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Biomedical subjects

Stuart Carmichael

Publications and source records attributed to Stuart Carmichael.

4 recordsLinked to original sources

Contour and volume assessment of repairing mandibular osteoperiosteal continuity defects in sheep using recombinant human osteogenic protein 1.

BACKGROUND: This study describes the contour and volume of reconstructed mandibles using recombinant human osteogenic protein 1. MATERIAL AND METHODS: The investigation was conducted on six adult sheep, where a unilateral 35 mm parasymphyseal osteoperiosteal continuity defect of the mandible was created. Recombinant human osteogenic protein 1 and type-I collagen (as carrier) were applied to the defects. Radiographic and ultrasonographic examinations were carried out at day 1 of the surgery and 2, 4, 8, and 12 weeks following the surgery. The animals were then sacrificed 3 months after the operation. Postmortem CT-scan was performed for volumetric, cross-sectional area, height and width measurements. RESULTS: Ultrasound was more efficient than radiographs in demonstrating early callus formation at 2 weeks, while radiographic evidence of bone formation was consistently detectable only after 4 weeks. Using the combination of recombinant human osteogenic protein type 1 and type-I collagen resulted in twice the volume, cross-sectional surface area, and height when compared with those of the corresponding region of the contra-lateral non-operated side of the mandible. CONCLUSION: Within 3 months, recombinant human osteogenic protein type 1 on type-I collagen carrier failed to restore the original contour and volume of mandibular osteoperiosteal continuity defects.

Animals↗

Type I immune-mediated polyarthritis in dogs: 39 cases (1997-2002).

OBJECTIVE: To determine clinical signs, laboratory findings, relationship to vaccination, and response to treatment for type I immune-mediated polyarthritis (IMPA) in dogs. DESIGN: Retrospective study. ANIMALS: 39 dogs PROCEDURE: Clinical records and radiographic reports from 3 university referral hospitals were reviewed. Clinical signs, laboratory and investigative findings, relationship to vaccination, and response to treatment were evaluated. RESULTS: Clinical signs and initial laboratory and clinical investigative findings were frequently abnormal but were nonspecific and not associated with likelihood of recovery. Time of vaccination was not associated with onset of disease. Chemotherapeutic immunosuppression resulted in complete cure in 56% of dogs. Continuous medication was required in 18% (7/39) of dogs, relapses were treated successfully in 13% (5/39) of dogs, and 15% (6/39) of dogs died or were euthanatized as a result of disease. CONCLUSIONS AND CLINICAL RELEVANCE: The possible involvement of vaccination in type I IMPA was not made clear from this study because of the small population size. Signalment, clinical signs, and results of diagnostic tests other than multiple synovial fluid analyses were generally nonspecific. Most dogs with type I IMPA responded to initial immunosuppressive treatment, but 31% (12/39) of dogs relapsed, required further treatment, or both.

Animals↗

A minimally invasive novel design for a vascular-pedicled bone segment for experimental studies of reconstruction of mandibular defects.

We describe a new minimally invasive vascularised bone segment (VBS) for experimental reconstruction of the mandible. The study was validated and the feasibility was tested on fresh sheep cadavers. The integrity of the arterial blood supply was confirmed using inferior dental artery static arteriography. A pilot investigation was conducted on two adult sheep. Two full thickness bone cuts 35 mm apart were created in the parasymphyseal region. The inferior dental neurovascular bundle was preserved at the posterior bone cut but not anteriorly. A VBS was created, pedicled only on the inferior dental artery. The continuity of the mandible was maintained using fixation plates and the animals were followed up for 12 weeks. There was complete bony union and restoration of approximately 80% of the bony strength. The model is minimally invasive, reduces the operating time, and does not require special equipment and skills in microvascular anastomosis.

Animals↗