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  • 1970-1974  (5,150)
  • Inorganic Chemistry  (3,865)
  • Ultrastructure  (453)
  • Electron microscopy  (425)
  • Computational Chemistry and Molecular Modeling  (408)
  • Nuclear reactions
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Keywords
  • 101
    Electronic Resource
    Electronic Resource
    Ultrastructural investigations of the palisade-shaped nerve fiber terminals of the normal hairs of rat's snout (1974)
    Springer
    Cell & tissue research 147 (1974), S. 259-269 
    Details
    ISSN: 1432-0878
    Keywords: Nerve endings ; Hair ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Palisade-shaped nerve endings of the small normal hairs of the rat snout were examined with the electron microscope (fixation by perfusion). The terminals are located inside the ‘glassy membrane’ in the area of the neck of the hair root. The 10–20 radially arranged terminal axons are in direct contact with the basement membrane of the epithelium of the external root sheath. The axons are surrounded on all sides by leaf-shaped processes of the Schwann cells. The surfaces of these cell processes are marked by numerous vesicle-like invaginations (approx. 1000 Å dia.). Transverse sections from several areas of the palisadeshaped nerve endings are compared with longitudinal sections. In the upper area ‘empty’ vesicles (approx. 500–600 Å in diameter) occur, along with electron-dense vesicles (approx. 800–1100 Å in diameter); in the middle area, the axons are distended and contain accumulations of mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582800
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  • 102
    Electronic Resource
    Electronic Resource
    Fine structure of the excretory system of Amphioxus (Branchiostoma floridae) and its response to osmotic stress (1974)
    Springer
    Cell & tissue research 148 (1974), S. 1-9 
    Details
    ISSN: 1432-0878
    Keywords: Branchiostoma ; Osmoregulation ; Cyrtocytes ; Podocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The excretory organs of Amphioxus occur as segmentally arranged structures throughout the pharyngeal region and may be divided into three components: the solenocytes, the renal tubule, and the renal glomerulus. The solenocytes possess foot processes that rest upon the coelomic surface of the ligamentum denticulatum. The tubular apparatus of the solenocytes consists of ten triangular rods surrounding a central flagellum. The distal end of the tubular apparatus enters branches of the renal tubule. The renal tubule eventually opens into the atrial cavity of Amphioxus. The renal glomerulus is a sinus within the connective tissue of the ligamentum dentieculatum where it connects elements of the branchial circulation with the dorsal aorta. The renal glomerulus, like other blood vessels of Amphioxus, lacks an endothelial lining. If Amphioxus is adapted to artificial sea water at different concentrations there is no change in kidney morphology suggesting that Amphioxus is either is osmotic with its environment or is osmoregulating with other organs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224314
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  • 103
    Electronic Resource
    Electronic Resource
    The ultrastructure of the accessory sex organs of the male rat (1974)
    Springer
    Cell & tissue research 148 (1974), S. 57-67 
    Details
    ISSN: 1432-0878
    Keywords: Prostate ; Rat ; Cyproterone ; Alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The dorsal lobe and the coagulating gland of the rat prostate were studied after administration of the anti-androgenic compound Cyp A for varying periods (7–20 days). There was a general involution of the organs with macroscopic atrophy and reduced amount of secretory material. Ultrastructurally the cells were pale, contained less organelles as compared with the controls, loss of cytoplasm and reduction both of cell height and width. The major changes also included reduction of the Golgi area, the rough endoplasmic reticulum and the number of free ribosomes. Within the dorsal lobe prominent nuclear changes were found, comprising different types of intranuclear inclusions of membranous configurations. The alterations observed in the present study are similar to the changes which were found in castrated animals and are consistent with atrophy. The results are discussed in relation to the available biochemical and autoradiographic data on the different lobes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224318
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  • 104
    Electronic Resource
    Electronic Resource
    Ultrastructure of mucosal mast cells in normal and compound 48/80-treated rats (1974)
    Springer
    Cell & tissue research 150 (1974), S. 95-105 
    Details
    ISSN: 1432-0878
    Keywords: Mucosal mast cells ; Rat ; Compound 48/80 ; Degranulation, Release ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mast cells in the tongue and lamina propria of the duodenal mucosa, representing two cell types with different morphological, histochemical and functional properties have been studied under the electron microscope. Both cell types were found to contain similar moderately electron dense and homogeneous granules surrounded by a tight membrane constituting the basic ultrastructural characteristics of mast cells. The mucosal mast cells, however, contained fewer granules per cell and the individual granules often exhibited considerable variation in size. In addition the mucosal mast cells, unlike those of the tongue, peritoneum and skin, had a smooth plasma membrane lacking microvilli and possessed irregularly shaped or lobulated nuclei. In the tongue mast cells, administration of Compound 48/80 caused the formation of vacuoles around the granules, expulsion of granules from the cells and disintegration of the granular matrix, but no changes that could be attributed to 48/80 could be found in the mucosal mast cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220383
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  • 105
    Electronic Resource
    Electronic Resource
    Investigations on adrenocortical mitochondria turnover (1974)
    Springer
    Cell & tissue research 150 (1974), S. 79-94 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mitochondria ; ACTH ; Stereology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a chronic administration of ACTH (up to 36 consecutive days) on the mitochondria of the zona fasciculata of the rat adrenal cortex were investigated by stereologic techniques. It was found that, while the volume of the mitochondrial compartment significantly increases in relation to the duration of treatment, the size and number of mitochondria display a different pattern. Up to the 9th day of hormone treatment mitochondria significantly increase in volume, whereas their number per cell is only slightly increased. After 12 days of ACTH-treatment there is a tremendous increase in the number of organelles per cell, resulting in a significant decrease in their average volume. After 24 and 36 consecutive days of treatment the number of mitochondria per cell as well as their average volume both show a slight but significantly constant increase. The hypothesis that ACTH controls the processes of growth and division of adrenal mitochondria is discussed in the light of evidence indicating that mitochondria contain a complete genetic apparatus largely independent of nuclear control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220382
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  • 106
    Electronic Resource
    Electronic Resource
    Nerve endings in the arteria centralis retinae (1974)
    Springer
    Cell & tissue research 150 (1974), S. 143-145 
    Details
    ISSN: 1432-0878
    Keywords: Arteria centralis retinae ; Cat ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Terminal axons emerging from the inner plexiform layer of the cat retina reach the wall of the arteria centralis retinae, as revealed by electron microscopy. Numerous unusually large dense core vesicles (about 1000 Å in diameter), of different electron densities, occur in the varicosities of these axons. These observations may be compatible with the idea of an innervation of the central artery of the retina which is non-autonomic, possibly intrinsic in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220387
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  • 107
    Electronic Resource
    Electronic Resource
    Ultrastructure of rat pituitary gonadotrophs following incubations of the gland with synthetic LH-RH (1974)
    Springer
    Cell & tissue research 150 (1974), S. 179-192 
    Details
    ISSN: 1432-0878
    Keywords: Rat anterior pituitary ; FSH and LH-gonadotrophs ; Luteinizing releasing hormone ; “Signet cells” ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The action of luteinizing releasing hormone (LH-RH) on FSH and LH-gonadotrophs from the anterior pituitary glands of normal rats has been studied with electron microscopy. After 15 min. incubation with LH-RH, LH cells showed secretory granules undergoing exocytosis, but FSH did not appear to release secretory products. On the other hand, incubations with the releasing hormone for 3 and 6 hr stimulated exocytosis from both FSH and LH-gonadotrophs. Of more interest was the finding that FSH cells appeared as typical “signet cells” of castration when glands were incubated for 3 and 6 hr with the releasing hormone. The appearance of such “signet cells” was prevented if puromycin was added to the medium together with LH-RH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222169
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  • 108
    Electronic Resource
    Electronic Resource
    In vitro maturation of Arbacia punctulata oocytes and initiation of heavy body formation (1974)
    Springer
    Cell & tissue research 150 (1974), S. 271-279 
    Details
    ISSN: 1432-0878
    Keywords: Heavy bodies ; Oogenesis ; Maturation ; Sea urchin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural study of in vitro maturation of A. punctulata oocytes was undertaken to determine when heavy body formation was initiated. No heavy bodies were seen in germinal vesicle oocytes or in oocytes undergoing germinal vesicle breakdown or polar body formation. Heavy bodies were only observed in ova examined one to two hours after pronuclear formation. Several small heavy bodies were seen in sections of eggs fixed as early as three hours after the pronucleus had formed. The number of these structures in the egg cytoplasm increased with time. Therefore it is concluded that heavy body formation in sea urchin ova is a phenomenon following nuclear maturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222175
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  • 109
    Electronic Resource
    Electronic Resource
    The biochemical nature of the cell periphery of the salt gland secretory cells of fresh and salt water adapted mallard ducks (1974)
    Springer
    Cell & tissue research 150 (1974), S. 193-211 
    Details
    ISSN: 1432-0878
    Keywords: Avian salt gland ; Electrolyte transport ; Ultrastructure ; Ruthenium red ; Dialyzed iron ; Sialic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Both ruthenium red and dialyzed iron techniques indicated that anionic protein-carbohydrates were associated with the plasmalemma of secretory cells in mallard salt glands. Digestion of the tissue with neuraminidase prior to dialyzed iron staining provided evidence that much of the anionic nature of this surface was due to sialic acid. These results were confirmed by biochemical assays showing that the salt-gland tissue contained a relatively high sialic-acid content and that the amount of sialic acid increased with salt-water adaptation. Possible roles of these anionic sites are discussed in relation to currently accepted hypotheses of electrolyte transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222170
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  • 110
    Electronic Resource
    Electronic Resource
    The role of the nervous system in regeneration, growth and cell differentiation in Hydra (1974)
    Springer
    Cell & tissue research 150 (1974), S. 231-247 
    Details
    ISSN: 1432-0878
    Keywords: Regeneration ; Nerve cells ; Neurosecretion ; Hydra ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Major ultrastructural changes in neurons were studied during sequential periods of hypostomal regeneration in Hydra. Some neurons remain unaffected except that at certain periods following amputation, they become more active in neurosecretory production. Other neurons in various stages of differentiation were also observed. Most emphasis was placed on degenerating neurons showing a loss of organelles and destruction of the perikarya. Certain large, membrane-bounded structures (up to 1.7 μ in diameter) suggested tentatively to be of a lysosomal-like nature, may be partly responsible for the degenerative process. The neurites of these cells first assume a beaded appearance and/or contain bulbous endings. The eventual isolated fragments of neurites contain typical membrane-bounded neurosecretory droplets (850/1700 Å in diameter) which disintegrate forming particulate materials (350 Å in diameter). Following complete disruption of the neurites, some of the granules accumulate in the extracellular spaces before they are disintegrated. From the data presented in this and the preceding paper, it is suggested that these particles, derived from neurosecretory droplets, may be responsible for the stimulation of: 1) interstitial cell differentiation into neurons, 2) the increased activity in neurosecretory production in normal cells, 3) the conspicuous increase in neurite length and consequently the exaggerated degree of anastomosis, and 4) the possible capacity of neurons to regenerate neurites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222172
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  • 111
    Electronic Resource
    Electronic Resource
    Haematopoiesis in the freshwater snail Lymnaea stagnalis studied by electron microscopy and autoradiography (1974)
    Springer
    Cell & tissue research 150 (1974), S. 443-454 
    Details
    ISSN: 1432-0878
    Keywords: Haematopoiesis ; Lymnaea stagnalis ; Amoebocytes ; Autoradiography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to investigate haematopoiesis in the freshwater pulmonate Lymnaea stagnalis, the blood cells and the connective tissue of this snail were studied by light and electron microscopy as well as by autoradiography. In the circulating blood only one type of cell, the amoebocyte, is present. Amoebocytes also occur in the connective tissue (tissue amoebocytes) as single cells, in small groups or in large accumulations. Study of the morphology and ultrastructure of blood and tissue amoebocytes shows that no differences exist between these cells, indicating that L. stagnalis does not possess a well-defined haematopoietic organ. This assumption is supported by the following observations: 1. both blood and tissue amoebocytes can act as phagocytes, 2. blood and tissue amoebocytes both have the capacity to divide (i.e. incorporate tritiated thymidine) and 3. the percentage of dividing cells in the blood and in the connective tissue is the same. These quantitative data indicate furthermore that there is no difference in the relative importance of the blood and the connective tissue in the process of haematopoiesis. Comparison of tritiated thymidine labelled cells with unlabelled amoebocytes showed that these cells do not differ with respect to their morphology and ultrastructure. Moreover, amoebocytes involved in phagocytosis and encapsulation of foreign materials or in wound healing still have the capacity to divide. The percentages of tritiated thymidine labelled amoebocytes in different snails varied considerably. It is suggested that this variation reflects differences in the physiological state of the individual snails.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225968
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  • 112
    Electronic Resource
    Electronic Resource
    Ultrastructure of the lamina propria in the ovine seminiferous tubule (1974)
    Springer
    Cell & tissue research 150 (1974), S. 481-492 
    Details
    ISSN: 1432-0878
    Keywords: Seminiferous tubule, ovine ; Lamina propria ; Development ; Endocrine factors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the lamina propria in the ovine seminiferous tubule was studied from 54 days (postcoitum) fetuses up to sexual maturity. In young animals (aged about two months) the effect of hypophysectomy and/or hormones was also analyzed. Initially, large areas of the lamina propria already show signs of morphological differentiation. The non cellular component is a single or sometimes double lamella. Outwardly, the cellular component is represented by rounded connective tissue cells or by elongated cells, exhibiting 80 Å filaments in the cytoplasm and arranged in 3 to 4 layers. By the first week after birth, the non cellular component is formed by 8 to 10 lamellae and the cellular component shows typical contractile cells, the fibroblasts being now located only in the periphery. Basically, the same aspect is found in the adult ram, thus differing from the more extensively studied prototypes of lamina propria architecture of rodents or primates. In as much as the sheep lamina propria differentiates precociously, probably induced by fetal testicular hormones, it is relatively insensitive to hypophysectomy or hormonal substitution. Hypophysectomy and cyproterone acetate administration cause intracytoplasmic lipid deposition in the contractile cells, the other components being not changed. Some questions are raised concerning the role of this peculiar lamina propria in the function of the blood-testis barrier.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225971
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  • 113
    Electronic Resource
    Electronic Resource
    Ultrastructural observation of possible nerve endings in rat sebaceous gland (1974)
    Springer
    Cell & tissue research 150 (1974), S. 545-552 
    Details
    ISSN: 1432-0878
    Keywords: Skin, rat ; Cytology ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural elements within the parenchyma of the sebaceous gland have not been reported previously. Nerve endings have been observed only in the connective tissue surrounding the gland or in close association with the undifferentiated basal cells. In this study, electron microscopy revealed the possible presence of nerve endings (or terminal portions of neural elements) in the suprabasal level of functional sebaceous glands of pinnae of white rats. Morphologically, there are two distinct types of nerve endings. Type 1 is bordered by a membrane of relatively irregular contour and contains a single mitochondrion, various-sized vesicles, numerous microtubules, fine neurofilament-like fibrils, and occasional ribosome-like granules. Type II is also bordered by a membrane, but its contour was relatively smooth and rounded. Moreover, Type II contains many mitochondria, varying in size, density, and the arrangement of cristae. While ribosome-like granules are scattered throughout the structure in relative abundance, there are scarcely any fine neurofilament-like fibrils or microtubules. Whether these two structures are sensory or autonomic fibers could not be determined by electron microscopic examination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225977
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  • 114
    Electronic Resource
    Electronic Resource
    The ultrastructure of the human fetal pineal gland (1974)
    Springer
    Cell & tissue research 152 (1974), S. 13-30 
    Details
    ISSN: 1432-0878
    Keywords: Human fetal pineal gland ; Development ; Secretion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the pineal gland of 18 human fetuses (crown-rump lengths 30–178 mm) was investigated. The pineal gland exhibits a pyramidal shape and consists of an anterior and posterior lobe. Only one parenchymal cell type, the pinealocyte, was observed. Few neuroblasts were seen between the pinealocytes and in the extended perivascular space. The pinealocytes possess all the organelles necessary for hormone synthesis. No specific secretory granule could be observed. The organ is abundantly vascularized and richly innervated. The morphology of the capillaries indicates the existence of a blood-brain barrier. The ultrastructure of the human fetal pineal gland suggests that the gland has a secretory function in early intrauterine life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224208
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  • 115
    Electronic Resource
    Electronic Resource
    An ultrastructural analysis of myelin in the central nervous system of an amphibian (1974)
    Springer
    Cell & tissue research 152 (1974), S. 51-67 
    Details
    ISSN: 1432-0878
    Keywords: Myelin ; Ventral habenular nuclei ; Interpeduncular nucleus ; Rana esculenta ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural analysis of myelin in the ventral habenular and in the interpeduncular nuclei of the adult frog Rana esculenta has been carried out. In the ventral habenular nuclei, in addition to normally myelinated fibres, some myelin irregularities have been observed. They consist of myelin enwrapping the perikarya of some neurons and of isolated flaps of collapsed myelin. In the interpeduncular nucleus numerous myelinated fibres occur but few redundant myelin irregularities have been noticed. The morphological data suggest that myelination of fibres in these sites is due to the spiral wrapping mechanism from a glial cell process while the myelin irregularities described in the ventral habenular nuclei are probably due to membrane synthesis within the cytoplasm of the myelinated neurons and of the oligodendrocytes which are sometimes observed in contact with the ensheathed neurons. In the interpeduncular nucleus myelinated fibres indenting astrocytes and oligodendrocytes have been observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224210
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  • 116
    Electronic Resource
    Electronic Resource
    Morphometric analysis of the midgut of female Aedes aegypti (L.) (insecta, diptera) under various physiological conditions (1974)
    Springer
    Cell & tissue research 152 (1974), S. 31-49 
    Details
    ISSN: 1432-0878
    Keywords: Aedes aegypti ; Midgut epithelium ; Cytology ; Morphometry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Ultrastruktur des Mitteldarmes von Aedes aegypti Weibchen wurde morphometrisch untersucht. Besonderes Interesse lag dabei auf quantitativen Unterschieden im Bau der Epithelzellen eines vorderen (A) und eines hinteren (P) Abschnittes des Mitteldarmes, um jedem dieser beiden Abschnitte bestimmte Funktionen zuordnen zu können. 5 physiologisch verschiedene Stadien wurden verglichen: 1 = unreife Weibchen; 2 = zum 1. Blutmahl (B.M.) bereit; 3 = Verdauung des B.M.; 4 = zum 2. B.M. bereit; 5 = alternde Weibchen. Wenn der Mitteldarm noch nicht funktionsbereit ist (Stadium 1) gleichen sich die Epithelzellen von A und P quantitativ ultrastrukturell. In den folgenden Stadien hingegen werden deutliche Unterschiede sichtbar. Das Zellvolumen und die Kern-Cytoplasma-Relation werden in P generell größer als in A. Parallel dazu nehmen der Mitochondriengehalt und die Oberfläche des rauhen endoplasmatischen Retikulums in P gegenüber A zu. In A entwickeln sich mehr Microvilli, ein extensiveres basales Labyrinth und ein deutliches glattes endoplasmatisches Retikulum. Vergrößerte Cytoplasmavolumina vor allem in den P-Zellen werden 24 Std. nach dem 1. B.M. gefunden (Stadium 3). Parallel dazu erreichen die Volumina der Organellen und/oder ihre Membranoberflächen ebenfalls Maximalwerte. Diese Vergrößerung des gesamten Zell-apparates läßt den Schluß zu, daß während der Blutverdauung die Funktionskapazität des Mitteldarmes erhöht ist. Basierend auf den quantitativ ultrastrukturellen Unterschieden zwischen den Zellen von A und P wurde postuliert, daß dem vorderen Abschnitt des Mitteldarms verstärkte Absorptionsfunktionen zukommen. Dem hinteren Abschnitt hingegen wurden gesteigerte Protein-syntheseleistungen im Zusammenhang mit der Bildung von Verdauungsenzymen zugeordnet. Die vorliegenden Resultate wurden an einem, in Beziehung auf seine Ernährung, spezialisierten Insekt gewonnen (Blutverdauung). Trotzdem scheint die postulierte Zuordnung von Funktionen zu bestimmten Mitteldarmzonen mit dem “secretion—absorption”-Modell (Berridge, 1970) übereinzustimmen.
    Notes: Summary The ultrastructure of the midgut of Aedes aegypti females was investigated by means of morphometric techniques. The interest was focussed on quantitative differences in the composition of epithelial cells between the anterior (A) and posterior (P) part of the midgut. The aim was to attribute defined functions to each of these 2 parts. 5 different physiological stages were compared: 1 = immature female; 2 = ready for first blood meal (b.m.); 3 = digestion of b.m.; 4 = ready for 2nd b.m.; 5 = aging female. Whereas in stage 1, when the gut has not yet reached a functional state the epithelial cells of A and P resemble each other, distinct differences develop in subsequent stages. Generally the cell volume and the nuclear-cytoplasmic ratio become higher in P than in A. Concomitantly the mitochondrial content and the surface area of the rough endoplasmic reticulum are more prominent in P than in A. On the other hand more microvilli, a more extensive basal labyrinth and a well developed smooth endoplasmic reticulum are present in A. Enlarged cytoplasmic volumes, especially high in P, are found 24 h after the first b.m. (stage 3). In accordance with this increase the volume of organelles and/or their membrane surface areas also reach maximal values. This augmentation of the metabolic cell apparatus suggests that during blood digestion the whole organ develops an increased functional capacity. From the quantitative structural differences in A and P we concluded that the A-part of the midgut is especially involved in absorption. To the P-part more protein synthesis may be attributed, thus indicating an enhanced formation of digestive enzymes. Although this study deals with a rather specialised insect (blood digestion), it appears that our hypothesis attributing functions to defined midgut zones, agrees to a certain extent with the “secretion-absorption-model” of Berridge (1970).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224209
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  • 117
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on the development of the nerve supply in the rabbit pars intermedia (1974)
    Springer
    Cell & tissue research 152 (1974), S. 113-128 
    Details
    ISSN: 1432-0878
    Keywords: Rabbit pars intermedia ; Ultrastructure ; Nerve terminal ; PI-type glandular cell ; ACT-type cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By electron microscopy three types of nerve terminals have been identified in adult rabbit pars intermedia (PI). The characteristics of these are described and their development traced. The distribution of nerve terminals and neurons within the PI is documented. In particular the association between types of nerve terminal and the different glandular cells is shown to be precise and selective. Direct innervation of the ACT-type cells in the rabbit PI is described for the first time. The author is particularly grateful to Dr. J. W. B. Bradfield for help in the preparation of this paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224214
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  • 118
    Electronic Resource
    Electronic Resource
    The fine structure of the larynx muscles in female tree frogs, Hyla a. arborea L. (Anura, Amphibia) (1974)
    Springer
    Cell & tissue research 152 (1974), S. 185-191 
    Details
    ISSN: 1432-0878
    Keywords: Laryngeal muscles ; Female tree frog, Hyla arborea arborea (L.) ; Fine structure ; Motor endplates ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larynx musculature of female tree frogs is very poorly developed compared with that of males. This is probably due to the fact that they are less used; female tree frogs do not produce mating calls. The larynx muscles of the female are composed of fibers with small, medium, and large cross-sections. The distribution of the motor end plates varies correspondingly: in regions with fibers of very small diameter the density of synapses is about 33 times greater than in regions with large fibers. There is also a difference in fine structure between male and female laryngeal muscles. The muscles of females comprise red fibers, white fibers, and various transitional types. The arrangement of the triads and their number per sarcomere is the same in all fiber types. All fibers contain about the same amounts of glycogen, but the fat content varies widely among the different types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224694
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  • 119
    Electronic Resource
    Electronic Resource
    Estrogen-induced transformation of somatotrophs into mammotrophs in the rat (1974)
    Springer
    Cell & tissue research 152 (1974), S. 229-238 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland (rat) ; Estrogen administration ; Somatotroph and mammotroph ; Ultrastructure ; Radioautography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the normal male rat pituitary tritiated thymidine labeled mainly STH cells (somatotrophs), no labeled prolactin cell was found. Following estradiol treatment for 21 days tritiated thymidine labeled mainly prolactin cells (mammotrophs). To determine the origin of these mammotrophs tritiated thymidine was given before the estradiol treatment started, thus labeling many somatotrophs. After 21 days of estradiol, out of 42 labeled cells, 14 were mammotrophs and 13 were somatotrophs; these results suggest that there might be a true transformation of somatotrophs into mammotrophs under the influence of estradiol or that there exist two types of somatotrophs: 1) a committed somatotroph which is not transformed by estrogen treatment, and 2) an uncommitted mammosomatotroph, which under normal conditions bears the features of a somatotroph, but which transforms into a mammotroph under the influence of estradiol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224697
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    A note on the ultrastructure of the Octopus olfactory organ (1974)
    Springer
    Cell & tissue research 152 (1974), S. 253-258 
    Details
    ISSN: 1432-0878
    Keywords: Olfactory organs ; Cephalopods ; Chemoreception ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the so-called olfactory organ of Octopus vulgaris has been investigated. Electron microscopy shows the superficial layer of the epithelium to consist mainly of cells bearing microvilli. Below this, often very deeply, lie very many large cells, which bear numerous cilia. These cells open to the surface via narrow processes running between the epithelial cells. Although details of their innervation have yet to be established the large cells are assumed to be receptors and these findings are interpreted as evidence that this organ is indeed chemosensory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224699
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    An ultrastructural study of the subcommissural organ cells of the African clawed toad, Xenopus laevis (1974)
    Springer
    Cell & tissue research 152 (1974), S. 239-252 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Xenopus laevis ; Histochemistry ; Subcommissural organ (SCO)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural features of the subcommissural organ (SCO) cells in larvae (stages 56–58, according to Nieuwkoop and Faber, 1956), toadlets (3 months after metamorphosis) and older toads (2-year old) of Xenopus laevis are described. Several age-related morphological differences in the endoplasmic reticulum (ER) of the SCO cells have been found. In old toads the rough ER assumes a special “ladder-like” membrane configuration in its cisternal lumen. By means of the periodic acid-chromic acid-silver methenamine (PA-CrA-SM) method, complex carbohydrates are detected electron microscopically in the SCO cells. Positive reactions take place in the cell adhesive apparatus, the secretory granules, part of the Golgi complex, and the intracisternal “ladder-like” structure. Passing through the Golgi complex, the secretory products mature into the secretory granules by association of their proteinaceous component with polysaccharides. The majority of the secretory granules are released from the apical cell surface by means of reverse pinocytosis, while the rest are released through the basal process into the blood circulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224698
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  • 122
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    Function and ultrastructure of the nephridium of Hirudo medicinalis L. (1974)
    Springer
    Cell & tissue research 152 (1974), S. 385-401 
    Details
    ISSN: 1432-0878
    Keywords: Nephridium ; Hirudo medicinalis ; Central canal ; Urinary bladder ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei elektronenmikroskopischer Untersuchung des nephridialen Zentralkanals von Hirudo medicinalis L. können mehrere Kanalabschnitte unterschieden werden, die zum Teil frei im Bindegewebe liegen, wie der Anfangs-, der intermediäre und der Endkanal, oder aber durch mehr oder weniger enge Verzahnung mit Canaliculuszellen verbunden sind (innerer und weiter Kanal). Strukturen, die mit transzellulärem Ionentransport in Beziehung gebracht werden können — ikrovilli und basale Zellmembraneinfaltungen — finden sich in allen Kanalabschnitten. Während im Verlauf des Zentralkanals die Oberflächenvergrößerung durch Mikrovilli ziemlich konstant bleibt, findet sich in den Kanalabschnitten, die ausschließlich an Bindegewebe grenzen, eine besonders auffällige und signifikante Zunahme der basalen Oberflächenvergräßerung durch Zellmembraneinfaltungen. Es werden mögliche Besonderheiten im Reabsorptionsmechanismus diskutiert: Möglicherweise läuft zwischen dem Epithel des inneren und des weiten Kanals einerseits und den angrenzenden Canaliculuszellen andererseits ein Kreislaufprozeß für Ionen (recycling) ab.
    Notes: Summary The central canal and the urinary bladder of the leech Hirudo medicinalis (L.) were studied by electron microscopy. The central canal consists of several different parts: the initial, intermediate and terminal canal which border only on connective tissue, and the inner and the wide canal which on the other hand are closely connected to the canaliculus cells which produce the primary urine. Structures related to transcellular transport of solutes such as microvilli and basal plasma membrane infoldings in association with mitochondria have been found in all parts of the central canal. Evidence has been obtained that the surface enlargement by basal plasma membrane infoldings increases from the proximal to the distal parts of the central canal while the luminal surface enlargement remains nearly constant. The increasing basal surface enlargement is especially obvious in those parts of the central canal which border only on connective tissue. The mechanism of reabsorption is discussed with regard to physiological data so far available. A recycling process for solutes may take place between the epithelium of the inner and the wide canal on one hand and the bordering canaliculus cells on the other hand.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223956
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    Ultrastructure of the nucleus of human sertoli cells in normal and pathological testes (1974)
    Springer
    Cell & tissue research 152 (1974), S. 467-475 
    Details
    ISSN: 1432-0878
    Keywords: Sertoli cell ; Human testis ; Nucleolus ; Nuclear bodies ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the nucleus of human Sertoli cells has been studied in testicular samples from normal adults and patients with hypospermatogenesis or absence of the germinal cell line (Sertoli cell only syndrome). In all cases the ultrastructure of the nuclear structures was alike. The nucleus is irregularly shaped and its membrane presents numerous pores. The inner aspect of the nuclear membrane is electron dense due to the presence of a fibrous lamina. The outer aspect presents a concentric arrangement of 50 Å cytoplasmic filaments. The chromatin is rather dispersed. Some perichromatin granules are found occasionally. The nucleolus is characteristic of human Sertoli cells and displays three clear components. In addition, sphaeridia of at least two principal morphological types were found. Their significance in the cell metabolism as well as relationship to either the nucleolus or the nuclear DNA are discussed. The need for further investigation on the functional meaning of the nuclear organelles of human Sertoli cells is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218932
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    Ovulation and the mechanism of follicle rupture (1974)
    Springer
    Cell & tissue research 153 (1974), S. 1-14 
    Details
    ISSN: 1432-0878
    Keywords: Graafian follicle (Rabbit) ; Granulosa cells ; Ovulation ; Basement mem-brane ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Membrana granulosa in rabbit Graafian follicles was studied at accurately determined times after an ovulatory dose of human chorionic gonadotrophin (HCG). At 4 and 6 hrs after injection of HCG the granulosa cells were slightly dissociated around the whole follicle. So-called abutment nexuses (gap junctions) had decreased and continued to do so up to ovulation. At 8 hrs after HCG, membrana granulosa had thinned out apically and cell dissociation was even more evident in all parts of the follicle. Granulosa cell projections through the basement membrane were found, and, closer to the time of ovulation, more and larger granulosa cell protrusions penetrated the partly fragmented basement membrane. At 8 hrs spherical inclusions in the granulosa cells, corresponding to so-called annular nexuses, were significantly more numerous than before injection of HCG; the relative amount had more than doubled. Later, the number of annular nexuses decreased. The significance of annular nexuses and their variations is discussed. The decrease in the abutment nexuses probably means a decrease in cohesive force between the granulosa cells and facilitates follicle expansion; moreover, the simultaneous changes in the basement membrane, with more or less open channels into the antrum the last few hours before ovulation, presumably, permit rapid follicle growth by influx of fluid as soon as increased distensibility of the follicle wall allows further expansion without increase in pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225441
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    Ovulation and the mechanism of follicle rupture (1974)
    Springer
    Cell & tissue research 153 (1974), S. 31-44 
    Details
    ISSN: 1432-0878
    Keywords: Graafian follicle (Rabbit) ; Ovulation ; Capillaries ; Intercellular junc-tions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rabbit Graafian follicles are encircled by a capillary network between the theca interna and the avascular membrana granulosa. After injection of an ovulatory dose of human chorionic gonadotrophin (HCG) the theca interna cells showed an increase in the amount of smooth endoplasmic reticulum, lipid droplets and mitochondria with tubular cristae. In addition, considerably more junctions, similar to the abutment nexuses of granulosa cells were found; annular nexuses also appeared. At 4 hours after injection of HCG a prominent oedema was evident in the theca interna layer, particularly in the apical region. Small fenestrations in the endothelium of the blood capillaries increased in amount after HCG injection, and close to the time of ovulation, large gaps or perforations, 1–3 μ in diameter, were found in the thin, distended part of the endothelial cells. The surrounding basement membrane became fragmented and partly lost, so that a seemingly free passage from the capillary lumen to the interstitium was eventually established. Leakage of fluid, causing interstitial oedema, presumably proceeds until the pressure in the pericapillary interstitium has risen to the pressure in the capillaries. Some hours before and up to ovulation the pericapillary interstitium has also broad communications with the cavity of the follicles. Therefore, both pressure and fluid can be passed from the capillaries-via the interstitium-to the follicle antrum. However, influx of fluid with subsequent follicle expansion and ovulation-at constant pressure-does not occur until the tensile strength of the follicle wall has decreased.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225443
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    Special muscle cells and their innervation in the mammalian small intestine (1974)
    Springer
    Cell & tissue research 153 (1974), S. 63-77 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Intestine ; Afferent fibres ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innermost layer of the circular musculature of the ileum of the guinea-pig, mouse, rat, rabbit, cat and dog is made of special small and dark muscle cells (sd cells), which can be identified by light and electron microscopy. These cells have a higher surface to volume ratio than ordinary muscle cells. They show all the organelles of smooth muscle cells and are in close relationship with a great number of extrinsic and intrinsic nerve fibres. They send numerous thin cytoplasmic processes towards the bulk of the circular layer, but nexuses between the sd cells and ordinary muscle cells are not found. It is suggested that some of the nerve fibres in this part of the circular layer are motor, setting the sd cells to a given length, and some are afferent in luminal pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225446
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    The ultrastructure of the yolk nucleus during early cleavage of Nassarius reticulatus L. (Gastropoda, Prosobranchia) (1974)
    Springer
    Cell & tissue research 153 (1974), S. 79-88 
    Details
    ISSN: 1432-0878
    Keywords: Yolk nuclei ; Nassarius reticulatus ; Cleavage ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Dotterkerne kommen in allen Blastomeren des 4- bis 16-Zellstadiums von Nassarius vor. Sie haben überwiegend kugelige Gestalt und liegen kernnah zwischen Kern und apikalem Plasmalemm. Feinstrukturell sind sie erstaunlicherweise nicht einheitlich aufgebaut, sondern treten in zwei Typen auf: Typ I besteht aus einer relativ kompakt erscheinenden kugeligen Ansammlung von Mitochondrien. Die Mitochondrien liegen in einer dichten, teils granulären, teils fibrillären intermitochondrialen Substanz eingebettet. Typ II besteht aus einer ebenfalls kugeligen Ansammlung vieler kleiner radiär angeordneter Golgi-Stapel, welche in der gleichen dichten, teils granulären, teils fibrillären Substanz liegen wie die Mitochondrien von Typ I. Die Funktion beider Typen von Dotterkernen wird diskutiert. Sicherlich haben sie nichts mehr mit der Dottersynthese zu tun wie möglicherweise die Dotterkerne der Oocyten, doch gibt es bisher auch keine Anzeichen dafür, daß sie bevorzugt am Dotter- oder Lipidabbau beteiligt sind.
    Notes: Summary In all blastomeres of Nassarius from 4- to 16-cell stage yolk nuclei occur. Most of them are spherical bodies, lying juxtanuclearly between the nucleus and the apical plasmalemma. Strangely they are not ultrastructurally uniform but fall into two categories (Fig. 5): Type I is a massive spherical accumulation of mitochondria embedded in a dense intermitochondrial substance, which appears to contain both granules and filaments. Type II is a ball of radially arranged small Golgi stacks clustered around a centre of Golgi vesicles and other organelles embedded in a ground cytoplasm structurally similar to the intermitochondrial substance of type I. The function of both types of yolk nuclei is unknown. These segmentation yolk nuclei have nothing to do with yolk synthesis any more. On the other hand there are no indications that yolk nuclei occurrence is correlated with the break-down of yolk because neither lipid droplets nor protein yolk granules are observed in or beside the yolk nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225447
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    Catalase-like crystals in parathyroid gland cells of Rana temporaria L. (1974)
    Springer
    Cell & tissue research 153 (1974), S. 167-173 
    Details
    ISSN: 1432-0878
    Keywords: Parathyroids ; Rana temporaria ; Crystals ; Ultrastructure ; Catalase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Crystalline inclusions in parathyroid gland cell nuclei of Rana temporaria were studied by electron microscopy using a specimen tilting stage. Images were analysed by optical diffraction. Results were compared with X-ray and electron microscopic data of trigonal bovine liver catalase to which a striking resemblance of the inclusions was found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226605
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    Connections between adjacent retinula cell columns in the eye of Ephestia kuehniella Zeller (Lepidoptera, Pyralididae) (1974)
    Springer
    Cell & tissue research 153 (1974), S. 189-193 
    Details
    ISSN: 1432-0878
    Keywords: Eyes ; Retinula ; Ephestia kuehniella ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Im Auge von Ephestia kommen Kontakte zwischen den Zellen benachbarter Retinulae vor. Diese Kontakte finden sich am häufigsten in der Kernregion der Retinulazellen und können 2 oder mehr Retinulae miteinander verbinden. Da keine besonderen Membranstrukturen in der Kontaktzone beobachtet wurden und da andererseits die Retinulazellen auf diesem Niveau und weiter distal Pigmentgranula enthalten, scheinen diese Kontakte weder die Zellen chemisch bzw. elektrisch zu koppeln noch Reizlicht zu übertragen. Vielmehr wird angenommen, daß die Verlagerungen des Cytoplasmas bei Hell-Dunkeladaptation in benachbarten Retinulae durch die gegenseitige Berührung koordiniert werden.
    Notes: Summary Connections were found between retinula cells of adjacent retinula cell columns in the eye of Ephestia. The connections occur most frequently at the level of the retinula cell nuclei and may involve two or more retinula columns simultaneously. The absence of specialized structural modifications of the membranes and the presence of pigment granules at the level of the connections or distal to them indicates that these connections are probably not involved in selective chemical or electrical communication nor in light transmission. It is suggested that the connections may serve tactily to coordinate cytoplasmic movement in adjacent retinula columns during light-dark adaptation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226607
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  • 130
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    The distribution of synapses along the spinal cord of an amphibian embryo: An electron microscope study of junction development (1974)
    Springer
    Cell & tissue research 153 (1974), S. 227-244 
    Details
    ISSN: 1432-0878
    Keywords: Synapses ; Embryo (Xenopus laevis) ; Spinal cord ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rostro-caudal gradient of differentiation found in vertebrate embryos has been utilized to examine the sequence of synaptic junction development in the spinal cord of Xenopus laevis at a late embryonic stage. Uniform samples were taken at various points along the cord of a stage 27 embryo and examined in the electron microscope. The general ultrastructure of the cord demonstrated the rostro-caudal gradient of development. The sequence of synaptic junction development was like that in the cervical region (Hayes and Roberts, 1973). “Membrane-vesicle clusters” and “immature” synaptic junctions were found most caudally followed by synaptic junctions, first with cleft and subsynaptic membrane density, then with only cleft density and finally, most rostrally, with cleft, subsynaptic membrane, and subsynaptic cytoplasmic density. Mature synaptic junctions were found in increasing numbers from the mid to anterior trunk cord and could mediate alternating trunk flexions made by the embryos at this stage of development. “Membrane-vesicle clusters” were found near processes containing irregular vesicles and also near membrane outlines. These may be signs of dendritic growth. “Membrane-vesicle clusters” were also found in varicosities, facing the space around the spinal cord and in nerve fibres peripherally between the skin and myotomes. This suggests an association of early stages in synaptogenesis with axon growth. This and other possible inferences about axon and dendrite growth in relation to synaptogenesis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226611
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    The ultrastructure and source of nerve endings in the carotid body (1974)
    Springer
    Cell & tissue research 154 (1974), S. 303-319 
    Details
    ISSN: 1432-0878
    Keywords: Carotid body (Cat) ; Chemoreceptor ; Nerve endings ; Glossopharyngeal nerve ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of nerve endings in the cat carotid body was analyzed by serial section electron microscopy. In the normal animal, three types of intralobular endings can be recognized. The first type consists of large, calyciform endings which surround glomus cells. The second type includes small calyciform endings which arise from a thin axon and also contact glomus cells. Interstitial enlargements enveloped by sustentacular cells having no direct contact with glomus cells constitute a third type of nerve ending. Intracranial section of the glossopharyngeal nerve caused no change in the number or appearance of intralobular endings, indicating that they are afferent terminals. Stromal axons in the connective tissue of the carotid body may be autonomicfibers as indicated by their degeneration following removal of the superior cervical ganglion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223728
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    A time course study of water permeability and morphological alterations induced by mucosal hyperosmolarity in frog urinary bladder (1974)
    Springer
    Cell & tissue research 154 (1974), S. 345-356 
    Details
    ISSN: 1432-0878
    Keywords: Urinary bladder ; Frog ; Water permeability and Ultrastructure ; Hyperosmolarity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Resumé Certaines informations récentes (voir introduction) nous ont conduits à reconsidérer la possibilité que l'action de l'hormone antidiurétique sur les tissus épithéliaux puisse s'exercer au niveau des jonctions intercellulaires. Une étude comparative des cinétiques d'apparition des altérations ultrastructurales et des variations de perméabilité à l'eau a permis d'établir que les décollements de la “tight junction” provoqués par l'hyperosmolarité muqueuse apparaissent avant tout accroissement significatif du flux net d'eau et ne peuvent donc pas en être la conséquence. L'examen à haute résolution, par cryodécapage, de la structure de la “tight junction” montre l'apparition dans ces conditions de plages plus ou moins circulaires où la membrane présente un aspect lisse et apparemment distendu et où la structure typique de la “tight junction” a disparu. Ces modifications rétrocèdent après stimulation hormonale et ceci conduit à penser qu'elles ne sont pas impliquées dans la réspone hydrosomotique physiologique.
    Notes: Summary The role of the tight junction in the hydrosmotic response of the frog urinary bladder has been analysed by comparative kinetic studies and freeze etching examination. The comparison of the time course of the variations in transepithelial water net flux and of the alterations of tight junction ultrastructure in bladders exposed to mucosal hyperosmolar solutions shows that blisters are present in the tight junction before any increase in transepithelial water net flux. This indicates that the two phenomena are dissociated. In the same experimental conditions, freeze etching examination shows the presence in the tight junction of large areas of smooth and apparently stretched membrane where the typical network structure has disappeared. These alterations are reduced by further treatment with oxytocin and are probably not involved in the physiological hydrosomotic response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223731
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    Epitheliomuscular cells in Lingula unguis (Brachiopoda) and Branchiostoma lanceolatum (Acrania) (1974)
    Springer
    Cell & tissue research 154 (1974), S. 543-545 
    Details
    ISSN: 1432-0878
    Keywords: Epitheliomuscular cells ; Brachiopoda Lingula ; Acrania ; Branchiostoma ; Phylogeny ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epitheliomuscular cells largely corresponding to those of cnidarians have been found in the mesenteria of Lingula and in various coelomic channels of Branchiostoma. They are characterized by basal extensions containing thin and thick myofilaments. In Lingula they also bear an apical cilium.
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    URL: http://dx.doi.org/10.1007/BF00219673
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    Interdigitating reticulum cells in the human thymus (1974)
    Springer
    Cell & tissue research 155 (1974), S. 47-55 
    Details
    ISSN: 1432-0878
    Keywords: Thymus (human) ; Reticulum cells ; Thymus dependent region ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Seven thymuses from children between 1 and 12 years were examined by electron microscopy. Biopsies had been taken during surgical correction of congenital heart defects. In all cases we found interdigitating reticulum cells (IRC) in the medulla and inner cortex. These cells resembled the IRC which have been described previously in the thymus-dependent regions of the spleen and lymph node. They were characterized by an irregularly shaped nucleus, narrow cisterns of rough endoplasmic reticulum, and widespread interdigitation and invagination of the cell membrane. The surfaces of the IRC were in close contact with those of small lymphocytes, sometimes polysomal lymphatic cells, epithelial cells, and occasionally with those of lymphatic cells containing ergastoplasm. The IRC is apparently a specific cell of thymus-dependent regions. It may be that the IRC in the thymus, lymph node, and spleen contribute to the microenvironment needed for the differentiation of T-cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220283
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    Substrate-histochemical investigations and ultrahistochemical demonstrations of acid phosphatase in larval and prepupal salivary glands of Drosophila melanogaster (1974)
    Springer
    Cell & tissue research 155 (1974), S. 75-89 
    Details
    ISSN: 1432-0878
    Keywords: Salivary glands ; Drosophila ; larval and prepupal ; Electron microscopy ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A major function of the larval salivary glands of Drosophila melanogaster is known to be the production of a mucopolysaccharide that serves as an adhesive during puparium formation. In order to localize the mucosubstances during development substrate histochemical methods were used, and the site of acid phosphatase was demonstrated by the ultrahistochemical lead-salt method. It could be shown that the “glue”-granules in the corpus cells of larval salivary glands as well as the large secretion vacuoles in the prepupal corpus cells give a positive β-amylase-resistent PAS-reaction, which indicates neutral mucosubstances. Granular PAS-positive deposits in the larval and prepupal collum cells were reduced after preincubation with β-amylase and may represent glycogen, which has also been seen in electron micrographs of these cells. The Hale-reaction gave a weak indication that acid mucosubstances are present in the larval “glue” granules and in the large prepupal secretory vacuoles. After digestion of sialic acid with α-neuraminidase the weak indication was absent showing that the acid mucosubstances had been sialomucines. Ultrahistochemical demonstration of acid phosphatase indicated the presence of this enzyme in Golgi fields and lysosomal structures. Acid phosphatase seems to be missing in the large secretion vacuoles of the prepupal salivary gland. It is concluded, that the large vacuoles in the corpus cells of prepupal salivary glands represent a secretion product, obviously a mucosubstance. The lysosomal structures, containing acid phosphatase, may be accumulated in preparation for the autolysis of the gland which begins about two hours after the pupal moult, i.e. 15 hours after puparium formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220285
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    The ultrastructure of the organ of Bellonci of Carcinus maenas (Crustacea: Decapoda) (1974)
    Springer
    Cell & tissue research 155 (1974), S. 127-134 
    Details
    ISSN: 1432-0878
    Keywords: Organ of Bellonci ; Carcinus maenas (Crustacea, Decapoda) ; Sensory and secretory function ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organ of Bellonci of Carcinus maenas is made up of onion bodies and secretory cells. The onion body consists of a distal segment, of membranous whorls and granules, and a proximal nuclear cell body. They are joined by a modified double ciliary junction. Both a sensory and secrtory function is suggested. The secretory cells fall into two groups based on size, shape and organelles. Their presence suggests a secretory function to the organ of Bellonci.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220289
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  • 137
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    Synthesis and intracellular transport of proteins in the exocrine pancreas of the frog (Rana esculenta) (1974)
    Springer
    Cell & tissue research 155 (1974), S. 135-154 
    Details
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Frog ; Ultrastructure ; Intracellular transport ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The route by which secretory proteins are transported in the frog exocrine pancreas cell was investigated by an ultrastructural and electron microscope autoradiographic analysis of in vivo 3H-leucine labelled tissue. The ultrastructure of the cell is characteristic of serous epithelial cells and resembles that of mammalian exocrine pancreas cells very closely. Autoradiographic results revealed that the proteins, after being synthesized in the rough endoplasmic reticulum (RER), are transported through the Golgi cisternae to condensing vacuoles which subsequently change into secretory granules. The determination of the timing of this transport was complicated by a very slow turnover of leucine in the frog. Nevertheless, by a semi-quantitative approach, some time characteristics could be estimated: about 11 min after the onset of their synthesis the proteins enter the Golgi system, and about 25 min later the condensing vacuoles. Secretory granules become labelled between 60 and 120 min. These results are discussed, also in relation to the transport route and kinetics in mammalian tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221350
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  • 138
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    Primary tissue culture of human adult adrenocortical cells. Methodology and electron microscopic observations on ACTH-deprived and ACTH-treated cortical cells (1974)
    Springer
    Cell & tissue research 155 (1974), S. 155-180 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Man ; Primary cultures ; ACTH ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A method of primary tissue culture involving both disaggregation of cells by repeated exposure of small tissue fragments to a solution of trypsin, collagenase and hyaluronidase and explantation of the residual tissue fragments intermingled with isolated cells onto polyethylene discs, has been shown to be adequate for the prolonged maintenance (up to 30 days) in vitro of cells arising from decapsulated adult human adrenocortical tissue. The technique and its critical points are discussed. Adrenocortical cells were organized both as outgrowing columns from microexplants or as variously sized islets of monolayered cells. The ultrastructural features of ACTH-deprived adrenocortical cells (i.e., mitochondria with laminar cristae, endoplasmic reticulum mainly consisting of rough profiles, abundance of lipid droplets and β-glycogen particles) suggest that the cells dedifferentiate and retain practically no steroidogenic activity. After 2 days of ACTH-treatment, cultured parenchymal cells were found to be quite similar to the zona fasciculata elements of the normal human adrenal cortex. They were grouped in islets of about 50–100 cells. Rough endoplasmic reticulum had decreased, but smooth endoplasmic reticulum showed focal proliferation. The pleomorphic mitochondria with laminar cristae, transformed into a homogeneous population of round or ovoid mitochondria containing tubulo-vesicular cristae. Lipid droplets and glycogen particles were decreased in number. After 7 days of daily treatment with ACTH, the cortical elements, whose nucleus and cytoplasm seemed to be enlarged, were arranged in clusters formed by up to 300 monolayered elements, in which dividing cells were consistently observed. Their cytoplasm was filled with a meshwork of smooth reticulum tubules, in which scantly ribosome-studded profiles and occasional small stacks of granular cisternae were embedded. Mitochondria were similar to those of the 2 days ACTH-treated cultures. Lipid droplets and glycogen particles were absent. The functional significance of these structural changes as well as the possible mechanism underlying the differentiative effect of ACTH are discussed. Primary cultures of human adult adrenals are proposed as a new tool for studies into the physiopathology of the adrenocortical cells under carefully controlled experimental conditions. mis|It is a pleasure to acknowledge our thanks to Drs. F. Mantero and C. Eccher for kindly supplying the normal human adrenocortical tissue. Thanks are also due to Mr. G. Gottardo for his excellent technical assistance. mis|This work was partly supported by a contract with the CNR-Italy (C.T. 73.00663.04).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221351
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  • 139
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    Electronic Resource
    Localization of microfilaments in prolactin cells of the rat anterior pituitary gland (1974)
    Springer
    Cell & tissue research 155 (1974), S. 193-199 
    Details
    ISSN: 1432-0878
    Keywords: Microfilaments ; Prolactin cells ; Anterior pituitary ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prolactin cells from anterior pituitary glands of normal non-lactating female rats, and lactating animals, some of which were separated from their pups for 48 hours, were examined ultrastructurally for the presence of microfilaments. Microfilaments were found in specific intracellular locations in all cells examined. They were in association with the nuclear envelope, the Golgi complex, the endoplasmic reticulum, small vesicles of the endoplasmic reticulum, and secretory granules. The possible role of microfilaments in the movement of intracellular organelles is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221353
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  • 140
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    Electronic Resource
    An ultrastructural and electrophysiological study of the development of neuro-muscular junctions between previously dissociated foetal rat cells in vitro (1974)
    Springer
    Cell & tissue research 155 (1974), S. 269-282 
    Details
    ISSN: 1432-0878
    Keywords: Neuromuscular junctions ; Development in vitro ; Electron microscopy ; Electrophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of neuro-muscular junctions between previously dissociated foetal rat spinal cord and somatic muscle has been investigated. The first indications of junction formation, both ultrastructurally and electrophysiologically, were observed after circa 18 days in vitro. The junctions contained numerous vesicles, but no secondary folds were developed even after 6 weeks in culture, and synaptic densities were not well marked. Functional endplates were found, and action potentials, endplate potentials and miniature endplate potentials recorded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221359
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  • 141
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    Electronic Resource
    Ultrastructural changes in the tail muscles of anuran tadpoles during metamorphosis (1974)
    Springer
    Cell & tissue research 155 (1974), S. 321-336 
    Details
    ISSN: 1432-0878
    Keywords: Muscle fibres (Tadpole tail) ; Degeneration ; Macrophages ; Autophagic vacuoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This report describes histochemical and ultrastructural studies of tail muscles in tadpoles of Rana japonica and Rana catesbeiana during metamorphosis, this process being accompanied by degeneration of the tail. Degeneration of individual tail muscles does not occur at the same time; this is true for both the red and white muscle fibres. The initial phase of degeneration showed mesenchymal macrophages first invading the muscle fibres and then sending out many long cytoplasmic processes which split the fibres apart. The disappearance of myofibrils during degeneration proceeds along at least two different mechanisms even within a single muscle fibre. In one type, the Z-band becomes diffuse and then disappears, resulting in fragmentation of the myofibrils at the sites previously occupied by the Z-bands. The second pattern of degeneration is characterized by disappearance of the Z-band followed by a fanning out of the myofilaments not associated with fragmentation of myofibrils. As atrophy of muscle fibres proceeds, acid phosphatase activity is localized in the perinuclear sarcoplasm. Macrophages show more intense acid phosphatase activity than do the muscle fibres. The formation of autophagic vacuoles is described and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222809
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  • 142
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    Electronic Resource
    Pigment cell differentiation in albino goldfish (1974)
    Springer
    Cell & tissue research 155 (1974), S. 383-398 
    Details
    ISSN: 1432-0878
    Keywords: Pigment cells ; Melanin granules ; Pigment retina ; Albino goldfish ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structural differentiation of the retinal pigment epithelium of the albino goldfish (Carassius auratus) in several developmental stages and in the adult was studied. In the 5-mm larva, the retinal pigment cells contained granules whose cores are filled with conglomerates of electron-dense pigments, but they were never pigmented fully as in the control black moor goldfish. Most of the granules have a round or ovoid shape, but granules with an elongate, cigar-like form are occasionally observed. The internal membranous frame-work, which has been reported in unpigmented and lightly pigmented granules in melanocytes of other vertebrates, was rarely observed in the present study. The number of pigment granules increased during the early developmental stages, whereas they decreased conspicuously in the later stages. From these results, the function of one of the albino genes p, is discussed and the following three phenomena are attributed to it: the decrease in formation of cigar-shaped granules, the partial inhibition of pigmentation, and the disintegration of pigment granules during the larval and post-larval stages. In addition to the pigment granules, the differentiation and disappearance of other characteristic cytoplasmic organelles are described. The biological significance of the changes in many of these organelles remains in question.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222813
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  • 143
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    Electronic Resource
    The hypothalamo-hypophysial system of hypophysectomized rats (1974)
    Springer
    Cell & tissue research 155 (1974), S. 541-554 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysectomized rats ; Reorganized stalk ; Ultrastructure ; Salt load
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The reorganized stalk of hypophysectomized rats, either “intact” or subjected to a 6-day salt load, has been studied by light and electron microscopy. PAF-positive neurosecretory material is seen mainly in the periphery of the reorganized stalk, usually in 2–5 μ nerve swellings of animals operated two months before. Nerve swellings make contact with a dense capillary network. Three types of nerve fibres and their swellings are distinguished according to the size of elementary granules. Peptidergic A1 and A2 types contain granules with a maximum diameter of 170 and 130 nm respectively; monoaminergic B type fibres have granules of 100 nm in diameter. A1 type axonal swellings are the most numerous and can be tentatively divided into four subtypes according to their ultrastructure and relationships with capillaries and pituicytes. Swellings of types b and c, making direct contact with capillaries or pituicyte perikarya, usually contain few granules and numerous synaptic vesicles arranged frequently in clusters in the “active” zones. It is assumed that they are especially active in the release of peptide neurohormones. It is also hypothesized that in the hypophysectomized rats peptide neurohormones are released not only directly into the pericapillary space but also into the intercellular cleft, especially at sites of neuron-pituicyte junctions. Nerve swellings of type a, separated from the pericapillary space by thin pituicyte processes, usually contain numerous neurosecretory granules. It is suggested that vascular “end-feet” of pituicytes may somehow reduce neurohormone release. The depletion of PAF-positive material as well as the decreased granule content even after a salt load of only 1 per cent shows that the reorganized stalk is functional as a neurohaemal organ, but has a diminished hormone reserve. This, together with a primitive cytomyeloangioarchitecture speaks for morphological and functional imperfection of the reorganized stalk.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227014
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  • 144
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    Electronic Resource
    Lanthanum nitrate in a smooth muscle membrane system (1974)
    Springer
    Cell & tissue research 147 (1974), S. 157-161 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Iris ; Lanthanum nitrate ; Sarcoplasmic reticulum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Smooth muscle cells of the guinea-pig sphincter pupillae were fixed in the presence of 3% lanthanum nitrate. Although only small amounts of lanthanum were found in plasmalemmal vesicles, large deposits were present within a membrane system resembling sarcoplasmic reticulum. The significance of these findings is discussed in relation to the use of lanthanum nitrate as an extracellular tracer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582790
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  • 145
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    Electronic Resource
    Somatic spines in the supraoptic nucleus of the rat hypothalamus (1974)
    Springer
    Cell & tissue research 148 (1974), S. 203-211 
    Details
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Rat ; Supraoptic nucleus ; Ultrastructure ; Somatic spines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies of ultrathin serial sections of the perikarya and adjacent neuropil of neurons of the supraoptic nucleus (SON) of the adult male rat revealed varying forms of two types of somatic spines. One type forms synapses with axons passing the cell, the other, without synapses, appears to serve as a buttress or clasp for adjacent neuronal and glial processes. The synapse-bearing spines lack the usual spine apparatus but contain the flocculent substance often seen in spines. The other spines do not exhibit either of these structures. These somatic spines were also seen in Golgi impregnated preparations but the types could not be distinguished. Certain axons synapse either on a somatic spine of the perikarya or penetrate the glial sheath of the neuron and synapse, usually repeatedly, on the soma in an en passant manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224582
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  • 146
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    The innervation of the salivary gland of the moth, Manduca sexta (1974)
    Springer
    Cell & tissue research 148 (1974), S. 237-245 
    Details
    ISSN: 1432-0878
    Keywords: Salivary gland ; Innervation ; Insect ; Monoamines ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The salivary glands of the moth, Manduca sexta (Insecta: Sphingidae), are unlike most other salivary glands in that they are innervated from one source only. Vital staining of nerves with methylene-blue reveals numerous fine nerves extending to the glands from the oesophageal nerve, a part of the stomatogastric or visceral nervous system. Light and electron microscopy confirm that only the fluid-secreting cells, confined to a discrete region in these glands, are innervated. Axons with or without glial wrappings are found in intercellular spaces between fluid-secreting cells. Axons lacking a glial sheath contain, after glutaraldehyde-osmium tetroxide fixation, large granular and small agranular vesicles. In nerve endings in glands fixed with permanganate these smaller vesicles are granular, having the electron-dense cores characteristic of monoamine-containing neurons. These nerve endings with “synaptoid areas” are in close (“direct”) contact with the fluid-secreting cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224585
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  • 147
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    Electronic Resource
    Lanthanum binding by mouse cecal mucosa (1974)
    Springer
    Cell & tissue research 148 (1974), S. 309-311 
    Details
    ISSN: 1432-0878
    Keywords: Cecum ; Colon ; Lanthanum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After exposure of mouse cecal mucosa to lanthanum during primary fixation in glutaraldehyde, the metal was found as discrete particles covering microvilli and microorganisms, as a continuous layer outlining the lateral surfaces of epithelial cells, and as particles bound to collagen fibrils. The results suggest that lanthanum acts primarily as a stain of the surfaces of certain cells and extracellular structures, and to a lesser extent as an inert probe of the extracellular space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224259
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  • 148
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    Intraependymal cerebrospinal fluid contacting neurons and axon terminals on the external surface in the filum terminale of the carp (Cyprinus carpio) (1974)
    Springer
    Cell & tissue research 148 (1974), S. 359-370 
    Details
    ISSN: 1432-0878
    Keywords: Cerebrospinal fluid contacting neurons ; Filum terminale (Cyprinus carpio) ; Ultrastructure ; Synaptic semidesmosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small nerve cells are scattered among the ependymal cells of the central canal of the filum terminale in Cyprinus carpio. The dendrites of these neurons form bulb-like endings in the cerebrospinal fluid (CSF). These endings are similar to the CSF contacting dendritic terminals of the medulla oblongata and spinal cord. Therefore, we consider these nerve cells to belong to the CSF contacting neuronal system. The axons of these neurons enter the hypendymal fibrous zone where nerve processes of various calibres and axon terminals on dendrite-like profiles and sometimes on ependymal processes were found. In addition to cytoplasmic elements ordinarily present in nerve cells there are granulated vesicles of about 800 to 900 Å in diameter in the perikarya of the CSF contacting neurons. Axons containing synaptic and dense-core vesicles (diameter about 400 Å and 800 Å, respectively) build up synapses on the basal part of these neurons. The CSF contacting neurons described are dissimilar to the Dahlgren cells present in the urophysis and in the rostral part of the filum. In addition, we found axon terminals forming synaptic semidesmosomes on the basal lamina of the external surface of the filum. At some places these terminals are numerous, building up primitive median eminence-like areas on the surface of the filum. In addition to synaptic vesicles these terminals contain numerous granulated vesicles of 800 Å. The axons forming these terminals are supposed to originate from the CSF contacting neurons. The presence of special nerve terminals on the external surface furnishes morphological evidence for the passage of substances from the nervous tissue into the external CSF space at the level of the filum terminale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224263
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  • 149
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    Microglia and reactive “M” cells of degenerating central nervous system: Does similar morphology and function imply a common origin? (1974)
    Springer
    Cell & tissue research 148 (1974), S. 477-491 
    Details
    ISSN: 1432-0878
    Keywords: Microglia ; “M” cells ; Gliogenesis ; Neuropathology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy of subependymal cells and microglia in rat neonatal spinal cord reveals the latter to be a distinctive group of non-neuronal elements characterized by pronounced heterochromatin nuclei, many free ribosomes and rosettes, hour-glass shaped mitochondria, a moderately dense, granular cytoplasmic matrix, lipid vacuoles and a wide variety of lysosomes. Some examples are elongated and ameboid in appearance or may contain phagocytic vacuoles. Transitional forms between subependymal cells, or any other nonneuronal forms, and microglia were not observed. Ultrastructural features displayed by microglia are also strikingly characteristic of the “M” cells (Matthews and Kruger, 1973a, b) encountered in zones of thalamic degeneration two to three weeks following cortical ablation of adult rabbits. During the first and second postoperative weeks, “M” cells closely resemble the agranular leukocytes accumulating in the perivascular space of vessels coursing within the zones of degeneration. This fact, together with documentation of penetration of the vascular external lamina by elements of similar morphology, indicates a mesodermal origin for some “M” cells. The microglia of normal CNS and “M” cells of pathologic neural tissue are sufficiently similar, both in morphology and apparent function, to warrant consideration of a mesodermal origin for the microglia of neonatal CNS and a number of criteria to substantiate this concept are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221932
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  • 150
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    Electronic Resource
    Early axonal changes following lesions of the dorsal columns in rats (1974)
    Springer
    Cell & tissue research 149 (1974), S. 1-20 
    Details
    ISSN: 1432-0878
    Keywords: Axon sprouts ; Regeneration ; Dorsal column lesion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A graded series of changes occur around lesions to the central nervous system. In the present investigation three zones were distinguished caudal to a lesion of the dorsal columns in the rat, In Zone I near the lesion, necrosis and cellular disintegration are followed by phagocytosis, and the development of a loose connective tissue matrix. Here Schwann cells proliferate and envelope axon sprouts in a similar fashion to those in developing of regenerating peripheral nerve. Zone II includes the proximal segment of nervous tissue containing normal appearing axons in continuity with parent nerve cells. Here an initially severe edematous condition is followed by growth and proliferation of astrocytes. Axon sprouts are present in the transitional Boundary Zone the first day following a lesion. They continue to grow and are most numerous at one week. By two weeks axons have apparently disappeared from many parts of Zone I and degeneration of parent axons and retraction clubs is advanced in Zone II. The reasons for axon involution are not known but do not appear to be related to the development of a glial scar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209047
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  • 151
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    On the interdigitating cells in the thymus-dependent area of the rat spleen: A relation between the mononuclear phagocyte system and T-lymphocytes (1974)
    Springer
    Cell & tissue research 148 (1974), S. 247-257 
    Details
    ISSN: 1432-0878
    Keywords: Spleen (Rat) ; Periarteriolar lymphocytic sheath ; Mononuclear phagocyte system (MPS) ; Thymectomy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light- and electron microscopic studies reveal that the peri-arteriolar lymphocytic sheath of the rat spleen can be divided into two areas. The central area contains small lymphocytes, interdigitating cells (IDC, light staining cells with extensive cytoplasmic interdigitations) and some scattered reticulum cells. The peripheral area contains a mixed population of lymphocytes and circumferentially oriented reticulum cells. It is shown that only the central area of the peri-arteriolar lymphocytic sheath is thymus-dependent. In neonatally thymectomized rats, before interdigitating cells appear, monocytes and promonocytes reside in this area. It is suggested that the IDC are part of the mononuclear phagocyte system (Langevoort et al., 1970). They probably form the micro-environment necessary for the differentiation and proliferation of T-cells. The analogies between IDC, epithelioid cells and the macrophages in the migration inhibition test are discussed. The hypothesis is put forward that these cells are similar in ultrastructural and functional aspects because all three are macrophages under the influence of humoral factors from T-cells, such as migration inhibition factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224586
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  • 152
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    Effects of antibiotics on intracellular symbiotes in the pea aphid, Acyrthosiphon pisum (1974)
    Springer
    Cell & tissue research 148 (1974), S. 287-300 
    Details
    ISSN: 1432-0878
    Keywords: Symbiotes ; Aphids ; Antibiotics ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of penicillin and chlortetracyline HCl on the fine structure of the intracellular symbiotes of the pea aphid were studied in an attempt to remove the symbiote population. High penicillin concentrations, 1% and 0.1%, caused symbiote breakdown but were toxic and/or repellent to the aphids; at 0.1% specific effects were observed on the symbiotes' cell walls. After the use of 0.01% penicillin in the aphid diet, the symbiotes had abnormal cell walls and were abnormally dilated; however, symbiote division and transmission from one aphid generation to the next seemed unaffected and the aphids appeared normal. Aphids fed 0.1% chlortetracycline failed to reproduce. After 7 days, their symbiotes were found to break down at a high rate but aphid mitochondria were also adversely affected at this stage. Following 0.002% chlortetracycline, the aphids produced aposymbiotic progeny with apparently normal mitochondrial populations; these larvae failed to develop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224257
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  • 153
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    A comparative ultrastructural study of the pars tuberalis of various mammals, the chicken and the newt (1974)
    Springer
    Cell & tissue research 148 (1974), S. 313-329 
    Details
    ISSN: 1432-0878
    Keywords: Pars tuberalis ; Mammals ; Chicken ; Newt ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars tuberalis of the rat, mouse, garden door mouse, European hamster, cat, cattle, chicken and newt is composed of two main cell types: specific secretory cells and follicular cells. The specific cells are characterized by comparable morphologic features in the investigated species, despite differences in the diameter of the secretory granulated vesicles; the ultrastructural morphology of these cells is different from that of any of the known cell types of the adenohypophysis. The follicular cells are devoid of secretory granules, they do not only line the numerous follicular cavities of the pars tuberalis but may also be found in the periphery of the cell cords (border cells). In addition, gonadotrophic cells are found; they predominate in the distal portion of the pars tuberalis and are definitely activated by castration or hypophysectomy. Experimental interventions on most of the major endocrine systems did not cause any noticeable ultrastructural changes in the specific cells. It appears certain that the pars tuberalis secretes a specific hormone whose function remains to be determined.
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    URL: http://dx.doi.org/10.1007/BF00224260
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  • 154
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    Morphogenesis of the syncytium in the mouse placenta (1974)
    Springer
    Cell & tissue research 148 (1974), S. 381-396 
    Details
    ISSN: 1432-0878
    Keywords: Placenta ; Mouse ; Syncytium ; Morphogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'origine embryologique des constituants cytologiques de la barrière placentaire chez la Souris a été mise en évidence du 8ème au 11éme jour de la gestation et la séquence des phénomènes favorisant la formation d'un syncytium trophoblastique, précisée. La barrière placentaire trilaminaire a une double origine: la couche interne provient du trophoblaste chorionique, la couche médiane syncytiale comme la couche externe dérivent du trophoblaste ectoplacentaire. Le stimulus initial de la différenciation semble résulter au 9ème jour du contact entre le trophoblaste chorionique et le mésoderme allantoïdien. Quelques heures après, on observe la réaction des cellules chorioniques, caractérisée par une augmentation importante des nucléoprotéines cytoplasmiques, puis l'apparition de globules lipidiques et enfin des propriétés de motilité. Ces cellules établissent des jonctions complexes avec le trophoblaste ectoplacentaire indifférencié qu'elles côtoient. En même temps, le métabolisme nucléaire de ces cellules ectoplacentaires semble modifié. Ultérieurement, au 10éme jour de la gestation, la disparition des membranes plasmiques latérales de ces cellules, conduit à la formation d'un syncytium par fusion de cellules au même stade d'évolution.
    Notes: Summary The morphogenesis of the different layers forming the mouse placental barrier is described during the 8th to 11th day of gestation. The timing and events leading to the formation of the syncytiotrophoblast are analyzed. Two different processes lead to the formation of the hemotrichorial placental membrane: the internal layer is formed by the chorionic trophoblast, both the intermediate syncytial layer and the external cytotrophoblast layer are derived from the ectoplacental trophoblast. The differentiation of the placental barrier begins on the 9th day of gestation by the establishment of contact between the chorionic trophoblast and the allantoic mesoderm. A few hours later, the chorionic cells show a considerable increase in cytoplasmic nucleoproteins and lipids and become ameboid. Complex cell-junctions differentiate between these chorionic cells and the adjacent ectoplacental trophoblast. On the 10th day of gestation the lateral cytoplasmic membranes disappear leading to the formation of a syncytium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224265
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  • 155
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    On the sexual segment of the kidney in the snake (Natrix natrix) (1974)
    Springer
    Cell & tissue research 148 (1974), S. 417-429 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Sexual segment ; Natrix natrix ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sexual segment of the kidney of Natrix natrix has been investigated cytochemically, light microscopically and ultrastructurally. The sexual segment, which seems to be an important accessory sexual organ, has a single layer of a columnar epithelium. The epithelial cells are filled with large secretion granules of a wide range of electron densities. Cytochemical reactions for neutral and acid mucosubstances are negative, but the cells show a strong positive staining for phospholipids. Within the cells of the sexual segment we have localised by histochemical means several hydrolases and oxydoreductases, which reflect enzyme activities of the glycolytic pathway, the citrate cycle, and related metabolic pathways. The activities of the hydrolytic enzymes acid phosphatase, acetylcholinesterase and indoxylacetate esterase are remarkably high within the epithelial cells. Furthermore it was found that the sexual segment tubules possess contractile elements which extends over the basal surface of the epithelial cells. These contractile cells exhibit a very high activity of alkaline phosphatase. Single unmyelinated axons are located between the contractile elements and the basal lamina of the sexual segment cells. The functional significance of the sexual segment structures is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224268
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  • 156
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    Specific organization of intracytoplasmic filaments in the dog testicular interstitial cell (1974)
    Springer
    Cell & tissue research 148 (1974), S. 493-497 
    Details
    ISSN: 1432-0878
    Keywords: Testicular interstitial cells ; Dog ; Filaments ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the dog testicular interstitial cells the cytoplasmic filaments are occasionally arranged in large bundles piled closely in an extensive area adjacent to the Golgi region in the cytoplasm. Some of the large bundles show conspicuous circular or spiral configurations which are composed of elaborate arrangements of both circular and longitudinal filaments and accompany tubules of agranular endoplasmic reticulum running parallel to the longitudinal filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221933
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  • 157
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    Rhombic dodecahedral secretory granules in glucagon producing islet cells (1974)
    Springer
    Cell & tissue research 148 (1974), S. 561-563 
    Details
    ISSN: 1432-0878
    Keywords: Pancreatic islets ; Xiphophorus helleri ; A2-Granules ; Crystalline structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By tilting experiments in the electron microscope evidence was found for crystalline islet A2-granules of Xiphophorus helleri H. to be rhombic dodecahedral and thus to belong to the cubic system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221939
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  • 158
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    Reconstitution of the thymus dependent area in the spleen of lethally irradiated mice (1974)
    Springer
    Cell & tissue research 149 (1974), S. 43-60 
    Details
    ISSN: 1432-0878
    Keywords: Spleen ; Thymus dependent area ; Periarteriolar lymphatic sheath (PALS) ; Interdigitating cell (IDC) ; T-lymphocyte ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To study the submicroscopical morphology of the microenvironment for T-lymphocytes in the spleen, mice were lethally X-irradiated and injected intravenously with syngeneic thymocytes. 24 hours after cell transfer, small lymphocytes occurred in the thymus dependent area of the spleen: the periarteriolar lymphatic sheath (PALS). They localized preferentially around a special type of mononuclear phagocyte, the Interdigitating Cell (IDC), which is considered to be characteristic for thymus-dependent areas in peripheral lymphoid organs. A close cell contact between both cell types was observed: small lymphocytes protruded into the cytoplasm of the IDC by means of fingerlike protrusions. This type of cell contact seems to induce blast transformation of the lymphoid cells which resulted in the formation of medium sized T-cells. In a control experiment, spleen cells from thymectomized, X-irradiated and bone marrow reconstituted mice were injected intravenously into lethally X-irradiated recipients. These B-lymphocytes, however, were not found to be localized around IDC. They preferentially formed primary follicles at the periphery of lymphocyte-depleted thymus dependent areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209049
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  • 159
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    Altered formation of dye-induced lysosomes in mouse fibroblasts due to growth in “deficient” media (1974)
    Springer
    Cell & tissue research 147 (1974), S. 219-235 
    Details
    ISSN: 1432-0878
    Keywords: Lysosomes ; Mouse fibroblasts ; Dye treatment ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mouse fibroblasts were grown in a ‘deficient’ medium consisting solely of Hank's salt solution. Treatment of cells after 48 hours in deficient medium with the cationic dye, mepacrine, resulted in an altered formation of lysosomes. Cells grown in full medium form dense, multi-vesiculated lysosomes in response to mepacrine. Cells grown in deficient medium form large electron lucent vacuoles containing peripherally located dense globules. The significance of the observations in relation to the deficiency of the medium is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582797
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  • 160
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    The ultrastructure of the fenestra dorsalis of the syncarid crustaceans Allanaspides helonomus and Allanaspides hickmani (1974)
    Springer
    Cell & tissue research 147 (1974), S. 335-351 
    Details
    ISSN: 1432-0878
    Keywords: Fenestra dorsalis ; Allanaspides ; Syncarida ; Ion transport ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The genus Allanaspides (Crustacea, Syncarida) is characterised by a conspicuous modification of the cephalo-thoracic tergite, the fenestra dorsalis. The ultrastructure of the fenestra dorsalis was examined in both known species of Allanaspides. The organ is separated from surrounding tissue by a clearly demarcated transition zone in which the cuticle thickens and looses its normal laminated structure. In the cells of the fenestra dorsalis, three regions may be distinguished. The apical region has an abundance of long invaginations, often packed closely together. The invaginations possess numerous microtubules plus numerous mitochondria whose membranes are closely associated with the invaginated membranes. Both microtubules and mitochondria are aligned in the same direction as the invaginations. The middle region of the cells contains many intracellular vacuoles in Allanaspides hickmani whilst in Allanaspides helonomus the same region contains extensive extracellular spaces. The basal region of the cells is marked by deep infoldings and an abundance of mitochondria. Microtubules are common and these, together with the mitochondria, are aligned along the direction of the infoldings. Adjacent cells are linked by frequent septate junctions. The fine structure of fenestra dorsalis tissue indicates an active participation in ion and/or water movement. However, in contrast to other crustacean tissues known to be involved in this function, it is postulated that the fenestra dorsalis of Allanaspides provides a two-stage transport system, in which “mitochondrial pumps” are present on both the inner and outer cell surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307469
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  • 161
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    Investigations of ageing in costal and tracheal cartilage of rats (1974)
    Springer
    Cell & tissue research 147 (1974), S. 505-527 
    Details
    ISSN: 1432-0878
    Keywords: Cartilage ; Ageing ; Chondrocyte and matrix ; Light microscopy ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, histochemical, and ultrastructural investigations have been carried out on ageing costal and tracheal cartilage of rats. The following age groups of animals have been studied: 1, 7, 14, 20, 30, 45, 75 days, 6 months, and 2 years. Ageing induces cellular changes which are represented by a reduction in the number of chondrocytes, a progressive increase in glycogen deposition, and processes of degeneration, the most frequent of which is the accumulation of lipidic material within large cytoplasmic vacuoles. Changes in the intercellular matrix become evident after 20 days in costal cartilage and after 30 days in tracheal cartilage. Chondroitin sulphate decreases while keratan sulphate, whose presence is limited to the territorial matrix, increases. Glycoproteins increase slightly in young animals and then remain constant; they decrease in the subperichondrial areas in old animals. Ultrastructurally, the matrix of cartilage of young animals contains thin collagen fibrils, most of which have no periodic banding. Roundish electron dense granules are associated with these fibrils. Irregular filaments associated with small electron-dense circular bodies are present around chondrocytes as well as within cytoplasmic vacuoles. With increasing age, and coincident with the reduction of chondroitin sulphate, the thickness of collagen fibrils increases, their period becomes evident, and the associated matrix granules decrease in number and size. Areas containing these fibrils undergo calcification, which frequently starts within roundish bodies of cellular origin. Collagen fibrils with a period of 640 Å but a highly variable thickness are often present in cartilage of adult and old rats. These fibrils seem to be due to an abnormal synthetic activity of chondrocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307252
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  • 162
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    A quantitative morphological analysis of macrophage stimulation (1974)
    Springer
    Cell & tissue research 147 (1974), S. 567-588 
    Details
    ISSN: 1432-0878
    Keywords: Macrophage ; Freund's adjuvants ; Stimulation ; Stereology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The principles of stereology have been applied to a stereometric analysis of the ultrastructural composition of normal rat peritoneal macrophages and of cells stimulated five days previously by a single intraperitoneal dose of Freund's adjuvants. Material obtained by a systematic random sampling regime was analysed and the data groups for various morphological parameters were compared. Estimates were made of cell numbers. From electron micrographs the volume proportions of nuclei, mitochondria, heterogeneous granules and rough endoplasmic reticulum were determined. The average numbers and dimensions of mitochondria, granules and free ribosomes were also evaluated. The volume-to-surface ratios of cells and their nuclei were computed. By the independent measurement of cellular volumes it was possible to obtain estimates of nuclear and cytoplasmic volumes, to evaluate the membrane surface areas of the average cells and their nuclei, and to calculate numbers of organelles per average cell. The structural alterations induced by the complete adjuvant were similar to those evoked by the incomplete adjuvant. Stimulation was characterized by a cellular hypertrophy accompanied by an increase in mean granule size and in the number of mitochondria per average cell. At the same time, there was a substantial decrease in the number of granules and a considerable depletion of both nuclear and plasma membrane surface areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307256
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  • 163
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    Electron microscope studies on the intestine using ruthenium red (1974)
    Springer
    Cell & tissue research 147 (1974), S. 271-283 
    Details
    ISSN: 1432-0878
    Keywords: Intestinum ; Diseases of the colon ; Laboratory animals ; Ruthenium red ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Ruthenium-Rot gefärbte Darmpräparate verschiedener Krankheitsbilder sowie verschiedener Laboratoriumstiere wurden elektronenmikroskopisch untersucht. Ruthenium-Rot läßt sich im Bereich des Intestinaltraktes teils homogen, teils grob- und feingranulär nachweisen. Microvilli and Glycokalyx sind relativ konstant Ruthenium-Rot gefärbt. Der Intercellularraum der Lamina epithelialis mucosae zeigt eine auffallend variable Ruthenium-Rot Anfärbung. Diese ist offenbar nicht methodisch bedingt, sondern Ausdruck eines unterschiedlichen bzw. variablen Funktionszustandes. Es bleibt offen, ob Ruthenium-Rot im Sinne einer histochemischen Reaktion bestimmte, im interzellulären Raum gelegene Substanzen markiert, oder als Tracer für den Stofftransport angesehen werden muß. Becherzellen und nekrobiotische Zellen weisen in der Regel eine konstante Ruthenium-Rot Anfärbung auf. Im Stratum proprium mucosae ist der Reaktionsausfall für Ruthenium-Rot sehr inkonstant, möglicherweise auf Grund des langen Penetrationsweges. Ziemlich regelmäßig findet sich allerdings eine Ruthenium-Rot Markierung de Phagolysosomen von Makrophagen. Prinzipielle Unterschiede der explorierten Gewebe und Tierarten bezüglich der Affinität zu Ruthenium-Rot bestehen nicht.
    Notes: Summary Biopsy specimens of human intestines in various disease states and from laboratory animal intestines have been stained with ruthenium red and inspected by electron microscopy. Ruthenium red reaction product is found as a homogeneous deposit and also in the form of coarse and fine granules. Microvilli and the glycocalyx are stained relatively constant by ruthenium red. The intercellular space of the epithelium shows a strikingly variable ruthenium red staining. This variation is apparently not related to the method but indicates differences or variations in the functional state of the membranes. It remains an open question whether the ruthenium red reaction is a histochemical reaction, marking certain substances present in in the intercellular area or whether it should be considered as a tracer for the transport of materials. Goblet cells and necrobiotic cells usually show a constant ruthenium red staining. In the lamina propria the reaction product is very inconstant, possibly on account of the long penetration path from the lumen. The phagolysosomes of macrophages are marked by ruthenium red rather regularly. No fundamental, but only quantitative differences have been found between the various kinds of tissue studied.
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    URL: http://dx.doi.org/10.1007/BF00582801
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  • 164
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    The surface film on the mesothelium of the serous membranes of the rat (1974)
    Springer
    Cell & tissue research 147 (1974), S. 595-597 
    Details
    ISSN: 1432-0878
    Keywords: Mesothelium (rat) ; Surface film ; Ruthenium red ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A surface film with a thickness of 280–570 Å covers the mesothelium of serous membranes in the rat. This film can be stained with ruthenium red. Its considerable water-binding capacity produces the reflecting surface of the serous membranes. The friction of the organs is thereby greatly reduced. Only a small amount of serous fluid must be produced to keep the surface moist. The glucosamino glycans of the surface film are probably synthesized by the mesothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307258
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  • 165
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    Ultrastructure of the photoreceptor of the planarian Dugesia dorotocephala (1974)
    Springer
    Cell & tissue research 148 (1974), S. 143-158 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptor ; Planaria ; Neurotubules ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The photoreceptors of the planarian Dugesia dorotocephala were studied by light microscopy and electron microscopy. The eye was found to be rhabdomeric; it is composed of approximately 25 visual cells and a monolayered cup of pigment cells enclosing the light sensitive rhabdome. The pigment cell gave the appearance of having a phagocytic function in addition to regulating the light entering the rhabdome. Extensions of these pigment cells were shown to be the “membranous structure” seen by light microscopy in the open area of the eye. The bipolar visual cell consisted of a perikaryon, axon and a dendritic extension comprised of a stalk, conical body and microvillous rhabdomere. Efferent nerve fibers formed synapses with dendritic spines protruding from receptor stalks. A specialized structure at the transition area between neurotubules and neurofilaments was observed in the conical body. A dense intercellular space occurred between all regions of adjoining visual cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224579
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  • 166
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    Fine structure of the spermatozoon of the sea cucumber, Leptosynapta clarki (Echinodermata: Holothuroidea) (1974)
    Springer
    Cell & tissue research 149 (1974), S. 223-233 
    Details
    ISSN: 1432-0878
    Keywords: Spermatozoon ; Holothuroidea (Leptosynapta clarki) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The spermatozoon of the holothurian Leptosynapta clarki has a small circular head measuring about 3.0 μ at the greatest diameter, a midpiece containing a single mitochondrion and a tail flagellum measuring between 35 μ and 45 μ in length. The acrosomal region contains a granule measuring 0.7 μ in diameter which consists of electron dense material arranged in concentric lamellae. Five concentric very electron dense lamellae alternate with areas of much less electron dense material in the central region of the granule. This granule rests in an anterior nuclear depression. The nucleus is circular in shape and contains one or two unbound vacuoles which frequently contain a fine granular material. Posteriorly the nucleus is bounded by a large mitochondrion and an occasional Golgi complex. The proximal centriole which contains a lateral arm of dense material lies in a deep fossa projecting into the nucleus. The distal centriole lies posteriorly in the mitochondrial mass and gives rise to nine satellite projections and their Y-shaped connective extensions. The tail contains the 9 + 2 tubule arrangement and tapers at its distal end.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222275
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  • 167
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    Ovulation and the mechanism of follicle rupture (1974)
    Springer
    Cell & tissue research 149 (1974), S. 313-327 
    Details
    ISSN: 1432-0878
    Keywords: Follicle rupture ; Rabbit ; Ovary surface epithelium ; Induced ovulation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To elucidate the intra-ovarian mechanism of follicle rupture, young, sexually mature rabbits were oophorectomized at accurately determined times after an ovulatory dose of human chorionic gonadotrophin (HCG), and the surface epithelium of Graafian follicles was studied by transmission electron microscopy. At 4 hr after injection of HCG the surface epithelial cells are considerably larger than earlier and many of them show large, round, dense, cytoplasmic bodies, particularly in the apical region of the preovulatory follicles. Up to 8 hr after injection of HCG there is a gradual accumulation of the large, dense bodies; from then on they markedly decrease in amount. Recently reported values of prostaglandins in rabbit Graafian follicles at various times after ovulatory stimulation and of steroid hormone levels in the Graafian follicle and the ovarian vein have been correlated with the ultrastructural changes. Both sex steroids and prostaglandins can labilize lysosomal membranes (and presumably other membranes as well) and may thus cause leakage of lytic enzymes. The large dense bodies of the apical surface epithelium of preovulatory follicles may represent an important source of (lysosomal) enzymes to effect weakening of the follicle wall and rupture of the follicle apex in a fairly constant area, the stigma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226766
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  • 168
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    An ultrastructural study of the spermatids of Campodea C. remyi Denis (Diplura Campodeidea) at the bundle stage (1974)
    Springer
    Cell & tissue research 149 (1974), S. 555-566 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogenesis ; Spermatid ; Campodea (apterygota) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé A un certain stade de leur évolution, les spermatides de Campodea C. remyi Denis sont réunies en petites touffes de 236 á 650 éléments. Leurs acrosomes sont implantés dans une substance homogéne (ciment) assez dense aux électrons. La spermatide comprend une région acrosomienne et une région postacrosomienne où sont alignés parallèlement: l'axonème, les deux dérivés mitochondriaux et le noyau. L'acrosome est assez long, il est renforcé par 7 à 10 microtubules. L'axonème est du type 9+9+2; les mitochondries sont de longueur presque égale. Le noyau plus court, montre une chromatine très dense aux électrons. Au niveau de la région postérieure du noyau, la membrane cytoplasmique se replie sur elle-même pour former une sorte de collerette ouverte vers l'arrière. En région distale de la spermatide, on observe au niveau d'un élargissement, une superposition de structures lamellaires.
    Notes: Summary The spermatids of Campodea C. remyi Denis are clumped in small bundles of 236 to 650 elements during spermiogenesis, their acrosomes being embedded within an homogeneous electron dense material. The spermatid comprises an acrosomal region and a postacrosomal region within which, the two mitochondrial derivatives and the nucleus are arranged in parallel. The acrosome is rather long, it is reinforced by seven to ten microtubules. The axoneme is of the 9+9+ pattern. The mitochondria are of almost equal length. The shorter nucleus shows a very electron dense chromatin. At mid-nuclear level the cytoplasmic membrane is folded up to form a sort of collar opening backwards. Distal to the nucleus, superimposed lamellar structures are found located in an expanded part of the spermatid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223032
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  • 169
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    Structure and ultrastructure of the central nervous system of the polychaete Nephtys, with special reference to photoreceptor elements (1974)
    Springer
    Cell & tissue research 149 (1974), S. 567-576 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Nervous system ; Polychaete ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Organs of presumed photoreceptor significance in Nephtys exhibit great simplicity. The pigmented eyes of Nephtys are embedded in the posterior region of the brain. Each consists of a pigment cup and two closely-associated sensory cells. The cells exhibit the characteristic features of rhabdomeric-type photoreceptor structures. The anterior or accessory eyes are identical to the pigmented eyes except that each may consist of only a single cell and that pigment cups are absent. A pair of “sensor sacs” is also present, embedded in the brain. Each consists of a single cell which has the appearance of possessing a large intracellular vesicle (the phaosome) into which project irregularly arranged microvilli. The limiting membrane is, in fact, continuous with the cell membrane. Evidence is presented of the secretion of material of unknown character into the vesicle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223033
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  • 170
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    Pycnogonid sperm. An example of inter- and intraspecific axonemal variation (1974)
    Springer
    Cell & tissue research 149 (1974), S. 105-111 
    Details
    ISSN: 1432-0878
    Keywords: Sperm flagella ; Motility ; Axonemal variation ; Axonemal evolution ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The flagella of the motile sperm cells of Nymphon leptocheles and N. rubrum (Pyonogonida, Arthropoda) exhibit a 12+0 and a 9+0 axoneme pattern, respectively. Central tubules, central sheath, spokes and arms are absent. The doublets are connected by a circular nexus. The functional significance of this axonemal composition is discussed. Aberrant axonemes occurring in high frequencies both within the species and within single specimens are probably explained by the loose axonemal connection, due to the absence of a central complex. This absence is further suggested to have facilitated the evolution from the 9+0 type to the 12+0 type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209053
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  • 171
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    The fine structure of adrenal zona glomerulosa in the adult rat (1974)
    Springer
    Cell & tissue research 149 (1974), S. 235-243 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal zona glomerulosa ; Rat ; Normal ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This paper reports on an electron microscopic study of the adrenal zona glomerulosa in the normal rat, with special emphasis on the structural diversity of mitochondria in its parenchymatous cells. The mitochondria of cristae may be tubulo-vesicular, plate-like and/or straight tubular, any one mitochondrion containing one or more types of cristae. The mitochondrial features of the zona glomerulosa parenchymatous cells are attributed to the biochemical stages of aldosterone synthesis, taking place in different mitochondria of these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222276
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  • 172
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    Intracisternal inclusions in nerve cells of cat ventromedial hypothalamic nucleus (1974)
    Springer
    Cell & tissue research 149 (1974), S. 283-286 
    Details
    ISSN: 1432-0878
    Keywords: Intracisternal inclusions ; Nerve cells ; Ventromedial hypothalamic nucleus (Cat) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar inclusions occur within cisternae of the granular endoplasmic reticulum of some perikarya of the ventromedial hypothalamic nucleus in cats. These inclusions appear as rods or bullet-shaped structures and their interiors are generally less dense. The inclusions may represent virus particles or proteinaceous products of the granular endoplasmic reticulum in which protein-synthetizing activities are probably increased to enormous extents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222280
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  • 173
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    Electron microscopy of neurosecretory nerve fibres in the neural lobe of the embryonic mouse (1974)
    Springer
    Cell & tissue research 149 (1974), S. 333-347 
    Details
    ISSN: 1432-0878
    Keywords: Neural lobe ; Mouse ; Growth and development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerve fibres of the neurosecretory hypothalamo-hypophyseal tract were studied in embryonic C3H mouse neural lobes; at least four glands at each gestational day 15–19 were examined. Single axons and small bundles of fibres are visible at gestational days 15 and 16. By day 17 large fibre bundles penetrate between glial cells. They increase in number during the next two days. Electron-lucent and electron-dense vesicles are seen in the fibres of the 15th and 16th gestational days. In the 17–19 day-old embryos development is characterized by a successive rise in the number of the two types of vesicles. The mean diameter of the electron-lucent vesicles is approximately unchanged in all the stages examined (50 nm). The electron-dense vesicles increase in size from approximately 80–90 nm at days 15–16 to 140 nm at the 19th gestational day. By day 19 contacts between neurosecretory fibre terminals and the outer basement membrane of internal and peripheral capillaries are occasionally observed. The possibly adrenergic nature of a few terminals contacting peripheral vascular structures in 17 and 18 day-old embryos is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226768
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  • 174
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    A quantitative study of the ultrastructural changes in the hypothalamo-neurohypophysial system during and after experimentally induced hypersecretion (1974)
    Springer
    Cell & tissue research 149 (1974), S. 525-535 
    Details
    ISSN: 1432-0878
    Keywords: Supraoptic and paraventricular nuclei ; Ultrastructure ; Osmotic stimulus ; Quantitative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Substitution of a 2% solution of sodium chloride in place of drinking water for 3 days significantly increased both the size of neurosecretory neurones in the supraoptic and paraventricular nuclei of rats and the proportion of these cells which had dilated endoplasmic reticulum. There was an increase in the number of multivesicular bodies per mean cell profile and also an increase in the ratio of “dense” (immature) to “pale” (mature) neurosecretory granules within the perikarya, although the total numbers of granules were unchanged. If, after 3 days of saline-treatment, the rats were again allowed tap water to drink for 2 days, the proportion of cells showing dilated endoplasmic reticulum and the number of multivesicular bodies returned towards normal, but there was a significant increase in the number of large dense lysosomal bodies per cell profile and a relative increase in the proportion of “pale” (mature) neurosecretory granules. These changes suggest that the increased bio-synthetic activity resulting from saline-treatment subsides when the treatment is terminated. Furthermore, since neurohypophysial hormone stores have still not returned to normal in animals of the recovery group, they also imply the absence of an internal feedback system by which the level of neural lobe hormone stores might govern the synthetic activity of the neurosecretory cells. Both the increased synthesis, and the increased electrical activity which accompanies it, may be independent consequences of the depleting stimulus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223030
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  • 175
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    Lipidosis-like alterations in hypothalamic neurosecretory cells of rats treated with chlorphentermine or iprindole (1974)
    Springer
    Cell & tissue research 149 (1974), S. 587-590 
    Details
    ISSN: 1432-0878
    Keywords: Chlorphentermine ; Iprindole ; Nucl.supraopticus ; Nucl.paraventricularis ; Lipidosis, drug-induced ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prolonged administration of the anorectic drug chlorphentermine or of the antidepressant agent iprindole to rats caused the formation of lamellated and crystalloid inclusions in neurosecretory cells of supraoptic and paraventricular nuclei of the rat hypothalamus The observations are interpreted as supporting the concept of a generalized phospholipidosis inducible by compounds of amphiphilic character.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223035
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  • 176
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    Morphology and ultrastructure of the antenna of male Periplaneta americana as related to chemoreception (1974)
    Springer
    Cell & tissue research 150 (1974), S. 1-9 
    Details
    ISSN: 1432-0878
    Keywords: Sensory receptors ; Insects ; Chemoreceptors ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary On the antenna of adult male Periplaneta americana, three size ranges of classical sensilla basiconica were found. Based on SEM, a sensillum of the s. trichodeum shape was revealed, but our TEM efforts indicate that this sensillum has the thin-wall, porous ultrastructure of a sensillum basiconicum. Sensilla basiconica contain flask-shaped cuticular pores. All viewed pores join four or five tubules. The pore tubules clearly contact plasma membranes of dendritic branches. Two sizes of grooved pegs were observed. The terminal segment of the antenna contains a variety of other “receptors”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220376
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  • 177
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    Investigations on the fine structure of purkinje fibres in the atrium of the avian heart (1974)
    Springer
    Cell & tissue research 150 (1974), S. 43-56 
    Details
    ISSN: 1432-0878
    Keywords: Purkinje fibres ; Avian heart ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The subendocardial Purkinje fibres in the right atrium of the heart of the adult fowl were investigated by light and electron microscopy. The myofibrils often originate from the lateral cell membrane of the cells and show a spirally wound course. Their arrangement is obviously not random. In some Purkinje cells the absolute amount of myofibrils per cell is as large as in ordinary myocardial muscle cells. The sarcoplasmic reticulum is constituted by ramifying tubules. They are distributed throughout the entire Purkinje cell and contact the myofibrils, the mitochondria, and the cell membrane. At the cell membrane the sarcoplasmic reticulum forms terminal cisternae, which often possess an electron dense content. These terminal cisternae are apparently unrelated to the Z-discs of the myofibrils. The cytoplasmic organelles of the Purkinje cell are embedded in a network of ca. 100 Å thick filaments. It is assumed that these filaments are responsible for the maintenance of the arrangement of the cell organelles. Some Z-discs of the myofibrils of the Purkinje cells are up to 0.4 μm long. Axon terminals running between the Purkinje fibre and the fibrocytic envelope may lie only 150 Å from the fibrocytes. The fibrocytes are connected by tight junctions and desmosomes and contain fine filaments and microtubules. The possible implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220379
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  • 178
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    Ultrastructure of neurohemal organs (paraganglionic plates) of Trogulus nepaeformis (scopoli) (opiliones, trogulidae) and release of neurosecretory material (1974)
    Springer
    Cell & tissue research 150 (1974), S. 67-78 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Harvestman ; Exocytosis ; Release ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les plaques paraganglionnaires de l'Opilion Trogulus nepaeformis sont des organes neurohémaux constitués d'une lamelle neurale externe, épaisse, en contact avec un sinus sanguin, d'une couche basale de cellules gliales, et de 7 types de terminaisons axonales (A1, A2, B1, B2, B3, B4 and C) renfermant des granules élémentaires qui diffèrent par leur taille, leur densité aux électrons et l'aspect de leur contenu. Les granules de type A1 se déchargent par exocytose dans l'espace extra-axonal, sous la lamelle neurale; ceux de type C se fragmentent en microgranules à contenu dense qui s'accumulent avec des vésicules claires contre l'axolemme en des places suggérant des sites de libération dans l'hémolymphe.
    Notes: Summary The paraganglionic plates of the harvestman, Trogulus, are neurohemal organs composed of a thick neural lamella facing a blood sinus, basal glial cells, and seven distinct types of axon terminals (A1, A2, B1, B2, B3, B4 and C) identified on the basis of elementary granule size, electron density, and structure of contents. The release of A1 type granules occurs by exocytosis into the extraaxonal space below the acellular neural lamella. The release of the content of C granules occurs after fragmentation into small electron dense vesicles. Clusters of these vesicles intermixed with clear vesicles pressing against the axolemma beneath the neural lamella, apparantly correspond to the sites of release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220381
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  • 179
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    The ultrastructure of binucleate keratinocytes and binucleation in palatal mucosa of guinea pigs (1974)
    Springer
    Cell & tissue research 150 (1974), S. 113-123 
    Details
    ISSN: 1432-0878
    Keywords: Binucleation ; Amitotic nuclear division ; Palatal epithelium (Guinea pig) ; Keratinocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The palatal epithelium of adult male guinea pigs contains a considerable number of binucleate epithelial cells in all strata but the basal cell layer. Electron microscopical examination shows that the two equal-sized nuclei are dome-shaped with the flattened surfaces closely approximated, the distance between the nuclei being 30 nm or more. No points of contact have been found between the nuclear membranes. No differences in number, distribution or ultrastructure of cytoplasmic organelles were found between mono- and binucleate epithelial cells. Evidence of amitotic nuclear division being a plausible mechanism of binucleation is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220385
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  • 180
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    The distribution of noradrenergic nerves and small, intensely fluorescent (SIF) cells in the cat urinary bladder (1974)
    Springer
    Cell & tissue research 150 (1974), S. 147-159 
    Details
    ISSN: 1432-0878
    Keywords: Urinary bladder ; Autonomic innervation ; SIF cells ; Fluorescence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fluorescence and electron microscopy have been used to study the distribution of noradrenergic nerves in the smooth muscle of the cat urinary bladder. Using the former technique, relatively few fluorescent noradrenergic nerves were observed in the body and fundus, while a rich plexus occurred adjacent to muscle cells of the bladder neck. The trigone could not be distinguished neuromorphologically from detrusor muscle in this region. Electron microscopy showed that the majority of noradrenergic terminals in the body and fundus were associated with presumptive cholinergic axons, while in the bladder neck noradrenergic terminals formed typical neuroeffector relationships with individual smooth muscle cells. Numerous ganglia occurred both in the adventitia and among the smooth muscle bundles, particularly in the bladder neck. The majority of the nerve cell bodies were non-fluorescent, although many contained bright orange autofluorescent granules, believed to be lysosomes. A small minority of ganglion cells were associated with fluorescent noradrenergic nerve terminals, thereby providing structural evidence for limited intraganglionic inhibition. In addition, occasional groups of small intensely fluorescent (SIF) cells were observed in some intramural ganglia and these were subsequently identified in the electron microscope. The possibility that these cells may provide a second inhibitory influence on bladder activity was considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222166
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  • 181
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    An ultrastructural analysis of early fertilization in the sand dollar, Echinarachnius parma (1974)
    Springer
    Cell & tissue research 150 (1974), S. 343-368 
    Details
    ISSN: 1432-0878
    Keywords: Fertilization ; Gametes ; Echinoid ; Echinarachnius ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of gametes of a representative echinoid, Echinarachnius parma were investigated ultrastructurally with particular emphasis on gamete interaction during fertilization. The acrosomal region of the spermatozoon is characterized by the presence of two components: an acrosomal vesicle and periacrosomal materials. The acrosomal vesicle, which is completely bounded by a limiting membrane, is surrounded by periacrosomal materials. Nuclear and mitochondrial regions of the spermatozoon are also described briefly. The ovum is surrounded by two extraneous coats: an outer jelly layer and an inner vitelline envelope. Pigment cells are present within the outer jelly layer. Ooplasmic organelles and inclusions including cortical granules and the female pronucleus are described. Spermatozoa undergo the acrosomal reaction in the vicinity of mature ova. Events of acrosomal reaction, including dehiscence of the acrosomal vesicle and acrosomal tubule formation, are described and summarized schematically. Acrosomal vesicle contents remain adherent to the outer surface of the tubule membrane. Primary binding of the spermatozoon to the surface of the ovum is accomplished by the establishment of morphological continuity between this extracellular coat and the vitelline envelope of the ovum. It is suggested that the species specificity of fertilization resides in this primary binding of gametes. Membrane fusion, between the tip of the acrosomal tubule and the colemma, follows primary binding and cytoplasmic continuity of the gametes is thereby established. It is concluded that the early events of fertilization in Echinarachnius parma generally conform to the Hydroides-Saccoglossus pattern of the Colwins (1967).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220142
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  • 182
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    The sarcolemma of skeletal muscle fibres as demonstrated by a replica technique (1974)
    Springer
    Cell & tissue research 150 (1974), S. 377-387 
    Details
    ISSN: 1432-0878
    Keywords: Sarcolemma ; Collagen texture ; Frog ; Electron microscopy ; Replica technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Single stage carbon replicas were obtained from dried bundles of frog skeletal muscle fibres at different sarcomere lengths. In unfixed specimens finer details are masked by an amorphous substance; after fixation with glutaraldehyde a network of collagen fibrils covering the muscle fibres appears. At a sarcomere length of 1.8 μm the collagen fibrils are oriented diagonally and transversely; between a sarcomere length of 2.8 and 3.1 μm the collagen fibrils are increasingly oriented along the axis of the muscle fibre. This indicates a helical arrangement of the collagen fibrils in the sarcolemma, the pitch being grossly related to sarcomere length. Collagen fibrils and fibres in the endomysium are not oriented according to sarcomere length; hence at low degrees of stretch, force applied to the tendon is primarily transmitted by the muscle fibres and not by the endomysium. Replicas from skinned fibres showed that shrinkage is most pronounced in the I-bands and least in the Z-and M-lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220144
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  • 183
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    The acrosome reaction in the sperm of the shipworm Bankia australis calman (Bivalvia, Mollusca) (1974)
    Springer
    Cell & tissue research 151 (1974), S. 93-101 
    Details
    ISSN: 1432-0878
    Keywords: Acrosome reaction ; Bankia australis ; Teredo ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the acrosome reaction in the sperm of the teredo, Bankia australis, is described. In brief, the reaction consists of three phases: (a) formation of a bleb and membrane fusion, (b) disappearance of the longitudinally oriented fibrils, and (c) outward flaring and disappearance of the osmiophilic granule. The osmiophilic granule appears to consist of prism-like structures. The axial rod never lengthens during the acrosome reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222037
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  • 184
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    Similarities between Hassall's corpuscles of the human thymus and the epidermis (1974)
    Springer
    Cell & tissue research 151 (1974), S. 347-368 
    Details
    ISSN: 1432-0878
    Keywords: Human thymus ; Hassall's corpuscles ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Substrate-histochemical, enzyme-hystochemical and ultrastructural investigations were performed on thymic tissue from children, obtained in heart operations. β-Amylaseresistant, PAS-positive and Hale-positive substrates presumably neutral and acid mucosubstances, can be demonstrated in the central concentric lamellae of Hassall's corpuscles (HC). These lamellae also give positive reactions for sulphydryl groups and disulphide groups. Some flattened cell elements gave strong reactions for phospholipids, and small sudanophilic droplets, presumably neutral fats, are scattered throughout the HC. All investigated hydrolases and dehydrogenases either give no or only very weak reactions in the central part of progressive HC, but react strongly positive in their peripheral hypertrophic epithelial cells. In the central part of regressive HC, positive reactions for acid phosphatase and β-D-glucuronidase were recognized. These lysosomal enzymes may indicate degenerative processes. By electron microscopy progressive HC show central concentric lamellae with an amorphous matrix tightly filled with tonofilaments. They are surrounded by a thickened plasma membrane (200 Å), and do not contain nuclei. These central lamellae resemble the horny cells of the epidermis. The peripheral hypertrophic epithelial cells have pale nuclei with one or two nucleoli. Their cytoplasm contains numerous tonofibrils. These cells resemble stratum spinosum cells of the epidermis. In regressive HC the central concentric lamellae loose their intercellular contacts. The widened intercellular spaces are filled with cellular debris, and are invaded by macrophages. Similarities between the ultrastructure and the patterns of the histochemically investigated substrates and enzymes in human HC and epidermis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224546
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  • 185
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    The organization of the sarcoplasmic reticulum in teleost ventricular myocardial cells (1974)
    Springer
    Cell & tissue research 151 (1974), S. 395-402 
    Details
    ISSN: 1432-0878
    Keywords: Heart ; Teleost ; Sarcoplasmic reticulum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the sarcoplasmic reticulum in myocardial cells of the ventricle of the trout heart is described as the result of an investigation with the electron microscope. The sarcoplasmic reticulum is sparse in distribution compared to that of birds or mammals but shows a fundamentally similar organization. A very loose network of fine tubules is in intimate contact with the myofibrils but with no local modification with respect to the arrangement of myofilaments within the sarcomeres. There is no special association of the sarcoplasmic reticulum with the Z-bands. Some tubules pass to the cell periphery where they expand to form subsarcolemmal cisternae in which electron-dense matter is often seen. The occurrence of the subsarcolemmal cisternae (peripheral couplings) is random and they are not observed in the vicinity of intercalated discs. The sarcoplasmic reticulum is discussed in relation to excitation-contraction coupling in teleost myocardial cells, and in comparison with that of other vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224549
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  • 186
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    Studies on the juxtaglomerular apparatus (1974)
    Springer
    Cell & tissue research 151 (1974), S. 471-480 
    Details
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Rat ; Influence of deoxycorticosterone (DOC) ; Electron microscopy ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die quantitativ-morphologische Analyse des juxtaglomerulären Apparates nach DOC-Behandlung zeigte, daß mit der Hemmung der Reninbildung eine Hypoplasie der epitheloiden Zellen des juxtaglomerulären Apparates einhergeht. Der Granulagehalt der juxtaglomerulären Zellen nahm ab; die Kern-Plasma-Relation änderte sich und die Leiomyofibrillen in den Epitheloidzellen nahmen zu. An den übrigen Anteilen des juxtaglomerulären Apparates, insbesondere der Macula densa, wurden keine morphologischen Veränderungen beobachtet. Die DOC-Behandlung führte darüber hinaus zu einer Bildung von Einschlüssen in den Podocyten, den Mesangiumzellen und den Zellen der Bowman-Membran. Die verschiedenen Möglichkeiten, über welche Faktoren die juxtaglomerulären Zellen nach DOC-Behandlung degranuliert werden, werden diskutiert. Das ultrastrukturelle Bild der Epitheloidzellen nach DOC-Behandlung entspricht deutlich einer gehemmten Sekretion, da das Ergastoplasma und der Golgi-Apparat ganz besonders stark zurückgebildet werden.
    Notes: Summary Quantitative morphological analysis of the Juxtaglomerular apparatus of rats treated with deoxycorticosterone (DOC) and salt revealed hypoplasia of the epithelioid cells as a concomitant of the inhibition of renin synthesis. The granular content of the Juxtaglomerular cells was significantly decreased, while the nucleus-to-cytoplasm ratio and the volume density of leiomyofilaments in the epithelioid cells increased. No morphological alterations were observed in the remaining constituents of the Juxtaglomerular apparatus, including the macula densa. DOC-treatment also induced the appearance of inclusions in the podocytes in the cells of the mesangium, and in the cells of Bowman's capsule. The possible mechanisms of degranulation of the Juxtaglomerular cells after treatment with DOC are discussed. The ultrastructural appearance of the epithelioid cells after treatment with DOC corresponds to an inhibition of secretion, since the rough endoplasmic reticulum and the Golgi apparatus undergo marked regressive changes.
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    URL: http://dx.doi.org/10.1007/BF00222992
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  • 187
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    The reaggregation of neurons and their satellite cells in cultures of trypsin-dissociated spinal ganglia (1974)
    Springer
    Cell & tissue research 152 (1974), S. 175-183 
    Details
    ISSN: 1432-0878
    Keywords: Cell aggregation ; Spinal ganglia ; Cell cultures ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dorsal root spinal ganglia of chick embryos were trypsinized and the cellular components isolated. Suspensions of these cells reaggregate. During this process satellite glial cells and neurons established intimate contacts. The reconstructed glial envelopes around the neurons are morphologically similar to the ones formed in the intact animal during development. The formation of the characteristic glial-neuronal relation is an example of specific cell recognition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224693
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  • 188
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    The interaction of phagocytes and the large-sized parasite Cryptococcus neoformans: Cytochemical and ultrastructural study (1974)
    Springer
    Cell & tissue research 152 (1974), S. 165-174 
    Details
    ISSN: 1432-0878
    Keywords: Phagocytosis ; Large foreign bodies ; Cryptococcus neoformans ; Tissue culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The yeast Cryptococcus neoformans may develop under certain conditions a large polysaccharide capsule 50–100 μM in diameter and therefore cannot be phagocytosed by either polymorphonuclear cells (PMN's) or mononuclear phagocytes (MN's). The cellular defense mechanism — in various animals — against the yeast is composed by formation of ringlike structure of PMN's or MN's cells which surround the C. neoformans. Ring structures develop either in vivo or in vitro in tissue culture; destruction of the yeast occurs within 36–72 hours. Several hydrolases, such as acid phosphatase, β-glucuronidase and non-specific esterase were found to be released from the phagocytic cells into the enclosed yeast. Considerable reduction of NBT used as a marker for oxidative activity was observed in MN rings at contact regions of the MN cells and the yeast. Electron microscopic studies indicate that the phagocytic cells in the ring structure have many pseudopodes penetrating into the polysaccharide capsule of the yeast. Disintegration of the capsule was observed as well as phagocytosis of its material. A possible analogy between normal phagocytosis of small-sized bodies and the ring structure obtained when large bodies are involved is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224692
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  • 189
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    Fine structure of the fat body of the female of Calliphora erythrocephala during the first egg-maturation cycle (1974)
    Springer
    Cell & tissue research 152 (1974), S. 193-217 
    Details
    ISSN: 1432-0878
    Keywords: Imaginal fat body ; Calliphora erythrocephala ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During the first egg-maturation period (6 days at 25° C) the adult fat body of the female of Calliphora goes through sequential changes correlated with the development of the oocytes. The first two days represent a growth and differentiation phase. Free ribosomes and rough endoplasmic reticulum (RER) gradually increase in quantity. Golgi complexes consisting of clusters of vesicles and vacuoles appear to bud off from cisternae of the RER. Dense bodies possibly arise by sequestration from Golgi complexes. Content of acid phosphatase shows the dense bodies to be lysosomes. Many contain crystalloids. Glycogen is first seen as a network, in which gamma-elements appear; later alpha-particles occur. Lipid droplets are abundant. Lipid droplets break down where they border upon glycogen. In four-day old females the fat body is in a phase of production. Golgi complexes concentrate protein secretion granules believed to represent yolk protein. Then follows a phase of regression characterized by the formation of cytosegresomes and by an accumulation of lipid. In mature females a remodeling of the fat cell begins, evidenced by a renewed formation of free ribosomes, RER, and probably dense bodies resembling those of the one-day old female.
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    URL: http://dx.doi.org/10.1007/BF00224695
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  • 190
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    Electron microscopical and cytochemical study of vitelline cells in the fresh-water triclad Dugesia lugubris s.l. (1974)
    Springer
    Cell & tissue research 152 (1974), S. 219-228 
    Details
    ISSN: 1432-0878
    Keywords: Vitelline cells ; Dugesia lugubris (Turbellaria, Tricladida) ; Yolk material ; Ultrastructure ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of vitelline cells in the fresh-water Triclad Dugesia lugubris has been studied by means of electron microscopic and cytochemical techniques. We observed a single cell type in different stages of development more or less evenly distributed from the periphery towards the centre of the follicles. Young vitelline cells have the characteristic morphology of cells in early stages of maturation: they show a large nucleus, a nucleolus with fibrillar and granular components, and many ribosomes in an undifferentiated cytoplasm. Subsequently, large amounts of parallel arrays of granular endoplasmic reticulum and some Golgi complexes appear and the vitelline cells assume the typical appearance of secretory cells. Reserve substances progressively accumulate in the vitelline cells, which when mature appear very electron dense. We have recognized the following types of reserve substances: 1) Neutral lipid droplets which are the first to appear and can reach a diameter of 4–5 μm or more. 2) Yolk globules of 2–3 μm in diameter which appear simultaneously with cocoon-shell globules but are clearly different from them in structure and chemical composition. The yolk globules probably arise from the cooperation between endoplasmic reticulum and Golgi complexes and have a very complex proteinaceous nature. 3) Large amounts of α-glycogen granules which occupy cytoplasmic sacs.
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    URL: http://dx.doi.org/10.1007/BF00224696
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  • 191
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    Involution of the caudal musculature during metamorphosis in the ascidian, Botryllus schlosseri (1974)
    Springer
    Cell & tissue research 153 (1974), S. 293-305 
    Details
    ISSN: 1432-0878
    Keywords: Ascidia (Botryllus schlosseri) ; Metamorphosis ; Muscle tissue involution ; Phagocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The caudal musculature of the free-swimming tadpole of the ascidian, B. schlosseri consists of cylindrical mononucleated cells connected in longitudinal rows flanking the axial notochord. During resorption of the larval tail, which is apparently induced by the contraction of the epidermis, muscle cells are dissociated and pushed into the body cavity where most of them are rapidly engulfed by phagocytes. In the initial stages of tail withdrawal muscle cells display surface alterations due to the disruption of intercellular junctions and disarrangement of myofibrils. Extensive degenerative changes, with shrinkage of mitochondria and disintegration of the contractile material are subsequently observed. Lysosomes and autophagic vacuoles are rarely seen and appear to play a secondary role in the degradation of the muscle cells, which occurs predominantly within the phagocytes. Myofilaments and myofibrils have never been observed within autophagic vacuoles. Clumps of muscle fragments and degenerated phagocytes undergo eventual dissolution in the blood lacunae, concomitantly with the differentiation of the young oozooid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229160
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  • 192
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    Adhesion plaques associated with the production of a daughter cell in Euglypha (Testacea; Potozoa) (1974)
    Springer
    Cell & tissue research 153 (1974), S. 261-268 
    Details
    ISSN: 1432-0878
    Keywords: Amoebae (Testacea) ; Siliceous plates ; Production ; Role of microtubules in fission ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Euglypha acanthophora and Euglypha strigosa, testate amoebae with siliceous shells, undergo binary fission producing daughter cells. The siliceous plates from which the shells are constructed are produced in the Golgi and perinuclear regions of the parent. At binary fission these pass along microtubule pathways and are manoeuvered into position in the daughter-cell by microtubule (20–25 nm) and microfilament (7–9 nm) systems. The latter in the form of adhesion plaques are instrumental in the coordination and deployment of the shell-plates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226614
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  • 193
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    Electronic Resource
    Transformations of hypothalamic arcuate neurons (1974)
    Springer
    Cell & tissue research 153 (1974), S. 497-515 
    Details
    ISSN: 1432-0878
    Keywords: Arcuate nucleus ; Hypothalamus ; Sexual cycle ; Ribbon-rolls ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in subcellular structures of arcuate neurons correlated in a consistent way with stages of the estrous cycle of the rat. Associated with the rough endoplasmic reticulum short ribbons of moderately electron dense material appeared at metestrus and circular or elliptical bodies termed “ribbon-rolls” at diestrus and proestrus. Although present in proestrus, the ribbon-rolls were smaller at this stage. In a few neurons in diestrous females and in ovariectomized animals one to seven months before perfusion multiple large ribbon-rolls occupied much of the cytoplasm. Also, frequency of dense granules and lysosomes increased in diestrus. The significance of the ribbon-rolls and changes in other structures during the estrous cycle are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231543
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  • 194
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    Electronic Resource
    The ultrastructure of the medial preoptic area of the rat (1974)
    Springer
    Cell & tissue research 153 (1974), S. 517-530 
    Details
    ISSN: 1432-0878
    Keywords: Medial preoptic area ; Hypothalamus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neuronal and glial cell bodies and the neuropil of the medial preoptic area of the rat hypothalamus were studied under the electron microscope. Two different types of neurons are identified on the basis of electron density. These two types differed in a number of ultrastructural features. Three types of nerve terminals based on vesicle morphology are also described, as well as the general structure of the axons, dendrites and synapses in the neuropil. The structure of oligodendrocytes and astrocytes is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231544
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  • 195
    Electronic Resource
    Electronic Resource
    The ventricular system in neuroendocrine mechanisms (1974)
    Springer
    Cell & tissue research 154 (1974), S. 1-16 
    Details
    ISSN: 1432-0878
    Keywords: Ventricle ; Tanycytes ; Monoamine transport ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This investigation has dealt with a light and electron microscopic autoradiographic analysis of the median eminence of the rat following intraventricular infusion of 3H-dopamine. This study has demonstrated that 3H-dopamine, once infused into the mammalian cerebral ventricular system, is rapidly and selectively absorbed by tanycytes and transported to the contact zone within 5 minutes after ventricular infusion. Certain axon terminals in the ependymal, hypendymal, and palisade-contact zones selectively sequester 3H-dopamine as do subpopulations of arcuate neurons. This picture of intense labelling of neurons and axon terminals is discussed with respect to monoaminergic re-uptake mechanisms. Uptake and transport of 3H-DA by tanycytes is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221067
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  • 196
    Electronic Resource
    Electronic Resource
    Fine structure of the testicular gland of the black goby, Gobius jozo L. (1974)
    Springer
    Cell & tissue research 154 (1974), S. 39-49 
    Details
    ISSN: 1432-0878
    Keywords: Gobius jozo (Teleost) ; Testis ; Steroidogenic tissue ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The homologue of mammalian Leydig cells in the testis of fish of the genus Gobius is believed to be a glandular mass lying along the mesorchium and quite distinct from the seminiferous region. This gland was studied in Gobius jozo by light and electron microscopy. Histologically, the gland is composed of cords of polyhedral cells located between the main vessels of the testis and the deferent duct. Dark and light cell varieties were observed both after staining with toluidine blue and with respect to their cytoplasmic electron density. The fine structure of the glandular cells is characterized by a well developed agranular endoplasmic reticulum in the form of random anastomosing tubules and vesicles and by very numerous mitochondria with tubulo-vesicular cristae. In some mitochondria the internal organization is paracrystalline. One or two bodies of unknown nature are Found in the Golgi region. They are partially limited by an unusually thick membrane and contain a material subdivided mostly into small vesicles. Liposomes and lipofuscin pigment granules are also present. The ultrastructural features of the glandular cells of the testis of Gobius jozo confirm a specialization in steroid hormone production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221070
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  • 197
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    Electronic Resource
    A new membrane organelle in developing amphibian neurones (1974)
    Springer
    Cell & tissue research 154 (1974), S. 103-108 
    Details
    ISSN: 1432-0878
    Keywords: Plasma membrane specialisations ; Developing neurons ; Xenopus laevis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Membrane specialisations have been found on neurones in embryos of the clawed toad Xenopus laevis. The specialisations have been called dense membrane knobs and consist of an outpushing of the plasma membrane with a slight increase in its density. The out-pushing forms a spherical knob with an amorphous dense core and a total diameter of 500 to 600 Å. The knobs are found on axons and dendrites both in the spinal cord and peripherally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221074
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  • 198
    Electronic Resource
    Electronic Resource
    Gap junctions in the heart of teleost fish (1974)
    Springer
    Cell & tissue research 154 (1974), S. 131-134 
    Details
    ISSN: 1432-0878
    Keywords: Heart musculature ; Teleost ; Gap junctions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An examination of cell contacts was made in the atrial and ventricular muscle of Teleost fish. The intercalated discs consist of two types of junction resembling fascia and macula adherens. Small focal areas of gap junctions were shown to be numerous away from the regions of intercalated disc between the myocardial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221077
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  • 199
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    Electronic Resource
    The goldfish pituitary (1974)
    Springer
    Cell & tissue research 154 (1974), S. 211-230 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Goldfish ; Cell types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the goldfish, Carassius auratus, morphological and functional aspects of the pituitary gland were studied at the ultrastructural level and six cell types could be distinguished in the pars distalis. Acidophilic cells of the rostral pars distalis were identified as prolactin cells, the chromophobic cells of the rostral pars distalis as ACTH cells, the non-globular basophilic cells of the rostral and the proximal pars distalis as TSH cells, the globular basophils of the proximal pars distalis as gonadotropic cells and the acidophils of the proximal pars distalis as somatotrophs. Besides some of the well established criteria of morphological and functional identification of different cell types, two new approaches have been used in the present study. One was to express the electron density of secretory granules objectively by means of a photometric method. It was found that both types of acidophilic cells which produce the proteohormones prolactin and somatotropin respectively, had granules with the highest electron densities. The basophilic cells producing the glycoproteins gonadotropin and TSH respectively, possessed granules of intermediate electron density whereas the chromophobic cells storing the peptide hormone ACTH had granules of lowest densities. The second new approach was the administration of the synthetic mammalian releasing hormones LH-RP and TRF, which helped in identifying gonadotropic and thyrotropic cells respectively. In the goldfish there is evidence for the presence of only one type of gonadotropic cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223165
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  • 200
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    Electronic Resource
    The ultrastructure of the skin of Tilapia mossambica (Peters) (1974)
    Springer
    Cell & tissue research 154 (1974), S. 251-264 
    Details
    ISSN: 1432-0878
    Keywords: Skin ; Tilapia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the skin of Tilapia mossambica (Peters) is described. In certain areas the epidermal surface forms so-called Epidermal Surface Patterns. Two types of epidermal cells are distinguished and their differences noted. The epidermal surface is covered by a layer of acid mucopolysaccharide, yet the contents of the mucus cells did not react with ruthenium red. The dermis consists mainly of bundles of collagen fibres and associated fibroblasts, but melanophores, iridophores and complex melano-iridophores are also present. Aspects of the development and structure of the guanine platelets and the melanosomes are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223167
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