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Biomedical subjects

M E Chang

Publications and source records attributed to M E Chang.

3 recordsLinked to original sources
PubMed2000

Nitric oxide formation from glyceryl trinitrate in the developing guinea-pig hippocampus.

Glyceryl trinitrate (GTN) is classified as an organic nitrate vasodilator drug. GTN is considered to be a prodrug because it undergoes biotransformation at its site of action to form nitric oxide (NO) or a NO adduct, which produces its pharmacologic effect. The objectives of this study were to determine whether the hippocampus can biotransform GTN to NO using aerobic conditions, and whether biotransformation of GTN to NO is age-dependent during postnatal life. Time-dependent formation of NO occurred during the incubation of 100 microM GTN with 2.5% (w/v) homogenate of guinea-pig hippocampus at 37 degrees C using aerobic conditions. GTN-derived NO formation was similar in magnitude for the three selected postnatal ages that were studied, that is, postnatal days 10, 20 and > 60. The data demonstrate that the capacity of the hippocampus for NO formation from GTN is fully developed in the guinea-pig in early postnatal life. In view of these findings, it is conceivable that a NO donor drug, selectively metabolized to NO in the hippocampus, could be a useful therapeutic intervention to mitigate structural and/or functional defects in this brain region resulting from decreased NO formation or availability.

Animals↗
PubMed2000

Application of the Urban Airshed Model to forecasting next-day peak ozone concentrations in Atlanta, Georgia.

Twenty-four to forty-eight-hour ozone air quality forecasts are increasingly being used in metropolitan areas to inform the public about potentially harmful air quality conditions. The forecasts are also behind "ozone action day" programs in which the public and private sectors are encouraged or mandated to alter activities that contribute to the formation of ground-level ozone. Presented here is a low-cost application of the Urban Airshed Model (UAM), an Eulerian 3-dimensional photochemical-transport grid model for generating next-day peak ozone concentration forecasts. During the summer of 1997, next-day peak ozone concentrations in Atlanta, GA, were predicted both by a team of eight forecasters and by the Urban Airshed Model in Forecast Mode (UAM-FM). Results are presented that compare the accuracy of the team and the UAM-FM. The results for the summer of 1997 indicate that the UAM-FM may be a better predictor of peak ozone concentrations when concentrations are high (> 0.095 ppmv), and the team may be a better predictor of ozone concentrations when concentrations are low (< or = 0.095 ppmv). The UAM-FM is also discussed in the context of other forecasting tools, primarily linear regression models and a no-skill, persistence-based technique.

Forecasting↗