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Biomedical subjects

Greg King

Publications and source records attributed to Greg King.

7 recordsLinked to original sources

FIZICS: fluorescent imaging zone identification system, a novel macro imaging system.

Constantly improving biological assay development continues to drive technological requirements. Recently, a specification was defined for capturing white light and fluorescent images of agar plates ranging in size from the NUNC Omni tray (96-well footprint, 128 x 85 mm) to the NUNC Bio Assay Dish (245 x 245 mm). An evaluation of commercially available products failed to identify any system capable of fluorescent macroimaging with discrete wavelength selection. To address the lack of a commercially available system, a custom imaging system was designed and constructed. This system provides the same capabilities of many commercially available systems with the added ability to fluorescently image up to a 245 x 245 mm area using wavelengths in the visible light spectrum.

Biological Assay↗

Expression of connective tissue growth factor in asthmatic airway smooth muscle cells.

There is strong evidence to implicate transforming growth factor-beta in the remodeling that occurs in asthma, as levels are increased in bronchial lavage fluid and gene expression is increased in bronchial tissue. Transforming growth factor-beta is also known to increase the release of collagen from airway smooth muscle. Here we identify for the first time a possible mechanism for the effects of transforming growth factor-beta. Transforming growth factor-beta specifically induces mRNA and protein for connective tissue growth factor in airway smooth muscle, and moreover, we report that the connective tissue growth factor response is greater in airway smooth muscle cultured from patients with asthma compared with patients without asthma. This occurs at both the level of mRNA (37.53 +/- 11.62- and 13.59 +/- 3.12-fold increase at 24 hours compared with time 0, respectively, p < 0.02) and protein production (67.57 +/- 27.80- and 3.58 +/- 0.6-fold increase at 24 hours compared with time 0, respectively, p < 0.03). The differential connective tissue growth factor response to transforming growth factor-beta in asthmatic airway smooth muscle identifies a potential role for connective tissue growth factor in the remodeling that is characteristic of severe persistent asthma.

Adolescent↗

Activation time and material stiffness of sequential removable orthodontic appliances. Part 1: Ability to complete treatment.

Recent advances in technology have led to the availability of sequential removable orthodontic appliances (aligners) to move teeth in a stepwise fashion (Invisalign, Align Technology, Santa Clara, Calif). This study was undertaken to compare 2 distinctly different materials (hard and soft) and 2 activation frequencies (1 week and 2 weeks) for this technique. Fifty-one subjects, stratified by peer assessment rating (PAR) and need for extractions, were randomly assigned to a hard or a soft plastic appliance, and a 1-week or 2-week activation time. The primary endpoint was the completion of the initially prescribed series of aligners. Changing aligners every other week was more likely to lead to completion of the initial series of aligners than changing aligners weekly (37% vs 21%). No substantial difference in the completion rate was observed for the soft versus the hard appliance (27% vs. 32%). The completion rate was highest (46%) among patients with PAR scores less than 15 and no planned extractions, and lowest (0%) among subjects who had 2 or more premolars extracted. All who completed their initial series of aligners required an additional series of aligners or fixed appliances to achieve the original treatment goals. This exploratory study suggests that subjects with a 2-week activation regimen, no extractions, and a low PAR score are more likely to complete their initial series of aligners.

Activator Appliances↗

Activation time and material stiffness of sequential removable orthodontic appliances. Part 2: Dental improvements.

Fifty-one patients were enrolled in this study to explore the treatment effects of material stiffness and frequency of appliance change when using clear, sequential, removable appliances (aligners). Patients were stratified based on pretreatment peer assessment rating (PAR) scores and need for extractions. They were randomized into 4 treatment protocols: 1-week activation with soft material, 1-week activation with hard material, 2-week activation with soft material, and 2-week activation with hard material. Patients continued with their protocols until either the series of aligners was completed, or until it was determined that the aligner was not fitting well (study end point). Weighted PAR score and average incisor irregularity (AII) indexes were used to measure pretreatment and end-point study models, and average improvement was compared among the 4 groups. In addition to the evaluation of the 4 treatment groups, comparisons were made of the individual components of the PAR score to determine which occlusal components experienced the most correction with the aligners. The percentages and absolute extraction space closures were evaluated, and papillary bleeding scores before and during treatment were compared. Although no statistical difference was observed between the 4 treatment groups, a trend was noted with the 2-week frequency having a larger percentage of reduction in weighted PAR and AII scores, and greater extraction space closure. Anterior alignment was the most improved component, and buccal occlusion was the least improved. When analyzed by type of extraction, incisor extraction sites had a significantly greater percentage of closure than either maxillary or mandibular premolar extraction sites. A statistically significant decrease in mean average papillary bleeding score was found during treatment when compared with pretreatment scores, although this difference was not clinically significant.

Activator Appliances↗