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Biomedical subjects

T York

Publications and source records attributed to T York.

12 recordsLinked to original sources
PubMed2000

Stromal cells regulate survival of B-lineage leukemic cells during chemotherapy.

Approximately 20% of B-lineage acute lymphoblastic leukemias are not cured by traditional chemotherapy. The possibility was examined that residual leukemic cells that potentially contribute to relapse are harbored in association with fibroblastic stromal cells in the bone marrow. Modulation of cytarabine (Ara-C) and etoposide (VP-16) efficacy by bone marrow stromal cells in vitro was investigated. Stromal cell coculture was shown to sustain the proliferation of B-lineage leukemic cells and to reduce leukemic cell apoptosis when exposed to Ara-C or VP-16. Direct contact with stromal cells was essential for the protection of leukemic cells during chemotherapy, whereas soluble factors had negligible effect. Specifically, signaling mediated through interaction with the stromal cell adhesion molecule VCAM-1 was required to maintain the maximum viability of leukemic cells during Ara-C and VP-16 exposure. In contrast, the interaction of leukemic cells with fibronectin did not confer significant resistance to either chemotherapeutic agent. These observations suggest a role for the bone marrow microenvironment in modulating the response of B-lineage leukemic cells to Ara-C or VP-16, and they indicate specific molecular interactions that may be important in determining the sensitivity of leukemic cells to treatment. (Blood. 2000;96:1926-1932)

Antineoplastic Agents↗
PubMedDate not supplied

Venous valvular assessment after retrograde catheterization.

PURPOSE: To determine whether retrograde passage of a coaxial infusion system (Mewissen-Katzen catheter and guide wire) into extremity veins with valves causes damage. MATERIALS AND METHODS: Retrograde common femoral vein puncture and passage of an infusion wire-catheter system through the superficial femoral and popliteal veins of one leg were performed in five anesthetized pigs. Heparinized saline was then infused via the catheter and wire for approximately 8 hours. The pigs were then killed, and the femoropopliteal veins were removed from both legs of each pig and examined by a pathologist. The noncatheterized leg veins served as a control in each animal. RESULTS: Valvular damage occurred in one of five pigs. This may have resulted from leg movement during catheter passage in this animal. CONCLUSION: Retrograde passage of a catheter-guide-wire infusion system caused minimal to no damage to the venous valves of pigs. This suggests that human venous valves may be spared injury during catheter-directed venous thrombolysis. Further study of catheter manipulation in a model of deep venous thrombosis is needed.

Animals↗