30 research outputs found
Adjunctive effect of hormone replacement therapy on periodontal treatment responses
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Development and validation of the Chinese version of the Reintegration to Normal Living Index for use with stroke patients
2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Three-dimensional virtual-reality surgical planning and soft-tissue prediction for orthognathic surgery
Complex maxillofacial malformations continue to present challenges in analysis and correction beyond modern technology. The purpose of this paper is to present a virtual-reality workbench for surgeons to perform virtual orthognathic surgical planning and soft-tissue prediction in three dimensions. A resulting surgical planning system, i.e., three-dimensional virtual-reality surgical-planning and soft-tissue prediction for orthognathic surgery, consists of four major stages: computed tomography (CT) data post-processing and reconstruction, three-dimensional (3-D) color facial soft-tissue model generation, virtual surgical planning and simulation, soft-tissue-change preoperative prediction. The surgical planning and simulation are based on a 3-D CT reconstructed bone model, whereas the soft-tissue prediction is based on color texture-mapped and individualized facial soft-tissue model. Our approach is able to provide a quantitative osteotomy-simulated bone model and prediction of postoperative appearance with photorealistic quality. The prediction appearance can be visualized from any arbitrary viewing point using a low-cost personal-computer-based system. This cost-effective solution can be easily adopted in any hospital for daily use.published_or_final_versio
Noninvasive Prenatal Diagnosis of Fetal Trisomy 18 and Trisomy 13 by Maternal Plasma DNA Sequencing
Massively parallel sequencing of DNA molecules in the plasma of pregnant women has been shown to allow accurate and noninvasive prenatal detection of fetal trisomy 21. However, whether the sequencing approach is as accurate for the noninvasive prenatal diagnosis of trisomy 13 and 18 is unclear due to the lack of data from a large sample set. We studied 392 pregnancies, among which 25 involved a trisomy 13 fetus and 37 involved a trisomy 18 fetus, by massively parallel sequencing. By using our previously reported standard z-score approach, we demonstrated that this approach could identify 36.0% and 73.0% of trisomy 13 and 18 at specificities of 92.4% and 97.2%, respectively. We aimed to improve the detection of trisomy 13 and 18 by using a non-repeat-masked reference human genome instead of a repeat-masked one to increase the number of aligned sequence reads for each sample. We then applied a bioinformatics approach to correct GC content bias in the sequencing data. With these measures, we detected all (25 out of 25) trisomy 13 fetuses at a specificity of 98.9% (261 out of 264 non-trisomy 13 cases), and 91.9% (34 out of 37) of the trisomy 18 fetuses at 98.0% specificity (247 out of 252 non-trisomy 18 cases). These data indicate that with appropriate bioinformatics analysis, noninvasive prenatal diagnosis of trisomy 13 and trisomy 18 by maternal plasma DNA sequencing is achievable
Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma DNA sequencing: large scale validity study.
To validate the clinical efficacy and practical feasibility of massively parallel maternal plasma DNA sequencing to screen for fetal trisomy 21 among high risk pregnancies clinically indicated for amniocentesis or chorionic villus sampling. Diagnostic accuracy validated against full karyotyping, using prospectively collected or archived maternal plasma samples. Prenatal diagnostic units in Hong Kong, United Kingdom, and the Netherlands. 753 pregnant women at high risk for fetal trisomy 21 who underwent definitive diagnosis by full karyotyping, of whom 86 had a fetus with trisomy 21. Intervention Multiplexed massively parallel sequencing of DNA molecules in maternal plasma according to two protocols with different levels of sample throughput: 2-plex and 8-plex sequencing. Proportion of DNA molecules that originated from chromosome 21. A trisomy 21 fetus was diagnosed when the z score for the proportion of chromosome 21 DNA molecules was >3. Diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were calculated for trisomy 21 detection. Results were available from 753 pregnancies with the 8-plex sequencing protocol and from 314 pregnancies with the 2-plex protocol. The performance of the 2-plex protocol was superior to that of the 8-plex protocol. With the 2-plex protocol, trisomy 21 fetuses were detected at 100% sensitivity and 97.9% specificity, which resulted in a positive predictive value of 96.6% and negative predictive value of 100%. The 8-plex protocol detected 79.1% of the trisomy 21 fetuses and 98.9% specificity, giving a positive predictive value of 91.9% and negative predictive value of 96.9%. Multiplexed maternal plasma DNA sequencing analysis could be used to rule out fetal trisomy 21 among high risk pregnancies. If referrals for amniocentesis or chorionic villus sampling were based on the sequencing test results, about 98% of the invasive diagnostic procedures could be avoided.published_or_final_versio
Advances in the surgical treatment of temporomandibular disorders
Pipes and pressure vessels are often subjected to operating environments where corrosion can degrade metal components and welds that join them. A program of regular system inspections is required to ensure the safe use of these systems and to reduce the possibility of costly shut-downs. This is especially true with recent changes in laws and regulations and social responsibility caused by environmental concerns which emphasize “zero” leaks in a wide variety of processing equipment. A comprehensive preventative maintenance program is needed to maintain high reliability in processing systems. An effective inspection strategy is essential in that program
Positron emission tomography/computed tomography true fusion imaging in clinical head and neck oncology: Early experience
Purpose: Positron emission tomography-computed tomography (PET-CT) is a new imaging modality that provides simultaneous functional and anatomic information. Its application in head and neck oncology is still evolving. Materials and Methods: Five illustrative cases who were scanned with this technique are presented. Results: The clinical application and impact on clinical management are described and discussed. Conclusion: Our experience indicates that PET-CT will assume a more important role than either CT, magnetic resonance imaging, or PET alone in head and neck cancer imaging. © 2005 American Association of Oral and Maxillofacial Surgeons.link_to_subscribed_fulltex
Image-Guided Minimally Invasive Surgical Access to the Temporomandibular Joint: A Preliminary Report
Purpose: To establish a protocol for image-guided minimally invasive surgical access to the temporomandibular joint (TMJ). Materials and Methods: This study involved 2 patients with TMJ pain and mandibular motion dysfunction. Axial magnetic resonance imaging (MRI) of the TMJ was obtained and loaded into an intra-operative navigation system to guide joint space injection. With a navigated syringe, 1 mL synvisc Hylan G-F 20 was directly injected into the superior and inferior joint spaces under navigation guidance. Results: With the assistance of an intraoperative navigational system, the TMJ MRI images were visualized in 3 dimensions and enabled guiding a needle into the superior and inferior joint spaces for therapeutic injection. The treatment outcome for both patients was satisfactory with improvement in pain score and mandibular motion. Conclusions: A protocol for image-guided minimally invasive surgical access to the TMJ was established. This could provide the technical basis for evaluation of accurate joint space intervention as a form of treatment of appropriate TMJ disorders. © 2006 American Association of Oral and Maxillofacial Surgeons.link_to_subscribed_fulltex