Library

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 2000-2004  (25)
  • 1975-1979  (563)
  • 1890-1899
  • Ultrastructure  (588)
  • 101
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 197 (1979), S. 413-419 
    ISSN: 1432-0878
    Keywords: Luteal cells ; Secretory granules ; Sheep ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corpus luteum of the sheep has been examined at the mid-stage of the estrous cycle when progesterone secretion is active. Secretory granules are associated with the secretion of this hormone, and the evidence indicates that the granule membrane becomes incorporated into the plasma membrane during exocytosis. Further evidence of this process has been obtained from studies on the uptake of horseradish peroxidase by the luteal cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 102
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 199 (1979), S. 373-386 
    ISSN: 1432-0878
    Keywords: Hypogastric ganglion (rat) ; Vacuolated neurons ; Catecholamine fluorophore ; Ultrastructure ; Testosterone ; Castration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vacuolated neurons (VN) of the main hypogastric ganglion of the male rat were studied using the formaldehyde-induced fluorescence (FIF) method for the histochemical demonstration of catecholamines. Microspectrofluorimetry was performed to identify the fluorophores and to quantify the FIF. The thiocholine method (Koelle-Gomori) was used to demonstrate acetylcholinesterase activity. The fine structure of the VN was studied using glutaraldehyde/OsO4 fixation. (1) In the untreated adult male rat VN represent only a small population of the total number of hypogastric neurons (0.8–1.2%). The vacuoles are similar to those of the VN from the corresponding female ganglion. (2) The VN are considered to be adrenergic due to the nature of their fluorophore, indicating a primary catecholamine. (3) The first VN appear in the hypogastric ganglia at the age of 7 weeks. After testosterone administration to young rats, VN are found at the age of 4 weeks. (4) The basic fine structure of the VN is similar to that of other ordinary neurons of the hypogastric ganglia. (5) The content of the vacuoles could not be identified. (6) Indications of degeneration were not observed in the VN. (7) The VN are interpreted as being a functional stage of the “short” adrenergic neurons, which are under the control of steroid hormones. (8) Fifteen months after castration, no VN could be found in the hypogastric ganglia, while their number was normal in the corresponding control animals.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 103
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 199 (1979), S. 519-528 
    ISSN: 1432-0878
    Keywords: Filum terminale ; Spinal cord ; Glial cells ; Ultrastructure ; Frog (Rana pipiens)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filum terminale, or terminal portion of the spinal cord, was studied in normal adult frogs (Rana pipiens) by means of light and electron microscopy. Astroglial cells are the predominant elements in this region. The rostral portion of the filum terminale consists mainly of (1) a peripheral dense ring of myelinated and some unmyelinated nerve fibers, and processes of astrocytes terminating at the subpial space; (2) an intermediate zone, in which astrocytes are the main cellular elements in addition to a few degenerated neurons; and (3) a central region where the central canal is lined by dark and light ependymal cells. In the caudal portion of the filum terminale, the amount of neuropil is greatly reduced. This region is formed mainly by astrocytic glial cells and very few neuronal elements. The central canal in the caudal portion is located ventrally and contains a lining consisting almost exclusively of dark ependymal cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 104
    ISSN: 1432-0878
    Keywords: Pars distalis ; Graft ; Ultrastructure ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intact female rats received transplants of two hypophysial partes distales under the kidney capsule. The plasma levels of prolactin were determined, and the ultrastructure of the grafted gland was studied 15, 45 and 90 days after the operation. Although prolactin levels in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in the 45-day samples. Parallel ultrastructural changes suggest that between the 45th and 90th postoperative day a process is initiated leading to hyperplasia and hypertrophy of prolactotrophs.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 105
    ISSN: 1432-0878
    Keywords: Thyroid follicular cells ; Basal lamina, biosynthesis ; Cellular interaction ; Cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present. The present findings suggest an epithelial origin of the basal lamina resulting from an interaction with mesenchymal cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 106
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 200 (1979), S. 257-271 
    ISSN: 1432-0878
    Keywords: Anococcygeus muscle ; Innervation ; P-type nerves ; Purinergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60–70 % of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85–110nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed “small p-type” (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 107
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 200 (1979), S. 299-309 
    ISSN: 1432-0878
    Keywords: Germ-free mice ; Inflammation ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peritoneal macrophage ultrastructure was analysed stereologically in germ-free mice given a single intraperitoneal injection of sterile, pyrogen-free saline. Thus the stimulant was non-particulate, non-antigenic and inorganic, and effects of immune reactions were minimal. Macrophages were recovered 1, 6, 24 and 72 h after stimulation. A sequence of structural alterations is reported which may be fundamental to macrophage activation. The plasma membrane and nuclear envelope increased in area within only 1 h of saline injection. During the next 5 h loss of plasma membrane, probably by pinocytosis, caused cellular “rounding” and clear-cut alteration in surface configuration. At the same time lysosome-like granules enlarged but decreased in number. By 24 h most cellular structures and compartments (including the plasma membrane) were enlarged. Morphological evidence of nuclear activation accompanied a rather modest enlargement of the nucleus at this stage. The RER hypertrophied last and must, therefore, be judged sufficient in resident macrophages to support the initial growth response which results after stimulation. Thus hypertrophy was observed eventually in every structure examined. Even the minimally activated macrophages resident in the peritoneum of germ-free mice respond readily to stimulation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 108
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 200 (1979), S. 193-203 
    ISSN: 1432-0878
    Keywords: Mosquitoes ; Midgut ; Ultrastructure ; Stereology ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Morphometrische Untersuchungen des Magenepithels von A. aegypti weisen darauf hin, daß die Verdauung des ersten Blutmahls in eine Reihe von Phasen gegliedert werden kann, die sich mit physiologischen Daten aus der Literatur korrelieren lassen. In einer Phase Ia (0–10 h nach Blutmahl [BM]) entfalten sich die “whorls” des rauhen endoplasmatischen Retikulums, die Golgi-Zonen werden größer, und das basale Labyrinth wird erweitert. Dies stimmt mit Synthese- und Sekretionsprozessen (z.B. peritrophische Membran, Esterasen, Lipasen) und mit Transportvorgängen durch das Magenepithel überein. In Phase Ib (10–20 h nach BM) nehmen die gemessenen zellulären Parameter weiter zu und weisen damit auf hohe Synthese- und Sekretionsaktivitäten (z.B. Verdauungsenzyme) hin. In Phase Ic (20–30 h nach BM) zeigen die an Synthese und Sekretion beteiligten Zellstrukturen, in Übereinstimmung mit der maximalen Proteasenaktivität im Darm, immer noch hohe Werte. Vergrößerte Mikrovillioberfläche, auffallende Lipideinschlüsse und Auftreten von Glykogendepots im Magenepithel deuten auf erhöhte Resorptions-, Speicher- und Transportfunktionen der Zellen hin. In Phase II (30–36 h nach BM) läßt sich anhand der strukturellen Veränderungen der Wechsel von Synthese- und Sekretionvorgängen zu Resorption, teilweiser Speicherung und Transport von Verdauungsprodukten erkennen. In Phase III (36–72 h nach BM) wird der Zellapparat in Übereinstimmung mit dem Ende der Verdauung reduziert. Lipid- und Glykogendepots werden mobilisiert und verschwinden fast vollständig aus den Magenepithelzellen.
    Notes: Summary Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0–10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10–20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20–30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30–36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36–72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelum.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 109
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 200 (1979), S. 291-298 
    ISSN: 1432-0878
    Keywords: Excitatory synapse ; Lateral line-canal organ ; Synaptic body ; Ultrastructure ; Lota lota (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the afferent synapse in hair cells of the lateral line-canal organ was studied using different fixation and staining techniques. Glutaraldehyde-fixed tissue without post-osmication, contrasted by section staining with uranyl acetate and lead citrate, was compared with (a) osmium tetroxide-fixed tissue followed by the same staining procedure, and with (b) glutaraldehyde-fixed tissue, block-impregnated with phosphotungstic acid (PTA). The results reveal a pronounced heterogeneity in the composition of the synaptic body, reflecting regional differences in chemical affinity to the fixatives and staining agents. It is proposed that the “intracleft substance”, the synaptic structure defined by the PTA staining technique, is actually due to the glutaraldehyde fixation procedure and is apparently the outer leaflet of the postsynaptic membrane. A special technique that allows alternate sections of a series to be differentially stained for electron microscopy is proposed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 110
    Electronic Resource
    Electronic Resource
    Springer
    Protoplasma 100 (1979), S. 73-83 
    ISSN: 1615-6102
    Keywords: Bivalve ; Fertilization ; Laternula limicola ; Sperm-egg interaction ; Temporary-acrosome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural studies on sperm-egg interaction at the time of fertilization inLaternula limicola were performed. The “temporary-acrosome” did not change morphologically while the sperm passed through the egg investments. At the onset of sperm entrance into the egg, however, the temporary-acrosome and mitochondria were eliminated from the sperm. Afterwards the sperm was engulfed by the egg surface without membrane fusion of the gametes. After entry the sperm nucleus was surrounded by four membranes: the plasma membranes of the egg and of the sperm, and the membranes of the sperm nuclear envelope. As the sperm nucleus differentiated into the male pronucleus, the plasma membranes of both the sperm and egg were initially vesiculated, then dispersed into the egg cytoplasm. Finally, the sperm nuclear envelope changed into the male pronuclear membrane accompanying sperm chromatin dispersion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 111
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 39-57 
    ISSN: 1432-0878
    Keywords: Midgut (Collembola) ; Ultrastructure ; Cytochemistry ; Renewal ; Ageing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The midgut cells of Tomocerus minor (Insecta, Collembola) were examined with the electron microscope and cytochemically. The midgut epithelium consists of a series of cells characterised by numerous mineral concretions scattered throughout the cytoplasm. Mitochondria are abundant; microvilli are well developed at the apical surface of the cell. A zonula continua (continuous junction) characterises the apical contact region of these cells. Polysaccharides, glycoproteins and carbohydrate components have been demonstrated on the surface of microvilli. Peritrophic membranes surround the food bolus and preserve midgut cells from mechanical abrasion. Lysosomes are present during the alimentary period and show strong acid phosphatase activity. During an intermoulting cycle, two stages can be observed: (1) the postexuvial feeding period during which cytoplasmic extrusions appear at the apical part of the cell: lysosomes increase in number and autophagic vacuoles appear. (2) The preexuvial fasting period; a new epithelium grows beneath the old one and pushes it into the lumen. Degeneration processes can be observed in the old epithelium. This excretory reactivity of the midgut epithelium has been compared to the cycle of the cuticle.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 112
    ISSN: 1432-0878
    Keywords: Liver ; Goldfish ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A re-examination of goldfish liver was made through the use of SEM of fractured samples and TEM of ultrathin-sections and freeze-etch replicas. Several new hepatic fine structures described in the present study are morphologically similar to those reported previously in many higher vertebrates including mammals. Hepatic sinusoids of goldfish contain fenestrations which are arranged into sieve plates. Although the hepatic plates are made up of two layers of hepatocytes, the parenchymal cells of goldfish liver are morphologically similar to mammalian hepatocytes, particularly with respect to the sinusoidal surfaces which are studded with numerous microvilli. The intercellular surfaces of hepatocytes have both nexus and desmosomal junctions, similar to those found in various epithelial cells of higher vertebrates, as cell attachments and communication foci. Tight junctions are found mainly between the openings of the intracellular bile canaliculi and the intralobular bile ductules which are situated in the center of the bicellular hepatic plate.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 113
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 385-395 
    ISSN: 1432-0878
    Keywords: Uterus ; Endometrium ; Smooth muscle ; Culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Primary cultures initiated from normal human uterine endometrium after total enzymatic dissociation contained epithelioid cells and smooth muscle cells. The smooth muscle cells were subsequently isolated by differential trypsinization and grown in culture for 36 ± 4 generations. Ultrastructural examination of log and post-confluent cultures of cells at low and high population doubling levels revealed characteristics similar to those of published reports on other smooth muscle cells studied in vivo and in vitro. Among the common features present were: (a) abundant bundles of 60–70 Å myofilaments; (b) branched mitochondria; (c) stacks of cisternae of rough endoplasmic reticulum; (d) caveolae intracellulares; (e) nexuses. Other features included ovoid nuclei, a well developed Golgi apparatus and abundant free ribosomes. The subcultured cells exhibited features of dedifferentiation in the log phase of growth and at post-confluency. However, the post-confluent cells showed characteristics indicating redifferentiation back towards their in vivo morphology. Smooth muscle cells isolated from endometrial curettings may provide a useful model for biochemical and pharmacological studies of a cell type derived from a hormonal target tissue as the cells “age” in culture.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 114
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 449-454 
    ISSN: 1432-0878
    Keywords: Gastric epithelium (Rat) ; Phagocytosis ; Cell loss ; Aspirin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastric surface epithelial cells (SEC) from fed rats, from rats fasted for 16 h and from mucosae exposed in an ex-vivo chamber to 16 mM aspirin for 5 min were examined by transmission electron microscopy. SEC have the capability to phagocytose adjacent epithelial cells and parietal cells. Phagocytosis is rare in mucosae from fasted animals but common in fed animals or after brief exposure to aspirin. Phagocytic capabilities are not restricted to the progenitor zone but exist throughout the surface epithelium. Phagocytosis may provide a mechanism for the removal of damaged or senescent cells from the surface epithelium.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 115
    ISSN: 1432-0878
    Keywords: Interrenal tissue (birds) ; Ultrastructure ; Corticotropin ; Adenohypophysectomy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adrenal glands from ACTH-treated intact ducks and chronically adenohypophysectomized ducks showed clear zonation into a subcapsular zone (SCZ) and an inner zone (IZ). Adenohypophysectomy caused ultrastructural changes in the IZ but not in the SCZ cells. These included increases in lipid droplets, changes in mitochondrial cristae from tubular to shelf-like, and changes in the shape of the nuclei from spherical to crenated. These changes were reversed by treatment with ACTH. Also, cells of the IZ, but not the SCZ, of adrenals from intact birds given ACTH showed more SER, more dense bodies, fewer lipid droplets and more prominent Golgi complexes. IZ cells incubated in buffer containing no ACTH developed mitochondria with shelf-like cristae and numerous opaque granules in the matrix. Exposure to buffer containing ACTH caused the mitochondrial cristae to become tubular and the matrix granules either decreased in number or disappeared. The granules could be extracted by incubating sections with chelating agents. The mitochondria in SCZ cells did not respond structurally to the presence of ACTH in the incubation medium but the matrix granules, like those in IZ cells, responded to the presence of chelating agents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 116
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 511-518 
    ISSN: 1432-0878
    Keywords: Rabbit ; Aortic body ; Chemoreceptors ; Stereology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The chief cells of the aortic body (subclavian body) of adult New Zealand white rabbits were examined by ultrastructural stereological analysis. The chief cell nuclei occupy 26.5% of the total volume. Dense-core vesicles account for 16.5% of the cytoplasmic volume, followed by mitochondria (11.6%), endoplasmic reticulum (3.3%), and Golgi apparatus (0.6%). The dense-core vesicles measure approximately 131.6nm in diameter (corrected) and exhibit a heterogeneous size distribution. Both perivascular adrenergic nerve terminals and presumptive afferent terminals presynaptic to the chief cells are observed. The mean synaptic vesicle size of the terminals adjacent to chief cells is 54 nm. The heterogeneous size distribution of the dense-core vesicles of chief cells may indicate the storage of different biogenic amines and/or different secretion or maturation states within the chief cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 117
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 201 (1979), S. 479-486 
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Cercaria ; Striated tail muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The electron microscopic study of the tail of Cercaria chackai reveals that it contains four sets of striated muscle bundles located central to the nonstriated circular and longitudinal muscles. The striated muscle consists of longitudinally oriented lamellar myofibres. Each myofibre contains a single “U” shaped myofibril. The banding pattern is analogous to that of vertebrate striated muscle. The sarcolemma is a simple surface membrane. There are no transverse tubular extensions of sarcolemma. The sarcoplasmic reticulum (SR) is very well developed with cisternae, tubules, and vesicles. SR cisternae form dyadic couplings with the sarcolemma. There is a set of flattened tubules of SR origin traversing the myofibril exactly at the Z region. These tubules are unique to the striated muscle of the cercarian tail and may have functional significance. A diagrammatic reconstruction of the myofibre is presented.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 118
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 202 (1979), S. 33-39 
    ISSN: 1432-0878
    Keywords: Gregarina ; Ultrastructure ; Gram negative bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An investigation of bacteria-like structures, which are found in large numbers in the endoplasm of the eugregarine, Gregarina garnhami, was carried out using light and electron microscopy. Gram staining indicates that these structures are gram negative; they show orange fluorescence when stained with acridine orange. Ultrastructural observations show that they resemble the endosymbiotic bacteria found in other protozoan species. Some of these structures appear to be dividing, and the possibility that these structures are in fact bacteria is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 119
    ISSN: 1432-0878
    Keywords: Pancreatic endocrine cells ; Enteroendocrine cells ; Ultrastructure ; Cyprinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic endocrine cells of Barbus conchonius are concentrated in a large (principal) islet, located near the gall bladder, and in a number of smaller islets. Five types of endocrine cells can be distinguished in these pancreatic islets: B cells, A1 (or D cells), 2 types of A2 cells (A2r cells with round granules; and A2fl cells with flocculent granules) and a scarce 5th cell type. The hormones produced by B and A2fl cells are probably insulin and glucagon respectively. The A2r cell contains granules with the same diameter as the granules of the enteroendocrine type III cell of the gut. Both cell types may resemble the enteroglucagon-producing EG cell of mammals. The function of the A1 cells, which are frequently found without secretory granules, and of the 5th cell type, will be discussed. The pancreatic islets of B. conchonius are strongly innervated, which suggests the presence of a direct nervous control system. Some intermediate or mixed cells containing exocrine and endocrine A2r granules are found contiguous with the principal islet. The origin of pancreatic endocrine cells is also the subject of discussion.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 120
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 202 (1979), S. 453-460 
    ISSN: 1432-0878
    Keywords: Collagen ; Nerves ; Ganglia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerves and ganglia from a variety of fish, amphibian, reptilian and mammalian species were studied by optical and electron microscopy. Observations using the Picrosirius-polarization method strongly suggest that two different types of collagen fibers are present in the connective tissues of nerves and ganglia. Electron microscopy of nerves and ganglia showed the presence of two different collagen fibril populations, distinguishable on the basis of diameter, located in different compartments of these structures. Thicker fibrils are present in nerve and ganglionic epineurium. Thinner fibrils are present in the endoneurium, surrounding nerve fibers and ganglionic cells, and between the concentric layers of perineurial cells. These results were consistently observed in all species studied and very probably represent a general phenomenon in vertebrates.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 121
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 519-524 
    ISSN: 1432-0878
    Keywords: Y-organ ; Moulting gland ; Astacus ; Steroid production ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The electron microscopical investigation of Y-organs of Astacus astacus revealed that during intermoult (stage C) the cytoplasm is poorly developed and that it increases at premoult (stage D). It then shows the typical signs of steroid production, namely agranular endoplasmic reticulum and mitochondria of the tubular type. Furthermore, a larger type of mitochondria with a regular pattern of internal structure is described.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 122
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 531-539 
    ISSN: 1432-0878
    Keywords: Fiber types ; Red muscle ; Semitendinosus muscle ; Ultrastructure ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The semitendinosus muscle of the rabbit is composed of a homogeneous fiber population. Fiber typing was carried out by means of light and electron microscopy according to which this muscle exhibits structural features that are either characteristic for both ‘red’ and ‘white’ fibers, or that do not allow for any classification according to the A-, B-, C-fiber system. Hence the long-held assumption that the semitendinosus muscle of the rabbit represents a classical paradigm of a ‘red’ muscle should be revised in light of the present results.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 123
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 197 (1979), S. 39-59 
    ISSN: 1432-0878
    Keywords: Lamina ganglionaris ; First, second order neurons ; Neuroanatomy ; Ultrastructure ; Hemipterans (Notonecta glauca, Corixa punctata, Gerris lacustris)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuronal elements, i.e. first and second order neurons, of the first optic ganglion of three waterbugs, N. glauca, C. punctata and G. lacustris, are analyzed on the basis of light and electron microscopy. Eight retinula cell axons, leaving each ommatidium, disperse to different cartridges as they enter the laminar outer plexiform layer. Such a pattern of divergence is one of the conditions for neuronal superposition; it is observed for all three species of waterbugs. The manner in which the receptors of a single bundle of ommatidia split of within the lamina, whereby information from receptors up to three or five horizontal rows away can converge upon the same cartridge, differs among the species. Six of the eight axons of retinula cells R1-6, the short visual fibers end at different levels within the bilayered lamina, whereas the central pair of retinula cells R7/8, the long visual fibers, run directly through the lamina to a corresponding unit of the medulla. Four types of monopolar cells L1–L4 are classified; their branching patterns seem to be correlated to the splitting and termination of retinula cell axons. The topographical relationship and synaptic organization between retinula cell terminals and monopolar cells in the two laminar layers are identified by examination of serial ultrathin sections of single Golgi-stained neurons. An attempt is made to correlate some anatomical findings, especially the neuronal superposition, to results from physiological investigations on the hemipteran retina.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 124
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 197 (1979), S. 105-112 
    ISSN: 1432-0878
    Keywords: Thymus ; Myoid cells ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical and ultrastructural properties of myoid cells in the thymus of the frog were investigated and compared with properties of skeletal muscle fibres. The histochemical reactions of phospholipids, phosphorylase, succinic dehydrogenase and adenosine triphosphatase activities in myoid cells were characterized by considerable variability. Individual myoid cells apparently possess different enzyme activities which correspond to different stages of development, maturity and degeneration of these cells. The mature mononucleated myoid cells have similar enzymatic properties to the fast muscle fibres of the frog. This finding has been extended by ultrastructural observations. Features, typical of fast muscle fibres of the frog, e.g. the presence of the M-line, straight and narrow Z-line and well developed triads were found in the majority of mature myoid cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 125
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 197 (1979), S. 165-167 
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Chick embryo ; Muscular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary New Hampshire chickens, homozygous for inherited muscular dystrophy, display clinical manifestations at an early age. A fine structural examination of embryos from this strain shows marked degenerative changes four days prior to hatching. The Z bands appear to dissolve progressively to the point where finally the myofibrils become uniformly dense with no detectable banding patterns.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 126
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 197 (1979), S. 113-135 
    ISSN: 1432-0878
    Keywords: Domestic fowl ; Ultimobranchial gland ; Parathyroid gland ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the polymorphic vesicular component of the ultimobranchial gland of the domestic fowl (Gallus gallus domesticus) has been described in detail, together with the structure of the cell strands interconnecting the vesicles and the parathyroid nodules lying within the ultimobranchial stroma. The vesicles frequently appear to arise from the nodules by way of the cell strands. The strands show a structure of their component cells intermediate between that of the parathyroid and the vesicular cells, although the position at which the strand changes from an essentially parathyroid structure to an essentially vesicular structure is very variable. The degree and kind of secretory activity within different cell types has been described. A review of the structure of ultimobranchial glands throughout the vertebrates shows that similar tissue with a similar secretory potential has been observed in all vertebrate classes, suggesting a functional significance for this part of the gland.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 127
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 203 (1979), S. 311-320 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Acipenseridae ; Ultrastructure ; Quantitative analysis ; Spawning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The percentage of peptidergic (A1 and A2) and adrenergic (B) neurosecretory terminals was studied in the neurohypophysis of sexually mature female sturgeons. Neurosecretory terminals of the A2 type prevail in the neurohypophysis, whereas A1 and B terminals are rare. The activity of these types of terminals was established (1) during upstream migration, (2) shortly after spawning, and (3) three to six weeks after spawning. Terminals of B type are the most active elements during all the periods studied. These elements become strongly activated in sturgeons during upstream migration, i.e., earlier than the peptidergic neurosecretory terminals. Peptidergic terminals, especially elements of type A2, become synchronously and strongly activated in fish shortly after spawning. In the late postspawning period neurosecretory terminals of all three types become synchronously inactive, persisting in a quiescent state in comparison to the two previous periods. The appearance of neurosecretory material discharged into the intercellular clefts by exocytosis correlates on the whole with the activity level of the A1 and A2 terminals in each individual studied. A functional correlation exists between the activity of the peptidergic and adrenergic neurosecretory terminals in the neurohypophysis. The data obtained are discussed with reference to a concept regarding spawning in some fish species as a physiological stress (Polenov et al., 1976). A possible dual control (peptide and monoamine neurohormones) over the function of visceral organs and glandular cells of the intermediate lobe of the hypophysis is also suggested (Polenov, 1970, 1975, 1978; Polenov and Belenky, 1973).
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 128
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 198 (1979), S. 373-380 
    ISSN: 1432-0878
    Keywords: Ventral cochlear nucleus ; Calyceal processes ; Flattened synaptic vesicles ; Ultrastructure ; Morphometric study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this paper we report the appearance of flat vesicle-containing endings in aldehyde-fixed ventral cochlear nucleus of rats with qualitative and quantitative properties suggesting they should be identified as calyceal processes. Their synaptic vesicles are elongate and significantly smaller than the vesicles in the calyces of Lenn and Reese (1966). Therefore these endings are flat vesicular calyceal processes, possibly of inhibitory function.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 129
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 199 (1979), S. 249-256 
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Birds ; Ultrastructure ; Estrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Administration of estradiol-17-β induces the synthesis of vitellogenin in primary cultures of chick embryo liver. The ultrastructural changes accompanying steroid induced vitellogenin synthesis were investigated in hepatocytes cultures incubated for 0, 12 and 24 h following hormonal treatment. Both electron microscopy and immuno-chemical techniques were used. The immuno-fluorescence data indicate that the cultures contain a cell population of 90–95% hepatocytes, both in control and estradiol-treated groups. Ultrastructurally, cultured hepatocytes are similar to in vivo ones, except for a reduced accumulation of storage materials, glycogen and lipids. In the estradiol-treated cultures hepatocytes show an accumulation of free ribosomes, enlargement of rough endoplasmic reticulum, and development of the Golgi apparatus. The data are discussed in relation to previous biochemical findings.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 130
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 199 (1979), S. 483-492 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; Luteotroph cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars distalis of the rat. The animals received 100μg/100 g pimozide daily for 5, 10, 15, and 20 days. Pimozide induces striking ultrastructural changes after 5 days of treatment. The number of luteotroph (LTH) cells is significantly increased; they display characteristics of stimulation. The extrusion of granules into the intercellular space via exocytosis is frequently observed. The intercellular spaces are highly dilated, forming a lacunar system filled with an amorphous material, erythrocytes and involuted LTH cells. Transitional stages in the process of involution are observed in LTH cells. Luteotroph cells also form a syncytium. Twenty days after treatment the abovedescribed changes decrease in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in the luteotroph cells, an effect that is less evident with longer treatment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 131
    ISSN: 1615-6102
    Keywords: Ciliata ; Crystals ; Euplotes ; Lithosomes ; Microanalysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the cytoplasm of the marine ciliateEuplotes vannus, there exist two conspicuous types of membrane bound inclusions: 1. irregularly shaped crystals which are highly anisotropic; 2. globular lithosomes characterized by concentrically arranged layers of deposits which exhibit only faint birefringence. Normally, both structures form distinct accumulations. Energy dispersive X-ray microanalysis of these accumulations reveals a high content of calcium and phosphorus, besides magnesium, sulphur and chlorine. Analysis of cell areas devoid of the inclusions show significantly lower calcium- and phosphorus-peaks.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 132
    ISSN: 1615-6102
    Keywords: Mating ; Sporidia ; Tilletia ; Ultrastructure ; Wheat bunt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Primary sporidia ofTilletia caries (DC.) Tul. are borne on denticles at the tips of promycelia. The promycelia contain many small vacuoles and mitochondria and numerous lipid bodies. As the primary sporidia develop, the promycelial cytoplasm passes into the nascent cells. Septa develop between the bases of mature sporidia and the tips of the denticles. Sporidia that abscise from the denticles commonly have prominent birth scars at their bases. The sporidia have very thin walls, few vacuoles, attenuated mitochondria, and numerous lipid bodies. Conjugation pegs are generally produced by both members of a conjugating pair of sporidia and there are bud scars where they emerge from the sporidia. The sporidial walls are apparently hydrolyzed during emergence of the pegs. Vesicles are sometimes present at the tips of the conjugation pegs and, before fusion, electron-dense accumulations are sometimes observed between the tips of adjacent pegs. The approaching conjugation pegs are precisely aligned prior to fusion, suggesting polar communication. The walls of the conjugation pegs fuse and then are hydrolyzed. Fused sporidia are relatively homogeneous in content. The nucleus in a sporidum is often close to the conjugation tube and occasionally is partly within the fusion tube.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 133
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 196 (1979), S. 289-306 
    ISSN: 1432-0878
    Keywords: Spleen ; Carp ; Sheathed capillaries ; Macrophages ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the spleen of the carp arterial capillaries of a highly differentiated structure have been studied by light and electron microscopy. These capillaries share various structural characteristics with the sheathed capillaries (ellipsoids of Schweigger-Seidel) of higher vertebrates. The long arterial capillaries of the carp spleen are provided with cuboidal endothelial cells containing filaments approximately 7 nm in diameter. There is no basal lamina. The endothelial cells form various types of cell junctions, but there are also extensive areas without any junctions. Here, a free passage is possible between the capillary lumen and the subendothelial space. The capillaries possess a single-layered sheath of macrophages. Characteristically, the sheath macrophages possess long and slender cell processes forming a loose framework, the meshes of which are filled with lymphocytes and spindle cells. The sheath macrophages show a zone of ectoplasm rich in filaments. They also contain numerous phagolysosomes rich in hydrolytic enzymes, as identified histochemically. The sheath is sharply limited against the pulp by a thick layer of collagen fibers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 134
    ISSN: 1432-0878
    Keywords: Adrenal medulla (rat) ; Vinblastine ; Ultrastructure ; Catecholamines ; Enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a single high dose (10mg/kg) of vinblastine (vb) sulfate (“Velbe”, Lilly) on the ultrastructure, catecholamine (CA) content and activity of CA-synthesizing enzymes of the rat adrenal medulla were studied for up to 120h after intravenous injection of the drug. By 1 h, microtubules were virtually absent from chromaffin cells and preganglionic cholinergic axons, and typical paracrystals had appeared inside the nerve fibers. By 16h microtubules were completely reconstituted and paracrystals had disappeared. From 16h onwards, there was an increasing depletion of storage granules from adrenaline (A) — producing cells, which coincided with biochemical determinations showing a reduction of adrenal A to about 40 % of control levels by 48 h, with noradrenaline (NA) remaining in the range of controls. Both A- and NA-storing cells showed an extensive proliferation of the rough endoplasmic reticulum (ER). Vb caused a marked increase in tyrosine hydroxylase (TH; +113%) and dopamine β-hydroxylase (DBH; +82%) activities after 48 h. Splanchnicotomy completely abolished the vb-mediated increase in TH and DBH activities. A smaller increase (+ 47 %) in enzyme activity was observed with phenylethanolamine N-methyltransferase (PNMT). Vb (10−5M) had no apparent effect on granule content and the amount of rough ER in chromaffin cells, which were cultured for 48 h. The results demonstrate that a single high dose of vb has relatively little short-term effects on the rat adrenal medulla, but causes drastic long-term changes in CA-content and enzyme activities that are mediated by the preganglionic nerves. These changes could be interpreted as an effort to compensate for a loss of CA-stores in peripheral adrenergic nerves (cf. Cheney et al., 1973). The differential long-term effect of vb on adrenal NA and A might be due to the lower induction of PNMT as compared to TH and DBH activities and/or to a preferential release of A versus NA, which may occur at high frequencies of stimulation of the splanchnic nerves.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 135
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Zona fasciculata ; Ultrastructure ; Stereology ; β 1–24-corticotropin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult rats were given 15 daily subcutaneous injections either of synthetic β 1–24-corticotropin or of the corresponding placebo (controls) and were sacrificed 1 h after the final injection. In stimulated animals, the adrenal glands were increased in weight as compared to those of controls. Stereological analysis at light microscopic level of the outer zona fasciculata cells showed moderate volumetric increases of nuclei, cytoplasm and capillaries and a marked volumetric increase of lipid droplets in stimulated animals. Stereologic analysis of electron micrographs confirmed the marked increase in relative volume and surface density of lipid droplets, while volume fractions alone were increased for the Golgi apparatus and decreased for the endoplasmic reticulum and mitochondria. Biochemical analysis of the whole adrenal gland showed that the corticotropin injections produced a moderate increase in protein concentration, a marked increase in triglycerides and no appreciable changes in either phospholipid or cholesterol concentrations. The synthetic polypeptide therefore appears to have stimulating trophic effects on adrenal cortical cells, as shown by the increase in protein and cell size. However, it depresses the activity of the two types of organelle, endoplasmic reticulum and mitochondria, which have a major functional role in steroid synthesis. The increase of lipid droplets was interpreted as being primarily due to neutral fat accumulation, and secondarily to a diminished utilization of cholesterol for steroid synthesis. These findings suggest that, using this regime of administration, synthetic β 1–24 corticotropin, unlike native ACTH, inhibits steroid synthesis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 136
    ISSN: 1432-0878
    Keywords: HRP injection ; Lymnaea Stagnalis ; Neurohaemal areas ; Neurosecretory cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired, electrotonically coupled neurosecretory Canopy Cells (CC) of the pond snail Lymnaea stagnalis were microiontophoretically injected with horseradish peroxidase (HRP). Whole mount preparations and ultrathin sections of injected CC were studied to describe in detail the morphology of the CC, their axon tracts and neurohaemal areas. The CC release their secretory product at three different sites, viz. from the soma and from axon terminals in the intercerebral commissure and in the median lip nerve. Neural control over the CC occurs by few synapses found exclusively on the CC axon, not on the cell body. One type of “en passant” synapse was identified. Two morphologically distinct types of synapselike structures (SLS) are numerous. The site of electrotonic coupling between the two CC is most probably located in the cerebral commissure. Serial sectioning showed that the axons contact each other over more than 130 μm. The contact is very intimate and the axon membranes interdigitate in a complex manner. Gap junctions, which are often described as the sites of electrotonic coupling, were not found.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 137
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 202 (1979), S. 431-438 
    ISSN: 1432-0878
    Keywords: Sturgeon ; Heart ; Ultrastructure ; Sarcoplasmic reticulum ; Granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of atrial and ventricular myocardial cells from Acipenser stellatus is described. The cells of the atrium are more loosely connected than those of the ventricle. Cell contact is by simple intercalated discs and by desmosomes. The cells are flattened, with peripheral myofibrils and a central region of mitochondria and the nucleus. The sarcoplasmic reticulum consists of subsarcolemmal tubules, that frequently extend towards the central mitochondria. Dyads are small and positioned at any sarcomeric level. No T-tubules are present. Specific granules are restricted to the atrial cell, and are sometimes present within the SR tubules.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 138
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 377 (1978), S. 157-174 
    ISSN: 1432-2307
    Keywords: Pancreatic diabetes ; Endocrine pancreas ; Islet composition ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The endocrine pancreatic tissue from patients with severe primary chronic pancreatitis (n=6), secondary chronic pancreatitis due to duct obstruction by carcinoma (n=6) and non-diabetic, non-pancreatitic controls (n=4) was studied qualitatively and quantitatively using specific immunocytochemistry and electron microscopy. Grouping of variously sized islets in the sclerotic tissue (sclerosis islets), islet neoformation by ductuloinsular proliferation, and intrainsular fibrosis were the main qualitative findings. Immunocytochemical quantitation of the distribution of insulin (B), glucagon (A), somatostatin (D) and pancreatic polypeptide (PP) producing cells revealed a significant relative increase in the number of A cells and a decrease in the number of B cells of the sclerosis islets in primary chronic pancreatitis (B-44.1±9.3%:A-38.3±2.4%:D-8.6±5.1%:PP-4.6±4.1%) as well as in secondary chronic pancreatitis (B-38.0±14.3%:A-38.4±19.0%:D-9.1±5.8%:PP-14.5±23.4%) compared with controls (B-71.1±8.1%:A-24.3±5.5%:D-8.0±2.8%:PP-0.5±0.4%). The number of PP cells was significantly increased in primary chronic pancreatitis only. It is suggested that scarring of the exocrine pancreas affects islet composition, probably by impairment of the local circulation and of glucose diffusion, thus leading to reduction of the number and glucose sensitivity of B cells. The hyperplasia of A and PP cells appears to be a secondary phenomenon due to the loss of B cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 139
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 378 (1978), S. 161-172 
    ISSN: 1432-2307
    Keywords: Chemodectoma ; Larynx ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present case report is concerned with a clinico-pathological study, including ultrastructural investigation, of a rare and uncommon laryngeal tumour, a chemodectoma, in a 62 year old patient. There have been 23 cases of laryngeal chemodectomas reported in the literature, and only three of them, including our own report, were investigated by electron microscopy. The tumours arise from the superior and inferior laryngeal nonchromaffin paraganglia or possibly from Kultschitzky-cells of the normal bronchial mucosa. Ultrastructurally they have all the characteristics of apudomas whose parent cells (the APUD-cells), usually show endocrine function and probably have their origin in the neural crest. The tumours show an aggressive type of behaviour, despite usually benign histological features when compared to chemodectomas at other sites in the head and neck region. Surgery is thus the therapy of choice.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 140
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 379 (1978), S. 321-333 
    ISSN: 1432-2307
    Keywords: Pinguecula ; Pterygium ; Histology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two pingueculae combined with pterygia were studied by light and electron microscopy. Hyaline degeneration of the collagen, dark staining granular, von Kossa negative concretions and elastotic material were observed in both conditions together with marked changes in the fibroblasts, endothelial cells, pericytes and the basement membrane of conjunctival capillaries and small veins. The elastotic material is similar to that observed in solar elastosis, where the collagen fibers are less severely damaged. Chronic sun exposure of the pericorneal conjunctiva may damage endothelial cells primarily and disturb vascular exchanges. This would result in accelerated degeneration and regeneration of endothelial cells, in thickening of the basement membrane and, secondarily, disturbed metabolism of fibroblasts with alterations of the collagen and elastic fibers.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 141
    ISSN: 1432-2307
    Keywords: Thyroid ; Adenoma ; Ultrastructure ; Immunhistochemistry ; Thyroglobulin ; Lysosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histological, immunhistochemical and electronmicroscopic studies of 12 human, scintigraphically “cold”, thyroid adenomas with specific cytological differentiation identified four different cell types: oxiphil cell, clear cell, ergastoplasm-rich cell and mitochondrion-rich cell. The oxiphil tumor cell can be recognized light-microscopically by its large size and its eosinophilic granular cytoplasm. Most of these cells do not produce thyroglobulin. The ultrastructural characteristics of oxyphil cells are principally mitochondria in great numbers and many large lysosomes. Clear cell adenomas show a trabecular growth pattern. The tumor cells have an abundance of cytoplasm which contains small acidophilic granules. Immunhistochemically we were able to demonstrate thyroglobulin in small amounts within cytoplasmic granules and more extensively within the follicle lumina. Electronmicroscopically we observed a large number of smooth surfaced vacuoles of varying size, extraordinary large lysosomes and occasional cisternae of rough endoplasmic reticulum, the latter probably corresponding to the immune-histochemically identified thyroglobulin granules. The ergastoplasm-rich-cell adenomas, which to the best of our knowledge have not been previously described, show a predominantly micro-to normofollicular architecture histologically without intrafollicular colloid. The cytoplasm of the ergastoplasm-rich cells reveales a strong positive thyroglobulin-staining reaction. The fine structure of these cells is characterized by the abundance of cisternae of the rough endoplasmic reticulum. The mitochondrion-rich-cell adenomas exhibited a microfollicular structure with an intensive acidophilic granular staining at the basal part of the tumor cells. Immunhistochemically and electronmicroscopically we found some morphologic and functional features which differentiate these cells from the oxyphil cell. Thyroglobulin was located predominantly in the apical portion of the cytoplasm in the mitochondrion-rich cells without sharp demarcation from the luminar thyroglobulin. Electron microscopically fewer basal and laterally located mitochondria were seen in mitochondrion-rich cells compared with oxyphil cells. As we could not find any sign of functional activity in the oxyphilic, clear cell and ergastoplasm-rich cell adenomas we analysed those aspects of the lysosomal system not concerned with the enzymatic digestion of thyroglobulin.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 142
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 91 (1978), S. 165-182 
    ISSN: 1432-1335
    Keywords: Clear cells ; Salivary gland tumors ; Ultrastructure ; Differential diagnosis ; Helle Zellen ; Speicheldrüsentumoren ; Ultrastruktur ; Differentialdiagnose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zu den hellzelligen Speicheldrüsentumoren gehören monomorphe hellzellige Adenome, hellzellige Carcinome, hellzellige Varianten der Acinus- und Mucoepidermoidtumoren, Talgdrüsentumoren, Speichelgang-Carcinome und pleomorphe Adenome mit hellzelligen Abschnitten. Der lichtmikroskopische, deskriptive Begriff der hellen Zelle umfaßt bei einer weiteren cytochemischen und elektronenmikroskopischen Analyse Zellformen unterschiedlicher Herkunft und funktioneller Bedeutung. Folgende Zelltypen wurden näher analysiert: indifferente Gangzellen (geringe Organellenausbildung, Desmosomen), speichernde Streifenstückzellen (Glykogengranula, zahlreiche Mitochondrien, basales Labyrinth), Myoepithelzellen (Myofilamente, Pinocytose-Vesicel, Lipofuscingranula, Hemidesmosomen), epidermoide Zellen (Tonofilamente, Desmosomen), Becherzellen (Schleimvacuolen, basales endoplasmatisches Reticulum), Talgdrüsenzellen (Lipidtropfen, Mikrovilli, Desmosomen) und helle Acinuszellen (elektronenoptisch helle Sekretgranula, kleine Mitochondrien, kleiner Golgiapparat). In die Differentialdiagnose müssen auch hellzellige Tumorformen der Speicheldrüsenregion einbezogen werden, welche primär nicht vom Speicheldrüsengewebe ausgehen. Hierzu gehören Metastasen hypernephroider Nieren-Carcinome, Paragangliome, Glomustumoren Masson, Granularzelltumoren und alveoläre Weichteilsarkome.
    Notes: Summary Clear cell tumors of the salivary glands are monomorphic clear cell adenomas, clear cell carcinomas, clear cell variants of acinic cell and mucoepidermoid tumours, sebaceous cell tumors, salivary duct carcinomas and pleomorphic adenomas with clear cell sectors. At the light microscopical level the descriptive term of the clear cell comprises cell types of different origin and functional importance which can be differentiated by cytochemistry and electron microscopy. The following cell types were analysed precisely: indifferent duct cells (small formation of organelles, desmosomes), storing striated duct cells (glycogen granules, multiple mitochondrias, basal labyrinth), myoepithelial cells (myofilaments, pinocytosis vesicles, lipofuscin granules, hemidesmosomes), goblet cells (mucous vacuoles, basal endoplasmatic reticulum), sebaceous cells (lipid droplets, microvilli, desmosomes) and clear acinic cells (electron pale secretory granules, small mitochondrias, small golgi apparatus). Clear cell tumor types of the salivary gland region which primarely do not derive from the salivary gland tissue must also be included in the differential diagnoses. These are metastases of hypernephroid renal carcinomas, paragangliomas, glomus tumors of Masson, granular cell tumor and alveolar soft-part sarcomas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 143
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 379 (1978), S. 185-201 
    ISSN: 1432-2307
    Keywords: Giant cell tumor ; Ultrastructure ; Acid phosphatase ; Lysosomes ; Bone tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of the different cell types constituting a primary malignant giant cell tumor of bone has been studied and the localization of acid phosphatase in relation to the subcellular organelles been demonstrated. Three distinct cell types with characteristic ultrastructural features were observed: giant cells, fibroblast-like cells, and cells with abundant lipid inclusions and mitochondria. Certain differences were noted between these three cell types and their counterparts in benign giant cell tumors of bone (described in a separate report). The enzyme histochemical and morphological data suggested that the giant cells in the malignant tumor might possess a more active and expansive lysosomal apparatus than corresponding cells in the benign variant.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 144
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 379 (1978), S. 229-241 
    ISSN: 1432-2307
    Keywords: Placenta ; Ultrastructure ; Rhesus incompatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electronoptical study has been made of eleven placentae from cases of materno-fetal rhesus incompatibility. The characteristic findings are focal, but sometimes quite extensive, syncytial necrosis, retention of normal pinocytotic and secretory activity in the non-necrotic syncytiotrophoblast, cytotrophoblastic hyperplasia, thickening of the trophoblastic basement membrane, immature-type endothelial cells in the fetal villous vessels and thickening or lamination of the capillary basement membranes. The pathogenesis of many of these changes is not clear but there is no evidence that they are immunologically mediated. It is suggested that the syncytial necrosis may be due to narrowing of the intervillous space as a result of increased villous size, that the cytotrophoblastic hyperplasia is a response to the syncytial damage and is responsible for the changes in the trophoblastic basement membrane and that the fetal capillary changes are indicative of endothelial cell damage due, possibly, to fetal anaemia. Despite the damage suffered by the placenta in materno-fetal rhesus incompatibility there is little evidence of impaired functional efficiency.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 145
    ISSN: 1432-2307
    Keywords: Pitutary ; Ultrastructure ; Vasopressin ; Prostaglandin ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ziel dieser Untersuchung war es, quantitative and qualitative Änderungen der ACTH-Zelle in der Rattenhypophyse nach Gabe eines spezifischen und eines unspezifischen Stimulus zu untersuchen. Es wurden ein CRF-Analogon (Lysin-Vasopressin) und ein Prostaglandin (Prostaglandin E1) benutzt. Jeweils 20 Ratten wurden für 4 Wochen Lysin-Vasopressin oder Prostaglandin E1 intraperitoneal injiziert. Die Hypophysen wurden licht- und elektronenoptisch sowie morphometrisch untersucht. Nach Gabe beider Stoffe konnte man eine Aktivierung der ACTH-Zellen beobachten. Die Vergrö\erung des Kerns, des Cytoplasmas und der an der Hormonherstellung beteiligten Zellorganellen lie\ sich morphometrisch nachweisen, wobei die Wirkung von Lysin-Vasopressin ausgeprÄgter war als die des Prostaglandins. Darüber hinaus konnte eine Zunahme der ACTH-Zellzahl gefunden und mit einem statistischen Test als signifikant nachgewiesen werden. Im Gegensatz zu Lysin-Vasopressin erstreckte sich die Wirkung des Prostaglandins auch auf andere Hypophysenzellen.
    Notes: Summary The aim of this study was to investigate the qualitative and quantitative changes of ACTH-cells in the rat after application of a specific and a non-specific stimulus. A CRF-analog (lysin-vasopressin) and a prostaglandin (prostaglandin E1) were used. 40 rats were injected lysin-vasopressin or prostaglandin E1, respectively, for 4 weeks. The pituitary glands were investigated by means of light microscopy, electron microscopy and morphometry. Activation of the ACTH-cells could be observed after use of both substances, the effect of lysin-vasopressin being more intense than that of prostaglandin E1. Enlargement of the nucleus, the cytoplasm and the organelles involved in hormone-production and -transport were found and verified by morphometry. Additionally an increase in number of the cells could be demonstrated. Prostaglandin influenced not only ACTH-cells, but also other cells of the anterior pituitary.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 146
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 378 (1978), S. 287-295 
    ISSN: 1432-2307
    Keywords: Giant cell tumor ; Ultrastructure ; Alkaline phosphatase ; Human bone neoplasias
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structural localization of nonspecific alkaline phosphatase was elucidated in two giant cell tumors of bone using lead as capturing ion and Β-glycerophosphate as substrate in the incubation solution. Lead phosphate precipitate — indicating presence of alkaline phosphatase — was demonstrated on the plasma membranes, and the membranes bordering vesicles and vacuoles of presumed endocytotic nature, in giant cells and type 1 stromal cells (fibroblast-like cells). The findings support the view that stromal cells type I and giant cells are histogenetically related.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 147
    ISSN: 1432-2307
    Keywords: Primary hyperparathyroidism ; Bone cells ; Bone matrix ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electron microscope investigation has been carried out on needle biopsies of the iliac crest of 8 patients suffering from primary hyperparathyroidism. A marked increase in bone resorption was the most conspicuous finding. It was due both to increased osteoclastic activity and to periosteocytic osteolysis. The osteoclasts had a more strongly developed brush border and contained more cytoplasmic vacuoles than those in controls. Many osteocytes were found within enlarged, irregular lacunae, and were surrounded by a space containing amorphous, granular and filamentous material. Their mitochondria were sometimes calcified. Osteoblasts were more active than in controls as shown by the developed rough ergastoplasmic cysternae and thick osteoid borders found near some of them. The osteoid tissue, however, was uncalcified; ultrastructurally, lack of the calcification front and incomplete matrix calcification were demonstrable. Mast cells, and osteoclast- and macrophage-like giant cells were often found in the fibrotic marrow spaces. These results confirm that both the resorption and the formation of bone are stimulated in hyperparathyroidism. The calcification process is delayed and often remains incomplete.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 148
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 380 (1978), S. 59-79 
    ISSN: 1432-2307
    Keywords: Cerebellar astrocytoma ; Optic glioma ; Pilocytic astrocytoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural comparison of 8 cerebellar astrocytomas and 4 optic gliomas shows that the morphological patterns of both tumor-groups are identical. The confusion in nomenclature of these tumors is discussed and reasons for a preference for the term “pilocytic astrocytomas” are given. Further, pilocytic astrocytes seem to be a special, phylogenetically older, group of glial cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 149
    ISSN: 1432-0827
    Keywords: Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 150
    ISSN: 1432-0738
    Keywords: Mercury ; Selenium ; Retention ; Liver ; Kidney ; Ultrastructure ; Interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Distribution and retention of mercury and selenium was studied in rats exposed repeatedly to HgCl2 injections (0.5 mg Hg/kg to the tail vein every other day) and intragastrically to Na2SeO3 (0.5 mg Se/kg every day), applying combined and separate administration of these metals for 2 weeks. Whole-body retention of mercury in the presence of selenium was augmented by 20% and that of selenium in the presence of mercury by 4% with respect to the administered dose. Combined administration of mercuric chloride and sodium selenite brought about damage to the epithelial cells of renal proximal convolutions and formation of protein casts in their lumen. These changes had the same pattern as those induced by administration of mercuric chloride alone, but the intensity was lower. Submicroscopic studies revealed that repeated combined administration of sodium selenite and mercuric chloride did not completely abolish the mercury-induced mitochondrial swelling and contributed to chromatin destruction in the hepatocyte nuclei.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 151
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 261 (1978), S. 231-244 
    ISSN: 1432-069X
    Keywords: Colloid Milium ; Different types ; Histopathology ; Ultrastructure ; Colloid Milium ; Verschiedene Typen ; Histopathologie ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Unterschiede im Verlauf und Erbmuster des Colloid Milium deuten an, daß zwischen dem juvenilen und adulten Typ dieser Dermatose wesentliche Unterschiede bestehen. Ziel der vorliegenden Untersuchungen war, mit Hilfe von Licht-, Immunfluorescenz- und elektronenoptischen Methoden nach Unterschieden im mikroskopischen Bereich anhand je eines Falles zu suchen. Folgende Befunde wurden erhoben: Beim juvenilen Colloid Milium sind die Kolloidmassen nicht nur direkt unter dem Epithel abgelagert, sondern auch innerhalb der Epidermis häufig zu finden. Sie zeigen nach Kongorotfärbung einen Dichroismus und können Immunglobuline, Komplement und Fibrin enthalten. Elektronenmikroskopisch zeigt sich, daß sie aus dicht gepackten wellig verlaufenden Fibrillen bestehen, deren individueller Durchmesser etwa 80 Å beträgt. Innerhalb dieser fibrillären Massen sind häufig Melanosomen, Reste von Kernen und anderen Zellorganellen sowie Desmosomen nachweisbar. Beim adulten Colloid Milium sind die Kolloidmassen meist von der Epidermis durch einen Elastika-positiven Bindegewebsstreifen getrennt. Mit Kongorot sind sie nur schwach darstellbar und zeigen keinen Dichroismus. Fluorescenzoptisch zeigen sie eine bläuliche Autofluorescenz, aber keine spezifischen Ablagerungen. Elektronenmikroskopisch kann das adulte Kolloid als feingranuläres Material mit wenigen feinsten Mikrofibrillen charakterisiert werden, das in enger Nachbarschaft von Gefäßen mit verdichteter Basalmembran und von aktiven Fibroblasten gelegen ist. Auf Grund dieser Unterschiede können der juvenile und adulte Typ des Colloid Miliums klar auch mikroskopisch voneinander differenziert werden. Die Ergebnisse deuten darauf hin, daß beim juvenilen Typ vorwiegend epidermale Läsionen, beim adulten jedoch dermale Störungen eine wesentliche Rolle in der Pathogenese spielen.
    Notes: Summary Two different types of colloid milium are characterized on the basis of clinical and genetical parameters. In order to establish morphological criteria allowing a differentiation also at microscopic levels comparative histopathological, histo- and immunochemical as well as ultrastructural investigations were performed in a case of juvenile and a case of adult colloid milium. The following results were obtained: In juvenile colloid milium the colloid material is deposed in direct apposition to the basal epidermal layers and can be found also in suprabasal position within the epidermis. No actinic elastosis is present in the periphery of the deposits but they exhibit a green birefringency by investigation of Congo-red stained frozen sections in polarized light. Immunoglobulins, complement and fibrin can be demonstrated within the deposits by direct immunofluorescence. Electron microscopy reveales a fibrillar ultrastructure of the colloid masses, which contain numerous melanin granules and desmosomes. Therefore the colloid material in the juvenile type is most likely of epidermal origin. In adult colloid milium the colloid is usually separated from the epidermis by a band of connective tissue elements containing a considerable amount of elastin. The surrounding superficial dermis frequently exhibits elastotic changes. Congo-red reaction is only weakly positive and no dichroisms can be found. Direct immunofluorescence reveals no specific staining, but a blue autofluorescence of the material. Ultrastructurally, the adult colloid represents mainly finely granular material, with only few microfilaments. The masses are situated in the dermis, often near duplicated vascular basement membranes and in close apposition to active fibroblasts. Thus, the colloid material seems to be of dermal origin. The microscopic findings strongly indicate, that the two different types of colloid milium indeed represent different entities, discernable not only by clinical or genetic but also by histomorphologic parameters.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 152
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 262 (1978), S. 219-227 
    ISSN: 1432-069X
    Keywords: Nude mice ; Skin pigmentation ; Ultrastructure ; Tyrosinase activity ; Hair cycle ; Nackte Mäuse ; Hautpigmentierung ; Ultrastruktur ; Tyrosinaseaktivität ; Haarcyclus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Autoren untersuchten die Pigmentveränderungen an Haut und Haar an pigmentierten nackten Mäusen. Histologische und elektronenmikroskopische Untersuchungen und die Polyacrylamid-Elektrophorese der Tyrosinaseaktivitäten zeigten vom morphologischen und biochemischen, daß die Veränderungen der Programmierung solcher “nude” Mäuse auf den Haarcyclus und auf das Haarwachstum bezogen werden kann. In der Tat entwickeln sich die Haarfollikel cyclisch wie die der Mäuse mit normaler Haut. In depigmentierter Haut waren die Haare in der Ruhepause und es konnte keine lösliche Tyrosinase aufgefunden werden.
    Notes: Summary The authors have studied pigmentary changes of skin and hair due to the presence of the “nude” gene in pigmented species (C 57 Bl. 6J, C 3H). Morphological (histology, electron microscopy) and biochemical (polyacrylamide gel electrophoresis of tyrosinase activities) studies showed that the pigmentary alterations of the “nude” mice were related to the hair cycle and hair growth wave pattern. In fact, in the “nude” mice the hair follicles evolves cyclically similarly to mice of normal coat. In depigmented skin, the hair follicles were in the resting phase and no soluble tyrosinase could be demonstrated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 153
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 263 (1978), S. 159-169 
    ISSN: 1432-069X
    Keywords: Leiomyosarcoma of the skin ; Ultrastructure ; Cellular differentiation ; Accumulation of centrioles ; Cutanes Leiomyosarkom ; Ultrastruktur ; celluläre Differenzierung ; multiple Centriolen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine 61jährige Patientin hatte sich vor 15 Jahren einen Tumor vom linken Unterschenkel entfernen lassen. Im Bereich der Narbe kam es zu erneuter Tumorbildung. Die histologische Untersuchung zeigte einen aus meist spindeligen Zellen zusammengesetzten Tumor mit vielen Mitosen und Kernpolymorphie. Die Diagnose eines cutanen Leiomyosarkoms wurde durch den elektronenmikroskopischen Nachweis der für glatte Muskelzellen charakteristischen Zellelemente gesichert. Der Differenzierungsgrad der Tumorzellen variierte zwischen relativ differenzierten, filamentreichen Zellen, die noch an normale glatte Muskelzellen erinnerten, und ödematösen, filamentarmen, aber organellenreichen entdifferenzierten Zellen. Eine auffallende morphologische Besonderheit war der wiederholte Nachweis von zahlreichen akkumulierten Centriolen.
    Notes: Summary A 61-year old woman developed a tumourous nodule in her left leg. Fifteen years ago a similar tumour had been removed in the same localization. Histological examination performed on biopsy material showed bundles of predominantly fusiform tumour cells with nuclear pleomorphism and many mitotic figures. Electron microscopic examination confirmed the diagnosis of leiomyosarcoma by demonstration of the ultrastructural characteristics of smooth muscle cells. Cellular differentiation showed various degree ranging from smooth muscle cell type to dedifferentiated edematous tumour cells with scanty myofilaments. An important finding was the demonstration of multiple accumulated centrioles.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 154
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 263 (1978), S. 153-157 
    ISSN: 1432-069X
    Keywords: Chancroids ; Biopsies ; Haemophilus ducreyi ; Ultrastructure ; Ulcera mollia ; Biopsien ; Haemophilus ducreyi ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Anläßlich einer lokalen Häufung von insgesamt 26 Ulcus molle-Fällen in Berlin (West) wurden in Biopsien coccoide Stäbchen durch ultrastrukturelle Untersuchung entdeckt. Ihre Zellwand ist ca. 120 Å dick und trilaminar entsprechend Gram-negativen Bakterien. Die Bakterien sind hinsichtlich der Zellwandstruktur sowie der Cytoplasmazusammensetzung identisch mit Haemophilus ducreyi, die kulturell von typischen Ulcera mollia gezüchtet, intermittierend mikroskopisch auf Reinheit geprüft, in tierisches Material geimpft und anschließend ultrastrukturell untersucht wurden. In menschlichem ulcerösen Gewebe finden sich die Bakterien überwiegend im Extracellulärraum und in Gruppen gelagert.
    Notes: Summary During an endemic appearance of chancroids (26 cases) in Berlin (West) coccobacilli were disclosed in biopsies by electron microscopy. The bacteria were aggregated predominantly in groups in the extracellular space. Their cell wall is approximately 120 Å thick and trilaminar as in Gram-negative bacteria. Concerning the cell wall structure and the cytoplasmic composition, the detected coccobacilli are identical to culturally grown Haemophilus ducreyi obtained from chancroids.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 155
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 154 (1978), S. 1-25 
    ISSN: 1432-0568
    Keywords: Bile canaliculus ; Development ; Glycogenesis ; Hepatocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural changes during development and metamorphosis in the liver ofXenopus laevis have been investigated. In this species it was found that developmental processes, which ultimately lead to the formation of bile canaliculi, can be detected in the liver anlage as early as stage 35. While the wall of the primary liver cavity is thrown into folds which form the liver parenchyma, the bile canaliculi are formed (st. 36–38). Secretion into the lumen of the bile canaliculi was not found to occur before stage 47 and IDP-ase activity could not be detected in the bile canaliculi before stage 49. The intra- and extrahepatic portions of the hepatic duct system were found to be formed during the stages 40–41. The formation of the duct system involves cellular degeneration in the lumen of the future ducts. These processes are described in detail. The glycogen content of the developing hepatocytes received particular attention during the course of this study. It was found that after depletion of the embryonal glycogen the hepatocytes are completely free from glycogen during the stages 43–45. At stage 46, after the begin of feeding, beta as well as alpha particles of glycogen appear in the hepatocytes. These first reappearing glycogen particles are formed without the participation of SER membranes, in areas which are loaded with RNA particles. It was found that only after the synthesis of glycogen had been initiated SER membranes started to proliferate in the hepatocytes, where they were mostly found intermingled with glycogen particles. From stage 54 on, where the liver glycogen content was found to be 0.2%, the glycogen content of the liver almost continuously increased until it reached a temporary peak of 10% at the end of metamorphosis. These findings strongly contrast results reported for other amphibia, which at the end of metamorphosis have depleted their glycogen content completely. Details of the ultrastructural changes occuring during development of the hepatocytes, are also reported in this paper.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 156
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 154 (1978), S. 67-82 
    ISSN: 1432-0568
    Keywords: Urodeles ; Spinal cord ; Ependyma ; Glia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The structural organization of the ependymal and macroglial components of the central field of the spinal cord of postmetamorphic ribbed newts has been reinvestigated using elaborate fixation procedures for transmission electron microscopy. All along the central canal, the ependymal cells display ultrastructural features that strongly suggest a secretory activity. Infrequent mitotic images, occurring spontaneously among the ependymal cells, were observed. The tightly compacted periependymal stratum contains two types of glial cells: 1. oligodendrocytes, also observed outside this stratum as neuronal satellites, and 2. radial astrocytic cells, whose somata, exclusively located in the periependymal stratum, send their processes to the subpial lamina. The intercellular relationships between ependyma, oligodendrocytes and astrocytic cells are illustrated to show the continuity of the neuroepithelial configuration. Morphologic clues for identifying the cells of the central field of the urodele spinal cord are given. A gradient of differentiation of the oligodendroglial components could be postulated. In normal conditions, the astroglial differentiation is permanently arrested at the stage of radial glia. Some considerations concerning regeneration in the urodele spinal cord are submitted.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 157
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 154 (1978), S. 185-211 
    ISSN: 1432-0568
    Keywords: Adenohypophysis ; Cellular types ; Ultrastructure ; Birds ; Excalfactoria chinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural analysis of the adenohypophysis in the male Chinese quail reveals seven different types of granular cells, and agranular folliculo-stellate cells. The cell types are assumed to be endocrine cells and are classified as: Type I cells (presumptive LH-gonadotrophs), with dilated endoplasmic reticulum, perinuclear spaces, and granules of 150–260 nm; Type II cells (presumptive FSH-gonadotrophs), with regularly-shaped cytoplasmic cisterns and small granules (80–150 nm); Type III cells (presumptive thyrotrophs), very close in appearance to the type II cells of normal birds; Type IV cells (presumptive prolactin cells), with very large secretory granules (up to 400 nm), Type V cells (presumptive corticotrophs), with abundant and electrondense granules (160–300 nm); Type VI cells, with irregularly-shaped granules; Type VII cells (presumptive somatotrophs), with abundant granules (130–220 nm) and less cytoplasmic structures. Cytological characteristics of the nucleus, and more particularly the presence of a Feulgen-positive nucleolus with a very particular ultrastructure are here reported. It is proposed that heterospecific associations of Chinese quail cells with chick cells can be used in embryological work for the study of cellular interactions.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 158
    ISSN: 1432-0533
    Keywords: Tissue cultures ; Cytochalasin B and colchicine ; Cell motility ; Ultrastructure ; Glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Primary tissue cultures of human gliomas were treated with cytochalasin B (0.5–60 μg/ml for 90 min). Cell motility was inhibited irreversibly in glial tumour cells, but the effect was reversible on the mesenchymal cells growing in culture in the lower dose range. Cell adhesion was considerably reduced as the dose was increased, as was the capacity for cells to spread on a surface from suspension. Low concentrations of cytochalasin B caused negligible cell death and little disruption of cell ultrastructure. However, increases in dose were accompanied by a greater predominance of rough endoplasmic reticulum and inclusions and aggregation of microfilament bundles. As seen by scanning electron microscopy, cytochalasin B caused the withdrawal of peripheral cell borders, disappearance of ruffles and the breakdown of cytoplasmic lamellae. Charateristic surface blebs and folds appeared in their place. By comparison, colchicine (1–10 μg/ml) caused a less marked and non-specific reversible reduction in cell motility on both glial and mesenchymal cells. No significant change in cell adhesion or spreading took place even at high doses, although at all concentrations gross disruption of the cell surface took place with changes in ultrastructure characterised by loss of cytoplasmic microtubules and aggregation of 10 nm filaments.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 159
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 185 (1978), S. 235-248 
    ISSN: 1432-041X
    Keywords: Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 160
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    ISSN: 1432-0827
    Keywords: Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 161
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 262 (1978), S. 135-141 
    ISSN: 1432-069X
    Keywords: Pseudolymphoma ; Oriental hornet venom ; Ultrastructure ; Pseudolymphoma ; Orientalische Wespe ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine einmalige sucutane Injektion des Giftes der orientalischen Wespe führt bei schwarzen Mäusen zu der Entwicklung eines subcutanen Knötchens, welches sich über 1 Jahr hält. Ultrastrukturell zeigt sich eine Anreicherung von Lymphocyten und Lymphoblasten und einige Plasmazellen mit Russelkörperchen. Zusätzlich werden einige Melanin enthaltende Makrophagen und auch solche mit aufgenommenen cellulären Abbauprodukten beobachtet. Die gesamte Reaktion wird mit anderen pseudolymphomatösen Reaktionen in der Haut in Beziehung gesetzt.
    Notes: Summary A single subcutaneous injection of Oriental hornet venom into black mice led to the development of a subcutaneous nodule which showed no change during the period of 1 year. Study of the ultrastructure revealed an accumulation of lymphocytes and lymphoblasts and a few plasma cells with formation of Russel bodies. In addition, a few melanin-containing macrophages and macrophages filled with cellular debris were found. This reaction is compared to other pseudolymphomatous reactions in the dermis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 162
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 117 (1978), S. 293-295 
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 163
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 118 (1978), S. 309-316 
    ISSN: 1432-072X
    Keywords: Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 164
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 91 (1978), S. 195-204 
    ISSN: 1432-1335
    Keywords: Hydantoin ; Malignant Lymphoma ; Mice ; Ultrastructure ; Hydantoin ; Maligne Lymphome ; Maus ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ultrastrukturelle Zellveränderungen werden beschrieben am Original-Tumorgewebe und an Tumorzellen aus der Kurzzeitkultur von malignen Lymphomen, induziert durch chronische Diphenylhydantoin-Exposition. Diese Tumoren entstanden in Mäuse-Inzuchtlinien mit niedriger (C57Bl) und hoher (SJL/J) spontaner Lymphomrate im fortgeschrittenen Alter, waren jedoch nicht induzierbar in einer Lymphom-resistenten Linie (C3Hf). Frühveränderungen des lymphoretikulären Gewebes bestanden in einer zunehmenden Atrophie des Thymus und der thymusabhängigen Partien, begleitet von einer diffusen retikulo-histiozytären Hyperplasie. Lymphome vom lymphoblastischen Typ entstanden im Thymus nach einer Latenzzeit von 4–8 Monaten mit nachfolgender Generalisation. Verschiedene atypische Veränderungen wurden an Tumorzellen beobachtet sowie das Auftreten von C-Typ-Partikeln in den Tumorzellkulturen und hinsichtlich der Pathogenese der Lymphome diskutiert.
    Notes: Summary Ultrastructural studies were done on cells from original tumors and from short time cultures of mouse thymic lymphomas experimentally induced by chronic exposure to diphenyl-hydantoin. The tumors appeared in mouse strains with low (C57Bl) and high (SJL/J) susceptibility to spontaneous lymphoma development and were not observed in a resistant strain (C3Hf). Thymic lymphoma development was usually preceded by increasing lymphoreticular atrophy followed by progressive reticulohistiocytic hyperplasia, and subsequently spread to other tissues. Morphologically the tumor was characterized as a lymphoblastic lymphoma. Abnormal cell changes in the original tumors and cultured cells, and the presence of murine C-type particles in the cultured cells but not in the original tumors, are discused in relation with the disturbance of immune system and the lymphoma enhancement produced by diphenyl-hydantoin.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 165
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 116 (1978), S. 279-288 
    ISSN: 1432-072X
    Keywords: Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 166
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 262 (1978), S. 205-217 
    ISSN: 1432-069X
    Keywords: Mycobacterium marinum ; Ultrastructure ; High-turnover granuloma ; Immunogenic orgin ; Intracellular collagen precursor ; Mycobaterium marinum ; Ultrastruktur ; High-turnover Granulom ; Immunogenes Granulom ; Intracelluläre Kollagenpräcursoren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Drei Knoten (klinisches Alter 3–5 Wochen) von 2 Patienten mit sogenannten Swimmingpool- oder Aquariumgranulomen wurden elektronenoptisch untersucht. Das cytohistologische Spektrum umfaßt sowohl akute exsudative, als auch chronische proliferative Entzündungszeichen. Bereits im 3 Wochen alten Granulom sind Epitheloidzellen und Kollagen produzierende Fibroblasten nachweisbar. Das Mycobacterium marinum-Granulom stellt gemäß dem cytologischen Aufbau ein sog. High-turnover Granulom mit allergischer Genese dar. Es entspricht damit mycobacteriellen Dermatosen bei bestehender guter Abwehrlage (Lupus vulgaris, tuberkuloide Lepra). In Abbau befindliche Mycobacterien konnten in wenigen Phagocyten entdeckt werden. Die Ultrastruktur des lebenden Erregers wird vergleichsweise von tierexperimentellem Material präsentiert. Geschwungene und ringförmige parallele Membranen (“Worm-like structures”) wurden im Cytoplasma von transformierten Makrophagen und in Fibroblasten beobachtet. Fadenförmige quergebänderte Strukturen (Periodizität 170–180 Å) im Lumen des rauhen endoplasmatischen Reticulums von einigen Fibroblasten werden als intracellulär aggregierte Kollagenpräcursoren interpretiert.
    Notes: Summary 3 biopsies of 3–5 week-old nodular lesions in 2 patients with socalled swimming-pool (aquarium-) granuloma have been examined by electron microscopy. The cytohistological spectrum simultaneously comprises acute exudative as well as chronic proliferative phenomena. Epithelioid cells and collagen producing fibroblasts already conspicious in 3 week-old granuloma. According to the cytological composition the Mycobacterium marinum granuloma represents a high-turnover granuloma with immunogenic origin. It is comparable to mycobacterial diseases in the presence of well developed cell mediated immunity (Lupus vulgaris, tuberculoid leprosy). Degrading mycobacteria have been rarely detected in phagocytes and are compared with viable bacilli in macrophages of experimentally infected mice. Curved and annular parallel membranes (“worm-like structures”) in the cytoplasm of transformed macrophages and in fibroblasts presumably originate from the membranes of endoplasmic reticulum. Cord-like structures with transverse bands (periodicity 170–180 Å) in the lumen of RER of some fibroblasts are interpreted as intracellularly aggregated collagen precursors.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 167
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 263 (1978), S. 207-214 
    ISSN: 1432-069X
    Keywords: Wound healing ; Collagen metabolism ; Collagen degradation ; Fibroblasts ; Ultrastructure ; Wundheilung ; Kollagenstoffwechsel ; Kollagenabbau ; Fibroblasten ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Kollagenstoffwechsel in granulierenden Hautwunden der Ratte wurde mittels biochemischer, tracerkinetischer und elektronenmikroskopischer Methoden untersucht. Die Ablagerung von Kollagen in Hautwunden der Ratte war nicht nur das Ergebnis eines Anstiegs der Kollagensynthese, sondern wurde ebenso durch eine Abnahme des Kollagenabbaus bedingt. Unsere Ergebnisse zeigten signifikante Unterschiede im Kollagenumsatz zu verschiedenen Zeiten der Wundheilung. Der herabgesetzte Kollagenkatabolismus in den frühen Stadien der Wundheilung steuerte in entscheidender Weise zur Kollagenakkumulation im Wundgebiet bei. Während späterer Stadien, zum Zeitpunkt der Wundkontraktion und der Remodellierung der Narbe, stieg die Umsatzrate des Kollagens an. Die dargestellten Ergebnisse werden im Zusammenhang mit den allgemeinen Kriterien der Narbenbildung diskutiert.
    Notes: Summary Collagen metabolism in granulating wounds of rat skin was studied with biochemical, isotopic and electron microscopical methods. Deposition of collagen in rat skin wounds was not only the result of an increase in collagen synthesis but it was also caused by a decrease in collagen degradation. Our investigations showed significant differences in the collagen turnover at different times of wound healing. Decreased collagen catabolism at the early stages of wound healing contributed decisively to collagen accumulation in the wound area. At later stages, during wound contraction and remodelling of the scar, the rate of collagen degradation rose. The above-mentioned results are discussed in the context of general criteria of scar formation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 168
    ISSN: 1432-0533
    Keywords: Cultured ; Craniopharyngioma ; Typical ; Atypical ; Ultrastructure ; Electron microscopy ; Biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Craniopharyngiomas are tumors of the suprasellar area, which are often cystic, encapsulated and slow-growing. Certain of these tumors can behave in an aggressive manner and either invade surrounding structures or recur. In order to determine characteristics which may aid in distinguishing typical from atypical lesions, a study of biopsy and tissue culture specimens from 25 human craniopharyngiomas was undertaken. Tissue culture observations reveal two distinct cell populations. Typical lesions grew in culture in an orderly epithelial pattern and had desmosome-tonofibril aggregates and smooth surface topography demonstrable by electron microscopy. In the atypical tumors the cell growth was irregular, with mitotic activity, cholesterol crystals and features characteristic of neoplastic transformation, such as surface microvilli, an increase of cytoplasmic basophilia, size and number of nucleoli and retraction of cytoplasm. Correlation with the clinical status of the patients suggests that tumors of the four patients which exhibited atypical features in culture behaved more aggressively.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 169
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 42 (1978), S. 1-5 
    ISSN: 1432-0533
    Keywords: Dysplastic gangliocytoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of dysplastic gangliocytoma of the cerebellum, a rare disorder with unknown etiology and pathogenesis, was studied ultrastructurally. The intranuclear inclusions identified were not seen to be of viral origin. The ultrastructural characteristics of the abnormal cells support the prevailing theory that these cells represent hypertrophied granular neurons.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 170
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 44 (1978), S. 235-239 
    ISSN: 1432-0533
    Keywords: Choroid plexus papilloma ; Ultrastructure ; Cytoplasmic ; Inclusions ; Silver bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of choroid plexus papilloma were studied by light and electron microscopy. All had the typical papillary pattern, and, in addition, two exhibited solid areas of tumor growth which predominated in one case. PAS positive (diastase resistant) and argyrophilic cytoplasmic inclusions were present in all three tumors but were particularly abundant in the predominantly solid one. Ultrastructurally, the inclusions appeared as irregularly shaped structures containing lipid droplets, filamentous material and microtubules, and resembled the “silver bodies” of Biondi found in normal choroid plexus. Along with other ultrastructural features of normal choroid plexus, these cytoplasmic inclusions may be helpful in the differential diagnosis of papillary tumors involving the ventricular system.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 171
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 41 (1978), S. 119-124 
    ISSN: 1432-0533
    Keywords: Neuroblastoma ; Small-cell neoplasm ; Cerebral ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A small-cell neoplasm in the left temporal lobe of a 10 and a half year old boy was studied by light and electron microscopy. Routine sections of the mass showed a differentiating neuroblastoma with Homer Wright rosettes, several foci of immature neoplastic neurons (ganglion cells), many mitoses, arcas of necrosis and tumor vessels showing endothelial proliferation. Ultrastructurally, most cells resembled early fetal neuroblasts and also were similar to those in murine and peripheral human neuroblastomas.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 172
    ISSN: 1432-0533
    Keywords: Nemaline myopathy ; Neuromuscular junction ; Myotendinous junction-like structure ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Histological, histochemical and ultrastructural studies were performed on muscle biopsies from three siblings with congenital nemaline myopathy. Histological studies revealed type I fibre atrophy and type II fibre paucity. Ultrastructural studies of intramuscular nerves showed that the axonal diameters were very narrow compared with the width of myelin lamellae. Granular or membranous osmiophilic material occurred in the adaxonal Schwann cell cytoplasm and had a periodicity of 33–38Å. The neuromuscular junctions showed degenerative features such as glycogen granules or myelin figures in 27.1% of total terminal axons. The secondary synaptic clefts were markedly decreased in number and short in length. Myotendinous junction-like structures were found in 5.5% of the muscle fibres near the neuromuscular junctions, and often near sites of fibre-splitting. Rods in nemaline myopathy might be caused as a result of longitudinal splitting and disruption of fibres due to deficient regeneration of the muscle fibres associated with neurotrophic abnormalities.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 173
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 41 (1978), S. 169-171 
    ISSN: 1432-0533
    Keywords: Pituitary gland ; Oncocytic adenoma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two cases of oncocytic adenoma occurring in the pituitary are reported. Both were men aged 40 and 50 years respectively and there was no evidence of endocrine abnormality. In both the tumours many cells showed abundant acidophilic finely granular cytoplasm which had not stained positively with PAS-orange G stain. Electron microscopically the cells contained numerous mitochondria associated with marked reduction of other cytoplasmic organelles including the secretory granules.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 174
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 42 (1978), S. 223-229 
    ISSN: 1432-0533
    Keywords: Irradiation edema ; Gravimetry ; Ultrastructure ; Vesicular transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Focal brain edema limited to one cerebral hemisphere was produced by ultraviolet irradiation of the exposed cortex. Tissue water content was determined by the gravimetric method which allows microsampling. Therefore, the spread of edema around the small necrotic area could be mapped more precisely than by determination of dry weight which calls for larger samples. As early as 30 min following irradiation, hyperemia and swelling of the brain are observed under the operating microscope. This correlates with venous stasis, hyperemia, and broadened perivascular spaces around venules and large capillaries accompanied by a marked rise in the specific weight of the tissue. After 4 h an edema front can be observed spreading from the perinecrotic zone in which there is a marked rise in endothelial cell vesicular activity. Edema reaches maximum levels in the deep white matter at 48 h post irradiation with normalisation of the tissue water content after 96 h. The velocity at which the edema front spreads from the cortex to the periventricular area lies in the range of 0.25 mm/h. Edema reabsorption coincides with signs of retrograde micropinocytosis in endothelial cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 175
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 43 (1978), S. 153-159 
    ISSN: 1432-0533
    Keywords: Myelin ; Oligodendroglia ; Human pathology ; Ultrastructure ; Carbon monoxyde ; Anoxia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 24-year-old woman was found comatose after 2 days of cephalalgia and vomiting. An immediate diagnosis of carbon monoxyde poisoning was disclaimed when blood carbon monoxyde was found to be 1.75 ml/100. A diagnosis of acute intracranial hypertension led to trephination with ventricular punction and brain biopsy on the third day. The patient died on the eleventh day. Ultrastructural study of biopsy tissue showed nearly normal cortex, and injured white matter, with disrupted or destroyed myelin and pycnotic oligodendroglia in contrast with nearly normal axons, astrocytes, and capillaries. Autopsy showed a typical semioval center myelinopathy. After discussion of the histotoxic, vascular, and edema theories for myelinopathy pathogenesis, primary oligodendrogial lesion is considered, and correlated with the diphasic evolution often observed in the course of carbon monoxyde myelinopathy.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 176
    ISSN: 1432-041X
    Keywords: Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notes: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 177
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 220 (1978), S. 193-199 
    ISSN: 1434-4726
    Keywords: Cochlear spiral ganglion ; Ultrastructure ; Morphometry ; Influence of broad band noise ; Cochleare Spiralganglien ; Ultrastruktur ; Morphometrie ; Beschallung mit Breitbandrauschen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach 40minütiger Beschallung des Ohres mit Breitbandrauschen von 105 dB SPL waren bei den Ratten elektronenoptisch noch keine sicheren Veränderungen an den Spiralganglienzellen festzustellen. Erst ultrastrukturell-morphometrisch ließen sich statistisch signifikante Veränderungen des Chondrioms und der Organellen des Leistungsstoffwechsels bei den granulären Spiralganglienzellen nachweisen. Der Volumenanteil der Mitochondrien im Einheitsvolumen Zytoplasma nahm zu. Auch das Volumen und die Oberfläche des RER sowie das Volumen der freien Ribosomen und der Nucleolen vergrößerten sich im Einheitsvolumen Zytoplasma bzw. pro Zelle. Die physiologische Bedeutung dieser Veränderungen wurde diskutiert. Die Resultate zeigen u. a., daß Veränderungen der Cytoarchitektur in den granulären Spiralganglienzellen morphometrisch früher als elektronenoptisch registriert werden können.
    Notes: Summary The comparison of ultrastructural and ultrastructural-morphometric findings in spiral ganglion cells subsequent to broad band noise with 105 dB SPL over a period of 40 min demonstrates that there are morphometric changes of the cytoarchitecture of granular ganglion cells even without evident ultrastructural changes. Morphometric analyses shows a significant extention of the volume proportion of mitochondria per unit volume cytoplasm. The volume and the surface of the rough endoplasmic reticulum, the volume of the free ribosomes and the average single volume of the nucleoli increase per granular ganglion cell. The physiologic significance of these changes is discussed. The results show that changes of the cytoarchitecture of granular spiral ganglion cells are earlier detected by morphometry than by ultrastructural description.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 178
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 44 (1978), S. 249-250 
    ISSN: 1432-0533
    Keywords: Organelle complex ; Ribosomes ; Meningioma (malignant) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural study of a malignant meningioma revealed an organelle complex composed of: (1) A band-like densification of the cell cytoplasm adjacent to and in contact with the cell membrane. (2) An arciform filament immediately subjacent to it, with concavity directed away from the cell membrane. (3) A row of regularly spaced ribosomes located in the concavity, but at some distance from the arciform filament. (4) A pericellular condensation of interstitial ground substance. Occasionally, a second, thinner filament was seen “threading” the ribosomes together. Its morphology was consistent with that described for messenger RNA. It is suggested that the ribosomes are engaged in the synthesis of proteins for other portions of the organelle complex and that the ultimate role of the specialized unit would be that of an attachment device.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 179
    ISSN: 1432-0878
    Keywords: Tegmental reticular nucleus (Bechterew) ; Serotonin neurons ; Reticular formation ; Ultrastructure ; Synaptic organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organization of the tegmental reticular nucleus of von Bechterew (TRN) has been analyzed in Nissl and Golgi material, by fluorescence histochemistry, and by electron microscopy. In the albino rat, the TRN situated in the ventral paramedian midbrain and pontine reticular formation, contains two principal types of neurons. The first is a population of large multipolar neurons (40–80 μm diameter) with abundant Nissl substance and 4–7 smooth dendrites which may extend up to 500 μm in length. The second is medium-sized fusiform neurons (14–40 μm diameter) with less Nissl substance and two primary dendrites that originate from each pole of the soma and have a more closely ramifying dendritic field. Fluorescence histochemistry demonstrates that serotonin neurons constitute one component of the medium-sized neuron group. A third neuronal type, infrequently encountered at the outer margins of the nucleus, corresponds to the large, multipolar isodendritic neurons (soma diameter 40–80 μm) of the pontine reticular formation. Ultrastructural analysis of the TRN also demonstrates large and medium sized neurons which are present, together with numerous large dendritic trunks, between bundles of myelinated axons traversing the TRN in both rostrocaudal and transverse planes. This distinctive arrangement produces the appearance of “gray islands” between myelinated axon bundles. Within these areas, abundant synaptic terminals occupy a large proportion of the available terminal space on the surface of dendrites and perikarya, particularly of the large type of neuron. Two types of synaptic terminals are encountered; S-type synapses contain lucent spherical synaptic vesicles and F-type synapses contain flattened lucent vesicles. In addition there is a small number of synaptic terminals with scattered 100–120 nm diameter dense core vesicles in a population of smaller pleomorphic vesicles. These account for no more than 10% of the synaptic terminal population.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 180
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 194 (1978), S. 533-545 
    ISSN: 1432-0878
    Keywords: Corpus allatum ; Insects ; Ovariectomy ; Ultrastructure ; Cytophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corpora allata of 29 Leucophaea ovariectomized in the nymphal stage and maintained up to an adult age of 28 months was examined. In general, the subcellular morphology of these glands has much in common with that of normal female controls examined at the height of their activity. In addition, the most “typical”of the gonadectomy cases show certain distinctive features that are either absent or much less prominent in unoperated controls. Of primary interest is the striking abundance of smooth surfaced endoplasmic reticulum observed in many but not all of the castrates. Since this organelle is implicated in the biosynthesis of juvenile hormone, the factor normally responsible for yolk deposition, its increase, together with certain additional ultrastructural features, is indicative of an exceptionally high rate of hormone production. An explanation for the putative hyperactivity displayed to various degrees by the experimental animals may well be the constancy of the demand on their corpora allata, since removal of the ovaries abolishes the afferent signals in response to which, in the intact female, the brain turns off these glands during the long periods of gestation. That the synthetic effort may eventually level off, even in the absence of regular inhibitory stimuli, is suggested by the corpora allata of those castrates, the ultrastructure of which reflects moderate activity or possibly further regression
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 181
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 195 (1978), S. 59-79 
    ISSN: 1432-0878
    Keywords: Compound eyes ; Arthropod vision ; Deep-sea crustaceans ; Ultrastructure ; Thysanopoda tricuspidata (Euphausiacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The compound eyes of the mesopelagic euphausiid Thysanopoda tricuspidata were investigated by light-, scanning-, and transmission electron microscopy. The eyes are spherical and have a diameter that corresponds to 1/6 of the carapace length. The hexagonal facets have strongly curved outer surfaces. Although there are four crystalline cone cells, only two participate in the formation of the cone, which is 90–120 μm long and appears to have a radial gradient of refractive index. The clear zone, separating dioptric structures and retinula, is only 90–120 μm wide. In it lie the very large oval nuclei of the seven retinula cells. Directly in front of the 70 μm long and 15 μm thick rhabdom a lens-like structure of 12 μm diameter is developed. This structure, known in only a very few arthropods, seems to be present in all species of Euphausiacea studied to date. It is believed that the rhabdom lens improves near-field vision and absolute light sensitivity. Rod-shaped pigment grains and mitochondria of the tubular type are found in the plasma of retinula cells. The position of the proximal screening pigment as well as the microvillar organization in the rhadbdom are indicative of light-adapted material. The orthogonal alignment of rhabdovilli suggests polarization sensitivity. Behind each rhabdom there is a cup-shaped homogeneous structure of unknown, but possibly optical function. Finally, the structure and the function of the euphysiid eye are reviewed and the functional implications of individual components are discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 182
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 195 (1978), S. 111-122 
    ISSN: 1432-0878
    Keywords: Epidermis ; Skin ; Ultrastructure ; Rana ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organisation of the ventral epidermis organisation was followed throughout ontogenesis in Rana ridibunda. Epidermis of tadpoles with 2–3 limbs was organised into two layers: a stratum germinativum consisting of elongated columnar cells, and an outer stratum corneum consisting of two types of cuboid cells. Two types of cells can be distinguished; they are a light (clear) cell and a dark (dense) cell. In the 4-legged tadpoles the stratum corneum cells start to flatten and a replacement layer appeared underneath. A well-defined stratum germinativum is found and within it, epidermal glands. Moulting took place for the first time in tadpoles just before metamorphosis, and a well-organised stratum granulosum was formed still containing the two main types of epidermal glands. The flask cells appear in the juveniles for the first time, greatly increasing in numbers in the adult epidermis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 183
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 195 (1978), S. 461-469 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Cold ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural changes in pinealocytes were investigated qualitatively and quantitatively in mice exposed to low temperatures at 0° C or 5° C for 30 or 60 min. A quantitative estimation of the granulated vesicles of about 100 nm diameter in pinealocytes demonstrated that the number of these vesicles per pinealocyte in mice exposed to cold at 0° C or 5° C increased remarkably as compared with that of the controls. This finding indicates that cold stimuli may activate the formation of the granulated vesicles in pinealocytes. In mice exposed to cold at 0° C for 60 min, granulated vesicles were often found in groups close to the plasma membrane of the pinealocyte cell bodies or processes, indicating the release of the vesicle content into the extracellular spaces. Additionally, the pinealocytes of the mice exposed to cold at 0° C for 60 min were characterized by the frequent occurrence of lysosome-like bodies and filaments. The development of these structures in response to severe cold may represent a depressed functional state of pinealocytes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 184
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 189 (1978), S. 347-353 
    ISSN: 1432-0878
    Keywords: Vitelline membrane ; Chorion ; Ultrastructure ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The follicle cells of Foucartia squamulata are involved in the formation of both vitelline membrane and chorion. Precursors for these egg coverings are synthesized by the rough endoplasmic reticulum and condensed within dictyosomes. The vitelline membrane and the chorion appear on the oocyte surface simultaneously, which is an unusual phenomenon for insects. The follicular epithelium has not been found to contribute to vitellogenesis in the species under study.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 185
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 189 (1978), S. 365-374 
    ISSN: 1432-0878
    Keywords: Previtellogenesis ; Oocyte ; Ultrastructure ; Acerentomon gallicum ; Protura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary At the onset of previtellogenesis, the oocytes of Acerentomon gallicum begin to grow and increase their content of organelles. The nuage material in the oocytes at first increases in amount, then declines gradually to disappear completely from oocytes that have attained 50 μm in diameter. During the growth period, new dictyosomes, mitochondria and ribosomes appear. Numerous vesicles become detached from the cell membrane and subsequently fuse into cisternae, thus forming extensive complexes of the rough endoplasmic reticulum. In oocytes with diameters between 50 and 100 μm the Golgi complexes show a considerable increase in activity, and many lamellar bodies arise from mitochondria that have undergone specific transformation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 186
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 189 (1978), S. 435-440 
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Sinus gland ; Synapses ; Palaemon ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two types of neurosecretory fibers, designated as Type 5 and Type 6 axons, in the sinus gland of the freshwater prawn, Palaemon, establish contact with other neurosecretory axons by means of synaptic junctions. This finding strongly supports the view that release of some neurohormones from the eyestalk may be regulated by neurosecretory neurons through synaptic transmission.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 187
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 188 (1978), S. 205-215 
    ISSN: 1432-0878
    Keywords: Myocardium ; Mouse ; Ultrastructure ; Leptofibrils ; Desmosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The papillary muscle of the heart of adult white mice is investigated. Intrafibrillarly located leptomeric fibrils, frequently encountered in the Z-band region of the myofibrils. The leptomeric fibrils are always running in a transverse direction and often in close proximity to the transverse tubules (which are also located at this level). There seems to be a close connection between the dense striae of the leptofibrils and the Z-bands of ordinary myofibrils. The leptomeric fibrils are spindle-shaped and have a length varying between 0.6 and 1.2 μm. The banding periodicity of the fibrils is approximately 0.16 μm. Occasionally desmosomes are observed in the T-tubule system.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 188
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 188 (1978), S. 189-204 
    ISSN: 1432-0878
    Keywords: Neural lobe of hypophysis ; Hibernating mammals ; Ultrastructure ; Neurosecretory granules ; Whorls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'ultrastructure de la posthypophyse du Lérot a été examinée à différents stades du cycle annuel de ce rongeur hibernant. Il n'a pas été observé de différences évidentes entre les stades étudiés, et sont donc présentées ici les caractéristiques générales retrouvées chez tous les animaux. Les axones neurosécréteurs et leurs terminaisons peuvent être divisés en deux catégories suivant l'aspect des grains de neurosécrétat et des microvésicules présents. Le premier type contient des grains arrondis, à contenu d'apparence homogène, avec des microvésicules rondes. Dans les autres axones, les grains sont de forme variable, souvent allongés, et leur contenu présente deux sortes d'organisations cristallines; les microvésicules y sont en majorité aplaties. Considérant comme improbable que cette dualité résulte seulement d'un artefact, trois hypothèses sont envisagées. La dualité d'aspect des grains peut être liée à leur contenu en hormone (ocytocine ou vasopressine); ou bien l'aspect des grains peut correspondre à leur degré de maturation. Il est possible aussi que ces explications soient toutes deux valables. Par ailleurs, les pituicytes du Lérot contiennent fréquemment un réticulum endoplasmique organisé en lamelles concentriques (whorls). La signification de ces formations reste pour l'instant obscure.
    Notes: Summary Ultrastructural examination of the posterior pituitary of the garden dormouse (Eliomys quercinus L.) was carried out at different times in the annual cycle of this hibernating rodent. Obvious differences between experimental groups have not been observed, and the results presented here must be considered as general features of the garden dormouse posterior pituitary. Neurosecretory axons and endings can be divided into two types, according to different aspects of neurosecretory granules (NSG) and microvesicles (MV). One type contains spherical NSG with homogeneous cores and round MV. In the other type, NSG have various, often elongated, shapes. Their content shows two types of crystalline structures and most of the MV have flattened aspects. As it is very unlikely that this duality in NSG is a result of an artefact of fixation, three hypotheses are presented as explanation. The duality of NSG might be related either to their hormonal content (oxytocin or vasopressin) or to their degree of maturation. Moreover, both explanations may be valid. In the species studied, pituicytes often contain concentric lamellar structures of the endoplasmic reticulum (whorls), the significance of which remains obscure.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 189
    ISSN: 1432-0878
    Keywords: Adrenal ; Steroidogenesis ; Inihibitor ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In concert with studies of the effects of various pharmacologic inhibitors of corticosteroidogenesis on adrenocortical morphology, U-8113, an analog of amphenone B, was administered daily to Sprague-Dawley rats for 7, 14, 21 or 30 days. The primary morphological responses involved increases in adrenal weight, width of zona fasciculata, width of zona reticularis, intracellular lipids, mitochondrial size, mitochondrial vacuolation and crystalline-like inclusions, small coated vesicles, lysosomes, autophagic vacuoles and cholesterol ester clefts. In particular, the increases in lysosomes, coated vesicles and autophagic vacuoles containing morphologically altered mitochondria were considered reflective of mechanisms designed to maintain cellular integrity amidst functional impairment. Lipid analysis revealed marked increases in cholesterol esters and phospholipids, supportive of morphological observations. When permitted a 14 day recovery period following either 14 or 30 days of inhibitor therapy, most fine structural alterations and lipid derangements were diminished, and the cells approximated normal parameters.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 190
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies were made of the regeneration of minced smooth muscle of the vas deferens of the guinea-pig 3 days to 15 weeks after operation. At 3–5 days the mince contained degenerating smooth muscle cells and dedifferentiating cells showing characteristics of embryonic smooth muscle cells: numerous free ribosomes, well developed rough endoplasmic reticulum and Golgi apparatus with few peripherally placed myofilaments associated with dense bodies. During the first two weeks of regeneration, scattered cells surrounded by debris and collagen were separated by a large extra-cellular space. After three weeks, extracellular space was reduced to near normal values. Regenerating cells had a shorter length than normal cells, but during later stages of regeneration they showed an increase in diameter. Muscle effector bundles began to form after 2 to 3 weeks. Initially there were large gaps between the muscle cells, but at later stages of bundle formation, the extracellular space between the muscle cells was much reduced. From 3 weeks, arterioles appeared between the smooth muscle bundles in the regenerating areas. Regeneration of individual smooth muscle cells was complete by 15 weeks after the operation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 191
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Golden mole ; Secretory process ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les pinéalocytes de la glande pinéale de la Taupe dorée Amblysomus hottentotus (Mammifère aveugle et vivant toujours dans une obscurité complète) examinés au microscope électronique ont été comparés à ceux d'autres Mammifères. Une seule population de pinealocytes a été observée. Mitochondries, ribosomes, réticulum endoplasmic granulaire, inclusions lipidiques et rares structures lysosomiales sont présents dans le périkaryon. De nombreux grains de glycogène formant le plus souvent de typiques “accumulations” ont été fréquemment observés associés à des vacuoles. Un grand nombre de vésicules granulaires est la caractéristique première des pinéalocytes. Un phénomène d'excrétion, caractérisé par une dissolution in situ du coeur dense, a été observé. L'importance physiologique de ces vésicules granulaires est discuté.
    Notes: Summary The ultrastructure of the pinealocytes of the golden mole (Amblysomus hottentotus), a blind subterranean mammal living in complete darkness, was examined and compared with that of pinealocytes of other mammals. On the basis of the presence of granular vesicles and glycogen granules, only one population of pinealocytes was found. Large mitochondria, ribosomes, lipid inclusions and scarce lysosomes were observed in the perikaryon. Numerous glycogen granules, often forming typical accumulations, were frequently found to be associated with typical vacuoles. An extraordinary large number of granular vesicles is characteristic of the golden mole pinealocyte. Phenomena of excretion of compound(s) stored in the granular vesicles were identified. Morphologically this is characterized by dissociation of its granular core in situ while its limiting membrane is preserved. The physiological significance of the secretory process characterized by the formation of these granular vesicles is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 192
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 191 (1978), S. 101-114 
    ISSN: 1432-0878
    Keywords: Sperm host glands ; Quail (Coturnix coturnix jap.) ; Ultrastructure ; Ultracytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and ultrahistochemical studies were performed on the uterovaginal sperm host glands of the quail (Coturnix coturnix japonica). The proximal parts of the glandular necks are lined by a pseudostratified epithelium, consisting of high columnar ciliated cells and small, irregular shaped, basal cells. The true glandular epithelium is composed only of columnar cells with microvilli on their luminal end. A characteristic luminal feature is a large lipid droplet in the perinuclear region. In the subplasmalemmal region numerous tubular profiles are seen which could represent a cellular resorption system. To evaluate the absorptive capacity of the Uterovaginal sperm host glands, tracer studies with HRP, ferritin, lanthanum and ruthenium red were undertaken. Since between 5 min and 3 h after injection no absorption could be found with the techniques mentioned, it is suggested that phagocytosis of spermatozoa by the glandular epithelium is not likely to occur.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 193
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 191 (1978), S. 233-247 
    ISSN: 1432-0878
    Keywords: Nervous system ; Pluteus ; Ultrastructure ; Echinoderms ; Strongylocentrotus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tissues that have the ultrastructural characteristics of nervous tissues are associated with ciliary and muscular elements of the pluteus larva of Strongylocentrotus purpuratus. The nerve cells are found along the margins of the ciliary bands, which are composed predominantly of spindle-shaped ciliated cells. The nerve cells contribute axonal processes to a tract of axons, which runs at the base of the ciliary band throughout its length. Axonal tracts, in the esophagus, lie beneath the circumesophageal muscles. Branched microvilli, which have been interpreted as sensory receptors, are located on the oral side of the main ciliary band and connect with the nerve cells in the ciliary band. The nervous structures described here, and other tissues of the pluteus that have been previously described as nervous, are compared on the basis of their association with receptor and effector organs, and their ultrastructural characteristics.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 194
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 191 (1978), S. 267-286 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Supraoptic nucleus ; Paraventricular nucleus ; Ultrastructure ; Brattleboro rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothalamo-posthypophysial complex of the homozygous Brattleboro rat is characterized by a hyperactivity of its neurons. The neurosecretory fibers, especially in the neurohypophysis, show numerous signs of autophagy and tubular proliferation of the axoplasmic reticulum. These structural alterations, as well as the nematosomes or nucleolus-like bodies encountered in the perikarya, may be related to the chronic hyperactivity of the neurons. They can be reduced by administration of exogenous vasopressin. The numerous liposomes in the pituicytes are paralleled in the neuronal perikarya by a great number of lysosomes. Small dense core vesicles observed in the neurosecretory endings and perikarya may indicate a secretory product distinct from oxytocin and vasopressin. In the homozygous Brattleboro rat, endings of the aminergic type are more numerous than in the normal rat. With respect to the role they may play in the secretory processes, their increase might be secondary to the vasopressin deficiency.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 195
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 191 (1978), S. 343-356 
    ISSN: 1432-0878
    Keywords: Lung ; Amphibia ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and morphometric investigations were performed on the lung of the European salamander, Salamandra salamandra L. Folds of first and second order are covered with a ciliated epithelium containing goblet cells. The respiratory surface of the lung is lined by a single type of cell which, in amphibians, combines features of type I and type II alveolar cells of the mammalian lung. In the salamander the respiratory and ciliated epithelial cells as well as goblet cells possess electron dense and lucent vesicles in their cytoplasm as well as lamellar bodies. A small amount of surfactant, composed most probably of phospholipids and mucopolysaccharides, was observed covering the entire inner surface of the lung. Morphometric methods were used to determine the dimensions of the perinuclear region of pneumocytes, the thickness of the air-blood barrier and lung wall, and also the diameter of capillaries. The thickness of the respiratory air-blood barrier was found to be considerably higher than that of the corresponding barrier in mammals.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 196
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 186 (1978), S. 327-335 
    ISSN: 1432-0878
    Keywords: Cuticle ; Epidermis ; Chironomus ; Respiration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larval integument of the midge, Chironomus riparius Mg., is unusually thin although it conforms with the normal insect pattern. The cuticle of the post-cephalic segments is about 3 μm thick and overlies an epidermis which has an irregular basal plasma membrane resulting in spaces occurring between it and the basement membrane. The ventral tubuli have a similar epidermis but the cuticle is somewhat thinner. The anal papillae have the thinnest cuticular covering with a uniquely folded epicuticle of variable thickness, and their epidermis has the characteristics of a transporting epithelium. No evidence of pore canals could be found in the cuticle of any part except the head capsule which has a remarkably smooth epicuticle and a distinct layer which may represent the exocuticle. There are no spaces between the basement membrane and basal plasma membrane of the epidermis in the head. Ultrastructural evidence would suggest that gaseous exchange can occur across most of the post-cephalic integument.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 197
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 186 (1978), S. 499-506 
    ISSN: 1432-0878
    Keywords: Fat body ; Aedes aegypti ; Vitellogenin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the fat body of Aedes aegypti was followed from emergence through a blood meal. Changes in the volume of protein granules and lipid droplets were also examined. The relationship of these events to the known endocrinology of vitellogenin synthesis in mosquitoes is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 198
    ISSN: 1432-0878
    Keywords: Area postrema ; 6-Hydroxydopamine ; Degenerative changes ; Ultrastructure ; Cynomolgus and squirrel monkeys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 6-Hydroxydopamine (6-OH-DA) has been shown to produce degenerative changes in noradrenergic nerve terminals and preterminals in the CNS following intracisternal, intraventricular or direct injection into the brain parenchyma. Systemic injection of 6-OH-DA is known to result in degenerative changes in noradrenergic terminals in the peripheral nervous system. However, only a few studies have been carried out on the effects of systemic injections of 6 OH-DA on noradrenergic terminals in the CNS. In the present study cynomolgus and squirrel monkeys were injected intravenously on two successive days with total doses of 350mg/kg and 150 mg/kg of 6-OH-DA, respectively, and sacrificed at 2 and 24 h following the second injection. Degenerative changes in the area postrema (AP) neurons in all injected animals were characterized by a generalized increase in electron density of cytoplasmic elements in axonal terminals and preterminals. Multilamellar bodies, clusters of clear and dense core vesicles, increased numbers of secondary lysosomes, and an increase in the number of glycogen granules were observed in these structures. In astrocytes the amount of glycogen increased markedly in injected animals, but no other glial alterations were observed. The number of mast cells in the AP was greater in injected than in noninjected animals, both in the perivascular spaces (PVS) and in parenchymal locations. Cell processes in the PVS were occasionally observed to contain electron dense bodies, and degenerative changes were seen in supraependymal processes in some injected animals.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 199
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 187 (1978), S. 135-146 
    ISSN: 1432-0878
    Keywords: Osteodentine ; Anarhichas lupus ; Ultrastructure ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le tissu dentinaire d'Anarhichas lupus s'est révélé être une ostéodentine vasculaire. Les études en MET, MEB et diffraction X montrent l'hétérogénéité de ce tissu. L'aspect désordonné des fibres de collagène, incomplètement minéralisées (leur striation est encore bien visible), explique la complexité de la répartition des cristaux puisqu' elles en déterminent l'ordonnance. La minéralisation imparfaite du tissu, dont témoignait déjà la striation visible du collagène, est confirmée par l'analyse des poudres en diffraction X (la cristallinité de l'ostéodentine vasculaire est nettement inférieure à celle de la couche de tissu dentaire périphérique) et par l'examen en MET de haute résolution, aucun réseau cristallin n'ayant pu être mis en évidence. L'ostéodentine, l'os basal et l'os profond ont en commun une phase minérale, avec une organisation plus ou moins bonne, différente du système des apatites.
    Notes: Summary TEM, SEM and X-ray diffraction analysis demonstrate the heterogeneity of the dentinal tissue of Anarhichas lupus, a vascular osteodentine. The disordered aspect of collagen fibres, incompletely mineralized (the periodical striation being still visible), explains the scattered distribution of crystallites since they are responsible for their arrangement. The low degree of mineralization revealed by the visible collagen striation is confirmed by X-ray diffraction analysis (the crystallinity of vascular osteodentine being much lower than that of the peripheral dental tissue) as well as by high resolution TEM, since no lattice planes could be observed. Osteodentine, supporting bone and proper bone have in common a mineral phase, more or less organized, different from the apatite system.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 200
    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Epithelium ; Renewal ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intestinal absorptive epithelium of starved and fed fish has been studied electron microscopically. After feeding, cells of the proximal segment of the intestine show morphological characteristics of lipid absorption. Absorptive cells in the middle segment contain many pinocytotic vesicles in both fasted and fed specimens. Absorption of protein macromolecules is supposed to be one of the main functions of this part of the gut. In the most caudal part of the intestine, absorptive cells carry relatively few and short microvilli. The proximal and distal segments show structural indications of a function in osmoregulation. The renewal of the epithelium has been studied with light microscopic autoradiography, using tritiated thymidine. The intestinal mucosal fold epithelium represents a cell renewal system. The cells proliferate at the base of the fold and migrate towards the apex in 10–15 days at 20° C. The functional absorptive cells proved to be generally present in the intestinal epithelium, including the proliferative area. Undifferentiated cells have not been identified. The results will be compared with data on absorption of lipid and protein macromolecules in teleostean and mammalian intestines and with descriptions of the cell renewal system in the mammalian intestine.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...