Chronic tympanic membrane perforation repair with a collagen-based scaffold: An in vivo model.

OBJECTIVE: The aim of this study was to assess the in vivo efficacy of a novel regenerative collagen-based scaffold developed by the Royal College of Surgeons in Ireland in a chronic tympanic membrane perforation (TMP) using a chinchilla model. METHODS: Bilateral TMPs were induced in 17 mixed gender chinchillas using tympanic membrane resection followed by a mixture of topical Mitomycin C and dexamethasone for 3 days. These were monitored with weekly otoscopy for 8 weeks. Animals were excluded if signs of infection developed in the follow up period (n = 8). At 8 weeks, intervention began and 18 TMPs were assigned to either treatment with the collagen-based scaffold (treated group) or spontaneous healing (control group). Animals were euthanized 6 weeks post-intervention. Otoscopic imaging and auditory brain response (ABR) were conducted at baseline, 8 weeks post-TMP induction and 6 weeks post-intervention. All TMPs were then evaluated at 6 weeks post-intervention and bullae underwent histologic evaluation. RESULTS: At 6 weeks post-intervention, otoscopic imaging demonstrated various degrees of healing in the treated ears. The treated group was noted to have an increased rate of healing when compared to the control group. Histologic evaluation demonstrated a variation in the degree of perforation healing within groups, with some animals in the treated group showing high levels of perforation healing. At 8 weeks after the TMP procedure, most of the animals had worsened hearing response. At 6-week post the collagen-based scaffold treatment, about 50 % (4/8) of the treated ears had improved in hearing response as compared to those of non-treated ears. CONCLUSION: Given the initial histologic evidence of partial healing in scaffold-treated ears, the post-intervention period should be extended to monitor the potential for complete healing. Given the overall positive findings related to healing with the scaffold-treated ears, this material warrants further investigation.

Redefining disease? The nosologic implications of molecular genetic knowledge.

How will developments in genetic knowledge affect the classification of disease? Leaders in genetics have suggested that knowledge of the role of genes in disease can determine nosology. Diseases might be defined by genotype, thus avoiding the limitations of more empirical approaches to categorization. Other commentators caution against disease definitions that are detached from the look and feel of disease, and argue for an interplay between genotypic and phenotypic information. Still others attribute nosologic change to social processes. We draw on an analysis of the scientific literature, our conversations with genetics clinicians, and reviews of patient organization Web sites to offer a revised interpretation of the nosologic implications of molecular genetic knowledge. We review the recent histories of three diseases--hemophilia, Rett syndrome, and cystic fibrosis--to argue that nosologic change cannot be explained by either biologic theories of disease etiology or sociologic theories of social tendencies. Although new genetic information challenges disease classifications and is highly influential in their redesign, genetic information can be used in diverse ways to reconstruct disease categories and is not the only influence in these revisions. Ironically, genetic information is likely to play a central role in producing a new, but still empirical, classification scheme.

Understanding the new human genetics: a review of scientific editorials.

Developments in genetics are expected to have a profound impact on health and health care, yet much remains to be learned about how leaders of the research and clinical communities view and frame these expectations. We conducted a comprehensive review of editorials about developments in genetic medicine published in scientific journals, to understand what this elite group of commentators anticipate. Editorials are an important resource for understanding how the new genetics is understood and portrayed. They allow leaders of the research and clinical communities to communicate to each other and informed publics, and are a forum for the expression of widely shared elite beliefs and opinions. We analyzed selected editorials for content and metaphoric language to explore attitudes and expectations concerning developments in genetic science and technology. Our analysis suggests that a diverse group of leaders of the research and clinical communities are remarkably uniform in their discourse about the future of genetic medicine. Editorialists have great expectations for developments in basic science and in the comprehension and management of disease. They also anticipate important effects on health care, notably the health care professions, and on wider society. Yet editorialists do not discuss these prospects in a consistently positive or optimistic manner, and they utilize metaphoric imagery that emphasizes the inexorable nature of progress, and the sometimes ominous manner in which developments emerge. The dominant discourse of editorialists claims authority for clinicians and researchers and asserts a broad sphere of expertise, but it also positions these leaders as handmaidens of a science they do not control, and insists that their ultimate contribution is to prepare themselves and others for the inexorable march of progress.