Paracrine effects of living human bone particles on the osteogenic differentiation of mesenchymal stem cells

Bone autografting remains the clinical model of choice for resolving problematic fractures. The precise mechanisms through which the autograft promotes bone healing are unknown. The present study examined the hypothesis that cells within the autograft secrete osteogenic factors promoting the differentiation of mesenchymal stem cells (MSCs) into osteoblasts. Particles of human bone (“chips”) were recovered at the time of joint replacement surgery and placed in culture. Then, conditioned media were added to cultures of human, adipose-derived MSCs under both basal and osteogenic conditions. Contrary to expectation, medium conditioned by bone chips reduced the expression of alkaline phosphatase and strongly inhibited mineral deposition by MSCs cultured in osteogenic medium. Real time PCR revealed the inhibition of collagen type I alpha 1 chain (Col1A1) and osteopontin (OPN) expression. These data indicated that the factors secreted by bone chips inhibited the osteogenic differentiation of MSCs. However, in late cultures, bone morphogenetic protein-2 (BMP-2) expression was stimulated, suggesting the possibility of a delayed, secondary osteogenic effect

Donor cell leukemia in a patient developing 11 months after an allogeneic bone marrow transplantation for chronic myeloid leukemia

A 38‐year‐old female with chronic myeloid leukemia underwent an allogeneic bone marrow transplantation from her full‐matched brother. Eleven months later, she readmitted with an acute leukemia that was shown to be of donor origin. The patient never achieved a remission even after chemotherapies with cytarabine and mitoxantrone, donor lymphocyte infusion, and second allogeneic peripheral blood stem cell transplantation. Donor cell leukemia (DCL) is sometimes misdiagnosed as relapse by clinicians and the real incidence may be higher than expected. Cytogenetic and molecular techniques may be helpful to clarify the issue of the leukemia. The current case is another case of DCL reported in the literature after an allogeneic transplant for a kind of leukemia. Am. J. Hematol. 81:370–373, 200

Haemangioma originating from a tendon sheath as an unusual cause of trigger wrist: Case report

Haemangioma localised in the wrist originating from the sheath of the fifth deep flexor tendon and obstructing the movement of the tendon through the carpal tunnel as an unusual cause of trigger wrist is presented. Tumoural masses around the wrist can cause triggering by obstructing the movement of tendons through the carpal tunnel and the clinician should consider other causes of triggering for surgical treatment.The Yeditepe University Open Access System is a compendium of indexed publications. Copyright and usage rights may be held by publishers and/or authors. The collection was established for the scientific publications prepared by Yeditepe University academicians and is to be found in the institutional archive