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  • 1995-1999  (38)
  • 1985-1989  (178)
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  • 1998  (38)
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  • Ultrastructure
  • 1
    ISSN: 1432-2307
    Keywords: Key words Apoptosis ; Crescent-shaped spaces ; Ultrastructure ; Nivalenol ; Thymus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  There have been many reports on the formation of apoptotic bodies, but little is known about the cellular pathological processes and the morphological changes involved. We induced apoptotic cell death by administering nivalenol (NIV), a trichothecene mycotoxin produced by Fusarium species, and investigated the ultrastructural process of formation of apoptotic bodies. The thymus was examined by electron microscopy 6, 12, and 18 h after administration. Apoptotic cell death was induced in the thymus of NIV-treated mice. The nuclei became invaginated and pinched off to give fragments, and crescent-shaped spaces (CSS) were found around the nuclear envelopes of these cells at quite an early stage. In some of these spaces, myelin figures were observed. We divided the process of formation into four stages and characterized each of them. These are easily recognized in morphological stages and are also useful for clarifying the apoptotic mechanism.
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  • 2
    ISSN: 1432-0533
    Keywords: Key words Brittany Spaniel dog ; Immunocytochemistry ; Purkinje cell ; Spinocerebellar degeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Eight Brittany Spaniel dogs, seven females and one male, between 7 and 14 years old presented with clinical neurological signs of spinocerebellar disease of about 6 months to 4 years duration. Clinically the dogs had a dramatic forward “saluting” movement of the thoracic limbs, hypermetria of the pelvic limbs, cerebellar ataxia and intention tremors. Terminally, dogs crawled in a crouched thoracic posture with neck extension. Lesions were confined to cerebellum, medulla oblongata and spinal cord. The most severe lesion was diffuse Purkinje cell loss with massive neurofilament accumulation in degenerating cells. There was some bilateral neuronal degeneration in the dorsal horns of the spinal cord and in the gracilis and cuneate nuclei. There was bilateral sporadic axonal degeneration in the dorsal columns and lateral and ventromedial areas of the spinal cord. The etiology of this syndrome was not determined.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 95 (1998), S. 367-372 
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; Heterotopic neuron ; Alpha motor neuron ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns a comparative immunocytochemical, ultrastructural and morphometric investigation on heterotopic neurons in the white matter of the spinal cords of 19 patients with amyotrophic lateral sclerosis (ALS) and 18 age-matched neurologically normal individuals. The study revealed that the heterotopic neurons were scattered in the white matter, often adjacent to gray matter, that they immunoreacted with the antibody to synaptophysin, and that there were synaptic apparatuses on the surface of their somata and their neuronal processes. Bunina bodies and ubiquitin-positive inclusions such as Lewy body-like inclusions and skein-like inclusions, characteristic of anterior horn neurons of ALS, were present in the cytoplasm of the patients’ heterotopic neurons in the anterior or lateral column of the white matter. These findings suggest that heterotopic neurons in the anterior or lateral column have the characteristics of alpha motor neurons. The average number of heterotopic neurons observed in ALS patients was generally less than in normal subjects. This reduction was correlated with the severity of neuronal loss. The heterotopic neurons in ALS were less susceptible to the degenerative process as compared with spinal cord anterior horn cells. We assume that in this disease the heterotopic neurons may be degenerated and their number diminished after or concomitantly with the depletion of anterior horn neurons.
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  • 4
    ISSN: 1432-0533
    Keywords: Key words Dentatorubral-pallidoluysian atrophy ; Nuclear inclusion ; Ubiquitin ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the brains and spinal cords of seven patients with clinicopathologically and genetically confirmed hereditary dentatorubral-pallidoluysian atrophy (DRPLA) using an antibody against ubiquitin, and found small, round immunoreactive intranuclear inclusions in both neurons and glial cells in various brain regions. Ubiquitinated neuronal intranuclear inclusions (uNIIs) were consistently found in the striatum, the pontine nuclei, the inferior olivary complex, the cerebellar cortex and the dentate nucleus. Ubiquitinated glial intranuclear inclusions (uGIIs) were found less frequently than uNIIs. Most of the inclusion-bearing nuclei were of an astrocytic nature. Immunostaining with an antibody against DRPLA protein revealed similar immunoreactive neuronal and glial intranuclear inclusions, but in much smaller in numbers compared with uNIIs and uGIIs. Electron microscopy showed that such inclusions were composed of granular and filamentous structures. These findings strongly suggest that, in DRPLA, the occurrence of uNIIs and uGIIs is directly related to the causative gene abnormality (an expanded CAG repeat encoding polyglutamine), that neurons are affected much more widely than previously recognized and that glial cells are also involved in the disease process.
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  • 5
    ISSN: 1432-0533
    Keywords: Key words Congenital myopathy ; Muscle fibers ; Ultrastructure ; Myofibrillar disarray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 44-year-old man presenting with dyspnoic attacks was found to be affected with congenital myopathy, rigid spine, restrictive respiratory insufficiency and cardiomyopathy. Muscle biopsy showed type 1 fiber predominance (65.7%) and hypotrophy, and characteristic changes in 43.9% of the type 1 fibers, consisting in alternating pale and dark staining on alkaline ATPase reacted sections in a mosaic pattern. Ultrastructural examination demonstrated bands of myofibrils at right angles or skew to the remaining myofibrils transversing the fibers. Myofibrillar disarray was always associated with loss of the Z-discs and actin filaments, and often with aggregation of mitochondria. The muscle biopsy findings in this patient suggest a new entity of congenital myopathy with clinical features of rigid spine, cardiomyopathy and restrictive respiratory insufficiency, characterized by peculiar abnormalities of ATPase staining in a mosaic pattern and, ultrastructurally, by zones of disorientation of the sarcomeres.
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  • 6
    ISSN: 1432-0568
    Keywords: Key words Adult-type Leydig cells ; Endothelium ; 3β-HSD ; Ultrastructure ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In the biosynthesis of steroid hormones 3β-hydroxysteroid dehydrogenase (3β-HSD) is a key enzyme. The present report describes the subcellular localization of the enzyme in the fetal-type Leydig cells, the fibroblast-like precursors of adult-type Leydig cells and in endothelial cells of interstitial capillaries. Histochemical methods for light microscopy and ultracytochemical methods for electron microscopy were used on rat testes of postnatal day 15. 3β-HSD reactivity was located at subcellular levels by means of the ferricyanide method. A specific, distinct localization of reaction product in the form of copper ferrocyanide precipitates was observed on the membranes of the smooth endoplasmic reticulum not only in the fetal-type Leydig cells and the fibroblast-like precursors of adult-type Leydig cells, but also focally in the endothelial cells of interstitial blood capillaries. Topographically, the 3β-HSD-positive precursors were most often found in the outer layer of the boundary tissue and surrounding interstitial blood vessels. The capillaries with 3β-HSD-positive endothelial cells were usually located in the vicinity of 3β-HSD-positive Leydig cells. For the first time, 3β-HSD has been located at the subcellular level in precursors of adult-type Leydig cells and focally in capillary endothelial cells associated with them. Due to the close association between 3β-HSD-positive vascular endothelial cells and Leydig cells a paracrine relationship between the two cell types may be involved in the acute regulation of steroidogenesis by blood-borne luteinizing hormone.
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  • 7
    ISSN: 1432-0533
    Keywords: Key words Anorexia nervosa ; Myopathy ; Muscle biopsy ; Ultrastructure ; Protein-energy malnutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Protein-energy malnutrition in anorexia nervosa is an under-recognised cause of muscle dysfunction. To characterise the skeletal myopathy that occurs in patients with severe anorexia nervosa, muscle function and structure were comprehensively examined in eight young adult female patients with severe (40%) self-induced weight loss. All of the patients showed impaired muscle function on strength and exercise measurement. The maximum voluntary contraction force for the patient group was significantly less than predicted values. Electromyography revealed myopathy in five of the patients, four of whom also had electro-physiological evidence of neuropathy. However, muscle biopsy specimens consistently showed myopathic changes with severe type 2 fibre atrophy but with no evidence of neuropathic changes. Ultrastructurally, there was separation and segmental loss of myofibrils and most biopsy samples contained abundant glycogen granules; we have previously reported that one of the most consistent biochemical abnormalities in these patients is impaired ischaemic lactate responses to forearm exercise. The result of severe protein-energy malnutrition on the musculo-skeletal system is a metabolic myopathy. Although the patients admitted to a variety of abnormal dieting behaviours, such as over-exercising and self-induced vomiting, no association was found between any of these and quantitative histological changes in the muscle biopsy samples. It is recommended that myopathy in anorexia nervosa be treated by instituting an appropriate refeeding programme.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 197 (1998), S. 135-141 
    ISSN: 1432-0568
    Keywords: Key words Interstitial cells of Cajal ; Ultrastructure ; Gap junction ; Intestine ; Motility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Interstitial cells forming many large gap junctions in the region of the deep muscular plexus of the rat small intestine were studied by electron microscopy and by three-dimensional cell models reconstructed from serial ultrathin sections. Two different profiles of cells were observed. Cells of the first profile are characterized by an elongated cell shape and by less electron-dense cytoplasm, containing many mitochondria, well-developed Golgi apparatus and free ribosomes. They mainly connect with smooth muscle cells of the main circular layer. In a three-dimensional cell model, the total area of the gap junctions occupies 1.3% of the cell surface. Cells of the second profile are characterized by the frequent occurrence of slender cytoplasmic processes, higher electron-dense cytoplasm, containing mitochondria, Golgie apparatus and well-developed rough endoplasmic reticulum, and numerous caveolae on the cell membrane. In this cell model, gap junctions occupy 0.8% of the cell surface. The ratio of gap junctions with the same profile of cells to the total gap junction area is 37.7%, which is more than three times greater than the 9.9% in cells of the first profile. These cells were closely associated with nerve terminals. It is likely that these cells with different profiles constitute subtypes with each other and cooperate for regulation of intestinal motility via the transmission of nerve signals.
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  • 9
    ISSN: 1432-0533
    Keywords: Key words Congenital myopathy ; morphometry ; Ultrastructure ; Fetal myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Centronuclear myopathy (CNM) is a congenital myopathy which manifests itself as a severe neonatal (also termed myotubular myopathy), early-onset, or adult form. The histological pattern of each is marked by a considerable number of nuclei of muscle fibers being internally placed. Owing to their remote resemblance to myotubes, and their expression of developmentally regulated proteins, most authors now favor the concept that myogenesis is arrested or delayed in this disease. We here present two muscle biopsy specimens of a patient with early-onset CNM, taken at the age of 5 months and 14 years, respectively. The first biopsy sample contained internally placed nuclei in 7% of the muscle fibers, abundant minute myotubes, and hypertrophic muscle fibers. The second biopsy sample showed internally placed nuclei in 40% of the muscle fibers, and hypotrophic fibers. We suggest that the histological findings in early-onset CNM are the result of a complex dynamic process, which includes a delay in maturation.
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  • 10
    ISSN: 1432-0533
    Keywords: Key words Aging ; Blood-brain barrier ; Horseradish peroxidase ; Senescence-accelerated mouse ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructural features of microvessels showing increased permeability to intravenously injected horseradish peroxidase (HRP) were examined in the olfactory bulbs of senescence-accelerated prone mice (SAMP8), which showed age-related deficits in learning and memory, and senescence-accelerated resistant mice (SAMR1), which did not show the age-related deficits. HRP was visualized with tetramethyl benzidine (TMB) and diaminobenzidine (DAB) for light and electron microscopic examination, respectively. In the olfactory bulbs of 13-month-old SAMP8 mice, the staining reaction with TMB for HRP appeared in the neuropil of central area (granule cell layer and subependymal layer), in the pia mater and in the vascular wall. Some vessels located in the central area showed several changes observed at the ultrastructural level. The cytoplasm of the endothelial cells, especially in the arterioles, was segmentally thickened and contained numerous vesicles and vacuoles, some of which were HRP positive. The endothelial cell surface was occasionally undulated with microvillous protrusions. Membranous inclusions within the basal lamina, suggesting the cellular (presumably pericytal) degeneration, were frequently observed, especially in venules. The collagen deposits were occasionally observed in the subendothelial space of some vessels. Perivascular cells with vacuolated inclusions or lipid-like droplets were present around some vessels in the central area of the olfactory bulbs of aged SAMP8 mice. On the other hand, in the microvessels located in the areas negative for HRP-TMB reaction, except the vessel walls, the cytoplasm of the endothelial cells with smooth luminal surface was flattened and some vesicles located there contained HRP-DAB reaction product. Weak staining reaction with TMB for HRP appeared also in the central area of the olfactory bulbs of 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. The cytoplasm of the endothelial cells in the olfactory bulbs of these mice was focally thickened and contained some cytoplasmic vesicles. Occasionally, the endothelial cell surface was moderately undulated with few microvillous protrusions. Membranous inclusions within the basal lamina were not observed in these animals. These findings indicate that the endothelial cells and pericytes in some vessels located in the central area of the olfactory bulb of aged SAMP8 mice, which show staining reaction with TMB for HRP, are ultrastructurally changed, suggesting their altered functions.
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  • 11
    ISSN: 1432-069X
    Keywords: Key words Barrier function ; pH ; Stratum corneum ; Lamellar body ; Lipid content ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Epidermal permeability barrier homeostasis requires the postsecretory processing of polar lipid precursors into nonpolar lipid products within the stratum corneum (SC) interstices by a family of lipid hydrolases. A specific requirement for β-glucocerebrosidase (β-GlcCer’ase), which exhibits a distinct acidic pH optimum, is particularly well documented. Therefore, we sought to determine whether the recovery of the barrier after acute insults requires acidification of the SC. We examined permeability barrier recovery by assessing changes in transepidermal water loss (TEWL), SC membrane ultrastructure utilizing ruthenium tetroxide (RuO 4 ) postfixation, and β-GlcCer’ase activity by in situ zymography at an acidic vs neutral pH. Barrier recovery proceeded normally when acetone-treated skin was exposed to solutions buffered to an acidic pH. In contrast, the initiation of barrier recovery was slowed when treated skin was exposed to neutral or alkaline pH, regardless of buffer composition. In addition, enhancement of the alkaline buffer-induced delay in barrier recovery occurred with Ca 2+ and K + inclusion in the buffer. Moreover, the pH-dependent alteration in barrier recovery appeared to occur through a mechanism that was independent of Ca 2+ - or K + -controlled lamellar body secretion, since both the formation and secretion of lamellar bodies proceeded comparably at pH 5.5 and pH 7.4. In contrast, exposure to pH 7.4 (but not pH 5.5) resulted in both the persistence of immature, extracellular lamellar membrane structures, and a marked decrease in the in situ activity of β-GlcCer’ase. These results suggest first that an acidic extracellular pH is necessary for the initiation of barrier recovery, and second that the delay in barrier recovery is a consequence of inhibition of postsecretory lipid processing.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Zeitschrift für Lebensmittel-Untersuchung und -Forschung 206 (1998), S. 38-43 
    ISSN: 1431-4630
    Keywords: Key words Starch ; Gels ; Kamaboko ; Surimi ; Gelatinization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The purpose of this work was to study the changes undergone by starch during heat-induced surimi gel preparation either with or without added egg white, and their effects on the structure of gels using light and scanning electron microscopy. Gels were made from SA-grade Alaska pollack (Theragra chalcogramma) surimi with: (1) salt (3%, w/w); (2) salt and waxy corn starch (3% and 5%, respectively w/w); or (3) salt, waxy corn starch and egg white (3%, 5% and 5%, respectively, w/w). Final moisture was adjusted to 73% or 83%. The gels were prepared by prior setting (40°C, 30 min, followed by 90°C, 30 min) or cooking (90°C, 30 min). The prepared gel was frozen and stored at –20°C (±1°C) until analysis. Samples were observed by light and scanning electron microscopy. The results show that the starch granules alter according to the processing conditions, with the predominance of crystalline or amorphous morphology depending upon the availability of heat and water. Large cavities formed in the protein gel matrix during setting can trap water; as a result, water availability is limited for starch to swell and gelatinize even in the high-moisture gel.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 19 (1998), S. 373-378 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Metaplastische Brustdrüsenkarzinome ; Plattenepithelmetaplasie ; Plattenepithelkarzinom ; Immunhistologie ; Elektronenmikroskopie ; Zytophotometrie ; Key words Pure squamous cell carcinoma ; Mammary gland ; Squamous metaplasia ; Immunohistology ; Cytophotometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Squamous metaplasia can be demonstrated in about 4% of all invasive carcinomas of the breast. Primary squamous cell carcinomas of the breast are rare, since they occur in less than 1% of all primary invasive breast carcinomas. In order to classify a breast tumor as a primary squamous cell carcinoma one must exclude an epidermal origin, especially from the nipple region and the possibility of metastatic infiltration of the breast by a squamous cell carcnoma from a different location. Causative and formal pathogenesis of primary squamous cell carcinoma of the breast is not clear. A pluripotent embryonal stem cell origin is discussed, considering the phylogenetic descent of the mammary gland from skin appendages. Squamous metaplasia is also suggested to be a precursor of squamous cell carcinoma. Here endocrine stimulation and chronic inflammation may both play an inductive role. The number of published cases of squamous cell carcinomas developing years and decades after implantation of silicon prostheses has increased in recent years. These tumors probably develop on top of squamous metaplasia induced by the inflammatory pseudocapsule. Estimating the prognosis and therapeutic management in patients with squamous cell carcinoma of the breast should follow the same guidelines as for other squamous cell cancers.
    Notes: Zusammenfassung Plattenepithelmetaplasien werden bei etwa 4% aller invasiven Brustdrüsenkarzinome beschrieben. Reine Plattenepithelkarzinome der weiblichen Brustdrüse sind mit einem Anteil von wahrscheinlich unter 1% an allen invasiven epithelialen Tumoren der Mamma selten. Von einem primären Plattenepithelkarzinom der Brustdrüse darf nur gesprochen werden, wenn zum einen der Ursprung von der Epidermis, insbesondere auch im Bereich des Mamillentrichters ausgeschlossen ist und zum anderen keine metastatische Infiltration in die Brustdrüse durch ein Plattenepithelkarzinom anderer Organlokalisation vorliegt. Die kausale und formale Pathogenese der primären Plattenepithelkarzinome der Brustdrüse ist unklar. Zum einen wird ein Ursprung von pluripotenten embryonalen Stammzellen diskutiert, wobei bedacht wird, daß die Brustdrüse entwicklungsgeschichtlich ein Hautanhangsgebilde darstellt. Zum anderen werden Plattenepithelmetaplasien als Vorstufe der Plattenepithelkarzinome diskutiert, wobei neben einer endokrinen Induktion auch länger bestehende Entzündungsreize eine Rolle spielen sollen. In den letzten Jahren wird immer häufiger darüber berichtet, daß oft Jahrzehnte nach Implantation von Silikonprothesen periprothetische Plattenepithelkarzinome entstehen, die wahrscheinlich über die Stufe einer Plattenepithelmetaplasie der entzündlichen Prothesenpseudokapsel entstehen. Die Abschätzung der Prognose und therapeutische Maßnahmen bei primären Plattenepithelkarzinomen der Brustdrüse sollten an den Erfahrungen mit Plattenepithelkarzinomen anderer Organlokalisation ausgerichtet werden.
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  • 14
    ISSN: 1432-2145
    Keywords: Key words Abies ; Egg cell ; Plastid inheritance ; RFLP ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The ultrastructure of egg cells in Abies alba was examined to elucidate the lack of maternal inheritance of plastids. Before fertilization, maternal plastids are absent in the perinuclar zone containing mainly mitochondria and smooth endoplasmic reticulum. During egg cell development the maternal plastids are transformed into large inclusions which are situated mostly towards the periphery of the egg cell, and finally disintegrate. As a consequence, they do not participate in zygote formation. RFLP analysis of cpDNA of parental trees and their F1 interspecific hybrids (A. alba×A. numidica, A. alba×A. nordmanniana, A. nordmanniana×A. Alba) using HindIII and BamHI showed a paternal mode of cpDNA inheritance. Paternal inheritance has also been found with PCR/RFLP analysis of cpDNA from parental trees and their hybrids (A. alba×A. pinsapo, A. pinsapo×A. alba, A. pinsapo×A. numidica) using ApaI and HaeIII digests, as well as in the crosses of A. cephalonica×A. nordmanniana, A. nordmanniana×A. cephalonica, A. cephalonica×A. numidica using TagI digests.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Sexual plant reproduction 11 (1998), S. 121-130 
    ISSN: 1432-2145
    Keywords: Key words Egg cell ; Parthenogenesis ; Synergid ; Ultrastructure ; Wheat ; Zygote
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The ultrastructure of the egg apparatus of the sexual (aestivum)-Salmon line (aS) and the isogenic but alloplasmic (kotschyi)-Salmon line (kS) of the Salmon system of wheat was studied by transmission electron microscopy 3 days before and during anthesis. Additionally, the zygotic stage of aS, 17 h after pollination, was included. Metabolic activity of egg cells from the sexual line aS was low 3 days before anthesis and increased dramatically after pollination and fertilization. This timing of increased activity was evident because of changes occurring in the egg cell nucleus and nucleolus, polysomes, endoplasmic reticulum and Golgi apparatus, and the completion of the cell wall around the zygote. In contrast to the sexual line, the egg cell of the parthenogenetic line showed high activity 3 days before anthesis. The metabolic and ultrastructural characters observed in the nucleus and cytoplasm of the kS line 3 days before and during anthesis corresponded with those of the isogenic sexual line aS during anthesis and 17 h after pollination, respectively. High metabolic activity observed in the persistent synergid of kS may be connected with the occurrence of additional embryos in seeds (twins) of this line.
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  • 16
    ISSN: 1432-072X
    Keywords: Key words Magnetic bacteria ; Biomineralization ; Magnetite ; 16S rRNA ; In situ hybridization ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Natural enrichments of magnetic bacteria from the Itaipu lagoon near Rio de Janeiro were dominated by coccoid-to-ovoid morphotypes that produced unusually large magnetosomes. To determine the phylogenetic position of these unusual microorganisms, 16S rRNA genes were retrieved from bacteria magnetically separated from sediment of the Itaipu lagoon by in vitro amplification and cloning of PCR products into a plasmid vector. Partial sequencing of the obtained clones revealed two clusters of closely related sequences affiliated to a distinct lineage consisting exclusively of magnetic bacteria within the α-subclass of Proteobacteria. For a detailed phylogenetic analysis, several almost complete sequences of the 16S rRNA genes were determined. One representative clone of each cluster provided a PCR template for the in vitro transcription of group-specific polynucleotide probes complementary to a variable region of the 16S rRNA molecule. At least three different morphotypes of magnetic bacteria were reliably identified by post-embedding hybridization of ultra-thin sections. Electron microscopic analyses of hybridized cells enabled for the first time a detailed description of the morphological variety and ultrastructure of phylogenetically identified, uncultured magnetic bacteria. Two distinct coccoid bacteria were identified by the transcript probe complementary to the 16S rRNA sequence mabrj12, whereas the probe complementary to the sequence mabrj58 allowed the identification of an ovoid morphotype that displayed magnetosomes with the largest volumes observed to date.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 292 (1998), S. 275-282 
    ISSN: 1432-0878
    Keywords: Key words Interstitial cells (Cajal) ; Large intestine ; Fluorescent dyes ; Vital staining ; Ultrastructure ; Mouse (BALB/c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Interstitial cells of Cajal (ICCs) are believed to be a major element in generating the spontaneous rhythm of the gastrointestinal tract. A prominent problem in the study of these cells has been the difficulty in observing them in intact tissues. We used the lipophilic dye DiI to stain ICCs in the submucosal-circular muscle border of freshly dissected mouse colon. The placement of small DiI crystals in this area resulted in the labeling of ICC-like cells. Two main morphological cell types, viz., bipolar and multipolar, were noted. Bipolar cells had two primary processes emerging from the poles of an elongated soma. The mean length of these processes was 78.7 μm. These cells constituted 42.3% of the sample (n=105). Multipolar cells (54.3% of total) had a less elongated soma and extended 3–6 main processes whose mean length was 56.3 μm. These processes showed no preferred direction. The length of the primary processes of bipolar cells was 40% greater than that of multipolar cells (P〈0.02). Three cells (2.9%) had only one primary process. The DiI stain could be converted into a stable electron-opaque product. Electron-microscopic observations showed that these cells had the typical appearance of ICCs reported in previous studies. This staining method should be useful for physiological investigations of ICCs in gastrointestinal tissues.
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  • 18
    ISSN: 1432-0878
    Keywords: Key words Cutaneous scent glands ; Apocrine glands ; Myoepithelial cells ; Holocrine glands ; Ultrastructure ; Lectins ; Cytokeratins ; Impala ; Aepyceros melampus (Artiodactyla)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The cutaneous glands of the forehead and the metatarsus were studied by histological and histochemical methods and electron microscopy in adult male and female impalas in various seasons of the year. All glandular areas consist of apocrine and holocrine glands, which, however, occur in different proportions. Our findings in the apocrine gland cells suggest (1) the synthesis and exocytosis of a glycoproteinaceous secretory product stored in secretory granules, (2) typical apocrine secretion of the transformed apical cytoplasm, and (3) transepithelial fluid transport. The Golgi apparatus and apical membrane have binding sites for several lectins (PNA, HPA, RCA I, WGA). Cytokeratins 7, 14 and 19 are expressed at various intracellular localizations, suggesting an active role in the secretory mechanisms. The glands of the male forehead show marked seasonal changes in activity that are correlated with the main phases of the reproductive cycle, with the highest cellular activity occurring during the rut in April/May. The female forehead glands are only moderately developed and do not undergo seasonal changes. The metatarsal glands are of equal size in males and females and show no seasonal changes in activity. This study supports the hypothesis that (1) forehead glands in the male have a signaling role in the rut and (2) the metatarsal glands have a more general, probably social role maintaining and restoring contact between herd members.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 293 (1998), S. 165-171 
    ISSN: 1432-0878
    Keywords: Key words Muscle injury ; Cytoskeleton ; Sarcomere organisation ; Immunohistochemistry ; Ultrastructure ; Rabbit (New Zealand White)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immunohistochemical and electron-microscopic techniques were used to analyze the extensor digitorum longus muscles of New Zealand White rabbits 1 h, 1 day, 3, 7, and 28 days after repetitive eccentric contractions. Loss of the cytoskeletal protein desmin was the earliest manifestation of injury. Apart from 1 h post-exercise, all desmin-negative fibers stained positively with antibody to plasma fibronectin, indicating loss of cellular integrity accompanying cytoskeletal disruption. Fiber sizes were significantly increased from 1–7 days after exercise. The large (hyaline) fibers found in histological sections after repetitive eccentric contractions resulted from segmental hypercontraction of the fiber. This phenomenon occurred proximally and distally to plasma membrane lesions of the muscle fiber and necrosis and manifested itself as very short sarcomere lengths. Thus, in serial sections, staining characteristics, sizes and shapes of one and the same fiber often varied dramatically. We conclude that the following sequence of events occurs: cytoskeletal disruptions, loss of myofibrillar registry, i.e., Z-disk streaming and A-band disorganization, and loss of cell integrity as manifested by intracellular plasma fibronectin stain, hypercontracted regions, and invasion of cells. When a fiber is disrupted, the remaining intact fibers apparently take up the tension put on the muscle and later fewer fibers are subjected to eccentric contractions.
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  • 20
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    Cell & tissue research 294 (1998), S. 253-260 
    ISSN: 1432-0878
    Keywords: Key words P2X1 receptor ; Ultrastructure ; Cerebellum ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The distribution of the P2X1 subtype of purinoceptors associated with the extracellular activities of ATP was studied in the rat cerebellum at the electron-microscope level. Receptors were labelled with peroxidase-antiperoxidase and the avidin-biotin-peroxidase complex for immunocytochemistry. Immunoreactivity to P2X1 receptors was localized in subpopulations of synapses between varicosities of parallel fibres of granule cells and dendritic spines of Purkinje cells. Unlabelled varicosities of parallel fibres formed asymmetric synapses with labelled dendritic spines, whereas labelled varicosities of parallel fibres formed asymmetric synapses with unlabelled dendritic spines. P2X1 immunoreactivity was also localized in some astrocyte processes. The functional significance of these findings is discussed.
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  • 21
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    Cell & tissue research 294 (1998), S. 367-375 
    ISSN: 1432-0878
    Keywords: Key words Neurons ; Glia ; Tracheae ; Wing ; Ultrastructure ; Moth ; Manduca sp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  This ultrastructural examination of sensory nerves of the Manduca wing has revealed that extensive remodeling occurs among insect sensory neurons and their associated glial cells between pupation and adult emergence. Systematic counts of axons in particular wing nerves throughout adult development have shown that a decrease in axon number per nerve occurs after day 6. The neurons and glial cells that die are believed to be cells present at pupation that have no apparent sensory function but that probably function as guidance scaffolding for neurons and glia that are born after pupation. Despite the loss of several axons from each wing nerve, these nerves continue to grow in diameter during the latter half of adult development as some of the surviving axons increase severalfold in diameter. Each growing wing nerve in turn apparently functions as a scaffold for the proximal to distal growth of adult tracheae. A correspondence exists between adult nerve pathways and adult tracheal pathways, with each trachea maintaining intimate contact with a wing nerve along its entire length.
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  • 22
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    Cell & tissue research 291 (1998), S. 549-559 
    ISSN: 1432-0878
    Keywords: Key words Endolymphatic sac ; Ultrastructure ; Fluid transport ; Otoconia ; Newt ; Cynops pyrrhogaster (Urodela)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the “floccular” vesicle and the “granular” vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain flocccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.
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  • 23
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    Cell & tissue research 293 (1998), S. 253-269 
    ISSN: 1432-0878
    Keywords: Key words Septate junctions ; Ultrastructure ; Permeability ; Ions ; Epithelium ; Photoreceptor ; Hirudo medicinalis (Hirudinea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The leech photoreceptor forms a unicellular epithelium: every cell surrounds an extracellular “vacuole” that is connected to the remaining extracellular space via narrow clefts containing pleated septate junctions. We analyzed the complete structural layout of all septa within the junctional complex in elastic brightfield stereo electron micrographs of semithin serial sections from photoreceptors infiltrated with colloidal lanthanum. The septa form tortuous interseptal corridors that are spatially continuous, and open ended basally and apically. Individual septa seem to be impermeable to lanthanum; interseptal corridors form the only diffusional pathway for this ion. The junctions form no diffusion barrier for the electron-dense tracer Ba2+, but they hinder the diffusion of various hydrophilic fluorescent dyes as demonstrated by confocal laser scanning microscopy (CLSM) of live cells. Even those dyes that penetrate gap junctions do not diffuse beyond the septate junctions. The aqueous diffusion pathway within the septal corridors is, therefore, less permeable than the gap-junctional pore. Our morphological results combined with published electrophysiological data suggest that the septa themselves are not completely tight for small physiologically relevant ions. We also examined, by CLSM, whether the septate junctions create a permeability barrier for the lateral diffusion of fluorescent lipophilic dyes incorporated into the peripheral membrane domain. AFC16, claimed to remain in the outer membrane leaflet, does not diffuse beyond the junctional region, whereas DiIC16, claimed to flip-flop, does. Thus, pleated septate junctions, like vertebrate tight junctions, contribute to the maintenance of cell polarity.
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  • 24
    ISSN: 1432-0878
    Keywords: Key words Angiogenesis ; Capillary growth ; Prazosin ; Shear stress ; Skeletal muscle ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Chronic vasodilatation represents a stimulus for capillary growth associated with increased luminal shear stress. We have examined the ultrastructure of more than 2000 capillaries to establish whether the sequence of angiogenesis in response to this stimulus is similar to that described during development and under pathological circumstances. Administration of the α1-blocker prazosin to rats for 2 weeks led to a greater capillary length density in extensor hallucis proprius muscles without any change in capillary tortuosity: J v(c,f)=262±54 compared with 350±17 mm–2, control compared with prazosin (P〈0.002). There were obvious signs of endothelial cell (EC) activation after prazosin treatment, including an increased proportion of capillaries with rough endoplasmic reticulum, large cytoplasmic vacuoles, thickened endothelium and an irregular luminal surface. Capillaries from control muscles had a maximum of three ECs in cross section, whereas four ECs were noted in 0.8+0.5% of capillaries after 1 week (n.s.) and 2.5±0.9% after 2 weeks (P〈0.01) of treatment. This could be due to elongation and/or migration of ECs, as cell proliferation has not been described at these time points. There was also an increase in the proportion of capillaries having a narrow, slit-like lumen (1.7±0.8% of controls; 7.1±1.9% at 1 week; 8.8±2.5% at 2 weeks; P〈0.02), some of which were smaller in size (less than 2 μm diameter) than in controls (3–5 μm) and/or “seamless”, i.e. lacking EC junctions. These may represent newly formed vessels. Focal discontinuity of the basement membrane and abluminal EC processes were rarely seen, and capillary growth by abluminal sprouting appeared to be very infrequent (less than 0.001% of profiles). Of more importance was growth starting from the luminal side. Significantly more thin cytoplasmic processes were observed protruding into the lumen of capillaries after 1 week (47.5±6.2%, P〈0.001) and 2 weeks of prazosin (34.2±5.5%, P〈0.05) than in control vessels (16.7±3.9%). Some of these traversed the entire lumen and connected with endothelium of the opposite side, probably involving membrane fusion, resulting in the appearance of a double lumen. Individual capillaries with a complete double lumen were observed after 2 weeks’ prazosin but comparatively rarely, in only four out of six muscles. These findings indicate a pattern of luminal growth which is completely different from intussusceptive growth previously described during development, and from the abluminal capillary sprouting seen under pathological circumstances.
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  • 25
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    Protoplasma 204 (1998), S. 155-169 
    ISSN: 1615-6102
    Keywords: Spores ; Ultrastructure ; Entorrhiza ; Microbotryum ; Tilletia ; Ustilago
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The concept and nomenclature for the elements of teliospore walls in smut fungi are presented and a survey of teliosporogenesis is given, as seen by light and transmission electron microscopy. Four developmental types are distinguished: the Ustilago, Microbotryum, Tilletia, and Entorrhiza type. In the Ustilago type, sporogenous hyphae are completely segmented into teliospore initials which are embedded in a hyaline matrix formed by gelatinised hyphal walls (found in species ofAnthracoidea, Cintractia, Heterotolyposporium, Kuntzeomyces, Macalpinomyces, Melanopsichium, Sporisorium, Testicularia, Tolyposporium junci, Trichocintractia, and species ofUstilago infecting members of the family Poaceae). In the Microbotryum type, septate sporogenous hyphae are also completely segmented into teliospore initials, however, they are not surrounded by a hyaline matrix (Microbotryum, Sphacelotheca, Ustilago spp. infecting dicotyledons). A yeast-like budding of teliosporogenic cells is observed for some species ofMicrobotryum, Sphacelotheca, andUstilago infecting dicotyledons. In the Tilletia type, teliospores differentiate locally in the sporogenous hyphae, in an apical or intercalary position, without a hyaline matrix (Conidiosporomyces, Doassinga, Entyloma, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, Rhamphospora, Tilletia). In all these types, the teliospore initials first develop a hyaline sheath under which the ornamentation, the exosporium, sometimes a middle layer, and the endosporium are successively deposited by the fungal cell. In the Entorrhiza type, the teliospores develop inside vital host cells with the wall of the sporogenous hypha included into the teliospore wall. The fungus develops a middle layer and an electron-transparent endosporium inside the hyphal wall while a layer forming the ornamentation is deposited onto the hyphal wall, probably by vesicles of dictyosomes of the host cell.
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  • 26
    ISSN: 1615-6102
    Keywords: Neck cell proliferation ; Binucleate ; Douglas fir ; Conifers ; Genetic instability ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To study the effect of culturing on megagametophytes of Douglas fir (Pseudotsuga menziesii) and hybrid larch (Larix × eurolepis), cones were collected at the time of fertilization and the megagametophytes were removed, then placed on medium. We used a modified Murashige and Skoog medium supplemented with 5% lactose and 10% polyethylene glycol 4000. A variety of cell types proliferated including prothallial, neck, and jacket cells. Some of these multiplying cells showed a binucleate condition. The prothallial cells of the apex divided and expanded. The neck cells formed clusters composed of more cells than normally found in situ; though otherwise they showed ultrastructural similarity to neck cells in situ. These neck cells had large numbers of active Golgi complexes, numerous large and small vacuoles, coated vesicles, smooth vesicles, a well-developed endoplasmic reticulum, and thickened cell walls. These are the first reports of neck cell multiplication and induction of a binucleate state for gymnosperm megagametophyte cells in vitro.
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  • 27
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    Protoplasma 201 (1998), S. 30-37 
    ISSN: 1615-6102
    Keywords: Cell-to-cell communication ; Plasmodesmata ; Ultrastructure ; Wounding ; 2-Deoxy-D-glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transport of ions and metabolites through plasmodesmata has been thought to be controlled at the neck region where the cytoplasmic annulus is constricted and where callose has also been localised. In order to determine the possible structural and functional effects of callose, its deposition was inhibited through incubation of the plant tissue with 2-deoxy-D-glucose (DDG) for 1 h prior to fixation in 2.5% glutaraldehyde. The inhibition of callose formation was monitored through aniline blue-induced fluorescence of callose. The neck region of the plasmodesmata fromAllium cepa L. roots treated with DDG exhibited a funnel-shaped configuration. This is in contrast to the plasmodesmata from tissue not incubated with DDG, which exhibited constricted necks similar to those previously reported. Both initial dissection and glutaraldehyde fixation induced neck constriction in plasmodesmata, however, dissection of tissue increased the frequency of constrictions. The inhibition of callose formation by chemical means showed that the neck constrictions and raised collars in this area are artefacts due to physical wounding and glutaraldehyde fixation. The external electron-dense material observed when tannic acid is included in the primary fixative appears to be unrelated to the deposition of callose at the neck region.
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  • 28
    ISSN: 1615-6102
    Keywords: Chloroplast development ; Cotton ; Fluorescence induction kinetics ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many of the studies of chloroplast ontogeny in higher plants have utilized suboptimal conditions of light and growth to assess development. In this study, we utilized structural, immunological, and physiological techniques to examine the development of the chloroplast in fieldgrown cotton (Gossypium hirsutum cv. “MD 51 ne”). Our youngest leaf sample developmentally was completely folded upon itself and about 0.5 cm in length; leaves of this same plastochron were followed for three weeks to the fully expanded leaf. The chloroplasts at the earliest stage monitored had almost all of the lamellae in small, relatively electron-opaque grana, with relatively few thylakoids which were not appressed on at least one surface. During the development of the thylakoids, the membranes increase in complexity, with considerable stroma lamellae development and an increase in the number of thylakoids per granum. Besides the increase in complexity, both the size and numbers of the chloroplast increase during the development of the leaf. Developmental changes in six thylakoid proteins, five stromal proteins, and one peroxisomal protein were monitored by quantitative immunocytochemistry. Even at the earliest stages of development, the plastids are equipped with the proteins required to carry out both light and dark reactions of photosynthesis. Several of the proteins follow three phases of accumulation: a relatively high density at early stages, a linear increase to keep step with chloroplast growth, and a final accumulation in the mature chloroplast. Photosystem-II(PS II)-related proteins are present at their highest densities early in development, with an accumulation of other parts of the photosynthetic apparatus at a latter stage. The early accumulation of PS-II-related proteins correlates with the much lower ratio of chlorophylla tob in the younger leaves and with the changes in fluorescence transients. These data indicate that some of the conclusions on chloroplast development based upon studies of intercalary meristems of monocots or the greening of etiolated plants may not be adequate to explain development of chloroplasts in leaves from apical meristems grown under natural conditions.
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  • 29
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    Protoplasma 201 (1998), S. 101-109 
    ISSN: 1615-6102
    Keywords: Kinetochore ; Kinetoplastida ; Intranuclear microtubules ; Mitosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The three-dimensional ultrastructural organization of the mitotic apparatus ofDimastigella mimosa was studied by computer-aided, serial-section reconstruction. The nuclear envelope remains intact during nuclear division. During mitosis, chromosomes do not condense, whereas intranuclear microtubules are found in close association with six pairs of kinetochores. No discrete microtubule-organizing centers, except kinetochore pairs, could be found within the nucleus. The intranuclear microtubules form six separate bundles oriented at different angles to each other. Each bundle contains up to 8 tightly packed microtubules which push the daughter kinetochores apart. At late anaphase only, midzones of these bundles align along an extended interzonal spindle within the narrow isthmus between segregating progeny nuclei. The nuclear division inD. mimosa can be described as closed intranuclear mitosis with acentric and separate microtubular bundles and weakly condensed chromosomes.
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  • 30
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    Plant systematics and evolution 210 (1998), S. 25-39 
    ISSN: 1615-6110
    Keywords: Cyanophyta ; Cyanobacteria ; Cyanothece ; Synechococcus ; Cyanobium ; Ultrastructure ; nucleoids ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fine structure of the type species of the genusCyanothece Komárek 1976,C. aeruginosa, is described and compared with the main cytological characteristics of morphologically related members of the generaCyanobium, Cyanobacterium andSynechococcus. Several morphological features, such as cell walls with thick outer layers containing a special type of vesicles, position of thylakoids, “keritomy” (net-like appearance of protoplast caused by arrangement of thylakoids, net-like nucleoids and/or by tendency to form intrathylakoidal spaces) and a special structure of mucilaginous envelopes were found to be characteristic of this genus, supporting its separate position among coccal cyanoprokaryotes (cyanobacteria, cyanophytes). The taxonomic significance of ultrastructural features in all mentioned genera is discussed.
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  • 31
    ISSN: 1615-6102
    Keywords: Spore balls ; Germ areas ; Ultrastructure ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Special features of teliospores in smut fungi are described, including teliospore connections, appendages, and germ pores. Balls of teliospores in species of many different genera cohere by remnants of hyphal walls, sheaths, and sometimes interlocking ornamentation. Teliospores are connected in pairs in species ofMycosyrinx andGeminago by special local structures. Appendages can be formed locally by persistent material from the sheath (Cintractia, Anthracoidea, Sphacelotheca), thickened parts of the spore wall (e.g.,Georgefischeria, Jamesdicksonia, Rhamphospora, Tolyposporella), or persistent walls of sporogenous hyphae (Rhamphospora, genera of the Tilletia relationship). Species ofGeorgefischeria, Jamesdicksonia, andTolyposporella have teliospore walls composed of more than three layers of different electron density. “Germ areas” corresponding to thinner parts of the spore wall are known, e.g., for species ofAnthracoidea, Cintractia, andUstilago infecting members of the family Poaceae, while distinct germ pores, one per teliospore, are found in some species ofThecaphora, “Tolyposporium”, andSporisorium. Teliospores ofMycosyrinx cissi have a germination ring. Characteristics of teliospores are used to discuss the phylogeny of smut fungi. A phylogenetic tree in accordance with teliospore characteristics is compared to those obtained from ultrastructural characteristics of host-parasite interaction, of septal pores, and from sequence data. Aspects of teliospore development help to define taxa at a high systematic level (Entorrhizales, Ustilaginales, Tilletiales/Entylomatales, Microbotryaceae), while details of ornamentation ontogeny delimit groups of genera (e.g., genera related toUstilago on members of the Poaceae andSporisorium, Cintractia andAnthracoidea, Tilletia) or single genera (e.g.,Melanopsichium, Dermatosorus, Mycosyrinx, Doassinga, Rhamphospora). Types of ornamentation (warty, reticulate), middle layers, teliospore balls, and germ pores evolved repeatedly by convergence. The smut teliospore itself probably evolved independently at least twice, or perhaps three (or more) times, in the Microbotryales, in the Entorrhizales, and in a common ancestor of the remainder of the Ustilaginomycetes.
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  • 32
    ISSN: 1615-6102
    Keywords: Spores ; Ultrastructure ; Microbotryum ; Tilletia ; Tolyposporium ; Ustilago
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The walls of mature teliospores and the development of ornamentation, as seen by transmission electron microscopy, are described for 37 genera of smut fungi, based on observations of ca. 120 species and on literature. Structural diversity of mature teliospore walls is due to differences in spore wall layers forming the spore wall (endosporium, middle layer, exosporium, ornamentation) and to different elements forming the ornamentation (exosporium, ornaments, sheath, hyphal wall, adjacent fungal cells, material of the host). During teliosporogenesis the outer layers are usually deposited first. At the beginning of the formation of the ornamentation the plasma membrane may be smooth or undulated carrying the developing ornaments on its tips or in its depressions. The ornamentation of some genera appears similar when seen by scanning electron microscopy, but can be the product of different developmental patterns (e.g., warts of species ofFarysia, Tilletia, andUstilago), however, warty and reticulate ornamentation can both be produced by similar developmental processes (shown, e.g., for species ofCintractia andTilletia). Typical structures of the mature teliospore wall and developmental patterns based on homologous similarities are described for the following groups of genera or species:Macalpinomyces, Melanopsichium, Sporisorium, andUstilago infecting members of the family Poaceae;Kuntzeomyces, Testicularia, andTrichocintractia; Anthracoidea, Cintractia, Heterotolyposporium piluliforme, andTolyposporium junci; Glomosporium, Sorosporium, andThecaphora; Conidiosporomyces, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, andTilletia; Entyloma, and genera of the Doassansia group;Liroa, Microbotryum, Sphacelotheca, Ustilago infecting dicotyledons, andZundeliomyces; Aurantiosporium, Fulvisporium, andUstilentyloma. Special characteristics of the teliospore wall were observed for the generaDermatosorus, Doassinga, Entorrhha, Farysia, Mycosyrinx, Rhamphospora, and some species ofTolyposporium.
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  • 33
    ISSN: 1860-1499
    Keywords: Solitary fibrous tumor of the pleura ; Mesenchymal cell ; Immunohistochemistry ; CD 34 ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A solitary fibrous tumor of the pleura (SFTP) in a 37-year-old woman was reported as a rare pleural tumor based on morphological, immunohistochemical, and electron microscopic studies. The results showed that the tumor was composed of spindle-shaped cells forming fascicular and interlacing patterns with a mixture of mature collagen. The tumor cells coexpressed vimentin and CD34 and lacked cytokeratin reactivity. Ultrastructurally, there were abundant collagenous fibrillae surrounding spindle-shaped cells in which the junctional complex, basement membrane-like structure, and microvilli were not seen. From literature review and observation of the morphological features around the tumor, we consider that the tumor originated from the stromal cells subjacent to the mesothelium.
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  • 34
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    Medical molecular morphology 31 (1998), S. 151-155 
    ISSN: 1860-1499
    Keywords: Serous adenocarcinoma ; Peritoneal neoplasm ; Immunohistochemistry ; Ultrastructure ; Case report
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two cases of serous surface carcinoma of the peritoneum (SSCP) are discussed. The first patient was a 48-year-old Japanese woman with abdominal pain and fullness. The second patient was a 66-year-old Japanese woman with abdominal fullness. In both patients, laparotomy revealed many tumor nodules on the peritoneal surface. However, the ovaries, the uterus, and other intraperitoneal organs were free from tumors. The serum levels of CA125 were excessively elevated. The tumor cells were arranged in a papillotubular pattern. Mitoses were frequent. Diastaseresistant PAS-positive, and hyaluronidase-resistant alcian blue-positive materials were observed. In immunohistochemistry, the tumor cells showed positive reactions for cytokeratin, EMA, CA125, and HBME-1, and, in contrast, negative reactions for CEA, thrombomodulin, vimentin, and HHF35. In analysis for Ber-EP4, all tumor cells of case 1 were negative, and a few tumor cells of case 2 were positive. Ultrastructurally, hobnail-shaped tumor cells rested on a continuous basal lamina. Each cell was attached to short desmosomes. Microvilli were slender, straight, and short, and some had core rootlets. Many primary lysosomes were aggregated in the basal portion of the cytoplasm. A few well-differentiated ciliated cells were present. These two cases were diagnosed as SSCP.
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  • 35
    ISSN: 1860-1499
    Keywords: Restitution ; Ultrastructure ; Cell migration ; Colon ; Saponin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The superficial colonic epithelia of rats were exposed to 1.0% saponin solution for 3 min and fixed at various periods thereafter. The repair or restitution process was observed by light as well as by transmission and scanning electron microscopy. The exposure of the luminal surface to saponin resulted in uniform and extensive damage to the superficial epithelial cells without affecting the cells in the crypts. At 3 min after saponin treatment, the damaged epithelial cells exfoliated from the mucosa and the basal lamina was exposed. Within 15 min, most of the exposed basal lamina was covered by squamous to low-cuboidal epithelial cells, probably migrating from the crypts. These epithelial cells extended large lamellipodia over the denuded basal lamina. After 15 min the damaged surface was completely covered with epithelial cells, which became columnar at 1 h. Tight junction protein ZO-1 became positive along the restituted epithelium. Proliferating-cell nuclear antigen (PCNA) staining showed that proliferation of epithelial cells occurred after the restitution. These results suggest that saponin treatment serves as a good model system to study colonic restitution, which is carried out by rapid migration from the remaining crypt cells, followed by cellular proliferation. Rapid formation of tight junctions spanning the damaged regions allows rapid restoration of the barrier function of the colonic epithelium.
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  • 36
    ISSN: 1860-1499
    Keywords: Pancreas ; Peripheral nerve ; Cancer ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nerve invasion is one of the biological features of pancreatic cancer, and its mechanism remains to be determined. In this paper, we report on 37 pancreatic cancer specimens observed by immunohistochemical and electron microscopical techniques. The results showed that pancreatic cancer directly invaded and destroyed the perineurium. At the early stage of disease, the peripheral nerve and synaptic membrane were easily destroyed by cancer cells, and invasion and metastasis continuously advanced along the perineural space and central side of nerves. These results suggest that the soft tissue and nerve plexus on the dorsal region of the pancreas may contribute to the recurrence of pancreatic cancer after duodenopancreatectomy.
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  • 37
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    Medical molecular morphology 31 (1998), S. 185-192 
    ISSN: 1860-1499
    Keywords: Rat fetal heart ; Capillary angiogenesis M ; Myocardial cleft ; Fibroblast ; Desmosome-like structure ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To determine the course of capillary angiogenesis in the rat fetal heart, transmission electron microscopy was used to examine the development of both capillaries and cardiomyocytes. In the 15-day-old embryo, the coronary vessels had spread into the superficial space. In the 16-day-old embryo, the coronary vessels began to enter the myocardium. In the 17-day-old embryo, the terminal vascular bed had developed and a marked increase in the population of myocytes was evident. In capillaries entering the myocardium, the outgrowth of endothelial cells into the myocardial cleft was evident. These clefts were formed by intercalated disk and desmosome-like structures. The fibroblasts were always found close to the capillaries or in contact with endothelial cells during the fetal stage to the first neonatal week. In the interstition period, the fibroblasts were not found close to the capillaries. These results are discussed in relation to the role of myocardial clefts and the role of fibroblasts in fetal capillary angiogenesis.
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  • 38
    ISSN: 1860-1499
    Keywords: Malignant myoepithelioma ; Oral palate ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Malignant myoepithelioma arising in the palatal gland is extremely rare. The present study demonstrated ultrastructural and immunohistochemical features of malignant myoepithelioma transformed from long-standing benign myoepithelioma occurring in the palatal gland. Microscopically, the tumor mass was composed of plasmacytoid cells and epitheloid cells. The malignant feature was seen only at the area adjacent to the bone. Immunohistochemically, most of the cells were S-100 positive, whereas vimentin and keratin were only partially positive. Glial fibrillary acid protein (GFAP) was positive at the peripheral cells of the solid nests and epitheloid cells with myxoid stroma. Ultrastructurally, filament-rich cells, tonofilament-rich cells, and filament-poor cells were observed. At the area adjacent to the bone, the cells implying malignancy were filament-poor cells in which the luminal structures could be detected. From these findings, a scarcity of filaments in myoepitheliomatous components may imply a malignancy.
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  • 39
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    European archives of oto-rhino-laryngology and head & neck 243 (1986), S. 121-125 
    ISSN: 1434-4726
    Keywords: Bacterial labyrinthitis ; Ultrastructure ; Mycobacterium ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We used electron microscopy to investigate Mycobacterium fortuitum -induced changes in the inner ears of mice. We found that the inner and outer hair cells had degenerated and disappeared in the organ of Corti. Changes in the lower turn of the cochlea were more severe than those of the upper turn while the changes of the outer hair cells were more severe than those of the inner hair cells. Disappearance, fusion and ballooning of the sensory hairs were observed in the vestibular organs. The bacterial extract also induced inner ear damage which was similar to that caused by live M. fortuitum.
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  • 40
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    European archives of oto-rhino-laryngology and head & neck 243 (1986), S. 260-264 
    ISSN: 1434-4726
    Keywords: Argyria ; Chemosensory function ; Oral Mucosa ; Ultrastructure ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Generalized argyrosis can produce a number of abnormalities, including skin discoloration, liver and kidney dysfunction. We describe a patient with generalized argyrosis following long-term self-treatment with oral silver intake, in whom skin discoloration, progressive taste and smell disorders, vertigo and hypesthesia were observed. These findings were confirmed by chemosensory tests and electrophysiological investigations. The development of hypogeusia was assessed by subjective tests, while the progression of hyposmia was followed by recording olfactory evoked cortical potentials. Light and electron microscopy of tissue samplings demonstrated electron-dense mineral deposits in basal membranes, in macrophages, in the perineurium of peripheral nerves, along elastic and collagenous fibers, and in necrotic cells of the oral submucosa. Silver and sulfur deposits in affected tissues could be defined by X-ray microanalysis. The quantitative ratio between silver and sulfur in involved tissues was similar to that of an inorganic silver-sulfide (Ag2S) standard. The minute increase in the sulfur content when compared to the inorganic standard suggested a sulfur containing organic matrix of the tissue precipitates. Our findings indicate that the affinity of silver for membrane and neuronal structures and the deposition of silver as an insoluble compound (Ag2S) induce the progression of clinical disease.
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  • 41
    ISSN: 1432-0584
    Keywords: Karyotype ; Bladder carcinoma ; Ultrastructure ; CSF ; Cell line
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cell line 5637 which originated from a human urinary bladder carcinoma is known to produce GM-CSF and Multi-CSF ectopically. Determination of cell surface antigens defined by monoclonal antibodies was recently reported [6]. Here we report on the ultrastructure and karyology of this CSF secreting cell line. At the ultrastructural level the monolayer in vitro culture and the solid tumors formed in nude mice showed all characteristics consistent with a well-differentiated transitional cell carcinoma (TCC). A subclone was found to grow in suspension and did not secrete any CSF activity. High resolution chromsome analysis revealed chromosomal abnormalities which agreed only in few particulars with nonrandom chromosomal aberrations usually found in TCC. Analysis of the cytogenetic results showed that nearly all structural abnormalities present are known to be associated with acute or chronic human leukemia. The possibility that the ectopic production of CSF in this cell line may be correlated to one or more of the described chromosomal aberrations is discussed.
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  • 42
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    Archives of dermatological research 278 (1986), S. 398-406 
    ISSN: 1432-069X
    Keywords: Nevocytic nevi ; Congenital ; Ultrastructure ; Nevus cells ; Nerve contacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary As only few previous investigations considered size-dependent differences in the histology of congenital nevocytic nevi (CNN) or focused on their ultrastructure, a light- and electron-microscopic study of six giant and six medium-sized CNN was performed. Histologically, giant CNN showed minimal junctional nevus elements and a pandermal, diffuse nevus cell extension including the subcutaneous tissue, while medium-sized CNN exhibited more abundant junctional nests and a rather focal pattern of nevus cell extension into the reticular dermis. Ultrastructurally, giant CNN often showed nevus cells with irregular and indented nuclei and also nevus cells with highly complicated dendrites. Nuclear inclusions, multiple cilia and centrioles, and collagen phagocytosis in nevus cells were found in both groups of CNN. Direct contacts between nevus cells and nerve fibers were observed in mediumsized CNN only. The findings provided no clear morphological indication why giant CNN have a higher risk for malignant degeneration than medium-sized CNN or acquired nevocytic nevi (ANN). On the other hand, the histological differences speak in favor of a different ontogenesis of the various size classes of CNN and ANN.
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  • 43
    ISSN: 1432-2307
    Keywords: Epithelioid haemangioendothelioma ; IVBAT ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three patients with epithelioid haemangioendothelioma (EHE) are described. Two patients presented with pulmonary infiltrates and one with a hepatic tumour. All had a metastatic disease ending fatally, and all were autopsied. The diagnosis was confirmed either by immunohistological or ultrastructural analysis. All three tumours were cytokeratin-negative and vimentin-positive, while only two contained cells reacting with the antibody of factor VIII-related antigen. Electron microscopy of the third tumour revealed features indicating endothelial differentation. A short literature review is also presented demonstrating that the outlook of EHE is worse than previously thought.
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  • 44
    ISSN: 1432-2307
    Keywords: Mesothelioma ; Serous membrane ; Localized tumour ; Histogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It is uncertain whether localized lesions of serosal membranes have a kinship to mesotheliomas or are truly fibromatous in nature. Ultrastructural and immunohistochemical investigations were carried out on 12 localized benign and malignant pleural and peritoneal tumours from 10 patients. Electron microscopic findings, including the consistent and non-fibroblastic cellular organization of localized neoplasms, the presence of some form of intercellular junctions in 7 of 10 cases, basal lamina deposition in 3 cases, and polarized microvilli in one case indicated a form of mesothelial differentiation. Using monoclonal and polyclonal antibodies, positive immunostaining of tumour cells for cytokeratin peptides was detected in one case, while antibody to vimentin stained four cases. Light microscopic, ultrastructural and immunohistochemical features of one benign localized serosal tumour, with a unique blend of epithelial and spindle cells, provided further evidence for a histogenic link between localized serosal tumours and diffuse epithelial mesotheliomas. On the basis of the current findings and reports in the literature, it would appear that the majority of localized tumours of serosal membranes are a subset of mesothelioma, while a minority are fibromas.
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  • 45
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    Virchows Archiv 410 (1986), S. 43-48 
    ISSN: 1432-2307
    Keywords: Endocarditis ; Staphylococcus ; Colonisation ; Morphology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The initial colonization, byStaphylococcus aureus, of the catheter damaged aortic valve and aorta of the rabbit, was examined by light and electron microscopy at 15 min, 3 h and 24 h post inoculation (PI). At 15 min PI, the majority of bacteria (80%) were located on the lateral surfaces of the thrombic vegetations while 20% were attached directly to the connective tissue of the aortic valve and aorta in areas where the endothelial lining was disrupted. By 3 h the bacteria on the thrombic vegetations were covered by fibrin. At this time, the bacteria both within the vegetations and on the surface of the vasculature were undergoing multiplication to form small groups. The precipitation of thrombus around the bacteria attached to the surface of the aorta to form microscopic infected vegetations had occurred by 24 h PI. The colonizing bacteria did not elicit any phagocytic response. The colonization of the cardiovasculature byStaph. aureus did not necessarily require pre-existing vegetations.
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  • 46
    ISSN: 1432-2307
    Keywords: Human acute pancreatitis ; Enzyme immunocytochemistry ; Ultrastructure ; Acinar cell degranulation ; Fat necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human acute pancreatitis results from an autodigestive process frequently associated with alcohol abuse, gall stone disease and shock. Peripancreatic fat necrosis was identified as one of the earliest visible lesions, whereas acinar cell necrosis and haemorrhage were regarded as secondary changes. To examine the alterations in acinar cells in more detail, their enzyme content and fine structural features were studied immunocytochemically using antisera against α-amylase, lipase, trypsin, chymotrypsin and pancreatic stone protein, and electronmicroscopically in pancreatic tissues from patients with severe acute pancreatitis. Peripheral acinar cells in the immediate vicinity of fat necrosis were found to be heavily degranulated, while acinar cells at some distance of necrosis fully retained their enzyme content. Other frequent changes of the acinar cells included cuboidal transformation, loss of microvilli, increased occurrence of autophagosomes, and formation of enlarged acinar lumina. As there was no apparent cell membrane leakage or rupture of duct lumina, it is concluded that the acinar cells adjacent to fat necrosis release their granules by undirected basolateral extrusion. The findings thus suggest that one of the basic defects in acute pancreatitis is the uncontrolled release of enzymes from peripheral acinar cells into the interstitial space which, in turn, presumably by the action of lipase, leads to autodigestive fat necrosis.
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  • 47
    ISSN: 1434-0879
    Keywords: Monkey spermatozoa ; Gossypol effect ; In vivo examination ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study examines the ultrastructure of ejaculated spermatoza from bonnet monkey, Macaca radiata under noraml conditions, with gossypol treatment and during recovery from such treatment. Monkeys were fed orally with gossypol acetic acid (GAA) for 3 months (4 mg/monkey/5 days a weak). Semen samples collected by electroejaculation, and the spermatozoa were examined using both light and electron microscopy. The degree of motility was also noted by Kalla et al. [12]. Ejaculated spermatoza were immotile 90 days after GAA treatment, but little evidence for any abnormality in the spermatozoa could be seen by light microscopy. Some ultrastructural changes were observed, but not to the extent previously reported in spermatozoa of Macaca fascicularis [23]. After termination of treatment, semen samples were obtained every 5th day until sperm count and motility recovered to the normal level. After 90 days only a small proportion of spermatozoa showed abnormal structure. We conclude that in a subhuman animal model gossypol induced effects on sperm motility and morphology are reversible.
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  • 48
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    Anatomy and embryology 173 (1986), S. 295-298 
    ISSN: 1432-0568
    Keywords: Cardiodilatin ; Peptide Hormone ; Heart ; Human ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The immunogold technique was applied to detect cardiodilatin-immunoreactivity (CDD-IR) in human heart. Using antibodies directed against C-terminal regions of CDD, we could identify colloidal gold label in specific atrial granules of human heart. The granules in all areas of the myoendocrine cells were homogeneously labelled and all right atrial biopsy specimen of patients with different heart diseases reacted positively and had the same distribution of label. The Golgi-apparatus and ergastoplasma exhibited and extremely weak CDD-IR. The results indicate a predominant storage of CDD in specific granules.
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  • 49
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    Anatomy and embryology 173 (1986), S. 361-370 
    ISSN: 1432-0568
    Keywords: Electrical synapses ; Chemical synapses ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thin sectioning and freeze-fracturing have revealed the distribution of gap junctions and chemical synapses in the synaptic interface of the large myelinated club endings on the lateral dendrite of the goldfish Mauthner cell. In 12 samples of club endings fractured completely or nearly completely, the apposed synaptic membrane area averaged 39.090 μm2, of which 16.6% was occupied by gap junctions and about 4 to 5% by the active zones of chemical synapses. The numerical profile density (number per unit area of the synaptic membrane) of gap junctions varied greatly, from 1.78 to 6.30, and was mostly in inverse proportion to their size. The chemical synapses were located mainly in two places: in the circumferential rim of the synaptic membrane next to the widened extracellular space, and in the margins of intraterminal invaginations of the synaptic cleft. The axoplasm of the preterminal axon, just after losing its myelin sheath, was filled with microtubules, among which neurofilaments gathered into many small bundles. The correlation between the areas of gap junctions and the chemical synapses and the amplitude of the excitatory postsynaptic potentials (EPSP) is discussed.
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  • 50
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    Anatomy and embryology 173 (1986), S. 385-391 
    ISSN: 1432-0568
    Keywords: Elastic cartilage ; Chondrogenesis ; External ear ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Selected ultrastructural features of chondrocytes and the extracellular matrix in the developing elastic cartilage of the external ear were studied in rat fetuses and young animals. The cytoplasmic lipid droplets were first observed in the 19-day fetus. They increase in number and size during the first post-natal week. The elastogenesis proceeds in the sequence: oxytalan fibers (17-day fetus), elaunin fibers (1-day rat), elastic fibers (5-day rat). Intermediary stages between the randomly oriented individual microfibrils and bundles of microfibrils (oxytalan fibers) were also observed.
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  • 51
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    Anatomy and embryology 174 (1986), S. 27-33 
    ISSN: 1432-0568
    Keywords: Cerebral cortex ; Antisera ; Biopsy ; Postmortem Alzheimer's type dementia ; Ultrastructure ; Epilepsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary NPY-containing neuronal structures in the cereoral cortex of surgical tissue samples were compared to those in postmortem material by immunocytochemical methods. However, the quality of preservation of individual neurons and axonal and dendritic plexuses in the neuropil is unusually fine in the surgical specimens. This result is most likely attributable to the excellent fixation that can be regularly achieved by rapid and careful handling of tissue during and after surgical removal. The tissue is suitable for both light and electron microscopy, and the superior preservation also leads to intense, reliable antibody reactions. Postmortem tissue samples can provide good specimens for immunocytochemistry when properly handled as previously described. However the postmortem delays prior to fixation disrupt neuronal integrity in the immunostained structures. Nevertheless, postmortem material from carefully studied subjects of neurological diseases compared with age matched controls can provide valuable information.
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  • 52
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    Anatomy and embryology 173 (1986), S. 317-322 
    ISSN: 1432-0568
    Keywords: Paneth cell ; Ultrastructure ; Morphometry ; Germfree rats ; Ex-germfree rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural changes of Paneth cells of germfree (Gf) rats which had been inoculated with bacteria-containing feces from conventionally-reared (SPF) rats were quantitatively examined. 12 and 24 h after inoculation, the Paneth cells showed a striking decrease in the number of secretory granules and the occurrence of large vacuoles. Phagosomes containing bacteria were not seen. After 4 days, the secretory granules reaccumulated and smooth-surfaced apical vesicles increased in number. It is discussed that the large vacuoles may be related to membrane-retrieval events following the massive extrusion of secretory granules whereas the apical vesicles appear to serve this function when exocytosis is not pronounced. In addition to the large secretory granules ca. 10% of Paneth cell profiles contained a few dense-cored vesicles measuring about 150 nm in diameter which resemble peptidergic neurosecretory granules.
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  • 53
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    Acta neuropathologica 71 (1986), S. 83-87 
    ISSN: 1432-0533
    Keywords: Astrocytes ; Brain neoplasms ; Oligodendroglioma ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural concentric laminations have previously been thought to be specific to oligodendroglioma. However, these structures were also recognized in fibrillary astrocytomas, a mixed glioma and a glioblastoma. These laminations continued or closely related to attenuated processes or cytoplasm of astrocytic tumor cells. In addition, some lamellae contained glial filaments. It is considered that the concentric laminations are derived from attenuated astrocytic processes and have no relationship with myelin.
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  • 54
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    Acta neuropathologica 70 (1986), S. 44-52 
    ISSN: 1432-0533
    Keywords: Gliosarcoma ; Myxoid tumor ; Extracranial metastasis ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The case of a 22-year-old female suffering from glioblastoma with sarcomatous component (WHO; gliosarcoma) is presented. The tumor consisted of glioblastomatous and sarcomatouos components, and in part of the pleomorphic astrocytomatous region of the glioblastoma there was a prominent production of myxoid matrix. On the basis of its histochemical and immunohistochemical characteristics, the present case strongly suggested that glial cells of neuroectodermal origin assume part of the responsibility for production of myxoid material.
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  • 55
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    Acta neuropathologica 72 (1986), S. 134-141 
    ISSN: 1432-0533
    Keywords: Cerebral embolism ; Fungal vasculitis ; Paecilomyces javanicus ; Prosthetic valve endocarditis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 41-year-old diabetic woman developed Paecilomyces javanicus endocarditis and subsequent cerebral fungal embolism and vasculitis with massive infarction and hemorrhage 6 years after a mitral valve replacement with porcine heterograft. The organism was identified by the culture from the infected brain tissue and aortic valve. Cerebral infection due to fungus Paecilomyces is rare. This report documents the cerebral manifestations of fungus Paecilomyces javanicus and describes for the first time the ultrastructure of such an organism obtained from the infected tissue. Their ultrastructural findings, similar to those described in Paecilomyces farinosus derived from culture, include a double-layered cell wall, a triple unit plasma membrane, abundant cytoplasmic lipid droplets, vacuoles, membranous profiles and septal formation. This report further demonstrates hyphae with packed 50A filaments and granulofibrillary material and features suggestive of intrahyphal hyphae, not previously described in fungus Paecilomyces.
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  • 56
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    Acta neuropathologica 70 (1986), S. 127-134 
    ISSN: 1432-0533
    Keywords: Avian muscle spindle ; Denervation ; Intrafusal fiber ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of the nerve in maintaining the ultrastructural integrity of avian muscle spindles was investigated by denervating the pigcon's extensor digitorum communis for periods of 10, 19, and 28 days. The equatorial region of control intrafusal fibers had a reduced density of myofilaments. Sensory endings contained mitochondria and structures resembling synaptic vesicles, and were associated with satellite cells. In the polar region, fibers had a high concentration of myofilaments; small motor endings, unlike sensory endings, lay outside of the fiber's basal lamina. The outer capsule consisted of thin, tightly layered cells which gradually became reduced in number distal to the equatorial region. In both equatorial and polar regions the capsule became more disrupted with longer denervation periods, and lysosomes and phagocytes became more abundant. The equatorial region of denervated fibers contained many myofibrils and some had peripherally-located nuclei, unlike the controls; sensory terminals were absent. The polar region of some fibers had disorganized myofilaments and others had a reduced myofilament density. Fiber diameters increased significantly in both regions. Thus, denervated intrafusal fibers lost some characteristics which distinguish them from extrafusal fibers.
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  • 57
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    Acta neuropathologica 70 (1986), S. 71-74 
    ISSN: 1432-0533
    Keywords: 6-Aminonicotinamide ; Ependymal cell ; Mitosis ; Suckling mice ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mitotic ependymal cells were encountered in 10-day-old mice treated with 6-aminonicotinamide, an antagonist of niacin. These occurred along the medial surface of the lateral ventricle and the ventral portion of the aqueduct. Electron microscopy revealed that both mitotic ependymal cells had eccentrically placed chromosomes without a nuclear membrane and well-formed gap junctions in contact with adjacent ependymal cells. Microtubules from a centriole radiated to the chromosomes. These data show that cell division occurs in morphologically matured ependymal cells in the postnatal brain under pathological conditions. We believe this to be the first ultrastructural demonstration of this phenomenon.
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  • 58
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    Anatomy and embryology 174 (1986), S. 379-389 
    ISSN: 1432-0568
    Keywords: Lungs ; Amphibia ; Ultrastructure ; Morphometry ; Surfactant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lungs ofHyla arborea L. were examined by scanning and transmission electron microscopy and morphometric methods. The lungs contain several interconnected folds in a netlike reticular arrangement of first, second and third order, mainly covered with pneumocytes. On the septa of first and second order, irregularly distributed small patches of ciliated epithelium devoid of goblet cells are located. Dome-shaped neuroepithelial bodies can be seen in the vicinity of ciliated epithelium. The pulmonary epithelium consists of one type of pneumocyte, which contain in their cytoplasm three kinds of bodies: lamellar, dense and multivesicular. The dense bodies are precursors of lamellar bodies (LBs), while the multivesicular bodies are incorporated into the LBs, being later secreted to the air space. The lining layer covering the internal lung surface contains numerous transformed LBs but tubular myelin figures are scarce. The surface of the lining layer is coated by a thin film. The air-blood barrier, consisting of three layers: epithelium, interstitial space and endothelium, is 0.6 μm thick.
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  • 59
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    Acta neuropathologica 69 (1986), S. 81-90 
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jacob disease ; Slow virus infection ; Subacute spongiform encephalopathy ; Ultrastructure ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Guinea pigs inoculated with brain homogenate from serially passaged Creutzfeldt-Jakob disease (CJD) were killed biweekly starting at week 2 until terminal illness (about 200 days following inoculation). A mild swelling of postsynaptic dendrites and an increase in the number of glial filaments in astrocytic processes was seen at week 4, followed by increased swelling and lucency of axons and dendrites by week 6 post inoculation (p.i.). Severe undulation and focal interruptions of synaptic membranes were also observed both at weeks 4 and 6. By week 8, one could see cystically dilated cellular processes. These sometimes showed continuity with adjacent swollen processes through focally disrupted plasma membranes, and most likely represent a progressive enlargement of vacuoles through fusion and subsequent addition of adjoining processes. The spongiform changes increased mildly between week 8 and week 10 and remained essentially the same in subsequent weeks. After week 24 there was a sharp increase in both the number and size of vacuoles. At week 24 severe structural alterations were present both in the neurons and astrocytes, and numerous intranuclear inclusions were demonstrated in many neuronal nuclei. This study shows that morphological changes in the brain occur considerably earlier than the clinical manifestations of the disease. In the early phase of the disease, there were significant alterations on the dendrites and synapses.
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  • 60
    ISSN: 1432-0533
    Keywords: Streptozotocin-diabetic rat ; Myenteric plexus ; VIP-ergic nerves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Enteric nerves in the ileum of rats 8 weeks after streptozotocin-induction of diabetes were examined under the electron microscope before and after immunolabeling for vasoactive intestinal polypeptide (VIP). These studies have provided evidence of degenerative changes in the myenteric nerve fibres of diabetic rats, many of which were shown to contain VIP. It is suggested that VIP-ergic nerves in the gut may play a role in the developent of gastrointestinal dysfunction in diabetes.
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  • 61
    ISSN: 1432-0533
    Keywords: Brain tumor ; Rhabdomyosarcoma ; Immunohistochemistry ; Ultrastructure ; Cerebral paragonimiasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A necropsy case of a primary rhabdomyosarcoma with chronic paragonimiasis in the cerebrum of a 68-year-old man is reported. The clinical data showed a right hemiplegia and dysarthria which became lethal in 6 months even though operation and radiation therapy were performed. Computed tomography revealed a large low-density area associated with the peripheral enhancement in the left basal ganglia, and multiple conglomerated calcified masses in the left temporal and occipital lobes. Biopsied and necropsied materials of the tumor in the basal ganglia was reddish brown in color and histologically was composed of purely mesenchymal derivatives with both embryonal and mature striated muscle cells but neither neuronal nor glial elements. Some of the tumor cells with extending slender cytoplasms showed obvious cross striations at the light and electron microscope levels and immunohistochemical reactivity for myoglobin. All tumor cells were also positive for vimentin, but not for glial fibrillary acidic protein. The clinical and necropsy findings revealed no primary lesion anywhere but in the brain. In addition, numerous dead oval eggs ofParagonimus westermani were found in many cystoid lesions encapsulated by thick connective tissues with calcification and/or ossification. Clinicopathological features of 24 cases of primary rhabdomyosarcoma of the central nervous system reported in the literature are reviewed briefly. The histogenesis of this tumor are discussed together with comments on cerebral paragonimiasis.
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  • 62
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    Archives of dermatological research 279 (1986), S. 77-82 
    ISSN: 1432-069X
    Keywords: Lichen nitidus ; Lichen plahus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lichen nitidus (LN) and lichen planus (LP) are considered by some investigators to be two variants of the same disease, and by others to be two distinct dermatoses. In order to obtain further information about the relationship between LN and LP we examined the ultrastructure of lesions from two LN patients. In the central part of the lesion, the basement membrane was absent, or was interrupted by migrating phagocytes or lymphocytes. The basal cells and the lower cells of the stratum spinosum exhibited karyolysis and appeared to be compressed and often necrotic. In the upper dermis irregular cell debris full of clumps of tonofilaments and colloid-body-like structures was observed. A dense dermal infiltrate of macrophages, lymphocytes, fibrocytes, and Sezary-like cells was present. Signs of cooperation between lymphocytes and macrophages were also evident. The periphery of the lesion showed no pathological features except for enlargement of the intercellular spaces and the presence of mononuclear cells scattered through the epidermis. Several normal Langerhans cells were noticed. These ultrastructural findings were quite similar to those reported for LP.
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  • 63
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    Cellular and molecular life sciences 42 (1986), S. 144-147 
    ISSN: 1420-9071
    Keywords: Ultrastructure ; catalase ; D-amino acid oxidase ; fetal mouse liver ; hepatocytes ; peroxisomes ; muscular dysgenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the hepatocytes of ‘normal’ fetal mice from mothers which were carriers of muscular dysgenesis, catalase and D-amino acid oxidase (DAAO) positive as well as negative peroxisomes were observed. DAAO reaction product was occasionally localized in patches around cell membranes and DAAO-positive peroxisomes were frequently observed near mitochondria.
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  • 64
    ISSN: 1432-1106
    Keywords: Optic tectum ; Neurotransmitters ; Cholinergic markers ; Ultrastructure ; Goldfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurochemical parameters associated with cholinergic and excitatory amino acid transmission, were measured in synaptosomes of the goldfish optic tectum at different times after unilateral eye ablation. Significant decreases in choline acetyltransferase and acetylcholinesterase were measured 12 and 30 days after enucleation. The high affinity choline uptake did not parallel the decrease in cholinergic enzymes. Instead there was a significant increase of the uptake per unit of protein (though not relative to the total number of tectal synaptosomes). No decrease of the high affinity D-3H aspartate uptake was measured in the deafferentated optic tectum. Electron microscopic observations showed a correspondence between the time course of cholinergic enzyme decrease and the degeneration of retinal afferents to the tectum. The present results support the notion that acetylcholine is a better candidate than the excitatory amino acids for a neurotransmitter role in the fish optic tectum.
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  • 65
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    European journal of pediatrics 144 (1986), S. 557-562 
    ISSN: 1432-1076
    Keywords: Rimmed vacuoles ; Childhood ; Myopathy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 5-year-old boy suffered from a slowly progressive non-familial neuromuscular disease, clinically marked by generalised muscle weakness, atrophy and hypotonia, a “myopathic” EMG and mildly elevated CK values. His gastrocnemius muscle showed marked myopathy, type I fibre predominance, and numerous “rimmed” vacuoles. This boy's condition is regarded as a childhood neuromuscular disease with rimmed vacuoles.
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  • 66
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    Child's nervous system 2 (1986), S. 297-300 
    ISSN: 1433-0350
    Keywords: Pineocytoma ; Magnetic resonance imaging ; Computed tomography ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The radiological and pathological findings in three children with pineocytomas are described. The patients presented with symptoms and signs of increased intracranial pressure. CT scans demonstrated obstructive hydrocephalus, but failed to visualize pineal masses that were subsequently seen on MR scans. A suboccipital, supracerebellar approach was used to obtain tissue for histological diagnosis and, in one case, achieve a total removal. Light microscopy demonstrated typical pineocytomatous rosettes without evidence of gangliocytic or astrocytic differentiation. Electron microscopy revealed numerous dense core vesicles with synaptic ribbons, suggesting neurosecretory capability. These three cases demonstrate the diagnostic advantage of MR imaging for tumors in the pineal region as well as the relatively well-differentiated histopathological characteristics of pineocytomas.
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  • 67
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    Virchows Archiv 409 (1986), S. 163-169 
    ISSN: 1432-2307
    Keywords: Thymoma ; Thymic carcinoma ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of thymic carcinoma arising within a lymphocyte rich thymoma is reported. The undifferentiated carcinoma contained cellular elements resembling choriocarcinoma but could be differentiated there-from by positive staining for prekeratin antigen and an absence of staining for B-HCG antigen utilizing immunohistochemical techniques.
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  • 68
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    Theoretical and applied genetics 72 (1986), S. 840-844 
    ISSN: 1432-2242
    Keywords: Chlorophytum comosum ; First pollen mitosis ; Male plastid inheritance ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The behaviour of plastids and mitochondria during the formation and development of the male gametophyte of Chlorophytum comosum has been investigated using electron microscopy. During first pollen mitosis an intracellular polarization of plastids occurs in that the plastids are clustered in the centre of the microspore. The originating generative cell normally lacks plastids. Only in a small number of microspores have plastids been observed near the dividing nucleus of the microspore and later on in the generative cell. These observations agree with the genetic investigations of Collins (1922) on the mode of plastid inheritance which demonstrated a small amount of biparental plastid inheritance in Chlorophytum. The cytological mechanisms underlying plastid polarization during the first pollen mitosis are discussed.
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  • 69
    ISSN: 1432-0878
    Keywords: Glucocorticoids ; Cartilage ; Growth ; Histochemistry ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of different doses of various steroids on growth, and on costal and epiphyseal chondrocytes, have been studied in prenatal, immature, and adult Long-Evans rats using histochemical techniques, and both light and electron microscopy. Both prenatal and postnatal treatments have been employed. The steroids used were cortisone (CA), betamethasome (BM), and, in the prenatal group only, dexamethasone (DM). Body weight is reduced in all treated rats (except the low dose of CA) by day 17 of gestation, with greater weight reductions occurring in rats receiving the higher dose level of each steroid. In rats treated prenatally or neonatally, and sacrificed postnatally on days 39–43 or days 116–127, body weights, and tibial and tail lengths, are less than in correspondingly aged controls, thus showing a persistence of the effects of treatment. Costal and epiphyseal cartilages in prenatal rats show cellular, synthetic, and ultrastructural alterations induced by treatment with glucocorticoids but the responses are not necessarily comparable. Except for the low dose of DM, the higher doses of each steroid are more effective in inhibiting, or altering, growth and cellular differentiation in the developing fetuses. Surprisingly, a low dose of DM has a more devastating effect on the cells and extracellular matrix of both costal and epiphyseal cartilage, than do higher dose-levels of the various steroids. Low doses of CA and BM are also effective in inhibiting or altering growth and cellular differentiation, but their effectiveness is largely limited to 17 days of gestation. The order of effect of the various doses of the different steroids on fetal cartilage, listed in decreasing order of severity, is as follows: 0.12 DM, 0.24 DM, 0.42 BM, 50 CA, with 25 CA and 0.18 BM being approximately equal and only slightly different from control cartilages. The effect of prenatal or neonatal glucocorticoid treatment on chondrocytes is minimal in the 30–43 day, or 116–127 day, postnatal groups. In immature and adult rats, cortisone affects the chondrocytes more deleteriously than does betamethasone, and a 5.0 mg dose of CA seems to affect chondrocytes, body weight, and tibial and tail lengths more than 0.2 or 7.5 mg doses.
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  • 70
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    Cell & tissue research 244 (1986), S. 457-466 
    ISSN: 1432-0878
    Keywords: Microthrix ; Microvillus ; Ultrastructure ; Fixation ; Tapeworm ; Hymenolepis diminuta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of microtriches of the rat tapeworm, Hymenolepis diminuta, was examined with a number of electron-microscopic techniques. Fixatives containing different buffers, non-ionic detergents, chelators, tannic acid and various concentrations of aldehydes were tested for ability to stabilize cytoskeletal components while extracting background material. These methods revealed features unique to these specialized microvilli, and permitted construction of a detailed model of microthrix architecture. The microtriches of H. diminuta are comprised of a microfilament-containing base, a dense cap and a complex junctional region between the base and cap. The microfilaments of the base are contiguous distally with a tubular structure (the junctional tubule) within the junctional region; proximally, the microfilaments end abruptly: a terminal web appears to be absent. A beveled bilayered cylinder of dense material (the core tunic) encircles the microfilamentous core. The core tunics and junctional tubules of the microtriches are specifically and uniformly aligned along the strobila. Microtriches therefore can be distinguished from other microvilli (e.g., those of enterocyte brush borders) by their complex ultrastructure and precise orientation upon the cytoplasmic surface.
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  • 71
    ISSN: 1432-0878
    Keywords: Duodenum ; Cholecystokinin ; Gastrin ; Immunocytochemistry ; Ultrastructure ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Human duodenal endocrine cells reactive with antibodies to cholecystokinin (CCK) 33 (10–20) and/or gastrin 34 (1–15) were studied by a combination of immunohistochemical and electron-microscopic methods. By immunohistochemistry, three types of endocrine cells were distinguished in human duodenal mucosa, i.e., those only positive for only CCK, those positive for both CCK and gastrin and those only positive for only gastrin. Ultrastructurally, the first cell type is characterized by many secretory granules with an eccentric dense core (mean diameter; 271+-74 nm). The second cell type, which was less frequent than the other two, has ultrastructural features that resemble type-I cells. The last cell type was composed of two types of cells containing small secretory granules identical to those of IG cells (mean diameter; 171+-31 nm) or large secretory granules indistinguishable from those of I cells (mean diameter; 286+-50 nm).
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  • 72
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    Cell & tissue research 246 (1986), S. 39-44 
    ISSN: 1432-0878
    Keywords: Ultimobranchial glands ; Cysts ; C-cells ; Ultrastructure ; Chicken (Gallus gallus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultimobranchial glands of the chicken were examined by electron microscopy and immunocytochemistry using a calcitonin antiserum. Electron microscopy confirmed the presence of C-cells, containing numerous secretory granules storing calcitonin, in the luminal lining of cyst-like structures found in these glands. These cells were furnished with prominent microvillar projections at their luminal surface, and the cytoplasm of the apical region was filled with fibril material. Furthermore, the cells contained prominent junctional complexes and desmosomes at their apico-lateral surfaces. In these C-cells, secretory granules were concentrated near the lumen and some were attached to the apical cell membrane. The luminal content of the cysts had a colloid-like and flocculent appearance, and was frequently seen attached to the cytoplasmic projections or apical cell membrane of the C-cells. Since the cysts progressively increase in volume and number with age, it is suggested that they may partly play a role in the storage of excess or unneeded hormonal products.
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  • 73
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    Cell & tissue research 245 (1986), S. 91-100 
    ISSN: 1432-0878
    Keywords: Testis ; Leydig cells ; Crystalloids ; Ultrastructure ; Rat, Rattus fusdpes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Leydig cells in a seasonally breeding rodent, Rattus fuscipes, was studied in the breeding and non-breeding season and compared with Leydig cell morphology after suppression of gonadotrophin secretion induced by hypophysectomy or chronic administration of testosterone. Serum luteinizing hormone (LH) and testosterone (T) were measured and in-vitro T production by testes was assessed by stimulation with human chorionic gonadotrophin (hCG). In non-breeding wild-trapped rats and rats with experimental suppression of gonadotrophins, the Leydig cells were atrophied and exhibited variable amounts of cytoplasmic lipid and crystalloid inclusions, the latter commonly dominating the cytoplasmic area. Compared with fertile rats, serum LH and hCG-stimulated T production of experimentally regressed rats was significantly reduced, confirming structural features indicative of Leydig cell inactivity. Atrophy of Leydig cell nuclei was accompanied by the formation of unusual intranuclear vesicles sometimes containing small crystalloids. Ultrastructural analysis suggested transfer of the vesicles to the cytoplasm where their unification gave rise to much larger crystalloid bodies. Crystalloids occurred when serum LH was depressed and with either full (T treatment) or arrested spermatogenesis (hypophysectomy) suggesting that their formation is governed by pituitary function and is not dependent upon the degree of spermatogenic activity.
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  • 74
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    Cell & tissue research 246 (1986), S. 607-621 
    ISSN: 1432-0878
    Keywords: Rod photoreceptor ; Light damage ; Albino rat ; Ultrastructure ; Reversible change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The temporal sequence of ultrastructural changes induced in the rat rod photoreceptor by 80 lux light-stress has been studied. The changes seen were compared with those produced by a much dimmer (3 lux) illumination. Some of the early signs of abnormality were (1) degradation of some disk membranes at the tips of outer segments, (2) disaggregation and detachment of ribosomes, (3) lighter matrices in swollen mitochondria, (4) disappearance of the Golgi apparatus, (5) proliferation of autophagic bodies in the inner segments, and (6) appearance of perimitochondrial membrane whorls in the synaptic terminals. No single change could be identified that would inexorably lead to cell death. The overall picture, however, suggested that an inability of the cell to maintain its anabolic balance is responsible for the pyknosis that occurs when the 80 lux exposure exceeds 12–15 h. All changes were reversible when exposure duration did not exceed 12 h, the normal length of the light cycle for these rats.
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  • 75
    ISSN: 1432-0878
    Keywords: Smooth-muscle cell ; Cell culture ; Ultrastructure ; Optical measurement ; Cell contraction ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In numerous investigations using cultured smooth-muscle cells, investigators have consistently added 10–20% fetal calf serum (FCS) to the medium to maintain viable cells. In the present study we utilized an optical technique to investigate whether smooth-muscle cells, cultured with or without FCS, maintain their contractile activity in vitro. With such optical measurement, we were able to detect signals due to spontaneous contractions, in muscle cells cultured in FCS-free medium for up to 8 days, and, for the first time, were also able to observe the conduction of these cell contractions. The ultrastructural characteristics of cultured smooth-muscle cells during contractile activity, were also examined by electron microscopy. The cells were mature and well-differentiated, and were packed with numerous myofilaments. They had developed long cell processes, and were linked to one another by gap junctions. These observations indicated that the smooth-muscle cells, cultured without FCS for 7 to 8 days, were morphologically mature and maintained their contractile activity, whereas the cells cultured in FCS-containing medium showed no detectable signs of contractile activity.
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  • 76
    ISSN: 1432-0878
    Keywords: Chemoreceptor ; Ultrastructure ; Parasitic copepod crustacean ; Pachypygus gibber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The topography, external structure and ultrastructure of a cephalic sense organ, described for the first time, were studied by light and electron microscopy in the parasitic copepod Pachypygus gibber. This species is unusual in that it has three reproductive sexual forms (two males, one female).The cephalic organ, present only in the atypical male, is made up of numerous functional units, each composed of 4 cells: two sensory cells, one basal enveloping cell and one apical canal-forming cell opening outside via a pore. Many hundred pores are situated within the cuticle of the ventral pleural borders. Through each pore protrude two ciliary endings. An interesting feature is that the ciliary ends are without cuticular cover and thus, directly exposed to the surroundings, a situation unique in arthropods. The structural characteristics of this sense organ and the particular mode of life of the atypical male (with an additional free planktonic phase), lead to the hypothesis that its function is linked to chemical reception in the complex behavioural patterns such as host and sex recognition, during the free life.
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  • 77
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    Cell & tissue research 245 (1986), S. 457-460 
    ISSN: 1432-0878
    Keywords: Anterior pituitary ; Somatotroph ; Lactotroph ; Ultrastructure ; Immunocytochemistry ; Fetal and neonatal rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of immunoreactive somatotrophs and lactotrophs in pituitaries of fetal rats at 19, 20 and 21 days of gestation and on the day of birth was studied. Somatotrophs, first detectable at 19 days of gestation, undergo only minor modifications before reaching the structure described for adults. In particular there is an increase in the endoplasmic reticulum and Golgi apparatus. Lactotrophs, first identifiable in newborn rats, are very different in ultrastructure from adult cells, because the secretory granules are generally small, but variable in shape and size, and the Golgi complex is prominent.
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  • 78
    ISSN: 1432-0878
    Keywords: Organ culture ; Amelogenesis ; Dentinogenesis ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Molar tooth germs from three-day-old rats were cultured successfully for fourteen days, permitting the study of the development in vitro of both extracellular matrix and cellular elements such as odontoblasts and ameloblasts. The ultrastructure of the cultured tooth germs was compared with the ultrastructure of tooth germs in vivo at a comparable developmental stage. Progenitor cells of odontoblasts and ameloblasts were found to differentiate in vitro. Odontoblasts seemed to contain more lysosome-like bodies and fewer secretory granules than in vivo. They formed normally mineralizing dentine or a thick layer of dense, unmineralized predentine with incidentally some amorphous, extracellular material. Enamel was exclusively present opposite well developed dentine. It was often hyperor hypomineralized and enamel rods were not as regularly shaped as in vivo. In places where no enamel formation had taken place, large amounts of amorphous extracellular material were sometimes seen. From these observations it can be concluded that cellular development in cultured tooth germs appeared more or less normal, but extracellular matrix formation and mineralization were sometimes disturbed.
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  • 79
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    Cell & tissue research 244 (1986), S. 165-171 
    ISSN: 1432-0878
    Keywords: Iridophores ; Motility ; Innervation ; Ultrastructure ; Teleost (Odontobutis obscura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Reflecting chromatophores in the dermis of the skin of a freshwater goby, Odontobutis obscura, are of an iridophore type. These chromatophores contain numerous reflecting platelets, which are similar to those in iridophores of other fish and amphibian species. It was found that these iridophores are motile, i.e., these cells respond to certain stimuli with translocation of the platelets within the cells. K+ ions induced dispersion of the platelets in excised scale preparations, but not in excised scales from chemically denervated fish. Norepinephrine and melatonin also induced dispersion of the platelets. Alpha-MSH was effective in aggregating these organelles into the centrospheres of the cells. The conclusions reached are: (1) iridophores of O. obscura are motile; (2) the movement of the iridophores is under nervous and hormonal control.
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  • 80
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    Cell & tissue research 243 (1986), S. 405-414 
    ISSN: 1432-0878
    Keywords: Leydig cells ; Ethane dimethanesulphonate ; Ultrastructure ; Destruction ; Gonadotrophins ; Testosterone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cytotoxic effects of ethane dimethanesulphonate upon rat Leydig cells were examined ultrastructurally up to 3 days after treatment and related to changes in serum levels of gonadotrophins and testosterone. Six hours after administration of ethane dimethanesulphonate the usual tubulo-vesicular morphology of Leydig-cell smooth endoplasmic reticulum was converted to small vesicles and the Golgi apparatus showed focal hypertrophy into anastomosing tubules. These changes became more marked by 12 h with many Leydig cells exhibiting karyopyknosis and hyperchromatism. Necrotic Leydig cells were often engulfed by macrophages, the latter containing pyknotic fragments of Leydig cells within their cytoplasm. One day after administration, advanced necrosis of Leydig cells occurred, many of which were phagocytosed by macrophages, and on day 3, destruction of Leydig cells was complete resulting in their elimination from the interstitial tissue, which contained only loose connective tissue and macrophages. Structural alterations to the Leydig cells from 6–24 h was reflected by a significant reduction in serum testosterone levels which further declined to the limits of detection accompanying the abolition of Leydig cells on day 3. These changes were paralleled by a significant elevation of serum LH and FSH levels suggesting diminished feedback regulation of pituitary gonadotrophin secretion. The results indicate that ethane dimethanesulphonate is a rapidly acting Leydig cell toxin which may be a useful experimental tool in further studies of spermatogenic function mediated via Sertoli cell-Leydig cell interaction.
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  • 81
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    Cell & tissue research 244 (1986), S. 493-499 
    ISSN: 1432-0878
    Keywords: Endothelium ; Capillaries ; Kidney ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A new endothelial cell structure, named the endothelial pocket, has been found by combined transmission and scanning electron microscopic studies of renal peritubular capillaries. Transmission EM observations made on these and other fenestrated capillaries demonstrated that each pocket consists of an attenuated fold of fenestrated endothelium that projects 200 nm into the lumen above the rest of the endothelial surface. Beneath this luminal fold, there is a space and then another layer of fenestrated endothelium which abuts the basal lamina. The linear density of endothelial pockets was measured in the capillaries of the kidney cortex, intestinal mucosa and exocrine pancreas in mice and determined to be 0.067, 0.017 and 0.007 pockets·μm-1 respectively. Cationic ferritin decoration of the anionic sites on the luminal surface of the endothelium in these capillary beds revealed that both unlabelled and labelled diaphragms are clustered. In such specimens, the majority of the luminal diaphragms on endothelial pockets did not have cationic ferritin binding sites detectable by either scanning or transmission EM. On this account as well as on account of their general morphology, endothelial pockets appear to be multifold versions of the simple transendothelial channel.
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  • 82
    ISSN: 1432-0878
    Keywords: Capillary ; Epithelium ; Retina ; Retinal pigment epithelium ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light- and urethane-induced retinopathies in rats are characterized by loss of photoreceptors. Retinal capillaries subsequently become incorporated into the normally avascular retinal pigment epithelium. These models provided an opportunity to study the response of epithelial cells to closely apposed capillaries, in order to determine if capillaries contribute to the polar organization of epithelial cells. Pigment epithelial cells reorganized their lateral plasma membrane where the latter faced intraepithelial capillaries. This normally flat, undifferentiated membrane developed attachment sites, folds and intracytoplasmic tubules, and exhibited endocytosis and putative basal lamina secretion. These structural and functional specializations are normally restricted to the basal plasma membrane — the normal vascular front of the cell facing the dense meshwork of capillaries constituting the choriocapillaris. We conclude that RPE cells, and perhaps epithelia in general, polarize in response to an adjacent capillary bed.
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  • 83
    ISSN: 1432-0878
    Keywords: VIP ; Nerve fibers ; Ganglion cells ; Chromaffin cells ; Ultrastructure ; Adrenal gland ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary VIP-like immunoreactivity was revealed in a few chromaffin cells, medullary ganglion cells and a plexus of varicose nerve fibers in the superficial cortex and single varicose fibers in the juxtamedullary cortex and the medulla of the rat adrenal gland. VIP-like immunoreactive chromaffin cells were polygonal in shape without any distinct cytoplasmic processes and they appeared solitarily. Their cytoplasm contained abundant granular vesicles having a round core and the immunoreactive material was localized to the granular core. VIP-immunoreactive ganglion cells were multipolar and had large intracytoplasmic vacuoles. The immunoreactive material was localized not only in a few granular vesicles but also diffusely throughout the axoplasm. VIP-immunoreactive varicose nerve fibers in the superficial cortex were characterized by abundant small clear vesicles and some large granular vesicles, while those in the juxtamedullary cortex and medulla and the ganglionic processes were characterized by abundant large clear vesicles, as well as the same vesicular elements as contained in the nerves in the superficial cortex. The immunoreactive material was localized on the granular cores and diffusely in the axoplasm in both nerves. Based on the similarity and difference in the composition of the vesicles contained in individual nerves, it is likely that the VIP-immunoreactive nerve fibers in the medulla and the juxtamedullary cortex are derived from the medullary VIP-ganglion cells, while those in the superficial cortex are of extrinsic origin. The immunoreactive nerve fibers in both the cortex and the medulla were often in direct contact with cortical cells and chromaffin cells, where no membrane specializations were formed. The immunoreactive nerve fibers were sometimes associated with the smooth muscle cells and pericytes of small blood vessels in the superficial cortex. In addition they were often seen in close apposition to the fenestrated endothelial cells in the cortex and the medulla, only a common basal lamina intervening. Several possible mechanisms by which VIP may exert its effect in the adrenal gland are discussed.
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    Cell & tissue research 243 (1986), S. 137-144 
    ISSN: 1432-0878
    Keywords: Lung ; Blood-air barrier ; Surfactant ; Ultrastructure ; Freeze fracture ; Birds ; Penguin (Aptenodytes forsten)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Of all avian species the emperor penguin is the best adapted bird to attain the greatest diving depths and diving durations. Therefore the lung of this bird was investigated with electron-microscopic, i.e., freeze-fracture and thin-section methods. The parabronchi are surrounded by bundles of smooth muscle cells innervated by varicosities of autonomic nerves. The parabronchial epithelium is flat, bears a few microvilli and does not show any conspicuous ultrastructural specializations; only individual cells contain secretory granules. The atrial epithelial cells bear apical microvilli and are interconnected by adhering and tight junctions (5–10 sealing strands), the latter presumably forming an effective barrier against paracellular fluid movements. The cells contain lamellar inclusions of two types: (i) round membrane-bounded granules, the lamellar content of which is fixation-labile, and (ii) large polymorphic compact deposits of well-preserved lamellae. In both types of inclusions the individual lamellae can be of trilaminar appearance, whereas their fracture faces are smooth. Lamellar material also covers the epithelium of atria, infundibula and air capillaries. In thin areas the diameter of the morphological blood-air barrier measures 220–330 nm. Usually the endothelium of the blood capillaries is thicker (40–180 nm) than the air capillary epithelium (25–150 nm). Both epithelium and endothelium are interconnected by tight junctions, which seem to be more extensive and presumably tighter in the epithelium than in the endothelium. Frequently the common basal lamina is the thickest individual component of the blood-air barrier, measuring between 170–230 nm. Often collagen fibrils occur in this area of the barrier. In comparison with that of other birds the entire blood-air barrier of the emperor penguin is relatively thick, probably owing to an adaptation of the lung tissue which must resist high hydrostatic pressure during diving excursions.
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  • 85
    ISSN: 1432-0878
    Keywords: Parathyroid gland ; Protein A-gold technique ; Ultrastructure ; Storage granules ; Mammals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic immunocytochemistry for the demonstration of parathormone in parathyroid chief cells was performed in adult male rats, gerbils, mice, and dogs, using the protein A-gold technique. Protein A-gold particles were detected over both large and small secretory granules in all the animals examined. In the former, they were concentrated not only over type-I granules with a large core, but also over type-II granules with a small core. They were also located over atypical granules, including heterogeneously dense granules, granules having vesicles in a finely particulate core, and distorted granules. All labelled secretory granules were characterized by the presence of a clear halo of varying width around the core. Occasionally, Golgi cisternae as well as Golgi vacuoles with a finely particular content were also labelled. The labelling of the secretory granules was strong in dogs, moderate in rats and gerbils, and weak in mice. In addition, it was more intense in the non-osmicated preparations than in the osmicated preparations. The frequency of both types of large granules showed species differences. The possible factors involved in these differences are discussed.
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  • 86
    ISSN: 1432-0878
    Keywords: Peripolar cells ; Juxtaglomerular apparatus ; Kallikrein ; Ultrastructure ; Mammals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peripolar cells are granulated glomerular epithelial cells that form a cuff around the vascular pole of the glomerulus. Quantitation of these cells in 17 species of mammals (including man, several laboratory animals and a variety of other species) indicated that they were detectable by light microscopy in all but one of the mammals that were examined (the Australian hopping mouse). In adult mammals with detectable peripolar cells, the “peripolar cell index” (the percentage of randomly sectioned glomeruli that displayed peripolar cells in histological sections of kidney) ranged from 0.15 (for echidna) to 11.86 (for sheep). Newborn lambs and rats showed strikingly high values (23.30 and 10.76, respectively) compared with their adult counterparts. Using electron microscopy, peripolar cells were observed in all species that were examined, including the Australian hopping mouse. Morphologically, peripolar cells were similar in all species although their size and granule population varied. They showed a predominantly outer cortical glomerular distribution and a close anatomical relationship with the renin-containing myoepithelioid cells. These findings indicate that peripolar cells are present in a wide variety of species and support the view that such cells may play a significant role in the regulation of normal renal function.
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  • 87
    ISSN: 1432-0878
    Keywords: Uterus ; Epithelium ; Ultrastructure ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the endometrial epithelium of the pig was studied during the estrous cycle and early pregnancy up to implantation. Special attention was given to the luminal epithelium and morphological indications of protein synthesis. Although the general morphology of the luminal and glandular epithelia is similar (both tissues consist of secretory cells and ciliated cells at all the stages studied), it appears that the two epithelia should be considered as two functionally different units in the pre-implantation period. Morphological evidence suggests the presence of at least three different secretory products within luminal epithelial cells; they are released at different times, i.e. at estrus, between day 8 and 10 and after day 11. The glandular epithelium shows release of secretory products from day 10–11. Increasing amounts of glycogen were found within epithelial cells, especially in pregnant gilts from day 12. The possible significance of secretory activity of the epithelium is discussed in relation to the development of the embryos.
    Type of Medium: Electronic Resource
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  • 88
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    Plant systematics and evolution 153 (1986), S. 259-264 
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Angiosperms ; Pteridosperms ; Caytoniales ; Caytonanthus ; Ultrastructure ; pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pollen grain wall structure ofCaytonanthus arberi was studied with SEM and TEM. The monosulcate, bisaccate pollen grain of this taxon has an alveolar wall structure that is more like that found in saccate Conifers than primitive Angiosperms. Pollen grain morphology does not support a Caytonialean ancestry for the Angiosperms.
    Type of Medium: Electronic Resource
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  • 89
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    Plant systematics and evolution 154 (1986), S. 31-39 
    ISSN: 1615-6110
    Keywords: Angiosperms ; Lactoridaceae ; Ultrastructure ; pollen ; fossil pollen (Cretaceous)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pollen wall ultrastructure of the primitive AngiospermLactoris fernandeziana Phil. (Lactoridaceae) is described. The monosulcate aperture, granular wall structure and sacci (all primitive features) suggest placement of this family in theMagnoliales. Pollen ofLactoris is compared to fossil dispersed pollen from the Lower and lower-Upper Cretaceous. The fossil pollen shares characteristics which are restricted to theLactoridaceae suggesting that this family was present during the early Cretaceous.
    Type of Medium: Electronic Resource
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  • 90
    Electronic Resource
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    Springer
    Protoplasma 131 (1986), S. 1-10 
    ISSN: 1615-6102
    Keywords: Cell division ; Lomentaria ; mitosis ; Red algae ; Rhodophyta ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitosis in the marine red algaLomentaria baileyana (Rhodymeniales, Rhodophyta) was studied with the electron microscope. Nucleus associated organelles known as polar rings (PRs) migrate to establish the division poles at prophase. At prometaphase, shallow invaginations in the nuclear envelope (NE) form on two sides of each PR and soon rupture. The gaps that are consequently formed contain several small fragments of NE. A larger region of NE remains intact between the two gaps. By metaphase several cisternae of perinuclear endoplasmic reticulum (PER) have enclosed most of the nucleus but remain absent from the polar regions. The nucleolus disperses partially and a typical metaphase plate of chromosomes is formed. Each PR has disjoined into separate proximal and distal portions. MTs converge widely on all regions of the polar area, but do not extend into the cytoplasm. Some MTs end near or at the chromosomes while others extend slightly farther past the chromosomes or diagonally to the NE. As chromosomes move to opposite poles at anaphase, they are accompanied by nucleolar material. An interzonal midpiece (IZM) is created as the pole to pole distance increases and the NE remains intact except for the polar gaps. Following detachment from the IZM, the daughter nuclei are separated by a large central vacuole as a cleavage furrow develops and eventually constricts to form two cells following pit connection formation. It is suggested that mitosis inLomentaria represents an evolutionary intermediate between that seen in the higher and lower groups of red algae. This conclusion is in agreement with conventional morphological and light microscopic criteria used to placeLomentaria in theRhodymeniales, which is considered to be the next to most advanced order in theRhodophyta.
    Type of Medium: Electronic Resource
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  • 91
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    Protoplasma 134 (1986), S. 154-162 
    ISSN: 1615-6102
    Keywords: Cell division ; Leishmania ; Mitosis ; Ultrastructure ; Kinetoplastida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The interphase nucleus ofLeishmania adleri has clumps of chromatin associated with the nuclear envelope and a large centrally located nucleolus. Prior to mitosis the basal bodies replicate at the cell anterior. Subsequently, dense plaques appear in the equatorial region of the nucleus at the time of spindle development. Microtubules appear in the nucleus adjacent to the nuclear envelope and embedded in the matrix of the plaques. A central spindle composed of a single bundle of microtubules develops and spans the nucleus. Plaques and nucleolar components laterally associate with the spindle and migrate towards the poles. The central spindle elongates to three to four times its original length separating the forming daughter nuclei and producing an interzonal spindle. A remnant of the interzonal spindle remains attached to each of the daughter nuclei until late into cytokinesis. The kinetoplast does not divide until after the completion of mitosis.
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  • 92
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    Protoplasma 131 (1986), S. 166-173 
    ISSN: 1615-6102
    Keywords: Chloroplast development ; Pisum sativum ; Prolamellar body ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We analyzed transformation, recrystallization, splitting and dispersion of prolamellar bodies during chloroplast development in pea seedlings illuminated by white, red and blue light of low intensity. With the help of a stereometric method we determined that there was a significant increase of prolamellar body number and a sharp decrease of their volume in differentiating chloroplast even in the first 2 hours of illumination. Decrease of prolamellar body dimensions was due both to gradual dispersion of its elements into primary thylakoids (indicated by the decrease of total volume of prolamellar bodies in plastid) and to splitting of prolamellar bodies (indicated by the increase of number of promellar bodies in plastid). Red light was more effective in transformation, splitting and dispersion of prolamellar bodies than blue light during the first 8–12 hours. Longer treatment with blue light had a stronger influence on these processes and on complete recrystallization than other light treatments.
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  • 93
    ISSN: 1615-6102
    Keywords: Chlamydomonas ; Endoplasmic reticulum ; Golgi apparatus ; Wall mutants ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural observations on the principal endomembranes (endoplasmic reticulum, Golgi apparatus) of synchronously growing of wild type and mutant (CW 2, CW 15) strains ofChlamydomonas reinhardii have been carried out. The dictyosomes of the Golgi apparatus in all three cases are highly polar in morphology but lack intercisternal filaments. A clear spatial relationship between dictyosomes and endoplasmic reticulum is seen and a transfer of vesicles from the latter to the former is easily visualized. Coated vesicles invariably appear to be restricted to the trans-pole of the dictyosomes. The endoplasmic reticulum adjacent to the cis pole of dictyosomes is considerably hypertrophied in the case of the wild type, only partially so in the mutant CW 2 but not at all in the mutant CW 15. In the wild type this swelling is most extreme during the period of wall deposition and for several hours afterwards. The results are discussed in relation to the biosynthesis and intracellular transport of, particularly O-glycosidically linked, glycoproteins.
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  • 94
    ISSN: 1615-6102
    Keywords: Chloroplast development ; Grana formation ; Pisum sativum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We analyzed the formation of thylakoids and grana during the development of pea chloroplasts, illuminated by white, red and blue low intensity light. The total length of granal and intergranal thylakoids, and the length of granal thylakoids per unit area of plastid section were measured. Initially the greatest increase in length of granal thylakoids and the highest incidence of grana with large thylakoid content occurred in red light. On the other hand, with illumination times of over 12 hours blue light appeared to be more efficient in stimulating grana formation and thylakoid growth.
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  • 95
    ISSN: 1615-6102
    Keywords: Diapensia lapponica ; Mitochondria ; Morphometry ; Seasonal variation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seasonal changes in the mitochondrial ultrastructure were examined in palisade parenchyma cells of a tuft-formingDiapensia lapponica L. collected at monthly intervals in Northern Finland. Quantitative analyses to measure volume and surface densities were conducted during different periods of growth (stages of growth, acclimation, winter period and deacclimation) in the annual cycle. The volume density was highest in the summer and lowest in the spring; the difference was significant with both fixatives used GA and GA/FA. The largest membrane area (the mitochondrial outer membrane and the cristal membranes together) was observed in the summer and autumn, and was significantly less in the winter and spring. This correlated with fewer mitochondria in the spring and a smaller number of cristae in the winter and spring. In the material fixed in GA/FA the distribution of length/width ratios of mitochondria was relatively uniform in all seasons. However, the mitochondrial ultrastructure had the most varied appearance during the winter. Hypertonie GA/FA solution did not cause significant differences either in the ultrastructure or the volume and surface densities of the mitochondria.
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  • 96
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    Protoplasma 135 (1986), S. 102-111 
    ISSN: 1615-6102
    Keywords: Ultrastructure ; Haptoglossa mirabilis ; Differentiation ; Gun cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The most prominent ultrastructural characteristics of the cyst ofHaptoglossa mirabilis are a large centrally-placed nucleus which is partially ringed by three or four parallel cisternae of rough endoplasmic reticulum (r-ER), a centriole pair and single large Golgi complex which occupy the anterior end of the cell, and a population of provacuoles which occupies the posterior. During germination these organelles migrate into a narrow germ tube which subsequently expands to form the gun cell initial. The extracellular components of the attack apparatus (i.e. missile and injection tube) are formed entirely in the developing gun cell; indirect evidence suggests that both the Golgi complex and r-ER are involved in their synthesis. The intra-cellular component of the attack apparatus comprises the posterior, anterior and apical vacuoles. The posterior vacuole forms by fusion and expansion of the original cyst provacuoles; the formation of the anterior and apical vacuoles occurs late in gun cell differentiation and involves fusion of Golgi-derived vesicles.
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  • 97
    Electronic Resource
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    Protoplasma 134 (1986), S. 102-110 
    ISSN: 1615-6102
    Keywords: Isoelectric focusing ; Isolation ; Potato tuber cell walls ; Purification ; Salt extraction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A preparative procedure for cell wall isolation and purification was developed. The purity of the isolated cell walls was judged biochemically by the lack of activity of cytoplasmic marker enzymes and morphologically by examination at both the light and electron microscope levels. The purified cell walls were extracted with various salt treatments and the molecular weight range of most of the extracted proteins was between 14 and 31 kDa. The salt extracted hydrolytic enzymes were basic in nature (pI〉7.0) compared to their cytosolic counterparts (pI〈7.0). Some enzymes were readily extracted from cell walls (β-glucosidase and β-NAcglucosaminidase) with high salt treatment while most of the α-mannosidase activity associated with purified cell walls could not be removed even with sequential high salt treatments.
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  • 98
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    Protoplasma 135 (1986), S. 119-129 
    ISSN: 1615-6102
    Keywords: Differentiation ; Pectin ; Phytophthora ; Surface ; Ultrastructure ; Zoospore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Populations ofPhytophthora palmivora zoospores induced to undergo synchronous differentiation by the addition of pectin showed an ordered sequence of surface changes. Within 10 seconds “blebs” and “microvilli” appeared on the cell and flagellar surfaces. These projections gave the zoospore a highly irregular and even convoluted surface for up to 30 seconds poststimulation. Between 30 and 40 seconds, pits appeared on the surface, which began to assume a smoother texture. Zoospores then rounded up and by 4 minutes had assumed an almost spherical form. At this time the surface became wrinkled as though shrinkage had occurred. Germ tubes could be seen emerging from almost all cells by 40 minutes, and as germ tubes enlarged, the cell surface became smooth again but with a fibrous texture. Many zoospores retained their flagella through to the germling stage. When cells were stimulated in iso-osmotic rather than hypo-osmotic media, germ tubes in most cases emerged at or very near the site of flagellar attachment. Differentiation in iso-osmotic media showed the same sequence except that the cells did not assume the spherical shape normally characteristic of cysts and germlings differentiating under hypo-osmotic conditions. Strontium-induced differentiation again followed the same general sequence as desribed above, although the cell surface was noticeably more convoluted and irregular prior to the stage of the formation of pits, and flagella were always shed between 40 seconds and 1 minute. Calcium addition up to 20 seconds after the initiation of differentiation with pectin prevented a high proportion of zoospores from encysting, the cells remained motile, and although the frequency of surface blebs and microvilli increased, pits did not appear. These surface changes are consistent with those expected during stimulus-mediated secretion, and it appears that calcium is able to inhibit differentiation only before the secretory step (pit formation).
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  • 99
    ISSN: 1615-6102
    Keywords: Dark-stress ; Recovery ; Root-nodules ; Soybean ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Root-nodules of soybean plants dark-stressed for 8 days and then allowed to recover for up to 17 days were examined by transmission electron microscopy. Control nodules possessed all the ultrastructural features characteristic of infected and uninfected nodule cells. Minimal changes in the appearance of host cells and bacteroids occurred during the first four days of dark stress. After 8 days of dark stress, damage was observed in the cellular and organelle membranes; however, very few changes were observed in the bacteroids. Nodule structure continued to degrade during the first two days of recovery after which time nodules either recovered or completely degraded. In the former case, structural integrity returned to all nodule cells. In the latter case all structural integrity of the host cell disappeared; however, bacteroids appeared intact suggesting that they remained viable.
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  • 100
    ISSN: 1615-6102
    Keywords: Root meristems ; Cell plate ; Ultrastructure ; 2,6-dichlorobenzonitrile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of 2,6-dichlorobenzonitrile on cytokinesis of meristematic cells of onion root during both treatment and recovery has been studied by electron microscopic techniques. 2,6-dichlorobenzonitrile interferes with cell plate formation in such a way that Golgi apparatus vesicles of treated cells appear to be different than controls and seem to coalesce as anomalous partial cell plates. During recovery, an apparently normal progression of cytokinesis is observed and abnormal portions of the cell plate are retained. Nuclear constrictions are observed frequently during recovery as a result of temporal alterations in cytokinesis. Our results show that 2,6-dichlorobenzo-nitrile induces anomalous and/or incomplete cell plates, which might be caused by an altered function of Golgi apparatus.
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