Unstable oxygen supply and glaucoma.

The pathogenesis of the glaucomatous optic neuropathy (GON) is an ongoing bone of contention. While the role of intraocular pressure (IOP) is well known, it is also clear that a variety of other factors, particularly those of a vascular nature, are involved as well. In contrast to other eye diseases, it is an unstable oxygen supply, as opposed to chronic hypoxia, that contributes to GON. The major cause of fluctuations in the local oxygen tension is an unstable ocular blood flow (OBF). OBF, in turn, fluctuates if the IOP spikes, blood pressure drops, or OBF autoregulation is defective. The main reason for disturbed autoregulation is a primary vascular dysregulation (PVD), particularly in the context of the so-called Flammer syndrome. Unstable oxygen tension leads to local oxidative stress with many detrimental effects, such as the activation of glial cells, which alters their morphology and gene expression. As a consequence, the local concentrations of nitric oxide and the metalloproteinases increase. The metalloproteinases digest extracellular matrix and thereby contribute to tissue remodelling. The short-lived nitric oxide easily diffuses into the neighbouring neuronal axons, allowing a fusion with the superoxide anion and thereby generating the cell-damaging peroxynitrite. Both this tissue remodelling and damage of the axons contribute to the development and progression of GON.

Creating a school without walls and building a learning organization: a case study.

Abstract: This article describes the genesis of a "school without walls" philosophy and the implementation of learning organization principles at Boston University School of Dental Medicine (BUSDM). In Peter Senge's five-discipline approach to organizational learning, a learning organization is defined as "an organization that is continually expanding its capacity to create its future." It is an organization that changes and innovates based on continuous learning, which in BUSDM's case constituted learning from industry trends, patients, students, staff, faculty, and other key stakeholders. Most important, such organizations successfully translate that learning into effective action. It is this capacity to innovate and create change that is critical to competitive advantage and success in a changing environment. This case study of organizational change provides a discussion of the conceptual framework guiding the design and implementation of the learning organization and the chronology of transformation that occurred in three phases over a period of twenty years. We also describe the lessons we learned and the lessons that are still emerging.

Preventability of emergent hospital readmission.

To determine whether emergent readmissions within 30 days of discharge are potentially preventable, we prospectively studied all readmissions to the medical service of a university teaching hospital during a 4-month period. The 327 readmissions, including 42 patients who were readmitted more than once during the study period, accounted for 12% of medical admissions. Nearly 75% of readmissions were due to previously diagnosed medical conditions; complications of drugs or therapeutic procedures caused 29%, and patient compliance contributed to 11%. Three reviewers judged 28 (9%) readmissions to be potentially preventable. These 28 readmissions constituted 1% of all admissions to the medical service and did not result in any fatalities, indicating that the quality of care was generally very good. One third of the potentially preventable readmissions were thought to be related to medical system failures, one third to an unfulfilled hope that the patient would improve after discharge, and one third to other suboptimal judgements in evaluation or treatment. Of the 28 potentially preventable readmissions, 89% occurred within 10 days of discharge. We conclude that potentially preventable readmissions would nearly always be detected by review of readmissions within 10 days of discharge and that many may be amenable to systematic interventions such as standardized predischarge assessment and better coordination of post-discharge follow-up.

Age-related differences in electric shock detection and escape thresholds in Sprague-Dawley albino rats.

For both male and female Sprague-Dawley albino rats, shock detection thresholds decreased as a function of age over a range of 90 to 660 days of age. Shock escape thresholds also were found to vary inversely with age. The findings are discussed in light of previous shock threshold experiments and in terms of implications for studies of age-related learning changes.

A comprehensive approach to dental health in a school population.

A program to provide school children with dental health education and preventive services was initiated by the Boston University School of Graduate Dentistry. This program utilized several generally untapped resources. The emphasis was on classroom education using teachers who were motivated by special workshops as well as students of dental auxiliary training programs. These dental auxiliary students under the supervision of a dental health educator were used to educate the classroom teachers as well as to teach children in the classroom. Direct dental services were also provided in the program in the form of preventive services utilizing an unused dental chair available at a school.