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  • 1975-1979  (1,509)
  • Engineering General  (946)
  • Ultrastructure  (563)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 185 (1979), S. 333-346 
    ISSN: 1432-041X
    Keywords: Chick embryo ; Limb bud ; Ultrastructure ; Cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural changes in the wing bud afterapical ectodermal ridge (A.E.R.) removal was studied to re-examine the issue of distal mesenchymal cell death. The A.E.R. of the right wing bud was removed microsurgically from chick embryos of stages 18 to 22 (HH 1951). The wing buds were examined at three hour intervals up to twelve hours after the operation with light, transmission and scanning electron microscopy. The main findings were: (1) Immediate and temporary shrinkage of the mesenchymal extracellular space 100 to 150 μm and chromatin condensation in the cells 50 to 75 μm from the wound. (2) Death of ectodermal and mesenchymal cells in the immediate vicinity of the wound. (3) Formation of a single squamous-like layer of mesenchymal cells to cover the wound. (4) Occasional evidence of cell death in the distal mesenchyme at later times after the operation. The pattern of cell death observed suggests only a traumatic etiology, and gives little evidence for the postulated developmental significance of cell death following A.E.R. removal.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 186 (1979), S. 65-70 
    ISSN: 1432-041X
    Keywords: Sea urchin ; Embryo ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Collagen fibrils with a main period banding of 610 Å and 220 Å in width were observed in the blastocoel of 72-h embryos of the sea urchin,Strongylocentrotus purpuratus. Non-striated fibrils of 50 Å diameter were also observed. The collagen is seen in highest concentration in the vicinity of mesenchyme cells which are richly endowed with endoplasmic reticulum and secretory vesicles. A role for collagen in cell attachment, orientation and spicule formation is discussed.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 155 (1979), S. 95-105 
    ISSN: 1432-0568
    Keywords: Metanephros ; Chicken embryo ; Ultrastructure ; Parathyroid hormone ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A comparative electron microscopical study was conducted on the metanephros from chick embryos differentiated either in shell-less culture or in ovo. Developmental characteristics were very similar in both cases. Up to stage 37 (Hamburger-Hamilton) the metanephros contained large numbers of immature nephrons; their renal corpuscles were crescent-shaped and consisted of an outer layer of flat cells and an inner one of cuboidal cells. In more advanced corpuscles also found at this stage the inner layer had formed numerous rudimentary pedicels and the tunica media of the glomerular arteriole contained juxta-glomerular cells with numerous, small, electron dense granules. In the metanephros from embryos at stage 38 or older, large numbers of nephrons had completed their differentiation; their rounded renal corpuscles had fully differentiated podocytes with thin interdigitating pedicels and the proximal convoluted tubules had numerous apical microvilli, vesicles, vacuoles and tubular invaginations indicating an active process of resorption. These results appear to indicate that both in culture and in ovo-developed embryos, the metanephri start to function around stage 38. In the case of normal embryos this conclusion agrees with previous physiological and biochemical determinations. The injection of 20 USP parathyroid hormone into 16-day old chick embryos produced an increase in the concentration of cyclic AMP in the metanephros. This favours the idea that the regulation of kidney function by the hormone begins during the embryonic period.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 156 (1979), S. 73-88 
    ISSN: 1432-0568
    Keywords: Closure ; Development ; Mammalina embryo ; Neural tube ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fusion of the neural walls in the cephalic part of mouse embryos varying in age from 9 to 20 somites was examined with the electron microscope. In the rhombencephalic region the rim of the neural wall was formed from outside inward by ectodermal surface cells, a row of flattened cells without surface projections and neuroepithelial cells. At the junction of the surface ectoderm and the flat cells were seen large projections containing a cytoplasmic matrix without organelles and previously referred to as “ruffles”. The initial contact between the walls was made by the large cytoplasmic arms and numerous finger-like projections interdigitating with similar projections from the opposite wall. The projections originated from the surface ectoderm and possibly neural crest cells. During further fusion the surface ectoderm cells formed dense membrane specializations, thus establishing a firm contact. The initial contact in the mesencephalon was formed by extensions from the surface ectoderm and was followed by the formation of specialized membrane junctions, as seen between the surface ectoderm in the rhombencephalon. The neuroepithelial cells facing the gap between the neural walls with their apical ends made contact with the cells from the opposing wall by numerous finger-like projections but membrane specializations failed to develop. The closing mechanism in the prosencephalon and anterior neuropore regions differed from the previous areas in that the initial contact was established by the neuroepithelial cells. Only after this contact had been formed did the surface ectoderm cells close the gap. In contrast with the other areas many phagocytosed particles were seen in the prosencephalon and in the region of the anterior neuropore. Many particles from degenerated cells were found inside healthy surrounding cells. Some of these particles contained nuclear material and cytoplasmic organelles.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 155 (1979), S. 333-345 
    ISSN: 1432-0568
    Keywords: Lipofuscin ; Cerebellar cortex ; Ultrastructure ; Senescent rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of autofluorescent, PAS-positive lipofuscin in Purkinje, granule, Golgi epithelial, basket and stellate, microglial and perivascular cells in the cerebellar cortex of senescent rats is described. The membrane-bounded pigment is composed of three elements: 1) electron-lucent homogeneous droplets, 2) a granular matrix and 3) intensely osmiophilic patches. The proportions of these three components vary between cell types and one can grossly differentiate a neuronal and a glial lipofuscin. The lipofuscin granules of stellate and perivscular cells are different from lipofuscin of other cerebellar neurons and glia. It can be concluded from these morphological observations that each cerebellar cell type has its distinct lipofuscin.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 156 (1979), S. 255-267 
    ISSN: 1432-0568
    Keywords: Adenohypophyseal rudiment ; Self-differentiation ; Ultrastructure ; Quail
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Isolated epithelial rudiments of 3–4 days quail embryo adenohypophysis were cultivated in vitro. Differentiation of glandular cells occured when culture conditions allowed the formation of explants characterized by the presence of a fibroblastic sheet and of an epithelial roof surrounding a central cavity. Differentiation did not occur when culture conditions did not allow the fibroblastic sheet to be established or resulted in the absence of a cavity. The importance of the explant structure in differentiation is also indicated by the location of glandular cells. In vitro they differentiate near the cavity derived from Rathke's pouch lumen while in situ they first appear at the periphery of the rudiment, near the basement membrane. The results of this study show that the adenohypophyseal primordium can differentiate without any mesenchymal influence. The observed differentiation seems to be correlated with fibroblast-secreted material, and this hypo-thesis is discussed.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 47 (1979), S. 139-143 
    ISSN: 1432-0533
    Keywords: Perineurium ; Permeability ; Peripheral nerve ; Rat ; Ultrastructure ; Autoradiography ; Albumin ; Peroxidase ; Protein deprivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The permeability properties of the perineurium in sciatic nerves of 12-week-old rats were studied. The penetration of125I-labeled albumin and horseradish peroxidase into the perineurium was investigated electronmicroscopically 10, 30, and 120 min after the local extraneural application of the tracers. The autoradiographic study included age-matched protein-deprived rats. It was concluded that the perineurium acted as a diffusion barrier but also permitted a slow passage of the macromolecules into the endoneurium. The result indicates that this penetration to some extent is due to vesicular transport across the perineurial cells. The significance of these barrier and transport properties of the perineurium is discussed. No obvious differences in perineurial permeability between normal and protein-deprived rats were obtained.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 48 (1979), S. 67-72 
    ISSN: 1432-0533
    Keywords: Pituitary adenoma ; Ultrastructure ; Classitication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of pituitary adenoma secreting more than two hormones is presented. Morphological findings of this tumor have been correlated with biological behavior and with hormonal activity.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 46 (1979), S. 215-220 
    ISSN: 1432-0533
    Keywords: Melanosis of the dentate nucleus ; Glial melanin ; Ultrastructure ; Intrared spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pigment present in melanosis cerebelli where it is deposited in the dentate nucleus and within the cerebellar granular layer is similar to that of S. nigra as judged from the typical infrared absorption bands near wave numbers 3.450 cm−1 and 1.650 cm−1, respectively. According to electron microscopic findings, this type of melanin arises within the astrocytes of the dentate nucleus. The astrocytic melanosomes exhibit a relatively monotonous substructure reaching diameters of 30 μ and more, and they differ in this respect from the triadic neuronal melanosomes of S. nigra that are strongly reminiscent of lipofuscin granules. These differences may be due to additional components of melanosomes, apparently specific of a particular cell type, and they are in turn accounted for by the dissimilar cellular metabolic make-up of nigral cells and astrocytes, respectively. This does not dismiss the possibility, however, that the melanin pigments of either type of melanosomes are the same or closely related to each other as far as their basic chemical composition is concerned. The cause of the melanosis of the dentate nucleus is not known. Possibly involutional tissue changes governed by endocrine factors among others may play an important part.
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  • 10
    ISSN: 1432-0533
    Keywords: Muscular dystrophy ; Becker-type ; Benign X-linked ; Histopathology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle biopsies of two patients originally reported in the Göttingen family by Becker (1962) that formed the basis of separating a benign X-linked muscular dystrophy from the rapidly progressive Duchenne-type X-linked muscular dystrophy, revealed mild pathological changes in the younger patient and more advanced in the older one, consisting of increased spectra of fiber diameters, endomysial fibrosis, angulated fibers, pyknotic nuclear clumps and small groups of atrophic fibers. Essentially, both biopsies showed the same changes, but of different severity, possibly due to the differences in age and muscle biopsy sites. These changes were regarded “myopathic”, but a neurogenic component was suggested. Our observations accord well with those of a larger series (Bradley et al., 1978) where both electromyography and histopathology revealed a mixed “myopathic-neurogenic pattern” in patients with Becker-type dystrophy. Differential diagnostic aspects encompass Duchenne's muscular dystrophy, the other hereditary dystrophies and X-linked proximal spinal muscular atrophies. The precise nature of Becker-type muscular dystrophy requires morphological data on peripheral nerves, spinal roots and spinal cord anterior horn cells as well as sequential biopsy analysis to substantiate the primary site of pathology. However, on the basis of available data, it seems reasonable to suggest that the early changes of degeneration/regeneration which are accompanied by a markedly elevated CPK eventuate in the histopathologic and electromyographic patterns illustrated in these two patients with Beckertype dystrophy.
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  • 11
    ISSN: 1432-0533
    Keywords: Visna ; Slow viral infection ; CSF ; Ultrastructure ; Myelin fractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electron microscopic examination was done on 8 samples of cerebrospinal fluid (CSF) from Icelandic sheep infected by the intracerebral route with visna virus. The specimens were collected 1 month, 2 months, and 4 years after infection. A differential cell count done on low-power electron micrographs showed that the cellular exudate was composed of mononuclear cells mainly macrophages and lymphocytes with a few plasma cells. Macrophages were with one exception more numerous than lymphocytes and an increased proportion of macrophages showed evidence of phagocytosis with time after infection. Reactive lymphocytes were in general more numerous than small lymphocytes. Various stages in the maturation of plasma cells were observed. The cellular composition in the CSF is compatible with the view that visna is an immunopathological process. Myelin figures and fragments of myelinated axons were observed in two specimens indicating an active myelin-breakdown. The possibility that escape of myelin into the CSF may lead to sensitization to myelin antigens and perpetuation of this chronic neurologic affection is discussed. Visna virions could not be demonstrated.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 45 (1979), S. 17-25 
    ISSN: 1432-0533
    Keywords: Brindled mutant mouse ; Male hemizygotes ; Neuronal degeneration ; Ultrastructure ; Giant mitochondria ; Copper deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The brindled mouse (Mobr) is a neurological mutant mouse with clinical and biochemical features closely similar to Kinky hair syndrome (KHS) in humans. Neuronal degeneration in the cerebral cortex and thalamic nuclei was the constant neuropathological lesions in the CNS of the male hemizygotes of this mutant (Yajima and Suzuki, 1978). Ultrastructurally, many cortical neurons contained enlarged mitochondria with prominent tubular or vesicular cristae, which were similar to those described in the Purkinje cells in the human KHS (Ghatak et al., 1972) and in the rat brain with copper deficiency (Prohaska and Wells, 1975). Such mitochondria were observed not only in the degenerating neurons but even in the otherwise normal-appearing cortical neurons, suggesting that the mitochondrial damage possibly related to the deficient activities of the copper containing enzymes (cytochrome oxidase, etc.) preceded the neuronal degeneration. Many mitochondria in the severely degenerated neurons contained numerous electron dense spicules of possible calcium. Although rare, similar morphological alteration of neuronal mitochondria was also noted in the female heterozygotes, indicating the presence of possible subclinical defect in copper transport in the heterozygotes as well.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 45 (1979), S. 111-115 
    ISSN: 1432-0533
    Keywords: Brain tumor ; Rhabdomyosarcoma ; Mesenchymal cell ; Myotube ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of primary cerebral rhabdomyosarcoma in a 51-year-old female is reported. The histogenesis of this tumor is discussed. The clinicopathological features of 10 previously reported similar tumors of the CNS are briefly reviewed. Histologically the tumor was polymorphic, but composed of poorly differentiated cells interpreted as rhabdomyoblasts without definite cross-striation. Electron microscopy established that the poorly differentiated cells were of rhabdomyosarcomatous nature, compatible with presumptive myoblasts and analogous to developing fetal muscle.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 46 (1979), S. 11-15 
    ISSN: 1432-0533
    Keywords: Meningioma ; Cell culture ; Ultrastructure ; Cell junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural alterations in human meningioma cells grown in vitro are reported. In early passages the cells retain some of the characteristic features of the original tumors. These include interdigitations associated with intercellular junctional devices (e.g., desmosomes, gap junctions). However, with repeated subculture these features tend to be less frequent. Typical whorl formations are observed only in primary cultures. The nunber of cytoplasmic filaments, lipid inclusions and other dense bodies increases with time in culture. Cytoplasmic invaginations into nuclei and the appearance of very large cells become more frequent in repeatedly transferred cultures.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 47 (1979), S. 85-92 
    ISSN: 1432-0533
    Keywords: Isoniazid ; Neuropathy ; Intoxication ; Dying back ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Large single doses of isoniazid by mouth (1–2 g/kg) have been shown to produce in rats Wallerian degeneration visible with the light microscope from the third day onwards. By contrast, changes in axons are seen from 24 h onwards by electron microscopy. The earliest ultrastructural changes are associated with vacuoles appearing between axon and Schwann cells. These are large and focal, and often compress the axon. The adjacent axon may show changes in smooth ER, and in microtubular arrangement. Alterations in smooth membranes and in mitochondria are visible in Schwann cell cytoplasm, not necessarily related to the vacuole formation and axonal features. It is suggested that INH neuropathy is essentially a multifocal axonal lesion.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 47 (1979), S. 75-79 
    ISSN: 1432-0533
    Keywords: Neurotoxicity ; Cyanate ; Demyelination ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of sodium cyanate (NaNCO) on the nervous system of Maccaca nemestrina were studied at 2, 4, and 6 months of administration of the drug. The two groups injected with daily doses of 35 and 25 mg/kg/day of Na-cyanate developed a predominantly demyelinating lesion in the pyramidal tracts of the spinal cord. No neuronal changes were observed in the motor cortex, basal ganglia, midbrain, medulla or anterior horn cells of the spinal cord. There was no evidence of peripheral neuropathy. A comparison between the cyanate induced neuropathy in the rat and in the primate was drawn. Ultrastructurally, both species developed a demyelinating process of central or peripheral myelin characterized by vacuolation of the myelin sheath, removal of myelin debris by macrophages and re-myelination. There was little evidence of axoplasmic damage except for an occasional distended fiber containing abundant dense bodies and whorls of neurofilaments. Oligodendrocytes and Schwann cells were electron microscopically intact and participated actively in remyelination. Maccacas maintained at 15 mg/day and sham animals remained normal clinically and anatomically. The predominantly myelinotoxic effect of cyanate is similar to that produced by other myelinotoxic agents and is attributed to a selective modification of myelin proteins by carbamylation.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 48 (1979), S. 211-214 
    ISSN: 1432-0533
    Keywords: Medullomyoblastoma ; Desmoplastic medulloblastoma ; Teratoid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of cerebellar medullomyoblastoma in a young boy was investigated by electron microscopy. The neuroectodermal component shows the characteristics of a desmoplastic medulloblastoma. The mesodermal component consists of more or less differentiated cross-striated muscle cells. Undifferentiated muscle cells are very similar to proliferated endothelial cells of blood vessels within the muscular component, so that an origin of this component from pluripotential endothelial cells of the vessel wall is suggested. This tumor is considered a malignant teratoid because of the derivation from two blastodermic layers and because of the midline localization in children suggesting a malformative origin.
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  • 18
    ISSN: 1432-0533
    Keywords: Melanin ; Melanosomes ; Ultrastructure ; Infrared spectrophotometry ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Melanosomes and isolated melanosomal fragments (melanin particles) originating from gangliocytes (substantia nigra), astroglia (melanosis cerebelli), and melanocytes (melanotic meningeoma; metastases of melanoblastoma; melanosis thalami of the goat) were compared with synthetic melanins prepared from dopamine and serotonin, respectively. Samples were examined by electron microscopy, X-ray diffraction analysis according to Debye-Scherrer and by infrared spectrophotometry, and the results were evaluated with regard to characteristic features as they may relate to specific cell types or chemical structures. On electron microscopy all three types of melanosomes could be differentiated unequivocally as could the two synthetic melanins. Thus, there were similarities between synthetic melanin from dopamine and the gliogenic melanins of the cerebellum; the synthetic melanin from serotonin resembled melanin of melanocytes. X-ray diffraction analysis yielded 2-4 Debye diffraction rings with all human and synthetic samples, suggesting short range orders between 3.8 to 5 Å the sample obtained from a goat with thalamic melanosis showed a specific reflex pattern. While diffraction patterns of some melanins were partially identical, in particular that of melanin from dopamine and melanin of substantia nigra and dentate nucleus, respectively, they were different for the various melanocytic melanins. Further investigations are required to determine whether these differences are due to disparities in basic chemical structures or conformations or else, to particular compositional features of the various types of melanocytes as they arise from benign or malignant tumors or a specific species. Infrared spectrophotometry at higher wave numbers revealed the well known patterns of melanins, which are not, however, very suitable, for their further differentiation. At lower wave numbers (‘fingerprinting’) melanin of substantia nigra and the glial melanin in melanosis cerebelli yielded additional absorption bands of identical configuration. In contrast to melanin from dopamine, melanin from serotonin exhibited a closely similar absorption pattern in this spectral range, suggesting that the neuroectodermal melanins may contain a component possibly arising from serotonin.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 45 (1979), S. 159-160 
    ISSN: 1432-0533
    Keywords: Tight junction ; Choroid plexus papilloma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four cases of choroid plexus papilloma (CPP) obtained at the time of surgical excision were examined by electron microscopy and compared with normal choroid plexus (CP) of mouse and chick. In apical tight junctions fusion of the two outer leaflets of the adjacent cytoplasmic membrane was verified as in CP. This fact suggests that there is a blood-CSF barrier not only in CP but also in CPP.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 48 (1979), S. 27-30 
    ISSN: 1432-0533
    Keywords: Progressive supranuclear palsy ; Neurofibrillary tangles ; Ultrastructure ; Straight tubule ; Twisted tubule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of neurofibrillary tangles in the hippocampal gyrus, substantia nigra, pontine nuclei and locus coeruleus of the brain was postmortem studied in a case of progressive supranuclear palsy. Straight tubules and twisted tubules were observed in both the cortical and subcortical neurofibrillary tangles. Most tubules appeared separately in each neuron but a few straight tubules were mixed with the twisted tubules in the cortical tangles. The implication and possible significance of this findings are discussed.
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  • 21
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    Electronic Resource
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    Acta neuropathologica 48 (1979), S. 189-197 
    ISSN: 1432-0533
    Keywords: Hamster brain cells ; Polyoma virus ; Tumorigenicity ; Ultrastructure ; Specific nervous proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphological characteristics of three clones of hamster brain cells transformed in vitro by polyoma virus and of the tumors obtained after subcutaneous grafting of these cells in syngenic animals are reported. These clones appeared to be glial in nature by light and electron microscopy. The initial tumors induced by the three clones presented astrocytic features both by electron microscopy and immunohistochemistry. Analysis of the subsequent in vivo passages showed a decrease in cell differentiation, which was accompanied by a decrease in the latency period; after 2 years of serial transplantation, the tumors seemed poorly differentiated gliomas. A control cell line of hamster cerebellar cells evolved similarly.
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  • 22
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    Archives of microbiology 122 (1979), S. 17-27 
    ISSN: 1432-072X
    Keywords: Gliding bacteria ; CO2-requiring ; Periodontal disease ; Gram-negative ; Ultrastructure ; Capnocytophaga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Gram-negative, anaerobic gliding bacteria were isolated from normal supragingival plaque and from periodontal lesions. Isolates could be divided into two size classes: small 2.4–4.2 μm×0.38–0.5 μm and large 4.8–5.8 μm×0.42–0.6 μm cells. The outer membrane was either loose-fitting and wavy, or taut, and of variable thickness. An electron-dense fuzz was discernible on several of the isolates. The periplasmic region was of variable electron-density. The genus Capnocytophaga has been proposed for these organisms based on morphological and cultural characteristics.
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  • 23
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 121 (1979), S. 53-59 
    ISSN: 1432-072X
    Keywords: Saccharomyces ; Kluyveromyces ; Ultrastructure ; Ascospore wall ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.
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  • 24
    ISSN: 1432-072X
    Keywords: Methanogenium cariaci ; Methanogenium marisnigri ; Marine methanogenic bacteria ; Ultrastructure ; TaxonomyMethanogenium gen. nov.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.
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  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 35 (1979), S. 249-267 
    ISSN: 1432-1106
    Keywords: Abducens nucleus (cat) ; Peroxidase ; Neurones ; Synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscope studies of the abducens nucleus in the cat have disclosed two populations of neurones: large neurones 25 to 75 μm in diameter and small neurones 10 to 25 μm in diameter. Characteristic of the large neurones are a highly developed granular endoplasmic reticulum and a large number of axo-somatic synapses. The small neurones have a poorly developed granular endoplasmic reticulum and comparative by few axo-somatic synapses. Injection of horseradish peroxidase (HRP) into the ipsilateral lateral rectus muscle has been used to identify abducens motoneurones which represent 65% of the total number of cells in the abducens nucleus and form part of the large cell population. The remaining unlabelled large neurones (30% of the large cell population) probably represent motoneurones of the retractor bulbi muscles, abducens motoneurones which have failed to transport the HRP, and possibly internuclear neurones. The small neurones (5% of the total cell population) were never labelled by HRP. Axo-somatic and axo-dendritic synapses are numerous. Many of the synaptic terminals form contacts with two or more different postsynaptic elements. Axo-axonic synapses and synapses on the initial segments of large neurones are also present. Nodal synapses and branching of myelinated axons are common findings. Finally, extended areas of close apposition between dendritic membranes are frequently observed.
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  • 26
    ISSN: 1432-1106
    Keywords: Rat ; Hypoglossal nucleus ; Ultrastructure ; Second axotomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The left hypoglossal nerve of adult male albino rats was prevented from regenerating to the tongue after a distal axotomy by implanting the proximal stump into normally innervated left sternomastoid muscle. Eighty-four days after implantation, the hypoglossal nerve was transected again and its regeneration to the tongue unimpeded. From 8 to 70 days after this second axotomy the left hypoglossal nuclei were processed for quantitative ultrastructural analysis. The first aim of this study was to compare regeneration success in the hypoglossal nucleus after second axotomy with that accompanying outgrowth of the hypoglossal nerve into denervated sternomastoid muscle. During quantitative analysis a second aim developed, of elucidating bouton/glial relationships. The second axotomy induced loss and return of subsurface cisterns, dispersal and reassembly of Nissl substance, increase and decrease of microglial numbers, slight further loss and partial return of boutons with clear spherical vesicles and symmetrical synapses, slight increase and decrease of boutons with clear flat vesicles and symmetrical synapses, regrowth of retracted dendrites and restoration of their synapses, and gradual diminution of numbers of electron-dense neurones and dendrites. Astrocytes remained hypertrophied throughout. When compared with events in the hypoglossal nucleus accompanying innervation of denervated sternomastoid muscle by the hypoglossal nerve, the results suggest (1) that regeneration of the hypoglossal nerve to its own tongue muscle instead of to a foreign muscle caused no acceleration of recovery in the hypoglossal nucleus, and (2) that the microglial response is dependent on nerve integrity and not on bouton behaviour.
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  • 27
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    Virchows Archiv 381 (1979), S. 189-203 
    ISSN: 1432-2307
    Keywords: Pseudomalignant ossifying myositis ; Ultrastructure ; Myofibroblasts ; Macrophages ; Pathogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven cases of pseudomalignant ossifying myositis with a typical clinical symptomatology have been reported. None of the cases had experienced an injury. All the lesions were intramuscular and all of them showed a zonal arrangement. Electron microscopy in three cases allowed the demonstration of cells showing morphological features of myofibroblasts and monocytic cells of the macrophage type. These previously unreported features together with the zonal pattern of the lesions indicate their reparative nature.
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  • 28
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    Virchows Archiv 382 (1979), S. 191-200 
    ISSN: 1432-2307
    Keywords: Rheumatoid arthritis ; Muscle spindles ; Neuromuscular spindles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural features of muscle spindles were studied in biopsy material from 100 patients suffering from classical rheumatoid arthritis. Thickening of the outer capsule, increased amount of extracellular ground substance within the inner capsule, and marked thickening of the basement membrane of capillary blood vessels supplying the muscle spindles were observed. Chronic inflammatory cells and macrophages were present within the spindles. Changes affecting the intrafusal muscle fibres were also seen. They were manifest as atrophy and degeneration of the intrafusal muscle fibres, absence of the specialised junctional complexes, and of the intercellular bridges, microladders and satellite cells. It is suggested that the changes affecting the intrafusal muscle fibres are probably secondary. Damage to the myelinated nerves was present, while the sensory and motor nerve endings were well preserved.
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  • 29
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    Virchows Archiv 385 (1979), S. 77-91 
    ISSN: 1432-2307
    Keywords: Ultrastructure ; Ovary ; Clear cell carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of an ovarian clear cell carcinoma in a 65 year old woman was analysed. The tumor cells were of both clear and “hobnail” types. Both were characterized by the presence of short microvilli, abundant glycogen granules, a well-developed granular endoplasmic reticulum and Golgi apparatus, scanty lysosomes and very few lipid bodies. The tubules and gland-like spaces were always separated from the stroma by a basement membrane. At ultrastructural level the tumor cells do not resemble at all those of clear cell renal carcinomas. On the other hand, their submicroscopic features are strongly similar to those of the clear cell tumors found elsewhere in the female genital tract, emphasizing therewith their very probable müllerian origin. It is recommended to eliminate the term “mesonephroma ovarii” to designate the clear cell carcinomas of the ovary.
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  • 30
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    Virchows Archiv 381 (1979), S. 313-329 
    ISSN: 1432-2307
    Keywords: Bronchial carcinoids ; Different types ; Cells of origin ; Ultrastructure ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven of eleven bronchial carcinoids investigated showed cells with small granules resembling P cells which have already been described in human fetal and adult lung; two of these P cell tumours showed distinctive paraganglioid features. One tumour showed peculiar ultrastructural findings resembling closely those previously reported by Black (1969) in a so called “pulmonary oncocytoma”. Three remaining cases showed large secretory granules resembling those of type 3 cells already described by Hage (1973 b) in bronchial carcinoids; one of these tumours produced large amounts of 5-hydroxytryptamine (5HT). It is concluded that, on cytological grounds, at least two types of tumours can be distinguished among bronchial carcinoids, i.e. P cell and type 3 cell tumours. Moreover, two varieties of P cell carcinoids have been recognized, showing either the less frequent and more distinctive paraganglioid structure or the more common trabecular structure.
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  • 31
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    Virchows Archiv 385 (1979), S. 93-101 
    ISSN: 1432-2307
    Keywords: Angioma ; Lung ; Carcinoma ; Pneumocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Elektronenmikroskopische Untersuchung eines sog. sklerosierenden Hämangioms der Lunge, das im Oberlappen einer 32jährigen Frau zufällig entdeckt wurde. Der seltene gutartige Tumor, der lichtmikroskopisch wegen seines Gefäßreichtums an ein Hämangiom erinnert, zeigt elektronenmikroskopisch eine eindeutige epitheliale Struktur. Die Geschwulst entwickelt sich möglicherweise aus unreifen Pneumocyten. Histogenese sowie differential-diagnostische Probleme (Verwechslungsmöglichkeit mit Carcinom) werden diskutiert.
    Notes: Summary Electron microscopy of a sclerosing angioma of the lung, a coincidental finding in the upper lobe of a 32-year-old woman. The rare, benign tumor, whose vascular proliferation by light microscopy is reminiscent of an angioma, exhibits a clear epithelial structure by electron microscopy. The tumor may develop out of immature pneumocytes. The paper discusses histogenesis and problems of differential diagnosis (potential confusion with carcinomas).
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  • 32
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    Virchows Archiv 381 (1979), S. 121-139 
    ISSN: 1432-2307
    Keywords: Myxofibrosarcoma ; Fibroblast ; Histiocyte ; Myofibroblast ; Sarcoma ; Soft tissue tumour ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study of 11 myxofibrosarcomas is presented. The tumours were graded light-microscopically on a four-point scale according to cellularity, cell atypia and mitotic activity, as described in a previous paper: 3 were grade I, 2 grade II, 4 grade III and 2 grade IV. Fibroblast-like and myofibroblast-like cells predominated in the grade I and II tumours, while histiocyte-like cells were relatively few; in grade III and IV tumours histiocyte-like cells predominated. The fibroblast-like cells were spindle-shaped with fairly smoothly outlined nuclei, and contained abundant parallel membranes and wide cisternae of endoplasmic reticulum. The histocyte-like cells were irregular in shape and showed indented nuclei with large nucleoli and coarse, peripherally arranged clumps of heterochromatin. The cytoplasm of these cells showed prominent pseudopodiae, microvillous projections, conspicuous systems of vesicles and vacuoles, inclusions of lipid and pigment, numerous lysosomal structures and large digestive vacuoles indicating auto- and exophagocytosis. The myofibroblast-like cells showed abundance of parallelly arranged cytoplasmic microfilaments with dense body-like structures and condensation at the plasmic membrane. Occasional cells appeared to be intermediate forms and primitive looking, undifferentiated cells were also encountered. A few multinucleated tumours cells were seen in the grade IV tumours. Thus, the present study shows the composite fibroblastic, myofibroblastic and histiocytic character of the tumour cells of myxofibrosarcoma; the grade III and IV tumours, with a tendency to contain solid areas, seem to be closely related to the pleomorphic type of malignant fibrous histiocytoma.
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  • 33
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    Virchows Archiv 381 (1979), S. 159-178 
    ISSN: 1432-2307
    Keywords: Giant cell tumor ; Ultrastructure ; Acid phosphatase ; Lysosomes ; Bone tumors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eleven benign giant cell tumors of bone were studied in the electron microscope, and the fine structural localization of acid phosphatase was elucidated. Three distinct cell types are always present in these tumors: stromal cells type 1; stromal cells type 2; and multinucleated giant cells. Small mononuclear cells may also occur, but are not likely to be actively participating in the neoplastic process. The range of variability in the fine structure of the different cell types constituting this tumor has been established. Variations in appearances include: a) presence of nuclear pseudoinclusions in stromal cells type 1 and multinucleated giant cells; b) aberrations in the structure of the rough surfaced endoplasmic reticulum in the same cell types; c) occurrence of ruffled borders, ectoplasmic layers and cytoplasmic labyrinths containing acid phosphatase in the giant cells. Some giant cells show evidence of marked phagocytic activity and contain large and numerous residual bodies carrying acid phosphatase. The significance of the interrelations between the different cell types are discussed and the possible role of stromal cells type 2 in immunological mechanisms directed against the tumor cells are mentioned.
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  • 34
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    European archives of oto-rhino-laryngology and head & neck 224 (1979), S. 31-35 
    ISSN: 1434-4726
    Keywords: Intracellular potentials ; Ultrastructure ; Hair cells ; Labyrinth receptors ; Reptilia (Crocodilia, Gekkonidae)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Different biopotentials, following a mechanical stimulus, were recorded from single hair cells of the reptilian labyrinth, with electronoptically circumscript localizations: 1. From the apical cell pole, the receptor potential, intracellular or from the ciliary surface, within the physiological range proportional to stimulus amplitude, frequency or phase, without delay, and with no real threshold of mechanosensitivity, as measured by ciliary displacement amplitude or velocity. 2. From the synaptic zone, in the basal region of the hair cell, or from contacting nerve endings, the synaptic potentials, local excitatory or inhibitory processes, respectively, with measurable latencies and with non-linear distortion. 3. From the (dendritic) endings of the first afferent neuron (or neurons), spike-shaped action potentials, synchronized by the (excitatory) synaptic potentials. Characteristic curves were plotted as a quantitative representation of the mechano-electric input-output relations of the different types of hair cells. For proceeding morphological and physiological system analysis, the comparison of the different submammalian inner-ear receptor systems gives us some new possibilities of a closer correlation between ultrastructure and function.
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  • 35
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    European archives of oto-rhino-laryngology and head & neck 225 (1979), S. 57-65 
    ISSN: 1434-4726
    Keywords: NZB/NZW-Maus ; Ultrastruktur ; Submandibulare Speicheldrüse ; Lymphocyten ; Autoimmunes Leiden ; NZB/NZW mouse ; Ultrastructure ; Submandibular gland ; Lymphocytes ; Autoimmune disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary An electron microscopic study of the submandibular salivary gland lesion occurring in the NZB/NZW F1 hybrid mice was performed, and the findings were discussed and correlated to the autoimmune salivary gland disease observed in patients with Sjögren's syndrome. Within the submandibular salivary gland of this mouse strain focal infiltrates of mononuclear inflammatory cells were observed. Lymphoid cells were observed inside the basal lamina of acini and ducts, leading to destruction of these glandular units. The typical duct cell proliferation found in the autoimmune sialoadenitis of Sjögren's syndrome with the formation of the typical epimyoepithelial islands was not found in the submandibular glands of NZB/NZW mice.
    Notes: Zusammenfassung Eine elektronenmikroskopische Untersuchung der bei den NZB/NZW F1 hybriden Mäusen vorkommenden Veränderungen in den submandibularen Speicheldrüsen wurde durchgeführt, und die Befunde wurden diskutiert und korreliert mit dem autoimmunen Speicheldrüsenleiden, das bei Patienten mit Sjögrens-Syndrom beobachtet wird. In der submandibularen Speicheldrüse dieses Mäusestammes wurden begrenzte Infiltrationen mononuklearer inflammatorischer Zellen beobachtet. Die mononuklearen Zellen wurden hauptsächlich als lymphoide Zellen identifiziert. Außerdem wurden innerhalb der Lamina basilaris von Drüsen und Drüsengängen lymphoide Zellen beobachtet, die zur Zerstörung dieser Drüseneinheiten führen. Darüber hinaus wurde der typische Zuwachs der Drüsengangszellen, der bei der autoimmunen Speicheldrüsenentzündung des Sjögrens-Syndroms vorkommt und die Form von typischen epimyoepithelialen Inseln annimmt, in den submandibularen Drüsen der NZB/NZW-Mäuse nicht vorgefunden.
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  • 36
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    Journal of cancer research and clinical oncology 95 (1979), S. 225-232 
    ISSN: 1432-1335
    Keywords: Cultured tumour cells ; Ultrastructure ; 3-D Colonies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cultured hepatocellular carcinoma cells were studied during anchorage-independent growth in semi solid medium (Methocel). The regular occurrence of mitotic figures both at the surface and within the colonies precludes the possibility of such colonies being formed by re-aggregation. The estimated population doubling time in the three-dimensional (3-D) colonies is consistent with those two-dimensional of (2-D) colonies. Structures resembling bile canaliculi were observed between the closely opposed membranes from the well packed adjacent cells. Cell surface and ultrastructural features of the colonies and individual cells are presented and comparisons made with 2-D growth of normal and malignant liver cells in vitro. The formation of 3-D colonies may not only be an assay for transformed cells but also for predicting the type of tumors produced by re-innoculation of the in vitro transformed cells.
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  • 37
    ISSN: 1615-6102
    Keywords: Ciliata ; Crystals ; Euplotes ; Lithosomes ; Microanalysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the cytoplasm of the marine ciliateEuplotes vannus, there exist two conspicuous types of membrane bound inclusions: 1. irregularly shaped crystals which are highly anisotropic; 2. globular lithosomes characterized by concentrically arranged layers of deposits which exhibit only faint birefringence. Normally, both structures form distinct accumulations. Energy dispersive X-ray microanalysis of these accumulations reveals a high content of calcium and phosphorus, besides magnesium, sulphur and chlorine. Analysis of cell areas devoid of the inclusions show significantly lower calcium- and phosphorus-peaks.
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  • 38
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteogenesis ; Fish bone ; Osteocytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The comparative ultrastructure of fish bone osteogenesis and resorption induced by scale removal was described in the osteocytic (cellular-boned)Carassius auratus and the anosteocytic (acellular-boned)Tilapia macrocephala. Osteocytes, present in osteocytic bone, were lacking in anosteocytic bone. In osteocytic bone the osteoblast secreted a collagenous preosseous matrix in which it became enmeshed and then was termed a preosteocyte. When the preosseous matrix mineralized, the preosteocyte was termed an osteocyte and was completely surrounded by bone. In anosteocytic bone the osteoblasts receded from the mineralizing front and never became trapped as osteocytes. During resorption, types A and B resorptive cells, present in both bone types, invaded the matrix and demineralized the osseous zone. These cells were characterized by large amounts of granular endoplasmic reticulum and intracellular inclusions containing crystal-like material. Although functionally similar to mammalian osteoclasts, these cells lacked a characteristic ruffled border and were not multinucleated. The osteocytes of cellular bone did not appear to be involved during demineralization.
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  • 39
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    Research in experimental medicine 176 (1979), S. 69-79 
    ISSN: 1433-8580
    Keywords: Skeletal muscle ; CO2-laser ; Surgery ; Ultrastructure ; Rat ; Skelettmuskelfaser ; CO2-Laser ; Chirurgie ; Ultrastruktur ; Ratte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Zustand der dorsalen Haut und des darunterliegenden Muskelgewebes der Ratte wurde unmittelbar nach CO2-Laser-Schnitten mit Hilfe von licht- und elektronenmikroskopischen Methoden untersucht. In der subkutanen Skelettmuskelschicht konnte eine erhöhte Empfindlichkeit des Gewebes festgestellt werden, die in einer ausgeprägten Abfolge von Zellveränderungen ihren Ausdruck findet. Diese Schädigungen werden hauptsächlich den thermischen Effekten der Laserstrahlung zugeschrieben. Die Bedeutung dieser Untersuchungsergebnisse in Hinblick auf die Verwendung von Laser in der Chirurgie wird besprochen.
    Notes: Summary The immediate effect of CO2-laser incision to the dorsal skin and underlying muscular tissue of rats was studied by light and electron microscopical methods. In the subcutaneous layer of skeletal muscle cells an increased susceptibility was found, resulting in distinct zones of cellular changes which are attributed mainly to thermal effects of the laser beam. The importance of these findings for the surgical application of lasers is discussed.
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  • 40
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    Virchows Archiv 384 (1979), S. 307-324 
    ISSN: 1432-2307
    Keywords: Calcifying odontogenic cyst ; Dysplastic dentin ; Hornified cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four new cases of calcifying odontogenic cyst (COC) were studied by light- and electronmicroscope. The ages of the patients were between 20 and 68 years. Three cysts were located in the maxilla, the other was in the mandible. The history of two patients was followed up for five and ten years respectively. The longer the history the bigger were the cysts. All cysts showed histologically identical alterations of the epithelium with 1) a pronounced cylindrical basal cell layer, 2) cells resembling stellate reticulum, and 3) ghost cells. So called dysplastic dentin was laid down in the connective tissue only in the two cases with a long history. Ultrastructurally the odontogenic epithelium of all cysts showed keratinization similar to the epidermis. Two types of keratinization are known to occur in the epidermis, soft keratinization with keratohyalin granules in ortho- and parakeratosis, and hard keratinization without keratohyalin granules in nails (horn). Both types of keratinization occur in odontogenic epithelium. The COC is an example of hard keratinization. Ghost cells form prekeratin which in turn becomes horn and is found in areas of confluent ghost cells and in the so called dysplastic dentin. We conclude that the alteration of odontogenic epithelium in COC and in special odontogenic tumors is a secondary phenomenon resembling ortho- and parakeratosis.
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  • 41
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    Virchows Archiv 384 (1979), S. 347-355 
    ISSN: 1432-2307
    Keywords: Exfoliation syndrome ; Non-glaucomatous eye ; Trabecular meshwork ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The trabecular meshwork of a non-glaucomatous eye with the exfoliation syndrome was investigated. The exfoliation material was found mainly in massive deposits in the subendothelial region of the outer and inner wall of Schlemm's canal, in the cribriform area and the uveal meshwork. The other alterations of the trabeculum corneosclerale corresponded to the age of the patient. The concept that the accumulation of exfoliation material is an important pathogenetic factor in the development of glaucoma was not confirmed by this study.
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  • 42
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    Virchows Archiv 384 (1979), S. 93-102 
    ISSN: 1432-2307
    Keywords: Primary aldosteronism ; Adrenal adenomata ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adenomata taken from 25 patients with primary aldosteronism were observed by electron microscopy. The cells in the adenoma had a well developed agranular endoplasmic reticulum but granular endoplasmic reticulum was not prominent. Most of the mitochondria resembled those in the cells of the zona glomerulosa, suggesting that the adenomata which caused primary aldosteronism are derived from this zone. Spironolactone bodies were found in the cells of the adenoma from a patient who received spironolactone. Their appearance was identical to that descrived in previous reports.
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  • 43
    ISSN: 1432-2307
    Keywords: Hexachlorobenzene ; Liver ; Ultrastructure ; Porphyrins ; Smooth endoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Groups of female rats were treated orally with 0.5, 2.0, 8.0, and 32 mg/kg hexachlorobenzene twice a week for 203 days. The liver content of hexachlorobenzene was found to be dose-dependent. In the animals treated with the highest dose the concentration was 273 μg/g hexachlorobenzene. In the fresh and fixed hepatic tissue of the treated animals pink fluorescence was observed. Electron microscopy revealed a dose dependent enlargement of all hepatocytes due to proliferation of the SER in the centrolobular area or to increased glycogen deposits (β- or α-particles) and SER in the intermediary and periportal area. Numerous porphyrin deposits and siderosomes, intimate disorganisation and moderate dislocation of the RER and a moderate enlargement of bizarre-shaped mitochondria were recognized. The relationship between porphyrin crystals and mitochondria on the one hand and between SER and glycogen deposits on the other is discussed.
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  • 44
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    Virchows Archiv 382 (1979), S. 201-216 
    ISSN: 1432-2307
    Keywords: Meningioma ; Ultrastructure ; Classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined 23 meningiomas by electron microscopy. In each case it was possible to distinguish certain cells with epithelial features (desmosomes, microfilaments, interdigitating extensions) and others with fibroblastic features (collagen fibers). Others cells of transitional form were also seen. The proportion of these cellular types is variable, making it possible to classify meningiomas into seven types progressing gradually from a purely epithelial type to a purely fibroblastic one. We found no important ultrastructural abnormalities in the cells. These case reports confirm the uniqueness of meningiomas, which are composed of variously shaped cells but have their origin from a single cellular type. This has double potentiality for fibroblastic and epithelial differentiation.
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  • 45
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    Virchows Archiv 382 (1979), S. 217-226 
    ISSN: 1432-2307
    Keywords: Axonal swelling ; Spheroid ; Dystrophic axon ; Ultrastructure ; Human gracile nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology of the spheroids in human gracile nuclei was studied by light and electron microscopy. Various spheroids encountered in the present study could be classified into three types based on the internal structure: The first one was chiefly composed of many irregular homogeneous dense bodies, multivesicular bodies and mitochondria. The dense bodies seemed to deposit multicentrically in an axon in the early stage of “balloon” formation and coalesce to form larger ones. The second was characterized by a marked accumulation of closely approximated mitochondria and dense concentric bodies. In the third the most characteristic findings were neurofibrillary accumulation and aggregations of dense bodies. These findings showed some divergence from those of dystrophic axons and the last two mimic those of degenerative or regenerative axons, which suggested that axonal swelling (including dystrophic axon) is not characteristic reaction of specific disease but rather nonspecific one to a variety of noxious stimuli. With light microscope, it was difficult to distinguish balloons with different structures since they were quite diverse and manifold in their shape, size, appearance and stainability. Intra-axonal corpora amylacea were seen in most cases and their incidence appeared to be nonspecific for any diseases.
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  • 46
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    Virchows Archiv 382 (1979), S. 237-243 
    ISSN: 1432-2307
    Keywords: Giant cell tumors of tendon sheath ; Soft tissue tumors ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A benign, but aggressive, giant cell tumor of tendon sheath developed over a period of 20 years into a metastasizing, histologically malignant giant cell tumor. Ultrastructure of the malignant tumor showed the same five cell types as described in giant cell tumors of tendon sheath. Even the same crystals were identified in the osteoblast-like and osteoclast-like cells. It therefore appears reasonable to assume that giant cell tumors of tendon sheath indeed are neoplasms with a malignant potential and not an inflammatory reaction of synovial cells as previously suggested. Both the benign and malignant tumors seem to be of mesenchymal derivation with partial osseous differentiation. No ultrastructural similarities with fibrous histiocytoma were apparent.
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  • 47
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    Virchows Archiv 383 (1979), S. 181-193 
    ISSN: 1432-2307
    Keywords: Graves' disease ; Preoperative treatment ; Ultrastructure ; Antithyroid drug treatment ; Lithium ; Cellular involution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This electron microscopic study is based on 12 cases of toxic goiter treated preoperatively with iodide, thionamides and lithium. Essential features of Graves' disease include hypertrophy of the follicular epithelium, papillary follicular infoldings and frequently, lymphocytic infiltration and fibrosis. After preoperative therapy most thyroid glands show involutional changes of varying degree with reaccumulation of colloid and flattening of the follicular epithelium. In a small number of histologically examined cases (n=84) colloid goitre (13%) and nodular goitre (8%) were noted. Lymphocytic infiltration and interstitial fibrosis do not show any correlation with preoperative treatment. Ultrastructurally, different stages of cellular involution are seen. The hypertrophic follicular cell shows an increased cell surface with numerous long microvilli and some pseudopodia at the apical border and an occasionally thickened, basal lamina. The cytoplasm contains a well developed system of organelles which synthesizes (rough endoplasmic reticulum, Golgi apparatus, cytoplasmic vesicles) and degrades (colloid droplets, lysosomes) thyroglobulin. With increasing cellular atrophy we found cells to be reduced in size but to contain well developed thyroglobulin-synthesizing organelles. Finally, we observed completely atrophic flat cells with only a few organelles. There are at date no electron microscopic communications on lithiumpretreated thyroid glands. After lithium therapy characteristic changes are observed at the membranes of the cytocavitary system, which are often found to be thin and occasionally to be damaged. The rough endoplasmic reticulum is virtually deprived of ribosomes and the Golgi apparatus seems to be underdeveloped. The number of apical microvilli is reduced. The morphological findings following iodide-, thionamide- and lithium pretreatment in Graves' disease are discussed in light of recent biochemical results.
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  • 48
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    European archives of oto-rhino-laryngology and head & neck 225 (1979), S. 165-180 
    ISSN: 1434-4726
    Keywords: Lymphatics ; Larynx ; Lymphangioscopy ; Ultrastructure ; Lymphgefäße ; Kehlkopf ; Lymphangioskopie ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Lymphdrainage des menschlichen Kehlkopfes wurde an autoptischem und in vivo Material lymphangioskopisch registriert. Auf ultrastruktureller Ebene erfolgte die Untersuchung des morphologischen Aufbaus von Lymphkapillaren und Lymphsammelgefäßen. Im Elektronenmikroskop zeigt der Wandaufbau der Lymphgefäße des Kehlkopfes nur geringgradige Unterschiede zum Lymphgefäßsystem anderer Körperregionen. Diese Unterschiede finden sich vor allem im Wandklappenaufbau der Lymphsammelgefäße. Eine strenge Kompartmentierung einzelner Kehlkopfregionen läßt sich nicht nachweisen. Ausnahme bilden die Lymphkapillaren des freien Randes der Stimmlippe. Anastomosen der Lymphkapillaren und -sammelgefäße erlauben Mittelinien- und Kehlkopfetagen-überschreitende Lymphdrainagen. Diese bestehenden Kollateralabflüsse sind bei Behinderung der physiologischen Lymphdrainage von klinischer Bedeutung.
    Notes: Summary From post mortem and in vivo tissues, the lymphatic drainage of the human larynx has been evaluated by means of lymphangioscopy. The fine structure of lymphatic capillaries and collecting vessels was examined in an electron microscope study. At the ultrastructural level, the structural components of the laryngeal lymphatic vascular wall showed only minor differences when compared to other lymphatic tissues. These differences concerned the valvular morphology of the lymphatic collecting vessels. There was no evidence of specific lymphatic drainage for distinct laryngeal areas, with the exception of the lymphatic capillaries of the free margin of the vocal cords. On account of anastomoses of lymphatic capillaries and collecting vessels lymphatic drainage could cross over both the laryngeal midline and other laryngeal levels. In pathological conditions with impediment of lymphatic flow, these collateral communications are of clinical significance.
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  • 49
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    Archives of dermatological research 266 (1979), S. 239-251 
    ISSN: 1432-069X
    Keywords: Cutaneous malignant B-cell lymphoma ; Ultrastructure ; Semithin sections ; Cutane maligne B-Zell Lymphome ; Ultrastruktur ; Semidünnschnitte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Achtzehn Fälle von cutanen B-Zell Lymphomen von niedrigem Malignitätsgrad (gesichert durch Enzymcytochemie und Immuncytologie) wurden morphologisch mittels Semidünn- und Dünnschnitten unter-sucht. Vier Typen mit einem charakteristischen Muster von verschiedenen lymphoiden Zellen wurden gefunden: (1) Der lymphocytische Typ, überwiegend aus kleinen Lymphocyten bestehend; (2) der lymphocytoide (zentrocytische oder prolymphocytische) Typ, bei dem neben kleinen auch mittelgroße Lymphocyten (mit und ohne geknitterten Zellkernen) erscheinen; (3) der lymphoplasmacytoide Typ, bei dem neben kleinen und mittelgroßen Lymphocyten lymphoide Zellen mit unterschiedlich ausgeprägten Differenzierungsmerkmalen von Plasmazellen zu finden sind; sowie (4) der zentroblastische-zentrocytische Typ. Hier sind neben kleinen und mittelgroßen Lymphocyten auch Zentroblasten zu beobachten. Insgesamt stimmen die hier erhobenen morphologischen Befunde gut mit entsprechenden nodalen malignen Lymphomen überein. Die Anwendung moderner Klassifikationen von non-Hodgkin Lymphomen, insbesondere die »Kiel-Klassifikation«, erscheint daher auch für die Hautlymphome gerechtfertigt. Dünn- und Semidünnschnitte eignen sich bei der Routinediagnostik von derartigen Krankheitsfällen, vor allem dann, wenn mit Paraffinschnitten keine klare diagnostische Einordnung erfolgen konnte.
    Notes: Summary Eighteen cases of low grade malignant B-cell lymphomas (confirmed through enzyme cytochemistry and immunocytology) were investigated morphologically using thin and semithin sections. Four types with a characteristic pattern of different lymphoid cells were found: (1) the lymphocytic type, predominantly consisting of small lymphocytes; (2) the lymphocytoid (centrocytic or prolymphocytic) type, in which in addition to small lymphocytes medium-sized lymphocytes (with or without cleaved nuclei) are found; (3) the lymphoplasmacytoid type, where lymphoid cells with different degrees of similarity to plasma cells are seen as well as small and medium-sized lymphocytes; and (4) the centroblastic-centrocytic type, in which centroblasts are present next to small and medium-sized lymphocytes. These findings correlate well with the morphological observations in low-grade malignant B-cell lymphomas of the lymph nodes. Therefore, the application of modern classifications of non-Hodgkin lymphomas, such as the “Kiel Classification”, to cutaneous lymphomas appears justified. Thin and semithin sections are particularly useful in suspected cases of cutaneous malignant lymphoma, in which paraffin sections did not allow the diagnosis to be established.
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  • 50
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    Archives of dermatological research 266 (1979), S. 187-196 
    ISSN: 1432-069X
    Keywords: Disseminated lipogranulomatosis ; Farber's disease ; Sphingolipidoses ; Ceramide ; Ultrastructure ; Disseminierte Lipogranulomatose ; M. Farber ; Sphingolipidosen ; Ceramid ; Ultrastruktur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine elektronenmikroskopische Untersuchung von 2 Hautläsionen bei einem aus der Türkei stammenden 2jährigen Jungen mit disseminierter Lipogranulomatosis (Farber) zeigte curvilineare Körper in Fibroblasten, Histiocyten und Endothelzellen, flache Membrananordnungen in Fibroblasten und Endothelzellen und spindelartige Körper in Schwann-Zellen. In peripheren Lymphocyten fanden sich nur Veränderungen der Mitochondrien (Schwellung und aufgebrochene Cristae), jedoch keine Einschlußkörper. Die intracytoplasmatischen curvilinearen Körper waren zahlreich und leicht nachweisbar. Sie scheinen für den M. Farber spezifisch zu sein, und es wird vorgeschlagen, sie “Farber Körper” zu nennen. Die Diagnose dieser Ceramidspeicherkrankheit, in der das histologische Bild weitgehend unspezifisch ist, kann daher ultrastrukturell bestätigt werden.
    Notes: Summary An ultrastructural investigation of two cutaneous lesions in a two-year-old Turkish boy with disseminated lipogranulomatosis (Farber) revealed curvilinear bodies in fibroblasts, histiocytes, and endothelial cells; “elongated membranes” in fibroblasts and endothelial cells; “zebra bodies” in endothelial cells; and spindle-shaped bodies in Schwann cells. In peripheral lymphocytes only alterations of mitochondria (swelling and ruptured cristae) but no inclusion bodies were found. Curvilinear bodies were numerous and easily identifiable; they appear to be characteristic of Farber's disease, and naming them “Farber bodies” is proposed. The diagnosis of this ceramide storage disease, in which the histological examination is relatively unspecific, can therefore be confirmed ultrastructurally.
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  • 51
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    Archives of dermatological research 264 (1979), S. 17-28 
    ISSN: 1432-069X
    Keywords: Malignant lymphoma ; Mycosis fungoides ; Sezary's syndrome ; Parapsoriasis en plaques ; Ultrastructure ; Semi-thin sections ; Maligne Lymphome ; Mykosis fungoides ; Sézary-Syndrom ; Parapsoriasis en plaques ; Ultrastruktur ; Semi-Dünnschnitt-Technik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Semi-Dünnschnitte erlauben eine bessere morphologische Differenzierung von lymphoiden Zellen als Paraffinschnitte. Zur Prüfung ihrer möglichen Bedeutung bei der Diagnostik von kutanen T-Zell-Lymphomen wurden folgende Untersuchungen durchgeführt: Lymphoide Zellen im cellulären Infiltrat von Hautläsionen bei Mykosis fungoides (11 Fälle), Sézary-Syndrom (9 Fälle) und Parapsoriasis en plaques (14 Fälle) wurden mittels Semi-Dünnschnitten von Epon-eingebetteten Biopsien quantitativ analysiert. Als Kontrollen wurden Biopsien von Epikutan-Test-Reaktionen, Kontaktdermatitis, initialer Psoriasis und Erythema chronicum migrans untersucht. Eine hohe Prozentzahl von Lutzner-(Sézary)-Zellen fand sich ständig beim Sézary-Syndrom und gelegentlich bei der Parapsoriasis en plaques. Bei der Mycosis fungoides überwogen lymphocytoide Zellen mit helleren Kernen als bei normalen Lymphocyten. In den meisten Tumorläsionen sowohl bei der Mycosis fungoides als auch beim Sézary-Syndrom fand sich eine erhöhte Prozentzahl von Immunoblasten. Lymphocyten waren der häufigste Zelltyp bei der Parapsoriasis en plaques und bei den Kontrollen. Diese Befunde könnten nützlich für die Diagnostik von Problemfällen sein, für die die Semi-Dünnschnitt-Technik als eine weitere Methode empfohlen wird.
    Notes: Summary Semi-thin sections are superior to paraffin sections for differentiating lymphoid cells. To test their possible significance in the diagnosis of cutaneous T-cell lymphomas, the following investigation was made: A quantitative analysis of lymphoid cells in the cellular infiltrate of cutaneous lesions of mycosis fungoides (11 cases), Sézary's syndrome (9 cases), and parapsoriasis en plaques (14 cases) was made using semi-thin sections of eponembedded biopsies. As controls biopsies of patch test reactions, contact dermatitis, initial psoriasis, and erythema chronicum migrans were studied. A high percentage of Lutzner (Sézary) cells was consistently found in Sézary's syndrome and occasionally in parapsoriasis en plaques only. In mycosis fungoides lymphocytoid cells with the nuclei, less dense than in normal lymphocytes were predominant. In most tumorous lesions of mycosis fungoides and of Sézary's syndrome an increased percentage of immunoblasts was noted. Normal lymphocytes were the most frequent cell type in parapsoriasis en plaques as well as in the controls. These findings may prove helpful in the diagnosis of problem cases, for which the use of semi-thin sections is recommended.
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  • 52
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    Archives of dermatological research 266 (1979), S. 143-159 
    ISSN: 1432-069X
    Keywords: Xanthoma ; Ultrastructure ; Lipid vacuoles ; Myelin figures ; Xanthoma ; Ultrastruktur ; Lipidvacuolen ; Myelinfiguren
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine elektronenmikroskopische Untersuchung von 10 Patienten mit normolipämischer Xanthomatose und von 2 Patienten mit hyperlipoproteinämischer Xanthomatose Typ IV und V ergab folgende Befunde: In allen Fällen wurden große Mengen von Histiocyten mit intracytoplasmatischen Lipid-Vacuolen, Lysosomen und Myelinfiguren gesehen. Dazu waren Mikrofilamente und Lipid-Vacuolen in einigen Fibroblasten zu beobachten. In sämtlichen Präparaten fanden sich mehrkernige histiocytäre Riesenzellen mit kristallinen Spalträumen sowie einige Mastzellen. Lipid-Vacuolen konnten auch in Schwannzellen, Endothelzellen und in Pericyten nachgewiesen werden. In einigen Endothelzellen und Pericyten beobachtete man Duplikaturen der basalen vaskulären Laminae und “rob-shaped” tubuläre Körperchen. Beim Xanthelasma palpebrarum und dem Xanthoma planum disseminatum fanden sich die histiocytären Schaumzellen in perivaskulärer Anordnung, wie bei den hyperlipoproteinämischen Xanthomatosen. Wir folgern, daß die ultrastrukturellen Aspekte in den verschiedenen Xanthomatosen im wesentlichen gleich sind, zumal große Ablagerungen von Fett in allen Zellen zu sehen sind. In den normolipämischen Xanthomatosen (Xanthelasma palpebrarum und Xanthoma planum disseminatum) ist die Art der Entstehung von Fettablagerungen vermutlich die gleiche wie bei den hyperlipoproteinämischen Xanthomatosen; sie unterscheiden sich jedoch von den Fettablagerungen beim Xanthoma disseminatum und beim Xanthogranuloma juvenile. Eine Einteilung der normolipämischen Xanthomatosen wird vorgestellt.
    Notes: Summary Electron microscopic aspects in ten cases of normolipidemic cutaneous xanthomatosis have been investigated. Two additional types IV and V hyperlipoproteinaemic xanthomatosis have also been included. Ultrastructural findings in all cases were similar. Abundant histiocytic cells with numerous intracytoplasmic lipid vacuoles, lysosomes, and myelin-figures, were the striking features. Moreover, in older lesions microfilaments and lipid vacuoles were found in some fibroblastic cells, as well as long space collagen around them. In some specimens we observed: giant multinucleated histiocytic cells, crystalline cleft-like spaces in histiocytes and some mastocytes with lipidic crystals in the extracellular space, as well as lipid vacuoles in Schwann cells, endothelial cells and pericytes. Rod-shaped tubulated bodies were found in some endothelial cells, with multiple basal vascular laminae. In xantelasma palpebrarum and in disseminate plane xanthoma the histiocytary foamy cells adopted a perivascular arrangement, as in hyperlipoproteinemic xanthomatosis. We concluded that ultrastructural aspects of different xanthomatosis are fairly similar as a consequence of the large amount of intracytoplasmic lipids accumulated in xanthomatous cells. In xanthelasma palpebrarum and in disseminated plane xanthoma this cell phase is reached by similar pathways to those for hyperlipoproteinemic xanthomatosis, whilst in xanthoma disseminatum and juvenile xanthogranuloma the pathways seem to be different. A classification of normolipidemic xanthomatosis is also provided.
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  • 53
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    Protoplasma 100 (1979), S. 73-83 
    ISSN: 1615-6102
    Keywords: Bivalve ; Fertilization ; Laternula limicola ; Sperm-egg interaction ; Temporary-acrosome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural studies on sperm-egg interaction at the time of fertilization inLaternula limicola were performed. The “temporary-acrosome” did not change morphologically while the sperm passed through the egg investments. At the onset of sperm entrance into the egg, however, the temporary-acrosome and mitochondria were eliminated from the sperm. Afterwards the sperm was engulfed by the egg surface without membrane fusion of the gametes. After entry the sperm nucleus was surrounded by four membranes: the plasma membranes of the egg and of the sperm, and the membranes of the sperm nuclear envelope. As the sperm nucleus differentiated into the male pronucleus, the plasma membranes of both the sperm and egg were initially vesiculated, then dispersed into the egg cytoplasm. Finally, the sperm nuclear envelope changed into the male pronuclear membrane accompanying sperm chromatin dispersion.
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  • 54
    ISSN: 1615-6102
    Keywords: Mating ; Sporidia ; Tilletia ; Ultrastructure ; Wheat bunt
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Primary sporidia ofTilletia caries (DC.) Tul. are borne on denticles at the tips of promycelia. The promycelia contain many small vacuoles and mitochondria and numerous lipid bodies. As the primary sporidia develop, the promycelial cytoplasm passes into the nascent cells. Septa develop between the bases of mature sporidia and the tips of the denticles. Sporidia that abscise from the denticles commonly have prominent birth scars at their bases. The sporidia have very thin walls, few vacuoles, attenuated mitochondria, and numerous lipid bodies. Conjugation pegs are generally produced by both members of a conjugating pair of sporidia and there are bud scars where they emerge from the sporidia. The sporidial walls are apparently hydrolyzed during emergence of the pegs. Vesicles are sometimes present at the tips of the conjugation pegs and, before fusion, electron-dense accumulations are sometimes observed between the tips of adjacent pegs. The approaching conjugation pegs are precisely aligned prior to fusion, suggesting polar communication. The walls of the conjugation pegs fuse and then are hydrolyzed. Fused sporidia are relatively homogeneous in content. The nucleus in a sporidum is often close to the conjugation tube and occasionally is partly within the fusion tube.
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  • 55
    ISSN: 1615-6102
    Keywords: Amoeba proteus ; Anaerobiosis ; Metabolic inhibitors ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Anaerobiosis or exposure to the metabolic inhibitors potassium cyanide and Antimycin A produced changes in the form of living amoebae. These were accompanied by mitochondrial changes in fixed cells. Increasing the anaerobic period increased the percentage of mitochondria affected and resulted in a gradual reduction and eventual loss of the condensed Type I mitochondria ofAmoeba proteus. The rounder Type II mitochondria were not lost but underwent varying degrees of disruption, vesiculation of the cristae being evident after 5 hours exposures and matrical inclusions after 18 hours exposures. Similar cristal vesiculation was seen after 30 minutes treatments with potassium cyanide. Providing treatments were terminated before cell viability was lost, all mitochondrial abnormalities were reversible on return to normal culturing conditions. The longer the period of anaerobiosis the longer was the recovery time required for the return of normal mitochondrial structure and the re-equilibration of control Type I to Type II mitochondrial frequencies. The relationship between mitochondrial conformation and functional integrity is discussed in the light of these findings.
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  • 56
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    Cell & tissue research 200 (1979), S. 257-271 
    ISSN: 1432-0878
    Keywords: Anococcygeus muscle ; Innervation ; P-type nerves ; Purinergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the rat anococcygeus muscle has been investigated ultrastructurally following fixation with a modified chromaffin reaction for the demonstration of biogenic amines (Tranzer and Richards, 1976). Three types of nerve profiles were revealed: (1) 60–70 % of the profiles are adrenergic; (2) less than 5% of the profiles appear to be cholinergic; (3) up to 40% of the profiles are distinguished by the presence of a characteristically high proportion of electron-opaque, chromaffin-negative vesicles, 85–110nm in diameter. This third type of profile was not affected by 6-OHDA, and is considered to represent the non-adrenergic, non-cholinergic inhibitory innervation of this tissue. Because of the morphological similarity of this nerve type, apart from the smaller vesicle size, to classical peptidergic nerve endings, they have been termed “small p-type” (sp-type). These results are discussed in relation to a previous report describing only two types of nerve profiles in this tissue (Gillespie and Lüllmann-Rauch, 1974).
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  • 57
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    Cell & tissue research 200 (1979), S. 291-298 
    ISSN: 1432-0878
    Keywords: Excitatory synapse ; Lateral line-canal organ ; Synaptic body ; Ultrastructure ; Lota lota (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the afferent synapse in hair cells of the lateral line-canal organ was studied using different fixation and staining techniques. Glutaraldehyde-fixed tissue without post-osmication, contrasted by section staining with uranyl acetate and lead citrate, was compared with (a) osmium tetroxide-fixed tissue followed by the same staining procedure, and with (b) glutaraldehyde-fixed tissue, block-impregnated with phosphotungstic acid (PTA). The results reveal a pronounced heterogeneity in the composition of the synaptic body, reflecting regional differences in chemical affinity to the fixatives and staining agents. It is proposed that the “intracleft substance”, the synaptic structure defined by the PTA staining technique, is actually due to the glutaraldehyde fixation procedure and is apparently the outer leaflet of the postsynaptic membrane. A special technique that allows alternate sections of a series to be differentially stained for electron microscopy is proposed.
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  • 58
    ISSN: 1432-0878
    Keywords: Liver ; Goldfish ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A re-examination of goldfish liver was made through the use of SEM of fractured samples and TEM of ultrathin-sections and freeze-etch replicas. Several new hepatic fine structures described in the present study are morphologically similar to those reported previously in many higher vertebrates including mammals. Hepatic sinusoids of goldfish contain fenestrations which are arranged into sieve plates. Although the hepatic plates are made up of two layers of hepatocytes, the parenchymal cells of goldfish liver are morphologically similar to mammalian hepatocytes, particularly with respect to the sinusoidal surfaces which are studded with numerous microvilli. The intercellular surfaces of hepatocytes have both nexus and desmosomal junctions, similar to those found in various epithelial cells of higher vertebrates, as cell attachments and communication foci. Tight junctions are found mainly between the openings of the intracellular bile canaliculi and the intralobular bile ductules which are situated in the center of the bicellular hepatic plate.
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  • 59
    ISSN: 1432-0878
    Keywords: Adrenal medulla (rat) ; Vinblastine ; Ultrastructure ; Catecholamines ; Enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a single high dose (10mg/kg) of vinblastine (vb) sulfate (“Velbe”, Lilly) on the ultrastructure, catecholamine (CA) content and activity of CA-synthesizing enzymes of the rat adrenal medulla were studied for up to 120h after intravenous injection of the drug. By 1 h, microtubules were virtually absent from chromaffin cells and preganglionic cholinergic axons, and typical paracrystals had appeared inside the nerve fibers. By 16h microtubules were completely reconstituted and paracrystals had disappeared. From 16h onwards, there was an increasing depletion of storage granules from adrenaline (A) — producing cells, which coincided with biochemical determinations showing a reduction of adrenal A to about 40 % of control levels by 48 h, with noradrenaline (NA) remaining in the range of controls. Both A- and NA-storing cells showed an extensive proliferation of the rough endoplasmic reticulum (ER). Vb caused a marked increase in tyrosine hydroxylase (TH; +113%) and dopamine β-hydroxylase (DBH; +82%) activities after 48 h. Splanchnicotomy completely abolished the vb-mediated increase in TH and DBH activities. A smaller increase (+ 47 %) in enzyme activity was observed with phenylethanolamine N-methyltransferase (PNMT). Vb (10−5M) had no apparent effect on granule content and the amount of rough ER in chromaffin cells, which were cultured for 48 h. The results demonstrate that a single high dose of vb has relatively little short-term effects on the rat adrenal medulla, but causes drastic long-term changes in CA-content and enzyme activities that are mediated by the preganglionic nerves. These changes could be interpreted as an effort to compensate for a loss of CA-stores in peripheral adrenergic nerves (cf. Cheney et al., 1973). The differential long-term effect of vb on adrenal NA and A might be due to the lower induction of PNMT as compared to TH and DBH activities and/or to a preferential release of A versus NA, which may occur at high frequencies of stimulation of the splanchnic nerves.
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  • 60
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    Cell & tissue research 196 (1979), S. 289-306 
    ISSN: 1432-0878
    Keywords: Spleen ; Carp ; Sheathed capillaries ; Macrophages ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the spleen of the carp arterial capillaries of a highly differentiated structure have been studied by light and electron microscopy. These capillaries share various structural characteristics with the sheathed capillaries (ellipsoids of Schweigger-Seidel) of higher vertebrates. The long arterial capillaries of the carp spleen are provided with cuboidal endothelial cells containing filaments approximately 7 nm in diameter. There is no basal lamina. The endothelial cells form various types of cell junctions, but there are also extensive areas without any junctions. Here, a free passage is possible between the capillary lumen and the subendothelial space. The capillaries possess a single-layered sheath of macrophages. Characteristically, the sheath macrophages possess long and slender cell processes forming a loose framework, the meshes of which are filled with lymphocytes and spindle cells. The sheath macrophages show a zone of ectoplasm rich in filaments. They also contain numerous phagolysosomes rich in hydrolytic enzymes, as identified histochemically. The sheath is sharply limited against the pulp by a thick layer of collagen fibers.
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  • 61
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    Cell & tissue research 197 (1979), S. 105-112 
    ISSN: 1432-0878
    Keywords: Thymus ; Myoid cells ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical and ultrastructural properties of myoid cells in the thymus of the frog were investigated and compared with properties of skeletal muscle fibres. The histochemical reactions of phospholipids, phosphorylase, succinic dehydrogenase and adenosine triphosphatase activities in myoid cells were characterized by considerable variability. Individual myoid cells apparently possess different enzyme activities which correspond to different stages of development, maturity and degeneration of these cells. The mature mononucleated myoid cells have similar enzymatic properties to the fast muscle fibres of the frog. This finding has been extended by ultrastructural observations. Features, typical of fast muscle fibres of the frog, e.g. the presence of the M-line, straight and narrow Z-line and well developed triads were found in the majority of mature myoid cells.
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  • 62
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    Cell & tissue research 197 (1979), S. 113-135 
    ISSN: 1432-0878
    Keywords: Domestic fowl ; Ultimobranchial gland ; Parathyroid gland ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the polymorphic vesicular component of the ultimobranchial gland of the domestic fowl (Gallus gallus domesticus) has been described in detail, together with the structure of the cell strands interconnecting the vesicles and the parathyroid nodules lying within the ultimobranchial stroma. The vesicles frequently appear to arise from the nodules by way of the cell strands. The strands show a structure of their component cells intermediate between that of the parathyroid and the vesicular cells, although the position at which the strand changes from an essentially parathyroid structure to an essentially vesicular structure is very variable. The degree and kind of secretory activity within different cell types has been described. A review of the structure of ultimobranchial glands throughout the vertebrates shows that similar tissue with a similar secretory potential has been observed in all vertebrate classes, suggesting a functional significance for this part of the gland.
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  • 63
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    Cell & tissue research 198 (1979), S. 373-380 
    ISSN: 1432-0878
    Keywords: Ventral cochlear nucleus ; Calyceal processes ; Flattened synaptic vesicles ; Ultrastructure ; Morphometric study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In this paper we report the appearance of flat vesicle-containing endings in aldehyde-fixed ventral cochlear nucleus of rats with qualitative and quantitative properties suggesting they should be identified as calyceal processes. Their synaptic vesicles are elongate and significantly smaller than the vesicles in the calyces of Lenn and Reese (1966). Therefore these endings are flat vesicular calyceal processes, possibly of inhibitory function.
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  • 64
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    Cell & tissue research 198 (1979), S. 411-426 
    ISSN: 1432-0878
    Keywords: Intermediate lobe ; Hypophysis ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the intermediate lobe of the hypophysis was studied in Anolis carolinensis with the use of a threefold aldehyde fixative. Lizards with a brown skin were selected. The possibility of two types of secretory cells is discussed; neither cell type is innervated. Type I cells are rarely found and contain dense granules approximately 0.3 μm in diameter; Type II cells vary widely in secretory activity. Most of the Type II cells contain a large number of dense secretory granules (up to about 1.3 μm in diameter) almost filling the cytoplasm. Rough endoplasmic reticulum (RER), Golgi apparatus and mitochondria are poorly developed. Only some of these cells show signs suggesting a high secretory activity, namely a well developed RER, Golgi apparatus and numerous mitochondria. In these cells the RER sometimes forms large intracisternal droplets (up to 7 μm in diameter). Two of the animals exhibited a more uniform, high secretory activity. Large (about 2 μm in diameter), pale vacuoles, probably of extracellular character, were found mostly in the vicinity of the perivascular septum. Their role in the release of MSH is discussed. The present data, which are discussed with reference to earlier findings (Forbes, 1972), form the morphological basis for an experimental study on regulation of MSH release (Larsson et al., 1979).
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    Cell & tissue research 198 (1979), S. 455-463 
    ISSN: 1432-0878
    Keywords: Neuromuscular synapses ; Presynaptic density ; Ultrastructure ; Serial sections ; Crustaceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Representative examples of lowand high-output neuromuscular synapses between motoneuron and distal accessory flexor muscle of the lobster were selected on the basis of their mean quantal content, and subsequently analysed by serial section electron microscopy. The high-output terminal has twice as many synapses as the low-output terminal. However, since the mean surface area of synapses is significantly smaller in the high-output terminal than in the low-output one, the total synaptic surface area between the two types of terminals is similar. Also, though the high-output terminal possesses a greater number of presynaptic dense bodies than its low-output counterpart, the mean number per synapse is similar for the two terminals. The terminals, however, differ significantly in the size of their dense bodies. Thus both the mean and total surface area of these bodies is greater in the high-output terminal than in the low-output one. Moreover, the mean ratio of dense body area to synaptic area is significantly greater for the high-output terminal than for its low-output counterpart. This difference in dense body area parallels the difference in quantal content of synaptic transmission between the lowand high-output terminals and supports the hypothesis that presynaptic densities represent the ultrastructural correlates of transmitter mobilization and/or release.
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  • 66
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    Cell & tissue research 199 (1979), S. 373-386 
    ISSN: 1432-0878
    Keywords: Hypogastric ganglion (rat) ; Vacuolated neurons ; Catecholamine fluorophore ; Ultrastructure ; Testosterone ; Castration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vacuolated neurons (VN) of the main hypogastric ganglion of the male rat were studied using the formaldehyde-induced fluorescence (FIF) method for the histochemical demonstration of catecholamines. Microspectrofluorimetry was performed to identify the fluorophores and to quantify the FIF. The thiocholine method (Koelle-Gomori) was used to demonstrate acetylcholinesterase activity. The fine structure of the VN was studied using glutaraldehyde/OsO4 fixation. (1) In the untreated adult male rat VN represent only a small population of the total number of hypogastric neurons (0.8–1.2%). The vacuoles are similar to those of the VN from the corresponding female ganglion. (2) The VN are considered to be adrenergic due to the nature of their fluorophore, indicating a primary catecholamine. (3) The first VN appear in the hypogastric ganglia at the age of 7 weeks. After testosterone administration to young rats, VN are found at the age of 4 weeks. (4) The basic fine structure of the VN is similar to that of other ordinary neurons of the hypogastric ganglia. (5) The content of the vacuoles could not be identified. (6) Indications of degeneration were not observed in the VN. (7) The VN are interpreted as being a functional stage of the “short” adrenergic neurons, which are under the control of steroid hormones. (8) Fifteen months after castration, no VN could be found in the hypogastric ganglia, while their number was normal in the corresponding control animals.
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  • 67
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    Cell & tissue research 199 (1979), S. 483-492 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; Luteotroph cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars distalis of the rat. The animals received 100μg/100 g pimozide daily for 5, 10, 15, and 20 days. Pimozide induces striking ultrastructural changes after 5 days of treatment. The number of luteotroph (LTH) cells is significantly increased; they display characteristics of stimulation. The extrusion of granules into the intercellular space via exocytosis is frequently observed. The intercellular spaces are highly dilated, forming a lacunar system filled with an amorphous material, erythrocytes and involuted LTH cells. Transitional stages in the process of involution are observed in LTH cells. Luteotroph cells also form a syncytium. Twenty days after treatment the abovedescribed changes decrease in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in the luteotroph cells, an effect that is less evident with longer treatment.
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  • 68
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    Cell & tissue research 199 (1979), S. 519-528 
    ISSN: 1432-0878
    Keywords: Filum terminale ; Spinal cord ; Glial cells ; Ultrastructure ; Frog (Rana pipiens)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The filum terminale, or terminal portion of the spinal cord, was studied in normal adult frogs (Rana pipiens) by means of light and electron microscopy. Astroglial cells are the predominant elements in this region. The rostral portion of the filum terminale consists mainly of (1) a peripheral dense ring of myelinated and some unmyelinated nerve fibers, and processes of astrocytes terminating at the subpial space; (2) an intermediate zone, in which astrocytes are the main cellular elements in addition to a few degenerated neurons; and (3) a central region where the central canal is lined by dark and light ependymal cells. In the caudal portion of the filum terminale, the amount of neuropil is greatly reduced. This region is formed mainly by astrocytic glial cells and very few neuronal elements. The central canal in the caudal portion is located ventrally and contains a lining consisting almost exclusively of dark ependymal cells.
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  • 69
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    Keywords: Pars distalis ; Graft ; Ultrastructure ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intact female rats received transplants of two hypophysial partes distales under the kidney capsule. The plasma levels of prolactin were determined, and the ultrastructure of the grafted gland was studied 15, 45 and 90 days after the operation. Although prolactin levels in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in the 45-day samples. Parallel ultrastructural changes suggest that between the 45th and 90th postoperative day a process is initiated leading to hyperplasia and hypertrophy of prolactotrophs.
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  • 70
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    Cell & tissue research 201 (1979), S. 369-376 
    ISSN: 1432-0878
    Keywords: Leydig cells ; Filaments ; Golden hamster ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A unique cytoplasmic structure has been observed in Leydig cells of the golden hamster. It consists of a laminar core made up of electron dense material surrounded by a filamentous matrix of lower density, and is tentatively called a dense-cored filamentous body (DCFB). DCFBs vary in overall size and in configuration of the centrally disposed dense lamina. They are typically located in the vicinity of the centrosome and the Golgi complex. The body has no limiting membrane, and may be in contact with virtually every type of organelle. The DCFB is well developed in active Leydig cells, whereas it is small in the quiescent stage of the secretory cell. It is likely that the DCFB is a constant organelle in the hamster Leydig cell and may be involved in the physiological function of the Leydig cell, which remains to be specified.
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  • 71
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    Cell & tissue research 202 (1979), S. 145-153 
    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Ultrastructure ; Symphyla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired ovaries of Symphyla are sac-shaped. Their interior is filled with synchronously developing oocytes surrounded by a simple follicular epithelium. Previtellogenic oocytes have spherical or oval nuclei, the latter containing a large number of small nucleoli. Part of the nuclear surface is covered by a thick “coat” made up of a granular substance of medium electron density. The “coat” is penetrated by cisternae of the smooth endoplasmic reticulum. Micropinocytosis is the principal source of yolk in Symphyla; a small amount of yolk material arises within the mitochondrial cristae. Vitellogenic oocytes are characterized by a highly active rough endoplasmic reticulum synthesizing a material, probably lipoprotein in nature, which is incorporated into lipid droplets.
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  • 72
    ISSN: 1432-0878
    Keywords: Pancreatic endocrine cells ; Enteroendocrine cells ; Ultrastructure ; Cyprinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic endocrine cells of Barbus conchonius are concentrated in a large (principal) islet, located near the gall bladder, and in a number of smaller islets. Five types of endocrine cells can be distinguished in these pancreatic islets: B cells, A1 (or D cells), 2 types of A2 cells (A2r cells with round granules; and A2fl cells with flocculent granules) and a scarce 5th cell type. The hormones produced by B and A2fl cells are probably insulin and glucagon respectively. The A2r cell contains granules with the same diameter as the granules of the enteroendocrine type III cell of the gut. Both cell types may resemble the enteroglucagon-producing EG cell of mammals. The function of the A1 cells, which are frequently found without secretory granules, and of the 5th cell type, will be discussed. The pancreatic islets of B. conchonius are strongly innervated, which suggests the presence of a direct nervous control system. Some intermediate or mixed cells containing exocrine and endocrine A2r granules are found contiguous with the principal islet. The origin of pancreatic endocrine cells is also the subject of discussion.
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  • 73
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    Cell & tissue research 202 (1979), S. 431-438 
    ISSN: 1432-0878
    Keywords: Sturgeon ; Heart ; Ultrastructure ; Sarcoplasmic reticulum ; Granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of atrial and ventricular myocardial cells from Acipenser stellatus is described. The cells of the atrium are more loosely connected than those of the ventricle. Cell contact is by simple intercalated discs and by desmosomes. The cells are flattened, with peripheral myofibrils and a central region of mitochondria and the nucleus. The sarcoplasmic reticulum consists of subsarcolemmal tubules, that frequently extend towards the central mitochondria. Dyads are small and positioned at any sarcomeric level. No T-tubules are present. Specific granules are restricted to the atrial cell, and are sometimes present within the SR tubules.
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  • 74
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    Cell & tissue research 200 (1979), S. 299-309 
    ISSN: 1432-0878
    Keywords: Germ-free mice ; Inflammation ; Macrophages ; Peritoneum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peritoneal macrophage ultrastructure was analysed stereologically in germ-free mice given a single intraperitoneal injection of sterile, pyrogen-free saline. Thus the stimulant was non-particulate, non-antigenic and inorganic, and effects of immune reactions were minimal. Macrophages were recovered 1, 6, 24 and 72 h after stimulation. A sequence of structural alterations is reported which may be fundamental to macrophage activation. The plasma membrane and nuclear envelope increased in area within only 1 h of saline injection. During the next 5 h loss of plasma membrane, probably by pinocytosis, caused cellular “rounding” and clear-cut alteration in surface configuration. At the same time lysosome-like granules enlarged but decreased in number. By 24 h most cellular structures and compartments (including the plasma membrane) were enlarged. Morphological evidence of nuclear activation accompanied a rather modest enlargement of the nucleus at this stage. The RER hypertrophied last and must, therefore, be judged sufficient in resident macrophages to support the initial growth response which results after stimulation. Thus hypertrophy was observed eventually in every structure examined. Even the minimally activated macrophages resident in the peritoneum of germ-free mice respond readily to stimulation.
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  • 75
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    Cell & tissue research 196 (1979), S. 449-454 
    ISSN: 1432-0878
    Keywords: Gastric epithelium (Rat) ; Phagocytosis ; Cell loss ; Aspirin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gastric surface epithelial cells (SEC) from fed rats, from rats fasted for 16 h and from mucosae exposed in an ex-vivo chamber to 16 mM aspirin for 5 min were examined by transmission electron microscopy. SEC have the capability to phagocytose adjacent epithelial cells and parietal cells. Phagocytosis is rare in mucosae from fasted animals but common in fed animals or after brief exposure to aspirin. Phagocytic capabilities are not restricted to the progenitor zone but exist throughout the surface epithelium. Phagocytosis may provide a mechanism for the removal of damaged or senescent cells from the surface epithelium.
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  • 76
    ISSN: 1432-0878
    Keywords: Interrenal tissue (birds) ; Ultrastructure ; Corticotropin ; Adenohypophysectomy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adrenal glands from ACTH-treated intact ducks and chronically adenohypophysectomized ducks showed clear zonation into a subcapsular zone (SCZ) and an inner zone (IZ). Adenohypophysectomy caused ultrastructural changes in the IZ but not in the SCZ cells. These included increases in lipid droplets, changes in mitochondrial cristae from tubular to shelf-like, and changes in the shape of the nuclei from spherical to crenated. These changes were reversed by treatment with ACTH. Also, cells of the IZ, but not the SCZ, of adrenals from intact birds given ACTH showed more SER, more dense bodies, fewer lipid droplets and more prominent Golgi complexes. IZ cells incubated in buffer containing no ACTH developed mitochondria with shelf-like cristae and numerous opaque granules in the matrix. Exposure to buffer containing ACTH caused the mitochondrial cristae to become tubular and the matrix granules either decreased in number or disappeared. The granules could be extracted by incubating sections with chelating agents. The mitochondria in SCZ cells did not respond structurally to the presence of ACTH in the incubation medium but the matrix granules, like those in IZ cells, responded to the presence of chelating agents.
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  • 77
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    Cell & tissue research 196 (1979), S. 531-539 
    ISSN: 1432-0878
    Keywords: Fiber types ; Red muscle ; Semitendinosus muscle ; Ultrastructure ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The semitendinosus muscle of the rabbit is composed of a homogeneous fiber population. Fiber typing was carried out by means of light and electron microscopy according to which this muscle exhibits structural features that are either characteristic for both ‘red’ and ‘white’ fibers, or that do not allow for any classification according to the A-, B-, C-fiber system. Hence the long-held assumption that the semitendinosus muscle of the rabbit represents a classical paradigm of a ‘red’ muscle should be revised in light of the present results.
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  • 78
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    Cell & tissue research 197 (1979), S. 165-167 
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Chick embryo ; Muscular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary New Hampshire chickens, homozygous for inherited muscular dystrophy, display clinical manifestations at an early age. A fine structural examination of embryos from this strain shows marked degenerative changes four days prior to hatching. The Z bands appear to dissolve progressively to the point where finally the myofibrils become uniformly dense with no detectable banding patterns.
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  • 79
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    Cell & tissue research 198 (1979), S. 191-199 
    ISSN: 1432-0878
    Keywords: Spermatogonia ; Man ; Stem cells ; Morphology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present investigation is concerned with establishing morphological criteria of spermatogonial stem cells in man. Testicular biopsies from patients having undergone semicastration for malignant tumors and radioand chemotherapy for one year following the operation were studied light and electron microscopically. Those spermatogonial types that survived the treatment were regarded as stem cells in view of the fact that the stem cells, in contrast to the more differentiated spermatogonia, are radiation resistant and less sensitive to various noxious agents. In 7 out of 28 cases examined, a small number of spermatogonia was found adjacent to the basement membrane. The majority of these cells show the characteristic features of pale type A spermatogonia, while a few cells may represent variants of this cell type. The dark type A spermatogonia are almost completely eliminated from the seminiferous tubules. A concept is proposed that the stem cells of the human testis may be derived from the pale type A spermatogonia or the variants of this cell type.
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  • 80
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    Keywords: Haemocytes ; Phagocytosis ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.
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  • 81
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    Cell & tissue research 199 (1979), S. 249-256 
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Birds ; Ultrastructure ; Estrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Administration of estradiol-17-β induces the synthesis of vitellogenin in primary cultures of chick embryo liver. The ultrastructural changes accompanying steroid induced vitellogenin synthesis were investigated in hepatocytes cultures incubated for 0, 12 and 24 h following hormonal treatment. Both electron microscopy and immuno-chemical techniques were used. The immuno-fluorescence data indicate that the cultures contain a cell population of 90–95% hepatocytes, both in control and estradiol-treated groups. Ultrastructurally, cultured hepatocytes are similar to in vivo ones, except for a reduced accumulation of storage materials, glycogen and lipids. In the estradiol-treated cultures hepatocytes show an accumulation of free ribosomes, enlargement of rough endoplasmic reticulum, and development of the Golgi apparatus. The data are discussed in relation to previous biochemical findings.
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  • 82
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    Cell & tissue research 202 (1979), S. 33-39 
    ISSN: 1432-0878
    Keywords: Gregarina ; Ultrastructure ; Gram negative bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An investigation of bacteria-like structures, which are found in large numbers in the endoplasm of the eugregarine, Gregarina garnhami, was carried out using light and electron microscopy. Gram staining indicates that these structures are gram negative; they show orange fluorescence when stained with acridine orange. Ultrastructural observations show that they resemble the endosymbiotic bacteria found in other protozoan species. Some of these structures appear to be dividing, and the possibility that these structures are in fact bacteria is discussed.
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  • 83
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    Cell & tissue research 203 (1979), S. 427-442 
    ISSN: 1432-0878
    Keywords: Aphids ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopical study was made of the coeloconic and placoid sensilla on the antennae of the aphids Aphis pomi, Macrosiphum euphorbiae, Nasonovia ribis-nigri, and Pemphigus bursarius. Scanning electron microscopy revealed some variation in morphology which may be functionally important but is more likely to reflect the evolution of these species. The placoid sensilla were shown by transmission electron microscopy to have the same basic structural pattern. Each group of two or three neurons is surrounded by two ensheathing cells. The ciliary regions of the dendrites pass through a vacuole into a cavity between an outer and an inner cuticle where they may be connected to the dendritic branches although such connections were not seen. Small pores (8 nm diameter) partially penetrate the cuticle implying that these sensilla have an olfactory function. They are suggested to be important in host selection by alate aphids. The coeloconic sensilla are poreless pegs with nonsensory cuticular projections at their tips. The distal portions of their dendrites contain densely packed microtubules and the cellular arrangement of the sensilla is similar to that of the placoid sensilla. It is suggested that they may function as thermoreceptors.
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  • 84
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    Cell & tissue research 203 (1979), S. 503-506 
    ISSN: 1432-0878
    Keywords: Muscle ; Disuse atrophy ; Insects ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The changes which occur in the ultrastructure of the mesothoracic retractor unguis muscle of the cockroach Periplaneta americana as a result of disuse are described. Breakdown of myofibrils, sarcoplasmic reticulum, and mitochondria are all marked, this degeneration only being apparent 9 weeks after the operation.
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  • 85
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    Cell & tissue research 204 (1979), S. 233-241 
    ISSN: 1432-0878
    Keywords: Merkel cell ; Sensory receptors ; Epidermis ; Frog tadpoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy of larval tentacles of Xenopus laevis tadpoles revealed that they are richly innervated structures containing a high concentration of neurite complexes with epidermal Merkel cells. Myelinated sensory nerve fibres supplying each tentacle are abundant. Prior to penetrating the epidermis, they gradually shed their myelin sheaths and Schwann-cell coverings, and subsequently end as naked axon terminals within the epidermis. Many of these intra-epidermal neurites terminate in intimate synaptic contact with granulated Merkel cells. Groups of dense-cored vesicles characterize the Merkel cell, while clusters of clear synaptic vesicles occupy the adjacent sensory nerve terminals. At sites of synaptic contact, the two cells often exhibit an increased thickening of their apposing membranes. Such Merkel cell — sensory neurite complexes occur as isolated units and are profusely scattered throughout the extent of each tentacle. Their ultrastructure is, in most respects, similar to that described previously in specialized regions of other vertebrate and amphibian species. It is suggested that they represent the morphological basis for tactile sensitivity and impart a mechanoreceptive function to the larval tentacle prior to metamorphosis. The larval tentacle in this anuran species may represent a new and convenient research model for future developmental and experimental studies of trophic interactions between sensory nerve fibres and Merkel cells.
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  • 86
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    Cell & tissue research 202 (1979), S. 453-460 
    ISSN: 1432-0878
    Keywords: Collagen ; Nerves ; Ganglia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Nerves and ganglia from a variety of fish, amphibian, reptilian and mammalian species were studied by optical and electron microscopy. Observations using the Picrosirius-polarization method strongly suggest that two different types of collagen fibers are present in the connective tissues of nerves and ganglia. Electron microscopy of nerves and ganglia showed the presence of two different collagen fibril populations, distinguishable on the basis of diameter, located in different compartments of these structures. Thicker fibrils are present in nerve and ganglionic epineurium. Thinner fibrils are present in the endoneurium, surrounding nerve fibers and ganglionic cells, and between the concentric layers of perineurial cells. These results were consistently observed in all species studied and very probably represent a general phenomenon in vertebrates.
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  • 87
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    Cell & tissue research 202 (1979), S. 479-491 
    ISSN: 1432-0878
    Keywords: Ependyma ; Ultrastructure ; Posterior tela choroidea ; Rhombencephalon ; Rana catesbeiana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The posterior rhombencephalic tela choroidea of the bullfrog was examined by electron microscopy. This membrane, the pia-ependymal roof of the caudal hindbrain, contains a large central region characterized by cuboidal ependymal cells which surround sizable microscopic apertures — the interependymal pores. Ultrastructurally ependymal cells of this area are characterized by infrequent apical microvilli and cilia. They contain irregularly shaped nuclei and few cytoplasmic organelles that are largely apical in position. The most striking feature is an abundance of cytoplasmic filaments forming an extensive cytoskeleton. Laterally these cells are joined by numerous elaborate desmosomes. The majority of the ependymal cells have a basal lamina consisting of single, double, or triple laminae lying parallel to the basal plasma membrane. Several unusual specializations are seen at the margins of the interependymal pores. The ependymal cells have lateral cytoplasmic processes that form the actual border of each pore. These processes originate from the apical surface of the cell and partially enclose an elaborate network of basal lamina associated with the interependymal pores. These findings demonstrate microscopic apertures in the roof of the fourth ventricle in the bullfrog that are associated with an unusual form of supportive ependyma.
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  • 88
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    Cell & tissue research 203 (1979), S. 311-320 
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Acipenseridae ; Ultrastructure ; Quantitative analysis ; Spawning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The percentage of peptidergic (A1 and A2) and adrenergic (B) neurosecretory terminals was studied in the neurohypophysis of sexually mature female sturgeons. Neurosecretory terminals of the A2 type prevail in the neurohypophysis, whereas A1 and B terminals are rare. The activity of these types of terminals was established (1) during upstream migration, (2) shortly after spawning, and (3) three to six weeks after spawning. Terminals of B type are the most active elements during all the periods studied. These elements become strongly activated in sturgeons during upstream migration, i.e., earlier than the peptidergic neurosecretory terminals. Peptidergic terminals, especially elements of type A2, become synchronously and strongly activated in fish shortly after spawning. In the late postspawning period neurosecretory terminals of all three types become synchronously inactive, persisting in a quiescent state in comparison to the two previous periods. The appearance of neurosecretory material discharged into the intercellular clefts by exocytosis correlates on the whole with the activity level of the A1 and A2 terminals in each individual studied. A functional correlation exists between the activity of the peptidergic and adrenergic neurosecretory terminals in the neurohypophysis. The data obtained are discussed with reference to a concept regarding spawning in some fish species as a physiological stress (Polenov et al., 1976). A possible dual control (peptide and monoamine neurohormones) over the function of visceral organs and glandular cells of the intermediate lobe of the hypophysis is also suggested (Polenov, 1970, 1975, 1978; Polenov and Belenky, 1973).
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  • 89
    ISSN: 1432-0878
    Keywords: Pineal gland ; Ultrastructure ; Cotton rat (Sigmodon hispidus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Fine structural features of pinealocytes of cotton rats (Sigmodon hispidus) were examined. Golgi complexes, mitochondria, endoplasmic reticulum and polysomes are usual organelles seen in the perikaryonal cytoplasm of pinealocytes. Many non-granulated vesicles (40 to 80 nm in diameter) and a few granulated vesicles (about 100 nm in diameter) are associated with the Golgi cisternae. Occasionally, the cisternae contain granular materials. The perikaryonal cytoplasm of pinealocytes is characterized by the presence of inclusion bodies. These bodies are usually round in shape, not bounded by a limiting membrane and composed of fine granular or filamentous materials of high electron-opacity, which are similar in appearance to the substance seen in the nucleolonema. Pinealocyte processes, filled with abundant non-granulated vesicles and some granulated vesicles, are mainly found within the parenchyma and occasionally in perivascular spaces.
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  • 90
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    Keywords: Thyroid follicular cells ; Basal lamina, biosynthesis ; Cellular interaction ; Cell culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Porcine thyroid cells were cultured alone or in mixed cultures with mesenchymal cells. The formation of a basal lamina in vitro was investigated ultrastructurally. Follicular reassociation of thyroid cells occurred in both types of culture; however, it was followed by formation of the basal lamina only when mesenchymal cells were present. The present findings suggest an epithelial origin of the basal lamina resulting from an interaction with mesenchymal cells.
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  • 91
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    Cell & tissue research 200 (1979), S. 193-203 
    ISSN: 1432-0878
    Keywords: Mosquitoes ; Midgut ; Ultrastructure ; Stereology ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Morphometrische Untersuchungen des Magenepithels von A. aegypti weisen darauf hin, daß die Verdauung des ersten Blutmahls in eine Reihe von Phasen gegliedert werden kann, die sich mit physiologischen Daten aus der Literatur korrelieren lassen. In einer Phase Ia (0–10 h nach Blutmahl [BM]) entfalten sich die “whorls” des rauhen endoplasmatischen Retikulums, die Golgi-Zonen werden größer, und das basale Labyrinth wird erweitert. Dies stimmt mit Synthese- und Sekretionsprozessen (z.B. peritrophische Membran, Esterasen, Lipasen) und mit Transportvorgängen durch das Magenepithel überein. In Phase Ib (10–20 h nach BM) nehmen die gemessenen zellulären Parameter weiter zu und weisen damit auf hohe Synthese- und Sekretionsaktivitäten (z.B. Verdauungsenzyme) hin. In Phase Ic (20–30 h nach BM) zeigen die an Synthese und Sekretion beteiligten Zellstrukturen, in Übereinstimmung mit der maximalen Proteasenaktivität im Darm, immer noch hohe Werte. Vergrößerte Mikrovillioberfläche, auffallende Lipideinschlüsse und Auftreten von Glykogendepots im Magenepithel deuten auf erhöhte Resorptions-, Speicher- und Transportfunktionen der Zellen hin. In Phase II (30–36 h nach BM) läßt sich anhand der strukturellen Veränderungen der Wechsel von Synthese- und Sekretionvorgängen zu Resorption, teilweiser Speicherung und Transport von Verdauungsprodukten erkennen. In Phase III (36–72 h nach BM) wird der Zellapparat in Übereinstimmung mit dem Ende der Verdauung reduziert. Lipid- und Glykogendepots werden mobilisiert und verschwinden fast vollständig aus den Magenepithelzellen.
    Notes: Summary Morphometric analysis of the epithelial lining of the stomach of A. aegypti suggests that digestion of the first blood meal in the stomach of this species can be viewed as a series of phases that can be correlated with physiological data from the literature. In phase Ia (0–10 h after blood meal [abm]) the whorls of the rough endoplasmic reticulum unfold, the Golgi zones increase, and the basal labyrinth is enlarged. This coincides with processes of synthesis and secretion (e.g., peritrophic membrane, esterases and lipases) and transport by the stomach epithelium. In phase Ib (10–20 habm) the cellular parameters measured further increase, indicating high synthetic and secretory activities (e.g., digestive enzymes). In phase Ic (20–30 habm) cell structures involved in synthesis and secretion still exhibit high values coinciding with maximal activity of proteases in the gut. Enhanced surface area of microvilli, prominent lipid inclusions, and appearance of glycogen deposits in the gut epithelium suggest increased absorption, storage, and transport functions of the stomach cells. In phase II (30–36 habm) structural alteration points to a gradual shift from synthesis and secretion to absorption, partial storage, and transport of nutrients. In phase III (36–72 habm) the cellular apparatus is reduced concomitant with the ending of the digestive cycle. Lipid inclusions and glycogen deposits disappear from the stomach epithelum.
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  • 92
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    Cell & tissue research 198 (1979), S. 105-117 
    ISSN: 1432-0878
    Keywords: Swim bladder ; Physostome ; Cyprinid ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The swim bladder of the cyprinid Carassius auratus (goldfish) is a two-chambered organ connected to the esophagus by a pneumatic duct. The anterior chamber is lined by a single type of squamous epithelial cell. Two types of epithelial cells are present in the posterior chamber. Flattened cells with differences in the electron density of the cytoplasm line most of the chamber. Darker cells generally contain large amounts of glycogen. Cuboidal epithelial cells also occur in the posterior chamber. A glandular layer external to the muscularis in the posterior chamber is composed of large cells containing little glycogen, an extensive Golgi apparatus, and numerous mitochondria with single large granules. Capillaries and nerves are present in large numbers in this layer. Blood vessels form micro-retia mirabilia in the submuscular layer external to the glandular layer. Vessels are of two distinct types with wide lumina and flattened endothelium characterizing the venous vessels. Arterial vessels have smaller lumina, thick endothelial cells with prominent pinocytotic vesicles, and surrounding pericytes. Collagen is present in three forms in this swim bladder — large tactoids in the tunica externa of the anterior chamber, smaller tactoids in the lamina propria of the posterior chamber, and small fibrils in all other areas.
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  • 93
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    Cell & tissue research 199 (1979), S. 1-23 
    ISSN: 1432-0878
    Keywords: Neuro-intermediate lobe ; Hypophysis ; Disconnection ; Ultrastructure ; Colour change ; Control mechanisms ; Anolis carolinensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphological changes in the disconnected neuro-intermediate lobe were studied in the lizard, Anolis carolinensis from the 2nd to the 14th post-operative day using a threefold aldehyde fixative (Rodríguez, 1969). Two phases of colour change capacity were exhibited: Phase I started immediately after the transection, lasted for 6 days (mean) and was characterised by an excessive MSH release (brown skin). This phase proceeded gradually into Phase II, designated by an interruption of the MSH release (green skin). The degenerative processes and final elimination of neurons in the disconnected neural lobe propagate in a rostro-caudal direction from the transected area. The aminergic fibres (Type II) disappear within 2 days postoperatively, whereas the degeneration continues for more than 10 days in the peptidergic fibres (Type III, IV and V). The glia cells (ependyma and pituicytes) serve as very active macrophages, engulfing fragments of axons already affected by autolysis and transferring them into glial lysosomes. No apparent morphological changes occur in the shift from Phase I to II. The great majority of the secretory cells of the intermediate lobe are not affected by degenerative processes and appear to be markedly activated by the stalk transection. They exhibit numerous mitochondria, well-developed Golgi complexes forming numerous Golgi vesicles and extensive parallel cisternae of the rough endoplasmic reticulum, sometimes forming large intracisternal droplets (7 μm in diameter). Numerous pale vacuoles are seen, especially toward the intact capillaries, suggesting their coupling to the MSH release by extension of the active membrane area toward the perivascular septum. The number of these vacuoles is very markedly reduced in Phase II (no release), whereas the formation of new granules seems to proceed in early stages. The interruption of the MSH release implies a successive refilling of gradually growing secretory granules and a concomitant reduction in the development of the synthetic apparatus. Mechanisms probably involved in the control of the synthesis and release of MSH are discussed.
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  • 94
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    Cell & tissue research 201 (1979), S. 145-158 
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Secretory granules ; Endosalpinx ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of granules in the secretory cells of the endosalpinx of 20 Merino ewes was examined on days 1, 2, 3, and 4 post coitum. Based on the different frequency of granules of different size and structure on days one to four post coitum, one can assume that the ovoid, membrane bounded secretory granules mature in five successive stages. In stage I small, electron-lucent vesicles with a finely granulated and filamentous content become apparent, initially in the neighbourhood of the Golgi complex. In stage II the granules become larger and progressively more eletron-dense by an increase of the granulated material. In stage III, the primarily granulated content forms membranes, that lie in characteristic stacks at different angles to one another, separated by electron-dense areas. This structure fragments when the granule comes to lie beneath the surface of the cell (stage IV) and opens into the lumen of the oviduct, where its content is discharged in membrane fragments or vesicles (stage V). This discharge is mainly observed shortly before the egg is transported into the uterus.
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  • 95
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    Cell & tissue research 201 (1979), S. 305-314 
    ISSN: 1432-0878
    Keywords: Cockroach ; Muscle heterogeneity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have been performed upon the posterior coxal depressor muscle (136) and a coxal branch of the main depressor group (135d′) from the mesocoxa of the cockroach, Periplaneta americana. The quantitative stereometric analyses performed have shown the latter muscle to consist of a dorsal band of fibers having 25.5% mitochondria and 13.6% sarcoplasmic reticulum (SR) and T-tubules (TTS), and a ventral group of fibers with only 4.4% mitochondria and 26.6% SR/TTS. The volume fractions characteristic of the ventral fibers of muscle 135 d′ are also typical of muscle 136.
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  • 96
    ISSN: 1432-0878
    Keywords: HRP injection ; Lymnaea Stagnalis ; Neurohaemal areas ; Neurosecretory cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paired, electrotonically coupled neurosecretory Canopy Cells (CC) of the pond snail Lymnaea stagnalis were microiontophoretically injected with horseradish peroxidase (HRP). Whole mount preparations and ultrathin sections of injected CC were studied to describe in detail the morphology of the CC, their axon tracts and neurohaemal areas. The CC release their secretory product at three different sites, viz. from the soma and from axon terminals in the intercerebral commissure and in the median lip nerve. Neural control over the CC occurs by few synapses found exclusively on the CC axon, not on the cell body. One type of “en passant” synapse was identified. Two morphologically distinct types of synapselike structures (SLS) are numerous. The site of electrotonic coupling between the two CC is most probably located in the cerebral commissure. Serial sectioning showed that the axons contact each other over more than 130 μm. The contact is very intimate and the axon membranes interdigitate in a complex manner. Gap junctions, which are often described as the sites of electrotonic coupling, were not found.
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  • 97
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    Cell & tissue research 196 (1979), S. 39-57 
    ISSN: 1432-0878
    Keywords: Midgut (Collembola) ; Ultrastructure ; Cytochemistry ; Renewal ; Ageing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The midgut cells of Tomocerus minor (Insecta, Collembola) were examined with the electron microscope and cytochemically. The midgut epithelium consists of a series of cells characterised by numerous mineral concretions scattered throughout the cytoplasm. Mitochondria are abundant; microvilli are well developed at the apical surface of the cell. A zonula continua (continuous junction) characterises the apical contact region of these cells. Polysaccharides, glycoproteins and carbohydrate components have been demonstrated on the surface of microvilli. Peritrophic membranes surround the food bolus and preserve midgut cells from mechanical abrasion. Lysosomes are present during the alimentary period and show strong acid phosphatase activity. During an intermoulting cycle, two stages can be observed: (1) the postexuvial feeding period during which cytoplasmic extrusions appear at the apical part of the cell: lysosomes increase in number and autophagic vacuoles appear. (2) The preexuvial fasting period; a new epithelium grows beneath the old one and pushes it into the lumen. Degeneration processes can be observed in the old epithelium. This excretory reactivity of the midgut epithelium has been compared to the cycle of the cuticle.
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  • 98
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    Cell & tissue research 202 (1979), S. 133-143 
    ISSN: 1432-0878
    Keywords: Oogenesis ; Yolk formation ; Nurse cells ; Ultrastructure ; Diplura
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The egg chamber of Campodea consists of a group of nurse cells and an oocyte, and is surrounded by a simple, markedly flattened follicular epithelium. Three types of yolk occur in the oocytes: type I appears within elements of the rough endoplasmic reticulum; type II is produced by specific complexes of endoplasmic reticulum and dictyosomes; type III is incorporated by micropinocytosis. Histochemical tests show that mature yolk spheres contain proteins and polysaccharides. The main function of the nurse cells is to synthesize RNA, but they also produce small amounts of type I yolk. Phylogenetic conclusions are drawn from this and other studies of oogenesis in apterygote insects.
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  • 99
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    Cell & tissue research 202 (1979), S. 203-212 
    ISSN: 1432-0878
    Keywords: Mineralization processes ; Scales ; Teleost fish ; Matrix vesicles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In Teleost fish scales, growth and mineralization are continuous. Different mineralization processes can be distinguished. The external layer of the scale is the first to be mineralized and may be classified as the initial calcifying structure of the scale. The initial calcification loci are matrix vesicles of cellular origin always observed during the formation of this layer. This mineralization process takes place progressively, closely following the elaboration of the organic matrix in the scale periphery. The outer limiting and internal layers of the scale are developed after the external layer has been formed. A mineral substance is deposited without the mediation of matrix vesicles, but in contact with the previously mineralized external layer. This type of mineralization is called subsequential. However, the mineralization of the outer limiting layer closely follows the secretion of a collagen-free organic matrix and is thus different from the mineralization of the internal layer in which the calcification front remains remote from the collagen matrix surface and corresponds to a delayed mineralization process. The isolated calcifications (Mandl's corpuscles) which develop in the unmineralized laminae of the internal layer are mineralized in the absence of matrix vesicles and without making contact with a pre-existing calcified tissue, probably by a heterogeneous nucleation of the collagen fibrils.
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  • 100
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    Cell & tissue research 204 (1979), S. 95-109 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Gerbil ; Pinealocytes ; Morphometric analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By means of morphometric analytical procedures, a diurnal rhythm in the cellular volume of gerbil pinealocytes was determined. This rhythm has been attributed primarily to a change in the cytoplasmic volume of the pinealocytes which is low during the daylight hours and increases to reach a peak during the middle of the dark period. At the ultrastructural level, six cytoplasmic components of the pinealocytes were found to exhibit a rhythm: free cytoplasm, smooth endoplasmic reticulum (SER), rough endoplasmic reticulum (RER) and ribosomes, secretory vesicles, microtubules, and mitochondria. The presumptive secretory vesicles and the microtubules reached a peak in volume one hour before lights-off. It is suggested that lights-on and lights-off both signal a decrease in size and/or number of the secretory vesicles. The SER and RER/ribosomes reached their peak volume one hour after lights-off which is interpreted as indicating a peak in indoleamine synthesis and protein synthesis, respectively. The volume of free cytoplasm exhibits two peaks; one occurs one hour before lights-off while the second peak occurs in the middle of the dark phase. It is suggested that, although part of the secretory product of the pinealocyte may be present in dense-cored vesicles, other locations could include the free cytoplasm and clear secretory vesicles.
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