Characterization of Novel Paclitaxel Nanoparticles Prepared by Laser Irradiation.

The antitumor drug paclitaxel has low water solubility, and its bioavailability is limited by the dissolution rate. To overcome this low water solubility, the currently marketed drug, Taxol, is formulated in a vehicle including Cremophor EL and ethanol mixture (1/1, v/v). However, Cremophor EL has been shown to have serious adverse side effects, such as hypersensitivity reactions and neurotoxicity. Improving the solubility of paclitaxel makes it possible to reduce side effects and enhance drug efficacy during antitumor therapy. One way to improve the solubility of poorly soluble drugs is to decrease their particle size to the nano-range to increase the surface area and dissolution rate. In the present study, we aimed to develop a new method for paclitaxel nanoparticle production. Polymeric nanoparticles of paclitaxel were prepared by laser irradiation at 1064 nm, which is the wavelength in the near-IR region. The prepared nanoparticles had a mean size of 57.9 nm and were spherical in shape. X-ray powder diffraction analysis showed that paclitaxel in the nanoparticles was in an amorphous state. These results demonstrate that the preparation of nanoparticles by laser irradiation is effective in improving the solubility of paclitaxel. Furthermore, the nanoparticles had an equivalent efficacy to Taxol in cell growth inhibition against breast cancer MCF-7 cells and drug efficacy in MCF-7 tumor-bearing mice as determined using positron emission tomography. Our method for preparing paclitaxel nanoparticles may be more effective in treating tumors with fewer adverse side effects than conventional Taxol.

Preparation of polymeric nanoparticles of cyclosporin A using infrared pulsed laser.

Nanoparticle formation of poorly water-soluble drugs is a means of providing much benefit for improving solubility and bioavailability. We showed that laser irradiation of drugs can be a novel tool for dispersing drug nanoparticles in water. Using our method, we were able to produce nanoparticles containing immunosuppressant drug, cyclosporin A, which shows poor solubility toward water, with high levels of the drug using polyvinyl pyrrolidone and sodium dodecyl sulfate as stabilizing agents. The absence of degradation products was confirmed and the loss of pharmaceutical activity with an inhibitory effect on the interleukin-2 production of Jurkat T cells did not occur. Cyclosporin A nanoparticles showed a spherical shape and their particle size was distributed uniformly around 200 nm. Powder X-ray diffraction analysis suggested that cyclosporin A in the nanoparticles was in an amorphous state. In the measurement of solubility rate, the nanoparticle formulation showed a higher rate than that which had not been processed. At present, although this laser irradiation technology has low productivity, it is expected as a new technology for drug nanoparticle manufacturing together with the development of a new laser device.

Baseline data of Shizuoka area in the Japan Multi-Institutional Collaborative Cohort Study (J-MICC Study).

The Japan Multi-Institutional Collaborative Cohort (J-MICC) Study launched in 2005 by ten research groups throughout Japan aimed to examine gene-environment interactions in lifestyle-related diseases, especially cancers. This paper describes one component of the J-MICC Study, named Shizuoka Study, in which visitors aged 35 to 69 years to the Seirei Preventive Health Care Center in Hamamatsu were enrolled. Among 13,740 visitors matching eligibility criteria, 5,040 persons (36.7%) were enrolled from January 2006 to December 2007. Their lifestyle, disease history, and family history were surveyed using a self-administrated questionnaire. Blood and urine were collected from the participants. By the end of December 2008, 8 withdrawers and 1 ineligible participant had been removed, leaving 5,031 participants (3,419 males and 1,612 females) as the baseline dataset. Current smokers were 23.3% among males, and 4.4% among females, and those who drank once or more per month were 76.9% and 38.6%, respectively. Those with a cancer history were 3.0% for males and 3.8% for females. Measurements out of a normal range in males and females were 11.3% and 4.0% for diastolic blood pressure > or = 90 mmHg, 11.0% and 7.6% for systolic blood pressure > or = 140 mmHg, 5.9% and 1.7% for fasting blood glucose > or = 126 mg/dl, respectively. Collected information and specimens will be cooperatively used to examine the associations of biomarkers with lifestyle, genotypes, and their combinations, as well as for a part of the J-MICC Study.

Short-step and scalable synthesis of (+/-)-cytoxazone.

A five-step and scalable synthesis of racemic cytoxazone, a novel cytokine modulator, was accomplished in a total yield of 51% from p-methoxycinnamyl alcohol without any protective groups. The keystep was the new one-pot azidohydroxylation procedure by the combined use of NaN3-H2O2-CH3CN. The epoxidation of an olefin by means of an in situ-formed iminohydroperoxide worked well, accompanied by the concomitant regioselective ring opening reaction of the resulting highly reactive epoxide with an azide ion.

Development of a nerve scaffold using a tendon chitosan tube.

Bridge grafting (15 mm) into the sciatic nerve of SD rats was carried out using tendon chitosan tubes having either a circular or triangular cross-section, as well as triangular tubes combined with laminin, CDPGYIGSR, or CSRARKQAASIKVAVSAD (n = 15 in each group). As a control, isografting (15 mm) was carried out in the SD rats (n = 7). Specimens were taken after 1, 2, 4, 6, and 8 weeks for histology, and nerve regeneration was evaluated electro-physiologically and histologically after 12 weeks. The mechanical strength of triangular tubes was found to be higher than circular tubes, and the inner volume of a triangular tube tends to be larger than in circular tubes. Nerve tissue regeneration along the tube wall was found in both the laminin and laminin peptide groups. According to the result of percentage neural tissue in relation to evoked action potentials, the consecutive treatments of YIGSR and IKVAV was found to match the effectiveness of intact laminin.

Hydroxyapatite-coated tendon chitosan tubes with adsorbed laminin peptides facilitate nerve regeneration in vivo.

On the inner surface of tendon chitosan tubes having a triangular shape and a hydroxyapatite coating (t-chitosan/HAp tube), laminin-1 and laminin peptides (YIGSR, IKVAV) have been adsorbed in order to develop nerve growth conduits. The mechanical property, biocompatibility and efficacy of these tubes for nerve regeneration were examined. Step-1: bridge grafting (15 mm) into the sciatic nerve of Sprague-Dawley (SD) rats was carried out using either t-chitosan or t-chitosan/HAp tubes having either a circular or triangular cross section (N=12 in each group). Specimens were taken after 2-, 4-, 6- and 8-week post-implantation (N=3 in each group) for histology determinations. Step-2: t-chitosan/HAp tubes having a triangular cross section with adsorbed laminin-1, CDPGYIGSR or CSRARKQAASIKVAVSAD, as well as control tubes without pre-adsorption were used for implantation (N=18 in each group). Isografting was also carried out (N=6). Histological evaluation was carried out similarly as in Step-1. Furthermore, evoked muscle and sensory nerve action potentials were recorded, and the percentage of myelinated axon area measured at 10 mm distance of the distal anastomosed site in the experimental, control and isograft groups after 12 weeks (N=6 in each group). The results of histological findings, as well as mechanical properties, suggest that a triangular tube shape with a HAp coating benefits nerve regeneration. The effect of laminin peptides (YIGSR, followed by IKVAV) to enhance the growth of regenerating axons has been found comparable with intact laminin-1. Although histological regeneration in both the YIGSR- and laminin-1-treated t-chitosan/HAp tubes matches the isografts, the functional recovery is however delayed.

Tendon chitosan tubes covalently coupled with synthesized laminin peptides facilitate nerve regeneration in vivo.

We have developed tendon chitosan tubes having the ability to bind peptides covalently, and the effectiveness of laminin peptides coupled to these tubular wall on nerve regeneration was examined in vivo. Bridge graft implantation (15 mm) into the sciatic nerve of SD rats was carried out using chitosan tubes having a triangular cross section containing either covalently bound intact laminin or the laminin peptides CDPGYIGSR or CSRARKQAASIKVAVSAD or being nontreated (N = 20 in each group). As a control, isografting (N = 5) was carried out. Three rats in each experimental group were sacrificed for histology observations after 1, 2, 4, 6, and 8 weeks. The total area of regenerating tissue in the tube and the length of the area where regenerating tissue attached to the inner surface of the tube were measured. In five rats from each experimental and control group, the latency quotient between the implanted and the nontreated site was determined 12 weeks after implantation. Furthermore, the percentage of myelinated axon area was measured at a 10-mm distance from the distal anastomosed site. Histological findings suggest that the immobilized laminin, confirmed by immunostaining as long as 12 weeks postoperatively, as well as laminin oligopeptides may effectively assist nerve tissue extension. According to statistical analysis of the percentage neural tissue found in relation to evoked action potentials, the sequential treatments with YIGSR first followed by IKVAV matched the effectiveness of intact laminin in enhancing nerve regeneration. However, when compared with that after isografting, the enhancement of regenerated axon growth was less sufficient.

The chitosan prepared from crab tendons: II. The chitosan/apatite composites and their application to nerve regeneration.

The chitosan tubes derived from crab tendons form a hollow tube structure, which is useful for nerve regeneration. However, in order to use the chitosan tubes effectively for nerve regeneration, there remain two problems to be solved. First, the mechanical strength of the tubes is quite high along the longitudinal axis, but is somewhat low for a pressure from side. Second, the chitosan tube walls swell to reduce the inner space of the tubes in vivo. These two problems limit the clinical use of the chitosan tubes. In this study, to solve the problems, apatite was made to react with the chitosan tubes to enhance the mechanical strength of the tube walls. Transmission electron microscopy showed that apatite crystals were formed in the walls of the chitosan tubes. The c-axis of the crystals aligned well in parallel with chitosan molecules. These results indicate that the apatite crystals grow in the tubes starting from the nucleation sites of the chitosan molecules, probably by forming complexes with amino groups of chitosan and calcium ions. Further, the tubes were thermally annealed at 120 degrees C to prevent from swelling, and simultaneously formed into a triangular shape to enhance the stabilization of the tube structure. By these treatments, the hollow tubes could keep their shape even in vivo after implantation. Animal tests using SD rats further showed that the chitosan tubes effectively induced the regeneration of nerve tissue, and were gradually degraded and absorbed in vivo.

The chitosan prepared from crab tendon I: the characterization and the mechanical properties.

Crystalline chitosan was prepared from crab tendon consisting mainly of chitin, including various proteins and calcium phosphates. The crab tendon has high mechanical properties due to its aligned molecular structure. Crab tendon components, i.e. proteins and calcium phosphates, were removed by deacetyl treatment using 50wt% NaOH aqueous solution at 100 degrees C, and a subsequent ethanol treatment. As judged from microscopic observations using an optical polarizer, the treated chitosan remained intact regarding its aligned molecular structure, and had a high tensile strength of 67.9+/-11.4MPa. The tensile strength was further enhanced to 235+/-30MPa by a thermal treatment at 120 degrees C, corresponding to the formation of the intermolecular hydrogen bonds.