Nonhuman Primate Lung Research Articles

Lower Respiratory Tract Structure of Laboratory Animals and Humans: Dosimetry Implications

Significant differences in lower respiratory tract structure exist both within species and among species at each level of anatomy. Irregular dichotomous and trichotomous branching patterns of airways are present in human and nonhuman primate lungs. In contrast, the dog and common laboratory rodents exhibit a predominantly monopodial branching system. The effects of these various branching patterns on airflow distribution, gas uptake, and the deposition of particles have not been sufficiently studied to determine the extent to which branching patterns impart regional inhomogeneities or local variations in the deposition of inhaled material. To date, detailed morphometric data have not been used to examine aerosol particle deposition. We have been using three-dimensional reconstruction techniques to examine various aspects of lung structure. Studies vary from the reconstruction of individual cells to reconstructing conducting airway and alveolar duct branching systems. When using physical models for dosimet...

Mast cell heterogeneity in higher animals: a comparison of the properties of autologous lung and intestinal mast cells from nonhuman primates.

The issue of mast cell heterogeneity has been investigated in nonhuman primates by a comparative examination of lung and intestinal mast cells. These cells were obtained in parallel from the respective tissues of individual monkeys by an identical enzymatic dispersion technique. Mast cells derived from the lungs differed from those derived from the intestine in that the majority of the former cell type could be stained with toluidine blue at pH 4 to 5, whereas the intestinal mast cells in the dispersed preparations required a more acidic pH (less than 1) to display metachromasia. In addition, the lung cells exhibited an increased content of the mast cell mediator histamine. Nonhuman primate lung mast cells were also quantitatively more responsive to an immunologic challenge than their intestinal counterparts in that they released a higher percentage of cellular histamine and generated more leukotriene C4 on stimulation. Considerable inter-animal variation was observed between the magnitude of mediator release from both mast cell types after anaphylactic activation, but evidence for the presence in nonhuman primates of the phenomenon of releasability was not obtained. The responsiveness of both cell types to a range of potential nonimmunologic secretagogues and anti-allergic agents, including compound 48/80, substance P, theophylline, and isoprenaline, was essentially similar. We conclude that mast cell heterogeneity in higher animals may be reflected more by cytochemical rather than by functional differences between mast cell classes.

Host Defense Deficiency in Newborn Nonhuman Primate Lungs

We have investigated two major aspects of the pulmonary host defense mechanism--alveolar macrophage function as a "first line of bacterial defense" and induced neutrophil migration into the lung as a "back-up defense." Chemotactic and phagocytic/killing assays revealed a functional deficiency in the alveolar macrophages of newborn primates. Serial bronchoalveolar lavage investigations revealed diminished neutrophil migration into the newborn primate lung. The overall pulmonary host defense capability in newborn primates was deficient. The results of this investigation may have direct clinical relevance to the susceptibility of newborns to infections and pneumonia.