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  • 1
    Electronic Resource
    Electronic Resource
    Inflammatory response of the lung to tungsten particles: An experimental study in mice submitted to intratracheal instillation of a calcium tungstate powder (1993)
    Springer
    Lung 171 (1993), S. 187-201 
    Details
    ISSN: 1432-1750
    Keywords: Tungsten ; Scanning electron microscopy ; Macrophages, alveolar ; Lavage, bronchoalveolar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Tungsten has been implicated as a cause of a severe form of pneumoconiosis in humans, the so-called “hard metal” lung disease. We have investigated the effect of intratracheal instillation of a powder of calcium tungstate on the pulmonary tissue of CD-1 mice. The tungsten-induced alterations were studied using 3 microanatomical methods: cytologic study of exudates obtained by bronchoalveolar lavage (BAL); histologic examination of paraffin-embedded sections of the lung; and scanning electron microscopic (SEM) examination of lung samples using x-ray microanalysis to detect tungsten in situ. The animals were sacrificed 1, 3, 7, 14, and 21 days after a single intratracheal instillation of 250 µg calcium tungstate particles suspended in 100 µl of saline. We found that the metal particles induced a marked inflammatory response in the bronchoalveolar space characterized by a biphasic attraction of leukocytes with cellular peaks observed at day 1 and 14. More than 50% of the BAL macrophages showed ingested tungsten. In the lung parenchyma, the inflammatory infiltrates were predominantly located at the periphery of the bronchiolar walls. From 7 days on after the tungsten deposition, large inflammatory exudates were seen invading focal areas of the alveolar domain of the lung. SEM views revealed that the tungsten particles could be inside alveolar macrophages, in cells making up the alveolar wall, or inside periacinar lymphatics. Our data document that tungsten particles cause a marked inflammatory response in the lung tissue and that the leukocyte exudates may invade alveolar areas of the lung. This strong inflammatory response may correspond to the early stages of the tungsten-induced “hard-metal” lung disease previously reported in humans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203719
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  • 2
    Electronic Resource
    Electronic Resource
    Distribution of calcium differs in relaxed and contracted myocardial cells of the rat (1981)
    Springer
    Cell & tissue research 221 (1981), S. 295-302 
    Details
    ISSN: 1432-0878
    Keywords: Cardiac muscle cells ; Calcium ; Sarcomere ; Ultrastructure ; Contraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myocardial cells from left ventricles of beating hearts of rats were fixed by immersion in an osmium tetroxide solution containing potassium pyroantimonate to study the electron-microscopic distribution of calcium, the cation being precipitated as an electron-opaque salt (calcium antimonate) by this cytochemical technique. The observed myocytes could be divided into two groups according to their contractile state, evaluated by sarcomere length measurements. In contracted cells (mean sarcomere length 1.43 μm) the intramyoflbrillar precipitate was confined to areas of I-bands bordering the A-bands, the intermyofibrillar space showing scarce content in reaction product. Relaxed cells (mean sarcomere length 1.69 μm) presented a heavy deposition of reaction product over the sarcomeres, the electron-opaque dots being absent on the H and Z bands. The sarcotubular system and mitochondria were also clearly marked by the reaction product. This second pattern of calcium distribution has not been previously described in heart muscle cells and is interpreted as corresponding to the phase of rise of intracellular calcium which is mediated by membrane depolarization. Our results suggest that different bands of heart sarcomeres show different abilities to bind calcium. The I bands retain the cation even in cells under sustained contraction, probably due to their content in calmodulin; Z and M bands are apparently not involved in calcium sequestration, whereas the content in calcium of the A bands seems to be dependent on the contraction-relaxation cycle of heart myocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216733
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  • 3
    Electronic Resource
    Electronic Resource
    Neoformation of blood vessels in association with rat lung fibrosis induced by bleomycin (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 238 (1994), S. 57-67 
    Details
    ISSN: 0003-276X
    Keywords: Scanning electron microscopy ; Lung fibrosis ; Corrosion casts ; Bleomycin ; Blood vessels ; Endothelial cell ; Collagen ; Bronchi ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We have used intratracheal instillation of bleomycin in rats to study the microanatomical changes of blood vessels associated with lung fibrosis. Bleomycin is a toxic cytostatic drug employed in classical models of lung fibrosis. Wistar rats were submitted to intratracheal injection of 1.5 units of bleomycin and sacrificed 2.5 months later, a timing when marked fibrosis of the lung is observed. We casted the vascular tree of the rat lungs by perfusion with a methacrylate resin. These caste were studied by scanning electron microscopy. Lung tissue was also studied by light microscopy and thin section electron microscopy. The major vascular modifications observed in the bleomycin-treated rats were: (1) neoformation of an elaborate network of vessels located in the peribronchial domains of the lung, and (2) distortion of the architecture of alveolar capillaries. By light microscopy, it was clear that the newly formed vascular network was located in regions of fibrosis (which in the resin casts were digested away). These neoformed vessels appeared to originate from bronchial arteries. Thin section electron microscopy revealed that endothelial cells of the neoformed vessels were plump, presented large nuclei, and showed numerous pinocytotic vesicles that were also observed in subendothelial pericytes. The alveoli of the bleomycin-treated rats were heterogeneous in size and shape in contrast with the homogeneity of alveoli of control animals. The alveolar capillaries of fibrotic lungs appeared to occupy a larger volume of the alveolar wall than alveolar capillaries of control rats. Our findings indicate that lung fibrosis encompasses marked changes of the vascular system, namely, the neoformation of vessels and the rearrangement of alveolar capillaries. These structural changes suggest that fibrotic transformation of the lung is associated with the local generation of angiogenic stimuli. © 1994 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092380108
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  • 4
    Electronic Resource
    Electronic Resource
    Identification of vascular sphincters at the junction between alveolar capillaries and pulmonary venules of the mouse lung (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 241 (1995), S. 383-390 
    Details
    ISSN: 0003-276X
    Keywords: Scanning electron microscopy ; Lung ; Corrosion casts ; Vascular sphincters ; Blood vessels ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: A peculiar feature of lung circulation in the lung is the pronounced variations in blood volume observed in alveolar capillaries that occur because of the changes in the conformation of the alveolar wall that are associated with the respiratory movements. This phenomenon has led to the postulate that mechanisms of postcapillary control of blood flow are to be present in the lung vessels. In the present study we searched for microanatomical evidence of vascular sphincters in the deep lung tissue of mice, namely in alveolar capillaries and pulmonary veins.Methods: We have used scanning electron microscopy (SEM) to examine two types of samples of normal lung tissue of CD-1 mice: 1) vascular corrosion casts made by vascular perfusion with Mercox® resin, and 2) routinely made gold/platinum-coated replicas of sectioned lung tissue.Results: Careful scrutiny of the vessels of the deep lung tissue led to the identification of sphincters in alveolar capillaries. These sphincters were located at the junction between capillary and pulmonary veins. They corresponded to areas to the vascular wall showing circular swellings where a radial organization was observed, since they were made up of alternating grooves and bulges. Transmission electron microscopy showed that smooth muscle cells participated in the formation of the sphincters.Conclusions: Our data reveal a new location for vascular sphincters in pulmonary vessels and, because these novel sphincters are located at the capillary-vein junction, they offer a structural setting for the existence of postcapillary control of blood flow in the pulmonary circulation of mice. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092410313
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  • 5
    Electronic Resource
    Electronic Resource
    Inflammatory macrophages in the dog contain high amounts of intravesicular ferritin and are associated with pouches of connective tissue fibers (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 190 (1991), S. 89-96 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: 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 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 fibroblasts.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001900108
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  • 6
    Electronic Resource
    Electronic Resource
    Morphological heterogeneity of the smooth endoplasmic reticulum in the Leydig cells of the boar testis (1983)
    Springer
    Cell & tissue research 228 (1983), S. 677-683 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Endoplasmic reticulum ; Leydig cells ; Boar ; Cholesterol crystals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of boar Leydig cells is re-examined in samples post-fixed with OsO4-K4Fe(CN)6, an elective method to preserve the ultra-structural detail of the endocrine testis. The cells show a pleomorphic arrangement of the smooth endoplasmic reticulum. Large “vesicle-like” dilatations are interspersed in the tubular network of this membrane system. The dilatations contain a flocculent material with a dense core and a dispersed peripheral rim. Additional features of boar Leydig cells revealed by OsO4-K4Fe(CN)6 treatment are parallel tubular arrays within residual bodies, and electron-lucent inclusions suggestive of crystals of cholesterol or its esters. These structural characteristics were not identified in previous electron-microscopic studies on Leydig cells of the boar or of other mammals. The unique components of boar interstitial cells described may be the morphological counterpart of the peculiar composition of testicular steroids secreted in this animal, namely low concentrations of androgens and large amounts of pheromones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211483
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