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Biomedical subjects

Leon Chen

Publications and source records attributed to Leon Chen.

5 recordsLinked to original sources
PubMed2005

An 8-year retrospective study: 1,100 patients receiving 1,557 implants using the minimally invasive hydraulic sinus condensing technique.

BACKGROUND: For many clinicians, inadequate alveolar bone height and anatomical features of the maxillary sinus complicate sinus lift procedures and placement of endosseous implants. We present a new internal crestal approach that addresses these issues. METHODS: Sinus burs and condensers of increasing width are used in conjunction with pliable atraumatic bone grafting mixture and hydraulic pressure from a surgical handpiece. The risk of a membrane perforation is minimized when the surgeon's tactile skill is administered in a two-stage process to first loosen and then graft bone particulate under the Schneiderian membrane. Threaded implants can then be placed in the same visit and secured via primary closure. RESULTS: A retrospective investigation of 1,100 cases showed that eight implants failed and 14 required longer healing periods in patients with alveolar ridge heights varying between <1 to 5 mm. CONCLUSIONS: Our experience suggests that hydraulic sinus condensing is a predictable and minimally invasive alternative for prosthetic rehabilitation of maxillary anterior and posterior regions in the presence of anatomical restrictions to implant placement.

Alveolar Ridge Augmentation↗
PubMed2005

Teaching medical students research while reaching the underserved.

OBJECTIVES: This study's objective was to develop and evaluate the effectiveness of a 9-week summer training program for teaching medical students research, while performing community-based participatory research in an underserved area. DESCRIPTION: Interactive didactic sessions familiarized students with research methods. Concurrently, they designed and completed a participatory project with a community mentor. EVALUATION: Questionnaires were used to assess students' experience with the program, their project, and their mentors. Pretests and posttests assessed students self-perceived understanding of research principles. CONCLUSIONS: Evaluation indicated that the program increased understanding of the research process and acquainted students with caring for patients in medically underserved communities.

Education, Medical↗
PubMed2003

Inhibition of delta-protein kinase C protects against reperfusion injury of the ischemic heart in vivo.

BACKGROUND: Current treatment for acute myocardial infarction (AMI) focuses on reestablishing blood flow (reperfusion). Paradoxically, reperfusion itself may cause additional injury to the heart. We previously found that delta-protein kinase C (deltaPKC) inhibition during simulated ischemia/reperfusion in isolated rat hearts is cardioprotective. We focus here on the role for deltaPKC during reperfusion only, using an in vivo porcine model of AMI. METHODS AND RESULTS: An intracoronary application of a selective deltaPKC inhibitor to the heart at the time of reperfusion reduced infarct size, improved cardiac function, inhibited troponin T release, and reduced apoptosis. Using 31P NMR in isolated perfused mouse hearts, we found a faster recovery of ATP levels in hearts treated with the deltaPKC inhibitor during reperfusion only. CONCLUSIONS: Reperfusion injury after cardiac ischemia is mediated, at least in part, by deltaPKC activation. This study suggests that including a deltaPKC inhibitor at reperfusion may improve the outcome for patients with AMI.

Animals↗
PubMed2002

Root coverage with enamel matrix derivatives.

Different root coverage procedures have been used to treat cases of gingival recession defects involving single or multiple exposed root surfaces. A therapeutic advantage may be gained if periodontal regeneration is obtained in addition to coverage of the root with gingiva. This article describes the treatment of gingival recession by combining a surgical technique with an enamel matrix derivative.

Adult↗