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Biomedical subjects

E S Wright

Publications and source records attributed to E S Wright.

At least 19 recordsLinked to original sources
PubMed1990

Effects of chronic exposure to ozone on pulmonary lipids in rats.

Ozone is the most toxic component of photochemical oxidant air pollution. Exposure to high concentrations of ozone produces a variety of toxic effects in the lung, but it is not known to what extent prolonged exposure to low concentrations of ozone may contribute to the development of chronic lung disease. Phospholipids, important components of cellular membranes and surfactant, are necessary for the maintenance of normal lung structure and function. In order to test the effects of chronic exposure to environmentally relevant concentrations of ozone on phospholipid metabolism in the lung, rats were exposed to clean air or to 0.12, 0.25 or 0.50 ppm ozone for up to 18 months. The content and biosynthesis of phospholipids in both lung tissue and bronchopulmonary lavage fluid (surfactant) were measured. Incorporation of [14C]acetate into lung tissue phospholipids, an estimate of overall biosynthesis, decreased significantly at some time points in the study, while tissue phospholipid content tended to increase with both ozone concentration and with age. No changes were detected in phospholipid content of bronchopulmonary lavage fluid. These findings did not support the hypothesis that prolonged exposure of rats to environmentally relevant concentrations of ozone results in either qualitative or quantitative deficits in the pulmonary surfactant system.

Animals↗
PubMed1990

Cellular, biochemical and functional effects of ozone: new research and perspectives on ozone health effects.

Ozone, a toxic component of photochemical oxidant air pollution, has been the focus of considerable research efforts for several decades. In spite of this large body of work, questions remain as to the potential risks to human health represented by chronic low-level exposure to ozone. Newer studies in animals have provided fundamental information on the range of biochemical, functional and morphologic responses to ozone exposure. While the response to ozone exposure is extremely complex, some generalities have emerged which may aid attempts to apply the results of these studies to decisions regarding the protection of human health.

Animals↗
PubMed1990

Pulmonary response to ozone: reaction of bronchus-associated lymphoid tissue and lymph node lymphocytes in the rat.

The purpose of this work is to assess the effect of ozone, a reactive product of environmental photochemical oxidation, on lymphocytes of the lung. We exposed male Fischer rats to ozone at a concentration of 0.5 ppm for 20 hr/day for 1-14 days. Animals were treated with radioactive thymidine and were sacrificed at Day 1, 2, 3, 7, or 14 of exposure. Lungs and mediastinal lymph nodes were removed and prepared for histologic examination, evaluation of labeling indexes, and morphometric measurement. We examined two components of the lymphocyte response of the lung: the airway-related response, represented by the reaction of the bronchus-associated lymphoid tissue (BALT), and the deep lung-related response, represented by reaction of the mediastinal lymph node. Lymphocytes of both the BALT and the mediastinal lymph node showed elevated radioactive thymidine uptake; however, no evidence of cell death was observed at either site. The cells of the specialized epithelium covering the BALT (lymphoepithelium) showed increased vacuolization, indicating altered cellular function. The average size of BALTs was unchanged by ozone exposure. Under experimental conditions ozone can affect a variety of cells in the lung including bronchial epithelial cells, macrophages, and Type 1 cells. We have shown for the first time that in addition to these cells, the rat BALT also proliferates in response to ozone. In addition we confirm previous work in the mouse which shows that the mediastinal lymph node reacts as well. The airways can be affected by inflammation, can be targets of infection, and can respond to chemical irritants with bronchoconstrictive responses. They are an important target organ for hypersensitivity responses and are a primary site for pulmonary cancer formation. A role for lymphocytes has been implicated in each of these processes. Therefore, the clinical significance of ozone on BALT and mediastinal lymph node responses could be appreciable in terms of potentiation of, or protection against, such responses.

Animals↗
PubMed1990

Catheters: making an informed choice.

Catheters are used in over 10 per cent of hospital patients, but many nurses still have misconceptions about them. This two part series looks at the correct use of catheters and the problems associated with catheterisation.

Catheterization↗
PubMed1988

Effects of chronic exposure to ozone on collagen in rat lung.

Pulmonary fibrosis is a consequence of severe injury from some toxic agents including high doses of ozone. It is not known, however, whether chronic exposure to low doses of ozone, such as those encountered in polluted ambient atmospheres, could also result in abnormal accumulations of lung collagen. Rats were exposed to ozone for 20 hr per day, 7 days per week for 3, 6, 12, and 18 months at concentrations of 0.12, 0.25, or 0.50 ppm. Controls were exposed under identical conditions to purified air. Upon removal from the chambers, rats were euthanized and lung tissue slices incubated with [14C]proline. The incorporation of 14C into hydroxyproline and the total hydroxyproline content of lung tissue were measured as estimates of lung collagen synthesis and content, respectively. The formation of labeled hydroxyproline tended to decrease significantly with time in controls and at the three ozone doses. There were, however, no significant dose-related changes at any of the time points tested. Total lung hydroxyproline increased with age in all groups, but no dose-related changes were detected at any time point. It was concluded that chronic exposure of rats to ozone at concentrations which approximate ambient urban concentrations did not affect normal age-related changes in either synthesis or accumulation of lung collagen.

Animals↗
PubMed1987

DNA synthesis in pulmonary alveolar macrophages and type II cells: effects of ozone exposure and treatment with alpha-difluoromethylornithine.

An increase in the number of pulmonary alveolar macrophages (AM) can be induced by a number of toxic insults to the lung, including ozone, an important photochemical oxidant air pollutant. This increase could arise from an influx of monocytes from the vascular or interstitial compartments, or from proliferation of AM in situ. While proliferation of alveolar type II cells after oxidant exposure has been well documented, it is not clear whether AM are also capable of this response. Rats were exposed to air or to 0.12, 0.25, or 0.50 ppm ozone for 1, 2, 3, 7, or 14 d, 20 h/d. The labeling index in both AM and type II cells increased about 10-fold after 2 d of exposure to 0.25 and 0.50 ppm of ozone, but returned to control levels by the end of 1 wk of exposure. These changes closely paralleled the temporal and dose-response characteristics of changes in total lung DNA synthesis. alpha-Difluoromethylornithine (DFMO) administered to rats during a 2-d exposure to 0.50 ppm ozone did not inhibit the ozone-induced increase in labeling index in AM or type II cells, although evidence of inhibition of lung ornithine decarboxylase activity was obtained, and the ozone-induced increase in total lung DNA synthesis was inhibited by 23%. These results suggest that, like type II cells, AM are capable of entering the cell cycle and synthesizing new DNA in situ in response to short-term exposure to environmentally relevant doses of ozone, and that the ozone-induced stimulation of DNA synthesis in these cell types was refractory to inhibition by DFMO.

Animals↗
PubMed1987

Peritracheal membranous adipose tissue for early revascularization of the bronchial anastomosis.

The effect of a peritracheal wrap of membranous adipose tissue on revascularization of the bronchial anastomosis after left lung autotransplantation was evaluated in four groups of dogs. The bronchial anastomosis was performed just distal to the carina in groups 1 (6 dogs) and 2 (7 dogs) and as close to the lobar division as possible in groups 3 (14 dogs) and 4 (7 dogs). Peritracheal membranous adipose tissue was used in groups 1 and 3 only. The other two groups served as controls. Three dogs from group 2 had elastic Dacron fabric wrapped around the anastomotic site. Revascularization of the distal bronchus through the wrap was demonstrated in all dogs in groups 1 and 3, 7 days after surgery by postmortem injection studies but not in control groups 2 and 4, and serious bronchostenosis was also observed in the latter two groups. Histologic examination of the bronchial anastomosis revealed better structural preservation of the bronchus distal to the suture line with the adipose tissue wrap. The dogs with elastic Dacron fabric wraps showed poor structural integrity below the suture line (necrosis and calcification). Our results suggest that the level of bronchial anastomosis does not alter the healing process of the distal bronchus when a peritracheal membranous adipose tissue wrap is applied to the anastomotic site. They also indicate that the wrap is effective in restoring vascular flow across the suture line within 1 week of lung autotransplantation.

Adipose Tissue↗
PubMed1987

Wright's law.

Explore the source record for details and available documents.

Economics, Medical↗
PubMed1986

Surface-tension measurements of pulmonary lavage from ozone-exposed rats.

Ozone, an important component of photochemical air pollution, has been shown to cause morphological and functional changes in the lung after acute, high-level exposure in controlled animal studies. Previous exposures of rats to 0.8 ppm ozone for 18 h showed trends toward decreased lung volumes, as well as modifications in phospholipid composition of lung lavage fluid. These results suggested that exposure to ozone may have diminished the ability of surfactant to reduce surface tension. The purpose of this pilot study was to determine if changes in the surface tension of lavaged pulmonary surfactant occur with ozone exposure. The lavage fluid from rats exposed to ozone at 0.8 ppm for 18 h had a 360% increase in protein and a 30% increase in lipid phosphorus content. Lung lavage samples from ozone-exposed rats were more potent in reducing surface tension as measured on a Wilhelmy plate balance. This difference was evident whether determined with half the total lavage or with equivalent microgram amounts of lipid phosphorus. It is concluded that at this dose and duration of ozone exposure, contrary to our hypothesis, surface-tension-lowering ability of surfactant increases and therefore does not appear to be a contributory factor in the previously observed changes in pulmonary function.

Animals↗
PubMed1986

Effects of short-term exposure to diesel exhaust on lung cell proliferation and phospholipid metabolism.

The effect of exposure to diesel exhaust (DE) on DNA synthesis in lung tissue and type II cells was investigated. Parallel experiments with carbon black (CB) and NO2 were designed to mimic exposure to individual components of DE. Continuous exposure to 6 mg/m3 DE particulate or 7 ppm NO2 elicited significant increases in DNA synthesis and type II cell labeling index. The maximal response occurred after 2 days of exposure, and all measures returned to control levels after one week. Exposure to 6 mg/m3 CB did not cause similar changes, suggesting that the initial wave of cell proliferation elicited by DE exposure may be related to the presence of NO2 in the exhaust. In investigations of the effect of DE exposure on lung lipid metabolism, the incorporation in vivo of 14C-palmitic acid into lung tissue phosphatidylcholine increased three-fold after the first exposure day, when tissue palmitic acid content was significantly decreased and lavaged phospholipid (PL) increased. In vitro measures of PL biosynthesis showed no changes. These results suggest that exposure to a high concentration of DE results in immediate, transient changes in fatty acid and PL metabolism, but that these effects are not necessarily related to a stimulation of PL biosynthesis.

Aerosols↗
PubMed1986

Impact on surgery of preoperative localization of parathyroid lesions with dual radionuclide subtraction scanning.

In an effort to localize parathyroid lesions preoperatively, scanning with radioactive thallium and technetium was performed in 20 patients considered clinically to have hyperparathyroidism. In the 11 found at surgery to have single parathyroid adenomas, scanning correctly localized the lesion in 10; in the other patient the lesion was in the unscanned mediastinum. Preoperative scanning was not as rewarding in the seven patients with parathyroid hyperplasia. A thyroid lesion was the source of an abnormality seen on the parathyroid scan in one patient, while neck scanning and surgical exploration were negative in another. Comparison of the patients who had parathyroid adenomas localized in the neck with a control group of similar patients who did not undergo preoperative scanning showed that the average surgical time was reduced by 50% with preoperative localization and there was a decrease in the number of nonparathyroid tissue biopsies.

Humans↗
PubMed1985

Early bronchial revascularization with an intercostal pedicle graft following canine lung autotransplantation.

The contribution of an intercostal pedicle flap to early revascularization and healing of the bronchial anastomosis following lung autotransplantation was evaluated in dogs. Left lung reimplantation was performed both in 33 control dogs (group 1) and in 38 dogs in which a pedicled intercostal muscle graft was wrapped around the bronchial anastomosis (group 2). Radiologic injection studies, estimation of the cross-sectional area of the anastomosis and histologic examination to assess the degree of healing were made at autopsy - 7, 14 and 28 days respectively after transplantation. Within a week, the bronchial mucosa was more normal and the anastomosis substantially more patent in group 2 than in group 1 animals. This study indicates that the intercostal pedicle flap significantly improves bronchial healing by promoting revascularization across and beyond the bronchial anastomosis at least as early as 7 days after lung reimplantation.

Animals↗