Laboratory investigation; a journal of technical methods and pathology
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The effects of serum from children with cystic fibrosis and from normal children on the mucus-secreting, ciliated epithelium have been investigated in vitro using explanted tissue from rabbit lung. By optical and scanning electron microscopy, a sequence of structural changes is observed after incubation with cystic fibrosis serum; this sequence does not occur with normal serum. The earliest changes involve swelling of the goblet cells, with subsequent discharge of mucus onto the epithelial surface. ⋯ Finally, some shedding of ciliated cells occurs from the epithelium. These findings suggest that factors in cystic fibrosis serum cause discharge of mucus leading to a disturbance of the normal ciliary activity in the rabbit lung. It is postulated that such changes result in dysfunction of the mucociliary clearance mechanism and that this dysfunction may be a contributory factor to the pathogenesis of lung disease.
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The ultrastructure of rat inner medullary vasa recta was studied by both conventional transmission and freeze-fracture electron microscopy. The identify of descending and ascending vasa recta in the inner medulla was established by tracing outer medullary descending vasa recta and ascending vasa recta into the inner medulla, as well as by the incomplete carbon labeling technique to identify isolated descending vessels or loops. As in the outer medulla, descending vessels possess thick continuous endothelium with pinocytotic vesicles budding off the luminal and basal plasma membranes (more numerous in the latter location), but no fenestrae. ⋯ Intercellular junctions in both vessels are zonulae occludens with usually one, and uncommonly two or three zones of outer leaflet membrane fusion. Intramembranous particles are numerous in endothelial plasma membranes of descending vasa recta; similar particles are much fewer in corresponding ascending vasa recta endothelial plasma membranes. The ultrastructural differences between descending vasa recta and ascending vasa recta may reflect markedly different permeability properties, particularly to macromolecules, and may be relevant to recent functional studies on rat inner medullary vasa recta.
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Comparative Study
A comparative pathology study of myocardial lesions and atherosclerosis in Japanese men living in Hiroshima, Japan and Honolulu, Hawaii.
Autopsies were conducted on Japanese men from 45 to 71 years of age in Hiroshima, Japan (191 patients) and in Honolulu, Hawaii (298 patients). They were performed according to a common protocol. In both locations the patients studied were representative of decedents from population-based cohorts with respect to age and cause of death. ⋯ Large myocardial scars were 1.5 times more frequent in the men in Honolulu. It was characteristic of men in Honolulu that severe atherosclerosis and myocardial lesions appeared at younger ages than in those in Hiroshima. These data demonstrate that there is an increase in the frequency and severity of ischemic lesion in the myocardium of Japanese who have migrated to Hawaii and that this increase is the result of atherosclerosis of the extramural segments of the coronary arteries.
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A study of six patients with Reye's syndrome indicated that, by light microscopy, inflammation and necrosis of liver cells are especially prominent in fatal cases. Contrary to previous reports, electron microscopic examination indicated that, aside from loss of matrix dense granules, alterations in mitochondrial structure were minimal or absent. ⋯ No ultrastructural features served to distinguish patients who died from those who survived. Although derangement of mitochondrial function may be important in the pathogenesis of Reye's syndrome, such derangement is not necessary reflected in the ultrastructure of mitochondria.