The development of an active drug delivery system is an attractive approach to increase the targetability of anticancer agents. In the present study, we examined the efficiency of systemic chemotherapy with small magnetic liposomes containing doxorubicin (magnetic DOX liposomes) and an externally applied electromagnetic force in osteosarcoma-bearing hamsters. Syrian male hamsters inoculated with osteosarcoma, OS515, in the limb were studied 7 days after inoculation. The efficiency of this system was evaluated by measuring the tissue distribution and tumor-suppressing effects of DOX on primary tumor growth and lung metastases. A DC dipole electromagnet was used, and the hamster's tumor-bearing limb was placed between 2 poles after the i.v. administration of liposomes. The dose of DOX and the magnetic field strength were fixed at 5 mg/kg and 0.4 T, respectively. Administration of magnetic DOX liposomes followed by 60 min application of magnetic field produced a 3- to 4-fold higher maximum DOX concentration in the tumor. This newly designed systemic chemotherapy significantly suppressed primary tumor growth for at least 2 weeks, though other DOX treatments also suppressed compared to control. Histologic examination confirmed a greater antitumor effect of this systemic chemotherapy compared to standard methods. In addition, this approach significantly suppressed lung metastases measured at 3 weeks posttreatment. These results suggest that this systemic chemotherapy can effectively reduce primary tumor growth and suppress lung metastasis due to increased targeting of DOX. Such targeted drug delivery for anticancer agents would provide clinical advantages compared to current methods.

Articular cartilage has very limited potential to spontaneously heal, because it lacks vessels and is isolated from systemic regulation. Although there have been many attempts to treat articular cartilage defects, such as drilling, microfracture techniques, soft tissue grafts or osteochondral grafts, no treatment has managed to repair the defects with long-lasting hyaline cartilage. Recently, a regenerative medicine using a tissue engineering technique for cartilage repair has been given much attention in the orthopedic field. In 1994, Brittberg et al. introduced a new cell technology in which chondrocytes expanded in monolayer culture were transplanted into the cartilage defect of the knee. As a second generation of chondrocyte transplantation, since 1996 we have been performing transplantation of tissue-engineered cartilage made ex vivo for the treatment of osteochondral defects of the joints. This signifies a concept shift from cell transplantation to tissue transplantation made ex vivo using tissue engineering techniques. We have reported good clinical results with this surgical treatment. However, extensive basic research is vital to achieve better clinical results with this tissue engineering technique. This article describes our recent research using a minimally invasive tissue engineering technique to promote cartilage regeneration.

In major-nerve schwannomas, the Tinel-like sign, split-fat sign, entering and exiting nerve, and low-signal margin are commonly observed and useful for diagnosis. In intramuscular schwannomas, these characteristic findings are less common, which makes diagnosis difficult.