Biomedical subjects

Maria J Troulis

Publications and source records attributed to Maria J Troulis.

22 records · Page 2Linked to original sources

PubMed2002

Antiangiogenic therapy with interferon alpha for giant cell lesions of the jaws.

PURPOSE: Giant cell tumors are classified and treated based on their biologic behavior. We hypothesize that they are proliferative vascular lesions and would be expected to respond to antiangiogenic therapy. The purpose of this report is to present a treatment protocol consisting of enucleation, with preservation of vital structures, followed by subcutaneous interferon alpha. MATERIALS AND METHODS: Patients with a biopsy-confirmed giant cell lesion satisfying criteria for "aggressive giant cell tumor" were included. Instead of wide en bloc resection, lesions were enucleated and the patients started on interferon alpha-2 or beta (3,000,000 units/m(2)) 48 to 72 hours postoperatively. The subjects were followed by clinical examination and radiography, immediately after surgery and every 3 months until the bone cavity completely healed. Thereafter, follow-up was every 6 months. RESULTS: Eight patients (7 females), with a mean age of 18.7 +/- 11.1 years, have been enrolled. Six tumors were in the posterior mandible, and 2 were in the anterior maxilla. The mean size was 29.0 mm (range, 15 to 70 mm). All patients underwent enucleation. There were no postoperative complications, and all patients tolerated interferon. There was no evidence of tumor growth during treatment. Seven of 8 patients have completed interferon therapy, and there have been no recurrences during 1 to 6 years of follow-up. The other patient continues on treatment with no evidence of disease. CONCLUSION: Antiangiogenic therapy, in combination with curettage, is a promising strategy for treatment of aggressive giant cell tumors. Combined treatment results in a high rate of tumor control with decreased operative morbidity compared with conventional treatment.

Adolescent↗

PubMed2002

Changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Distraction osteogenesis (DO) is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint have not been well documented. The purpose of this study was to evaluate the effect of DO, at varying rates, on the mandibular condyle and articular disc. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0 day latency and rates of 1, 2, or 4 mm/d for a 12-mm gap. After the animals were killed (0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested and evaluated to determine changes in 1) condylar form and size, 2) condylar surface, and 3) the articular disc. RESULTS: Articular surfaces of the condyles in control animals were smooth, with no irregularities or erosions. In animals undergoing distraction, ipsilateral condyles showed increasing changes in morphology and AP dimension, and surface contour irregularities as the DO rate increased. These changes were present, but to a lesser degree, in the contralateral condyles. Articular discs of both ipsilateral and contralateral sides showed variable thinning at the medial aspect at end DO. After 90 days, changes in the condyles and discs were reduced by remodeling except in the 4 mm/d DO groups. CONCLUSIONS: Results of this preliminary study indicate that gross changes occur in condyles and discs after unilateral mandibular DO. These changes are more severe at faster distraction rates (4 mm/d) and tend to resolve during neutral fixation when a rate of 1 mm/d is used.

Adaptation, Physiological↗

PubMedDate not supplied

Osteoclastogenesis on tissue-engineered bone.

Bone remodeling plays an important role in bone function. To date, bone tissue-engineering research has focused primarily on bone formation from osteoblasts. This study demonstrates that osteoclastogenesis can occur on a mineralized polymer scaffold. Porcine bone marrow-derived mesenchymal stem cells (pMSCs) and hematopoietic cells were isolated from the bone marrow of Yucatan minipigs (n = 3) and cultured separately. pMSCs were differentiated into osteoblasts, seeded on porous poly(D,L-lactic-co-glycolic acid) foams, and cultured in a rotating oxygen-permeable bioreactor system. Once the cell-polymer constructs had started to mineralize, the hematopoietic cells were added and cocultured to include osteoclastogenesis. The cultured constructs were evaluated by histochemical and microscopic examination. Our results show that osteoblasts and osteoclasts were successfully differentiated from bone marrow on the scaffolds. This is the first demonstration of osteoclast formation on mineralized polymer surfaces.

Animals↗

PubMedDate not supplied

Tissue-engineered hybrid tooth and bone.

Tooth loss accompanied by alveolar bone resorption presents a significant clinical problem. We have investigated the utility of a tissue-engineering approach to provide corrective therapies for tooth-bone loss. Hybrid tooth-bone tissues were bioengineered as follows. Tooth implants were generated from pig third molar tooth bud cells seeded onto polyglycolide (PGA) and polyglycolide-colactide (PLGA) scaffolds, and grown for 4 weeks in the omenta of adult rat hosts. Bone implants were generated from osteoblasts induced from bone marrow progenitor cells obtained from the same pig, seeded onto PLGA fused wafer scaffolds, and grown for 10 days in a rotational oxygen-permeable bioreactor system. The tooth and bone implants were harvested, sutured together, reimplanted, and grown in the omenta for an additional 8 weeks. Histological and immunohistochemical analyses of the excised hybrid tooth-bone constructs revealed the presence of tooth tissues, including primary and reparative dentin and enamel in the tooth portion of hybrid tooth-bone implants, and osteocalcin and bone sialoprotein-positive bone in the bone portion of hybrid tooth-bone constructs. Collagen type III-positive connective tissue resembling periodontal ligament and tooth root structures were present at the interface of bioengineered tooth and bone tissues. These results demonstrate the utility of a hybrid tooth-bone tissue-engineering approach for the eventual clinical treatment of tooth loss accompanied by alveolar bone resorption.

Animals↗