surface charge of the nanospheres. The effects of addition of electrolyte and changes in pH on stability of the nanosphere dispersions confirm that uncoated particles are electrostatically stabilized, while in the presence of the copolymers, steric repulsions are responsible for the stability. The PLA:PEG coating also prevented albumin adsorption onto the colloid surface. The evidence that this effect was observed for the PLA:PEG 3:4 coated nanospheres may indicate that a poly(ethylene glycol) chain of 2000 Da can provide an effective repulsive barrier to albumin adsorption. The in vivo results reveal that coating of PLGA nanospheres with PLA:PEG copolymers can alter the biodistribution in comparison to uncoated PLGA nanospheres. Coating of the model polystyrene nanospheres with PLA:PEG copolymers resulted in an initial high circulation level, but after 3 hours the organ deposition data showed values similar to uncoated polystyrene spheres. The difference in the biological behaviour of coated PLGA and polystyrene nanospheres may suggest a different stability of the adsorbed layers on these two systems. A similar biodistribution pattern of PLA:PEG 3:4 to PEG 2:5 coated particles may indicate that poly(ethylene glycol) chains in the range of 2000 to 5000 can produce a comparable effect on in vivo behaviour.     

Study and development of encapsulated forms of 4, 5′, 8‐Trimethylpsoralen for topical drug delivery

Trimethylpsoralen (TMP) is often used to treat skin diseases (i.e., psoriasis, vitiligo, etc.). This drug permeates moderately the skin barrier. In the present study, we investigated the effect of formulation on the improvement of TMP skin bioavailability. Three formulations were performed. Each form (liposomes, nanospheres, and EtOH solution) contained 0.05% of TMP. For each preparation, the quantity deposited on the skin surface was 250 µg (Q₀). The TMP percutaneous penetration through ex‐vivo human skin was processed by Franz^® cells (n=4) using a human albumin solution (1.4% w/v) as receiver medium. The percentages of the extracted TMP that permeated through the skin and that were retained in the skin over 24 h, were calculated with respect to Q₀. The values obtained were reported, respectively, as follows: EtOH solution (1.33 vs. 0.08%), liposomes (0.93 vs. 0.93%), and PLG‐nanospheres (0.79 vs. 3.01%). So, considering the correlation between the cumulated amounts of TMP permeated through the skin and the TMP stocked in the skin, the nanosphere form showed the higher quantity of TMP accumulated in the skin structures. On the other hand, the maximum value of the flux (ng/cm²/h) in the steady state of TMP incorporated in each formulation was at 6 h for all formulations: 173.5±1.06 (EtOH solution) > 120.4±1.06 (liposomes) > 93.82±0.88 (PLG‐nanospheres). These results indicate that the controlled release of TMP by incorporation in PLG‐nanospheres may increase drug content in the skin, while maintaining a minimal percutaneous absorption. Finally, this work shows that the PLG‐nanospheres could constitute a promising approach for controlling TMP release in order to maintain its topical activity. Drug Dev. Res. 61:86–94, 2004. © 2004 Wiley‐Liss, Inc.     

In vivo toxicological evaluation of polymeric nanocapsules after intradermal administration

Polymeric nanocarriers have shown great promise as delivery systems. An alternative strategy has been to explore new delivery routes, such as intradermal (i.d.), that can be used for vaccines and patch-based drug delivery. Despite their many advantages, there are few toxicity studies, especially in vivo. We report a safety assessment of biodegradable poly(ɛ-caprolactone) lipid-core nanocapsules (LNC) with a mean size of 245 ± 10 nm following single and repeated intradermal injections to Wistar rats. Suspensions were prepared by interfacial deposition of polymer. The animals (n = 6/group) received a single-dose of saline solution (1.2 ml/kg) or LNC (7.2 × 10¹² LNC/kg), or repeated-doses of two controls, saline solution or Tween 80 (0.9 ml/kg), or three different concentrations of LNC (1.8, 3.6, and 5.4 × 10¹² LNC/kg) for 28 consecutive days. Clinical and physiological signs and mortality were observed. Samples of urine, blood, and tissue were used to perform toxicological evaluation. There were no clinical signs of toxicity or mortality, but there was a slight decrease in the relative body weights in the Tween 80–treated group (p < 0.01) after repeated administration. No histopathological alterations were observed in tissues or significant changes in blood and urinary biomarkers for tissue damage. Mild alterations in white blood cells count with increases in granulocytes in the Tween-80 group (p < 0.05) were found. Genotoxicity was evaluated through the comet assay, and no statistical difference was observed among the groups. Therefore, we conclude that, under the conditions of these experiments, biodegradable LNC did not present appreciable toxicity after 28 consecutive days of intradermal administration and is promising for its future application in vaccines and patch-based devices for enhancing the delivery of drugs.     

Reconstruction of hepatic stellate cell‐incorporated liver capillary structures in small hepatocyte tri‐culture using microporous membranes

In liver sinusoids, hepatic stellate cells (HSCs) locate the outer surface of microvessels to form a functional unit with endothelia and hepatocytes. To reconstruct functional liver tissue in vitro, formation of the HSC‐incorporated sinusoidal structure is essential. We previously demonstrated capillary formation of endothelial cells (ECs) in tri‐culture, where a polyethylene terephthalate (PET) microporous membrane was intercalated between the ECs and hepatic organoids composed of small hepatocytes (SHs), i.e. hepatic progenitor cells, and HSCs. However, the high thickness and low porosity of the membranes limited heterotypic cell–cell interactions, which are essential to form HSC–EC hybrid structures. Here, we focused on the effective use of the thin and highly porous poly( d , l ‐lactide‐co‐glycolide) (PLGA) microporous membranes in SH–HSC–EC tri‐culture to reconstruct the HSC‐incorporated liver capillary structures in vitro. First, the formation of EC capillary‐like structures was induced on Matrigel‐coated PLGA microporous membranes. Next, the membranes were stacked on hepatic organoids composed of small SHs and HSCs. When the pore size and porosity of the membranes were optimized, HSCs selectively migrated to the EC capillary‐like structures. This process was mediated in part by platelet‐derived growth factor (PDGF) signalling. In addition, the HSCs were located along the outer surface of the EC capillary‐like structures with their long cytoplasmic processes. In the HSC‐incorporated capillary tissues, SHs acquired high levels of differentiated functions, compared to those without ECs. This model will provide a basis for the construction of functional, thick, vascularized liver tissues in vitro. Copyright © 2012 John Wiley & Sons, Ltd.     

Biofabrication of a PLGA–TCP‐based porous bioactive bone substitute with sustained release of icaritin

A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l ‐lactide‐co‐glycolide)–tricalcium phosphate (PLGA–TCP)‐based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin‐releasing PLGA–TCP‐based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro‐computed tomography (micro‐CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA–TCP scaffold was quantified by high‐performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA–TCP–icaritin composite scaffold was porous, with interconnected macro‐ (about 480 µm) and micropores (2–15 µm). The mechanical properties of the PLGA–TCP–icaritin scaffold were comparable with those of the pure PLGA–TCP scaffold, yet was spinning direction‐dependent. Icaritin content was detected in the medium and increased with time. The PLGA–TCP–icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA–TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic applications. Copyright © 2012 John Wiley & Sons, Ltd.     

Physiological features of Halomonas lionensis sp. nov., a novel bacterium isolated from a Mediterranean Sea sediment

A novel halophilic bacterium, strain RHS90^T, was isolated from marine sediments from the Gulf of Lions, in the Mediterranean Sea. Its metabolic and physiological characteristics were examined under various cultural conditions, including exposure to stressful ones (oligotrophy, high pressure and high concentrations of metals). Based on phylogenetic analysis of the 16S rRNA gene, the strain was found to belong to the genus Halomonas in the class Gammaproteobacteria. Its closest relatives are Halomonas axialensis and Halomonas meridiana (98% similarity). DNA–DNA hybridizations indicated that the novel isolate is genotypically distinct from these species. The DNA G + C content of the strain is 54.4 mol%. The main fatty acids (C_18:1 ω7c, 2-OH iso-C_15:0, C_16:0 and/or C_19:0 cyclo ω8c), main polar lipids (diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified phosphoglycolipid) and major respiratory quinone (ubiquinone Q9) were determined. The novel isolate is heterotrophic, mesophilic, euryhaline (growth optimum ranging from 2 to 8% w/v NaCl) and is able to grow under stressful conditions. The strain accumulates poly-β-hydroxyalkanoates granules and compatible solutes. Based on genotypic, chemotaxonomic and phenotypic distinctiveness, this isolate is likely to represent a novel species, for which the name Halomonas lionensis is proposed. The type strain of H. lionensis is RHS90^T (DSM 25632^T = CIP 110370^T = UBOCC 3186^T).     

Coexisting Straight,Radial, and Banded Lamellae on the Six Corners of Hexagon‐Shaped Spherulites in Poly(l‐Lactide)

A novel six‐petal spherulite morphology composed of a combination of a central hexagonal core, hexagon‐shaped ring bands, and six fibrous stalks is discovered in a low‐molecular‐weight poly(l ‐lactide acid) (LM_w‐PLLA) that is melt crystallized at a specific T_c = 110 °C and confined in thin films. The structures are analyzed by using polarized optical microscopy (POM) and atomic force microscopy (AFM). Discrete lamellae, consisting of sequenced wide and small lamellae, all in flat‐on orientation with periodically up‐and‐down topology, are packed in a ring‐banded alignment, while continuous lamellae in flat‐on, tilted, or edge‐on orientations are arranged in the fibrous region. On the six corners of a symmetric hexagon‐banded spherulite, the radial fibrous lamellae overlap with ring‐band lamellae to show a mixed combination of ring‐banded and fibrous patterns. The formation of coexisting ring‐banded and fibrous patterns in a mixed morphology is associated with the lamellar packing and orientation. The radial fibrous lamellae at the six corners favorably occur in the growth fronts, which are closer to the reservoir of materials of diffusing species. Superimposed on the radial lamellae, hexagon‐shaped ring bands repeat themselves on the outskirts of the central hexagon nuclei. The geometry of the initial crystal is believed to be the influencing factors in final spherulite patterns.

     

Characterization of poly-4-hydroxybutyrate mesh for hernia repair applications

Background

Phasix mesh is a fully resorbable implant for soft tissue reconstruction made from knitted poly-4-hydroxybutyrate monofilament fibers. The objectives of this study were to characterize the in vitro and in vivo mechanical and resorption properties of Phasix mesh over time, and to assess the functional performance in a porcine model of abdominal hernia repair.

Materials and methods

We evaluated accelerated in vitro degradation of Phasix mesh in 3 mol/L HCl through 120 h incubation. We also evaluated functional performance after repair of a surgically created abdominal hernia defect in a porcine model through 72 wk. Mechanical and molecular weight (MW) properties were fully characterized in both studies over time.

Results

Phasix mesh demonstrated a significant reduction in mechanical strength and MW over 120 h in the accelerated degradation in vitro test. In vivo, the Phasix mesh repair demonstrated 80%, 65%, 58%, 37%, and 18% greater strength, compared with native abdominal wall at 8, 16, 32, and 48 wk post-implantation, respectively, and comparable repair strength at 72 wk post-implantation despite a significant reduction in mesh MW over time.

Conclusions

Both in vitro and in vivo data suggest that Phasix mesh provides a durable scaffold for mechanical reinforcement of soft tissue. Furthermore, a Phasix mesh surgical defect repair in a large animal model demonstrated successful transfer of load bearing from the mesh to the repaired abdominal wall, thereby successfully returning the mechanical properties of repaired host tissue to its native state over an extended time period.