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  • 1
    Electronic Resource
    Electronic Resource
    Expression of Cytokeratin 18 During Pre- and Post-Natal Porcine Lung Development (2002)
    Berlin, Germany : Blackwell Verlag, GmbH
    Anatomia, histologia, embryologia 31 (2002), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The expression pattern of the intermediate filament protein cytokeratin 18 (CK 18) is described during pre- and post-natal development of the porcine lung using a monoclonal antibody aginst human CK 18. Lungs from 16 foetuses in pseudoglandular, canalicular, saccular and alveolar stages of lung development and lungs from 12 pigs ranging in age from birth to 49 days after birth were studied by immunohistochemistry.In the early pseudoglandular stage of development (day 70 of gestation) all the columnar epithelial cells lining the tubular endbuds strongly expressed CK 18 predominantly in the apical cell compartment. A modest staining was found in the more cuboidal cells of the canalicular stage (day 80 of gestation) where the labelling occurred as a distinct positive rim at the apical cell membrane in most of the cells lining the canaliculi. In 96- and 100-day-old foetuses, parts of the gas exchanging area were formed as terminal sacs by extreme attenuation of the epithelium. In this stage, CK 18 was clearly detectable in the flat type I as well as in the cuboidal type II alveolar epithelial cells. A marked change of the CK 18 expression pattern occurred during formation of the alveoli by septal outgrowth and maturation of the epithelium in 105- and 111-day-old foetuses. Differentiated type I cells no longer expressed CK 18, whereas type II cells were still labelled. Moreover, a specific change in the subcellular distribution pattern from the luminal peripherie in immature porcine type II cells to a cytoplasmic localization in differentiated type II cells could be observed. Our investigation additionally demonstrated that the epithelium of bronchi, bronchioli and terminal bonchioli expressed CK 18 in all pre- and post-natal developmental stages. From the 96 days of gestation onwards the epithelial cells of developing bronchial glands were also labelled. Our results clearly show that during porcine lung development profound changes in the cellular expression pattern of CK 18 occur and that CK 18 can be regarded as a selective marker for differentiated porcine alveolar type II cells from the 105th day of gestation onwards. We also assume that the intermediate filament CK 18 could be of significance in the maturation process of the type II alveolar cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2002.00383.x
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  • 2
    Electronic Resource
    Electronic Resource
    Angiogenesis in the Bovine Corpus Luteum: An Immunocytochemical and Ultrastructural Study* (1999)
    Oxford, UK : Blackwell Science, Ltd
    Anatomia, histologia, embryologia 28 (1999), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Immediately after ovulation a neovascular response occurs at the level of the theca interna. Pericytes and endothelial cells of post-capillary venules locally remodel the surrounding stroma, elongate and migrate into the avascular granulosa folds of the ruptured follicle. In order to examine the composition of the extracellular matrix as well as the growth characteristics of these newly formed vessels, we used immunohistochemical and electron microscopic methods. Initial sprouts were characterized by the appearance of a fibrillary network of fibronectin along the main axis of the sprout. Type IV collagen stained weakly and extracellular deposits of laminin were amorphous and patchy around immature capillary sprouts. In advanced maturational stages of the sprouts the capillaries were surrounded by increased deposits of fibronectin, whereas laminin and type IV collagen displayed a distinct and well-developed line around endothelial cells and pericytes. These observations indicate that the microvascular extracellular matrix undergoes a series of quantitative rather than qualitative changes during capillary development before achieving final maturation. Ultrastructural analyses showed that early capillary sprouts in the bovine corpus luteum were usually preceded by pericytes migrating at the tips of the sprouts. Endothelial cells comigrated in cohesive cylindrical projections, forming immediately a slit-like lumen which satisfies the criteria of the intercellular canalization type. Pericytes at the tips of endothelial sprouts exhibited a slender, bipolar morphology and were regularly surrounded by fragmented basal lamina, which is well-developed around pericytes in a more proximal position of the sprout. The regular association of pericytes with the leading front of the capillary sprouts suggests that these cell types may serve as guiding structures aiding outgrowth of endothelial cells in the bovine corpus luteum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.1999.00195.x
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  • 3
    Electronic Resource
    Electronic Resource
    Cell-specific Localization of the CholecystokininA Receptor in the Porcine Pancreas (2000)
    Oxford, UK : Blackwell Science, Ltd
    Anatomia, histologia, embryologia 29 (2000), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cholecystokinin (CCK) produced in the mucosa of the upper small intestine exerts several biological functions. Its secretion in physiological amounts is modulated by the interaction of extracellular regulators and by binding to intracellular receptors of the target cells. The relative affinity of CCK to its receptor has been characterized in various biological and pharmacological studies and it is now well established that CCK has a higher affinity to the CCKA than to the CCKB receptor. Furthermore CCK influences the secretion of pancreatic enzymes in several species but very little is known about the relationship between CCK and the islet hormone-producing cells in the pig pancreas. The localization of this receptor at the cellular level showed conflicting results in animal studies and has not been described in pigs. The aim of the present study was to characterize the precise cellular location of the CCKA receptor in the porcine pancreas. Polyclonal antiserum was raised against the N-terminal epitope of the CCKA receptor molecule and used for localization studies. Using immunohistochemistry on methanol/acetic acid-fixed, paraffin-embedded pancreas, the CCKA receptor could successfully be localized in islet cells. Parallel staining of serial sections with antibodies directed against insulin and glucagon revealed colocalization with glucagon in alpha cells. No immunoreaction was found in the exocrine pancreas. Our results support the concept that in the porcine species the stimulation of the exocrine pancreas is mediated by the CCKB rather than the CCKA receptor, as it is known for the rat species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2000.00286.x
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  • 4
    Electronic Resource
    Electronic Resource
    Cytological ontogenesis and involution of the thymus and head-kidney in juvenile and old domestic carp: Is ageing in fish a chronological or growth-related phenomenon? (2001)
    Oxford UK : Blackwell Science Ltd.
    Journal of applied ichthyology 17 (2001), S. 0 
    Details
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Samples of the thymus and head-kidney of domestic carp (Cyprinus carpio) were studied in order to evaluate the process of functional and cytological change during ageing. We examined larvae from 6 days post-fertilization, 1- to 10-year-old fish from fishponds, and experimentally stunted 15-year-old fish that had attained no more than 100–120 mm total length (TL) and 18–20 g weight. The primordium of the thymus appears 6 days after fertilization as a group of non-specialized cells 0.8 mm3 in volume. Differentiation of cell types, especially thymocytes, starts in fry of 6 mm TL, and the thymus continues to enlarge, attaining 200 mm3 (±3.4 mm3) in 8-year-old fish of 550 mm TL. Throughout its development the thymus remains active, containing various forms of reticulocytes and thymocytes. The head-kidney appears in pre-hatching embryos on either side of the pharynx as renal units, each with a single glomerulus and a short renal tubule. During development the protonephridia pass through three functional stages: (1) excretory, as the primordial kidney, (2) in a mixed renal and glandular function, producing blood cells and adrenergic cells, and (3) in young fish of 80 mm TL and above, they continue to function as blood producing and endocrine organs. At this last stage the renal elements become degraded. The largest head-kidney measured had a volume of 8 cm3 (±0.8 cm3) in an 8-year-old fish weighing 6.5 kg. Retention of thymal cytological integrity in reproductive older carp and other fish would indicate that ageing in fish, and possibly also in other exothermic vertebrates, is not simply a time-related phenomenon, thereby differing greatly from similar processes in endothermic vertebrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0426.2001.00247.x
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  • 5
    Electronic Resource
    Electronic Resource
    Differential distribution of immunoreactive S-100 protein in mammalian testis (1994)
    Springer
    Histochemistry and cell biology 102 (1994), S. 241-245 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present study deals with the immunohistochemical localization of S-100 protein in the testes of seven mammalian species including rat, cat, dog, pig, sheep, cattle and horse. Significant differences are demonstrated in the cellular distribution and intensity of immunoreaction for the protein. In bull, ram, boar and cat tests S-100 protein was localized in the cytoplasm and nuclei of Sertoli cells. A particularly intense staining was seen in the modified Sertoli cells of the terminal tubular segment. With the exception of the cat and horse S-100 protein immunoreactivity was additionally found in epithelial cells of the straight testicular tubules and in the epithelial cells of the rete testis. Endothelial cells of capillaries, veins and lymphatic vessels are regularly S-100 immunoreactive in ruminants. Leydig cells were found to be strongly positive for S-100 protein in the cat and rat testes and to a lower degree in pig and horse testes. Finally a distinct immunostaining of peritubular cells was restricted to the testis of dogs and rats. The remarkable species-specific variations of immunoreactivity for S-100 protein in different cell types of the testis support the hypothesis that S-100 protein is a multifunctional protein and may have a different function in testicular physiology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00268901
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