BOVINE FETAL LUNG DEVELOPMENT
BOVINE FETAL LUNG DEVELOPMENT
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Date
1985
Authors
HAMBOLU, JOSEPH OLAJIDE
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Abstract
Fetal lung tissue obtained from abattoirs was examined
histochemically using alpha-napthyl butyrate (nonspecific method), to
defect the presence of pulmonary alveolar macrophages (PAM). Esterasepositive
alveolar macrophages, which appear in the alveolar septa and
lumina were first seen at 240 days of gestation. These macrophages were
identified by the presence of numerous diffuse intensely red-stained
granules in the cytoplasm. Macrophages at 240 days were 15.88 ± 1.67 Urn
(S.E.) (N=30) in size and in most cells the esterase-positive granules
were sparsely distributed in the cytoplasm. Only four out of eight
lungs examined at 240 days were positive for alveolar macrophages.
However, all the lungs (N=10) examined from 250=day-old fetuses
contained esterase-positive macrophages, which were distributed both in
the alveolar septa and alveolar spaces. Compared to macrophages of the
240-day fetuses, those at 250 days were signi ficantly larger, 16.91 ±
1.33 μm (S.E.) (N=30) (P<0.05). Type II pneumocytes and T lymphocytes
were not confused with PAM because in all lungs, T lymphocytes contained
a single, small, esterase-positive granule compared with the numerous
diffuse esterase-positive granules in PAM while type II pneumocytes
reacted negatively to nonspecific esterase stain during lung
development.
The time of appearance of alveolar macrophages coincides with the
first appearance of surfactant at the alveolar surface-lining layer
which suggests that macrophages could be involved with the clearing of
excess surfactant being produced.
Description
A DOCTOR'S DISSERTATION
submitted in partial fulfillment of the
requirements for the degree
DOCTOR OF PHILOSOPHY
Department of Anatomy and Physiology
KANSAS STATE UNIVERSITY
Manhattan, Kansas
Keywords
BOVINE,, FETAL,, LUNG,, DEVELOPMENT