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Biomedical subjects

Melanie Robinson

Publications and source records attributed to Melanie Robinson.

2 recordsLinked to original sources
PubMed2003

Surgical therapies for the treatment of gingival recession. A systematic review.

BACKGROUND: A variety of soft tissue augmentation procedures directed at root coverage have been documented in the literature utilizing autogenous or allogenic soft tissue grafting or guided tissue regeneration (GTR). RATIONALE: The purpose of this systematic review was to assess the literature regarding the efficacies of various surgical gingival augmentation procedures relative to clinical and patient-oriented outcomes. FOCUSED QUESTION: What is the effect of surgical therapy for root coverage in patients with gingival recession compared with other treatment modalities or baseline values? SEARCH PROTOCOL: PubMed and the Cochrane Oral Health Group Trials Register were searched to identify human studies in English investigating the therapeutic use of a soft tissue surgical procedure to treat gingival recession. Searches were performed for articles published by April 2002. SELECTION CRITERIA: Initial screening of identified abstracts accepted all studies evaluating surgical intervention of gingival recession. Independent review by 2 reviewers evaluated full-text reports regarding study characteristics. Only those studies determined to be randomized clinical trials (RCTs) were included in the final analysis. DATA ANALYSIS AND COLLECTION: Outcome measures included changes in root coverage, clinical attachment levels (CAL), probing depth (PD), and width of keratinized tissue (KT). The only data suitable for meta-analysis were comparisons of the efficacy of connective tissue grafts with GTR. MAIN RESULTS: 1. Thirty-two articles (total study population: 687) met the criteria for RCTs: 11 (population: 286) related to various autogenous soft tissue augmentation procedures; 18 (population: 360) to GTR; and 3 (population: 41) to allogenic soft tissue augmentation. 2. Meta-analysis identified greater gains in both root coverage and keratinized tissue width for connective tissue graft procedures compared to GTR. 3. No other data were compatible with meta-analysis. REVIEWERS' CONCLUSIONS: 1. Soft tissue augmentation procedures are effective means of obtaining root coverage. 2. Connective grafting techniques appear to have an advantage over GTR. 3. There is a need for further efficacy studies and for investigation of these procedures relative to patient-oriented outcomes such as esthetics, root sensitivity, and postoperative morbidities.

Connective Tissue↗
PubMed2002

Polymorphism at position 97 in MHC class I molecules affects peptide specificity, cell surface stability, and affinity for beta2-microglobulin.

The two mouse MHC class I alleles, L(d) and L(q), share complete amino acid sequence identity except in the alpha2 domain, where they differ at six positions. Despite their similarity, L(q) has a stronger association with beta2-microglobulin (beta2m), is expressed at higher levels on the cell surface, demonstrates an increased cell surface half-life, and has fewer open forms on the cell surface than L(d). To determine the basis for their phenotypic differences, L(d) molecules containing chimeric L(d)-L(q) alpha2 domains were characterized, and these analyses implicated residue 97 (L(d)Trp and L(q)Arg) as the polymorphic site responsible for the disparity in beta2m association between the two alleles. Single substitution analysis at this site (L(d)W97R and L(q)R97W) confirmed this. Furthermore, the L(d)W97R mutant molecule has a longer cell surface half-life than either L(q) or L(d), and fewer open forms of L(d)W97R are observed on the cell surface. In addition, both L(d)W97R and L(q) possess decreased binding affinity for the L(d)-restricted tum(-) P91A(14-22) peptide compared with L(d). Collectively, these results and the known location of Trp(97) in the peptide binding cleft of L(d) strongly suggest that the substitution of Arg for Trp(97) in L(d) alters the peptide binding cleft, increasing its affinity for endogenous peptides, which results in greater cell surface stability and better retention of beta2m. Furthermore, these results imply that Trp(97) plays an important role in the ability of L(d) to efficiently participate in alternative MHC class I Ag presentation pathways.

Alleles↗