title: The influence of a bisphosphonate on bone generation determined using a chick-femur model.
abstract: OBJECTIVE
  To determine the direct influence of a bisphosphonate (pamidronate) delivered by one of two carriers, on bone generation in chick-femurs supported by chick egg chorio-allantoic membranes.
  
  
  METHODS
  Twenty chick femurs freshly harvested from fertilized eggs were randomly allocated to two groups: (i) Affi-Gel blue bead carrier (n=10); and (ii) hydroxyapatite bead carrier (n=10). The femurs in each group were further randomly divided into control (n=4) and experimental (n=6) subgroups. Carriers charged with PBS solution or 0.1 M pamidronate were delivered into the bone marrow of each femur at its mid-portion through a needle puncture. Each femur was then grafted onto the chorio-allantoic membrane of a chick egg and incubated for 7 days. Each experimental and control subgroup femur yielded four histological sections at the puncture site, constituting the test and inter-bone controls. In addition, two histological sections were also obtained from 400 to 450 μm away from each end of the experimental puncture site to act as the intra-bone controls. Bone generation was quantified and the ratio of cross-sectional area of bone marrow to circumference of bone (outcome measure) was determined using a software package, Image-Pro(®) Plus. The data were analysed using Mann-Whitney tests and Wilcoxon signed rank tests.
  
  
  RESULTS
  The outcome ratio in the test group was significantly (P<0.001) smaller than both the inter-bone and intra-bone control groups. There was evidence of increased bone formation directly over the pamidronate-charged carriers.
  
  
  CONCLUSIONS
  The test model established that pamidronate had a positive effect on bone generation over a period of 7 days, regardless of the carrier type.
authors.affiliation: Unit of Endodontology, UCL Eastman Dental Institute, University College London, London, UK.
authors.forename: L-L
authors.initials: LL
authors.lastname: Wei
authors.forename: K
authors.initials: K
authors.lastname: Gellynck
authors.forename: Y-L
authors.initials: YL
authors.lastname: Ng
authors.forename: K
authors.initials: K
authors.lastname: Gulabivala
authors.forename: P
authors.initials: P
authors.lastname: Buxton
mesh_terms: D000287:Administration, Topical; D000818:Animals; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D002642:Chick Embryo; D004396:Coloring Agents / Q000008:administration & dosage; D004164:Diphosphonates / Q000008:administration & dosage*; D004337:Drug Carriers / Q000008:administration & dosage*; D005269:Femur / Q000187:drug effects* / Q000254:growth & development; D006882:Hydroxyapatites / Q000008:administration & dosage; D009924:Organ Culture Techniques; D010012:Osteogenesis / Q000187:drug effects*; D000077268:Pamidronate; D011897:Random Allocation; D014227:Triazines / Q000008:administration & dosage
chemical_list: D050071:Bone Density Conservation Agents; D004396:Coloring Agents; D004164:Diphosphonates; D004337:Drug Carriers; D006882:Hydroxyapatites; D014227:Triazines; C012842:Cibacron Blue F 3GA; D000077268:Pamidronate