Improving estimation and prediction in linear regression incorporating external information from an established reduced model

We consider a situation where there is rich historical data available for the coefficients and their standard errors in a linear regression model describing the association between a continuous outcome variable Y and a set of predicting factors X , from a large study. We would like to use this summary information for improving inference in an expanded model of interest, Y given X , B . The additional variable B is a new biomarker, measured on a small number of subjects in a new dataset. We formulate the problem in an inferential framework where the historical information is translated in terms of nonlinear constraints on the parameter space and propose both frequentist and Bayes solutions to this problem. We show that a Bayesian transformation approach proposed by Gunn and Dunson is a simple and effective computational method to conduct approximate Bayesian inference for this constrained parameter problem. The simulation results comparing these methods indicate that historical information on E( Y | X ) can improve the efficiency of estimation and enhance the predictive power in the regression model of interest E( Y | X , B ). We illustrate our methodology by enhancing a published prediction model for bone lead levels in terms of blood lead and other covariates, with a new biomarker defined through a genetic risk score.     

Free-flap reconstruction of the scalp: donor selection and outcome

Wide, complex defects of the scalp caused by various insults always represent reconstructive challenges for surgeons. Our study group consisted of 18 patients (14 males and 4 females) with a mean age of 40.2 years. Nineteen free-tissue transfers were used to reconstruct the scalp defects. The selected cases included 8 latissimus dorsi muscle flaps, 3 latissimus dorsi myocutaneous flaps, 2 rectus abdominis muscle flaps, 3 omental flaps, 1 scapular flap, 1 radial forearm flap, and 1 groin flap. Twelve patients had acute or subacute wounds resulting from trauma or craniotomy, 4 had primary cancer, and 2 had neurofibromatosis. Commonly used recipient vessels were the superficial temporal artery and vein. No flap procedure had morbidity due to vessel compromise, and the overall flap success rate was thus 100%. No major donor-site morbidity was observed. All cases underwent primary closure of donor sites except for one receiving split-thickness skin grafting. In cases where muscle or omental free flaps covered skin grafts, patients were more satisfied because of increased durability and well-fitted wigs. We advocate variable free-tissue transfers for the reconstruction of large defects of the scalp related to the sizes, sites, and extents of the involvement.     

Orthodontic extrusion and implant site development using an interocclusal appliance for a severe mucogingival deformity: a clinical report

A multidisciplinary therapy used to treat a patient with a severe mucogingival deformity in the area of maxillary anterior teeth is presented. The simple technique uses an interocclusal appliance and elastic band for orthodontic extrusion to correct the mucogingival deformity and develop an implant site. This approach is designed to increase the amount of keratinized tissue and new alveolar bone, which are necessary for the development of an implant site. Clinical and radiographic examinations at the 5-year follow-up revealed a successful tooth replacement and improved esthetic appearance that was achieved with multidisciplinary treatment. The advantages and disadvantages of this technique are discussed.     

A comparative evaluation of different compensating curves in the lingual and labial techniques using 3D FEM.

Because adults dislike the visibility of orthodontic appliances, the use of the lingual orthodontic technique has increased over time. But few studies compare tooth movement of the lingual technique with that of the labial technique. In this study, human mandibular left teeth were aligned, and a 3-dimensional finite element model was made (consisting of 19382 nodes and 12150 elements). To compare the effect of compensating curves on canine retraction between the lingual and the labial orthodontic techniques, the compensating curve was increased on the.016-in stainless steel labial or lingual archwire, and a 150-g force was applied distally on the canine. The relative direction and the amount of tooth displacement of the finite element model were compared on a schematic displacement graph (magnified 10,000 times), and the compressive stress distributed on the root surface was observed. The pattern of tooth movement (with or without a compensating curve) was different between the labial and the lingual techniques. As the amount of compensating curve increased (0, 2, and 4 mm) in the archwire, the rotation and the distal tipping of the canine was reduced. The antitip and antirotation action of compensating curve on the canine retraction was greater in the labial archwire than in the lingual archwire.     

Effect of bismuth subgallate (local hemostatic agent) on wound healing in rats. Histological and histometric findings

The aim of this research was to evaluate the effect of bismuth subgallate on wound healing. In 40 Wistar rats, two standard wounds (3.5 mm x 2 mm) were made using a biopsy punch on the back of each animal. Test wounds were filled with bismuth subgallate and control wounds with 0.9% saline. At 1, 4, 7, 11 and 18 days, the qualitative evolution of the granulation tissue morphology was observed and digitalized histologic images were evaluated. There were no significant histological differences between test and control. Histometrically, there were statistically significant differences between test and control (ANOVA--days 1 and 4; Student t test, p < 0.05--days 7, 11 and 18) in terms of the following parameters: area of ulceration--day 1; distance between epithelial edges--day 4; area of granulation tissue--days 7, 11 and 18. It was concluded that bismuth subgallate is biocompatible to the healing tissue, and did not interfere with the normal development of wound healing.     

Fixed prosthetics with a connective tissue and alloplastic bone graft ridge augmentation: a case report

Augmentation of the partially edentulous ridge can significantly improve the final prosthodontic rehabilitation. For enhancing soft tissue contours in the anterior region, the subepithelial connective tissue graft is the treatment of choice. The combination of connective tissue grafts with alloplastic bone graft material can optimize the ridge augmentation and reduce post extraction defects. The aim of this clinical report is to describe the use of subepithelial connective tissue in conjunction with an alloplastic bone graft for augmentation of a maxillary anterior ridge prior to prosthetic rehabilitation.     

Paraffin-embedded tissue as a source of RNA for gene expression analysis in oral malignancy

OBJECTIVE: To assess the feasibility of using archival oral mucosal tissue to examine gene expression at the ribonucleic acid (RNA) level.
MATERIALS AND METHODS: We describe the isolation of RNA from 8 nm sections of formalin-fixed paraffin-embedded oral mucosal tissue. RNA was reverse transcribed and three candidate genes amplified by polymerase chain reaction (PCR). The ribosomal protein S14 gene is a housekeeping gene which has been used as an internal standard in several quantitative PCR protocols. The thymidine kinase (TK) gene is expressed at low levels in most tissues and, with a well-documented genomic organisation, is a useful tool for discrimination between genomic DNA and cDNA. The RIa gene is reported to be overexpressed in many cancer cell lines, in malignant tissue and in vitro transformed cellS. RESULTS: The S14 gene, the TK gene and the RIα gene of the cAMP-dependent protein kinase (PKA) were amplified successfully from formalin-fixed paraffin-embedded tissue sections. The TK primer pair is a useful additional tool in the unambiguous identification of RNA-derived species.
CONCLUSION: RNA suitable for reverse transcribed (RT)-PCR was extracted from archival oral mucosal tissue. This should permit rapid sequence analysis of transcribed tumor suppressor genes and oncogenes in this material. Furthermore, the RT-PCR approach described may allow quantification of gene expression in oral mucosal archival material processed in a standard fashion.