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  • Articles  (94)
  • Ultrastructure  (94)
  • Springer  (94)
  • Nature Publishing Group
  • 1975-1979  (94)
  • 1978  (94)
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  • Articles  (94)
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  • Springer  (94)
  • Nature Publishing Group
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  • 1975-1979  (94)
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  • 1
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    Electronic Resource
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    ISSN: 1432-0827
    Keywords: Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
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  • 2
    ISSN: 1432-041X
    Keywords: Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notes: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
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  • 3
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    Development genes and evolution 185 (1978), S. 235-248 
    ISSN: 1432-041X
    Keywords: Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
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  • 4
    ISSN: 1432-0827
    Keywords: Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
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  • 5
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    Archives of microbiology 117 (1978), S. 293-295 
    ISSN: 1432-072X
    Keywords: Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
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  • 6
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    Archives of microbiology 118 (1978), S. 309-316 
    ISSN: 1432-072X
    Keywords: Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
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  • 7
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    Archives of microbiology 116 (1978), S. 279-288 
    ISSN: 1432-072X
    Keywords: Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
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  • 8
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    Cell & tissue research 186 (1978), S. 121-133 
    ISSN: 1432-0878
    Keywords: Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
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  • 9
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    Cell & tissue research 186 (1978), S. 227-240 
    ISSN: 1432-0878
    Keywords: Pancreas (rat) ; Pancreatic duct ligation ; Cell membrane ; Intercellular junctions ; Ultrastructure ; Freeze fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exocrine pancreatic tissue was investigated during various intervals after pancreatic duct ligation. Concomitant to the increase of the intraluminal pressure, alterations are found in the arrangement of the luminal membrane surface and the zonulae occludentes of the acinar cells. The zonulae occludentes exhibit a disarrangement of their strands. The number of strands diminishes and small interruptions as well as large discontinuities of the strands are observed in most regions of the acinar cells. Furthermore, gap junctions are found very infrequently between acinar cells. The ultrastructural alterations of the zonulae occludentes suggest a gradual adaptation to the increasing unilateral pressure. However, a leakage of the paracellular permeability barrier occurs which contributes to the known shunt between the compartments of the pancreatic juice and the interstitial space following pancreatic duct obstruction. The present investigation is a further example of alterations in the paracellular permeability and intercellular communication of epithelial cells under pathological conditions.
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  • 10
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    Cell & tissue research 186 (1978), S. 435-452 
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Arthropod ; Spider (Argiope amoena) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anterolateral eye, the posterolateral eye and the posteromedial eye of the web-building spider, Argiope amoena have been examined by light and electron microscopy. The dioptric apparatus of all three eyes is similar in structure, and consists of a cornea, a lens and a vitreous body. The retina contains monopolar receptor cells, the cell bodies of which are present beneath the vitreous body in all three eyes. Proximal processes of the receptor cells form rhabdoms beneath the cell body layer and then extend toward the first optic glomerulus as an ocellar nerve. Two distinct patterns of retinal organization are present in the three eyes. In one type the rhabdomic layer of the retina is backed by a pigmented layer. In the other type the rhabdomic layer is backed by a tapetal reflecting layer. Rhabdomic structure and cytoplasmic inclusions of the receptor cells differ greatly between the two types. The anterolateral eye possesses a single type of retina with the rhabdoms backed by the tapetum. Both the posterolateral and the posteromedial eye are similar in structure, each possessing beneath the common dioptric apparatus retinae of both types.
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  • 11
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    Cell & tissue research 188 (1978), S. 19-33 
    ISSN: 1432-0878
    Keywords: Subfornical organ ; Circumventricular organ ; Coturnix quail ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the subfornical organ (SFO) of the Japanese quail has been studied by light and electron microscopy. The SFO is a small semiglobular bulge in the midline on the rostrodorsal wall of the third ventricle between the anterior commissure and tela choroidea. The organ consists of three main parts, anterior stalk, the corpus and the posterior stalk. The anterior stalk is covered by ependymal cells with a few cilia, but the corpus and posterior stalk are characterized by a distinctive lack of cilia and by flat or bulging cell surfaces, which have the appearance of cobble stones. The large bulbous protrusions in the ependymal surface of the posterior stalk suggest a secretory function into the ventricle. In the subependymal layer, there are a few parvocellular neurons that contain small mitochondria, moderately developed Golgi apparatus, lysosomes, dilated cisternae of rER and a few dense-cored granules of 100–120 nm in diameter. They appear to be secretory in nature. Two types of glial cells occur in the subependymal and internal layers. One is small and spindle-shaped with a dense nucleus and elongated cytoplasmic processes; it may be microglial. The other is a small polygonal cell with rounded nucleus and clear cytoplasm containing bundles of filaments; it may be a protoplasmic astrocyte. The neuropil contains three types of axons. The first contains dense-cored granules, 80 nm in diameter, and clear vesicles, 40–60 nm in diameter and is involved in axosomatic synapses. The second type contains dense granules, 120 nm in diameter, and clear vesicles, 40–80 nm in diameter, and shows axodendritic synapses. The third contains peptidergic granules about 100–120 nm in diameter and seems to belong to the organ-specific nerve cells. These axons terminate at the perivascular space of the blood capillaries, suggesting secretion into the blood.
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  • 12
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    Cell & tissue research 189 (1978), S. 203-217 
    ISSN: 1432-0878
    Keywords: Astrocytes ; Development ; Phagocytosis ; Neuroplasticity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies have demonstrated that astrocyte processes are responsible for a spontaneously occurring phagocytosis of boutons on cat spinal motoneurons during the second postnatal week. In the present investigation, the astrocytes and the astrocyte processes in contact with the motoneurons were studied qualitatively and quantitatively during the early postnatal period. It could be concluded that the cells responsible for the phagocytosis of boutons are immature astrocytes. These cells were present not only during the period of phagocytosis but also prior to this period. The type of process responsible for the phagocytosis was present not only during the period of phagocytosis but also prior to and after that period although the relative contribution of such processes to the glia-covered membrane area of the motoneurons was reduced in the older animals. On the basis of these results, the possible specificity of the immature astrocyte as the element responsible for the phagocytosis of boutons during normal development is discussed.
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  • 13
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    Cell & tissue research 189 (1978), S. 435-440 
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Sinus gland ; Synapses ; Palaemon ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two types of neurosecretory fibers, designated as Type 5 and Type 6 axons, in the sinus gland of the freshwater prawn, Palaemon, establish contact with other neurosecretory axons by means of synaptic junctions. This finding strongly supports the view that release of some neurohormones from the eyestalk may be regulated by neurosecretory neurons through synaptic transmission.
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  • 14
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    Cell & tissue research 191 (1978), S. 449-462 
    ISSN: 1432-0878
    Keywords: Ileum (Rat) ; Occluding junctions ; Freeze-fracture ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two kinds of occluding junctions are found between ileal epithelial cells of suckling rats: apical zonulae occludentes (ZO) and fasciae occludentes (FO) which are associated with the lateral plasma membranes of many epithelial cells. In unfixed preparations, glycerol treatment induces the further proliferation of extensive fasciae occludentes. Both kinds of junction have identical structural elements when visualized in freeze fracture replicas, although the arrangement of these elements differs. Zonulae occludentes consist of networks of branching and anastomosing linear ridges or rows of ∼10 nm particles with 20–30 nm spaces between the rows which form narrow belt-like structures around the apical region of adjacent cells. Fasciae occludentes, on the other hand, consist of similar linear ridges or rows of particles but the junction strands are often discontinuous, open ended and only occasionally intersect with each other. Several different fracture planes through the plasma membrane in the region of the occluding junctions have been observed and these provide further evidence that two components, one from each membrane, fused at the level of the extracellular space, form the junction sealing element. Furthermore, we present evidence which indicates a staggered rather than an in-register arrangement of these two components.
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  • 15
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    Cell & tissue research 191 (1978), S. 501-506 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Ultrastructure ; Perivascular space ; Hormonerelease ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural lobes from rats subjected to neurohypophysial hormone-releasing stimuli were examined electron microscopically following fixation in 4 % tannic acid in 2.5 % glutaraldehyde. This fixation allowed the delineation of the perivascular space in the neural lobe tissue. Measurement of the area of the perivascular space showed that it was significantly increased in the rats subjected to vagal stimulation and intraarterial calcium ions compared to the control rats. The rats which had been subjected to haemorrhage as a hormonereleasing stimulus did not show any significant change in the area of the perivascular space. The significance of these findings in relation to hormone release is discussed.
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  • 16
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    Cell & tissue research 192 (1978), S. 1-23 
    ISSN: 1432-0878
    Keywords: Lymph node (rat) ; Macrophages ; Dendritic reticulum cells ; Immune response to paratyphoid vaccine ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The reactivity of rat lymph node macrophages and reticulum cells has been studied in relation to the course of the immune response. Special attention was paid to the interdigitating cells (IDC) in the paracortex and the dendritic reticulum cells (DRC) in the germinal centre. Different types of macrophage predominate in the three different phases of the immune response. In the induction phase exudate macrophages predominate. They transform their morphology depending on the micro-environment in which they settle. These cells may contain Birbeck granules. Our experiments suggest, that these granules are immunologically specific organelles, associated with the induction of a primary humoral response. In the proliferation phase transitional cells between newly arrived macrophages and IDC predominate in the paracortex and the number of IDC decreases. In the memory phase IDC repopulate this thymus dependent area, indicating that the characteristic morphology of these cells results from the immune response in the T cell environment. The DRC are specifically related to the germinal centre, the morphological transformation of this peculiar reticulum cell occurs under the influence of the germinal centre reaction. The germinal centre reaction originates by tingible body macrophages (TBM).
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  • 17
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    Cell & tissue research 192 (1978), S. 25-38 
    ISSN: 1432-0878
    Keywords: Esophageal epithelium ; Eel ; Seawater adaptation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The esophageal epithelium of the Japanese eel, Anguilla japonica, was studied by light and electron microscopy. In freshwater-adapted eels, longitudinal folds of the mucosal surface are simple in form and lined by a stratified epithelium composed of mucous cells, filament and ribosome-rich cells. Mucous cells are numerous. The filament-rich cells form the outermost and the basal layers of the stratified epithelium and are scattered in the middle zone among the mucous cells. They are firmly bound to one another by many desmosomes and prominent interdigitations of plasma membrane. The distal free surface of the filament-rich cell has a fingerprint-like pattern of microridges. A small number of columnar cells occur at the apices of the folds. They are rich in mitochondria and their distal surfaces bear short microvilli. In seawater-adapted eels, irregularly meandering folds increase the surface area of the mucosa. The stratified epithelium is extensively replaced by a simple columnar epithelium free of mucous cells. The columnar cells resemble in many respects those found in freshwater-adapted eels. They are rich in mitochondria and their distal free surface were provided with short microvilli. However, prominent lateral intercellular spaces and elaborate interdigitations of cytoplasmic processes in the distal zone distinguish the former from the latter. Results are considered in connection with the changes in ion and water permeability of the epithelium after seawater adaptation.
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  • 18
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    Cell & tissue research 192 (1978), S. 77-87 
    ISSN: 1432-0878
    Keywords: AV-node ; AV-bundle ; Fenestrated capillary endothelium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The capillaries in the atrioventricular node and atrioventricular bundle of the heart (mammals) were investigated by thin sections and freezeetch replicas. Fenestrated endothelial cells were found to occur in all mammals examined in this study. These fenestrations (500±50 Å diameter) are bridged by a diaphragm and occur in relatively small sieve areas. In contrast to the AV-node and AV-bundle, the non-specialized myocardium is supplied by continuous capillaries. The presence of the fenestrated capillary in the conduction system of the heart may serve to increase both permeability and passive transport capacity.
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  • 19
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    Cell & tissue research 192 (1978), S. 157-166 
    ISSN: 1432-0878
    Keywords: Germ-free mice ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The reported work is the first direct ultrastructural comparison of resident peritoneal macrophages from germ-free and conventional animals. Three groups of mice were studied: germ-free (GF), conventionally-reared under isolation conditions (IC), and conventionally-reared in an open environment (OC). The macrophages from the three groups of animals are closely similar morphologically. Particularly noteworthy are the electron-dense, lysosome-like granules which are numerous in the macrophages of germfree mice and which provide a structural foundation for the presumed microbicidal capability of the phagocytes. Morphometric estimates showed that the “average macrophage” from GF mice is smaller and possesses a smaller, rounder nucleus, a smaller volume fraction of mitochondria and more lysosome-like granules per unit of cytoplasmic volume than the “average macrophage” from conventional mice. Moreover, granules and mitochondria are smaller, on average, in the GF phagocytes than in macrophages from conventional mice. The results suggest that peritoneal macrophages from the germ-free mouse represent, more truly than those from the conventional mouse, the nature of the fully differentiated but as yet unstimulated mononuclear phagocyte.
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  • 20
    ISSN: 1432-0878
    Keywords: Neuroendocrine system ; Galleria ; Ultrastructure ; Reserpine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study concerns the influence of reserpine on the fine structure of peptidergic neurosecretory cells in the pars intercerebralis of Galleria mellonella, and of neurons containing smaller dense-cored vesicles (presumed to be aminergic) localized in the same area of the brain. The drug, administered in doses of 125 μm and 250 μg per g of insect body weight, reduces both the amount and the electron opacity of the dense-cored vesicles with a diameter of 60–80 nm in the neuronal perikarya as well as their terminals. Simultaneously, this treatment evokes an abnormal accumulation of secretory granules within the perikarya of peptidergic neurosecretory cells belonging to three types. This accumulation of secretory material is followed by some changes in the fine structure of these cells. One (fourth) type of neurosecretory cells seems to be insensitive to reserpine action. Participation of the aminergic system in the regulation of the secretory activity of some populations of peptidergic neurosecretory neurons of the insect brain is postulated.
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  • 21
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    Cell & tissue research 192 (1978), S. 341-357 
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Cell types ; Neonate ; Parturient ; Harp seal, Phagophilus groenlandicus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pars distalis of parturient harp seals (Pagophilus groenlandicus) is divisible into three distinct zones based on the major cellular components of the different regions. A clear zonation is lacking in neonate seals, the medial “basophilic wedge” and the anterior gonadotrophic were small and difficult to identify. Five cell types were identified based on cytological characteristics: somatotrophs, mammotrophs, thyrotrophs, gonadotrophs and stellate cells; corticotrophs could not be identified, with any certainty, in any of the preparations, nor could the gonadotrophs be classified into LH, FSH, and ICSH cells. The pars intermedia enlarged during the early post-partum period and was large in the parturient females.
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  • 22
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    Cell & tissue research 192 (1978), S. 391-407 
    ISSN: 1432-0878
    Keywords: Placenta (rat) ; Permeability ; Tracer ; Intercellular junctions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of lanthanum chloride and horseradish peroxidase within the full-term chorioallantoic placenta of the rat was investigated 1 to 20 min after administration of these tracers into the maternal blood circulation. Both tracers rapidly penetrate trophoblastic layer I and diffuse into the interspace between layers I and II. They are localized in extensive infoldings and caveolae of the outer surface of layer II. The syncytial character of layer II is confirmed at this developmental stage of the placenta. There is no vesicular uptake or penetration beyond layer II until 20 min after tracer administration. Our results indicate that trophoblastic layer II is the main barrier in the chorioallantoic rat placenta preventing the permeation of macromolecules from maternal to fetal compartments. With freeze-fracturing, particulate structures of variable arrangement and size are found between adjacent cells of layer I. With goniometric analysis small gaps between the appositions of the membrane are observed. These structures are interpreted as tight and/or gap junctions during stages of assembly or disassembly.
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  • 23
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    Cell & tissue research 192 (1978), S. 409-422 
    ISSN: 1432-0878
    Keywords: Placenta (rat) ; Capillary ; Permeability ; Tracer ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of horseradish peroxidase and lanthanum chloride within the full term chorioallantoic placenta of the rat was examined after administration of these tracers into the umbilical artery. Both tracers rapidly traverse the capillary endothelium. Transendothelial channels, fenestrations and micropinocytotic vesicles provide the main pathways. Intercellular clefts which are either patent or interrupted by leaky intercellular junctions, also contribute to a rapid passage of low and high molecular weight substances. Deep channel-like invaginations, effecting an increase of the exchange area of layer III, are freely accessible to the tracers from the interspace between the capillary endothelium and trophoblastic layer III. The invaginations, however, are not in continuity with the interspace between layers II and III, verifying the syncytial character of layer III. Neither an uptake of the tracers nor a passage across layer III is observed. The main permeability barrier to feto-maternal transfer within the chorioallantoic placenta is localized in the syncytiotrophoblastic layer III. This layer controls the passage of low molecular weight substances and restricts the penetration of high molecular weight substances.
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  • 24
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    Cell & tissue research 186 (1978), S. 241-258 
    ISSN: 1432-0878
    Keywords: Neural lobe ; Anolis carolinensis ; Ultrastructure ; Intermediate lobe control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the neural lobe of the lizard, Anolis carolinensis, was studied after fixation in a threefold aldehyde solution. The neural lobe appeared as narrow vertical diverticula separated from one another and from the pars intermedia by a continuous vascular septum. No nerves passed through this septum. The ependymal, fibrous and external layers were readily recognized. Peptidergic fibres were the main component of the fibrous layer. The peptidergic endings were in intimate contact with the ependymal cells, suggesting that the ependyma mediates the release of neural lobe peptides. The external layer contained ependymal end-feet and numerous aminergic terminals, ending directly on the perivascular basal lamina and/or on the ependymal end-feet. The functional aspects are discussed in terms of intermediate lobe control. The findings suggest that aminergic substances take part in the control of the intermedia, but do not exclude the involvement of peptide hormones.
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  • 25
    ISSN: 1432-0878
    Keywords: Liver ; Teleost ; Ultrastructure ; Lipid ; Vitellogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The female zebrafish is capable of producing mature eggs on the fifth day of each reproductive cycle. During this five-day period the ultrastructure of hepatocytes undergoes several changes. The number of nuclear pores increases rapidly during spawning, followed by a proliferation of RER within 24 h. Two days after spawning, glycogen has disappeared and the liver contains large amounts of lipids. The lipid droplets are closely surrounded by elongated mitochondria. Golgi complexes are abundant, secreting dense bodies. Four days after spawning the hepatocytes tend to regain their pre-spawning appearance. It is suggested that the changes in the hepatocytes, which coincide with special phases of ovarian activity, are related to vitellogenin synthesis. Steroids, especially estradiol-17β, may trigger this process in the liver.
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  • 26
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    Cell & tissue research 186 (1978), S. 327-335 
    ISSN: 1432-0878
    Keywords: Cuticle ; Epidermis ; Chironomus ; Respiration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larval integument of the midge, Chironomus riparius Mg., is unusually thin although it conforms with the normal insect pattern. The cuticle of the post-cephalic segments is about 3 μm thick and overlies an epidermis which has an irregular basal plasma membrane resulting in spaces occurring between it and the basement membrane. The ventral tubuli have a similar epidermis but the cuticle is somewhat thinner. The anal papillae have the thinnest cuticular covering with a uniquely folded epicuticle of variable thickness, and their epidermis has the characteristics of a transporting epithelium. No evidence of pore canals could be found in the cuticle of any part except the head capsule which has a remarkably smooth epicuticle and a distinct layer which may represent the exocuticle. There are no spaces between the basement membrane and basal plasma membrane of the epidermis in the head. Ultrastructural evidence would suggest that gaseous exchange can occur across most of the post-cephalic integument.
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  • 27
    ISSN: 1432-0878
    Keywords: Area postrema ; 6-Hydroxydopamine ; Degenerative changes ; Ultrastructure ; Cynomolgus and squirrel monkeys
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 6-Hydroxydopamine (6-OH-DA) has been shown to produce degenerative changes in noradrenergic nerve terminals and preterminals in the CNS following intracisternal, intraventricular or direct injection into the brain parenchyma. Systemic injection of 6-OH-DA is known to result in degenerative changes in noradrenergic terminals in the peripheral nervous system. However, only a few studies have been carried out on the effects of systemic injections of 6 OH-DA on noradrenergic terminals in the CNS. In the present study cynomolgus and squirrel monkeys were injected intravenously on two successive days with total doses of 350mg/kg and 150 mg/kg of 6-OH-DA, respectively, and sacrificed at 2 and 24 h following the second injection. Degenerative changes in the area postrema (AP) neurons in all injected animals were characterized by a generalized increase in electron density of cytoplasmic elements in axonal terminals and preterminals. Multilamellar bodies, clusters of clear and dense core vesicles, increased numbers of secondary lysosomes, and an increase in the number of glycogen granules were observed in these structures. In astrocytes the amount of glycogen increased markedly in injected animals, but no other glial alterations were observed. The number of mast cells in the AP was greater in injected than in noninjected animals, both in the perivascular spaces (PVS) and in parenchymal locations. Cell processes in the PVS were occasionally observed to contain electron dense bodies, and degenerative changes were seen in supraependymal processes in some injected animals.
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  • 28
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    Cell & tissue research 187 (1978), S. 135-146 
    ISSN: 1432-0878
    Keywords: Osteodentine ; Anarhichas lupus ; Ultrastructure ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le tissu dentinaire d'Anarhichas lupus s'est révélé être une ostéodentine vasculaire. Les études en MET, MEB et diffraction X montrent l'hétérogénéité de ce tissu. L'aspect désordonné des fibres de collagène, incomplètement minéralisées (leur striation est encore bien visible), explique la complexité de la répartition des cristaux puisqu' elles en déterminent l'ordonnance. La minéralisation imparfaite du tissu, dont témoignait déjà la striation visible du collagène, est confirmée par l'analyse des poudres en diffraction X (la cristallinité de l'ostéodentine vasculaire est nettement inférieure à celle de la couche de tissu dentaire périphérique) et par l'examen en MET de haute résolution, aucun réseau cristallin n'ayant pu être mis en évidence. L'ostéodentine, l'os basal et l'os profond ont en commun une phase minérale, avec une organisation plus ou moins bonne, différente du système des apatites.
    Notes: Summary TEM, SEM and X-ray diffraction analysis demonstrate the heterogeneity of the dentinal tissue of Anarhichas lupus, a vascular osteodentine. The disordered aspect of collagen fibres, incompletely mineralized (the periodical striation being still visible), explains the scattered distribution of crystallites since they are responsible for their arrangement. The low degree of mineralization revealed by the visible collagen striation is confirmed by X-ray diffraction analysis (the crystallinity of vascular osteodentine being much lower than that of the peripheral dental tissue) as well as by high resolution TEM, since no lattice planes could be observed. Osteodentine, supporting bone and proper bone have in common a mineral phase, more or less organized, different from the apatite system.
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  • 29
    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Epithelium ; Renewal ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary The intestinal absorptive epithelium of starved and fed fish has been studied electron microscopically. After feeding, cells of the proximal segment of the intestine show morphological characteristics of lipid absorption. Absorptive cells in the middle segment contain many pinocytotic vesicles in both fasted and fed specimens. Absorption of protein macromolecules is supposed to be one of the main functions of this part of the gut. In the most caudal part of the intestine, absorptive cells carry relatively few and short microvilli. The proximal and distal segments show structural indications of a function in osmoregulation. The renewal of the epithelium has been studied with light microscopic autoradiography, using tritiated thymidine. The intestinal mucosal fold epithelium represents a cell renewal system. The cells proliferate at the base of the fold and migrate towards the apex in 10–15 days at 20° C. The functional absorptive cells proved to be generally present in the intestinal epithelium, including the proliferative area. Undifferentiated cells have not been identified. The results will be compared with data on absorption of lipid and protein macromolecules in teleostean and mammalian intestines and with descriptions of the cell renewal system in the mammalian intestine.
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  • 30
    ISSN: 1432-0878
    Keywords: Neuron ; Glial ; (Insect, Chironomus riparius) ; Extracellular space ; Perineurium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the neural sheath, glial cells and neurons in the brain of the neoimaginal male Chironomus riparius is described. The neural sheath comprises a neural lamella and underlying perineurium. The neural lamella consists of an amorphous matrix in which fine fibrils occur. The perineurium is composed of two cell types forming a continuous layer around the brain. The subjacent cortical layer, composed of the cell bodies of neurons and glial cells, varies considerably in thickness and surrounds the centrally located neuropiles. Three types of glial cells are distinguished on the basis of their positions and appearances. Five types of neurons are described which differ in size and relative frequency of organelles. Four types of axons, including those of neurosecretory cells, are distinguished by their size and content.
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  • 31
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    Cell & tissue research 188 (1978), S. 189-204 
    ISSN: 1432-0878
    Keywords: Neural lobe of hypophysis ; Hibernating mammals ; Ultrastructure ; Neurosecretory granules ; Whorls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'ultrastructure de la posthypophyse du Lérot a été examinée à différents stades du cycle annuel de ce rongeur hibernant. Il n'a pas été observé de différences évidentes entre les stades étudiés, et sont donc présentées ici les caractéristiques générales retrouvées chez tous les animaux. Les axones neurosécréteurs et leurs terminaisons peuvent être divisés en deux catégories suivant l'aspect des grains de neurosécrétat et des microvésicules présents. Le premier type contient des grains arrondis, à contenu d'apparence homogène, avec des microvésicules rondes. Dans les autres axones, les grains sont de forme variable, souvent allongés, et leur contenu présente deux sortes d'organisations cristallines; les microvésicules y sont en majorité aplaties. Considérant comme improbable que cette dualité résulte seulement d'un artefact, trois hypothèses sont envisagées. La dualité d'aspect des grains peut être liée à leur contenu en hormone (ocytocine ou vasopressine); ou bien l'aspect des grains peut correspondre à leur degré de maturation. Il est possible aussi que ces explications soient toutes deux valables. Par ailleurs, les pituicytes du Lérot contiennent fréquemment un réticulum endoplasmique organisé en lamelles concentriques (whorls). La signification de ces formations reste pour l'instant obscure.
    Notes: Summary Ultrastructural examination of the posterior pituitary of the garden dormouse (Eliomys quercinus L.) was carried out at different times in the annual cycle of this hibernating rodent. Obvious differences between experimental groups have not been observed, and the results presented here must be considered as general features of the garden dormouse posterior pituitary. Neurosecretory axons and endings can be divided into two types, according to different aspects of neurosecretory granules (NSG) and microvesicles (MV). One type contains spherical NSG with homogeneous cores and round MV. In the other type, NSG have various, often elongated, shapes. Their content shows two types of crystalline structures and most of the MV have flattened aspects. As it is very unlikely that this duality in NSG is a result of an artefact of fixation, three hypotheses are presented as explanation. The duality of NSG might be related either to their hormonal content (oxytocin or vasopressin) or to their degree of maturation. Moreover, both explanations may be valid. In the species studied, pituicytes often contain concentric lamellar structures of the endoplasmic reticulum (whorls), the significance of which remains obscure.
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  • 32
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    Cell & tissue research 188 (1978), S. 409-426 
    ISSN: 1432-0878
    Keywords: Ovary ; “Nude” mouse ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary The ovarian follicles of juvenile (15-day and 21-day old), pubescent (28-day old) and sexually mature (45-day old) “Nude” mice have been compared to those from normal NMRI mice of the same age and breeding groups. At the electron microscopical level, some differences were observed in both follicular cells and oocytes. In the follicular cells, the following alterations could be seen in the “Nude” ovaries: (1) the differentiation between clear and dark cells, normally not occurring before the age of 21 days, was already present in the 15-day old “Nude” mice and (2) the follicular intercellular spaces were frequently dilated, possibly because of a contraction of the cells, even in the small growing follicles of the bilaminar type in the athymic animals. The “Nude” oocytes could be characterized by (1) a precocious appearance and an early disappearance of the nuage material, (2) a nearly complete absence of micropapillae on the oolemma, (3) a dense and disseminated aspect of their Golgi complexes, (4) the presence of a large amount of multivesicular bodies and (5) of tiny (about 30 nm) dense membrane-bounded particles in their ooplasm. These differences are discussed in relation to the possible interference of congenital athymia with the development of the hypothalamo-pituitary-gonadal axis. However, the influence of the reduced immunological responsiveness of the “Nude” mice on their ovarian development cannot be excluded for animals raised in a normal — and consequently infected — environment.
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  • 33
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    Cell & tissue research 188 (1978), S. 481-490 
    ISSN: 1432-0878
    Keywords: Fat body ; Cockroach ; Reproductive cycle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The central fat body of the ovoviviparous cockroach Nauphoeta cinerea was studied during the first reproductive cycle of the female by means of light microscopy, autoradiography and electron microscopy. Comparative studies in larval stages were also undertaken. The fat body of Nauphoeta contains a large amount of lipid droplets and the remaining cytoplasm is very scarce. The cytological cyclicity of the fat body is consistent with the known biochemical rhythms of vitellogenin production. The proteosynthetic apparatus appears about 3 days after imaginal ecdysis, along with vitellogenin. The ribosomal endoplasmic reticulum (RER) shows a tremendous increase by the 7th day of the first cycle. The most active period of vitellogenin production lasts from day 7 to day 12. The proteosynthetic apparatus then returns to an inactive stage and disappears. This inactive condition lasts to the end of the gestation period. The autoradiographic results are consistent with the cytological features.
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  • 34
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    Cell & tissue research 189 (1978), S. 347-353 
    ISSN: 1432-0878
    Keywords: Vitelline membrane ; Chorion ; Ultrastructure ; Curculionidae
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    Topics: Biology , Medicine
    Notes: Summary The follicle cells of Foucartia squamulata are involved in the formation of both vitelline membrane and chorion. Precursors for these egg coverings are synthesized by the rough endoplasmic reticulum and condensed within dictyosomes. The vitelline membrane and the chorion appear on the oocyte surface simultaneously, which is an unusual phenomenon for insects. The follicular epithelium has not been found to contribute to vitellogenesis in the species under study.
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  • 35
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    Cell & tissue research 189 (1978), S. 365-374 
    ISSN: 1432-0878
    Keywords: Previtellogenesis ; Oocyte ; Ultrastructure ; Acerentomon gallicum ; Protura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary At the onset of previtellogenesis, the oocytes of Acerentomon gallicum begin to grow and increase their content of organelles. The nuage material in the oocytes at first increases in amount, then declines gradually to disappear completely from oocytes that have attained 50 μm in diameter. During the growth period, new dictyosomes, mitochondria and ribosomes appear. Numerous vesicles become detached from the cell membrane and subsequently fuse into cisternae, thus forming extensive complexes of the rough endoplasmic reticulum. In oocytes with diameters between 50 and 100 μm the Golgi complexes show a considerable increase in activity, and many lamellar bodies arise from mitochondria that have undergone specific transformation.
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  • 36
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    Cell & tissue research 189 (1978), S. 549-554 
    ISSN: 1432-0878
    Keywords: Tormogen cell ; Receptor-lymph space ; Chemoreceptor ; Ultrastructure ; Histochemistry ; Calliphora (Insects)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary (1) The basiconic sensilla on the antennae of Calliphora resemble other insect epidermal sensilla; one or several bipolar sense cells are surrounded by three non-neural cells. (2) The apical cell membrane of the tormogen cell(one of the three accessory cells) forms microvilli coated internally with particles. (3) In the (extracellular) outer receptor-lymph space hyaluronic acid can be demonstrated histochemically. (4) Demonstration of non-specific alkaline phosphatase, Mg2+-activated ATPase, and the presence of mitochondria in the apical part of the tormogen cell suggest active transport processes through these cells into the outer receptor-lymph space.
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  • 37
    ISSN: 1432-0878
    Keywords: T-system tubules ; Glycerol procedure ; Structure-activity relationship ; Ultrastructure ; Astacus fluviatilis
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    Topics: Biology , Medicine
    Notes: Summary The development of ultrastructural changes in the T-system of isolated muscle fibres of the crayfish by the glycerol procedure is described in correlation with the dissociation of excitation-contraction (E-C) coupling as well as with recoupling of the E-C link. The sequence of events in the process of disconnection of the tubules is as follows: dilation of the T-system tubules, disconnection of the constricted tubular segments from the surface membrane and from the T-system vesicle, disappearance of the lumen and its disintegration. The decoupled state is characterised by the presence of round vesicles uniformly distributed in the entire volume of the fibre. The volume of vesicles accounts well for the residual postglycerol volume increase (15%) of the muscle fibres. Functional and structural recovery can be induced by reapplication of glycerol to fibres decoupled and vesiculated with concentrations of glycerol≦300mmol · l-1 in crayfish saline. The restitution starts with the organisation of the material of the disintegrated connecting segment of the T-system tubule into small vesicles which coalesce to form the tubule from the vesicular site. At the same time the surface membrane is invaginated toward the vesicle, thus forming the tubule from the surface membrane site. Recovery starts already in the first minute after application of glycerol and is completed within approximately 15min.
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  • 38
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    Cell & tissue research 189 (1978), S. 31-40 
    ISSN: 1432-0878
    Keywords: Pituitary cell clone ; LHRH-Sepharose ; Gonadotrophs ; Hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 2A8 clonal cells derived from the epithelium of Rathke's pouch of fetal rats were cultured in growth medium supplemented with fresh rat serum, median-eminence extract and l-thyroxine. Then, in order to isolate gonadotrophs, cyanogen bromide-activated Sepharose which was conjugated with LHRH (LHRH-Sepharose) was added to the culture medium. Fourteen days after incubation of 2A8 cells with LHRH-Sepharose, agranular and granular cells were rapidly bound to LHRH-Sepharose when fresh serum had previously been added in the medium. The cytoplasm of granular cells that were bound to LHRH-Sepharose contained spherical secretory granules (200–250 nm in diameter). These cells were similar in morphology to the FSH and LH gonadotrophs described by Kurosumi (1968). Moreover, many of them appeared as hypertrophied cells that resembled “castration” cells. These results demonstrate that LHRH conjugated to Sepharose can be used to separate gonadotrophs from other 2A8 cells, and it is suggested that the hypertrophy of some cells might be due to persistent stimulation by LHRH which is likely bound to receptors on the cell membrane.
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  • 39
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    Cell & tissue research 189 (1978), S. 41-51 
    ISSN: 1432-0878
    Keywords: Herring bodies (rat) ; Colchicine ; Cold ; Neurosecretion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A study of the morphology of Herring bodies of the posterior pituitary lobe of rats treated with colchicine and/or exposed to low temperatures has been performed. After treatment with colchicine (20 μg in distilled water injected intracisternally) a predominance of Herring bodies with a large number of small “synaptic-like” vesicles surrounded by neurosecretory granules is found. Exposures to low temperature (4–6° C) result in an increase in the neurosecretory material and the Herring bodies show many neurosecretory granules of different densities. After treatment with colchicine and subsequent exposure to low temperatures, the Herring bodies are characterized by having a great number of autophagic bodies which become more numerous as the length of the exposure is increased; later autophagic vacuoles and lamellar bodies become evident.
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  • 40
    ISSN: 1432-0878
    Keywords: Connective tissue sheath ; Periplaneta ; Ultrastructure ; Histochemistry
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    Description / Table of Contents: Résumé La gaine conjonctive épaisse entourant l'intestin moyen de la Blatte Periplaneta americana a été étudiée en faisant appel à la microscopie photonique, électronique et l'histochimie. Cette couche conjonctive, reliée à l'épithélium mésentérique par une lame basale, traversée par des faisceaux musculaires, des trachées et des nerfs, contient de très nombreuses fibrilles de collagène, des fibrilles élastiques, des fibroblastes et des hémocytes. Au cours des premiers stades le matériel conjonctif est élaboré par des fibroblastes. Différentes réactions, en particulier le bleu alcian, la métachromasie et les digestions enzymatiques ont montré la présence de glycosaminoglycanes. La présence d'acide hyaluronique à tous les stades, l'apparition et l'augmentation des composés sulphatés ainsi que la présence de glycoprotéines ont été mises en évidence.
    Notes: Summary The thick layer of collagenous connective tissue around the mesenteron of the cockroach Periplaneta americana has been examined by light microscopy, electron microscopy and histochemical techniques. This sheath, connected to the mesenteric epithelium by a basal lamina and traversed by longitudinal and circular musculature, tracheae and nerves, contains numerous collagen fibrils, elastic fibers, fibroblasts and rare hemocytes. Development starts during the first instars with the production of connective tissue material by fibroblasts. Glycosaminoglycans have been observed with the use of various histochemical reactions, in particular alcian blue staining, metachromasia and enzymatic digestion. The reactions indicate the presence of hyaluronic acid in the various instars, the appearance and increase of sulphated components during development, and the presence of neutral glycoproteins.
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  • 41
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    Cell & tissue research 192 (1978), S. 319-326 
    ISSN: 1432-0878
    Keywords: Periderm granules ; Regenerating feather ; Ultrastructure ; Jungle fowl
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    Topics: Biology , Medicine
    Notes: Summary Periderm granules in the support cells of regenerating feathers of mature male Jungle Fowls were studied ultrastructurally and histochemically. Histochemical results showed the absence of carbohydrate and lipid, and the presence of protein in the periderm granules. The periderm granules were measured at successive levels of feather regeneration. The mean size of the periderm granules increased significantly as the regenerating feather matured, and this observation was suggestive of a storage function, perhaps of surplus or waste protein. The cells in which the periderm granules are found also contain glycogen. There are numerous desmosomal junctions on their interdigitating plasma membranes. These transient cells may collect waste, provide nutrition, and serve as a protective barrier for the definitive cells of the regenerating feather.
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  • 42
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    Cell & tissue research 192 (1978), S. 359-361 
    ISSN: 1432-0878
    Keywords: Spermatids ; Human ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary Osmiophilic granules with surrounding vesicles resembling flower-like structures occur transiently during the differentiation of human spermatids. These organelles are incorporated into the residual bodies when mature spermatids are released from the germinal epithelium.
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  • 43
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    Cell & tissue research 186 (1978), S. 499-506 
    ISSN: 1432-0878
    Keywords: Fat body ; Aedes aegypti ; Vitellogenin ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the fat body of Aedes aegypti was followed from emergence through a blood meal. Changes in the volume of protein granules and lipid droplets were also examined. The relationship of these events to the known endocrinology of vitellogenin synthesis in mosquitoes is discussed.
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  • 44
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    Cell & tissue research 188 (1978), S. 205-215 
    ISSN: 1432-0878
    Keywords: Myocardium ; Mouse ; Ultrastructure ; Leptofibrils ; Desmosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The papillary muscle of the heart of adult white mice is investigated. Intrafibrillarly located leptomeric fibrils, frequently encountered in the Z-band region of the myofibrils. The leptomeric fibrils are always running in a transverse direction and often in close proximity to the transverse tubules (which are also located at this level). There seems to be a close connection between the dense striae of the leptofibrils and the Z-bands of ordinary myofibrils. The leptomeric fibrils are spindle-shaped and have a length varying between 0.6 and 1.2 μm. The banding periodicity of the fibrils is approximately 0.16 μm. Occasionally desmosomes are observed in the T-tubule system.
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  • 45
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    Cell & tissue research 187 (1978), S. 1-24 
    ISSN: 1432-0878
    Keywords: Insect sensillum ; Mechanoreceptor ; Development ; Ultrastructure ; Gryllus bimaculatus
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The filiform hairs, mechanoreceptors of Gryllus, pass through six developmental stages during the last larval stage. The cytoplasm of their sense cells suggests intensive synthesis of protein for cellular metabolism and intercytoplasmic exchange of material via glial evaginations. Ultrahistochemical tests demonstrated acid phosphatase in the lysosomes as well as in components of the Golgi apparatus. There was no significant change in the appearance of the sense cell cytoplasm, indicating a maintained functional state also during molting. The new cuticular apparatus is formed after apolysis by the three enveloping cells. Formation of the replacement hairs is initiated by a cytoplasmic outgrowth of the trichogen cell. During morphogenesis of the new hair, the microtubules serve as a cytoskeleton and probably control the flow of vesicles, which contain phenol oxidase, also demonstrated in the Golgi apparatus, and are incorporated into the new cuticle. Bundles of microfibrils are involved in the surface sculpturing of the replacement hair. The trichogen cell also forms a number of structural elements, e.g. the “cup” and “strut” marked geometric peculiarities of which indicate that they are important in the spatial orientation of the dendrite and thus also in transduction. Reduction of the apical cell membrane of the tormogen cell after apolysis permits unrestricted growth of the new hair into the exuvial space. The tormogen cell participates in the formation of the joint membrane, parts of the socket and the articulation of the hair.
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  • 46
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    Cell & tissue research 187 (1978), S. 25-43 
    ISSN: 1432-0878
    Keywords: Lactation ; Prolactin ; Secretion ; Caseins ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les effets de la prolactine, sur la sécrétion des protéines du lait, ont été étudiés grâce à des incubations de tranches de glandes mammaires de lapines en lactation. Dès 15min après l'addition de l'hormone au milieu d'incubation, la morphologie de la cellule est modifiée: le volume relatif des vésicules et des saccules Golgiens est fortement augmenté. Lorsque la prolactine est rajoutée, immédiatement après un marquage en 〈pulse〉 des protéines (pendant 3 min par la L-leucine 3H), elle provoque, en une heure, une augmentation de la sérétion des caséines radioactives dans le milieu d'incubation. Cette augmentation de la quantité de caséines sécrétées ne provient ni d'une augmentation du transit intracellulaire des protéines néosynthétisées (étudié par autoradiographie en Microscopie Electronique), ni d'une augmentation d'incorporation des acides aminés (mesurée par l'incorporation d'acides aminés non métabolisables), ni d'une augmentation de la synthèse protéique totale, dans le délai d'une heure. Les relations possibles entre l'action de la prolactine sur l'aspect morphologique d'un organite cellulaire tel que l'appareil de Golgi et sur la sécrétion des caséines sont discutées.
    Notes: Summary Effects of prolactin on the secretion of milk proteins have been investigated by incubating mammary tissue fragments from lactating rabbits. Within 15min of adding the hormone to the incubation medium, cell morphology is modified: the relative volume occupied by the Golgi region is greatly increased. When prolactin is added immediately after a pulse labelling of proteins (3 min with 3H-L-leucine), the amount of labelled caseins secreted during one hour is significantly increased. This increase proceeds neither from an acceleration of intracellular transit of caseins (as shown by electron microscopic autoradiography) nor by an enhancement of amino acid uptake (as measured by incorporation of non-metabolizable amino acids) nor by an increase of overall protein synthesis, during the first hour. The action of prolactin on the morphology of such subcellular organelles as the Golgi apparatus and its influence on casein secretion are discussed.
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  • 47
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    Cell & tissue research 187 (1978), S. 79-96 
    ISSN: 1432-0878
    Keywords: Crustacean hemocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fine structural analysis of hemocytes recovered from the pericardial sinus of the blue crab (Callinectes sapidus) demonstrates that hyaline cells, intermediate cells, and granuloyctes are present in the hemolymph. A detailed consideration of their shared and differing cytological features suggests that the various blood cells represent different stages of cytogenesis along a common or single path of cellular differentiation. The potential functional complexity of the hemocytes is attested to by the occurrence within their cytoplasm of three and/or possibly four morphologically distinct types of inclusion bodies, and other membrane-bounded compartments (e.g., lysosome-like structures, autophagic vacuoles, peroxisome-like bodies) whose function is unknown. Preliminary examination of the well-developed Golgi organelle in the intermediate cells and granulocytes indicates its probable participation in the elaboration of the inclusion bodies; however, the details of its role in granulogenesis and in the known plurifunctional capacities of these cells remain obscure.
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  • 48
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    Cell & tissue research 187 (1978), S. 129-134 
    ISSN: 1432-0878
    Keywords: Adrenal cortex (Pig) ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Unusually large mitochondria with few cristae were observed in the cells of the boundary layer between the zonae fasciculata and reticularis of the pig adrenal. These mitochondria occasionally contained parallel arrays of beaded filaments which appeared to be composed of repetitive electron opaque particles, measuring 10 to 11 nm in diameter. The possibility that these filaments are arranged in closely packed arrays of tubular structures with a central filament is discussed.
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  • 49
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    Cell & tissue research 187 (1978), S. 333-353 
    ISSN: 1432-0878
    Keywords: Midgut ; Centropages typicus (Copepod, Calanoid) ; Structure ; Ultrastructure ; Digestive function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary From a structural study of the midgut of Centropages typicus, three main zones presenting different cellular associations may be defined. The ultrastructural study carried out allows us to distinguish several cell types. The four principal cell categories (E, R, F and B) show a more or less marked resemblance with those identified in the Malacostraceans, especially in the hepatopancreas of Decapods. The three types R, F and B, which are subdivided according to their localization (R and R′) or their developing stages (F1, F2; B1 to B5), are recognized by the following characteristics: R-cells with smooth endoplasmic reticulum and high microvilli (zones I and III); F-cells with rough endoplasmic reticulum and short or spherical microvilli (zones I and II); B-cells with a large vacuolar apparatus made up of lysosome-like dense bodies associated with vacuoles originating from pinocytosis (zone II). From the comparisons of morphological, ultrastructural and histochemical results concerning Centropages typicus with author's data, we propose and discuss these functions for the three principal cell types: synthesis and secretion of pre-digestive enzymes (F1 and F2-cells); enzyme synthesis, intracellular digestion and extrusion (B1 to B5-cells); absorption (R and R′-cells).
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  • 50
    ISSN: 1432-0878
    Keywords: Thyroid ; Ultrastructure ; Hypophysectomy ; TSH- and prolactin treatment ; Notophthalmus viridescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the newt, Notophthalmus viridescens, hypophysectomy results in progressive atrophy of the thyroid cells to the point of irreversible degeneration. After exclusive TSH-stimulation of hypophysectomized newts, increased endocytotic activity of the follicular epithelium is observed. Prolactin stimulation under the same conditions prevents atrophy but does not result in increased cell activity, as expressed by the reduced amount of microvilli and the lack of endocytotic activity. Combined TSH- and prolactin stimulation also results in cell activation, but the activation level of exclusively TSH-stimulated cells is not reached. Although prolactin prevents cellular atrophy and degeneration of the follicular epithelium, it reduces the TSH-induced activation of the thyroid epithelium.
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  • 51
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    Cell & tissue research 187 (1978), S. 479-488 
    ISSN: 1432-0878
    Keywords: Embryonic hemocytes ; Insecta ; Oncopeltus fasciatus ; Differentiation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hemocytes of Oncopeltus differentiate rather early during embryogenesis. They are segregated by the mesoderm soon after its formation (about 50h after egg deposition). Newly segregated hemocytes show the “typical” features of “embryonic” cells: many free ribosomes, a few strands of rough ER, the cisternae of which are considerably distended, electron lucent vacuoles around the periphery, and glycogen deposits. A few hours thereafter the hemocytes undergo striking subcellular changes. First, glycogen, electron lucent vacuoles and rough ER disappear and phagocytotic activity can be observed. Golgi complexes become well expressed and give rise to electron dense vesicles which fuse to larger bodies. Then, rough ER develops again and occupies large areas of the cytoplasm. Its cisternae are often considerably distended by proteinaceous secretions. All hemocytes undergo the same steps of differentiation. Embryonic hemocytes obviously play a decisive role in the elimination of waste products, in particular of tissue debris that results from programmed cellular death. The significance of the conspicuous protein secretions is not fully understood. They may participate in the deposition of the acellular connective tissue, or may have some of the other functions ascribed to insect blood cells. Larvae and imagines of Oncopeltus have four types of hemocytes, which agree rather well with those found in Rhodnius (Lai-Fook, 1970). All embryonic hemocytes, aside from the newly segregated ones, represent plasmatocytes but, unlike plasmatocytes of postembryonic stages, they contain no large inclusion bodies. Newly segregated embryonic hemocytes, in addition to their “typical embryonic” features, have some similarities with larval and adult prohemocytes. Oenocytoids and granulocytophagous cells are absent in the embryo. Some aspects concerning the differentiation and classification of hemocytes are discussed.
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  • 52
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    Keywords: Suboesophageal ganglion (cricket) ; Paramedial neurosecretory cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paramedian neurosecretory cells (PNC) (A-type) in the suboesophageal ganglion of the cricket, Teleogryllus commodus (Walk.), have been studied by electron microscopy. In control animals (10 day-old virgin females) three different cell stages could be distinguished: Stage 1 shows a variable content of elementary granules and characteristics of actively synthesising cells. Stage 2 is characterised by the presence of numerous fusion bodies, which are formed by the coalescence of elementary granules, presumably for storage purposes. In stage 3 granules are degraded in lysosomes (?). While the production of material rich in cysteine increases after ovariectomy (Dürnberger et al., 1978), the fine structure of the cells is essentially unchanged. The only noted differences are an increased lysosomal synthetic activity and the existence of stages intermediate between 2 and 3, which were never found in control animals. The functional significance of the different stages is discussed.
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  • 53
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    Cell & tissue research 188 (1978), S. 133-141 
    ISSN: 1432-0878
    Keywords: Pineal organ, rat ; Ultrastructure ; Gonadotropic hormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The influence of gonadotropic hormones on the ultrastructure of rat pinealocytes was studied. Human chorionic gonadotropin (HCG) as well as pregnant mare serum gonadotropin (PMSG) caused a marked activation of pinealocytes. It is characterised by a conspicuous proliferation of the granular endoplasmic reticulum and Golgi apparatus as well as an increase in number of dense core vesicles, mitochondria, dense bodies, subsurface cisternae and vesicles in the terminal buds of pinealocyte processes. The changes after HCG administration were more pronounced than after PMSG.
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  • 54
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    Keywords: Adrenal ; Steroidogenesis ; Inihibitor ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In concert with studies of the effects of various pharmacologic inhibitors of corticosteroidogenesis on adrenocortical morphology, U-8113, an analog of amphenone B, was administered daily to Sprague-Dawley rats for 7, 14, 21 or 30 days. The primary morphological responses involved increases in adrenal weight, width of zona fasciculata, width of zona reticularis, intracellular lipids, mitochondrial size, mitochondrial vacuolation and crystalline-like inclusions, small coated vesicles, lysosomes, autophagic vacuoles and cholesterol ester clefts. In particular, the increases in lysosomes, coated vesicles and autophagic vacuoles containing morphologically altered mitochondria were considered reflective of mechanisms designed to maintain cellular integrity amidst functional impairment. Lipid analysis revealed marked increases in cholesterol esters and phospholipids, supportive of morphological observations. When permitted a 14 day recovery period following either 14 or 30 days of inhibitor therapy, most fine structural alterations and lipid derangements were diminished, and the cells approximated normal parameters.
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  • 55
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    Cell & tissue research 190 (1978), S. 337-347 
    ISSN: 1432-0878
    Keywords: Respiratory epithelium ; Anguis fragilis ; Pneumonocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium covering the respiratory portion in the lung of the slow-worm (Anguis fragilis) has been studied by electron microscopy. The epithelium is composed of two different types of pneumonocytes. The type I pneumonocytes are roughly squamous and their cytoplasmic sheets spread over relatively large areas of the septal walls. These cytoplasmic sheets are attenuated in regions where they overlie septal capillaries; they usually have extensive areas of contact with adjacent cells. The type II pneumonocytes are also squamous but are more compact and possess more organelles. Their osmiophilic inclusion bodies are especially conspicuous. Most of their microvilli are concentrated on the surfaces of cytoplasmic “hillocks”. Deposits of membranous material are present in the air sacs. The morphological evidence suggests that the type II cells of Anguis secrete surface-active material.
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  • 56
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Regeneration ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary Electron microscopic studies were made of the regeneration of minced smooth muscle of the vas deferens of the guinea-pig 3 days to 15 weeks after operation. At 3–5 days the mince contained degenerating smooth muscle cells and dedifferentiating cells showing characteristics of embryonic smooth muscle cells: numerous free ribosomes, well developed rough endoplasmic reticulum and Golgi apparatus with few peripherally placed myofilaments associated with dense bodies. During the first two weeks of regeneration, scattered cells surrounded by debris and collagen were separated by a large extra-cellular space. After three weeks, extracellular space was reduced to near normal values. Regenerating cells had a shorter length than normal cells, but during later stages of regeneration they showed an increase in diameter. Muscle effector bundles began to form after 2 to 3 weeks. Initially there were large gaps between the muscle cells, but at later stages of bundle formation, the extracellular space between the muscle cells was much reduced. From 3 weeks, arterioles appeared between the smooth muscle bundles in the regenerating areas. Regeneration of individual smooth muscle cells was complete by 15 weeks after the operation.
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  • 57
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    Keywords: Pinealocytes ; Golden mole ; Secretory process ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les pinéalocytes de la glande pinéale de la Taupe dorée Amblysomus hottentotus (Mammifère aveugle et vivant toujours dans une obscurité complète) examinés au microscope électronique ont été comparés à ceux d'autres Mammifères. Une seule population de pinealocytes a été observée. Mitochondries, ribosomes, réticulum endoplasmic granulaire, inclusions lipidiques et rares structures lysosomiales sont présents dans le périkaryon. De nombreux grains de glycogène formant le plus souvent de typiques “accumulations” ont été fréquemment observés associés à des vacuoles. Un grand nombre de vésicules granulaires est la caractéristique première des pinéalocytes. Un phénomène d'excrétion, caractérisé par une dissolution in situ du coeur dense, a été observé. L'importance physiologique de ces vésicules granulaires est discuté.
    Notes: Summary The ultrastructure of the pinealocytes of the golden mole (Amblysomus hottentotus), a blind subterranean mammal living in complete darkness, was examined and compared with that of pinealocytes of other mammals. On the basis of the presence of granular vesicles and glycogen granules, only one population of pinealocytes was found. Large mitochondria, ribosomes, lipid inclusions and scarce lysosomes were observed in the perikaryon. Numerous glycogen granules, often forming typical accumulations, were frequently found to be associated with typical vacuoles. An extraordinary large number of granular vesicles is characteristic of the golden mole pinealocyte. Phenomena of excretion of compound(s) stored in the granular vesicles were identified. Morphologically this is characterized by dissociation of its granular core in situ while its limiting membrane is preserved. The physiological significance of the secretory process characterized by the formation of these granular vesicles is discussed.
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    Cell & tissue research 191 (1978), S. 101-114 
    ISSN: 1432-0878
    Keywords: Sperm host glands ; Quail (Coturnix coturnix jap.) ; Ultrastructure ; Ultracytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and ultrahistochemical studies were performed on the uterovaginal sperm host glands of the quail (Coturnix coturnix japonica). The proximal parts of the glandular necks are lined by a pseudostratified epithelium, consisting of high columnar ciliated cells and small, irregular shaped, basal cells. The true glandular epithelium is composed only of columnar cells with microvilli on their luminal end. A characteristic luminal feature is a large lipid droplet in the perinuclear region. In the subplasmalemmal region numerous tubular profiles are seen which could represent a cellular resorption system. To evaluate the absorptive capacity of the Uterovaginal sperm host glands, tracer studies with HRP, ferritin, lanthanum and ruthenium red were undertaken. Since between 5 min and 3 h after injection no absorption could be found with the techniques mentioned, it is suggested that phagocytosis of spermatozoa by the glandular epithelium is not likely to occur.
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  • 59
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    Cell & tissue research 191 (1978), S. 233-247 
    ISSN: 1432-0878
    Keywords: Nervous system ; Pluteus ; Ultrastructure ; Echinoderms ; Strongylocentrotus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Tissues that have the ultrastructural characteristics of nervous tissues are associated with ciliary and muscular elements of the pluteus larva of Strongylocentrotus purpuratus. The nerve cells are found along the margins of the ciliary bands, which are composed predominantly of spindle-shaped ciliated cells. The nerve cells contribute axonal processes to a tract of axons, which runs at the base of the ciliary band throughout its length. Axonal tracts, in the esophagus, lie beneath the circumesophageal muscles. Branched microvilli, which have been interpreted as sensory receptors, are located on the oral side of the main ciliary band and connect with the nerve cells in the ciliary band. The nervous structures described here, and other tissues of the pluteus that have been previously described as nervous, are compared on the basis of their association with receptor and effector organs, and their ultrastructural characteristics.
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  • 60
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    Cell & tissue research 193 (1978), S. 219-229 
    ISSN: 1432-0878
    Keywords: Multilamellar bodies (human lung) ; Surfactant ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Normal tissues from human lungs were dehydrated through Epon 812 resin to retain many of the lipids and carbohydrates in thin section. The three-dimensional structure of the multilamellar body was determined. The paired layer of phospholipid heads (PH) is 36Å thick; the layer of fatty-acid tails (FA) is 31Å, the same as reported previously for non-human primates and rodents. The human multilamellar body is apparently unique: the lamellae of the major focus divide into two or three lamellae; the matrix material of the core is without vesicular bodies and a projection core is present. When compared with those of the rat, human tissues contain a greater number of lamellar foci and fewer lamellae per focus. The presence of a peripheral layer of lamellae, an ever-present external limiting membrane, and the fusion of multilamellar bodies are also characteristic. Tubular myelin surfactant has the same appearance as in other mammals. Multilamellar bodies were observed in direct communication with Golgi vesicles. Their origin from multivesicular bodies and their maturation through secretion and exocytosis were demonstrated. Untransformed multilamellar bodies in the alveolar space demonstrated three periodicities (P): (1) compact regular lamellae, PH = 36Å, FA = 31Å, P = 66Å; (2) compact broad lamellae, PH = 72Å, FA = 22Å, P = 94Å; (3) loose lamellae, PH = 36Å, FA = 36Å, FA = 31Å with a variable interlamellar space.
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  • 61
    ISSN: 1432-0878
    Keywords: Striated muscle ; Proteins ; Radioautography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The elaboration and distribution of newly formed proteins in the striated muscle of 21-day-old mice were investigated by quantitative radioautography at intervals between 2 and 240 min after intravenous injection of tritiated leucine. In radioautographs, the localization and the relative label concentration were comparatively estimated for the different components of mitochondria-rich fibres, in particular of red fibres, from the tibialis anterior muscle and of mitochondria-poor fibres from the oesophageal muscle. As early as 2 min after injection, radioactivity was detected over the nucleus, the polysome-rich sarcoplasm, the A and I bands, the Z lines, and the mitochondria in the two fibre types. Label localization did not change with time. The relative label concentration increased similarly in the polysome-rich sarcoplasm and the A and I bands of both fibre types within 30 min after injection, a confirmation that biosynthesis of myofibrillar proteins takes place rapidly. In each case, concentration was higher in the Z lines than in the I bands, and higher in the I bands than in the A bands, thus showing “in vivo” that the rates of synthesis of sarcomere protein components are not uniform. However, the relative label concentration was found to be higher in the Z lines of mitochondria-poor fibres than of mitochondria-rich fibres: this suggests that a higher synthetic rate of Z line protein, and probably of α actinin, is characteristic of the first type. Inversely, the concentration was higher in the mitochondria of mitochondria-rich fibres. This lead to the belief that high rate of protein synthesis in these organelles may account for the high rate of label incorporation into this type of fibre.
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  • 62
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    Cell & tissue research 193 (1978), S. 297-313 
    ISSN: 1432-0878
    Keywords: Pars intermedia ; Peroxidase ; Ultrastructure ; Extravascular space ; Stellate cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To study the transport of protein from the blood into and throughout the sparsely vascularized pars intermedia of anurans, the electrondense tracer, horseradish peroxidase (HRP) was injected into the vascular system of adult frogs. A strong reaction product was localized in small vesicles in the cytoplasm of that portion of the stellate cells immediately beneath the vascular spaces. Also, within two minutes after an injection of HRP, which was given during a period of one minute, the reaction product was seen in the extracellular spaces between the stellate and/or MSH secretory cells throughout the gland. Additionally, it appeared that HRP was pinocytosed by the stellate cell processes in the interior of the pars intermedia. Since frogs adapted to different backgrounds were perfused with HRP for a variety of time periods, from 3 to 90 min, it was thought that it would be possible to trace the pathway of the HRP-filled vesicles as they moved through the stellate cells. There did not appear to be a migration of these vesicles within the cells. Because of the electron density of the HRP, the tortuous extensions from the perivascular spaces of the capillary plexus intermedius were obvious as they ramified into the pars intermedia and pars nervosa. In the frogs not injected with HRP, it was possible to observe the substructure of these ramifications which paralleled the stellate cells and formed enlargements at the convergence of the stellate cell processes and sometimes the nerve processes. An extravascular, many-branched transport system that penetrates the parenchyma is discussed in addition to the possible transfer role of the stellate cells.
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  • 63
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    Cell & tissue research 193 (1978), S. 337-351 
    ISSN: 1432-0878
    Keywords: Egg shells ; Anostraca ; Alveolar meshwork ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tertiary shell of the eggs of anostracan crustaceans consists of two layers, an outer cortex and an inner alveolar layer. Scanning electron microscope studies show that, in most species, these layers are separated by a subcortical space which intercommunicates with spaces in the cortex and with the meshwork of the alveolar layer. No evidence was found for direct communication between pores on the surface of Branchipus stagnalis eggs and the subcortical space. No surface pores were found in the eggs of Branchinecta packardi, Chirocephalus diaphanus, Anemia salina, nor in eggs of the notostracan Triops cancriformis. Similarities in structure and possible functions of the egg shells of anostracan crustaceans and certain insects are discussed in relation to similarities in certain features of their environments.
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  • 64
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    Cell & tissue research 193 (1978), S. 323-336 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Gerbil ; Pinealocytes ; Concretions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy was employed in a study of the pineal gland of the Mongolian gerbil (Meriones unguiculatus). It was determined that the gerbil pineal gland contains pinealocytes and glial cells with the pinealocytes being the predominant cell type. The pinealocytes contain numerous organelles traditionally considered as being either synthetic or secretory in function such as an extensive Golgi region, smooth (SER) and rough (RER) endoplasmic reticulum, secretory vesicles and microtubules. Other cytoplasmic components are also present in the pinealocytes (synaptic ribbons, subsurface cisternae) for which no function has been assigned. Dense-cored vesicles are rare. Vacuolated pinealocytes are present and appear to be intimately associated with the formation of the pineal concertions. Evidence presented supports the proposal that the concretions form within the vacuoles. Once the concretions reach an enlarged state, the vacuolated pinealocytes break down and the concretions are thus extruded into the extracellular space where they apparently continue to increase in size. The morphology of the glial cells was interpreted as indicative of a high synthetic activity. The glial cells contain predominantly the rough variety of endoplasmic reticulum and form an expansion around the wide perivascular area.
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  • 65
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    Cell & tissue research 194 (1978), S. 125-130 
    ISSN: 1432-0878
    Keywords: Sarcotubular development ; Chick embryo ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dilations of the sarcotubular system and misaligned myofilaments have been reported as early indicators of muscular dystrophy in skeletal muscle. Since the developing tubular component is believed instrumental in initial myofilament alignment during myogenesis, tubular development is evaluated using normal and dystrophic chick embryo skeletal muscle and cultures of normal and dystrophic embryonic pectoral muscle incubated in the presence of horse spleen ferritin. Comparisons of the findings show that periodic tubules are absent from dystrophic somitic muscle and that invaginating tubules from the sarcolemma are found in fewer, randomly located areas of dystrophic pectoral muscle cells. The results indicate that the tubular component is not involved in the bizarre vesiculations seen in mature dystrophic muscle, however, the malalignment of dystrophic myofilaments is probably the result of the poorer development of the T system in this muscle.
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  • 66
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    Keywords: Pancreas ; Gut ; Pancreatic polypeptide (PP) cells ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic polypeptide (PP) cells in the pancreas and gut of chickens were studied by immunocytochemistry. In the pancreas PP cells were numerous and disseminated in the exocrine parenchyma. In this location they were first seen at the 9th day of incubation, i.e. several days after the appearance of glucagon, insulin and somatostatin cells. Very large numbers of these cells occurred from about the 14th day until shortly after hatching when the PP cell frequency was somewhat reduced. At the 17th day of incubation PP cells appeared in the duodenum. Subsequently the number of PP cells in the duodenum increased, and PP cells began to appear also in the jejunum-ileum (19th day) and in the proventriculus and colon (21st day). At hatching and a few days thereafter, PP cells were relatively numerous in the small intestines but much less frequent in the proventriculus and colon. One week after hatching PP cells had disappeared from the colon but remained in the proventriculus and small intestines. Ultrastructurally the PP cell was clearly distinguishable from the insulin, glucagon and somatostatin cells. It was characterized by the presence of spherical cytoplasmic granules which were membrane-bound and moderately electron dense. Areas of firm adhesion between PP cells and acinar cells in the form of desmosomes and possibly also gap junctions were observed.
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  • 67
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    Cell & tissue research 194 (1978), S. 405-418 
    ISSN: 1432-0878
    Keywords: Hyla arborea ; Reflectance spectrophotometry ; Ultrastructure ; Color change ; Chromatophores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die strukturellen Veränderungen der Chromatophoren beim Farbwechsel von Hyla arborea wurden mit Hilfe von Elektronenmikroskopie und Reflexions-Mikrospektrophotometrie untersucht. Während des Wechsels von einer hellgrünen zu einer dunkelgrünen Farbe breiten sich die Melanosomen aus, bis sie schließlich die Iridophoren und teilweise auch die Xanthophoren umhüllen; die becherförmigen Iridophoren werden zylinderoder kegelförmig. Gleichzeitig verändern die Purintäfelchen ihre Orientierung parallel zur Oberseite der Zelle und sind unregelmäßiger ausgerichtet; die linsenförmigen Xanthophoren werden plattenförmig. Der Wechsel von grüner zu grauer Färbung scheint stets über Schwarzgrün oder Dunkelolivgrün zu gehen. Die Xanthophoren keilen sich dann zwischen die Iridophoren ein und liegen in der grauen Haut oft unterhalb der letzteren; die Pterinosomen sammeln sich in der Peripherie der Zelle, während sich die Carotenoidvesikel um den Kern herum häufen. Die Iridophoren in der grauen Haut sind fast kugelförmig mit Purintäfelchen in konzentrischen Schichten. Eine hellgraue Färbung geht aus einer dunkelgrauen durch Aggregation der Melanosomen hervor. Die Chromatophorenwerte (“chromatophore values”), die Nielsen und Dyck (1978) für Hyla cinerea definierten, sind auch für Hyla arborea verwendbar; die Annahmen, die diesen Werten zugrunde liegen, werden jetzt ultrastrukturell gestützt.
    Notes: Summary The structural changes in the chromatophores of Hyla arborea related to changes in skin color were studied by electron microscopy and reflectance microspectrophotometry. During a change from a light to a darker green color, the melanosomes of the melanophores disperse and finally surround the iridophores and partly the xanthophores. The iridophores change from cup-shape to a cylindrical or conical shape with a simultaneous change in the orientation of the platelets from being parallel to the upper surface of the iridophores to being more irregular. The xanthophores change from lens-shape to plate-shape. The color change from green to grey seems always to go through a transitional black-green or dark olive green to dark grey. During this change the xanthophores migrate down between the iridophores, and in grey skins they are sometimes found beneath them. The pterinosomes gather in the periphery of the cell, while the carotenoid vesicles aggregate around the nucleus. The iridophores in grey skin are almost ball-shaped with concentric layers of platelets. A lighter grey color arises from a darker grey by an aggregation of melanosomes. The chromatophore values previously defined for Hyla cinerea are applicable in Hyla arborea, and the ultrastructural studies support the assumptions previously made to explain these values.
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  • 68
    ISSN: 1432-0878
    Keywords: Tegmental reticular nucleus (Bechterew) ; Serotonin neurons ; Reticular formation ; Ultrastructure ; Synaptic organization
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    Topics: Biology , Medicine
    Notes: Summary The organization of the tegmental reticular nucleus of von Bechterew (TRN) has been analyzed in Nissl and Golgi material, by fluorescence histochemistry, and by electron microscopy. In the albino rat, the TRN situated in the ventral paramedian midbrain and pontine reticular formation, contains two principal types of neurons. The first is a population of large multipolar neurons (40–80 μm diameter) with abundant Nissl substance and 4–7 smooth dendrites which may extend up to 500 μm in length. The second is medium-sized fusiform neurons (14–40 μm diameter) with less Nissl substance and two primary dendrites that originate from each pole of the soma and have a more closely ramifying dendritic field. Fluorescence histochemistry demonstrates that serotonin neurons constitute one component of the medium-sized neuron group. A third neuronal type, infrequently encountered at the outer margins of the nucleus, corresponds to the large, multipolar isodendritic neurons (soma diameter 40–80 μm) of the pontine reticular formation. Ultrastructural analysis of the TRN also demonstrates large and medium sized neurons which are present, together with numerous large dendritic trunks, between bundles of myelinated axons traversing the TRN in both rostrocaudal and transverse planes. This distinctive arrangement produces the appearance of “gray islands” between myelinated axon bundles. Within these areas, abundant synaptic terminals occupy a large proportion of the available terminal space on the surface of dendrites and perikarya, particularly of the large type of neuron. Two types of synaptic terminals are encountered; S-type synapses contain lucent spherical synaptic vesicles and F-type synapses contain flattened lucent vesicles. In addition there is a small number of synaptic terminals with scattered 100–120 nm diameter dense core vesicles in a population of smaller pleomorphic vesicles. These account for no more than 10% of the synaptic terminal population.
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  • 69
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    Cell & tissue research 194 (1978), S. 533-545 
    ISSN: 1432-0878
    Keywords: Corpus allatum ; Insects ; Ovariectomy ; Ultrastructure ; Cytophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the corpora allata of 29 Leucophaea ovariectomized in the nymphal stage and maintained up to an adult age of 28 months was examined. In general, the subcellular morphology of these glands has much in common with that of normal female controls examined at the height of their activity. In addition, the most “typical”of the gonadectomy cases show certain distinctive features that are either absent or much less prominent in unoperated controls. Of primary interest is the striking abundance of smooth surfaced endoplasmic reticulum observed in many but not all of the castrates. Since this organelle is implicated in the biosynthesis of juvenile hormone, the factor normally responsible for yolk deposition, its increase, together with certain additional ultrastructural features, is indicative of an exceptionally high rate of hormone production. An explanation for the putative hyperactivity displayed to various degrees by the experimental animals may well be the constancy of the demand on their corpora allata, since removal of the ovaries abolishes the afferent signals in response to which, in the intact female, the brain turns off these glands during the long periods of gestation. That the synthetic effort may eventually level off, even in the absence of regular inhibitory stimuli, is suggested by the corpora allata of those castrates, the ultrastructure of which reflects moderate activity or possibly further regression
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  • 70
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    Cell & tissue research 195 (1978), S. 59-79 
    ISSN: 1432-0878
    Keywords: Compound eyes ; Arthropod vision ; Deep-sea crustaceans ; Ultrastructure ; Thysanopoda tricuspidata (Euphausiacea)
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    Topics: Biology , Medicine
    Notes: Summary The compound eyes of the mesopelagic euphausiid Thysanopoda tricuspidata were investigated by light-, scanning-, and transmission electron microscopy. The eyes are spherical and have a diameter that corresponds to 1/6 of the carapace length. The hexagonal facets have strongly curved outer surfaces. Although there are four crystalline cone cells, only two participate in the formation of the cone, which is 90–120 μm long and appears to have a radial gradient of refractive index. The clear zone, separating dioptric structures and retinula, is only 90–120 μm wide. In it lie the very large oval nuclei of the seven retinula cells. Directly in front of the 70 μm long and 15 μm thick rhabdom a lens-like structure of 12 μm diameter is developed. This structure, known in only a very few arthropods, seems to be present in all species of Euphausiacea studied to date. It is believed that the rhabdom lens improves near-field vision and absolute light sensitivity. Rod-shaped pigment grains and mitochondria of the tubular type are found in the plasma of retinula cells. The position of the proximal screening pigment as well as the microvillar organization in the rhadbdom are indicative of light-adapted material. The orthogonal alignment of rhabdovilli suggests polarization sensitivity. Behind each rhabdom there is a cup-shaped homogeneous structure of unknown, but possibly optical function. Finally, the structure and the function of the euphysiid eye are reviewed and the functional implications of individual components are discussed.
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  • 71
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    Cell & tissue research 195 (1978), S. 111-122 
    ISSN: 1432-0878
    Keywords: Epidermis ; Skin ; Ultrastructure ; Rana ; Metamorphosis
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    Topics: Biology , Medicine
    Notes: Summary The organisation of the ventral epidermis organisation was followed throughout ontogenesis in Rana ridibunda. Epidermis of tadpoles with 2–3 limbs was organised into two layers: a stratum germinativum consisting of elongated columnar cells, and an outer stratum corneum consisting of two types of cuboid cells. Two types of cells can be distinguished; they are a light (clear) cell and a dark (dense) cell. In the 4-legged tadpoles the stratum corneum cells start to flatten and a replacement layer appeared underneath. A well-defined stratum germinativum is found and within it, epidermal glands. Moulting took place for the first time in tadpoles just before metamorphosis, and a well-organised stratum granulosum was formed still containing the two main types of epidermal glands. The flask cells appear in the juveniles for the first time, greatly increasing in numbers in the adult epidermis.
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  • 72
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    Cell & tissue research 195 (1978), S. 123-144 
    ISSN: 1432-0878
    Keywords: Pigment cells, extracutaneous ; Melanocytes ; Guanocytes ; Ultrastructure ; Plaice (Teleost)
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The extracutaneous pigment cell system of the plaice (Pleuronectes platessa L.) was examined by light and electron microscopy in selected regions, including two cutaneous regions for comparison. The extracutaneous pigmentation consists of guanocytes and melanocytes with differing distributions within the body. The eyeless side lacks melanocytes. The pigment cells are differentiated as very flat elements with long processes. They display an affinity for loose connective tissue at boundary layers such as the peritoneal epithelium, organ capsules or blood vessels, to which they are parallelly arranged at a very constant distance. In some locations guanocytes are intimately associated with melanocytes forming “reduced chromatophore units”. Extracutaneous pigment cells are poor in mitochondria, endoplasmic reticulum, microfilaments, caveolae intracellulares, ribosomes and glycogen granules, all of which are more abundant in cutaneous pigment cells and pigment cells of the eye. In extracutaneous guanocytes the crystals are loosely arranged parallel to the cell surface, in cutaneous guanocytes perpendicular. Cells with rod-like vesicular cisternae are described as “guanoblasts”. No single pigment cell was found exhibiting different types of pigment granules. The varying colors of extracutaneous pigmentation arise from varying combinations of guanocytes and melanocytes in addition to the color of the tissue itself.
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  • 73
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    Cell & tissue research 195 (1978), S. 309-316 
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    Keywords: Ultimobranchial gland ; Birds ; Follicular cell types ; Ultrastructure ; Secretion
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    Topics: Biology , Medicine
    Notes: Summary The ultimobranchial gland of the laying chicken consists of groups of C cells interspersed among a collection of intercommunicating follicles and ducts of variable size and shape. The epithelium lining this system ranges from squamous to columnar and includes stratified squamous and pseudostratified columnar elements. Four cell types are distinguished in this epithelium: F, mucous, C, and basal cells. F cells show microvilli and microfilaments. Pinocytotic activity and images of fusion of coated vesicles with the plasma membrane are evident. The rough-surfaced endoplasmic reticulum (RER) and the Golgi complex are moderately developed. Dense bodies are encountered apically in some cells. Mucous cells possess microvilli and secretory material in the typical form of partially fused droplets. C cells contain secretory granules and are invariably separated from the follicular lumen by other cell types. The smaller, pyramidal basal cells contain filaments, RER, small Golgi complexes, free ribosomes and hemidesmosomes. The lumina contain flocculent or granular material, cellular debris and desquamated cells. Morphological evidence demonstrates that features of the pharyngeal epithelium are retained and that the majority of the cell types, with the exception of C cells, are presumably nonendocrine.
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  • 74
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    Cell & tissue research 195 (1978), S. 461-469 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Cold ; Ultrastructure ; Mouse
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    Notes: Summary Ultrastructural changes in pinealocytes were investigated qualitatively and quantitatively in mice exposed to low temperatures at 0° C or 5° C for 30 or 60 min. A quantitative estimation of the granulated vesicles of about 100 nm diameter in pinealocytes demonstrated that the number of these vesicles per pinealocyte in mice exposed to cold at 0° C or 5° C increased remarkably as compared with that of the controls. This finding indicates that cold stimuli may activate the formation of the granulated vesicles in pinealocytes. In mice exposed to cold at 0° C for 60 min, granulated vesicles were often found in groups close to the plasma membrane of the pinealocyte cell bodies or processes, indicating the release of the vesicle content into the extracellular spaces. Additionally, the pinealocytes of the mice exposed to cold at 0° C for 60 min were characterized by the frequent occurrence of lysosome-like bodies and filaments. The development of these structures in response to severe cold may represent a depressed functional state of pinealocytes.
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  • 75
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    Cell & tissue research 195 (1978), S. 535-545 
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    Keywords: Pineal organ ; Troglobytic fish, Typhlichthyes subterraneous ; Ultrastructure
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    Notes: Summary The pineal organ of the blind, cave-dwelling fish, Typhlichthyes subterraneous, was examined with both light and electron microscopes. Like the eyes, the pineal in this troglobytic species was found to be regressed. Two cell types, photoreceptor and supportive cells, were described in the pineal epithelium. Although ganglion cells were not identified, small, unmyelinated nerve fibers were present. The photoreceptor cells had degenerated outer segments. Accordingly, it was suggested that the pineal in this species is not likely to function in photoreception. However, the presence of well developed Golgi bodies, clear and dense-cored vesicles, variable amounts of rough endoplasmic reticulum and glycogen particles indicated that both cell types are metabolically active and may play a role in secretion.
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  • 76
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    Cell & tissue research 195 (1978), S. 547-556 
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    Keywords: Pineal organ, rat ; Ultrastructure ; Organ culture ; Gonadotropic hormones ; LH-RH
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    Notes: Summary The influence of gonadotropic hormones on the ultrastructure of rat pinealocytes in short-term organ culture was studied. Human chorionic gonadotropin (HCG), as well as pregnant mare serum gonadotropin (PMSG), caused a marked activation of pinealocytes. An hypothesis is discussed implying the presence of a feedback mechanism between the pineal organ and the hypothalamo-hypophysial system.
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  • 77
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    Cell & tissue research 190 (1978), S. 27-45 
    ISSN: 1432-0878
    Keywords: Kidney tubules (proximal) ; Teleost (Pleuronectes platessa) ; Lanthanum ; Microinjections ; Ultrastructure
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    Notes: Summary A new method combining electron microscopy with microdissection was used to study the segmental variation along the tubule of a marine flounder. Two different nephron types were present. One type had long tubules with the glomeruli located close to the kidney surface. The other type had shorter and more coiled tubules with the glomeruli located close to the terminal end of the same nephron. Five different segments were present: (1) neck segment, (2) first proximal segment, (3) second proximal segment, (4) third proximal segment, and (5) collecting tubule. The third proximal segment was not present in all tubules. An extensive system of infoldings from the plasma membrane was present in all segments, except the neck segment and the collecting tubule. Tight junctions impermeable to lanthanum were present in all segments. The collecting duct cells also had extensive infoldings from the plasma membrane and tight junctions impermeable to lanthanum were also present here.
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  • 78
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    Cell & tissue research 191 (1978), S. 267-286 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Supraoptic nucleus ; Paraventricular nucleus ; Ultrastructure ; Brattleboro rat
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    Topics: Biology , Medicine
    Notes: Summary The hypothalamo-posthypophysial complex of the homozygous Brattleboro rat is characterized by a hyperactivity of its neurons. The neurosecretory fibers, especially in the neurohypophysis, show numerous signs of autophagy and tubular proliferation of the axoplasmic reticulum. These structural alterations, as well as the nematosomes or nucleolus-like bodies encountered in the perikarya, may be related to the chronic hyperactivity of the neurons. They can be reduced by administration of exogenous vasopressin. The numerous liposomes in the pituicytes are paralleled in the neuronal perikarya by a great number of lysosomes. Small dense core vesicles observed in the neurosecretory endings and perikarya may indicate a secretory product distinct from oxytocin and vasopressin. In the homozygous Brattleboro rat, endings of the aminergic type are more numerous than in the normal rat. With respect to the role they may play in the secretory processes, their increase might be secondary to the vasopressin deficiency.
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  • 79
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    Cell & tissue research 191 (1978), S. 343-356 
    ISSN: 1432-0878
    Keywords: Lung ; Amphibia ; Ultrastructure ; Morphometry
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    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and morphometric investigations were performed on the lung of the European salamander, Salamandra salamandra L. Folds of first and second order are covered with a ciliated epithelium containing goblet cells. The respiratory surface of the lung is lined by a single type of cell which, in amphibians, combines features of type I and type II alveolar cells of the mammalian lung. In the salamander the respiratory and ciliated epithelial cells as well as goblet cells possess electron dense and lucent vesicles in their cytoplasm as well as lamellar bodies. A small amount of surfactant, composed most probably of phospholipids and mucopolysaccharides, was observed covering the entire inner surface of the lung. Morphometric methods were used to determine the dimensions of the perinuclear region of pneumocytes, the thickness of the air-blood barrier and lung wall, and also the diameter of capillaries. The thickness of the respiratory air-blood barrier was found to be considerably higher than that of the corresponding barrier in mammals.
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  • 80
    ISSN: 1432-0878
    Keywords: Programmed cell death ; Motor neurons ; Neuro-glial interaction ; Ultrastructure ; Manduca (Lepidoptera)
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    Topics: Biology , Medicine
    Notes: Summary Ultrastructural aspects of the natural degeneration of a group of six motor neurons in the fourth abdominal ganglion of Manduca sexta are described. These motor neurons innervate intersegmental muscles that degenerate and disappear immediately after adult eclosion. The first detectable changes in the cell bodies appear 12 h after eclosion and include disruption of the endoplasmic reticulum and an increase in the size and number of lamellar bodies. At 32 h the nuclear membranes rupture, and the membranous and granular cytoorganelles segregate in different parts of the cell. At that stage the surrounding glial cells participate in the digestion of material from the degenerating neurons. From 72 h onward the remaining neuronal structures become disrupted, and are finally transformed into a single, large lamellar body (residual body) within the glial profile. The degeneration pattern differs significantly from that of embryonic vertebrate neurons.
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  • 81
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    Cell & tissue research 191 (1978), S. 305-315 
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    Keywords: Innervation ; Pancreatic islets ; Teleosts ; Axonal iontophoresis ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary The innervation of the pancreatic islets of a teleost fish, Gillichthys mirabilis, was investigated with various techniques including axonal iontophoresis of cobalt, light microscopy, and electron microscopy. Two types of postganglionic neurons, the splanchnic and the vagus, innervate the islet parenchyma. The splanchnic fibers originate from the single coeliac ganglion, situated near the third spinal nerve on the right side, and pass caudally to the islet. Postganglionic vagal fibers reaching the islets arise from ganglion cells located at irregular intervals along the vagus nerve. Iontophoresis of cobaltous chloride revealed that both types of nerves send large numbers of fibers to the islet cells. Electron microscopy showed that the granules of the vagal fibers are polymorphic, large (130 mm diameter) and markedly electron dense, whereas the splanchnic granules are smaller (100 nm diameter) and less electron dense than those of the vagus. These granules do not correspond to those seen in postganglionic autonomic neurons of other vertebrates. Rather, they are more like classical neurosecretory granules. Although their chemical nature is unknown, the extent of islet innervation suggests that it must play an important regulatory role.
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  • 82
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    Keywords: Leydig cells ; Seminal vesicle ; Pineal gland ; Golden hamster ; Ultrastructure
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    Notes: Summary Fine structural changes of testicular interstitial cells of Leydig and secretory cells of seminal vesicles were studied in golden hamsters under different functional states of the pineal gland. Experiments were performed in the reproductive season (summer months). In the hamsters blinded for 8 weeks the testes and the seminal vesicles were markedly atrophic, and the Leydig cells and the secretory cells of seminal vesicles were extremely involuted. By contrast, both types of cells in the pinealectomized or superior cervical ganglionectomized hamsters exhibited cytological features suggestive of an enhanced secretory activity. This study shows that functional activity of Leydig cells as well as secretory cells of seminal vesicles in the hamster may be depressed or augmented by stimulating or inhibiting the pineal antigonadal function, respectively, without performing hypophysectomy or hormonal administration.
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  • 83
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    Cell & tissue research 191 (1978), S. 389-404 
    ISSN: 1432-0878
    Keywords: Subfornical organ ; Japanese quail, Coturnix coturnix japonica ; Ultrastructure ; Scanning electron microscopy
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    Notes: Summary The surface ultrastructure of the subfornical organ (SFO) was investigated in the Japanese quail. The SFO consists of a body and a stalk. The body of the SFO can be divided into rostral and caudal parts. On the rostral part, each ependymal cell possesses a short central solitary cilium; clustered cilia are also occasionally seen. Microvilli are abundant. On the caudal part, cells with a solitary cilium are fewer in number, and clustered cilia are rarely found. Microvilli are not as abundant as on the rostral part. In addition, large bulbous protrusions, tufts of small protrusions, deep funnel-shaped hollows, small pinocytotic invaginations and possible cerebrospinal fluid-contacting axons are sporadically observed on the surface of various regions of the body. Each ependymal cell of the stalk has a wide apical surface. A central solitary cilium, microvilli and other structures are observed more rarely on the stalk than on the body, while clustered cilia are not seen on the stalk. These structures are compared with those of the mammalian SFO and further discussed in relation to the possible dipsogenic receptor function for angiotensin II.
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  • 84
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    Cell & tissue research 192 (1978), S. 451-460 
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    Keywords: Endometrium ; Baboon ; Oral contraceptive ; Histochemistry ; Ultrastructure
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    Topics: Biology , Medicine
    Notes: Summary Endometrium from a group of baboons treated with the oral contraceptive, Enovid E, was studied histologically, histochemically and ultrastructurally, and compared to endometrium from normally cycling animals. All endometria were obtained by transcervical uterine biopsy between 10 and 14 days of the treatment cycle or the normal menstrual cycle. Histologically, no discernible differences between the control and experimental endometria were apparent. While observable differences were not evident between the endometrial alkaline phosphatase and succinate dehydrogenase activities of control and experimental animals, there was an increased acid phosphatase activity in the Enovid E-treated baboon endometrium. Ultra-structurally, the glandular cells of treated animals appeared to be more physiologically advanced than did those from the control endometria. These advances were evident from the prominent Golgi complex, increased development of the endoplasmic reticulum and increases in the size, number and complexity of mitochondria. The functional correlates of these morphological and histochemical observations are discussed and compared to human endometrial studies.
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  • 85
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    Cell & tissue research 192 (1978), S. 363-379 
    ISSN: 1432-0878
    Keywords: Adrenal glands ; Birds ; Ultrastructure ; Corticosterone ; Zonation
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    Notes: Summary Although interrenal tissue from the intact duck does not show a clear zonation when examined by light microscopy, the tissue does develop a well defined zonation following exposure to high and low levels of corticotropic stimulation. Under these conditions clear ultrastructural differences are seen between cells of the subcapsular zone (SCZ) and the inner zone (IZ). Based on these observations, the ultrastructure of tissue from intact birds was examined retrospectively and in addition, cell sizes and the relative volumes and areas of intracellular components were measured morphometrically. These analyses reveal morphological and quantitative differences between cells from the IZ and the SCZ. Cells of the IZ have small rounded nuclei, extensive smooth endoplasmic reticulum (SER) and mitochondria with tubular cristae, whereas cells from the SCZ contain pleomorphic nuclei, less SER and mitochondria with shelf-like cristae. The mean cell volume in the IZ is significantly less than that in the SCZ. In the SCZ cells the volume densities (volume per unit volume cytoplasm) of mitochondria and lipid droplets and the surface densities (area per unit volume cytoplasm) of the outer mitochondrial membranes are significantly greater than those in IZ cells. Conversely, in the cells of the IZ the volume densities of the nuclei and dense bodies and the surface density of the SER are greater than the corresponding values estimated for the cells of the SCZ. Although the mitochondria comprise a smaller fraction of the mean volume of IZ cells than SCZ cells, the total surface area of the cristae is approximately the same in the cells of both zones.
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    Cell & tissue research 192 (1978), S. 503-512 
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    Keywords: Juxtaglomerular apparatus ; Monkey (Cebus apella) ; Ultrastructure ; Morphometry
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    Notes: Summary The authors describe the ultrastructure of the juxtaglomerular apparatus in five adult male Cebus apella monkeys and communicate morphometric data of the macula densa. In comparison with several species of rodents examined before, the macula cells of the monkey contain many more mitochondria and possess a particularly thick basal membrane. The relative volume of the nuclei is slightly smaller than in rodents. The Goormaghtigh cells of the monkey resemble those of the other animals investigated. The epithelioid (or juxtaglomerular) cells do not contain secretory granules. This observation reminds one of the behavior of the epithelioid cells of guinea pigs.
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    Cell & tissue research 193 (1978), S. 35-40 
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    Keywords: Planarian ; Scanning electron microscopy ; Epidermis ; Sense organs ; Ultrastructure
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    Notes: Summary The epidermis of D. tigrina was examined using the scanning electron microscope. Both dorsal and ventral surfaces are extremely irregular in contour, as well as being permeated by large numbers of pores. Cilia are restricted to the ventral surface, the auricles and that part of the dorsum adjacent to the auricles. Club-shaped receptors, as well as cilia, were seen in the auricles. The epidermis anteriad to the eyespots is indistinguishable from that covering the remainder of the dorsal surface. Light rays could not enter the eyespot through this rough epidermal surface without becoming diffracted in an irregular fashion. It was therefore concluded that visual image perception is not a function of the planarian eyespot.
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  • 88
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    Cell & tissue research 193 (1978), S. 125-137 
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    Keywords: Insect-reproduction ; Ovary ; Oviduct ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The lateral oviduct and calyx of nulliparous Aedes aegypti on a sucrose diet are both flattened sacs, lacking a well defined lumen. Both are formed of an inner epithelial and an outer muscular layer, each one cell thick. The lateral oviduct is surrounded by a circular muscle sheath which is continuous with the ovarian sheath. Each ovariolar sheath is continuous with the outer layer of the calyx. The structure of both the lateral oviduct and the calyx is greatly modified after the initial blood meal. A distinct lumen develops; there is an extensive development of the outer muscular layers, and the inner epithelial layers become invaginated forming deep crypts lined with extensive microvilli. The follicular stem, which joins the primary follicle to the calyx in each ovariole, is not hollow and does not mark the opening into the calyx through which the mature egg can pass. The eggs gain access to the oviductal system after the calyx extends around the follicular epithelium of the primary follicle, when breaks appear in the calyx wall opposed to the follicular epithelium, until the mature eggs, eventually lie in a highly distended thin-walled sac of calyx from which they have direct and easy access to the lateral oviduct. After oviposition, this sac contracts to occupy once more a compact axial position in the ovary. Remnants of the follicular epithelium, containing many lysosomes are attached to the calyx at this time.
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  • 89
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    Cell & tissue research 193 (1978), S. 433-442 
    ISSN: 1432-0878
    Keywords: Hypophysectomy ; Interstitial gland ; Ultrastructure ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the interstitial gland of the ovary was studied in hypophysectomized rats and in hypophysectomized rats after denervation of the ovary or stimulation of the ovarian plexus. Hypophysectomized rats were used to eliminate gonadotropic influences on interstitial cells. In hypophysectomized rats, there was a large amount of intercellular space and cells had irregularly shaped nuclei and a large nuclear-cytoplasmic ratio. Prominent cytoplasmic features included small mitochondria with an electron-dense matrix, rough and smooth endoplasmic reticulum, polysomes and large osmiophilic lipid droplets. Interstitial cells from stimulated ovaries had reduced intercellular space and a reduced nuclear-cytoplasmic ratio. Mitochondria had tubular cristae; smooth endoplasmic reticulum-surrounded lipid droplets, and large polysomes were present. After section of the ovarian plexus, intercellular space was increased and filopodia were numerous. Cytoplasmic features included mitochondria with a dense matrix and indistinct cristae, large electronlucent lipid droplets, and variously sized multivesicular structures. These observations suggest that stimulation of the ovarian plexus in hypophysectomized rats causes regressed cells to assume the fine structural features of active steroidogenic cells. In contrast, interruption of the ovarian nerve supply causes a qualitative and quantitative increase in ultrastructural features characteristic of regressed steroidogenic cells. These responses of interstitial gland cells to denervation and stimulation provide morphological evidence for a functional role for the adrenergic nerves to this ovarian compartment.
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  • 90
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    Cell & tissue research 193 (1978), S. 463-471 
    ISSN: 1432-0878
    Keywords: Macrophages ; Ultrastructure ; Testicular involution ; Swan, Cygnus olor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the swan, Cygnus olor, spermatogenesis shows a pronounced seasonal cycle. During the long involution phase a transient invasion of macrophages into the seminiferous tubules regularly takes place at the height of regression prior to total rest. These macrophages are involved in the additional disposal of supernumerary and degenerating premature germ cells, at a time when the Sertoli cells are already filled with phagolysosomes.
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  • 91
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    Cell & tissue research 193 (1978), S. 525-532 
    ISSN: 1432-0878
    Keywords: Intranuclear inclusions ; Neurons ; Development ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of intranuclear rodlets, microtubules, fibrillar lattices and membranous inclusions found in the developing cuneate nuclei of rats is described. Rodlets, ranging in diameter from 96–312 nm and in length from 1–2 μm, are made up of tightly packed straight filaments measuring 5–8 nm in diameter. Microtubules with a diameter of 26 nm are clustered together. Fibrillar lattices are made up of fibrils with a diameter of 9 nm arranged in layers or sets. Two to nine sets make up a lattice, with a maximum width of 68 nm, in which the adjacent sets are arranged at an angle to each other. Rodlets and fibrillar lattices occur in 6.8% of the neurons. Membranous inclusions, reported here for the first time in normal neurons, are of 2 types: small vesicles of 0.1–0.6 μm and large vacuoles measuring 1–2 μm. Both types are bounded by either a single or a double membrane and generally have an electron lucent content. Membranous inclusions occur in 25.3 % of the neurons. Changes in the frequency of occurrence of the various intranuclear inclusions in the course of postnatal development are also reported.
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  • 92
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    Cell & tissue research 194 (1978), S. 17-35 
    ISSN: 1432-0878
    Keywords: Synapses ; Optic nerve ; Suprachiasmatic nucleus ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synapses of optic nerve afferents (optic synapses) in the rat suprachiasmatic nucleus (SCN) have been identified ultrastructurally. They are easily distinguished from other types of synapses. The optic boutons are characterized by the presence of large mitochondria with a swollen electron lucent matrix and an interconnected tubular system formed by their inner membrane. Other, more variable features include: 1) a scattered pattern of synaptic vesicles which are found throughout the entire presynaptic element with relatively little accumulation near the active zones; 2) the occurrence of dense core vesicles and glycogen granules; 3) the active zones, the majority of which is Gray-type I, but a minority can obviously be classified as Gray's type II; 4) the innervation of smaller peripheral dendrites and dendritic spines. Boutons of this kind are exclusively filled with anterogradely transported horseradish peroxidase injected into both eyes. Very few neuronal elements containing the typical mitochondria have been observed in the SCN on the 6th day post partum, increasingly more on the 9th and 12th day, but considerably higher numbers after opening of the eyes on the 17th and the following days. The location of normal and degenerating optic boutons was examined light- and electron microscopically. In the rostral third of the SCN there are relatively few optic synapses which are found close to the optic chiasma. In the middle portion of the SCN optic synapses increase in number; they are found not only in the ventral part of the nucleus but also in lateral regions. This becomes particularly obvious in the caudal third of the SCN.
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  • 93
    ISSN: 1432-0878
    Keywords: Tubule aggregations ; Granular endoplasmic reticulum ; Gastropoda ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Aggregations of cylindriform tubules closely packed in a hexagonal arrangement and associated with the rough-surfaced endoplasmic reticulum (RER) are described in cells of the digestive gland of a sacoglossan gastropod. Each tubule is approximately 61 nm in outer diameter and the central lumen is lined with a layer of finely granular material. The tubule wall is composed of approximately 22 dense subunits. Adjacent tubules are associated with a pair of indistinct granules. Membranes of the RER frequently join the aggregations. The lumen of a tubule may be continuous either with the intracisternal space of the RER or with the cytoplasmic matrix of the cell. It is suggested that the aggregations of tubules are elaborations of the endoplasmic reticulum.
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  • 94
    ISSN: 1432-0878
    Keywords: Campaniform sensilla ; Mechanoreceptors ; Ultrastructure ; Compound eye ; Cricket
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the campaniform sensilla of the cricket eye was investigated by light and electron microscopy. Each sensillum is innervated by a single bipolar neuron. Its axon extends through the retina into a side-branch of the nervus tegumentarius. The dendrite extends through a cuticular channel to the surface of the cornea. The distal part of the dendrite, the sensory process, contains a tubular body and is attached to a cuticular cap which is obliquely inserted into the exocuticle between the corneal lenslets. Some particular structural features as well as the function of the campaniform sensillum of the cricket eye are discussed.
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