The Lymphatic Vessels of the Lung: Morphological Study

Grande, Nuno; Ribeiro, Joana; Soares, M; Carvalho, Elísio

doi:10.1159/000145706

Cited by 10 publications

(1 citation statement)

References 12 publications

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“…All animals were sacrificed by intravenous injection of a lethal dose of sodium pentobarbital followed by exsanguination. Samples of the regional (upper left) and medial (subcarina) hilar lymph nodes were collected (Grande et al, 1983). A sample of lung tissue was also harvested to check that successful instillation of CaWO, in the left upper lobe had been achieved.…”

Section: Experimental Protocolmentioning

confidence: 99%

Inflammatory macrophages in the dog contain high amounts of intravesicular ferritin and are associated with pouches of connective tissue fibers

1991

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We have studied the subcellular distribution of ferritin in inflammatory macrophages present in regional lymph nodes from dogs subjected to a pulmonary inflammatory reaction. The inflammatory reaction was induced by intrabronchial instillation of calcium tungstate (CaWO4), a water-insoluble powder. Ferritin was identified by electron microscopy, and its electron density was enhanced by the use of a modified Perls method. From day 14 on after the CaWO4 deposition, tungsten-positive lymph node macrophages showed a massive accumulation of ferritin. Most of the ferritin was stored in membrane-bounded vesicles that showed heterogeneous concentrations of the protein. A significant complement of ferritin was also detected in the cytoplasmic ground substance of phagocytes. The cell surface of the ferritin-rich, tungsten-positive macrophages showed deep infoldings that encompassed small pockets of connective tissue fibers. These features were not observed in control samples or in lymph nodes from dogs subjected to CaWO4-induced inflammation for periods shorter than 1 week. Our data indicate that inflammatory macrophages greatly increase their content of ferritin macrophages greatly increased their content of ferritin and that ferritin is stored predominantly by a membrane-bounded vesicular compartment. This is in contrast with suggestions that the inflammation-induced increase in macrophage iron is restricted to the labile pool of iron and it does not involve the iron bound to ferritin molecules. Our observation of nodules of connective-tissue fibers in intimate topographical association with ferritin-rich macrophages may indicate that the increase in intracellular ferritin in the macrophage is in some way related to the secretion of factors by the phagocyte that will stimulate fibrillogenesis by neighboring fibroblats.

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Section: Experimental Protocolmentioning

confidence: 99%

Inflammatory macrophages in the dog contain high amounts of intravesicular ferritin and are associated with pouches of connective tissue fibers

1991

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Forms of lung lymphatics: A scanning electron microscopic study of casts

Schraufnagel

1992

Anat. Rec.

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In a recent study, rats given monocrotaline underwent angiogenesis on their pleural surfaces. The rats also had novel structures in their bronchovascular bundles that were detected by scanning electron microscopy of vascular casts. These vessels could have been either new blood capillaries or dilated lymphatic capillaries. To determine if these structures were lymphatics or new blood vessels, specimens from animals that were undergoing angiogenesis were compared to those that were not. Finding similar structures in normal animals would imply that they were lymphatic. The second purpose of this work was to describe the three-dimensional anatomy of the lymphatics of the lung. Cast lymphatics were found in most lungs with edema or angiogenesis, but were rare in other conditions. The vascular structures in question were found in animals not undergoing angiogenesis and were, therefore, lymphatic. Additionally, scanning electron microscopy of casts showed several distinct forms of lymphatics in the lung. Prelymphatics are tissues planes beneath the pleura and around bronchovascular structures. They join reservoir, conduit or tubulo-saccular lymphatics. Reservoir lymphatics are broad ribbon-like structures with textured surfaces and small laterally branching pouches. They occur on the pleural surface, are closely linked with prelymphatics, and join conduit lymphatics. Conduit lymphatics are tubular structures that may contain valves, twist and go great distances without accepting tributaries. On the pleural surface, they may wind around blood vessels and vary greatly in diameter. Sacculo-tubular lymphatics surround arteries, veins and bronchioles. They have thin walls with wide saccular segments. They may be so dense that they form cylinders around the vessels or airways. Different forms of lung lymphatics suggest different function and potential.

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