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Biomedical subjects

M E Avery

Publications and source records attributed to M E Avery.

At least 19 recordsLinked to original sources

Pulmonary surfactant as a vehicle for intratracheal delivery of technetium sulfur colloid and pentamidine in hamster lungs.

Tracheal instillation of pentamidine in a surfactant vehicle may be an effective direct method of antibiotic delivery to the lungs. In 10 healthy hamsters, we compared the pulmonary distribution of 99mTc sulfur colloid (TcSC) mixed with pentamidine, using as a vehicle either surfactant (n = 5) or saline (n = 5). Each animal was instilled with 0.25 ml/kg of suspension containing 0.0018 mCi TcSC and pentamidine mixed with either surfactant or saline. After 4 h of spontaneous respiration, the lungs were excised, inflated to TLC, dried, and sliced into 3-mm cross sections from apex to base. Autoradiographs were examined to evaluate 99mTc distribution. The surfactant group had detectable radioactivity in 93% of all slices compared with 72% in the saline group (p = 0.02). Six slices per animal (43% of total) and their corresponding autoradiographs were analyzed for distribution of radioactivity. Lung slice area was determined by planimetry, and autoradiograph area was determined by video densitometry. We calculated the fraction of each lung slice with detectable radioactivity. The surfactant group had 41% of the lung slice areas exposed compared with 21% in the saline group (p = 0.02). The coefficient of variation of radioactive intensities within each slice was used as an index of spatial uniformity. There was a trend towards more uniform distribution in the surfactant group, with a narrower range of variation of intensities (1.51 to 2.56) than the saline group (1.95 to 6.47). We conclude that a surfactant vehicle significantly increases airspace deposition of TcSC and pentamidine instilled intratracheally in normal hamster lungs, and may improve uniformity of spread.

Animals

The care of infants and children.

The growth and development of pediatrics took place principally in the twentieth century. One result has been the reduction in deaths in the first year of life 165/1000 live births to 10/1000 live births in 1987. The birth rate was reduced by one-half during the same period. The challenges of the future are to consider the needs of American children in the context of the world's children, since isolation from global problems associated with logarithmic population growth in the developing countries and maldistribution of food is no longer possible. The time has come to consider the limits to application of our ever more sophisticated technology to support life at both ends of the spectrum of human life, the most immature and the most debilitated elderly. Human behavior continues to be unnecessarily destructive for children. Congenital AIDS and drug-abusing parents are catastrophic for the infant. Accidents remain the leading cause of death of children in America. Deaths from diarrheal diseases and malnutrition are the main causes of death of children in developing countries. Nearly all of these problems are preventable with the application of current knowledge. How could we have let the best interests of children slip so far down on our national list of priorities in health care?

Child

Is chronic lung disease in low birth weight infants preventable? A survey of eight centers.

Chronic lung disease in prematurely born infants, defined as the need for increased inspired oxygen at 28 days of age, was thought to be more common in some institutions than in others. To test this hypothesis, we surveyed the experience in the intensive care nurseries at Columbia and Vanderbilt Universities, the Universities of Texas at Dallas, Washington at Seattle, and California at San Francisco, the Brigham and Women's Hospital in Boston, Texas Children's Hospital in Houston, and Mt Sinai Hospital in Toronto. The survey included 1,625 infants with birth weights of 700 to 1,500 g. We confirmed the relationship of risk to low birth weight, white race, and male sex. Significant differences in the incidence of chronic lung disease were found between institutions even when birth weight, race, and sex were taken into consideration through a multivariate logistic regression analysis. Columbia had one of the best outcomes for low birth weight infants and the lowest incidence of chronic lung disease.

Bronchopulmonary Dysplasia

Characterization of bovine surfactant for infants with respiratory distress syndrome.

Exogenous surfactant treatment of surfactant-deficient disease states is now under study in a number of centers, using a variety of surfactant preparations. We have chosen one preparation because of its current and potential clinical usefulness, and we have characterized it using selected tests and assays that we thought would be necessary (although not necessarily sufficient) to justify extended clinical use. We found its lipid composition to resemble that of other surfactants derived from lung mince. There is little variation among several batches with regard to lipid composition or surface tension-lowering capability. Morphologic heterogeneity occurs in individual samples of pelleted material studied by electron microscopy. Arterial oxygenation is improved when the material is administered to animals depleted of surfactant. A low molecular weight protein was identified that reacted with antibody that specifically binds nonserum surfactant proteins in a number of animal species (including human and cow). The characteristics of this surfactant preparation should be useful for comparison as newer and simpler products become available.

Animals

Risk of respiratory distress syndrome after prenatal dexamethasone treatment.

A prospective double-blind randomized clinical trial was carried out to determine whether glucocorticoid treatment reduces the risk of respiratory distress syndrome (RDS) in prematurely born infants. There were 127 infants born to 122 mothers who received either steroid (dexamethasone phosphate) or placebo. No differences between groups occurred in risk factors for RDS (eg, prepartum asphyxia, male sex, cesarean section). When those who received a full course of dexamethasone therapy were compared with those who received placebo, a significant reduction was found in risk, severity, and deaths due to RDS. An increased incidence of infection in mothers treated with steroid was evident, particularly after premature rupture of membranes. We conclude that steroids are effective in reducing risk of RDS, but safer and more efficacious approaches for the prevention of RDS should be sought.

Clinical Trials as Topic

Bronchopulmonary dysplasia: possible relationship to pulmonary edema.

The pathogenesis of bronchopulmonary dysplasia is controversial. Oxygen toxicity, mechanical trauma to the lung secondary to respirator therapy, and congestive heart failure with a left to right shunt through a patent ductus arteriosus have all been implicated. Our data suggest that in addition to these three conditions, all of which are edemagenic, infants with bronchopulmonary dysplasia have a significantly greater mean fluid intake in the first five days of life when compared with infants with respiratory distress syndrome or patent ductus arteriosus alone. We suggest that the addition of a fluid load may potentiate the effects of other factors and increase the risk of bronchopulmonary dysplasia in infants with respiratory distress syndrome who require respiratory support.

Bronchial Diseases