Darko Bosnakovski

Publications (23)112.57 Total impact

• Source

  Available from: hokudai.ac.jp

  Article: Effects of ascorbic acid on proliferation and biological properties of bovine chondrocytes in alginate beads.

  Gonhyung Kim, Masahiro Okumura, Darko Bosnakovski, Taketo Ishiguro, Chun-Ho Park, Tsuyoshi Kadosawa, Toru Fujinaga
  [show abstract] [hide abstract]
  ABSTRACT: Bovine chondrocytes were cultured in monolayers and alginate beads with or without ascorbic acid (Asc) for 16 days. Cell proliferation was examined every 4 days by staining with Hoechst 33258 dye. The gene expression of aggrecan, and collagen type I and II was analyzed at 16 days by reverse transcription and polymerase chain reaction. Cell morphology and the production of extracellular matrix (ECM) were evaluated by cytochemical, immunocytochemical and electron microscopical methods. Cells were continuously cultured in alginate beads with Asc for 2 months, and the cell morphology and ECM were examined. The proliferation of chondrocytes was significantly stimulated with Asc in both monolayers and alginate beads at 16 days. Expression of the collagen type I gene in both cultures was increased, and that of the collagen type II gene in alginate beads was decreased, by Asc. There were no significant cytochemical and immunocytochemical differences between the cultures in alginate beads with or without Asc at 16 days. In alginate beads cultured with Asc for 2 months, proliferating cells were observed mainly at the periphery of the beads, and glycosaminoglycan and collagen type II were found around the cells. These results suggest that Asc stimulated the proliferation of chondrocytes and maintained the chondrogenic properties of the cells in an alginate beads culture.
  The Japanese journal of veterinary research 09/2003; 51(2):83-94. · 0.46 Impact Factor
• Article: Relationship of disease progression and plasma histamine concentrations in 11 dogs with mast cell tumors.

  Taketo Ishiguro, Tsuyoshi Kadosawa, Satoshi Takagi, Gonhyung Kim, Tomohiro Ohsaki, Darko Bosnakovski, Masahiro Okumura, Toru Fujinaga
  [show abstract] [hide abstract]
  ABSTRACT: Plasma histamine concentrations (PHCs) were measured serially over 9 months or until death in 11 dogs with mast cell tumors (MCTs). Eight dogs had grossly visible disease and the other 3 dogs had microscopic disease. Initial PHCs in the dogs with gross disease were significantly higher than PHCs in healthy dogs (median, 0.73 ng/mL and 0.19 ng/mL respectively; P < .009), whereas initial PHCs in dogs with microscopic disease showed no difference from controls. Seven dogs subsequently had progressive increases in PHC, and developed hyperhistaminemia (median, 14.0 ng/mL; range, 5.11-30.1 ng/nL). These 7 dogs died from MCTs, and 1 had general weakness with rapid lysis of a large tumor burden after radiation therapy. PHCs of the other 4 dogs were less than 1 ng/mL during the study. These 4 dogs were still alive with adequate control of the tumor at the conclusion of the study. Four of the 11 dogs initially had gastrointestinal (G1) signs, which abated soon after administration of histamine-2 (H-2) blockers. No significant difference was found between PHCs in dogs with GI signs and those without GI signs (median, 0.86 ng/mL and 0.35 ng/mL. respectively). Thereafter, 7 dogs had serious GI complications for which H-2 blocker therapy was ineffective. PHCs in these 7 dogs were extremely high (median, 12.2 ng/mL; range, 3.42-30.1 ng/nL). Results of this study demonsrated that PHC was one factor related to disease progression, and indicated that marked hyperhistaminemia was associated with the GI signs refractory to H-2 blocker therapy in dogs with MCTs.
  Journal of Veterinary Internal Medicine 17(2):194-8. · 1.99 Impact Factor
• Article: Engraftment of mesenchymal stem cells into dystrophin-deficient mice is not accompanied by functional recovery

  Eun Ji Gang, Radbod Darabi, Darko Bosnakovski, Zhaohui Xu, Kristine E. Kamm, Michael Kyba, Rita C.R. Perlingeiro
  [show abstract] [hide abstract]
  ABSTRACT: Mesenchymal stem cell preparations have been proposed for muscle regeneration in musculoskeletal disorders. Although MSCs have great in vitro expansion potential and possess the ability to differentiate into several mesenchymal lineages, myogenesis has proven to be much more difficult to induce. We have recently demonstrated that Pax3, the master regulator of the embryonic myogenic program, enables the in vitro differentiation of a murine mesenchymal stem cell line (MSCB9-Pax3) into myogenic progenitors. Here we show that injection of these cells into cardiotoxin-injured muscles of immunodeficient mice leads to the development of muscle tumors, resembling rhabdomyosarcomas. We then extended these studies to primary human mesenchymal stem cells (hMSCs) isolated from bone marrow. Upon genetic modification with a lentiviral vector encoding PAX3, hMSCs activated the myogenic program as demonstrated by expression of myogenic regulatory factors. Upon transplantation, the PAX3-modified MSCs did not generate rhabdomyosarcomas but rather, resulted in donor-derived myofibers. These were found at higher frequency in PAX3-transduced hMSCs than in mock-transduced MSCs. Nonetheless, neither engraftment of PAX3-modified or unmodified MSCs resulted in improved contractility. Thus these findings suggest that limitations remain to be overcome before MSC preparations result in effective treatment for muscular dystrophies.
  Experimental Cell Research.