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  • 2000-2004
  • 1995-1999  (25)
  • 1990-1994
  • 1970-1974  (114)
  • 1999  (25)
  • 1974  (114)
  • Electron microscopy  (139)
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Years
  • 2000-2004
  • 1995-1999  (25)
  • 1990-1994
  • 1970-1974  (114)
Year
  • 1
    ISSN: 1432-1106
    Keywords: Key words Acetylcholine receptor ; Nicotinic ; Denervation supersensitivity ; Neuromuscular junction ; α-Bungarotoxin ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Through the use of biotinylated-bungarotoxin and monoclonal antibodies, the nicotinic acetylcholine receptor (nAChR) was localized in the subneural apparatus of mammalian motor end plates of the flexor digitorum brevis muscle of the adult rat at the light and electron microscopic levels. Under normal conditions, nAChR was located in the primary post-synaptic membrane of the neuromuscular junction, and the depths of the junctional folds constituting the secondary post-synaptic membrane did not contain any nAChR. Up to 75 days after repeated transection of the related motor nerve (sciatic), there was no major alteration in the light-microscopic localization of junctional nAChR in the subneural apparatus, except for a moderate shrinkage and increased immunocytochemical reactivity of the subneural apparatus. At the electron microscopic level, however, immunocytochemical reactivity gradually occupied the entire extent of the secondary post-synaptic membrane, including the depths of the junctional folds, which exhibited extensive branching. In non-innervated portions of the muscle fibers, nAChR receptor appeared in a linear localization on the surfaces of denervated muscle fibers. This linear reaction was not continuous with the nAChR reaction of the motor end plates. It is concluded that denervation supersensitivity might not be due to spreading of junctional nAChR from the end-plate area, but rather to expression of nAChR in non-innervated portions of the muscle fiber and to the infraterminal (subsynaptic) spreading of nAChR into the depths of junctional folds.
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  • 2
    ISSN: 1437-773X
    Keywords: Key words Gastrointestinal stromal tumor ; Gastrointestinal autonomic nerve tumor ; Electron microscopy ; Immunohistochemistry ; Gastrointestinal tract
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Sixteen gastrointestinal stromal tumors (GISTs) were studied by immunohistochemical analysis and an ultrastructural procedure. The tumor locations were as follows: esophagus (2), stomach (7), small intestine (3), and large intestine (4). Four of the lesions were classified as malignant, 2 as borderline, and 10 as benign. On the basis of the immunohistochemical analysis, the tumors were classified as follows: 1 as myogenic type, 2 as Schwann cell type, 8 as Cajal cell type (including 2 gastrointestinal autonomic nerve tumors, GANTs), and 5 as mixed-cell type. In each subtype the phenotype was compared to the ultrastructural findings. Myogenic and Schwann cell type revealed ultrastructurally smooth muscle differentiation and schwannian tumor. All 8 tumors of the Cajal cell type revealed interdigitating cytoplasmic processes with occasional clusters of filopodia. Two tumors were subdivided as GANT. Five tumors of mixed-cell type were composed of a mixture of cells with variable myogenic features or variable neural differentiation. We confirmed in this study that immunohistochemical analysis reflected electron microscopic findings.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Medical electron microscopy 32 (1999), S. 209-212 
    ISSN: 1437-773X
    Keywords: Key words Keratin ; Bile canaliculi ; Ecto-ATPase ; Transgenic mice ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Keratin 8 (K8) and keratin 18 are the intermediate filament proteins that are expressed in hepatocytes. A K8-deficient FVB/N mouse is a unique animal model for assessing the contribution of keratin intermediate filaments (IFs) to the structural and functional integrity of hepatocytes. Hepatocytes from homozygous (−/−) K8-deficient mice manifest a reduced bile acid secretion and an increased fragility to mechanical stress and hepatotoxic drugs. Hepatocytes from heterozygous (+/−) mice are more susceptible to drug-induced injury. Immunofluorescent microscopy revealed that hepatocytes from (+/−) mice maintained K8 IFs and F-actin that are similar to those in wild-type (+/+) mouse hepatocytes. In (−/−) mouse hepatocytes, K8 protein was negative and F-actin presented a coarse and irregular pattern. Ecto-ATPase, detected by enzyme histochemistry and observed by electron microscopy, was reduced in the bile canaliculi of both (+/−) and (−/−) mouse livers, in comparison with that of (+/+) mouse livers. These results reveal for the first time different microscopical findings regarding the livers of these three genotypes. They also suggest that the reduction of ecto-ATPase plays a role in the increased fragility of (+/−) and (−/−) mouse livers.
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  • 4
    ISSN: 1437-773X
    Keywords: Key words Small cell neuroendocrine carcinoma ; Parotid gland ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of small cell neuroendocrine carcinoma of the parotid gland is presented with immunohistochemical and electron microscopic studies. Small cell neuroendocrine carcinoma is extremely rare and is often difficult to distinguish from malignant lymphoma, adenoid cystic carcinoma, and undifferentiated carcinoma. Under light microscopy, the tumor cells consisted of solid sheets and nests of small tumor cells. Immunohistochemically, they were positive for KL-1 and EMA, and focally positive for NSE and synaptophysin. Observation using an electron microscope showed membrane-bound neuroendocrine granules in some tumor cells. Histological evaluation indicated that the present case was small cell carcinoma of the parotid gland, showing a neuroendocrine variety.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Medical electron microscopy 32 (1999), S. 167-174 
    ISSN: 1437-773X
    Keywords: Key words Apoptosis ; Docetaxel ; Human leukemia cell ; DNA fragmentation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We induced apoptosis in cells of the human leukemia cell line HL-60 using an antitumor agent, docetaxel (Taxotere), and investigated apoptosis in various aspects using in situ end-labeling (ISEL) of DNA, DNA fragmentation assay, flow cytometry, and electron microscopy. Because it inhibits depolymerization of tubulin, docetaxel is thought to arrest the cell cycle at the mitotic stage and to exert an antitumor effect. In this study, accumulation of docetaxel-treated cells at the G2/M phase was detected using flow cytometry. On ISEL of DNA, DNA fragmentation was observed at the mitotic stage. On electron microscopy, the nuclei of apoptotic cells lost their nuclear membranes, as do cells at mitosis, demonstrating that the cells were arrested mainly at the M phase in the cell cycle.
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  • 6
    ISSN: 1432-2307
    Keywords: Key words Melanin ; Oncocytic metaplasia ; Nasopharynx ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A 64-year-old man presented with a history of discomfort of the throat of a few weeks’ duration. Nasoscopic examination revealed multiple small, brown pigmentations at the left suprapharynx, the base of the left nasal cavity and the pharyngeal openings of the auditory tube on both sides. Microscopically, the lesion showed a glandular pattern of oncocytic epithelium with abundant pigmented granules and melanophages in the surrounding stroma. Immunohistochemically, the dendritic cells in the basal layer were positive for S-100 protein. Electron microscopic study revealed numerous fully melanized melanosomes and hypertrophied mitochondria in the oncocytic cells. Oncocytic cells do not produce melanin for themselves, melanin granules apparently being transferred from the adjacent dendritic cells to the oncocytic cells.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 200 (1999), S. 551-558 
    ISSN: 1432-0568
    Keywords: Key words Retina ; Development ; Retinal pigment epithelium ; Microglia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Blood-borne mononuclear cells invade the developing retina via the hyaloid vasculature at the optic nerve head. Following removal of apoptotic cell debris they give rise to the network of resident microglia. The population of cells recently described in the peripheral subretinal space of developing human eyes may represent a further population of macrophages destined to become microglia. The aim of the present study was to confirm the presence of subretinal macrophages in the developing eye in other mammalian species and perform preliminary immunophenotypic analysis in rat tissues. The range of species chosen included eutherian mammals (rat and rabbit) and marsupials (wallaby and opossum). Ocular tissues from a range of developmental stages were studied by scanning electron microscopy and transmission electron microscopy. Distinctive networks of dendriform and pleomorphic macrophages were observed by scanning electron microscopy in the peripheral subretinal space of D2 rabbits, newborn and D2 rats and D75 wallaby. Transmission electron microscopic studies of D2 rabbit, newborn and D2 rat and all ages of North American opossum revealed cells with the ultrastructural features of macrophages in the peripheral subretinal space, cilio-retinal junction and between ciliary epithelial cells. Preliminary immunoperoxidase studies using a panel of anti-leukocyte monoclonal antibodies on frozen sections of rat ocular tissues (newborn, D2 and D4) revealed ED1+ Ox42+ ED2+ but Ox6– cells in the peripheral subretinal space, peripheral retina and ciliary body epithelia. The data confirms that subretinal macrophages are a feature of the developing eye in a broad range of mammalian species and immunophenotypic evidence leads the author to postulate that these cells arise from the ciliary body vasculature and may migrate into peripheral neural retina and mature into resident microglia.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 98 (1999), S. 645-650 
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; Autopsy ; Electron microscopy ; Immunocytochemistry ; Motor ; neuron disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report two autopsy cases of motor neuron disease (MND) patients with an unusual type of muscular atrophy predominantly affecting the shoulder girdle and the upper extremities with proximal dominance. Both patients are considered to be clinically categorized into the El Escorial suspected form of amyotrophic lateral sclerosis (ALS). At autopsy, they showed marked loss of spinal anterior horn cells accompanied by astrogliosis positively immunostained with anti-glial fibrillary acidic protein antibody at the cervical level. At the lumbosacral level, anterior horn neurons were relatively well preserved and Bunina bodies, ubiquitin-positive skein-like inclusions and Lewy body-like inclusions were observed in the remaining neurons. In one patient, brain stem motor neurons (nerves V, VII, XII) and motor cortex, including Betz cells, were also affected and the corticospinal tracts were degenerated at the level of the thoracic and lumbar spinal cord. Pathological findings of this patient are consistent with those of ALS. In the other patient, the motor cortex, brain stem motor nuclei and the corticospinal tracts were well preserved, which is pathologically compatible with progressive spinal muscular atrophy. These patients with such a peculiar pattern of progressive muscular atrophy should be placed in a subgroup of ALS.
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  • 9
    ISSN: 1432-0568
    Keywords: Key words Vomeronasal organ ; Microvilli ; Monoclonal antibody ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The development of the rat vomeronasal organ was studied morphologically and immunocytochemically, using the monoclonal antibodies (MAbs) VOBM1, VOBM2 and VOM2 that react with the luminal surface of the vomeronasal sensory epithelium. Postnatal day (P) 7, 14, 21, 28, 35 and adult animals were examined. The vomeronasal organ and the blood vessel of the organ markedly increased in size and the vomeronasal glands increased in number between P7 and P14. At P35, the shape of the vomeronasal organ was similar to that of the adult but its size was slightly smaller. Electron microscopy showed that only a few scattered microvilli were present on supporting cells, and receptor cells were immature at P7. At P21, well-branched microvilli of the receptor cells and many microvilli of the supporting cells were observed on the luminal surface of the sensory epithelium. At P35, most apical endings of supporting cells and receptor cells were covered with numerous microvilli. Less developed areas were also present at the luminal surface of the epithelium at P35. At P7, immunoreactivities of the three antibodies were observed as discontinuous thin-layered bands only on the luminal surface of the sensory epithelium and no immunoreactivity was observed in other regions of the vomeronasal organ. Immunoreactivities of the VOBM1, VOBM2 and VOM2 increased with age and were observed as continuous thin-layered bands on the luminal surface of the epithelium by P35. These finding suggest that the development of the vomeronasal organ continues after birth and that the organ may reach maturity just before puberty (P42–49).
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  • 10
    ISSN: 1432-0533
    Keywords: Key words Unmyelinated fibers ; Peripheral nerve ; Electron microscopy ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Quantitation of unmyelinated fibers (UF) in peripheral nerves has classically relied upon ultrastructural morphometry. Because this method is time-consuming, it is not typically performed in routine analysis of nerve biopsies. We applied the Bodian-Luxol technique to detect unmyelinated axons by light microscopy on semithin sections from resin-embedded nerve tissue. Estimates were compared to ultrastructural counts. The staining appeared highly specific for axons. Excellent correlation was found between optic densities and the population of UF larger than 0.5 μm. The smallest profiles detected by light microscopy had a diameter close to 0.6 μm. This new technique is not a substitute for ultrastructural quantitative morphometry of UF, as very small unmyelinated axons, especially regenerating ones, can not be reliably visualized. However, it provides a valuable light microscopic method for evaluating axonal loss among UF.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 98 (1999), S. 330-336 
    ISSN: 1432-0533
    Keywords: Key words Micropolygyria ; Electron microscopy ; Frontal lobe ; Perivascular space ; Dot-like structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have reported breaches of glia limitans (GL)-basal lamina (BL) complex with protruding neuroglial tissue in Fukuyama-type congenital muscular dystrophy (FCMD) fetus brain and suggested that some basic deficits in the GL-BL complex may have a pivotal role in formation of micropolygyria in FCMD. We therefore investigated the cerebral GL-BL complex in seven FCMD cases (12–27 years of age), in three cases of Duchenne muscular dystrophy (17–25 years of age) and in two non-neurological controls (28 and 33 years of age). The frontal lobe cortex was examined immunocytochemically using antibodies against collagen type IV and laminin in each case, and ultrastructurally in an adult case of FCMD. In FCMD, the BL of the cortical surface was frequently breached with protruding neural tissue that ultrastructurally showed frequent synapses, neurites that had parallel arranged microtubules, and astrocytic processes. The outermost surface of this tissue was only partly lined by a BL. In the region of the gyral adhesion of micropolygyria, the perivascular space of the apparently entrapped meningeal blood vessels was occupied by neuroglial tissue, which is assumed to have invaded through the occasionally seen breaches of the perivascular GL-BL complex. Electron microscopy of the intruding tissue showed frequent synapses, microtubule-containing neurites and astrocytic processes. No breached GL-BL complex was found in any of the non-FCMD cases. These findings indicate that in FCMD, the cerebral GL-BL complex continues to have a crucial deficit with resulting breaches through which neuroglial tissue protrudes, promoting adhesion of the adjacent cerebral gyri during brain development before and after birth.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 199 (1999), S. 459-469 
    ISSN: 1432-0568
    Keywords: Key words Differentiation ; Electron microscopy ; Histochemistry ; Microtubules ; Neurofilaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The organization of the cytoskeleton has been studied during mouse differentiation in cells of the myenteric neuronal lineage. The entire gut was examined starting from day 12.5 of embryonic life (E12.5) until birth (P0). Immunocytochemistry was performed to evaluate the expression of five of the most represented neurofilaments proteins (the low, NF-L, medium, NF-M, and heavy, NF-H, molecular weight subunits, α-internexin and peripherin) and of two of the microtubule-associated proteins (MAP1 and MAP2a+2b). In parallel, the appearance in the differentiating myenteric neurons of filamentous and microtubular structures and their intracytoplasmatic distribution were observed under the electron microscope. A differential immunohistochemical expression of the structural proteins was found. Immature cells expressed α-internexin, peripherin, NF-M and MAP1 by day E12.5; α-internexin expression was strong in these cells, but gradually decreased with age and was practically absent in adulthood. Conversely, the expression of the other three proteins increased with cell differentiation and was still present in adulthood. NF-L and NF-H expression appeared later, by day E16.5, and was weak for the entire pre- and postnatal life. MAP2a+2b was never expressed. Under the electron microscope, at day E12.5 the cytoskeleton was already organized in filamentous and microtubular structures. At this age neurofilaments were few and mainly located in the cell processes, and microtubules were numerous and mainly assembled in the neuritic growth cones, together with synaptic vesicles. With ageing, neurofilaments and microtubules were ubiquitous in the neuron. Data obtained demonstrate that cytoskeletal proteins gradually accumulate in the cells of the neuronal lineage in parallel with the organization of the cytoskeletal structures, which in turn mediate important neural events by the earliest stages of murine embryonic life, including growth of nerve processes and initiation of axonal transport.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 125 (1999), S. 19-27 
    ISSN: 1432-1106
    Keywords: Key words Nerve injury ; Nerve repair ; Retrograde reaction ; Regeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Peripheral axotomy of adult cat spinal motoneurons induces a marked loss of synaptic boutons from the cell bodies and dendritic trees. The aim of the present study was to analyze the recovery of synaptic contacts in axotomized motoneurons following reinnervation into muscle. Adult cat spinal motoneurons were first deprived of their muscular contacts for 12 weeks and, then, allowed to reinnervate their target muscle. Two years later, regenerated motoneurons were labeled with horseradish peroxidase to allow quantitative ultrastructural analyses of the synaptic covering of the cell bodies and dendrites. Presynaptic boutons were classified according to their size and the shape of their synaptic vesicles. Results show that a recovery of synaptic covering occurs in the axotomized neurons after muscle reinnervation, but it affects various bouton types to different degrees. The number of S-type boutons synapsing with the soma was 70% higher after reinnervation than at 12 weeks after axotomy, while the number of F-type boutons had increased by only 13%. Compared with the normal situation, the number of S-type boutons synapsing with the proximal dendrites increased from 82% at 12 weeks after axotomy to 180% in the reinnervated state. In conclusion, in adult cat spinal motoneurons, the reestablishment of muscular contact is followed by a normalization of some of the synaptological changes induced by a prolonged state of axotomy. In certain respects restitution is incomplete, but in others it results in overcompensation.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 28 (1999), S. 263-267 
    ISSN: 1432-1017
    Keywords: Key words Human liver ; Human brain ; Ferritin ; Electron microscopy ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Human brain (globus pallidus) and liver tissues were investigated by means of electron microscopy (EM), Mössbauer spectroscopy (MS) and SQUID magnetometry techniques. Based on MS measurements, the iron present was identified to be in the ferritin-like form (61–88%) and in the form of a low-spin iron species (the balance). Its overall concentration was estimated as 1.5(3) mg in the brain and 2.4(5) mg in the liver, per gram of lyophilized tissue. The average core diameter was determined by EM measurements to be equal to 7.5(1.3) nm for the liver and 3.3(5) nm for the brain. Magnetization measurements carried out between 5 and 300 K yielded an estimation of an average blocking temperature, KT BL, as equal to 6.7 K and 8.5 K for the liver and the brain, respectively. From the dependence of KT BL on the external magnetic field it was concluded that the ferritin-like cores in the studied samples can be regarded as non-interacting particles. Finally, the uniaxial magnetic anisotropy constant was determined to be 6×103 J/m3 for the liver and 4×104 J/m3 for the brain.
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  • 15
    ISSN: 1432-1459
    Keywords: Key words CADASIL ; Cerebrovascular disease ; Skin biopsy ; Muscle biopsy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a microangiopathic syndrome. Although the defective gene has been identified, genetic analysis may be effort some due to its large size and various mutations. Providing a reliable diagnostic marker would therefore be helpful. Electron microscopy has revealed characteristic electron-dense granular deposits in the basal lamina of vessels of patients with CADASIL. We investigated the sensitivity of skin and muscle biopsies for diagnosing CADASIL. We examined 30 family members of three unrelated German families affected by CADASIL. In 14 of the 21 affected individuals we performed skin and muscle biopsies; two patients were clinically asymptomatic. Under electron microscopy all muscle and skin biopsy specimens showed patches of granular and electron-dense material in the basal layer of both arterioles and capillaries. These findings confirm that general microangiopathy is a typical feature of this syndrome and is present in the early phase of the disease with or without clinical manifestation. Thus, as electron microscopy of skin biopsy specimens can establish the diagnosis of CADASIL with high certainty, it may be considered the method of first choice.
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  • 16
    ISSN: 1432-2307
    Keywords: Key words Rhabdomyosarcoma ; Aorta ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report an intimal sarcoma presenting as an aortic aneurysm. A 68-year-old man suffered from chest pain and speech disturbance. Computed tomography showed a sacciform aneurysm of the aorta, which was resected, revealing a polypoid tumour measuring 1.5×2×2.5 cm projecting into the lumen. This proved to be a poorly differentiated high-grade sarcoma having morphological, immunophenotypic and ultrastructural features consistent with rhabdomyosarcomatous differentiation. Primary sarcomas of the aorta are extremely rare. Many cases have been diagnosed as ”intimal” on the basis of their site of origin, and they are not easy to classify from their histological pattern. Electron microscopy and the use of a more comprehensive panel of immunohistochemical markers should be applied in the histological classification of ”intimal” sarcoma.
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  • 17
    ISSN: 1432-0878
    Keywords: Key words Descending contralateral movement detector (DCMD) ; Identified neuron ; Vesicles ; Electron microscopy ; 3-D reconstruction ; Locust ; Schistocercagregaria (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The descending contralateral movement detector (DCMD), an identified descending interneuron in the brain of the locust Schistocerca gregaria has been investigated by using light and electron microscopy. We describe the fine structure, distribution and numbers of synapes that it receives from another identified brain neuron, the lobular giant movement detector (LGMD), and from unidentified neurons. The DCMD dendrites emerging from the integrative segment vary in form and number between individuals and sexes but always form a flattened dendritic domain. The arborizations and the integrative segment appear to be exclusively postsynaptic. Two types of synaptic contacts (Type 1 and 2) onto the DCMD can be discerned as having either round (Type 1) or pleiomorphic synaptic vesicles (Type 2) and by large (Type 1) or small (Type 2) subsynaptic appositions. Contact zones of Type 1 synapses are smaller than those of Type 2. LGMD-synapses are of Type 1 and occur intermingled with presynaptic sites of unidentified units. Some branches of the DCMD receiving input from unidentified units are devoid of contacting LGMD processes. Synapses of both types are randomly distributed over the DCMD integrative segment and at fibres with similar sizes.Type 1 synapses are much more frequent than Type 2 synapses and their number is negatively correlated with fibre diameter. For a whole DCMD dendritic arborization, a total of 8500 active zones of chemical synapses has been calculated, including a mininum of 2250 LGMD-synapses and about 1000 Type 2 synapses. The DCMD may thus receive a considerable amount of input from as yet unidentified neurons.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 296 (1999), S. 359-369 
    ISSN: 1432-0878
    Keywords: Key words Apoptosis ; Electron microscopy ; Meiosis ; Spermatocytes ; Spermatogenesis ; Testis ; TUNEL ; Mouse (10 strains)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Apoptosis of male germ cells is a widespread but little-understood phenomenon in many animal species. The elucidation of its mechanisms could be useful in the understanding of male infertility. We have examined the distribution of dying cells with the terminal transferase-mediated nick-end labeling (TUNEL) method and by an electron-microscopic procedure in the testes of 10 mouse strains, viz., C57BL/10 (B10), SL/NiA (SL), C57BL/6 (B6), C3H/He (C3H), BALB/c (BALB), DBA2 (DBA), CBA/J (CBA), MRL/MpJ-+/+ (M+), MRL/MpJ-lpr/lpr (lpr), and wild-type NJL mice (Mus musculus musculus). In the testes of the B10, NJL, SL, B6, C3H, BALB, DBA, and CBA mice, very few TUNEL-positive cells are distributed in the seminiferous tubules, whereas in the testes of the M+ and lpr mice, many TUNEL-positive cells, which are restricted to stage XII seminiferous tubules, have been identified. The most important finding is that many metaphases of meiotic spermatocytes show a marked TUNEL-positive reaction. Some metaphases show apoptotic morphology electron-microscopically. These results suggest that the testes of MRL strains will provide a useful model for the study of the mechanism of metaphase-specific apoptosis in meiotic spermatocytes.
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  • 19
    ISSN: 1432-0878
    Keywords: Key words Neuromelanin ; Neuron ; Peroxidase ; Oxygen metabolism ; High-definition light microscopy ; Electron microscopy ; Ultrastructure ; Cytochemistry ; Substantia nigra ; Lumbricusterrestris (Annelida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Histochemical examination of 1-μm tissue sections from the dorsal nerve plexus of the earthworm, Lumbricus terrestris, reveals multiple brown intraneuronal granules. These granules contain material morphologically and histochemically consistent with neuromelanin. When viewed with transmission electron microscopy, these were seen as single membrane-enclosed biphasic granules with diameters of 370–730 nm. Exposure of L. terrestris to high-level environmental oxygen resulted in an increase in the number of neuromelanin-like pigment granules within the neurons of the circular muscle layer. As measured by ortho-phenylenediamine hydrochloride, the endogenous peroxidase activity of extracts from worms incubated in high-level environmental oxygen was 51% more than controls. The endogenous peroxidase activity was localized in situ with 3,3-diaminobenzidine (DAB) and was found to increase in and around the neuromelanin-like pigment-containing neurons within the circular muscle layer. These studies suggest that the nerve net of L. terrestris may serve as a model to study the role of neuromelanin production in oxidative stress and its relationship to endogenous peroxidases.
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  • 20
    ISSN: 1432-0878
    Keywords: Key words Immunohistochemistry ; Electron microscopy ; Interstitial cells of Cajal ; F4/80 ; CSF-1 ; Kit-receptor ; Mouse (op/op)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The osteopetrotic (op/op) mutant mouse possesses an inactivating mutation in the colony-stimulating factor-1 (CSF-1) gene, which results in the absence of certain macrophages and in osteopetrosis, following a lack of osteoclasts. Studies of the op/op mouse indicate that CSF-1-dependent tissue macrophages may belong to a trophic and/or scavenger subpopulation, which through their effect on other cell types can significantly affect tissue functions, and that cells which are CSF-1 independent have antigen presentation and immunological functions.We have previously identified a cell system of regularly distributed macrophages in the muscularis externa of the small intestine and wanted to extend these studies to the op/op mouse.The present investigations with light- and electron-microscopic methods using fluorescent dextran, methylene blue and immunohistochemistry (F4/80, anti-kit receptor, anti-CD3, anti-CD45R/B220) show that macrophages are absent from the muscle layers, with only an occasional macrophage present in the subserosa. In the lamina propria and submucosa, macrophage numbers are reduced. In all other respects the muscularis externa appears normal, including normal organization and number of interstitial cells of Cajal. Control and op/op mice both lack cells expressing CD3 (T lymphocytes), CD45R/B220 (B lymphocytes) and mast cells in the muscularis externa. This leaves the muscularis externa macrophages as the most likely source of local cytokine production under such conditions as postoperative ileus and intussusception in infants, where the muscularis externa appears to be one target of cytokines. We conclude that the lack of macrophages, combined with the preservation of otherwise normal structure, will make the op/op mouse a valuable model by which to assess the functions and relative importance of the muscularis externa macrophages in relation to intestinal motility under normal and pathological conditions.
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  • 21
    ISSN: 1432-0878
    Keywords: Key words Caveolin ; Caveolae ; Lung ; Alveolar epithelial type I cell ; Immunocytochemistry ; Electron microscopy ; Confocal laser scanning microscopy ; Rat (CD)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Caveolae are flask-shaped invaginations of the plasmalemma which pinch off to form discrete vesicles within the cell cytoplasm. Biochemically, caveolae may be distinguished by the presence of a protein, caveolin, that is the principal component of filaments constituting their striated cytoplasmic coat. Squamous alveolar epithelial type I (ATI) cells, comprising approximately 95% of the surface area of lung alveolar epithelium, possess numerous plasmalemmal invaginations and cytoplasmic vesicles ultrastructurally indicative of caveolae. However, an ultrastructural appearance does not universally imply the biochemical presence of caveolin. This immunocytochemical study has utilised a novel application of confocal laser scanning and electron microscopy unequivocally to localise caveolin-1 to ATI cells. Further, cytoplasmic vesicles and flask-shaped membrane invaginations in the ATI cell were morphologically identified whose membranes were decorated with anti-caveolin-1 immunogold label. Coexistent with this, however, in both ATI and capillary endothelial cells could be seen membrane invaginations morphologically characteristic of caveolae, but which lacked associated caveolin immunogold label. This could reflect a true biochemical heterogeneity in populations of morphologically similar plasmalemmal invaginations or an antigen threshold requirement for labelling. The cuboidal alveolar epithelial type II cell (ATII) also displayed specific label for caveolin-1 but with no ultrastructural evidence for the formation of caveolae. The biochemical association of caveolin with ATI cell vesicles has broad implications for the assignment and further study of ATI cell function.
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  • 22
    ISSN: 1435-1536
    Keywords: Key words Double chain surfactants ; Aggregates ; Phase diagrams ; Lamellar phases ; Electron microscopy ; SANS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We present the phase diagrams and the properties of newly synthesised double-chain cationic N-alkyl-N-alkyl′-N,N-dimethylammonium bromide surfactants [C x C y DMABr (x = 12, 14 and 16; y = 10, 11, 12, 14 and 16)]. All the systems studied form liquid-crystalline lamellar phases but with different morphologies: unilamellar vesicles at low surfactant concentrations, multilamellar vesicles and tubular aggregates for surfactant concentrations between 2 and 10 wt% and at even higher concentrations planar bilayers of surfactant molecules in the classical Lα phase. The phase diagrams were determined with macroscopic and microscopic methods (polarisation microscopy, freeze-fracture transmission electron microscopy, scanning electron microscopy and differential interference contrast microscopy). The properties of the surfactant solutions were determined with differential scanning calorimetry measurements for Krafft point determination and small-angle neutron scattering measurements for interlamellar spacing and bilayer thickness. Finally, conductivity and viscosity measurements for phase characterisation were carried out.
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  • 23
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    European journal of epidemiology 15 (1999), S. 175-180 
    ISSN: 1573-7284
    Keywords: Electron microscopy ; Epidemiology ; Non-bacterial Gastroenteritis ; Oyster ; Small round structured viruses (SRSVs)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract From 1987 to 1992, 18 outbreaks of acute non-bacterial gastroenteritis occurred in Kyushu district. The most common symptoms were diarrhea, vomiting, nausea and abdominal cramp. Small round structured viruses (SRSVs) were detected in 52 (44.8%) of 116 stool samples from 17 outbreaks by the electron microscopy (EM) method, and a significant increase in the antibody level was noted in 42 (80.7%) of 52 paired serum samples from 12 outbreaks by the immune electron microscopy (IEM) method and in 18 (51.4%) of 35 samples from 8 outbreaks by the western blot (WB) method. However, according to the WB method, antigen-antibody reaction was not observed to reference antigen strips (SRSV-9/Tokyo 86-510, 63kDa) in three of the 8 outbreaks. The detected virus was regarded as an etiologic agent for these outbreaks. In four of 5 outbreaks which appeared associated with eating raw oysters, there was a close relation between SRSV infection and consumption of raw oysters.
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  • 24
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    Colloid & polymer science 277 (1999), S. 164-173 
    ISSN: 1435-1536
    Keywords: Keywords Nanostructures ; Thin films ; Vapor deposition ; Electron microscopy ; Optical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Colloidal dispersions of Yb, Er and Pr have been prepared by chemical liquid deposition. The metals were cocondensed at 77 K with 2-methoxyethanol and ethanol to produce solvated metal atoms. The particle size of the dispersions was determined by transmission electron microscopy to range from 52 to 1080 Å; the particles had spherical shapes. After solvent evaporation under vacuum, active solids and amorphous powder were deposited over Cu and Al metal. Dispersion stability, particle size, UV/Vis absorption and zeta potential were studied. The solids prepared by solvent evaporation were characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The films prepared on Al were studied by scanning electron microscopy. The most stable colloid was obtained using 2-methoxyethanol: several concentrations were stable for several months and the zeta potential indicated that this colloid stability is mainly due to solvation effects. FTIR spectroscopy of the solids indicated solvent incorporation in the film. This observation was corroborated by thermal analysis. Information on the thermal stability of the films was obtained by TGA. The UV/Vis absorption spectrum was measured at several concentrations under different conditions.
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  • 25
    ISSN: 1434-4726
    Keywords: Key words Laryngeal cancer ; p53 ; Oncoprotein ; Ki67 ; Proliferating cell nuclear antigen (PCNA) ; DNA ploidy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The difficult and complicated mechanism of cancer development with little knowledge about the biology of existing cancers can lead to a permanent search for new examination techniques to improve the precision of life expectancy in patients and the selection of the most efficient methods of treatment. The aim of this study was to analyze certain prognostic factors, i.e., p53, Ki67, proliferating cell nuclear antigen (PCNA), DNA ploidy and cell proliferating activity, as well as the degree of morphological differentiation and cell maturity evaluated on an ultrastructural level in patients with laryngeal cancers in connection with data obtained from follow-up examinations and the clinical course of the disease. Neoplastic tissue was taken from 120 patients with laryngeal cancers. All underwent surgical treatment, radiotherapy and combined treatment in the Department of Otolaryngology, Karol Marcinkowski University School of Medical Sciences, Poznań, Poland, and the Department of Otolaryngology – Head and Neck Surgery, Haukeland University, Bergen, Norway. Before beginning treatment all patients underwent histological verification of their neoplastic tissues. Histopathological examination proved that the majority of cases (95%) had a squamous cell carcinoma. The occurrence of changes within the lymph nodes of the neck (N) was significantly correlated with T, S, Ki67, metastases to lymph nodes, DNA ploidy, site and surgery performed. The degree of clinical progression (S) was intercorrelated with T, N, p53, Ki67, PCNA, DNA ploidy, site and laryngectomy. The occurrence of oncoprotein p53 in neoplastic cells was measured by the staining degree of their nuclei and was correlated with T, S, DNA ploidy, metastases to lymph nodes, PCNA and site. The degree of staining of neoplastic cells for the nuclear antigen Ki67 was correlated to T, N, G, S, DNA ploidy, metastases to lymph nodes and surgical treatment. The proliferative antigen PCNA in the examined population of patients was intercorrelated with T, p53, Ki67, metastases to lymph nodes and surgical treatment. The results obtained from DNA flow cytometry could be associated with N, G, p53, Ki67 and metastases to lymph nodes. On the basis of the results obtained, the techniques suggested for the morphological and biological evaluation of neoplastic cells in cancer of the larynx should include TNM classification + G + DNA + p53 + Ki67.
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  • 26
    ISSN: 1573-0832
    Keywords: Microsporon audouinii ; Pyrrolnitrin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Scanning and transmission electron microscopy showed that a ceiling quantity (1.56 mcg) of antifungal antibiotic Pyrrolnitrin caused heavy damage to dermathophyteMicrosporon audouinii Gruby CBS 313-54in vitro. Suitable preparation technique made it clear that the changes involved consisted of hyphal collapse on the edge of the culture, with loss of euplasmic organelles identity and cell autolysis. The cell wall, however, was apparently undamaged. These findings fit in with the suggestion that the mode of action of the antibiotic leads to generalised lipoproteic membranes damage. They must, however, be considered as representing the result of the terminal phase of cell distress.
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  • 27
    ISSN: 1432-0568
    Keywords: Calcitonin ; C-Cells of the thyroid and cells of the parathyroid glands ; Secondary hyperparathyroidism ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Im Verlauf ein- bis achtwöchiger Behandlung von Wistar-Ratten mit täglich 300 mMRC Einheiten Schweinecalcitonin kam es in den C-Zellen der Schilddrüse, verglichen mit denen der Kontrollserien (unbehandelte und mit Acetatpuffer allein behandelte Tiere), einerseits zu einer morphometrisch signifikanten Abahme der Zahl der Sekretgranula, während andererseits sämtliche Zellorganellen (Mitochondrie,, Golgi-Apparat und auch das granuläre endoplasmatische Reticulum) besser entwickelt waren. In den in gleichen Zeitabschnitten untersuchten Parathyroideazellen fanden wir bei mit Calcitonin behandelten Ratten Strukturveränderungen, die auf eine erhöhte Aktivität hinwiesen: Einfaltungen des Kerns, Erweiterung der Intercellularräume mit Vermehrung und Verlängerung der in diese hineinragenden Mikrovilli, bessere Ausbildung des Golgi-Apparates und des granulären endoplasmatischen Reticulums sowie eine größere Menge freier Ribosomen. Die Zahl der Sekretgranula war eindeutig höher als bei den Kontrolltieren. Der Ca ++- und Mg++-Blutspiegel zeigte während der ganzen Versuchsdauer bei allen Tieren keine statistisch faßbaren Änderungen. Die Autoren vertreten die Hypothese, daß die Aktivierung der C-Zellen durch das Auftreten eines durch die Calcitoninverabreichung hervorgerufenen sekundären Hyperparathyroidismus zustande kommt.
    Notes: Summary Male Wistar rats were injected for one to eight weeks with 300 mMRC units per day of porcine calcitonin. During this period C-cells (or “parafollicular” cells) of the thyroid gland and cells of the parathyroid glands were examined ultrastructurally. The C-cells were further studied morphometrically in animals treated with calcitonin dissolved in acetate buffer as well as in acetate buffer- and not-treated control animals. In the thyroid C cells the number of secretion granules significantly decreased following calcitonin administration, whereas the volume of all cell organelles (mitochondria, Golgi complex and granular endoplasmic reticulum) augmented. The cells of the parathyroid glands of the calcitonin-treated rats showed structural changes due to higher activity: invaginations of the nuclear envelope, enlargement of the intercellular spaces with increase in number and size of the microvilli, better development of the Golgi complex and the granular endoplasmic reticulum, larger population of free ribosomes and secretory granules. However, no significant differences in the blood calcium and magnesium levels were detected when a comparison was made of calcitonin-treated and control animals. All these observations support the hypothesis that the activation of the C-cells may result from a secondary hyperparathyroidism itself induced by the administration of moderate doses of calcitonin.
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  • 28
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    Anatomy and embryology 145 (1974), S. 187-196 
    ISSN: 1432-0568
    Keywords: Human skeletal muscle ; Sarcolemma ; Isolation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An isolation procedure for sarcolemma of human skeletal muscle is described. The method includes the possibility to prepare sarcoplasmic reticulum from the same muscle fibres. Electron microscopy reveals a homogeneous final fraction of 80–90% myofibre enveloping membranes contaminated by blood vessel membranes. The typical three-laminar composition of isolated sarcolemma is demonstrated. The mechanism of muscle fibre emptying is discussed.
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  • 29
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    Anatomy and embryology 144 (1974), S. 1-18 
    ISSN: 1432-0568
    Keywords: Mammals ; Mole ; Ovary ; Interstitial cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Ovar des Maulwurfs wurde licht- und elektronenmikroskopisch untersucht. Der Feinbau der verschiedenen Follikel und der Keimzellen entspricht dem anderer Species. Die Granulosa wird vermutlich erst mit der Ovulation luteinisiert. Sie enthält reichlich rauhes endoplasmatisches Reticulum und Sprossen von glattem endoplasmatischem Reticulum. Die Zellen der Theka interna leiten sich von Fibrocyten ab und enthalten neben reichlich glattem ER auch granuläres ER sowie Lipidtropfen und Mitochondrien mit Cristae und Tubuli. Diese Zellen ähneln in ihrer Feinstruktur stark den Zwischenzellen des ovarialen Marks. Dieses enthält in der Marksträngen Epithelien, die einer kräftigen Basalmembran aufsitzen. Sie werden teils als embryonal persistierende Vorstufen von Granulosa- oder Sertoli-Zellen, teils als Granulosasprossen aus der Rinde gedeutet. Für die Zwischenzellen des Marks erscheint eine Analogie mit den Hiluszellen des menschlichen Ovarialmarks bzw. eine Homologie mit den Leydig-Zellen des Hodens zweifelhaft. Als mögliche Quelle für diesen Zelltyp werden neben embryonal liegengebliebenen Anteilen auch Thekakeile und Epoophoronzellen sowie Fibroblasten diskutiert. Neben einer Steroid-synthese dürfte ihnen eine Reserve- und Speicherfunktion zukommen.
    Notes: Summary In order to make possible comparison between relatively primitive and relatively specialized gonads, the ovary of the mole was studied by light and electron microscopy. The ultrastructure of primary, secondary and tertiary follicles and of the germ cells is similar to that of other species. The granulosa cells of secondary and early tertiary follicles contain abundant rough endoplasmic reticulum and a small number profiles of smooth endoplasmic reticulum. The cells of the theca interna, which develop from simple fibrocytes are rich in smooth and rough endoplasmic reticulum and contain many lipid droplets and mitochondria, which possess both cristae and tubuli mitochondriales. At the time of ovulation, the granulosa cells are luteinized and their ultrastructure changes correspondingly. The medulla of the ovary is composed of the medullary cords and the interstitial cells. The medullary cords are solid epithelial cords, which are surrounded by a prominent basement membrane. They may be derived from embryonic precursors of granulosa—or Sertoli-cells or bud from the cortical zonae granulosae. There is a striking morphological similarity between the theca and interstitial cells. The interstitial cells of the ovarian medulla differ from the hilus cells of the human ovary and the Leydig-cells of the testis. They may develop either from embryonic rudiments of Leydig—or hilus-cell precursors, or bud from the theca or the epoophoron, or they may develop from fibrocytes. In addition to their suggested activity in steroid biosynthesis, the interstitial cells may have a trophic or storage function.
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  • 30
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    Anatomy and embryology 144 (1974), S. 75-83 
    ISSN: 1432-0568
    Keywords: Colonic mucosa ; Mouse ; Vacuolated cells ; Electron microscopy ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Swiss ICR adult male mice were used to analyse regional morphologic differences in the mucosa of the colon. The three cell types recently described in the descending colon of the mouse were also observed in the transverse and in the ascending colon. However the vacuolated cells of the crypts have presented different morphological characteristics depending on their localisation. In the ascending colon, they exhibited small supranuclear vesicles in contrast to the large vesicles observed in the descending colon. Several cell combining features of argentaffin-vacuolated, goblet-vacuolated and goblet-argentaffin cells have been observed. Furthermore a special type of granule referred to as a secondary lysosome was observed in the peripheral area of the typical goblet cells.
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  • 31
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    Anatomy and embryology 144 (1974), S. 85-100 
    ISSN: 1432-0568
    Keywords: X zone ; Electron microscopy ; Development ; Adrenal ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The postnatal development and involution of the X zone in the mouse adrenal cortex of both sexes were examined using the light and electron microscopes. At 0–5 days of age, no special cell group could be distinguished for the developing X zone in the inner cortex. The inner cortical cells contained spherical or ellipsoidal mitochondria with vesiculotubular cristae, vesiculotubular smooth endoplasmic reticulum (sER) and electron-lucent lipid droplets. The first sign of the developing X zone was the appearance of small groups of cells in juxtamedullary region differing from the cells in other part of inner cortex at 8 days. The electron microscopy showed that such cells contained nuclei of somewhat irregular outline and some parallel stacks of flattened sER. At 10–11 days, a thin layer of small eosinophilic cells were clearly identified as the developing X zone light microscopically in both sexes. Electron microscopically, the X zone cells showed a much dense cytoplas, which contained abundant sER, many mitochondria and numerous ribosomes. The typical X zone cells were characterized by the formation of peculiar mitochondrial complexes and whorled pattern of the sER. Mitoses were often found in the X zone, where mitotic cells even contained the whorled sER and bizarre mitochondria characteristic of the typical X zone cells. In the male the X zone rapidly involuted and might disappear by 30 days of age, whereas in the female X zone persisted as a thicker layer with the earlist sign of fatty degeneration. The origin of the X zone cell and the process of formation of its characteristic organelles are discussed.
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  • 32
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    Anatomy and embryology 147 (1974), S. 19-34 
    ISSN: 1432-0568
    Keywords: Gonads/embryology ; Swine/embryology ; Sex determination ; Electron microscopy ; Sex characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pig embryos aged 21–22 days (d) were obtained from artificially inseminated sows for an ultrastructural study of the development and sex differentiation of the gonadal ridge. The chromosomal sex of the embryos was identified by a chromosome analysis. At the age of 21 d the gonadal ridge consisted of three different tissue: the surface epithelium, the primitive cords, and the mesenchyme. The surface epithelial cells contained elongate mitochondria with lamellar cristae, granular endoplasmic reticulum (GER), the Golgi complex, free polysomes, coated vesicles and fine filaments. The epithelium was continuous with the primitive cords, which were composed of ultrastructurally similar cells. The epithelial basal lamina followed the cord surface, but covered it incompletely. Primordial germ cells (PGC) were located under the surface epithelium in the mesenchyme and in the cords. The nucleus with a prominent nucleolus, and the large mitochondria were round. The cytoplasm contained a pair of centrioles, the Golgi complex, solitary lamellae of the GER, free polysomes, lipid droplets and some coated vesicles. The PGC entered the gonadal cords before these were surrounded by the continuous basal lamina. A day later (22 d) the number and length of the cords were increased. The PGC were more frequent and seen also in deeper layers. All the structures studied at the age of 21–22 d showed that the gonadal ridge also at the ultrastructural level is at the sexually indifferent stage.
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  • 33
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    Anatomy and embryology 143 (1974), S. 215-222 
    ISSN: 1432-0568
    Keywords: Lung ; Stretch receptors ; Light microscopy ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Lappenbronchien (3./6.) (Durchmesser bei mittlerer Inspirationslage 500–700 μ) von männlichen und weiblichen Wistarratten wurden licht- und elektronenmikroskopisch untersucht. Diese Bronchien entsprechen im Wandbau den mittleren Bronchioli größerer Säugetiere. Freie, verzweigte lanzettförmige Terminalfasern werden im Bindegewebe der lamina propria beschrieben. Sie sind in das elastisch muskuläre System der Bronchuswand eingebaut. Die zugehörige markhaltige afferente Nervenfaser ist verzweigt und hat einen Durchmesser von 4–6 μ. Außerdem werden efferente motorische Endigungen an der glatten Bronchialmuskulatur beschrieben. Die freien lanzettförmigen und verzweigten Terminalfasern sind möglicherweise Dehnungsrezeptoren für den Hering Breuer Reflex.
    Notes: Summary In rats the 3rd to 6th bronchi, measuring 500–700 μ in diameter during inspiration, were investigated by light and electron microscopy. The histological appearance of these bronchi is comparable to that of medium sized bronchioles of larger animals. The branched and lanceolate terminals are associated with the connective tissue of the lamina propria and the smooth muscle cell layer. In this way the terminals are bound to the myoelastic system of the bronchial wall. The myelinated afferent fiber is branched and the diameter measures about 4–6 microns. Besides afferent nerve terminals these are numerous efferent endings on the smooth muscle basement laminae. It is supposed that the described receptor represents the pulmonary stretch receptor of the Hering Breuer reflex.
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  • 34
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    Anatomy and embryology 146 (1974), S. 95-111 
    ISSN: 1432-0568
    Keywords: Cerebellum ; Thalamus ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An experimental electron microscopical study has been made on the mode of termination of the cerebellothalamic projections in the cat. Supporting experimental light microscopical studies of silver impregnated sections following a large lesion of the cerebellar nuclei and light microscopical autoradiographic studies of the thalamus following injections of tritiated leucine in parts of the cerebellar nuclei, have been made as well. Following large lesions of the cerebellar nuclei, only the largest occuring type of bouton in the cat's VL and VA (type LR bouton) degenerates. Following such lesions, type LR boutons undergo a filamentous hypertrophy before becoming electrondense. One degenerating LR bouton establishes complex synapses with the dendrites of both thalamocortical relay cells and interneurons. Not all type LR boutons in VL and VA degenerate following lesions of the cerebellar nuclei. Light microscopical autoradiographic studies as well as experimental electron microscopical investigations indicate that cerebellothalamic fibers end in clusters within VL and VA, and that the areas of termination lie more rostrally within these thalamic nuclei than has been inferred from experimental studies of silver impregnated sections following lesions of the cerebellar nuclei. The findings are discussed with respect to relevant morphological and physiological data.
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  • 35
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    Calcified tissue international 16 (1974), S. 93-107 
    ISSN: 1432-0827
    Keywords: Dentinogenesis ; Globules ; Pyrophosphatase ; Calcification ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Three-day-old rats were fixed by perfusion with glutaraldehyde and thin slices were cut of the first molar germs. The slices were treated with EDTA and “activated” with buffered solutions containing Mg2+, Ca2+ or Zn2+. Incubation was carried out in buffered solutions (pH 8.5) containing inorganic pyrophosphate and Pb2+. In the Mg2+-activated specimens incubation products were localized to the plasma membranes in the stratum intermedium and the subodontoblastic area. Lead deposits were found on the periphery of the dentinal globules. Incubation products were more randomly distributed in Ca2+-activated specimens whereas those activated with Zn2+ displayed a deposition of lead precipitates mainly corresponding to that seen after activation with Mg2+. The findings are discussed in reference to the localization of alkaline phosphatase in the dentin-producing tissues and it is proposed that the results are indicative of the presence of an inorganic pyrophosphatase in these tissues.
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  • 36
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    Calcified tissue international 15 (1974), S. 213-220 
    ISSN: 1432-0827
    Keywords: Acid phosphatase ; Electron microscopy ; Shell Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Acid phosphatase activity was mainly localized in the lysosomes in all the regions of the outer epithelium. The transitional portion of the outer epithelium showed more intense activity than the other regions. During shell regeneration the activity of this portion decreased to a minimum level at 12 hours and was restored to normal at 72 hours. The other regions showed no change of activity during shell regeneration. It is postulated that the acid phosphatase in the transitional protion is responsible for conferring calcifiability to the organic matrix of the shell.
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  • 37
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    International archives of occupational and environmental health 32 (1974), S. 129-144 
    ISSN: 1432-1246
    Keywords: Lead intoxication ; Lead line ; Electron microscopy ; Stomato-Logy ; Bleiintoxikation ; Bleisaum ; Elektronenmikroskopie ; Stomatologie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die histologischen Befunde beim Bleisaum im Licht- und Dunkelfeld werden kurz besprochen. Die Beobachtungen stimmen mit den bekannten Angaben aus der Literatur überein. Elektronenmikroskopische Untersuchungen an Gingivabiopsien von 3 Patienten mit Bleivergiftung und deutlichem Bleisaum zeigten, daß die Ablagerungen sowohl extra- als auch intracellulär zu finden sind. Extracelluläres Blei war hauptsächlich zwischen kollagenen Pasern, um die Blutgefäße und in die Basallamina an der dermo-epidermalen Grenze eingelagert. Intracelluläres Blei war in einer Gruppe von Zellen in membranbegrenzten Phagosomen vorhanden, während es in anderen Zellen diffus im Cytoplasma verteilt war, wobei es zu einer Einlagerung in die verschiedenen cytoplasmatischen Membransysteme, besonders in die mitochondrialen Membranen, kam. Reste von lytischen Zellen mit diffus im Cytoplasma verteiltem Metall wurden von Makrophagen aufgenommen. Es wird vermutet, daß ein Cyclus abläuft, der mit der Phagocytose von Blei beginnt und über progrediente Zellschädigung zur Lyse führt. Die Ergebnisse werden mit Beobachtungen bei Argyrose verglichen. Das unterschiedliche Verteilungsmuster der Metalle bei diesen beiden Erkrankungen wird im Hinblick auf eine Hypothese über den Pathomechanismus von Schwermetallvergiftungen diskutiert.
    Notes: Summary The histology of the lead line is briefly reviewed on the basis of light- and dark-field microscope studies. The observations correspond with published data. Electron microscope studies on gingival biopsies obtained from 3 patients with lead intoxication and marked lead lines showed extra- and intracellular deposits of the metal. Extracellular lead was preferentially deposited between collagen fibers, around blood vessels and on the basal lamina of the dermal-epidermal junction. Intracellular lead was present within membrane-bound phagosomes of one group of cells, whereas it was diffusely distributed within the cytoplasm of another cell group. In the latter it was deposited on the different cytoplasmic membrane systems, particularly on the mitochondrial membranes. Residues of lytic cells, which contained diffusely distributed metal, were phagocytized by macrophages. It is assumed that a cycle starts with the phagocytosis of lead and ends with increasing cellular damage and cytolysis. The results are compared with the observations in argyria. The different distribution patterns of the metal in the two diseases are discussed in the light of a proposed hypothesis on the pathomechanisms of heavy-metal poisoning.
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  • 38
    ISSN: 1432-1459
    Keywords: Amaurotic Idiocy ; Late infantile Neuronal ceroid-lipofuscinosis ; Mental retardation ; Electron microscopy ; Inclusion bodies ; Membrane bound neuronal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es werden die lichtmikroskopischen, histochemischen und elektronenmikroskopischen Befunde in der Gehirnbiopsie eines Frühfalles von später infantiler Form der amaurotischen Idiotie (oder einer frühen Form der Batten-Spielmeyer-Vogt-Krankheit) beschrieben. An die Membranen gebundene cytoplasmatische Einschlußkörperchen sind in einigen wenigen Neuronen vorhanden. Die morphologischen Befunde werden mit Bezug auf die Ätiologie der Erkrankung diskutiert.
    Notes: Summary The light microscopic, histochemical and electron microscopic findings in a brain biopsy of an early case of Late Infantile Amaurotic Idioty (early form of Batten-Spielmeyer-Vogt disease) are reported. Membrane bound cytoplasmic inclusion bodies are present in a small number of neurons. The morphological findings are discussed in relation to the etiology of the disease.
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  • 39
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    Journal of neurology 208 (1974), S. 1-16 
    ISSN: 1432-1459
    Keywords: Neuroblastoma, central ; N-methyl-N-nitrosourea ; Transplacentar carcinogenesis ; Neuronal differentiation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die transplacentare Gabe von MNH an schwangere Ratten am 16. Tage der Gravidität, obwohl sie bei allen untersuchten Nachkommen zu Gehirnmißbildungen führte, erzeugte nur einen Tumor des Nervensystems. Dieser bösartige Tumor, bei dem am Lichtmikroskop die Diagnose Neuroblastoma gestellt wurde, wurde auch durch E.M. untersucht. Obwohl Strukturen stark andeutend auf unreife oder regressive synapsenartige Kontakte vorhanden waren, konnten gutentwickelte Synapsen jedoch nicht beobachtet werden. Bei den verschiedenen neuronalen Eigenschaften, die bei den Tumorzellen zum Vorschein kamen, besonders extensive Nissl-Schollen und zahlreiche „subsurface“ Zisternen, waren mehrere typisch für die embryonale Entwicklung der Nervenzellen: geästete Zellfortsätze mit Wachstumskonen und dense core, neurosekretorische Granula; diese Granula wurde als charakteristisch für neuerwachsende Nervenfasern angesehen. Die Anwesenheit dieser Entwicklungsmerkmale in einem Nervenzellenmalignom kann die vermutete embryonale Abstammung des Neuroblastomas als Abkömmling von unreifen Formen und nicht von entdifferenzierten Zellen bestätigen.
    Notes: Summary Transplacentar administration of MNU to pregnant Wistar-R rats at the 16th day of gestation, while inducing cerebral malformations in all the offspring examined, produced only one nervous system tumor. This malignant neoplasm, diagnosed optically as a neuroblastoma, was also examined at the EM level. Although structures strongly suggestive of incipient or abortive synaptic formations were present, well developed synapses were not observed. Among the various neuronal features displayed by the tumor cells, notably some extensive Nissl arrays and numerous subsurface cisternae, several were indicative of maturing nerve cells: branching tumoral processes provided with typical growth cones and dense cored “neurosecretory” vesicles. These vesicles are now considered to be one of the characteristics of newly developing nerve fibers. The presence of these developmental features in a nerve cell tumor helps to substantiate the embryonic origin of neuroblastomas postulated as arising from immature forms and not from dedifferentiated cells.
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  • 40
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    Cell & tissue research 147 (1974), S. 589-593 
    ISSN: 1432-0878
    Keywords: Ommatidium ; Apis mellifica ; Ninth retinula cell ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Das Rhabdom im Ommatidium der Arbeitsbiene wird von 9 Retinulazellen aufgebaut. Die exzentrische Zelle = Zelle Nr. 9 (ca. 50–75 μ lang) liegt im distalen Bereich des Ommatidiums, unterhalb der Zelle Nr. 4 (nach Varela und Porter, 1969), die ihrerseits den Rhabdomverband verläßt und als Axon zur Basalmembran zieht.
    Notes: Summary The rhabdom in the ommatidium of the worker honey bee is built up of 9 retinula cells. The eccentric cell = cell No. 9 (approx. 50–75 μ long) is situated in the distal region of the ommatidium beneath the fourth cell (numbered according to Varela and Porter, 1969), which in its turn leaves the rhabdom and runs as an axon towards the basement membrane.
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  • 41
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    Cell & tissue research 148 (1974), S. 397-406 
    ISSN: 1432-0878
    Keywords: Thymus ; “Nude” mouse ; Ciliogenesis ; Ciliary anomalies ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The thymus of the “nude” mouse is composed of ciliated cysts. In the adult mouse, different steps of ciliogenesis can be observed. The ciliated cells exhibit several anomalies in the centriole and in the cilium itself; the most important ones are the half-centriole and the compound cilia. An explanation for the occurrence of frequent anomalies in ciliated cells is suggested. Finally, some single cilia are described in fat cells.
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  • 42
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    Cell & tissue research 148 (1974), S. 499-504 
    ISSN: 1432-0878
    Keywords: Urethra (rat) ; Chromaffin cells ; Sensory neurons ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The urethra of the rat was examined by transmission and scanning electron microscopy. Under a transmission electron microscope flask-shaped chromaffin cells containing membrane-bound osmiophilic granules were seen to possess microvilli at their apical surfaces. The microvilli projected into large extracellular spaces which were apparently in continuity with the lumen of the urethra. Using scanning electron microscopy, a surface view of the lumen of the urethra was obtained. It showed a gently undulating surface with distinct intercellular boundaries. Scattered over the surface were numerous deep depressions between individual cells. These were thought to correspond with the large extracellular spaces into which microvilli had been seen to project. It is suggested that urethral chromaffin cells may “trigger” the afferent part of a reflex causing contraction of the urethral longitudinal muscle.
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  • 43
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    Cell & tissue research 148 (1974), S. 535-550 
    ISSN: 1432-0878
    Keywords: Synaptosomes ; Rat brain stem ; Synaptogenesis ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure and protein content of the five subfractions of the crude mitochondrial fraction from the brain stem of the 1-day old and adult rat was examined. The morphological composition of the subfractions after fixation in glutaraldehyde and osmiumtetroxide in the adult rat brain stem resembled that previously reported for the whole brain; synaptosomes sedimented in a sucrose gradient in subfractions C and D. In the 1-day old rat, mature synaptosomes were found in subfractions A, B, C and D; E contained mainly free mitochondria. 80–95% of the processes in the adult and 10–30% in the 1-day old rat contained synaptic vesicles which were of four types: (1) small agranular vesicles (2) large dense core vesicles (3) large agranular vesicles (4) coated vesicles. Pre- and postsynaptic membrane thickenings were demonstrated in many nerve-ending particles. In the subfractions of the 1-day old rat the protein content was one half and the distribution resembled that in the adult. Evidently nerve endings develop faster in the brain stem than in cortical areas; a serotoninor adrenergic origin of the early synaptosomes is suggested.
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  • 44
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    Cell & tissue research 148 (1974), S. 577-586 
    ISSN: 1432-0878
    Keywords: Node of Ranvier ; Axonal-glial junctions ; Cat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The paranodal zone of myelinated nerve fibers from the CNS of cats has been studied by means of the lanthanum technique and after freeze-etching. Special interest was given to the axonal-glial zones of contact in this region. Examination of the membranes of the paranodal pockets and the axolemma revealed that the membrane thickenings which occur between the adjacent membranes actually consist of bands. The bands show a specific pattern of diagonal running subunits 10 nm apart. These substructures of the axonal side of the membrane contacts protrude outwards, i.e. towards the glial membrane, where they fit into depressions on the glial membrane surface. This arrangement in form of a “zip-fastener” makes the whole structure very flexible. The subdivision of the bands was identified with both techniques. The different membrane aspects obtained by the freeze-etching technique are discussed in respect to the splitting theory, and a hypothetical model of this membrane specialization is presented.
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  • 45
    ISSN: 1432-0878
    Keywords: Structural water ; Fibrinogen-Fibrinmolecule ; Molecular morphology ; Electron microscopy ; Heat drying
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Standardgerinnsel aus Rinderfibrin wurden in der Kammer einer Versuchsanordnung einem mit Wasser nahezu gesättigten Luftstrom ausgesetzt. Die Gerinnsel kollabierten, und ihr Restwasser wurde in Zeitabständen durch Hitzetrocknung bei 105°C bestimmt. Es resultierte eine zeitabhängige Kurve, die aus 3 Phasen besteht. Elektronen-mikroskopische Aufnahmen zeigen, daß infolge eines Verlustes des freien Wassers während der ersten Phase das Pibringerüst des Gerinnsels kollabiert. Während der dritten Phase kollabiert das Proteingerüst der Fibrinmoleküle infolge des Verlustes von Strukturwasser. Während der zweiten Phase besteht das Gerinnsel aus raumfüllend gepackten Fibrinmolekülen. Das Strukturwasser beträgt dann etwa 5,25 g/g Trockengewicht; die Höhe ist etwa 180 μm und ergibt den wahrscheinlichsten Wert des Strukturwassers, 6,25 g/g Protein. Wenn dieser experimentelle Wert mit entsprechenden, theoretisch zu erwartenden Werten verglichen wird, die von elektronenmikroskopischen Molekularmodellen für Fibrin hergeleitet wurden, so ergibt das Gerinnsel, das aus raumfüllend gepackten Pentagondodekaeder-Modellen besteht, mit etwa 8 g Strukturwasser/g Fibrin die beste Näherung an den im Experiment erhaltenen Wert. Dieses Modell kann — im Gegensatz zu anderen Modellen — Massen-, Volumens- und Morphologieverhältnisse des Gerinnsels und des Moleküls erklären. Die verbleibende Differenz zwischen wahrscheinlichstem experimentellem und theoretischem Strukturwasser-Gehalt ist leicht durch experimentelle Ungenauigkeiten und Anwesenheit von Nicht-Fibrin im Molekularvolumen erklärbar. Mit an Sicherheit grenzender Wahrscheinlichkeit repräsentiert deshalb das Pentagondodekaeder-Modell die Allgemeinstruktur des Fibrin- und Fibrinogenmoleküls.
    Notes: Summary Standard clots of bovine fibrin collapsed in the highly humid air stream of a laboratory device. Their residual water, determined by heat drying at 105°C, resulted in a time dependent curve composed of 3 distinct phases. Electron micrographs show that during the first phase free water is released causing a collapse of the fibrous framework of the clot, during the third phase structural water is lost causing a breakdown of the molecular protein. The clot of the second phase consists of space fillingly packed fibrin molecules, whose directly determined structural water is approximately 5.25 g/g dry wt., but whose height (approximately 180 μm) results in the most probable value 6.25 g structural water/g protein. If this amount is compared with respective theoretical values of electron microscopic molecular models of fibrin, the clot consisting of space fillingly packed pentagon dodecahedron models yields approximately 8 g structural water/g fibrin, closely to the experimental value. In contrast to other models, this model explains simultaneously the shape of the curve, mass and volume relationships and morphology of clot and molecule. The remainding difference between the most probable experimental and this theoretical value can easily be attributed to experimental errors and impurities contained in the volume of the molecule. Consequently, the general structure of the fibrinogen and fibrin molecule is represented by the pentagon dodecahedron model.
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  • 46
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    Cell & tissue research 149 (1974), S. 481-495 
    ISSN: 1432-0878
    Keywords: Brain ; Monoamines ; Amphibia ; Fluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of monoamines in the brain of Bufo poweri was investigated with the Falck-Hillarp method. Green fluorescence was observed in neurons of the diencephalic preoptic recess organ (PRO) and its so-called additional cells, in the paraventricular organ (PVO) and its so-called accompanying cells, in the nucleus infundibularis dorsalis (NID) and in the mesencephalic nucleus reticularis mesencephali (NRM). Yellow fluorescence was found in some cells of the PVO and NID and in neurons of the caudal part of the NRM. Extensive tracts of aminergic fibres are described running caudo-rostrally and mainly terminating in the septa and striata of the telencephalon. It is suggested that the aminergic nuclei mentioned above partly contribute to the ascending tracts. Other fibres, originating in the PVO and NID are curving centro-caudally towards the median eminence. Although with the electron microscope some apparently aminergic nerve fibres were detected in the pars intermedia, such fibres have not been observed fluorescence microscopically. The ultrastructural study of the PRO has shown the presence of two types of aminergic liquor-contacting neurons. Among the distal cells of the PRO, aminergic and peptidergic neurons were distinguished. The presence of PRO additional cells, which are considered as a rostral extension of the PRO, is discussed with regard to the terrestrial habitat of the species.
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  • 47
    ISSN: 1432-0878
    Keywords: Sea anemone mesoglea ; Collagen synthesis ; Epitheliomuscular cells ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy and autoradiography (H3-proline) were used to determine the cell(s) responsible for collagen synthesis and lamination in the mesoglea of the sea anemone, Aiptasia diaphana. Mesogleal collagen is synthesized by the epidermal epitheliomuscular cells which contain much rough endoplasmic reticulum, and secretory vesicles attached to microtubules which cross the basal plasmalemma and anchor in the basement membrane; these cells incorporate large amounts of H3-proline. The mesogleal collagen fibers are non-striated, have clear centers, and a diameter of 200–260 Å; their walls are composed of 65 Å diameter subunit fibrils which appear to be helically oriented. Epitheliomuscular cells rest upon a subepidermal basement membrane which is composed of mesogleal collagen fibers, 65 Å subunit fibrils, and dense granules. This subepidermal basement membrane labels definitively with H3-proline, and is the region where soluble collagen precursors apparently form subunit fibrils which associate to yield mesogleal fibers. The columnar mesogleal collagen fibers are arranged to form layers: the fibers of each layer have the same longitudinal orientation, while those of adjacent layers display an approximate orthogonal arrangement. It is felt that the subepidermal basement membrane is responsible for this organization of mesogleal fibers. Mesogleal amoebocytes do not label with H3-proline and show no ultrastructural evidence of collagen secretion.
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  • 48
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    Cell & tissue research 150 (1974), S. 323-329 
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Mouse ; Multinucleate spermatids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscope studies of the testes of five inbred and three outbred mouse strains show that the usual frequency of multinucleate spermatids is between one and two percent. In C57 BL/6J and A/Gr however it is higher (4–5%). The frequency of the shared acrosome condition, which would lead to the formation of an abnormal sperm, is 1.3 per thousand.
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  • 49
    ISSN: 1432-0878
    Keywords: Lipofuscin ; Phagocytosis ; Vacuolization ; Capillary endothelium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dimethylaminoethyl p-chlorophenoxy acetate (80 mg/kg body weight) was administered (i. m.) to guinea pigs for 30 to 56 days. Electron microscopic examination of the hippocampus, mid-brain reticular formation and the area postrema revealed marked diminution in the electron density of the pigment granules and vacuolization. This type of lipofuscin was detected in some phagocytic cells and in the capillary endothelium. Conspicuous vacuolization of the capillary wall was discernible. These changes were not observed in the “control group” of animals.
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  • 50
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    Cell & tissue research 150 (1974), S. 425-442 
    ISSN: 1432-0878
    Keywords: Glandula submandibularis (Mouse) ; Acinar ultrastructure ; Cell types ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the submandibular gland of the mouse was studied by means of electron microscopy, from the 14th day of gestation up to birth. In the first two days the acini are solid and their cells contain polyribosomes and a few lamellae of endoplasmic reticulum. Beginning with the 16th day secretory granules appear and rapidly fill an increasing number of cells. The different electron density of the granules makes it possible to distinguish 1. two types of granules, dense and pale, and sometimes intermediate ones, 2. “polymorphic” granules. The latter consists of electron dense and electron pale parts combined in different configurations. The possible significance of the various types of granules is discussed.
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  • 51
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    Cell & tissue research 150 (1974), S. 409-423 
    ISSN: 1432-0878
    Keywords: Synaptic organization ; Trochlear nucleus ; Cat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two distinct types of neuron in the cat trochlear nucleus (one large, one small) are described, the α- and γ-motoneurons, respectively. Four types of terminals are observed which establish axo-dendritic synapses. Two of them (Types I and II) perform axo-somatic synapses as well. Terminals en passant (Types I and II) are predominant. The Type I terminal is long and slender with a characteristic distribution of the axoplasmic organelles and the unique feature of a relative narrowing of the synaptic cleft as compared to the width of the neighboring extracellular space. Its vesicle population is pleomorphic and a conspicuous glial barrier surrounds the synaptic zones. The Type II terminal differs slightly from Type I, revealing a wider synaptic cleft and lacking a characteristic distribution of the axoplasmic organelles. The type III terminal is rarely observed performing axo-somatic synapses, but is a common finding in the neuropil. Post-junctional dense bodies are often present in its axodendritic synapses. The Type IV nerve terminal performs axo-dendritic synapses and is characterized by a rich content of large granulated vesicles. Axo-axonal synapses are observed only very rarely. The synaptic organization of the feline trochlear nucleus is compared with the synaptic morphology of the oculomotor nuclei of inframammalian species (Waxman and Pappas, 1971). In addition to certain similarities (e.g., richness of synapses en passant), significant differences are encountered: the present study provides no morphological evidence for electrotonic transmission in the trochlear nucleus of cat.
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  • 52
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    Cell & tissue research 150 (1974), S. 521-527 
    ISSN: 1432-0878
    Keywords: Muscle spindle ; Intrafusal fibres ; Myofilaments ; Electron microscopy ; Quantitative stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Muscle spindles contain two types of intrafusal muscle fibre, nuclear bag fibres and nuclear chain fibres. The intrafusal fibres of rabbit and guinea pig spindles have been studied using quantitative stereological techniques at the ultrastructural level. The crosssectional areas occupied by myofilaments have been measured in the polar and equatorial regions of both types of intrafusal fibre. There are considerably fewer myofilaments in the equatorial regions of both types of fibre compared with their polar regions.
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  • 53
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    Cell & tissue research 151 (1974), S. 281-292 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mitochondria ; ACTH ; DNA-synthesis ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a chronic ACTH administration (up to 12 consecutive days) on the 3H-thymidine uptake by the mitochondrial compartment of rat adrenal zona fasciculata were investigated by high resolution autoradiography, and compared with the changes in volume and number per cell of these organelles induced by the hormonal treatment. Up to the 9th day of treatment there is a significant increase in the tracer incorporation into adrenocortical mitochondria which is coupled with a significant increase in the volume of the organelles. After 12 days of hormone administration a significant decrease in the 3H-thymidine mitochondrial uptake is found, which is associated with a conspicuous increase in the number of mitochondria per cell and a net decrease in their average volume. The data are discussed in the light of evidence indicating that mitochondria possess a genetic apparatus largely independent of nuclear control. It is hypothesized that ACTH controls the growth and proliferation of adrenocortical mitochondria and that the mechanism of this action of ACTH involves stimulation of the mitochondrial DNA synthesis.
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  • 54
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    Cell & tissue research 151 (1974), S. 269-280 
    ISSN: 1432-0878
    Keywords: Trichomonas vaginalis ; Adenosine triphosphatase ; Acid phosphatase ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two intracellular phospho-hydrolases are revealed in cells of Trichomonas vaginalis. One of the enzymes is an acid phosphatase and the other a nucleoside triphosphatase (ATP-ase). Both enzymes are found to be present in the Golgi saceuli and vesicles of the cells. The ATP-ase activity has prevalence to the more superficially positioned saceuli of the Golgi region and the acid phosphatase to the more deeply positioned saceuli. Both enzymes are also found in the phagolysosomes but only acid phosphatase could be demonstrated in the small primary lysosomal structures of the cell cytoplasm. The findings indicate that both enzymes are active in the hydrolytic processes associated with endocytosis of foreign matter.
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  • 55
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    Cell & tissue research 151 (1974), S. 385-394 
    ISSN: 1432-0878
    Keywords: Membrane particles ; Cockroach hemocytes ; Freeze-fracture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Freeze-fracture studies were conducted on the membranes of normal cockroach hemocytes. The plasmalemma is asymmetric with the A fracture face containing 80–100 Å membrane intercalated particles at a concentration of ∼2500/μ2. The B fracture face contains 120–150 Å particles with a relatively low density (∼800/μ2). The nuclear envelope displays an asymmetry with the A fracture face containing ∼1500 particles/μ2 and the B face containing ∼300/μ 2. No significant particle size differences were observed in nuclear envelope fracture faces. Two types of symmetric membranes were also found in these cells. Both A and B fracture faces of the membrane surrounding the numerous cytoplasmic inclusion bodies contain particle sizes and concentrations similar to the B face of the plasmalemma. A second type of symmetry was observed in cells apparently engaged in “exocytosis”. Vesicles (∼0.1 μD) from this process were completely particle free on both fracture faces. Such particle free vesicles could be found in the cytoplasm, attached to the plasmalemma, or completely separated from the cell.
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  • 56
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    Cell & tissue research 151 (1974), S. 457-469 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Rat ; Adrenalectomy ; Renin and secretory granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Reaktion des juxtaglomerulären Apparates auf Adrenalektomie wurde untersucht. Im Stadium der Nebenniereninsuffizienz, sechs Tage nach der Operation, wurde quantitativ morphometrisch eine Abnahme der Volumendichte der Sekretgranula (von 32% auf 16%) festgestellt. Golgi-Apparat und Ergastoplasma proliferieren stark, wobei insbesondere die erweiterten Cisternen des Ergastoplasmas auffallen.
    Notes: Summary The response of the Juxtaglomerular apparatus to bilateral adrenalectomy was studied in rats. After the sixth postoperative day, symptoms of severe adrenal insufficiency had developed. In the Juxtaglomerular cells, the volume density of the secretory granules decreased from 32% to 16%. The Golgi apparatus and rough endoplasmic reticulum underwent considerable proliferation, the latter showing strikingly enlarged cisternae.
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    Cell & tissue research 151 (1974), S. 433-456 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus (Rat) ; Development ; Renin ; Pools ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die perinatale Entwicklung des juxtaglomerulären Apparates, insbesondere das Verhalten der epitheloiden Zellen wurde an 18 trächtigen Ratten and 65 Embryonen bzw. Jungtieren elektronenmikroskopisch untersucht. Parallel dazu wurde die Reninkonzentration bzw. der Reningehalt bestimmt. Spezifische Sekretgranula finden sich erstmals am 18. Tag der Fetalzeit, und zwar in den epitheloiden Zellen des juxtaglomerulären Apparates juxtamedullärer Nephrone. Die Granula machen einen Struktur- und wahrscheinlich auch Funktionswandel durch, der eine Einteilung in drei verschiedene Granulatypen nahelegt. Diesen drei Typen spezifischer (reninhaltiger) Sekretgranula werden die Lysosomen als unspezifische Einschlüsse der epitheloiden Zellen gegenübergestellt. Im einzelnen kommt es während der perinatalen Phase in den fetalen Epitheloidzellen zuerst, d.h. pränatal, zu einer Hypertrophie des rauhwandigen endoplasmatischen Retikulums und des Golgi-Apparates. Hierin sehen die Autoren einen Hinweis auf eine erhöhte Proteinsynthese mit entsprechender Zunahme der Transport- und Konzentrationsvorgänge. Nach der Geburt findet sich dann auch eine deutliche Zunahme der Sekretgranula vom Typ III, die als reife Reningranula (mature granules) angesehen werden. Die bisher noch nicht beschriebenen kleinen Sekretgranula vom Typ I dagegen kommen in weniger entwickelten Epitheloidzellen häufiger vor. Bestimmungen der Reninverteilung zwischen Zytoplasma und den durch Differential-zentrifugation gewonnenen Granula-Fraktionen ergeben auffallende Parallelen zu den morphologischen Befunden. Diese sprechen im allgemeinen dafür, daß “freies Renin” im Ergasto-plasma und “gebundenes Renin” in den Sekretgranula vorliegt. Mit zunehmendem Alter scheint es außerdem — parallel zur relativen Abnahme des Ergastoplasmas und Zunahme der reifen Reningranula — zu einer Verminderung des extragranulären zugunsten des granulär gebundenen Renins zu kommen.
    Notes: Summary The perinatal development of the Juxtaglomerular apparatus (JGA), with particular reference to the epithelioid cells, was studied. Electron microscopic studies were carried out on 18 gravid rats and 65 embryos with corresponding determinations of renin concentration and the renin contents by bio-assay. Specific secretory granules of the epithelioid cells of the JGA of juxtamedullary nephrons are first observed on the 18th day of gestation. The classification into three types of secretory granules suggests that they undergo a structural and probably also a functional transformation. All three types of secretory granule may be regarded as specific, renin-containing, cytoplasmic organelles. During the last days of gestation, the rough-surfaced endoplasmic reticulum and the Golgi apparatus become hypertrophied in epithelioid cells, indicating an increased protein synthesis as well as transport and concentration processes. After birth, there is a definite increase in the number of Type III secretory granules-which may be regarded as mature granules. The small Type I secretory granulesnot previously described-are found more frequently in the immature epithelioid cells. Determinations of the renin distribution in the plasma and in fractions of cytoplasmic constituents (total homogenate, secretory granules) prepared by differential centrifugation showed striking congruence with the morphological findings. It is generally assumed that “soluble renin” occurs in the endoplasmic reticulum and “bound renin” in secretory granules. A shift from extragranular to granular (bound) renin, occurs with increasing age, having its morphological equivalent in the relative decrease of the endoplasmic reticulum and increase in mature secretory granules.
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    Cell & tissue research 152 (1974), S. 69-92 
    ISSN: 1432-0878
    Keywords: Pituitary ; Freshwater stickleback ; Morphometry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new approach to the ultrastructure of fish pituitary glands is presented. A morphometric analysis of the cell types in the pituitary gland of the adult, winter, fresh-water stickleback, Gasterosteus aculeatus form leiurus, reveals differences between both the relative and absolute volumes of the various organelles in different cell types. The morphometric data on the relative volumes of the organelles, together with section profile diameters of the secretory granules and information on the surface area: volume ratio of the nuclei are then used to build “reconstruction drawings” of “average” cells. A distinction is made between the ultrastructural description and identification of cell types.
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  • 59
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    Cell & tissue research 152 (1974), S. 283-292 
    ISSN: 1432-0878
    Keywords: Sense organ ; Lateral line ; Synapses ; Ambystoma mexicanum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lateral line organs in young salamanders of the species Ambystoma mexicanum were investigated with scanning and transmission electron microscopy. They were found to differ from the lateral line organs in adult animals (1) by being lower, having short hair cells and supporting cells, (2) by the hair cells having areas of lateral contact, (3) by the occasional presence, at the edge of the organ, of hair cells at an early developmental stage. Two types of nerve endings are seen: (1) afferent, and (2) less commonly, efferent vesiculated ones. Synaptic bodies have been seen in the cytoplasm without association to afferent synapses.
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  • 60
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    Cell & tissue research 152 (1974), S. 513-523 
    ISSN: 1432-0878
    Keywords: Ovary ; Corpus luteum ; Innervation ; Fluorescence histochemistry ; Electron microscopy ; Quantitative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Qualitative and quantitative studies were made to determine the amount of nerve fiber supplying corpora lutea (CL) of rats during the oestrous cycle and pregnancy and sow CL during days 4–6 after ovulation. Fluorescence microscopy of freeze-dried, paraformaldehyde treated (Falck-Hillarp method) rat ovaries reveals adrenergic nerve fibers which run along with vessels and form a network among interstitial gland cells. Nerve fibers do not enter the granulosa cell layer in follicles or CL. In the CL circumference both vascular and non-vascular nerves occur the latter being related to the fibromuscular layer and probably innervating smooth muscle cells. No striking differences exist between the innervation of the ovary in non-pregnant and pregnant rats. Bodian and methylene blue staining did not contribute to a more detailed knowledge of rat ovary nerve supply. Electron microscopic quantitative analysis of rat and pig CL (rat: day 18 of pregnancy; pig: day 4–6 after ovulation) revealed no axon profiles in 2.000 grid squares (one square measuring 2.25×10-2 mm2) of randomly taken CL sections. Thus it was possible to calculate an upper limit of 133 μm of nerve fibers per 1 mm3 CL tissue, in case there were any at all.
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  • 61
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    Cell & tissue research 152 (1974), S. 525-542 
    ISSN: 1432-0878
    Keywords: Nidation ; Mice ; Cell interaction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The interaction between the trophoblast and the maternal epithelium at early implantation was studied by means of light and electron microscopy. The uterine horns were fixed in situ and a double-embedding method was used to locate implantation sites. Observations were made on mice killed at 2 hour intervals 90–116 h. post coitum which covered the following stages: pre-attachment (i) with zona pellucida intact (ii) with zona pellucida in dissolution (iii) after loss of the zona; attachment; adherence; and invasion. The intact zona pellucida was electron opaque and of uniform density. In the stage of apparent dissolution it became electron dense and was trapped between trophoblast and epithelium. At preattachment the trophoblast cells were round. Subsequently they became long and attenuated, often with lysosomes in the cytoplasm proximal to the epithelial layer. Epithelial cells, which could be seen in various stages of degeneration were apparently phagocytosed by the trophoblast. Occasional pyknotic epithelial cells were seen, as well as some apparently normal ones which contained cytosegresomes. The possible reasons for their presence are discussed. The microvilli of the epithelial cells changed from regular and pointed at preattachment to short and irregular at adherence and invasion.
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  • 62
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    Cell & tissue research 153 (1974), S. 15-30 
    ISSN: 1432-0878
    Keywords: Graafian follicle (Rabbit) ; Ovulation ; Connective tissue ; Muscle, smooth ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tunica albuginea in ovaries of sexually mature rabbits is only a few cell layers thick but is much more densely packed with collagen bundles than the broad theca externa of the Graafian follicles. Smooth muscle cells were demonstrated in theca externa around the whole follicle; ultrastructural evidence of smooth muscles in the apical region of theca externa in rabbit follicles has not been presented previously. At 8 hrs after injection of an ovulatory dose of HCG oedema was observed below the germinal epithelium covering preovulatory follicles. In the oedematous area, dead or degenerating cells could be found, and the underlying tunica albuginea contained degenerated fibroblasts and showed dissociation and fragmentation of the collagen. The alterations gradually proceeded inwards, and, at 9.5 hrs and later, marked changes were obvious even in the innermost portion of theca externa. The observation that the changes started, and were most pronounced, in the collagen-rich tunica albuginea and gradually proceeded inwards, supports the hypothesis that lytic substances emanating from the surface epithelium covering preovulatory follicles play a central role in effecting follicle rupture.
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  • 63
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    Cell & tissue research 153 (1974), S. 89-99 
    ISSN: 1432-0878
    Keywords: Retinohypothalamic projection ; Passer domesticus ; Suprachiasmatic nucleus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The possibility of a direct retinohypothalamic projection was reinvestigated in Passer domesticus by electron microscopy following left unilateral retinectomy. To avoid misinterpretation of non-specific degeneration, the course of degenerative changes was observed at intervals of 6, 12, 24, 48 and 96 hours after operation. Of the hypothalamic areas examined in only one, the contralateral suprachiasmatic nucleus, was it possible to identify reliable indications of secondary anterograde degeneration comparable to those observed in the contralateral optic tectum. Single dark profiles within the supraoptic nucleus and the basal infundibular (tuberal) nucleus showed neither internal changes in structure nor an increase in number per unit area in retinectomized birds. Since photoperiodically induced gonadal growth occurs in totally blinded birds the functional significance of the retinohypothalamic projection to the suprachiasmatic nucleus is open to discussion.
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  • 64
    ISSN: 1432-0878
    Keywords: Branchiostoma ; Kölliker's pit ; Hatschek's pit ; Wheel organ ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Kölliker's and Hatschek's pit and the wheel organ in the head region of Amphioxus have been studied with the electron microscope. Kölliker's pit is lined by ciliated cells lacking specific ultrastructural characteristics which might suggest an olfactory function. No nerve terminals have been found near this structure. The wheel-organ consists of tall ciliated cells, which occasionally have been found to be innervated and which are clearly marked off the rest of the epithelial lining of the oral cavity. The epithelium of Hatschek's pit again is ciliated and possesses markedly euchromatin rich nuclei. In the area of Hatschek's pit numerous epithelial cells have been observed which possess accumulations of small granules and vesicles in their basal cytoplasm. Such basally granulated cells occur in the immediate neighbourhood of blood spaces of the glomus and other vessels; the connective tissue between blood and epithelium is loosened up or has completely disappeared. The question of homology of the structures investigated with the olfactory groove and hypophysis of vertebrates is briefly discussed.
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  • 65
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    Cell & tissue research 153 (1974), S. 245-251 
    ISSN: 1432-0878
    Keywords: Elastic fibres ; Notochord Rana rugosa ; Elastogenesis, Elastica interna ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The elastica interna was studied in the notochord sheath of the caudal one third of the tail of Rana rugosa tadpoles. Dense amorphous bodies are present in depressions at the surface of superficial notochord cells. These bodies are intimately associated with microfibrils. The notochord basement membrane tends to cover the surface of the dense amorphous bodies but often appears to fuse with them and disappear. There is a striking close resemblance between the amorphous dense bodies and the elastica interna. These observations, together with the observation of dilated cisterns of granular endoplasmic reticulum with dense contents in the cytoplasm of superficial notochord cells, suggest that the amorphous dense bodies and the elastica interna are produced by superficial notochord cells.
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  • 66
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    Cell & tissue research 153 (1974), S. 449-464 
    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Bufo bufo ; Macula densa ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the juxtaglomerular apparatus in the toad, Bufo bufo was investigated.—It is suggested that the granules in the media cells of the afferent arteriole are formed from the Golgi apparatus. Many granules have a content of lamellar material. The media cells do not show the ultrastructural features of active secretory cells. In the media cells, the myofilaments are situated near the vascular lumen. The other cell organelles, including the granules, are preferentially located at the opposite pole of the cell in the neighbourhood of the macula densa cells and the adventitial nerve fibres. In these regions the media cells show many pinocytotic vesicles. The nerve fibres innervating the juxtaglomerular cells are non-myelinated and their varicosities contain dense core vesicles. The basement membranes of media cells and adjacent macula densa cells occasionally fuse, which may indicate a functional relationship between these cells.
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  • 67
    ISSN: 1432-0878
    Keywords: Spleen (human) ; T and B cell regions ; Localization ; Enzyme cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The capacity of certain B-lymphocytes to bind complement (demonstrated by erythrocyte-antibody-complement complexes, EAC) was used as a marker of the B-lymphocyte regions of the human white splenic pulp. This was carried out on cryostat sections in order to correlate enzyme histochemical findings (5-nucleotidase, ATPase, acid phosphatase, nonspecific esterase, alkaline phosphatase) to immunological functions. EAC were typically found in the follicle centers and marginal zone, whereas periarteriolar lymphocyte sheaths remained negative. The enzyme histochemical patterns of lymphocytes and reticulum cells allowed a clear distinction between areas with and those without EAC-binding. This was shown most clearly when the following enzymes were demonstrated in combination: 5-nucleotidase (5-Nase) + alkaline phosphatase, ATPase + acid phosphatase, and nonspecific esterase + acid phosphatase. 5-Nase correlated best to EAC-positive areas with a positive reaction in follicle wall lymphocytes and dendritic reticulum cells, whereas periarteriolar sheaths contained no 5-Nase-positive structures. Reticulum cells around periarteriolar lymphocyte sheaths at the margin of the red splenic pulp showed a particularly strong alkaline phosphatase reaction. The reticulum cells of the areas containing B-lymphocytes and those of the EAC-negative periarteriolar regions, which probably contain T-lymphocytes, were specifically labeled for different sets of enzymes. These findings suggest that specialized, morphologically different reticulum cells may be the “guide rails” for the different freely circulating lymphocyte populations.
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  • 68
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    Cell & tissue research 155 (1974), S. 367-381 
    ISSN: 1432-0878
    Keywords: Rodlet cell ; Pear-shaped cell ; Rhabdospora thelohani ; fishes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rodlet cells from many species of fresh water fish were examined with the electron microscope. Observations of these cells in the epithelia of intestine, gill, and other organs favor the interpretation that rodlet cells are secretory cells rather than protozoan parasites (Rhabdospora thelohani). Evidence is presented that rodlet cells develop from undifferentiated cells near the epithelial basement membranes and migrate“upward” to secrete their contents in a holocrine manner at the epithelial surface. The major secretory product is packaged in unique club-shaped sacs which contain a central core of highly electron dense material with less dense material surrounding it. Secretion often appears to be accomplished by active contraction of a 0.5 μm fibrillar border resembling smooth muscle which lies just inside of the plasma membrane. Some rodlet cells, however, merely break apart and release their contents.
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  • 69
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    Cell & tissue research 155 (1974), S. 437-447 
    ISSN: 1432-0878
    Keywords: Lung ; Fishes ; Polypterus ; Cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytochemical similarities between the polypterine and mammalian lung are presented. The ultrastructural localization of reaction products from ruthenium red and tricomplex flocculation staining indicates that the epithelial surface is coated by saturated phospholipids and mucopolysaccharides. Utilization of various chemical markers demonstrates the epithelial cell to be physiologically active in the transport of certain substances. Evidence supporting the concept that the lamellar inclusion bodies are responsible for the surfactant lining is presented.
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  • 70
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    Cell & tissue research 155 (1974), S. 491-512 
    ISSN: 1432-0878
    Keywords: Gills ; Tilapia mossambica ; Arterio-venous anastomoses ; Specialized endothelia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Arterio-venous anastomoses (AVA) in gill filaments of Tilapia mossambica exhibit a distinct polarity. Two different types of highly specialized endothelial cells, both of epitheloid shape, line these vessels: Type I cells, contacting the arterial lumen, are elongated and about two to three times as large as type II endothelial cells. Their surface is increased by tentacular protrusions which reach far into the arterial lumen. Filament whorls forming tubelike structures with centrally located glycogen granules are abundant in these cells. Type II endothelial cells are located proximal to the central venous sinus (CVS). Their less abundant and more electron dense cytoplasm is free of filament whorls. There are also intermediate cell forms at approximately the middle of each anastomosis. Short cell processes protrude from all endothelial cell types into the AVA lumen. Outside the indistinct vascular basement lamina, a layer of cover cells tightly envelopes the AVA. These cells are, however, absent around the part of the AVA adjacent to the CVS. Here the endothelial cells are in immediate contact with the interstitium. Endothelial cells sheathed by cover cells reach the interstitium through basal foot processes. Nerve fibre bundles regularly come into close contact with the AVAs. Possible functions of the AVAs, including osmoreception are discussed.
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  • 71
    ISSN: 1432-0878
    Keywords: Avian follicles ; Oocytes ; Transosomes ; Lysosomes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy has been utilized to determine fates of sacs of ribosomes (variously termed “transosomes”, “unique organelles”, or “lining bodies”) formed in the follicular cells of avian follicles and subsequently entering-or being taken in-by the oocytes. Small follicles (0.5 mm diameter) of laying hens, a hen afflicted with Marek's disease and prelaying pullets were examined in this regard. In the case of the hen with Marek's disease and the prelaying pullets, sacs of ribosomes were found to be present within the oocyte but those present in the interior of the cell were in the form of digestive vacuoles. In a fourth group of hens, receiving actinomycin D, larger oocytes (2.0 mm diameter) exhibited breakdown of the membranous vesicles in which the sacs of ribosomes entered the oocyte, as well as dissolution of membranes surrounding the forming yolk granules and the membranes of coated vesicles. Annulate lamellae were present in oocytes of the hen afflicted with Marek's disease and appeared within at least 24 hours in oocytes from hens receiving actinomycin D.
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  • 72
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    Cell & tissue research 147 (1974), S. 259-269 
    ISSN: 1432-0878
    Keywords: Nerve endings ; Hair ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Palisade-shaped nerve endings of the small normal hairs of the rat snout were examined with the electron microscope (fixation by perfusion). The terminals are located inside the ‘glassy membrane’ in the area of the neck of the hair root. The 10–20 radially arranged terminal axons are in direct contact with the basement membrane of the epithelium of the external root sheath. The axons are surrounded on all sides by leaf-shaped processes of the Schwann cells. The surfaces of these cell processes are marked by numerous vesicle-like invaginations (approx. 1000 Å dia.). Transverse sections from several areas of the palisadeshaped nerve endings are compared with longitudinal sections. In the upper area ‘empty’ vesicles (approx. 500–600 Å in diameter) occur, along with electron-dense vesicles (approx. 800–1100 Å in diameter); in the middle area, the axons are distended and contain accumulations of mitochondria.
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  • 73
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    Cell & tissue research 148 (1974), S. 1-9 
    ISSN: 1432-0878
    Keywords: Branchiostoma ; Osmoregulation ; Cyrtocytes ; Podocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The excretory organs of Amphioxus occur as segmentally arranged structures throughout the pharyngeal region and may be divided into three components: the solenocytes, the renal tubule, and the renal glomerulus. The solenocytes possess foot processes that rest upon the coelomic surface of the ligamentum denticulatum. The tubular apparatus of the solenocytes consists of ten triangular rods surrounding a central flagellum. The distal end of the tubular apparatus enters branches of the renal tubule. The renal tubule eventually opens into the atrial cavity of Amphioxus. The renal glomerulus is a sinus within the connective tissue of the ligamentum dentieculatum where it connects elements of the branchial circulation with the dorsal aorta. The renal glomerulus, like other blood vessels of Amphioxus, lacks an endothelial lining. If Amphioxus is adapted to artificial sea water at different concentrations there is no change in kidney morphology suggesting that Amphioxus is either is osmotic with its environment or is osmoregulating with other organs.
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  • 74
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    Cell & tissue research 148 (1974), S. 57-67 
    ISSN: 1432-0878
    Keywords: Prostate ; Rat ; Cyproterone ; Alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The dorsal lobe and the coagulating gland of the rat prostate were studied after administration of the anti-androgenic compound Cyp A for varying periods (7–20 days). There was a general involution of the organs with macroscopic atrophy and reduced amount of secretory material. Ultrastructurally the cells were pale, contained less organelles as compared with the controls, loss of cytoplasm and reduction both of cell height and width. The major changes also included reduction of the Golgi area, the rough endoplasmic reticulum and the number of free ribosomes. Within the dorsal lobe prominent nuclear changes were found, comprising different types of intranuclear inclusions of membranous configurations. The alterations observed in the present study are similar to the changes which were found in castrated animals and are consistent with atrophy. The results are discussed in relation to the available biochemical and autoradiographic data on the different lobes.
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  • 75
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    Cell & tissue research 150 (1974), S. 95-105 
    ISSN: 1432-0878
    Keywords: Mucosal mast cells ; Rat ; Compound 48/80 ; Degranulation, Release ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mast cells in the tongue and lamina propria of the duodenal mucosa, representing two cell types with different morphological, histochemical and functional properties have been studied under the electron microscope. Both cell types were found to contain similar moderately electron dense and homogeneous granules surrounded by a tight membrane constituting the basic ultrastructural characteristics of mast cells. The mucosal mast cells, however, contained fewer granules per cell and the individual granules often exhibited considerable variation in size. In addition the mucosal mast cells, unlike those of the tongue, peritoneum and skin, had a smooth plasma membrane lacking microvilli and possessed irregularly shaped or lobulated nuclei. In the tongue mast cells, administration of Compound 48/80 caused the formation of vacuoles around the granules, expulsion of granules from the cells and disintegration of the granular matrix, but no changes that could be attributed to 48/80 could be found in the mucosal mast cells.
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  • 76
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Mitochondria ; ACTH ; Stereology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a chronic administration of ACTH (up to 36 consecutive days) on the mitochondria of the zona fasciculata of the rat adrenal cortex were investigated by stereologic techniques. It was found that, while the volume of the mitochondrial compartment significantly increases in relation to the duration of treatment, the size and number of mitochondria display a different pattern. Up to the 9th day of hormone treatment mitochondria significantly increase in volume, whereas their number per cell is only slightly increased. After 12 days of ACTH-treatment there is a tremendous increase in the number of organelles per cell, resulting in a significant decrease in their average volume. After 24 and 36 consecutive days of treatment the number of mitochondria per cell as well as their average volume both show a slight but significantly constant increase. The hypothesis that ACTH controls the processes of growth and division of adrenal mitochondria is discussed in the light of evidence indicating that mitochondria contain a complete genetic apparatus largely independent of nuclear control.
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  • 77
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    Cell & tissue research 150 (1974), S. 143-145 
    ISSN: 1432-0878
    Keywords: Arteria centralis retinae ; Cat ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Terminal axons emerging from the inner plexiform layer of the cat retina reach the wall of the arteria centralis retinae, as revealed by electron microscopy. Numerous unusually large dense core vesicles (about 1000 Å in diameter), of different electron densities, occur in the varicosities of these axons. These observations may be compatible with the idea of an innervation of the central artery of the retina which is non-autonomic, possibly intrinsic in nature.
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  • 78
    ISSN: 1432-0878
    Keywords: Rat anterior pituitary ; FSH and LH-gonadotrophs ; Luteinizing releasing hormone ; “Signet cells” ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The action of luteinizing releasing hormone (LH-RH) on FSH and LH-gonadotrophs from the anterior pituitary glands of normal rats has been studied with electron microscopy. After 15 min. incubation with LH-RH, LH cells showed secretory granules undergoing exocytosis, but FSH did not appear to release secretory products. On the other hand, incubations with the releasing hormone for 3 and 6 hr stimulated exocytosis from both FSH and LH-gonadotrophs. Of more interest was the finding that FSH cells appeared as typical “signet cells” of castration when glands were incubated for 3 and 6 hr with the releasing hormone. The appearance of such “signet cells” was prevented if puromycin was added to the medium together with LH-RH.
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  • 79
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    Cell & tissue research 150 (1974), S. 231-247 
    ISSN: 1432-0878
    Keywords: Regeneration ; Nerve cells ; Neurosecretion ; Hydra ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Major ultrastructural changes in neurons were studied during sequential periods of hypostomal regeneration in Hydra. Some neurons remain unaffected except that at certain periods following amputation, they become more active in neurosecretory production. Other neurons in various stages of differentiation were also observed. Most emphasis was placed on degenerating neurons showing a loss of organelles and destruction of the perikarya. Certain large, membrane-bounded structures (up to 1.7 μ in diameter) suggested tentatively to be of a lysosomal-like nature, may be partly responsible for the degenerative process. The neurites of these cells first assume a beaded appearance and/or contain bulbous endings. The eventual isolated fragments of neurites contain typical membrane-bounded neurosecretory droplets (850/1700 Å in diameter) which disintegrate forming particulate materials (350 Å in diameter). Following complete disruption of the neurites, some of the granules accumulate in the extracellular spaces before they are disintegrated. From the data presented in this and the preceding paper, it is suggested that these particles, derived from neurosecretory droplets, may be responsible for the stimulation of: 1) interstitial cell differentiation into neurons, 2) the increased activity in neurosecretory production in normal cells, 3) the conspicuous increase in neurite length and consequently the exaggerated degree of anastomosis, and 4) the possible capacity of neurons to regenerate neurites.
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  • 80
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    Cell & tissue research 150 (1974), S. 481-492 
    ISSN: 1432-0878
    Keywords: Seminiferous tubule, ovine ; Lamina propria ; Development ; Endocrine factors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the lamina propria in the ovine seminiferous tubule was studied from 54 days (postcoitum) fetuses up to sexual maturity. In young animals (aged about two months) the effect of hypophysectomy and/or hormones was also analyzed. Initially, large areas of the lamina propria already show signs of morphological differentiation. The non cellular component is a single or sometimes double lamella. Outwardly, the cellular component is represented by rounded connective tissue cells or by elongated cells, exhibiting 80 Å filaments in the cytoplasm and arranged in 3 to 4 layers. By the first week after birth, the non cellular component is formed by 8 to 10 lamellae and the cellular component shows typical contractile cells, the fibroblasts being now located only in the periphery. Basically, the same aspect is found in the adult ram, thus differing from the more extensively studied prototypes of lamina propria architecture of rodents or primates. In as much as the sheep lamina propria differentiates precociously, probably induced by fetal testicular hormones, it is relatively insensitive to hypophysectomy or hormonal substitution. Hypophysectomy and cyproterone acetate administration cause intracytoplasmic lipid deposition in the contractile cells, the other components being not changed. Some questions are raised concerning the role of this peculiar lamina propria in the function of the blood-testis barrier.
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  • 81
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    Cell & tissue research 150 (1974), S. 545-552 
    ISSN: 1432-0878
    Keywords: Skin, rat ; Cytology ; Innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neural elements within the parenchyma of the sebaceous gland have not been reported previously. Nerve endings have been observed only in the connective tissue surrounding the gland or in close association with the undifferentiated basal cells. In this study, electron microscopy revealed the possible presence of nerve endings (or terminal portions of neural elements) in the suprabasal level of functional sebaceous glands of pinnae of white rats. Morphologically, there are two distinct types of nerve endings. Type 1 is bordered by a membrane of relatively irregular contour and contains a single mitochondrion, various-sized vesicles, numerous microtubules, fine neurofilament-like fibrils, and occasional ribosome-like granules. Type II is also bordered by a membrane, but its contour was relatively smooth and rounded. Moreover, Type II contains many mitochondria, varying in size, density, and the arrangement of cristae. While ribosome-like granules are scattered throughout the structure in relative abundance, there are scarcely any fine neurofilament-like fibrils or microtubules. Whether these two structures are sensory or autonomic fibers could not be determined by electron microscopic examination.
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  • 82
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    Cell & tissue research 152 (1974), S. 13-30 
    ISSN: 1432-0878
    Keywords: Human fetal pineal gland ; Development ; Secretion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the pineal gland of 18 human fetuses (crown-rump lengths 30–178 mm) was investigated. The pineal gland exhibits a pyramidal shape and consists of an anterior and posterior lobe. Only one parenchymal cell type, the pinealocyte, was observed. Few neuroblasts were seen between the pinealocytes and in the extended perivascular space. The pinealocytes possess all the organelles necessary for hormone synthesis. No specific secretory granule could be observed. The organ is abundantly vascularized and richly innervated. The morphology of the capillaries indicates the existence of a blood-brain barrier. The ultrastructure of the human fetal pineal gland suggests that the gland has a secretory function in early intrauterine life.
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  • 83
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    Cell & tissue research 152 (1974), S. 51-67 
    ISSN: 1432-0878
    Keywords: Myelin ; Ventral habenular nuclei ; Interpeduncular nucleus ; Rana esculenta ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural analysis of myelin in the ventral habenular and in the interpeduncular nuclei of the adult frog Rana esculenta has been carried out. In the ventral habenular nuclei, in addition to normally myelinated fibres, some myelin irregularities have been observed. They consist of myelin enwrapping the perikarya of some neurons and of isolated flaps of collapsed myelin. In the interpeduncular nucleus numerous myelinated fibres occur but few redundant myelin irregularities have been noticed. The morphological data suggest that myelination of fibres in these sites is due to the spiral wrapping mechanism from a glial cell process while the myelin irregularities described in the ventral habenular nuclei are probably due to membrane synthesis within the cytoplasm of the myelinated neurons and of the oligodendrocytes which are sometimes observed in contact with the ensheathed neurons. In the interpeduncular nucleus myelinated fibres indenting astrocytes and oligodendrocytes have been observed.
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  • 84
    ISSN: 1432-0878
    Keywords: Aedes aegypti ; Midgut epithelium ; Cytology ; Morphometry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Ultrastruktur des Mitteldarmes von Aedes aegypti Weibchen wurde morphometrisch untersucht. Besonderes Interesse lag dabei auf quantitativen Unterschieden im Bau der Epithelzellen eines vorderen (A) und eines hinteren (P) Abschnittes des Mitteldarmes, um jedem dieser beiden Abschnitte bestimmte Funktionen zuordnen zu können. 5 physiologisch verschiedene Stadien wurden verglichen: 1 = unreife Weibchen; 2 = zum 1. Blutmahl (B.M.) bereit; 3 = Verdauung des B.M.; 4 = zum 2. B.M. bereit; 5 = alternde Weibchen. Wenn der Mitteldarm noch nicht funktionsbereit ist (Stadium 1) gleichen sich die Epithelzellen von A und P quantitativ ultrastrukturell. In den folgenden Stadien hingegen werden deutliche Unterschiede sichtbar. Das Zellvolumen und die Kern-Cytoplasma-Relation werden in P generell größer als in A. Parallel dazu nehmen der Mitochondriengehalt und die Oberfläche des rauhen endoplasmatischen Retikulums in P gegenüber A zu. In A entwickeln sich mehr Microvilli, ein extensiveres basales Labyrinth und ein deutliches glattes endoplasmatisches Retikulum. Vergrößerte Cytoplasmavolumina vor allem in den P-Zellen werden 24 Std. nach dem 1. B.M. gefunden (Stadium 3). Parallel dazu erreichen die Volumina der Organellen und/oder ihre Membranoberflächen ebenfalls Maximalwerte. Diese Vergrößerung des gesamten Zell-apparates läßt den Schluß zu, daß während der Blutverdauung die Funktionskapazität des Mitteldarmes erhöht ist. Basierend auf den quantitativ ultrastrukturellen Unterschieden zwischen den Zellen von A und P wurde postuliert, daß dem vorderen Abschnitt des Mitteldarms verstärkte Absorptionsfunktionen zukommen. Dem hinteren Abschnitt hingegen wurden gesteigerte Protein-syntheseleistungen im Zusammenhang mit der Bildung von Verdauungsenzymen zugeordnet. Die vorliegenden Resultate wurden an einem, in Beziehung auf seine Ernährung, spezialisierten Insekt gewonnen (Blutverdauung). Trotzdem scheint die postulierte Zuordnung von Funktionen zu bestimmten Mitteldarmzonen mit dem “secretion—absorption”-Modell (Berridge, 1970) übereinzustimmen.
    Notes: Summary The ultrastructure of the midgut of Aedes aegypti females was investigated by means of morphometric techniques. The interest was focussed on quantitative differences in the composition of epithelial cells between the anterior (A) and posterior (P) part of the midgut. The aim was to attribute defined functions to each of these 2 parts. 5 different physiological stages were compared: 1 = immature female; 2 = ready for first blood meal (b.m.); 3 = digestion of b.m.; 4 = ready for 2nd b.m.; 5 = aging female. Whereas in stage 1, when the gut has not yet reached a functional state the epithelial cells of A and P resemble each other, distinct differences develop in subsequent stages. Generally the cell volume and the nuclear-cytoplasmic ratio become higher in P than in A. Concomitantly the mitochondrial content and the surface area of the rough endoplasmic reticulum are more prominent in P than in A. On the other hand more microvilli, a more extensive basal labyrinth and a well developed smooth endoplasmic reticulum are present in A. Enlarged cytoplasmic volumes, especially high in P, are found 24 h after the first b.m. (stage 3). In accordance with this increase the volume of organelles and/or their membrane surface areas also reach maximal values. This augmentation of the metabolic cell apparatus suggests that during blood digestion the whole organ develops an increased functional capacity. From the quantitative structural differences in A and P we concluded that the A-part of the midgut is especially involved in absorption. To the P-part more protein synthesis may be attributed, thus indicating an enhanced formation of digestive enzymes. Although this study deals with a rather specialised insect (blood digestion), it appears that our hypothesis attributing functions to defined midgut zones, agrees to a certain extent with the “secretion-absorption-model” of Berridge (1970).
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  • 85
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    Cell & tissue research 152 (1974), S. 185-191 
    ISSN: 1432-0878
    Keywords: Laryngeal muscles ; Female tree frog, Hyla arborea arborea (L.) ; Fine structure ; Motor endplates ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The larynx musculature of female tree frogs is very poorly developed compared with that of males. This is probably due to the fact that they are less used; female tree frogs do not produce mating calls. The larynx muscles of the female are composed of fibers with small, medium, and large cross-sections. The distribution of the motor end plates varies correspondingly: in regions with fibers of very small diameter the density of synapses is about 33 times greater than in regions with large fibers. There is also a difference in fine structure between male and female laryngeal muscles. The muscles of females comprise red fibers, white fibers, and various transitional types. The arrangement of the triads and their number per sarcomere is the same in all fiber types. All fibers contain about the same amounts of glycogen, but the fat content varies widely among the different types.
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  • 86
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    Cell & tissue research 152 (1974), S. 467-475 
    ISSN: 1432-0878
    Keywords: Sertoli cell ; Human testis ; Nucleolus ; Nuclear bodies ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the nucleus of human Sertoli cells has been studied in testicular samples from normal adults and patients with hypospermatogenesis or absence of the germinal cell line (Sertoli cell only syndrome). In all cases the ultrastructure of the nuclear structures was alike. The nucleus is irregularly shaped and its membrane presents numerous pores. The inner aspect of the nuclear membrane is electron dense due to the presence of a fibrous lamina. The outer aspect presents a concentric arrangement of 50 Å cytoplasmic filaments. The chromatin is rather dispersed. Some perichromatin granules are found occasionally. The nucleolus is characteristic of human Sertoli cells and displays three clear components. In addition, sphaeridia of at least two principal morphological types were found. Their significance in the cell metabolism as well as relationship to either the nucleolus or the nuclear DNA are discussed. The need for further investigation on the functional meaning of the nuclear organelles of human Sertoli cells is stressed.
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  • 87
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    Cell & tissue research 153 (1974), S. 1-14 
    ISSN: 1432-0878
    Keywords: Graafian follicle (Rabbit) ; Granulosa cells ; Ovulation ; Basement mem-brane ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Membrana granulosa in rabbit Graafian follicles was studied at accurately determined times after an ovulatory dose of human chorionic gonadotrophin (HCG). At 4 and 6 hrs after injection of HCG the granulosa cells were slightly dissociated around the whole follicle. So-called abutment nexuses (gap junctions) had decreased and continued to do so up to ovulation. At 8 hrs after HCG, membrana granulosa had thinned out apically and cell dissociation was even more evident in all parts of the follicle. Granulosa cell projections through the basement membrane were found, and, closer to the time of ovulation, more and larger granulosa cell protrusions penetrated the partly fragmented basement membrane. At 8 hrs spherical inclusions in the granulosa cells, corresponding to so-called annular nexuses, were significantly more numerous than before injection of HCG; the relative amount had more than doubled. Later, the number of annular nexuses decreased. The significance of annular nexuses and their variations is discussed. The decrease in the abutment nexuses probably means a decrease in cohesive force between the granulosa cells and facilitates follicle expansion; moreover, the simultaneous changes in the basement membrane, with more or less open channels into the antrum the last few hours before ovulation, presumably, permit rapid follicle growth by influx of fluid as soon as increased distensibility of the follicle wall allows further expansion without increase in pressure.
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  • 88
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    Cell & tissue research 153 (1974), S. 31-44 
    ISSN: 1432-0878
    Keywords: Graafian follicle (Rabbit) ; Ovulation ; Capillaries ; Intercellular junc-tions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rabbit Graafian follicles are encircled by a capillary network between the theca interna and the avascular membrana granulosa. After injection of an ovulatory dose of human chorionic gonadotrophin (HCG) the theca interna cells showed an increase in the amount of smooth endoplasmic reticulum, lipid droplets and mitochondria with tubular cristae. In addition, considerably more junctions, similar to the abutment nexuses of granulosa cells were found; annular nexuses also appeared. At 4 hours after injection of HCG a prominent oedema was evident in the theca interna layer, particularly in the apical region. Small fenestrations in the endothelium of the blood capillaries increased in amount after HCG injection, and close to the time of ovulation, large gaps or perforations, 1–3 μ in diameter, were found in the thin, distended part of the endothelial cells. The surrounding basement membrane became fragmented and partly lost, so that a seemingly free passage from the capillary lumen to the interstitium was eventually established. Leakage of fluid, causing interstitial oedema, presumably proceeds until the pressure in the pericapillary interstitium has risen to the pressure in the capillaries. Some hours before and up to ovulation the pericapillary interstitium has also broad communications with the cavity of the follicles. Therefore, both pressure and fluid can be passed from the capillaries-via the interstitium-to the follicle antrum. However, influx of fluid with subsequent follicle expansion and ovulation-at constant pressure-does not occur until the tensile strength of the follicle wall has decreased.
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  • 89
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    Cell & tissue research 153 (1974), S. 79-88 
    ISSN: 1432-0878
    Keywords: Yolk nuclei ; Nassarius reticulatus ; Cleavage ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Dotterkerne kommen in allen Blastomeren des 4- bis 16-Zellstadiums von Nassarius vor. Sie haben überwiegend kugelige Gestalt und liegen kernnah zwischen Kern und apikalem Plasmalemm. Feinstrukturell sind sie erstaunlicherweise nicht einheitlich aufgebaut, sondern treten in zwei Typen auf: Typ I besteht aus einer relativ kompakt erscheinenden kugeligen Ansammlung von Mitochondrien. Die Mitochondrien liegen in einer dichten, teils granulären, teils fibrillären intermitochondrialen Substanz eingebettet. Typ II besteht aus einer ebenfalls kugeligen Ansammlung vieler kleiner radiär angeordneter Golgi-Stapel, welche in der gleichen dichten, teils granulären, teils fibrillären Substanz liegen wie die Mitochondrien von Typ I. Die Funktion beider Typen von Dotterkernen wird diskutiert. Sicherlich haben sie nichts mehr mit der Dottersynthese zu tun wie möglicherweise die Dotterkerne der Oocyten, doch gibt es bisher auch keine Anzeichen dafür, daß sie bevorzugt am Dotter- oder Lipidabbau beteiligt sind.
    Notes: Summary In all blastomeres of Nassarius from 4- to 16-cell stage yolk nuclei occur. Most of them are spherical bodies, lying juxtanuclearly between the nucleus and the apical plasmalemma. Strangely they are not ultrastructurally uniform but fall into two categories (Fig. 5): Type I is a massive spherical accumulation of mitochondria embedded in a dense intermitochondrial substance, which appears to contain both granules and filaments. Type II is a ball of radially arranged small Golgi stacks clustered around a centre of Golgi vesicles and other organelles embedded in a ground cytoplasm structurally similar to the intermitochondrial substance of type I. The function of both types of yolk nuclei is unknown. These segmentation yolk nuclei have nothing to do with yolk synthesis any more. On the other hand there are no indications that yolk nuclei occurrence is correlated with the break-down of yolk because neither lipid droplets nor protein yolk granules are observed in or beside the yolk nuclei.
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  • 90
    ISSN: 1432-0878
    Keywords: Synapses ; Embryo (Xenopus laevis) ; Spinal cord ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rostro-caudal gradient of differentiation found in vertebrate embryos has been utilized to examine the sequence of synaptic junction development in the spinal cord of Xenopus laevis at a late embryonic stage. Uniform samples were taken at various points along the cord of a stage 27 embryo and examined in the electron microscope. The general ultrastructure of the cord demonstrated the rostro-caudal gradient of development. The sequence of synaptic junction development was like that in the cervical region (Hayes and Roberts, 1973). “Membrane-vesicle clusters” and “immature” synaptic junctions were found most caudally followed by synaptic junctions, first with cleft and subsynaptic membrane density, then with only cleft density and finally, most rostrally, with cleft, subsynaptic membrane, and subsynaptic cytoplasmic density. Mature synaptic junctions were found in increasing numbers from the mid to anterior trunk cord and could mediate alternating trunk flexions made by the embryos at this stage of development. “Membrane-vesicle clusters” were found near processes containing irregular vesicles and also near membrane outlines. These may be signs of dendritic growth. “Membrane-vesicle clusters” were also found in varicosities, facing the space around the spinal cord and in nerve fibres peripherally between the skin and myotomes. This suggests an association of early stages in synaptogenesis with axon growth. This and other possible inferences about axon and dendrite growth in relation to synaptogenesis are discussed.
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  • 91
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    Cell & tissue research 154 (1974), S. 303-319 
    ISSN: 1432-0878
    Keywords: Carotid body (Cat) ; Chemoreceptor ; Nerve endings ; Glossopharyngeal nerve ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of nerve endings in the cat carotid body was analyzed by serial section electron microscopy. In the normal animal, three types of intralobular endings can be recognized. The first type consists of large, calyciform endings which surround glomus cells. The second type includes small calyciform endings which arise from a thin axon and also contact glomus cells. Interstitial enlargements enveloped by sustentacular cells having no direct contact with glomus cells constitute a third type of nerve ending. Intracranial section of the glossopharyngeal nerve caused no change in the number or appearance of intralobular endings, indicating that they are afferent terminals. Stromal axons in the connective tissue of the carotid body may be autonomicfibers as indicated by their degeneration following removal of the superior cervical ganglion.
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  • 92
    ISSN: 1432-0878
    Keywords: Urinary bladder ; Frog ; Water permeability and Ultrastructure ; Hyperosmolarity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Resumé Certaines informations récentes (voir introduction) nous ont conduits à reconsidérer la possibilité que l'action de l'hormone antidiurétique sur les tissus épithéliaux puisse s'exercer au niveau des jonctions intercellulaires. Une étude comparative des cinétiques d'apparition des altérations ultrastructurales et des variations de perméabilité à l'eau a permis d'établir que les décollements de la “tight junction” provoqués par l'hyperosmolarité muqueuse apparaissent avant tout accroissement significatif du flux net d'eau et ne peuvent donc pas en être la conséquence. L'examen à haute résolution, par cryodécapage, de la structure de la “tight junction” montre l'apparition dans ces conditions de plages plus ou moins circulaires où la membrane présente un aspect lisse et apparemment distendu et où la structure typique de la “tight junction” a disparu. Ces modifications rétrocèdent après stimulation hormonale et ceci conduit à penser qu'elles ne sont pas impliquées dans la réspone hydrosomotique physiologique.
    Notes: Summary The role of the tight junction in the hydrosmotic response of the frog urinary bladder has been analysed by comparative kinetic studies and freeze etching examination. The comparison of the time course of the variations in transepithelial water net flux and of the alterations of tight junction ultrastructure in bladders exposed to mucosal hyperosmolar solutions shows that blisters are present in the tight junction before any increase in transepithelial water net flux. This indicates that the two phenomena are dissociated. In the same experimental conditions, freeze etching examination shows the presence in the tight junction of large areas of smooth and apparently stretched membrane where the typical network structure has disappeared. These alterations are reduced by further treatment with oxytocin and are probably not involved in the physiological hydrosomotic response.
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  • 93
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    Cell & tissue research 154 (1974), S. 543-545 
    ISSN: 1432-0878
    Keywords: Epitheliomuscular cells ; Brachiopoda Lingula ; Acrania ; Branchiostoma ; Phylogeny ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Epitheliomuscular cells largely corresponding to those of cnidarians have been found in the mesenteria of Lingula and in various coelomic channels of Branchiostoma. They are characterized by basal extensions containing thin and thick myofilaments. In Lingula they also bear an apical cilium.
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  • 94
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    Cell & tissue research 155 (1974), S. 47-55 
    ISSN: 1432-0878
    Keywords: Thymus (human) ; Reticulum cells ; Thymus dependent region ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Seven thymuses from children between 1 and 12 years were examined by electron microscopy. Biopsies had been taken during surgical correction of congenital heart defects. In all cases we found interdigitating reticulum cells (IRC) in the medulla and inner cortex. These cells resembled the IRC which have been described previously in the thymus-dependent regions of the spleen and lymph node. They were characterized by an irregularly shaped nucleus, narrow cisterns of rough endoplasmic reticulum, and widespread interdigitation and invagination of the cell membrane. The surfaces of the IRC were in close contact with those of small lymphocytes, sometimes polysomal lymphatic cells, epithelial cells, and occasionally with those of lymphatic cells containing ergastoplasm. The IRC is apparently a specific cell of thymus-dependent regions. It may be that the IRC in the thymus, lymph node, and spleen contribute to the microenvironment needed for the differentiation of T-cells.
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  • 95
    ISSN: 1432-0878
    Keywords: Salivary glands ; Drosophila ; larval and prepupal ; Electron microscopy ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A major function of the larval salivary glands of Drosophila melanogaster is known to be the production of a mucopolysaccharide that serves as an adhesive during puparium formation. In order to localize the mucosubstances during development substrate histochemical methods were used, and the site of acid phosphatase was demonstrated by the ultrahistochemical lead-salt method. It could be shown that the “glue”-granules in the corpus cells of larval salivary glands as well as the large secretion vacuoles in the prepupal corpus cells give a positive β-amylase-resistent PAS-reaction, which indicates neutral mucosubstances. Granular PAS-positive deposits in the larval and prepupal collum cells were reduced after preincubation with β-amylase and may represent glycogen, which has also been seen in electron micrographs of these cells. The Hale-reaction gave a weak indication that acid mucosubstances are present in the larval “glue” granules and in the large prepupal secretory vacuoles. After digestion of sialic acid with α-neuraminidase the weak indication was absent showing that the acid mucosubstances had been sialomucines. Ultrahistochemical demonstration of acid phosphatase indicated the presence of this enzyme in Golgi fields and lysosomal structures. Acid phosphatase seems to be missing in the large secretion vacuoles of the prepupal salivary gland. It is concluded, that the large vacuoles in the corpus cells of prepupal salivary glands represent a secretion product, obviously a mucosubstance. The lysosomal structures, containing acid phosphatase, may be accumulated in preparation for the autolysis of the gland which begins about two hours after the pupal moult, i.e. 15 hours after puparium formation.
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  • 96
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    Cell & tissue research 155 (1974), S. 127-134 
    ISSN: 1432-0878
    Keywords: Organ of Bellonci ; Carcinus maenas (Crustacea, Decapoda) ; Sensory and secretory function ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The organ of Bellonci of Carcinus maenas is made up of onion bodies and secretory cells. The onion body consists of a distal segment, of membranous whorls and granules, and a proximal nuclear cell body. They are joined by a modified double ciliary junction. Both a sensory and secrtory function is suggested. The secretory cells fall into two groups based on size, shape and organelles. Their presence suggests a secretory function to the organ of Bellonci.
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  • 97
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Man ; Primary cultures ; ACTH ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A method of primary tissue culture involving both disaggregation of cells by repeated exposure of small tissue fragments to a solution of trypsin, collagenase and hyaluronidase and explantation of the residual tissue fragments intermingled with isolated cells onto polyethylene discs, has been shown to be adequate for the prolonged maintenance (up to 30 days) in vitro of cells arising from decapsulated adult human adrenocortical tissue. The technique and its critical points are discussed. Adrenocortical cells were organized both as outgrowing columns from microexplants or as variously sized islets of monolayered cells. The ultrastructural features of ACTH-deprived adrenocortical cells (i.e., mitochondria with laminar cristae, endoplasmic reticulum mainly consisting of rough profiles, abundance of lipid droplets and β-glycogen particles) suggest that the cells dedifferentiate and retain practically no steroidogenic activity. After 2 days of ACTH-treatment, cultured parenchymal cells were found to be quite similar to the zona fasciculata elements of the normal human adrenal cortex. They were grouped in islets of about 50–100 cells. Rough endoplasmic reticulum had decreased, but smooth endoplasmic reticulum showed focal proliferation. The pleomorphic mitochondria with laminar cristae, transformed into a homogeneous population of round or ovoid mitochondria containing tubulo-vesicular cristae. Lipid droplets and glycogen particles were decreased in number. After 7 days of daily treatment with ACTH, the cortical elements, whose nucleus and cytoplasm seemed to be enlarged, were arranged in clusters formed by up to 300 monolayered elements, in which dividing cells were consistently observed. Their cytoplasm was filled with a meshwork of smooth reticulum tubules, in which scantly ribosome-studded profiles and occasional small stacks of granular cisternae were embedded. Mitochondria were similar to those of the 2 days ACTH-treated cultures. Lipid droplets and glycogen particles were absent. The functional significance of these structural changes as well as the possible mechanism underlying the differentiative effect of ACTH are discussed. Primary cultures of human adult adrenals are proposed as a new tool for studies into the physiopathology of the adrenocortical cells under carefully controlled experimental conditions. mis|It is a pleasure to acknowledge our thanks to Drs. F. Mantero and C. Eccher for kindly supplying the normal human adrenocortical tissue. Thanks are also due to Mr. G. Gottardo for his excellent technical assistance. mis|This work was partly supported by a contract with the CNR-Italy (C.T. 73.00663.04).
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  • 98
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    Cell & tissue research 155 (1974), S. 193-199 
    ISSN: 1432-0878
    Keywords: Microfilaments ; Prolactin cells ; Anterior pituitary ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prolactin cells from anterior pituitary glands of normal non-lactating female rats, and lactating animals, some of which were separated from their pups for 48 hours, were examined ultrastructurally for the presence of microfilaments. Microfilaments were found in specific intracellular locations in all cells examined. They were in association with the nuclear envelope, the Golgi complex, the endoplasmic reticulum, small vesicles of the endoplasmic reticulum, and secretory granules. The possible role of microfilaments in the movement of intracellular organelles is considered.
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  • 99
    ISSN: 1432-0878
    Keywords: Neuromuscular junctions ; Development in vitro ; Electron microscopy ; Electrophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of neuro-muscular junctions between previously dissociated foetal rat spinal cord and somatic muscle has been investigated. The first indications of junction formation, both ultrastructurally and electrophysiologically, were observed after circa 18 days in vitro. The junctions contained numerous vesicles, but no secondary folds were developed even after 6 weeks in culture, and synaptic densities were not well marked. Functional endplates were found, and action potentials, endplate potentials and miniature endplate potentials recorded.
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  • 100
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    Cell & tissue research 155 (1974), S. 383-398 
    ISSN: 1432-0878
    Keywords: Pigment cells ; Melanin granules ; Pigment retina ; Albino goldfish ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structural differentiation of the retinal pigment epithelium of the albino goldfish (Carassius auratus) in several developmental stages and in the adult was studied. In the 5-mm larva, the retinal pigment cells contained granules whose cores are filled with conglomerates of electron-dense pigments, but they were never pigmented fully as in the control black moor goldfish. Most of the granules have a round or ovoid shape, but granules with an elongate, cigar-like form are occasionally observed. The internal membranous frame-work, which has been reported in unpigmented and lightly pigmented granules in melanocytes of other vertebrates, was rarely observed in the present study. The number of pigment granules increased during the early developmental stages, whereas they decreased conspicuously in the later stages. From these results, the function of one of the albino genes p, is discussed and the following three phenomena are attributed to it: the decrease in formation of cigar-shaped granules, the partial inhibition of pigmentation, and the disintegration of pigment granules during the larval and post-larval stages. In addition to the pigment granules, the differentiation and disappearance of other characteristic cytoplasmic organelles are described. The biological significance of the changes in many of these organelles remains in question.
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