Biomedical subjects
Publications and source records attributed to J Aronson.
Aptamers targeting NF-kappaB containing thymidine 3'-O-phosphorodithioates in selected positions of an oligonucleotide duplex were synthesized. Binding affinities to NF-kappaB varied with the number and positions of the dithioate backbone substitutions. One of the aptamers showed specific binding to a single NF-kappaB dimer in cell culture extracts.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
To assess the potential of using distraction osteogenesis to reconstruct bone deficient limbs after limb salvage for musculoskeletal sarcomas, the authors examined the effect of methotrexate on distraction osteogenesis in a rabbit tibial lengthening model. Eighteen rabbits underwent tibial corticotomy and application of a ring external fixator. Rabbits were assigned randomly to one of two groups in which either methotrexate (n = 12) or placebo (n = 6) was administered during a 21-day distraction period. Serum methotrexate levels and complete blood cell counts were monitored during distraction, and radiographs of the tibia were obtained weekly. Half of the animals from each group were sacrificed at the end of distraction, and the remaining animals were sacrificed after 6 weeks of neutral fixation when bone normally bridges the gap. Using methotrexate at serum concentrations similar to those used clinically for the treatment of human osteosarcomas, the authors were unable to show significant radiographic, histologic, or chemical differences in the effect of this antineoplastic drug on distraction osteogenesis in the rabbit model.
BACKGROUND AND OBJECTIVES: This article describes the process used by the University of Wisconsin-Madison Family Practice Residency Program to establish its first rural training track (RTT) in Baraboo, Wis. The process includes 1) establishing a core planning group to develop rural site selection criteria with specifications on distance traveled, faculty composition, teaching commitment, rural hospital capabilities, and availability of subspecialty teaching, 2) involvement of the state Area Health Education Center, 3) budget planning, 4) telecommunications plans, including e-mail, library search, and Internet connectivity, 5) creation of a residency curriculum in collaboration with the rural site's faculty and staff, 6) preparing an accreditation document to submit to the Residency Review Committee, and 7) faculty development programs for rural faculty. The program then participates in the National Residency Matching Program with an independent Match number.
Prior studies of distraction osteogenesis in dog and rabbit models have shown predominantly intramembranous bone formation. Other models of fracture healing normally display mixtures of both endochondral and intramembranous bone formation. We have established a rat model of tibial lengthening that reliably reproduces the pattern of zonal osteogenesis previously observed in dog and rabbit models. A distraction rate of 0.25 mm twice a day with a 0-day latency period produced intramembranous bone with zones of progressive mineralization from collagen. With this protocol, rats bridged the distraction gap with a 25% increase in the tibial bone length. After 20 days of distraction and 50 days of consolidation, the three-point bending stiffness, as a percentage of the contralateral control, reached a level equivalent to that measured in the canine model for a 15% lengthening (28-day distraction and 84-day consolidation). Radiodensitometric analysis of the regenerate bones measured 97% of the unaffected contralateral tibial densities, and mineral analyses demonstrated that calcium and phosphorus levels in the regenerate bone reached 78% of contralateral tibial levels by day 70. We concluded that a rat model of distraction osteogenesis will be useful for a wide range of studies involving rapid intramembranous bone formation.