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  • Ultrastructure  (78)
  • Springer  (78)
  • American Institute of Physics
  • 1985-1989
  • 1980-1984  (78)
  • 1935-1939
  • 1981  (78)
Collection
Keywords
Publisher
  • Springer  (78)
  • American Institute of Physics
Years
  • 1985-1989
  • 1980-1984  (78)
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of differentiating preameloblasts from tooth germs of the permanent dentition ofMacaca mulatta andMacaca arctoides (1981)
    Springer
    Calcified tissue international 33 (1981), S. 603-618 
    Details
    ISSN: 1432-0827
    Keywords: Preameloblasts ; Tooth germs ; Monkey ; Enamel ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cytodifferentiation of inner enamel epithelium and the adjacent connective tissue from the tip of the cervical loop to the initiation of enamel elaboration in twoMacaca species was examined. Ten- to twelve-month-old specimens were fixed by perfusion and the permanent tooth buds were prepared for transmission electron microscopy. At the cervical loop proper, inner enamel epithelium cells have lobed nuclei, a paucity of cytoplasm, and wide extracellular spaces; the basal lamina facing the dental papilla is straight. With increasing distance from the tip of the cervical loop, the following changes occur gradually: (a) preameloblasts elongate from 15 to 45 µm, and their organelles, particularly mitochondria and profiles of rough endoplasmic reticulum, become more numerous; (b) extracellular spaces decrease between preameloblasts starting at the basal (infranuclear) end; (c) the basement membrane becomes convoluted and associated with aperiodic fibers; (d) preodontoblast projections penetrate the aperiodic fibers; (e) collagen fibers subjacent to the basement membrane increase in density, with particularly thick fibers paralleling the aperiodic fibers. These modifications occur within three-fourths of the distance from the tip of the cervical loop to the mineralization front. The condensation of preodontoblasts is followed immediately by predentin synthesis. Concomitantly, the basement membrane breaks down and the aperiodic fibers are engulfed by preameloblasts. Preameloblast projections penetrate junctional predentin, contact mineralized dentin, and enamel synthesis ensues. At this stage the ameloblast is 45 µm long, the nucleus is central or basal, the Golgi apparatus has migrated apically, but the Tomes' process has not yet formed. The results indicate that odontogenesis inMacaca monkeys more closely resembles human odontogenesis than does that in the murine rodents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409498
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural events and kinetics of microcyst germination in the myxomycete Didymium iridis (1981)
    Springer
    Archives of microbiology 128 (1981), S. 384-389 
    Details
    ISSN: 1432-072X
    Keywords: Didymium iridis ; Microcyst ; Excystment ; Germination ; Ultrastructure ; Mycetozoa ; Myxomycetes ; Myxamoeba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microcysts of the myxomycete Didymium iridis were induced to excyst by transfer to 5mM potassium phosphate buffer. After 1 h in suspension, 90% of the microcysts had germinated into myxamoebae distinguishable by phase contrast microscopy and staining with Lugol's iodine. Both pH and osmolarity affected the kinetics of excystment. The rate and extent of excystment were decreased by cycloheximide but remained unaffected by actinomycin D, suggesting a requirement for protein synthesis but not RNA synthesis. Initially, the outer wall layers separated from the inner layer, which gradually expanded and loosened. The protoplast rehydrated and reverted to a vegetative morphology. Excysting cells were characterized by nucleolar inclusions, changes in the nuclear envelope and plasma membrane, appearance of ringed cisternal elements and microbodies in the cytoplasm, and formation of a densely fibrous zone adjacent to the site of emergence. Excysting populations have been classified into characteristic stages: mature, initiated, swollen, and pre-emergent microcysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405917
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
    Details
    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00459520
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  • 4
    Electronic Resource
    Electronic Resource
    Arthrobacter P 1, a fast growing versatile methylotroph with amine oxidase as a key enzyme in the metabolism of methylated amines (1981)
    Springer
    Archives of microbiology 129 (1981), S. 72-80 
    Details
    ISSN: 1432-072X
    Keywords: Arthrobacter ; Facultative methylotroph ; Amine oxidase ; Catalase ; RuMP cycle of formaldehyde fixation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3.) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine-and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formal-dehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417184
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  • 5
    Electronic Resource
    Electronic Resource
    The pineal gland of nocturnal mammals (1981)
    Springer
    Cell & tissue research 216 (1981), S. 253-271 
    Details
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Cell populations ; Bat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pineal gland of the pipistrelle bat two different populations of pinealocytes and glial cells were observed electron microscopically. The pinealocytes of populations I and II differ in their content of metabolically active cell organelles. In the pinealocytes of population I, granular vesicles originating from the Golgi apparatus were found in the perikaryon and especially in the endings of the pinealocyte processes. Granular vesicles appeared to be more numerous in hibernating nulliparous females. The pinealocytes of population II are characterized by the presence of small cytoplasmic vacuoles, probably originating from cisternae of the granular endoplasmic reticulum and containing flocculent material of moderate electron density. The classification of the pinealocytes belonging to population II is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233619
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  • 6
    Electronic Resource
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    The fine structure of the compound eye of the African armyworm moth, Spodoptera exempta walk. (Lepidoptera, Noctuidae) (1981)
    Springer
    Cell & tissue research 216 (1981), S. 333-347 
    Details
    ISSN: 1432-0878
    Keywords: Insect eye ; Retina ; Ultrastructure ; Moth ; Spodoptera exempta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the compound eye of the noctuid moth Spodoptera exempta was investigated by electron microscopy. This eucone superposition eye is composed of about 8000 ommatidia. Each ommatidium is surrounded by six secondary pigment cells showing pigment movement according to the state of adaptation. It contains four crystalline cone cells forming together a crystalline cone and tract, two primary pigment cells, which encompass the crystalline cone, and usually eight retinula cells. On the basis of their rhabdomeric structure, three types of retinula cells can be distinguished. According to the structure of the rhabdom, two types of ommatidia are found in different regions of the eye. The rhabdom of the lobed type, providing more than 80% of ommatidia, is composed of V-shaped rhabdomeres with fanwise arranged microvilli. The rhabdom of the square type, found in a small area in the dorsal region of the eye, consists of triangular rhabdomeres with parallel microvilli. The functional significance of this difference is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233623
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  • 7
    Electronic Resource
    Electronic Resource
    Rhythmic contractions of the ampullar epidermis during metamorphosis of the ascidian Molgula occidentalis (1981)
    Springer
    Cell & tissue research 216 (1981), S. 293-312 
    Details
    ISSN: 1432-0878
    Keywords: Ascidians ; Metamorphosis ; Attachment organs ; Ultrastructure ; Rhythmic contractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ampullae of Molgula occidentalis are hollow, tubular extensions of the epidermis. They are ensheathed by a secreted tunic. When they grow out shortly after settlement, the ampullae spread the tunic over the substratum to form a firm attachment for the sessile juvenile. A simple squamous epithelium forms the thin ampullar walls. A glandular, simple columnar epithelium forms the distal tip of each ampulla. The glandular cells probably secrete the adhesive that attaches the tunic to the substratum. Repetitive, peristaltic contractions pass from the base to the distal end of each ampulla. Microsurgery, time-lapse cinemicrography and TEM have been used to analyze this phenomenon. The contractions are mediated by a layer of 4–8 nm microfilaments in the base of the ampullar epithelium. Each juvenile has 7–9 ampullae which contract at different frequencies. Isolated ampullae continue to contract normally for several days. Thus each ampulla has an intrinsic rhythm. Microsurgical experiments suggest that there is no specific region within an ampulla with unique pacemaker properties. It is proposed that communication via gap junctions allows the coordination of ampullar cells into a well organized peristaltic wave.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233621
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  • 8
    Electronic Resource
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    Secretory granules of B-cells in the synovial membrane (1981)
    Springer
    Cell & tissue research 216 (1981), S. 131-141 
    Details
    ISSN: 1432-0878
    Keywords: Synovial membrane ; Secretory granules ; Ultrastructure ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and cytochemical studies have been made on secretory granules of B-cells (fibroblast-like cells) in the knee-joint synovium. The secretory granules were membrane-bounded spherical or slightly elongated bodies, 150 to 350 nm (average 230 nm) in diameter and had a homogenous matrix with several cores. These granules were found in B-cells of all animal species examined; they were numerous in mice and rats, and few in guinea pigs, rabbits and man. Ultrastructural and cytochemical examinations revealed that the Golgi apparatus was involved in the formation of the secretory granules. Unlike lysosomes, they showed no acid phosphatase activity. The granule matrix was positively stained by Thiéiy's periodic acid-thiocarbohydrazidesilver proteinate technique, and the cores were digested by protease. These findings suggest that the granule matrix contains mucopolysaccharide(s) and/or glycoprotein(s) and the core material is largely proteinaceous in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234549
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  • 9
    Electronic Resource
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    Effects of norepinephrine and dibutyryl adenosine 3′, 5′-cyclic monophosphate on the ultrastructure of pineal cells in monolayer culture (1981)
    Springer
    Cell & tissue research 216 (1981), S. 181-191 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Monolayer culture ; N-acetyl transferase ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To determine how neural influences control the function of the pineal gland, morphological and biochemical relationships after pharmacological treatment have been studied in rat pineal cells in monolayer cultures. Norepinephrine (NE) and dibutyryl cyclic 3′,5′-adenosine monophosphate (dBcAMP) treatment of cells that had been in culture for 5 and 21 days produced a stimulation in the enzyme activity of serotonin N-acetyl transferase, an enzyme important in indole synthesis. NE and dBcAMP also produced morphological changes which were dependent on the time of cells in culture. When 5 day-cultures were treated with NE and dBcAMP, light and dark cells were noted and endoplasmic reticulum increased and became more organized. Only dBcAMP treatment at 5 days produced an increase in dense granules and an elongation of cytoplasmic processes. Treatment of 21 day-cultures with dBcAMP also produced an increase in cytoplasmic processes while treatment with NE produced an increase in the synaptic ribbons and clear vesicles within the processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234553
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  • 10
    Electronic Resource
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    Role of estrogen and androgen in maintaining the preovulatory follicle (1981)
    Springer
    Cell & tissue research 216 (1981), S. 615-624 
    Details
    ISSN: 1432-0878
    Keywords: Rat ; Preovulatory follicle ; Ultrastructure ; Estrogen ; Androgen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of Nitromifene citrate (CI 628), an antiestrogen, and Flutamide, an antiandrogen, on the ultrastructure and viability of the preovulatory follicle and granulosa cells were examined both in vivo and in vitro. In vivo administration of either antihormone induced degeneration within the granulosa cells. In some of the affected granulosa cells, the nuclear material was condensed while the cytoplasm and associated organelles were unaltered. In others, the density of the cytoplasm was reduced, the smooth endoplasmic reticulum was dilated but the nucleus remained unaltered. In vitro, either antihormone reduced granulosa-cell viability but the granulosa cells were twenty times more sensitive to CI 628 than to Flutamide. In addition, exposure to CI 628 induced nuclear condensation without affecting the cytoplasm, while Flutamide induced the deterioration of the cytoplasm without altering the nucleus. These observations suggest that: (1) both estrogen and androgens control the viability of the granulosa cells and thereby the follicle, (2) the action of estrogen and androgen is mediated through receptors within the granulosa cells since these antihormones prevent the nuclear uptake of their respective hormone, (3) the granulosa cells of preovulatory follicles appear to be more dependent on estrogen than on androgen, and (4) each steroid appears to have a specific role in maintaining the granulosa cell; estrogens control the integrity of the nucleus while androgens preserve the cytoplasmic organization of the granulosa cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238656
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  • 11
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    The morphology of the horseshoe crab (Limulus polyphemus) visual system (1981)
    Springer
    Cell & tissue research 216 (1981), S. 655-659 
    Details
    ISSN: 1432-0878
    Keywords: Eye ; Neuroeffector junction ; Octopamine ; Circadian rhythm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Efferent fibers to the compound eye of the horseshoe crab, Limulus polyphemus, not only innervate the various pigment cells, but also invade the eccentric cell dendrite and the retinula cells. This finding provides a structural basis for the coupling of circadian rhythm between the efferents and the receptor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238660
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  • 12
    Electronic Resource
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    Electron-microscopic studies on reaggregate cultures of vascular smooth muscle cells from normotensive and spontaneously hypertensive rats (1981)
    Springer
    Cell & tissue research 217 (1981), S. 225-243 
    Details
    ISSN: 1432-0878
    Keywords: Vascular smooth muscle ; Spontaneously hypertensive rat ; Reaggregate cultures ; Ultrastructure ; Collagen synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascular smooth muscle cells were taken from the aortae of the WKY (normotensive) and SHR (spontaneously hypertensive) strains of rat by enzymatic dispersion and put into reaggregate culture. Initially the cells became individual spheroids having average diameters of 10 μm and surfaces that were either rough or smooth. The cells were far more complex than they appeared on their surfaces; after one day in culture, there was considerable internal variation in these cells. All the cells, whether WKY or SHR, lost the bulk of their cytoplasmic contents (including myofilaments, many mitochondria, and vesicular structures) in the early stages of culture and eventually became flattened. After 14 days in culture, these modified cells collected to form reaggregates that were commonly roughly spherical and several hundred μm in diameter. These reaggregates consisted of peripheral regions made up of several layers of flattened cells overlying cores formed by glia-like networks of cells similar in cytological appearance to the cells at the periphery. The meshes formed in this way contained cellular debris derived from dead cells or extrusion of cellular contents. It appears that SHR cells are quicker to form reaggregates than are WKY cells. Yet the SHR cells retained a rounded conformation after five days, whereas the WKY cells were more flattened and formed a more discrete aggregate at this stage of culture. However, by the fourteenth day of culture, differences between the two cell strains were not so pronounced, as far as could be judged by observations made with scanning and transmission electron microscopy. Both WKY and SHR cells at 14 days appeared highly secretory, possessing large Golgi systems as well as numerous ER cisternae and mitochondria. SHR cells produced greater amounts of connective tissue at all stages of culture than did WKY cells, indicating that a similar difference may contribute to the hypertension which develops naturally in situ in SHR animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233577
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  • 13
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    Ultrastructural study of electrophysiologically identified neurones in the paraventricular nucleus of the rat (1981)
    Springer
    Cell & tissue research 216 (1981), S. 503-512 
    Details
    ISSN: 1432-0878
    Keywords: Paraventricular neurones ; Alcian-blue labelling ; Ultrastructure ; Electrophysiology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characterization of electrophysiologically identified neurones of the rat paraventricular hypothalamic nucleus was performed with extracellular labelling technique. The extracellularly recorded neurones are labelled with an electrophoretic deposit of alcian blue contained in the recording micropipette. The neurone thus labelled takes on a dark and shrunken appearance which enables its detection among neighbouring cells without, however, concealing its main morphological characteristics. 1) Spontaneously firing neurones, invaded by an antidromic action potential elicited by electrical stimulation of the neurohypophysis, were identified as magnocellular cells containing dense-cored vesicles of 200–250 nm in diameter. Dense-cored vesicles were not found in the antidromically activated neurones devoid of spontaneous activity. 2) Trans-synaptically activated neurones in the PVN or in its dorso-lateral edge were small cells devoid of dense secretory vesicles. 3) PV neurones in which neurohypophysial stimulation evoked no response, contained small, dense vesicles (100 nm in diameter) comparable with those found in parvocellular peptidergic neurones.
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    URL: http://dx.doi.org/10.1007/BF00238647
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  • 14
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    Pore canals in the cornea of a functionally specialized area of the honey bee's compound eye (1981)
    Springer
    Cell & tissue research 216 (1981), S. 491-501 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Cornea ; Compound eye ; Honey bee (Apis mellifera)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the cornea in an anatomically and functionally specialized part of the honey bee's compound eye (dorsal rim area) was examined by light microscopy, transmission electron and scanning electron microscopy. Under incident illumination the cornea appears grey and cloudy, leaving only the centers of the corneal lenses clear. This is due to numerous pore canals that penetrate the cornea from the inside, ending a few μm below the outer surface. They consist of (1) a small cylindrical cellular evagination of a pigment cell (proximal), and (2) a rugged-walled, pinetree-shaped extracellular part (distal). The functional significance of these pore canals is discussed. It is concluded that their light scattering properties cause the wide visual fields of the photoreceptor cells measured electrophysiologically in the dorsal rim area, and that this is related to the way this eye region detects polarization in skylight.
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    URL: http://dx.doi.org/10.1007/BF00238646
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  • 15
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    The sensillum capitulum, an antennal hygro- and thermoreceptive sensillum of the cockroach, Periplaneta americana L. (1981)
    Springer
    Cell & tissue research 216 (1981), S. 525-543 
    Details
    ISSN: 1432-0878
    Keywords: Hygroreceptor ; Thermoreceptor ; Sensillum capitulum ; Cockroach ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sensillum capitulum, a hygro- and thermoreceptive sensillum of the cockroach Periplaneta americana L. is comprised of four receptor cells, one glial cell, two gland cells and four enveloping cells. Each receptor cell sends a single axon to the CNS, and has a single dendrite which extends distally. The perikarya of three receptor cells are enclosed by one of the enveloping cells (number one) and the fourth by a gland cell. The dendrites of all four receptor cells are enclosed by the same enveloping cell. The dendrites contain rootlets and many microtubules. The sensory cilia arise at the end of the dendrites at the level of the inner cavity, expand from the connecting cilium in a manner similar to those of the amphinematic scolopidia, and have numerous microtubules. The 1st enveloping cell contains scolopale rod-like structures. The sensory cilia are surrounded distally by a cuticular sheath formed within the 1st enveloping cell. One of the sensory cilia disappears distally, and the remaining ones enter the sensillum cone. Of these, one branches and the other two do not. The distal ends of the unbranched cilia are differentiated into tubular structures. The sensillum cone is comprised of an inner stem and a guard wall, neither of which is perforated. The outer cavity is enclosed by the 2nd, 3rd, and 4th enveloping cells, and distally in the antenna is closely apposed to the cuticular wall. This cavity contains lipid deposits. These structural features are discussed with regard to the mechanism of hygroreception in P. americana.
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    URL: http://dx.doi.org/10.1007/BF00238649
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  • 16
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    Stereological studies on the small intestinal epithelium of the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 11-21 
    Details
    ISSN: 1432-0878
    Keywords: Intestinal mucosa ; Small intestinal epithelium ; Ultrastructure ; Duodenum ; Jejunum ; Stereology ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative macroscopic, light-microscopic and electron-microscopic studies were performed on the small intestine of fasted and non-fasted adult, male Sprague-Dawley rats. In non-fasted rats the small intestine was longer than in fasted rats. Due to the presence of villi the surface area in the duodenum and the jejunum was enlarged about six times. The microvilli on the villous crests caused a surface enlargement by 13 times in the duodenum (value corrected for overestimation due to section thickness), and 19 times in the jejunum of the fasted rats. At the base of the villi these values were about 50% lower. It was calculated that, in the fasted rats, the total enlargement of the luminal surface area — due to villi and microvilli — was 63 times in the duodenum and 81 times in the jejunum (corrected for section thickness). Differences between the villous crest epithelium and the villous base epithelium were also found with regard to the mean cell height, and the volume densities of the absorptive cell nuclei, the mitochondria, and the paracellular channels.
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    URL: http://dx.doi.org/10.1007/BF00233821
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  • 17
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    Pre-fertilization ovule development inCapsella: ultrastructure and ultracytochemical localization of acid phosphatase in the meiocyte (1981)
    Springer
    Protoplasma 107 (1981), S. 27-45 
    Details
    ISSN: 1615-6102
    Keywords: Acid phosphatase ; Capsella ; Female meiocyte ; Ovule ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pre-meiotic and prophase I ovules ofCapsella bursa-pastoris (L.) Medic.(monosporic,Polygonum type of gametophyte development) were fixed routinely or incubated in a modified Gomori medium containing β-glycerophosphate as a substrate. Prior to the beginning of meiosis the potential meiocyte is ultrastructurally similar to the other cells of the nucellus and is distinguished only by its size and position. At the initiation of prophase I dramatic ultrastructural and ultracytochemical changes take place in the female meiocyte. These include the sudden appearance of cytoplasmic structures composed of single and multiple concentric cisternae, distinctive changes in plastids and mitochondria, and the blebbing of 0.3 μm double-membraned vesicles from the nuclear envelope. The concentric cisternae encapsulate portions of cytoplasm containing ribosomes, plastids, mitochondria, ER fragments and vesicles. Both single and multiple concentric cisternae localize high levels of acid phosphatase and function as autophagic vesicles (AVs) that sequester ribosomes and organelles for destruction during meiosis. Plastids stop dividing and become more spherical during prophase I. Some plastids localize acid phosphatase and many show continuities between the outer membrane and the plastid envelope and acid phosphatase-rich RER cisternae. Mitochondria appear as dense, contracted spheres or rods. Some mitochondria localize acid phosphatase but they do not show membrane confluencies with the ER. Some of the plastids and mitochondria that are segregated into the functional megaspore at meiosis II are destroyed but others apparantly survive meiosis and give rise to the plastid and mitochondrial populations of the young gametophyte (Schulz andJensen, unpublished). The lateral and end walls of the meiocyte show patches of intense aniline blue fluorescence and the chalazal end wall of the cell is perforated with large numbers of plasmodesmata.
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    URL: http://dx.doi.org/10.1007/BF01275605
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  • 18
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    Ultrastructure of the sperms ofPlumbago zeylanica (1981)
    Springer
    Protoplasma 107 (1981), S. 85-107 
    Details
    ISSN: 1615-6102
    Keywords: Male cytoplasmic inheritance ; Plumbago ; Pollen grain ; Pollen tube ; Sperm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Male gametes ofPlumbago zeylanica were examined in pollen grains and tubes using light and electron microscopy of chemically and physically fixed tissues, and Nomarski interference microscopy of isolated, living sperm cells. Male gametes are elongate, spindleshaped cells containing a nucleus, mitochondria, ER, ribosomes, vesicles, dictyosomes, probable microfilaments, and a variable number of plastids. In mature pollen grains ofP. zeylanica, the two sperm cells are directly linked; they share a transverse cell wall with plasmodesmata and are enclosed together by the inner vegetative cell plasma membrane. One of these two sperms is also associated with the vegetative nucleus as a consistent feature of pollen grain organization. The basis of this association appears to be a long, narrow projection of the sperm cell (averaging 〈 1 μm wide and about 30 μm long) which wraps around the periphery of the vegetative nucleus and occupies embayments of that nucleus. This association is maintained throughout pollen tube growth but becomes less extensive near the completion of tube growth and is severed following tube discharge. The consistent occurrence of the sperm-vegetative nucleus association in pollen grains, tubes and isolated pollen cytoplasm suggests that the two structures may be directly connected, but attempts to visualize this type of connection were unsuccessful. Possibly, the entwining nature and extent of complementary interfaces between vegetative nucleus and sperm may have a role in stabilizing their association. Functionally, the two sperms and vegetative nucleus appear to travel as a linked unit within the pollen tube, possibly increasing the effectiveness of gamete delivery and helping to ensure nearly simultaneous transmission of sperms into the receptive megagametophyte.
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    URL: http://dx.doi.org/10.1007/BF01275610
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    Occurrence of the suberized lamella in leaves of grasses of different photosynthetic types. I. In parenchymatous bundle sheaths and PCR (“Kranz”) sheaths (1981)
    Springer
    Protoplasma 109 (1981), S. 371-401 
    Details
    ISSN: 1615-6102
    Keywords: C4 Photosynthesis ; C4 Types ; Leaf blades ; Poaceae ; Suberized lamella ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaf blades of 42 grasses (Poaceae) have been examined ultrastructurally for the occurrence of a suberized lamella in walls of parenchymatous bundle sheaths and PCR (= “Kranz”) sheaths in both large and small vascular bundles. The sample includes species from a range of major grass taxa, and represents all photosynthetic types found in the grasses. Three grasses with unusual C4 leaf anatomy were also included:Alloteropsis semialata, Aristida biglandulosa, Arundinella nepalensis. The presence of a suberized lamella in PCR cell walls was perfectly correlated with photosynthetic type. All PEP-carboxykinase type and NADP-malic enzyme type C4 species examined possessed a suberized lamella in outer tangential and radial walls, but with variable presence in inner tangential walls. PCR cells of bothAlloteropsis semialata andArundinella nepalensis also possessed a suberized lamella. A lamella was totally absent from parenchymatous bundle sheath cells of the C3 species examined (5 spp.) and ofPanicum milioides, a C3-C4 intermediate. It was also absent from PCR cells of NAD-malic enzyme type C4 species (14 spp.) andAristida biglandulosa. The results are discussed in relation to the leakage of CO2 from PCR cells, and to differences between C4 types in δ13C values, chloroplast position in PCR cells, and other anatomical characteristics.
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    URL: http://dx.doi.org/10.1007/BF01287454
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    Ultrastructure of cell division and reproductive differentiation of male plants in theFlorideophyceae (Rhodophyta). Mitosis inDasya baillouviana (1981)
    Springer
    Protoplasma 106 (1981), S. 329-341 
    Details
    ISSN: 1615-6102
    Keywords: Dasya ; Mitosis ; Rhodophyta ; Spermatangia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitosis in the marine red algaDasya baillouviana (Ceramiales, Florideophyceae) was observed with the electron microscope. Most details of the process are quite similar to those observed in the other macroscopic red algae studied to date. However, some minor variations were noted. At late prophase a very small nuclear envelope protrusion (NEP) is formed at each division pole subjacent to the “nucleus associated organelle” known as the polar ring (PR) and 2–3 cisternae of perinuclear endoplasmic reticulum (PER) are commonly present during metaphase-anaphase. In contrast, in the other florideophycean algae where mitosis has been reported, a prominent NEP is present at late prophase (McDonald personal communication,Scott et al. 1980) and only a single cisterna of PER is observed. Additionally, during mid-late interphase and in mitotically-quiescent cells ofDasya, a single cisterna of smooth-surfaced ER is always juxtaposed with each PR. The possible significance of PER in theFlorideophyceae and other multinucleate organisms is discussed as well as the likely functions of spindle-associated smooth ER. It is suggested that ultrastructural features of mitosis should be useful as criteria to aid in the interpretation of the phylogeny of red algae.
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    URL: http://dx.doi.org/10.1007/BF01275563
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    Etude ultrastructurale de la spermatogènese chezTrichinella spiralis Owen 1835 (Nématode trichuroïde) (1981)
    Springer
    Parasitology research 64 (1981), S. 207-215 
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    ISSN: 1432-1955
    Keywords: Ultrastructure ; Spermatogenesis ; Nematoda ; Trichinella spiralis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude ultrastructurale de la spermatogénèse chezT. spiralis a permis de retrouver chez cette espèce les caractères morphologiques observés dans la lignée mâle chez la plupart des Nématodes, c'est-à-dire absence de flagelle chez le spermatozoïde, absence de reconstitution de l'enveloppe nucléaire après divisions méiotiques, structure atypique du centriole. Elle a permis de situer le spermatozoïde par rapport aux classifications antérieurement proposées.
    Notes: Abstract The ultrastructural study of spermatogenesis inT. spiralis demonstrated the main characteristics of the male germ cells in the class Nematoda, i.e. lack of flagella, lack of reconstitution of the nuclear envelope after the meiotic divisions, and atypical structure of the centriole. The spermatozoon ofT. spiralis was compared with previous classifications of the Nematoda spermatozoa.
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    URL: http://dx.doi.org/10.1007/BF00930498
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    The ultrastructure of the epidermis of the redia ofParorchis acanthus nicoll (Digenea; Philophthalmidae) (1981)
    Springer
    Parasitology research 65 (1981), S. 19-30 
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    ISSN: 1432-1955
    Keywords: Parorchis acanthus ; Redia ; Ultrastructure ; Epidermis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Regional and age differences in the epidermis of the redia ofP. acanthus have been studied by transmission electron microscopy. The depth of the outer cytoplasmic epidermis increases by four times from stage I to stage III and the microvilli double their length and branch by stage II. Electron-dense and electron-lucent membrane bound bodies are present in all stages, the latter being released onto the surface as vesicles. Multivesicular bodies appear in stage III. All are formed in one type of secretory epidermal cell body. Anterior and posterior concentric folds, of thickened outer cytoplasmic epidermis only, increase the surface area and also the diameter of the redia on contraction. In stages I and II the apical regions of the ventro-lateral processes and birth papilla, and the lattice pattern on the posterior papilla, each consisting of thickened outer cytoplasmic epidermis only, may provide rigidity and support during migration. The uniciliate sensory receptors appear to be mechanoreceptors.
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    URL: http://dx.doi.org/10.1007/BF00926550
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    The glomerulus of a stenohaline fresh-water teleost, Carassius auratus gibelio, adapted to saline water (1981)
    Springer
    Cell & tissue research 220 (1981), S. 73-85 
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    ISSN: 1432-0878
    Keywords: Glomerulus ; Stenohaline fresh-water teleost ; Salt-water adaptation ; Kidney ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prussian carp, Carassius auratus gibelio, were maintained in aquaria with a salinity of 15‰ for 3 months. More than 90% of the glomeruli disappeared from the tissue as a result of the adaptation to saline water. Kidney tissue was excised and prepared for electron microscopy after perfusion fixation in situ. The fine structure of the renal corpuscle was compared with the normal ultrastructure of glomeruli of control fish from fresh-water aquaria. The main alterations include retraction of the endothelium from the basement membrane, widening of the subendothelial region, folding of the thickened basement membrane and epithelial layer, and the dislocation of slit diaphragms. The findings are discussed in relation to developmental stages of mammalian glomeruli and glomeruli from tissue cultures. The structural changes of the rudimentary glomeruli of the carp kept in 15‰ salt water differ from those observed in euryhaline fish from sea water.
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    URL: http://dx.doi.org/10.1007/BF00209967
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    Developmental stages and localization of peroxidatic activity in the leucocytes of three teleost species (Cyprinus carpio L.; Tinca tinca L.; Salmo gairdneri Richardson) (1981)
    Springer
    Cell & tissue research 220 (1981), S. 163-180 
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    ISSN: 1432-0878
    Keywords: Leucocytes ; PO-reactivity ; Teleosts (Cyprinus carpio L., Tincatinca L., Salmo gairdneri R.) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of peroxidase (PO) in the leucocytes of three teleosts (Cyprinus carpio L., Tinca tinca L., Salmo gairdneri R.) has been investigated using the 3,3′-diaminobenzidine method. In the heterophilic granulocytes the granules show a species specific structure and are PO-positive at pH 7.6. They can be traced back to small granules arising near the Golgi apparatus (GA) in the promyelocyte. They coalesce to form larger granules and gradually change into the mature type. Myelocytes contain small unreactive granules, and these represent a second granule population. Eosinophils contain one PO-positive granule type (at pH 9), and these granules show a varying density during cell maturation. Basophils are present only in the Cyprinid species, and contain unreactive granules originating from precursors displaying a weakly positive reaction at pH 7.6. The active secretory organelles (RER, GA) are PO-negative, except for a weakly positive reaction in the flocculent matrix of the inner G-cisternae. In promonocytes and monocytes the granules are unreactive, but in the macrophages PO-positive staining occurs in a few small to medium sized granules, and in large vacuoles. At least some of these latter are apparently derived from phagolysosomes containing digested erythrocytes. Thrombocytes and lymphocytes are unreactive. The successive development of PO-positive and negative granule populations in the heterophils, and the PO-reactivity of eosinophils and basophils, show some similarities to the corresponding cells in higher vertebrates, but an analogous PO-positive (“azurophil”) granule type in monocytes seems to be absent.
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    Ultrastructural studies on the nucleoli of the follicle cells in the Lizards Acanthodactylus scutellatus hardyi and Eremias brevirostris (1981)
    Springer
    Cell & tissue research 214 (1981), S. 169-180 
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    ISSN: 1432-0878
    Keywords: Nucleolus ; Pyriform cells ; Intermediate cells ; Lizards ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the nuclei in the ovarian follicular cells has been examined in the lizards Acanthodacylus scutellatus hardyi, and Eremias brevirostris. During certain growth stages, the nuclei of the intermediate and the pyriform cells become large and conspicuous, and usually contain numerous morphologically variable nucleoli. The latter may be nucleolonemal, compact, ring-shaped, “filamentous”, “fine-filamentous”, “amorphous” or “course-granular” in type, and the number and type in each nucleus seems to be related to the developmental stage. The type of nucleolus may indicate different phases of activity in the nucleus and may also suggest an association with the production of different types of RNA.
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    URL: http://dx.doi.org/10.1007/BF00235154
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    Identification and morphometric evaluation of the synapses of optic nerve afferents in the optic tectum of the axolotl (Ambystoma mexicanum) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 593-611 
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    ISSN: 1432-0878
    Keywords: Synapses ; Optic afferents ; Optic tectum ; Axolotl ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The terminals of retinal afferents in the tectum of the axolotl have been identified ultrastructurally using techniques of horseradish peroxidase-filling and degeneration. The mitochondria in filled structures show a characteristic electron-lucent matrix. After both eyes have been removed, terminals with light mitochondria disappear from the area known to receive an optic input. In this area the presence of light mitochondria is almost always diagnostic of the retinal origin of a bouton. The synapses are similar to those assumed to be of retinal origin in other vertebrates. Detailed morphometric analysis has been carried out on identified optic synapses in the optic tectum of the axolotl.
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    The ultrastructure of the innervation of the intestinal wall in the teleosts Myoxocephalus scorpius and Pleuronectes platessa (1981)
    Springer
    Cell & tissue research 214 (1981), S. 651-658 
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    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Ultrastructure ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the intestinal wall in the teleosts Myoxocephalus and Pleuronectes was examined electron microscopically. Two classes of axons can be identified. The first, which is in the majority, contains numerous 50–150 nm granular vesicles as well as some 40–50 nm agranular vesicles while the second contains predominantly the 40–50 nm agranular vesicles. Chromate/dichromate staining methods suggest that the first type is aminergic. Both types lie in close association with the perikarya of intrinsic myenteric neurons but only axons containing predominantly agranular vesicles have synaptic membrane specialisations. No axon bundles pass into the longitudinal muscle layer in Myoxocephalus gut and though some do in Pleuronectes, they do not closely approach the smooth muscle cells. Axons containing large granular vesicles lie in intimate contact with the myocytes of the circular muscle layer. Both axon types pass through the submucosa to form a plexus underneath the mucosal epithelium. Varicosities containing agranular or granular vesicles are separated from the epithelial cells by a gap of about 200 nm in which lies a basal lamina.
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    URL: http://dx.doi.org/10.1007/BF00233504
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    Nerves containing substance P, vasoactive intestinal polypeptide, enkephalin or somatostatin in the guinea-pig taenia coli (1981)
    Springer
    Cell & tissue research 215 (1981), S. 21-39 
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    ISSN: 1432-0878
    Keywords: Peptidergic nerves ; Guinea-pig taenia coli ; Substance P ; Vasoactive intestinal peptide ; Somatostatin ; Enkephalin ; Ultrastructure ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The guinea-pig taenia coli is rich in peptide-containing nerves. Nerve fibres containing substance P (SP), vasoactive intestinal peptide (VIP), or enkephalin, were numerous in the smooth muscle while somatostatin fibres were very few. Nerve fibres displaying SP or VIP immunoreactivity were numerous in the myenteric plexus. Enkephalin nerve fibres were fairly numerous in the plexus while somatostatin nerve fibres were sparse. Nerve cell bodies containing immunoreactive SP or VIP were regularly seen in the plexus. Delicate varicose elements of the different types of nerve fibres were found to ramify around nerve cell bodies in a manner suggestive of innervation. In the electron microscope the various peptide-storing nerve fibres (i.e., elements containing SP, VIP or enkephalin) were found to contain a varying number of fairly large, electron-opaque vesicles in the varicose swellings. These vesicles represent the storage site of the neuropeptides. The isolated taenia coli responded to electrical nerve stimulation with a contraction. After cholinergic and adrenergic blockade the contractile response was replaced by a relaxation followed by a contraction upon cessation of stimulation. SP contracted the taenia while VIP caused a relaxation. The enkephalins raised the resting tension slightly while somatostatin had no effect. These observations are compatible with a role for SP as an excitatory neurotransmitter and for VIP as an inhibitory one, and with the view that both SP neurones and VIP neurones act as motor neurones. In preparations contracted by SP the electrically induced contractions were reduced in amplitude while the electrically induced relaxations seen after adrenergic and cholinergic blockade were enhanced in amplitude. In preparations relaxed by VIP there was an increased contractile response to electrical stimulation, while in the atropine + guanethidine-treated preparation the electrically induce relaxations were reduced in amplitude. The enkephalins reduced the contractile response to electrical stimulation, while somatostatin induced a very small reduction in the amplitude of such responses. These observations suggest that SP neurones and VIP neurones may play additional roles as interneurones. Somatostatin neurones probably act as interneurones. Enkephalin-containing fibres may serve to modify the release of transmitter from other nerves in the smooth muscle, perhaps through axo-axonal arrangements. Alternatively, the enkephalin nerve fibres in the smooth muscle are afferent elements involved in mediating sensory impulses to the myenteric plexus.
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    Hepatocyte differentiation during early fetal development in the rat (1981)
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    Cell & tissue research 215 (1981), S. 133-142 
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    ISSN: 1432-0878
    Keywords: Rat fetus ; Hepatocyte differentiation ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat hepatocyte differentiation between day 12 and 19 of fetal life was studied by electron microscopy. The cytoplasmic structures involved in synthetic and secretory function, i.e., rough endoplasmic reticulum and Golgi apparatus, appear to be the first to differentiate, and their development is probably related to the secretion of different kinds of plasma proteins. The cytoplasmic organelles involved in other hepatic functions develop later: lysosomes from day 15, peroxysomes, glycogen rosettes and smooth endoplasmic reticulum still later. However, the morphological differentiation of bile canaliculi begins from day 12.
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    The hypothalamic magnocellular system in the domestic fowl (1981)
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    Cell & tissue research 215 (1981), S. 113-131 
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    ISSN: 1432-0878
    Keywords: Hypothalamus ; Neurosecretory cells ; Domestic fowl ; Golgi study ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the rostral hypothalamus of the domestic fowl, the magnocellular neurosecretory nuclei show a peculiar differentiation. Golgi studies of the supraoptic and paraventricular nuclei of the fowl reveal at least two major cell types: 1) large multipolar neurons, and 2) small interneurons. Golgi impregnations provide a detailed cytoarchitectural picture of the large-sized cells; the latter may well correspond to the neurosecretory cells demonstrated in the same regions by selective staining, and immunocytochemical and electron microscopical techniques. Electron microscopically, neuronal perikarya are observed to contain variable amounts of neurosecretory granules (100–200 nm in diameter; mean diameter of 160 nm) scattered throughout the cytoplasm. The diameters of these granules do not differ statistically in the two principal nuclear areas examined. The perikarya of these neurons display only a few axosomatic synapses containing electron-lucent and dense-cored vesicles (70–90 nm in diameter). Numerous nerve terminals of this type also end on the dendritic ramifications in the surrounding neuropil.
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    Input and output synapses on identified motor neurones of a locust revealed by the intracellular injection of horseradish peroxidase (1981)
    Springer
    Cell & tissue research 215 (1981), S. 325-332 
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    ISSN: 1432-0878
    Keywords: Horseradish peroxidase ; Locust ; Motor neurone ; Synapse ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Physiologically characterised motor neurones in the thoracic ganglia of the locust were injected with horseradish peroxidase in order that the spatial relationship between their input and output synapses could be observed with the electron microscope. A modification in the development procedure for the peroxidase ensured that the internal fine structure of the stained neurones was not obscured by the diaminobenzidine reaction product. Input and output synapses may occur within 1 μm of each other on the neuropilar processes of the motor neurones. This supports physiological evidence that motor neurones may be involved in local circuit interactions within the thoracic ganglia.
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    Differentiation and transdifferentiation of adrenal chromaffin cells of the guinea-pig (1981)
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    Cell & tissue research 215 (1981), S. 341-367 
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    ISSN: 1432-0878
    Keywords: Adrenal chromaffin cells ; Plasticity ; Eye chamber transplants ; Ultrastructure ; Catecholamine biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Autografts of adrenal chromaffin cells from adult guinea pigs to the anterior chamber of the eye were studied electron microscopically and both histo-and biochemically 4, 8 and 12 weeks after transplantation. Transplanted chromaffin cells resembled in many respects their in-situcounterparts: they stored varying amounts of granular vesicles, which were reduced in diameter, but displayed mostly cores of low or medium electron densities suggesting predominant storage of a secondary amine. Concomitant biochemical determinations of catecholamines (CA) and phenylethanolamine N-methyltransferase (PNMT) activity revealed a distinct reduction of total CA and PNMT activity, but no change in the proportion of adrenaline (A) to noradrenaline (NA) after 4 weeks. However, an increase of NA and almost equal amounts of A and NA were found after 8 weeks. CA-histofluorescence and electron microscopy revealed that axon-like processes with varicosities extend from chromaffin cells and contain the large “chromaffin” vesicles (100–200 nm in diameter) in addition to small clear and dense-cored vesicles (40–80 nm in diameter). Processes of chromaffin cells grew in all directions over the host iris and were also found in close proximity to smooth muscle cells the sympathetic nerve supply of which had been cut by removing the superior cervical ganglion. Administration of 5-and 6-hydroxydopamine (OHDA) resulted in characteristic labeling and ultramorphological changes in axons, but caused alterations in chromaffin cell bodies only 8 weeks after transplantation. Transplanted chromaffin cells became reinnervated by nerve fibres that are considered to be cholinergic fibres derived from the ciliary ganglion. Transplanted chromaffin cells also exhibited synapse-like contacts with each other. The present study shows that chromaffin cells from adult guinea pigs transplanted to the anterior chamber of the eye retain a large number of differentiated properties. Formation of axon-like processes by these cells indicates that the anterior chamber of the eye favours transdifferentiation, as does tissue culture (Unsicker et al. 1978a), eliciting a cell type that displays features of both a sympathetic neurone and a SIF-cell.
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    Effect of disulfiram on the ultrastructure of the peptidergic and aminergic cells in the pars intercerebralis of Galleria mellonella (Lepidoptera) (1981)
    Springer
    Cell & tissue research 215 (1981), S. 417-424 
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    ISSN: 1432-0878
    Keywords: Galleria ; Neurosecretory cells ; Pars intercerebralis ; Disulfiram ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Injection of disulfiram, a specific inhibitor of noradrenaline synthesis, evokes changes in two different types of neurons in the brain of Galleria mellonella: neurones containing dense-core vesicles (60–80 nm) and peptidergic cells containing 180–200 nm neurosecretory granules. The lowering of the electron density of the dense-core vesicles of 60–80 nm seems to be directly connected with disulfiram administration, while the decrease of the amount of neurosecretory material in the neurosecretory cells of type I seems to be a secondary effect of the drug injection. The participation of noradrenaline in the regulation of the secretory activity of type I peptidergic neurosecretory cells of the pars intercerebralis is postulated.
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    Ultrastructural studies on oogenesis in symphyla (1981)
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    Cell & tissue research 215 (1981), S. 431-436 
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    ISSN: 1432-0878
    Keywords: Oogenesis ; Cortical granules ; Chorion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the oocytes of Hanseniella nivea, cortical granules are formed in the peripheral ooplasm during late stages of oogenesis. Single Golgi elements are involved in the process. Concurrent with the formation of cortical granules is the appearance of a chorion on the oocyte surface. Precursors of this envelope are most likely synthesized by follicle cells.
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    Effects of pimozide on the ultrastructure of the pars intermedia in the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 397-403 
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    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; MSH-cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars intermedia of the rat. The animals received 100 μg/100 g pimozide daily for 2, 5, 10, 15, and 20 days. Pimozide induces ultrastructural changes after 5 days of treatment. About 50% of the MSH-cells display characteristics of stimulation. Their cytoplasm is partially or totally depleted of secretory granules. The rough endoplasmic reticulum displays a network of interconnecting cisternae and ribbon-like structures. The well-developed Golgi complexes exhibit numerous dilatations of their cisternae, which contain electron-dense material. The nerve endings are not altered. Twenty days after treatment, the above-described changes have not decreased in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in some MSH-cells, most probably the elements underlying an inhibitory dopaminergic control.
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    Ultrastructure of spermiogenesis in Liza aurata Risso, 1810 (Teleostei, Mugilidae) (1981)
    Springer
    Cell & tissue research 217 (1981), S. 415-424 
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    ISSN: 1432-0878
    Keywords: Secondary spermatocytes ; Spermatids ; Spermatozoa ; Marine teleost ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sequential cytological events in late spermatogenesis of Liza aurata were studied from the stage secondary spermatocytes to that of mature spermatozoa. Spermiogenesis involves preparatory morphological events followed by conspicuous modifications such as intracellular movements (diplosome and mitochondrion migration, spermatid lengthening, nuclear rotation) and structural changes (dense chromatin granules, increase in size of mitochondria, loss of cytoplasm). Mature spermatozoa, with a round nucleus and a pseudo-midpiece are of a primitive type, even compared with spermatozoa of other teleosts.
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    Ultrastructural study of the postembryonic development of the neural lamella of Galleria mellonella L. (Lepidoptera) (1981)
    Springer
    Cell & tissue research 217 (1981), S. 425-433 
    Details
    ISSN: 1432-0878
    Keywords: Lepidoptera ; Neural lamella ; Postembryonic development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neural lamella encapsulating the brain of the wax moth Galleria mellonella develops from a very thin (80–120 nm) layer in the first larval instar, resembling the basal lamina, to a thick (1–4 μm) sheath composed of two zones in the seventh (last) instar. After its breakdown at the time of larval-pupal ecdysis the neural lamella is reconstructed in the pupa, 2–3 days before pupaladult ecdysis. The cells of the perineurium seem to be responsible for the formation of the neural lamella, both in the larva and pupa, even though its ultrastructure differs at these stages.
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    URL: http://dx.doi.org/10.1007/BF00233592
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    Isolation and primary culture of adult human hepatocytes (1981)
    Springer
    Cell & tissue research 218 (1981), S. 13-21 
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    ISSN: 1432-0878
    Keywords: Human ; Isolated hepatocytes ; Primary culture ; Albumin synthesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Biopsy tissue of adult human liver was gently dissociated with collagenase followed by Dispase. By repeated low g centrifugation, a large number of almost pure, viable hepatocytes was obtained. This is the first report of a successful procedure for obtaining adult human hepatocytes for study in tissue culture. The isolated cells have the typical morphology of liver parenchyma, and these characteristics persist throughout the period of culturing. Evidence of their function is indicated by albumin synthesis. This procedure is now being used to study human hepatocyte functions in vitro and the effects of a variety of agents including carcinogens and viruses.
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    URL: http://dx.doi.org/10.1007/BF00210087
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    Ultrastructure of the rat thymus: The micro-environment of T-lymphocyte maturation (1981)
    Springer
    Cell & tissue research 218 (1981), S. 279-292 
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    ISSN: 1432-0878
    Keywords: Thymus micro-environment (rat) ; Epithelial cells ; Macrophages ; Interdigitating cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the micro-environment of the fully functional rat thymus was studied. The thymus consists of two discrete compartments, viz., an epithelial and a mesenchymal compartment. Thymus fibroblasts/fibrocytes, mast cells and granulocytes, are restricted to the mesenchymal compartment. The thymocyte maturation process seems to occur in the epithelial compartment in a network of reticular epithelial cells. The cortex is finely meshed and filled with proliferating thymocytes and some scattered macrophages. Moreover, in the medulla vacuolated epithelial cells form part of a loosely meshed reticulum which is filled with thymocytes and interdigitating cells (IDCs). IDCs frequently contain Birbeck granules and appear to be phagocytic. Together with macrophages, they probably enter the thymus, predominantly in the cortico-medullary region, and cross the separating wall between the two compartments. Some functional aspects of the non-lymphoid cells and in particular the IDCs, which form the micro-environment of the thymus, are discussed with respect to T-cell development.
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    URL: http://dx.doi.org/10.1007/BF00210344
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    Glycoprotein gonadotropin in the plasma and its cellular origin in the adenohypophysis of sham-operated and ovariectomized rainbow trout, salmo gairdneri (1981)
    Springer
    Cell & tissue research 218 (1981), S. 439-448 
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    ISSN: 1432-0878
    Keywords: Pituitary salmonids ; GTH-cells ; Ultrastructure ; Ovariectomy ; Radioimmunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Among the cells of the pituitary generally believed to produce glycoprotein gonadotropin (GTH) five forms were distinguished, based on the amount and the diameter of granules and globules and the appearance of the rough endoplasmic reticulum. In sham-operated trout so-called “globular” cells predominated, whereas after ovariectomy these were replaced by so-called “cisternal” cells, suggesting that both belong to one GTH-cell type. In addition, ovariectomy caused a strong increase in plasma GTH-levels. This indicates that the transition from globular to cisternal cells is accompanied by extrusion of GTH, and thus points to a storage of GTH in the granules and globules. It is argued that one of the five forms has the morphological characteristics of thyrotropic cells and may not produce glycoprotein GTH.
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  • 41
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    Ultrastructure of muscle fibres in head and axial muscles of the perch (Perca fluviatilis L.) (1981)
    Springer
    Cell & tissue research 219 (1981), S. 111-131 
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    ISSN: 1432-0878
    Keywords: Fish ; muscle fibre types ; Ultrastructure ; Morphometry ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary White, pink, red and deep red fibres, selected from a head muscle and from axial muscles of the perch, show significant differences in actin filament length, Z line thickness, Z line lattice space, myofibril girth, the percentages volume occupied by T system and terminal cisternae of the SR, and in the degree of T system SR contact per sarcomere. In both muscles the degree of T system SR contact decreases in the order: white, pink, red, deep red, which suggests a decrease of contraction velocity in the same order. The position of the T system (at the Z line or at the AI junction) is related to the actin filament length. The actin filaments in the red fibres are appreciably longer than in the white, which suggests that the sarcomeres of the red fibres have a broader length-tension curve. The Z line thickness is positively correlated with the actin filament length and, in the white and the red fibres, negatively with the degree of sarcomere shortening. Thicker Z lines are suggested to allow greater sarcomere sizes (length or girth). The percentage volume occupied by mitochondria varies independently of the extent of membrane systems. The ultrastructural characteristics of the fibre types are in agreement with the functional roles as reported in literature.
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    URL: http://dx.doi.org/10.1007/BF00210022
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    Ultrastructure of the pineal organ of the killifish, Fundulus heteroclitus, with special reference to the secretory function (1981)
    Springer
    Cell & tissue research 219 (1981), S. 355-369 
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    ISSN: 1432-0878
    Keywords: Pineal organ ; Secretory function ; Photosensory function ; Ultrastructure ; Killifish, Fundulus heteroclitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal organ of the killifish, Fundulus heteroclitus, was investigated by electron microscopy under experimental conditions; its general and characteristic features are discussed with respect to the photosensory and secretory function. The strongly convoluted pineal epithelium is usually composed of photoreceptor, ganglion and supporting cells. In addition to the well-differentiated photosensory apparatus, the photoreceptor cell contains presumably immature dense-cored vesicles (140–220 nm in diameter) associated with a well-developed granular endoplasmic reticulum in the perinuclear region and the basal process. These dense-cored vesicles appear rather prominent in fish subjected to darkness. The ganglion cell shows the typical features of a nerve cell; granular endoplasmic reticulum, polysomes, mitochondria and Golgi apparatus are scattered in the electron-lucent cytoplasm around the spherical or oval nucleus. The dendrites of these cells divide into smaller branches and form many sensory synapses with the photoreceptor basal processes. Lipid droplets appear exclusively in the supporting cell, which also contains well-developed granular endoplasmic reticulum and Golgi apparatus. Cytoplasmic protrusions filled with compact dense-cored vesicles (90–220 nm in diameter) are found in dark-adapted fish. The origin of these cytoplasmic protrusions, however, remains unresolved. Thus, the pineal organ of the killifish contains two types of dense-cored vesicles which appear predominantly in darkness. The ultrastructural results suggest that the pineal organ of fish functions not only as a photoreceptor but also as a secretory organ.
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    URL: http://dx.doi.org/10.1007/BF00210154
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    The fine structure of the neural lobe of the mouse after transplantation under the kidney capsule (1981)
    Springer
    Cell & tissue research 219 (1981), S. 417-423 
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    ISSN: 1432-0878
    Keywords: Neurohypophysis (Mouse) ; Transplantation ; Pituicytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurohypophysis of donor mice was implanted under the renal capsule of the recipients. The pituicytes survived while the neurosecretory axons disappeared. The ultrastructure of the glial cells was observed seven and nine weeks after transplantation. There were no signs of phagocytotic activity although remnants of axons were still present at seven weeks. The numerous processes of the pituicytes form a network with intercellular spaces wide in younger and narrower in older implants. The cells are connected by desmosomes and gap junctions. Pituicytes as well as blood vessels preserve their organotypic appearance. The transplant thus represents an experimental model for investigations on pituicytes in vivo in the absence of neurosecretory axons.
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    URL: http://dx.doi.org/10.1007/BF00210159
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    Development of the bovine acrosome (1981)
    Springer
    Cell & tissue research 219 (1981), S. 511-524 
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    ISSN: 1432-0878
    Keywords: Acrosome, bovine ; Acrosomal development ; Acrosomal glycoproteins ; Ultrastructure ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study the development of the bovine acrosome was investigated using conventional electron-microscopical techniques as well as the phosphotungstic-acid (PTA) technique (Rambourg 1967) including enzymatic digestion experiments. As in other species and in accordance with previous light-microscopical studies (Clermont and Leblond 1955) four phases of acrosomal differentiation can be discerned: the Golgi-phase, cap-phase, acrosome-phase, and maturation-phase. In the bull no internal pattern of the acrosomal content can be observed, either with conventional uranyl acetate-lead citrate staining or with the PTA-techniques. Our results support the observation in other species (Fawcett et al. 1971) that no intrinsic polymerization or crystallization process of the acrosomal content is responsible for acrosomal shaping. Some of our results suggest the influence of external forces on acrosomal development in the bull. During the cap-phase and the acrosome-phase accumulations of smooth endoplasmic reticulum and a layer of fine filaments can be observed in the Sertoli-cell cytoplasm, immediately adjacent to the developing acrosome. A temporary influence of these structures on acrosomal development seems possible. The PTA-positive staining of the developing bovine acrosome is probably due to the presence of acrosomal glycoproteins; however, our results do not exclude the possibility that molecules other than glycoproteins contribute to the positive PTA-staining of the developing acrosome.
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    Electron-microscopic studies on the relationship between the frequency of parathyroid storage granules and serum calcium levels in the rat (1981)
    Springer
    Cell & tissue research 219 (1981), S. 457-467 
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    ISSN: 1432-0878
    Keywords: Parathyroid (Rat) ; Storage granules ; Serum calcium level ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the rat parathyroid, the mean number of storage granules (NSG) per chief cell has been electron-microscopically studied and correlated with the mean serum calcium level (SCL). In animals given 4% CaCl2 plus vitamin D2 for 3 days, SCL is significantly elevated and NSG is increased. When these animals are injected with 2% EDTA, SCL is lowered to 8 mg/dl, but NSG is not affected; in those injected with 4% EDTA, however, SCL declines to a minimum (5.8 mg/dl) after 30 min, and NSG is also decreased. Control SCL are 8.9 mg/dl. These results indicate that storage granules may not be released until SCL is depressed to a certain level. In rats 3 weeks after castration, the chief cells show hyperplastic changes and SCL is at a low concentration (8.0 mg/dl). NSG, however, remains almost within control limits. Castrated animals injected with 4% EDTA show a hypocalcemia and a decrease in NSG, but NSG gradually recovers over a period of 6h. These data suggest that storage granules can be produced even under lower calcium concentrations. It is concluded that storage granules may be constantly produced and stored, and are released only as an emergency supply of hormone.
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    Ultrastructural study of the sinus gland of the crab, Cardisoma carnifex (1981)
    Springer
    Cell & tissue research 220 (1981), S. 293-312 
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    ISSN: 1432-0878
    Keywords: Neurosecretion ; Sinus gland ; Ultrastructure ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sinus gland of Cardisoma carnifex was examined by light and transmission electron microscopy. This neurohemal organ is composed primarily of enlarged, branching axon terminals with numerous finger-like projections, which act as storage and release sites for neurohormones that are assumed to be contained in membrane-bound, electron-dense neurosecretory granules. Also present in the sinus gland are glial cells with cytoplasmic processes which form elaborate wrappings around neurosecretory terminals, and an acellular fibrillar lining of the branching blood sinus. Six types of neurosecretory terminals are identified on the basis of granule size, granule density, and density of the axoplasmic matrix. Images supporting the hypothesis of release of neurosecretory material by exocytosis from terminals abutting the blood sinus lining are found. Large multilamellate bodies appear in terminals depleted of neurosecretory granules and may be involved in the recycling of granule membrane.
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    Morphologic development of neonatal rat pinealocytes in monolayer culture (1981)
    Springer
    Cell & tissue research 220 (1981), S. 337-347 
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    ISSN: 1432-0878
    Keywords: Pineal ; Monolayer culture ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological development of pinealocytes maintained in monolayer culture, without the neural and humoral effects present in the developing rat has been studied and compared with the development that occurs in vivo. Pinealocytes in 5 day cultures contained organelles that were similar to those present in the pineals of intact 5 day old rats. However, light and dark cells were not noted in culture, and the cultured cells did not have the dense granules noted in vivo. As pinealocytes developed in culture, cytoplasmic processes increased in length and number. By 21 days of culture age, synaptic ribbons were found to have decreased in number, the difference between light cell and dark cell cytoplasm had become more prominent, and dense-cored vesicles had become more numerous, just as in the developing gland in vivo. These results suggest that the complex neural and humoral factors impinging upon the developing neonatal pineal in the intact animal may not be necessary for some aspects of its ultrastructural differentiation.
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    Ultrastructural study of Kupffer cells in teleost liver under normal and experimental conditions (1981)
    Springer
    Cell & tissue research 220 (1981), S. 387-391 
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    ISSN: 1432-0878
    Keywords: Kupffer cells ; Liver ; Sinusoids ; Teleost ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The Kupffer cells in the liver of the teleost fish, Pimelodus maculatus, are attached by desmosomes to the endothelial cells lining the sinusoids. These provide a strong attachment allowing them to resist the passage of blood. Following perfusion with India ink, both endothelial and Kupffer cells ingest India ink particles by pinocytosis and micropinocytosis. It is suggested that both cell types may represent two different functional states of the same cell.
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    Fine structural study of the statocysts in the veliger larva of the nudibranch, Rostanga pulchra (1981)
    Springer
    Cell & tissue research 214 (1981), S. 67-80 
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    ISSN: 1432-0878
    Keywords: Statocyst ; Larva ; Nudibranch ; Sensory cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The two statocysts of the veliger larva of Rostanga pulchra are positioned within the base of the foot. They are spherical, fluid-filled capsule that contain a large, calcareous statolith and several smaller concretions. The epithelium of the statocyst is composed of 10 ciliated sensory cells (hair cells) and 11 accessory cells. The latter group stains darkly and includes 2 microvillous cells, 7 supporting cells, and 2 glial cells. The hair cells stain lightly and each gives rise to an axon; two types can be distinguished. The first type, in which a minimum of 3 cilia are randomly positioned on the apical cell membrane, is restricted to the upper portion of the statocyst. The second type, in which 9 to 11 cilia are arranged in a slightly curved row, is found exclusively around the base of the statocyst. Each statocyst is connected dorso-laterally to the ipsilateral cerebral ganglion by a short static nerve, formed by axons arising from the hair cells. Ganglionic neurons synapse with these axons as the static nerve enters the cerebral ganglion. The lumen of the statocyst is continuous with a blind constricted canal located beneath the static nerve. A diagram showing the structure of the statocyst and its association with the nervous system is presented. Possible functions of the statocyst in relation to larval behavior are discussed.
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    Control of the pars intermedia of the lizard, Anolis carolinensis (1981)
    Springer
    Cell & tissue research 214 (1981), S. 1-22 
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    ISSN: 1432-0878
    Keywords: Neuro-intermediate lobe ; Anolis carolinensis ; Horseradish peroxidase ; Ultrastructure ; Extracellular space ; Ependymal cells ; Stellat cells ; Secretory cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of the tracer substance horseradish peroxidase (HRP, Mw 40,000) in the neuro-intermediate lobe of the lizard, Anolis carolinensis, was studied at various time intervals (13 min to 24 h) after vascular injection. HRP rapidly entered the extracellular lumen of the neural lobe, but did not penetrate into the third ventricle. The tracer was found in micropinocytotic vesicles (MPVs) of ependymal cells within 13 min after injection. The number of cellular inclusions containing HRP increased during the period of observation (24 h). The tracer was sparsely taken up by aminergic and peptidergic nerve terminals of the external layer. After transection of the hypophysial stalk, numerous dense, labelled droplets were found in the peptidergic terminals, and the number of labelled inclusions in ependymal cells increased. MPVs were frequently found in extensions of stellate cells of the intermediate lobe, and endocytotic vacuoles (EVs) developed especially in the perikaryon. HRP was also found in large cisternae of the secretory cells, appearing predominantly towards the perivascular septum (PVS). These cisternae were found to communicate with the extracellular lumen, probably representing a system of the extracellular space extending into the secretory cell. After transection of the hypophysial stalk, there was an increase in the number of small EVs in secretory cells of the intermediate lobe. The results are discussed in terms of MSH-release regulation and possible participation of the extracellular lumen, glial and stellate cells in the transport of regulating factors and secretory material.
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    Fine structure of the cirri and a possible mechanism for their motility in stalkless crinoids (Echinodermata) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 207-217 
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    ISSN: 1432-0878
    Keywords: Echinoderm ; Filament bundles ; Motility ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Crinoid cirri are jointed appendages that can slowly bend and straighten. The structures causing each cirrus to move have not been identified unequivocally by light microscopy; therefore, we examined them by electron microscopy. No muscle cells were found, but a probable contractile apparatus was demonstrated in the cytoplasm of epithelial cells lining the oral and aboral coeloms running the length of the cirrus. The presumed contractile apparatus is a bundle of 5 nm filaments oriented parallel to each other and to the long axis of the appendage. We have proposed that contractile shortening of the coelomic epithelia bends the cirrus in an aboral direction, since the fulcral articulations of the skeletal ossicles are oral to the contractile tissue; this active bending is presumably opposed by an elasticity of the oral ligaments, which seem to straighten the cirrus. It is possible that ligaments of the cirrus may undergo neurosecretion-mediated changes in consistency that could lock the appendage into a rigid state; however, active contraction by the ligaments appears unlikely.
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    Seasonal changes in ultrastructure of brown adipose tissue in the common shrew (Sorex araneus L.) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 623-632 
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    ISSN: 1432-0878
    Keywords: Brown adipose tissue ; Ultrastructure ; Seasonal changes ; Shrew (Sorex)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Seasonal changes have been detected in the ultrastructure of brown adipose tissue (BAT) of the common shrew, Sorex araneus (a true non-hibernator) living under natural conditions and collected at the time when the most representative growth phase of the animal for the given season could be expected. In summer and autumn, BAT is characterized by the presence of large, regular, spherical lipid droplets and mitochondria closely adhering to one another. During winter, mitochondria possess densely packed cristae and are dispersed in the cytoplasm, sometimes invaginating into lipid droplets; the latter are diminished and often irregular in contour. The BAT in winter specimens is distinguished also by a large amount of blood capillaries penetrating the tissue. In spring, mitochondria of BAT are found more frequently adhering to each other, and are characterized by loosely arranged cristae. In addition to the spherical lipid droplets, agglomerations of lipid material may be found in the cytoplasm. The observed seasonal fluctuations in the ultrastructure of BAT in the shrew correspond to the metabolic rhythm of this animal. The latter point is discussed.
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    Fine structure and function of interrenal (adrenocortical) cells of dexamethasone-treated trout (Salmo fario L.) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 641-649 
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    ISSN: 1432-0878
    Keywords: Adrenocortical cells ; Trout ; Ultrastructure ; Dexamethasone ; Cortisol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the interrenal (adrenocortical) cells of trout (Salmo fario L.) was studied after dexamethasone treatment. A procedure for identifying and isolating interrenal tissue fragments from the surrounding head kidney tissue prior to their preparation for electron microscopy is described. The peripheral plasma cortisol concentrations were measured in order to evaluate the steroidogenic activity of this tissue. The interrenal cells of control animals contain numerous mitochondria with tubular cristae, and a well developed and highly organized smooth endoplasmic reticulum (SER). The scarcity, or absence, of lipid droplets contrasts markedly with the abundance of SER. Treatment with dexamethasone results in a decrease steroidogenic activity of the interrenal cells, as indicated by the fall in plasma cortisol concentrations. The interrenal cells are small, but still contain numerous mitochondria. The SER is poorly developed, but masses of densely intermeshed smooth cisternae subsist. Lipid droplets do not accumulate in these cells; this peculiarity is discussed in connection with the virtual absence of liposomes in teleost interrenal cells.
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    Fine structural indications of an osmoregulatory function of the “gills” in terrestrial isopods (Crustacea, Oniscoidea) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 663-666 
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    ISSN: 1432-0878
    Keywords: Terrestrial isopods ; Gills ; Ultrastructure ; Smooth endoplasmic reticulum ; Osmoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In all species of Oniscoidea investigated the epithelial cells of the “gills” (=endopodites of pleopods) show the ultrastructural organization of transporting epithelia. Therefore it is assumed that also in the terrestrial isopods the pleopods are involved in respiration as well as osmoregulation.
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    An analysis of the integrity of the brachial motor unit in the dystrophic chick embryo (1981)
    Springer
    Cell & tissue research 215 (1981), S. 537-545 
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    ISSN: 1432-0878
    Keywords: Chick embryo ; Muscular dystrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In New Hampshire chickens, the primary clinical symptom of dystrophy is limitation of wing motility. Examination of the brachial-level motor unit in chick embryos homozygous for dystrophy reveals abnormalities in both muscular and neural components. Wing motility in these embryos is abnormal as early as six days, and there is a corresponding lack of differentiation of the pectoralis major muscle. The findings suggest that delayed development of brachial-level neuronal pathways is responsible for the decreased wing motility and early degeneration of the pectoral muscle.
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    The rat pituitary cleft: A correlated study by scanning and transmission electron microscopy (1981)
    Springer
    Cell & tissue research 215 (1981), S. 515-529 
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    ISSN: 1432-0878
    Keywords: Pituitary ; Rathke's cleft ; Ultrastructure ; Scanning electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary SEM reveals that the inner surface of the pituitary cleft is lined by a continuous layer of marginal cells possessing microvillous and ciliated apical surfaces. The ciliated cells are more numerous on the posterior side (toward the pars intermedia) than on the anterior side of the cleft (toward the pars distalis). In contrast small infoldings (crypts) were occasionally noted only on the marginal layer covering the distal part of the hypophysis. In some areas of the cleft the surface features of the marginal cells are rather similar to the epithelial cells populating the upper parts of the respiratory tract in their topography and distribution. In other regions they also show striking similarities with the ependymal cells (tanycytes) lining the lateral recesses of the 3rd ventricle and the infundibular process with which the pituitary cleft has a very close topographical relationship. The parenchymal cells of the pars distalis are closely related to the flattened marginal cells of the cleft. The intercellular spaces of the pars distalis form a three-dimensional labyrinthic series of cavities continuous with the submarginal spaces of the cleft. Further SEM and TEM results demonstrate that the majority of the microvillous marginal cells lining both sides of the cleft possess surface features such as bulbous protrusions, laminar evaginations and large cytoplasmatic vacuoles, which are very likely the expression of an active transport of fluids. On the basis of these results it is concluded that the fluid-like material (colloid) present in the pituitary cleft is mainly derived from the fluids contained in the lacunar spaces of the pars distalis. Thus, marginal cells by absorbing fluids from the cleft by active endocytosis, may transport to the pars intermedia material (or hormones) produced in the distal part of the gland and vice versa. The cilia present on many marginal cells, based on their 9+2 tubular pattern, possess a kynetic role. This is very similar to that shown by the ciliated cells of the ependyma lining the brain ventricles. The occurrence of ciliated cells within the pituitary parenchyma (mainly in the follicles) suggests that they probably arise from the ciliated cells populating the marginal layer of the cleft and with which the parenchyma cells are closely related.
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    URL: http://dx.doi.org/10.1007/BF00233528
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    Multinucleate Sertoli cells in aged human testis (1981)
    Springer
    Cell & tissue research 217 (1981), S. 259-266 
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    ISSN: 1432-0878
    Keywords: Sertoli cells ; Multinucleate cells ; Testis ; Ultrastructure ; Old age ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present investigation documents morphological characteristics of human Sertoli cells of aged males. Testicular material was obtained from 35 patients (age 62–84 years) with carcinoma of the prostate who had received no previous anticancer therapy. As revealed by light and electron microscopy the appearance of the germinal epithelium showed great individual variations. In all cases examined, however, the occurrence of multinucleate Sertoli cells was a common finding. In seminiferous tubules with intact spermatogenesis these cells closely resembled the normally occurring variants, whereas they displayed features reminiscent of immaturity in the absence of germ cells. It is hypothesized that the nuclei of Sertoli cells in the special situation of aging may resume the capacity to divide, an ability normally restricted to immature cells. Thus, mitosis without subsequent cytokinesis might be an explanation for the formation of multinucleate Sertoli cells.
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    URL: http://dx.doi.org/10.1007/BF00233579
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    Ultrastructure of neurons in the ventromedial nucleus or the hypothalamus in ovariectomized rats with or without estrogen treatment (1981)
    Springer
    Cell & tissue research 217 (1981), S. 451-470 
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    ISSN: 1432-0878
    Keywords: Ventromedial nucleus ; Ultrastructure ; Estrogen effects ; Secretory product ; Lordosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the ventrolateral and dorsomedial subdivisions of the ventromedial nucleus (VMN) of the hypothalamus was examined in ovariectomized/control and ovariectomized/estrogen-treated rats to compare neurons of these areas to other neurons (specifically the ventrolateral thalamus), and to determine the effects of estrogen on these cells. The neurons of the VMN contain a large nucleus with a prominent nucleolus, rough endoplasmic reticulum (RER), polysomes, a Golgi complex, coated, uncoated and dense-cored vesicles, lysosome-like bodies, inclusion bodies, multivesicular bodies, whorl bodies and myelin figures. Similar organelles were present in the neurons of the ventrolateral thalamus, although polysomes were more prominent, and the cells lacked dense-cored vesicles in the perikarya. Differences in the cells of the VMN between ovariectomized/control and ovariectomized/estrogen-treated rats included a more conspicuous stacking of the RER and greater number of dense-cored vesicles in the estrogen-treated group in both the ventrolateral and dorsomedial subdivisions. In both areas the differences were statistically significant, although more marked in the ventrolateral subdivision. In both VMN subdivisions, the increased stacking of the RER could be correlated with the greater number of dense-cored vesicles and may reflect increased biosynthesis of a secretory product.
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    Morphological and histochemical study of the endometrial effects of Ovral in the baboon (1981)
    Springer
    Cell & tissue research 217 (1981), S. 611-624 
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    ISSN: 1432-0878
    Keywords: Endometrium ; Baboon ; Oral contraceptive ; Ultrastructure ; Autophagic vacuoles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an effort to better understand changes induced by hormonal contraceptives, a group of female baboons were administered Ovral for a period of 9 months. During this time the endometrium was sampled by transcervical uterine biopsy from both the treated animals and from a control group. The biopsies were all obtained between 10 and 14 days of the treatment cycle or the normal menstrual cycle. The endometrial glandular cells from the treated animals exhibited an accelerated maturation compared with the controls. Ultrastructurally this was reflected by increased cell size, numerous long, slender microvilli on the apical membranes, and increased development of the Golgi complex. Differences were also observed in the predominant type of granule seen in the apical cytoplasm. After 3 and 6 months of treatment with Ovral, no significant differences were noted between groups or between animals within a group. However, after 9 months of treatment, the endometrium displayed differences from the earlier experimental groups as well as individual variations. The functional correlates of these observations are discussed and compared to human endometrium.
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    The reorganization of subcellular structure in muscle undergoing fast-to-slow type transformation (1981)
    Springer
    Cell & tissue research 220 (1981), S. 449-471 
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    ISSN: 1432-0878
    Keywords: Muscle ; Fiber type ; Ultrastructure ; Stereology ; Stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transformation of fast-twitch into slow-twitch skeletal muscle was induced in adult rabbits by chronic low-frequency stimulation and studied at the ultrastructural level. With the use of stereological techniques, a time course was established for changes in mitochondrial volume, sarcotubular system, and Z-band thickness for periods of stimulation ranging from 6 h to 24 weeks. T-tubules, terminal cisternae, and sarcoplasmic reticulum decreased at an early stage and reached levels typical of slow muscle after only 2 weeks of stimulation. Transformation of Z-band structure took place between 11/2 and 3 weeks after the onset of stimulation. Mitochondrial volume increased several fold over the first 3 weeks of stimulation, and fell rapidly after 7 weeks, although it still remained above the levels typical of slow muscle. Although there was no sign of degradation and regeneration of the muscle fibers themselves, considerable structural reorganization was evident at the subcellular level after 1 week of stimulation. The fibers passed through a less well organized transitional stage in which fibers could not be assigned to a normal ultrastructural category. After 3 weeks all of the stimulated fibers could be assigned to the normal slow-twitch category although some subcellular irregularities persisted even after 24 weeks. The ultrastructural alterations are discussed in relation to functional and biochemical changes in the whole muscle.
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    URL: http://dx.doi.org/10.1007/BF00216750
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    Structural changes in the pars intermedia of the cichlid teleost Sarotherodon mossambicus as a result of background adaptation and illumination (1981)
    Springer
    Cell & tissue research 220 (1981), S. 561-571 
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    ISSN: 1432-0878
    Keywords: Pineal organ ; MSH ; Background adaptation ; Sarotherodon mossambicus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The MSH producing cells in the pars intermedia of Sarotherodon mossambicus have been shown to be involved in background adaptation processes. Reflected light received by the eyes affects the activity of these cells. In the present study the hypothesis has been tested that also the pineal organ, as a second photoreceptor, is involved in regulation of the metabolic activity of the MSH cells. The pineal organ appears to contain photoreceptor cells and is considered to be capable of transferring information about light conditions to the animal. Removal of the pineal organ of fish kept on a black background has no effect on activity of MSH cells, whereas the activity of these cells in fish kept in darkness is increased. Thus it seems that the pineal organ exercises its influence on MSH cells only in darkness and that this influence results in a reduced activity of these cells. It is therefore concluded that the metabolic activity of MSH cells is inhibited not only by reflected light received by the eyes, but also by the action of the pineal organ as a result of the absence of illumination. No structural signs of secretory activity can be observed in the pineal, which might indicate synthesis or release of substances like melatonin. However, administration of melatonin reduces the activity of MSH cells. Neither pinealectomy nor treatment with melatonin has any influence on the second cell type of the pars intermedia, the PAS positive cells.
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    An ultrastructural and histochemical study of the axial musculature in the African lungfish (1981)
    Springer
    Cell & tissue research 220 (1981), S. 599-609 
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    ISSN: 1432-0878
    Keywords: Axial musculature ; Lungfish ; Histochemistry ; Ultrastructure ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Red, intermediate, and white axial muscle fibres of African lungfish were studied using histochemical techniques and electron microscopy. Gross dissection revealed the presence of a small wedge of red coloured muscle along the lateral line. This wedge was shown by histochemical demonstrations of lactate and succinate dehydrogenases, of adenosine triphosphatases, and of lipid to be composed of a mosaic of red and intermediate fibres measuring 23.63 and 34.30 μm in average diameter, respectively. The bulk of the myotome was composed of white fibres having an average diameter of 67.35 μm. Mitochondrial density, capillarity and lipid content were very low for all fibres. These data suggest that the axial musculature is geared primarily for anaerobic function. The mosaic arrangement of fibres, and the lack of a subsarcolemmal band of mitochondria suggests that the lungfish have a muscle organisation that is transitional between lower vertebrates and amphibians.
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    Ultrastructure of splenic white pulp of the turtle, Mauremys caspica (1981)
    Springer
    Cell & tissue research 220 (1981), S. 845-855 
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    ISSN: 1432-0878
    Keywords: Spleen ; Lymphoid tissue ; Reptiles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of splenic tissue of non-immunized turtles, Mauremys caspica, shows two areas, namely, the white pulp which is lymphoid in nature, and the red pulp which is formed by cell cords and sinusoids. Between both areas there is always a marginal zone with gaps through which cells leak. In the white pulp, there are two blood vessel types; one with muscled walls, and the other showing thinner walls sheathed by reticular cells. Reticular cells constitute a network where there occur dendritic macrophages, lymphoblasts and small and medium lymphocytes. Mature plasma cells are scarce in the white pulp.
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    Ultrastructure of the jugular body of Rana pipiens (1981)
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    Cell & tissue research 221 (1981), S. 193-202 
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    ISSN: 1432-0878
    Keywords: Jugular bodies ; Lymphoid organs ; Amphibians ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The jugular bodies in adult Rana pipiens, are surrounded by a capsule of mesothelium and connective tissue, and their parenchyma consists of cell cords arranged in a sinusoidal network. The cell cords are formed by irregular reticular cells, showing numerous filaments and joined together by zonulae adhaerents. The intercellular spaces are filled by reticular fibres and free cells. These latter are small and medium lymphocytes, lymphoblasts, and developing and mature plasma cells. Additionally, free macrophages, neutrophils and acidophils also occur. Sinusoidal blood vessels show thin walls with numerous filaments and pinocytotic vesicles. They exhibit a discontinuous basement membrane, and tight junctions frequently occur between endothelial cells. Occasionally, lymphatic vessels are found and the innervation is principally vasomotor, although nerve endings appear remarkably near reticular cells and lymphocytes. The jugular bodies of adult R. pipiens are plasma cell and antibody-forming organs, whose functional significance is discussed in relation to their ultrastructural organization.
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    Plasma cells in the ammocoete of Petromyzon marinus (1981)
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    Cell & tissue research 221 (1981), S. 203-208 
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    ISSN: 1432-0878
    Keywords: Plasma cells ; Spleen ; Ammocoete ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Ce travail démontre pour la première fois l'existence de plasmocytes murs et en développement dans la rate d'ammocètes de Petromyzon marinus non-immunisés. Les plasmocytes se présentent comme des cellules électroniquement denses avec de la chromatine condensée et un grand développement du réticulum endoplasmique granulaire. L'importance de cette découverte apparaît accentuée en relation avec l'évolution du système immunitaire.
    Notes: Summary This study demonstrates for the first time the presence of mature and developing plasma cells in the spleen of non-immunized ammocoetes of Petromyzon marinus. Plasmocytes occur as electron-dense cells with much condensed chromatin and an extensively large developed and dilated rough endoplasmic reticulum. The importance of this finding is emphasized in relation to the evolution of the immune system.
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    URL: http://dx.doi.org/10.1007/BF00216582
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    Distribution of calcium differs in relaxed and contracted myocardial cells of the rat (1981)
    Springer
    Cell & tissue research 221 (1981), S. 295-302 
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    ISSN: 1432-0878
    Keywords: Cardiac muscle cells ; Calcium ; Sarcomere ; Ultrastructure ; Contraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myocardial cells from left ventricles of beating hearts of rats were fixed by immersion in an osmium tetroxide solution containing potassium pyroantimonate to study the electron-microscopic distribution of calcium, the cation being precipitated as an electron-opaque salt (calcium antimonate) by this cytochemical technique. The observed myocytes could be divided into two groups according to their contractile state, evaluated by sarcomere length measurements. In contracted cells (mean sarcomere length 1.43 μm) the intramyoflbrillar precipitate was confined to areas of I-bands bordering the A-bands, the intermyofibrillar space showing scarce content in reaction product. Relaxed cells (mean sarcomere length 1.69 μm) presented a heavy deposition of reaction product over the sarcomeres, the electron-opaque dots being absent on the H and Z bands. The sarcotubular system and mitochondria were also clearly marked by the reaction product. This second pattern of calcium distribution has not been previously described in heart muscle cells and is interpreted as corresponding to the phase of rise of intracellular calcium which is mediated by membrane depolarization. Our results suggest that different bands of heart sarcomeres show different abilities to bind calcium. The I bands retain the cation even in cells under sustained contraction, probably due to their content in calmodulin; Z and M bands are apparently not involved in calcium sequestration, whereas the content in calcium of the A bands seems to be dependent on the contraction-relaxation cycle of heart myocytes.
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    Comparison of fast and slow synaptic terminals in lobster muscle (1981)
    Springer
    Cell & tissue research 221 (1981), S. 303-310 
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    ISSN: 1432-0878
    Keywords: Neuromuscular terminal ; Fast synapse ; Slow synapse ; Lobster ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Synaptic terminals of fast (FCE) and slow (SCE) excitatory neurons were physiologically identified on separate fibres of one muscle, the closer muscle in lobster claws. The innervation by these identified fibers was demonstrated over long distances (7–21 μm) by examining serial thin sections at periodic intervals. The ultrastructure of each type of innervation was consistent both qualitatively and quantitatively in two separate samples. The FCE innervation is relatively simple in having consistently small-diameter terminals each forming a single long synapse, with few synaptic vesicles, and little if any postsynaptic apparatus. The SCE innervation is more complex in having larger-diameter but more variable terminals forming several short synapses, with many synaptic vesicles and an extensive postsynaptic apparatus. These differences in the size of the synapses and the number of synaptic vesicles parallel differences in transmitter release and fatigue sensitivity characteristic of the two types of innervation. The degree of elaboration of the postsynaptic apparatus may reflect differences in the amount of transmitter taken up after release. Our data reveal for the first time in a single muscle differences between FCE and SCE innervation previously reported in different muscles and in different species.
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    Fine structure and function of the prosomal glands of the two-spotted spider mite, Tetranychus urticae (Acari, Tetranychidae) (1981)
    Springer
    Cell & tissue research 221 (1981), S. 339-349 
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    ISSN: 1432-0878
    Keywords: Prosomal glands ; Spider mite ; Tetranychus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The prosomal glands of Tetranychus urticae (Acari, Tetranychidae) were examined light and electron microscopically. Five paired and one unpaired gland are found both in females and males. The silk spinning apparatus consists of paired silk glands which extend laterally on both sides of the esophagus into the pedipalps. There, they enter the terminal silk gland bag which opens into a silk bristle at the apex of the pedipalps. The salivary secretions are formed in three paired glands which have an interconnecting duct, the podocephalic canal. The dorsal podocephalic glands may produce a serous secretion, the anterior podocephalic glands a mucous secretion, and the coxal organ may add a liquid, ion-rich secretion. These secretions pass the podocephalic canal and reach the mouth at the apex of the gnathosome. The function of the paired tracheal organs and the unpaired tracheal gland is still unclear. The tracheal gland may produce a secretion which facilitates the movement of the fused chelicerae and the stylets.
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    Electron-microscope study of the dentine-enamel junction of kangaroo (Macropus giganteus) teeth using selected-area argon-ion-beam thinning (1981)
    Springer
    Cell & tissue research 221 (1981), S. 405-419 
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    ISSN: 1432-0878
    Keywords: Teeth (Marsupials) ; Enamel ; Dentine ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission electron microscopy of selected-area argon-ion-beam thinned kangaroo (Macropus giganteus) enamel revealed a complex ultrastructure in the region of the dentine-enamel junction (DEJ). Characteristic features were multiple branching of dentinal tubules, rejoining of enamel tubules, elongated defects, extended protrusions of dentine into enamel, two types (A and B) of hypomineralized enamel and a continuity between dentinal and enamel tubules. In the intertubular regions of the DEJ a complex intermingling of finer enamel and dentine crystals, similar to that found in human enamel, was observed. The varicosities observed in the light microscope were a combined optical effect caused by the hypomineralized (type A) enamel and the branching and rejoining of the enamel tubules.
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    Ultrastructure of elastic cartilage in the rat external ear (1981)
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    Cell & tissue research 218 (1981), S. 149-160 
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    ISSN: 1432-0878
    Keywords: Elastic cartilage ; External ear ; Rat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of elastic cartilage in the external ear of the rat was investigated by transmission and scanning electron microscopy. The narrow subperichondrial, boundary zone contains predominantly ovoid cells rich in cell organelles: mitochondria, Golgi complex, granular endoplasmic reticulum and small (40–100 nm) vesicles. Scarce glycogen granules and bundles of 6–7 nm cytoplasmic filaments are also present. Deeper in the boundary zone, one or more cytoplasmic lipid droplets appear and cytofilaments become more abundant. Fully differentiated chondrocytes in the central zone of the cartilage plate resemble white adipose cells. They are globular and contain a single, large cytoplasmic lipid droplet. The cytoplasm is reduced to a thin peripheral rim; it contains a flattened nucleus, few cytoplasmic organelles and abundant, densely packed, cytoplasmic filaments. The intercellular matrix is very sparse. The pericellular ring consists of collagen fibrils about 20 nm in diameter and a proteoglycan cartilage matrix in the form of a “stellate reticulum”. The complex of these two structures appears in the scanning electron micrographs as a network of randomly oriented, ca 100 nm thick fibrils. Spaces between pericellular rings of matrix also contain thick elastic fibers or plates, apparently devoid of microfibrils. In scanning electron micrographs elastic fibers could be detected only in a few areas, in which they were not obscured by other constituents of the matrix. Immature forms of elastic fibers, oxytalan (pre-elastic) and elaunin fibers, were found in the perichondrial and boundary zones.
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    Specializations for excitation-contraction coupling in the podial retractor cells of the starfish Stylasterias forreri (1981)
    Springer
    Cell & tissue research 218 (1981), S. 475-485 
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    ISSN: 1432-0878
    Keywords: Excitation-contraction coupling ; Podium ; Retractor cells ; Starfish ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural examination of the podium of the asteroid echinoderm Stylasterias forreri has revealed that cells of the coelomic epithelium and cells of the retractor muscle should be considered as components of a single epithelium. The podial retractor cells are, therefore, myoepithelial in nature. This report concentrates on those ultrastructural features of the retractor cells that are most likely involved with excitation-contraction coupling. The spatial arrangement of the sarcoplasmic reticulum, the couplings between the sarcoplasmic reticulum and sarcolemma, and an intramembranous specialization of the sarcolemma are documented and discussed. Current concepts regarding the innervation of the retractor cells of the podium and the protractor cells of the ampulla are reviewed, and specific proposals for further investigation of podial innervation are outlined.
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    Ultrastructure of the coelomic lining in the podium of the starfish Stylasterias forreri (1981)
    Springer
    Cell & tissue research 218 (1981), S. 449-473 
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    ISSN: 1432-0878
    Keywords: Coelomic lining ; Myoepithelium ; Podium ; Starfish ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural examination of the podium of the asteroid echinoderm Stylasterias forreri reveals that cells of the coelomic epithelium and cells of the retractor muscle are, in fact, components of a single epithelium. The basal lamina of this unified epithelium adjoins the connective tissue layer of the podium. The principal epithelial cells in the coelomic lining are the flagellated adluminal cells and the myofilament-bearing retractor cells. Adluminal cells interdigitate extensively with each other and form zonular intermediate and septate junctions at their apicolateral surfaces. The adluminal cells emit processes which extend between the underlying retractor cells and terminate on the basal lamina of the epithelium. Retractor cells exhibit unregistered arrays of thick and thin myofilaments. The periphery of the retractor cell is characteristically thrown into keel-like folds which interdigitate with the processes of neighboring cells. Specialized intermediate junctions bind the retractor cells to each other and anchor the retractor cells to the basal lamina of the epithelium. The retractor cells are not surrounded by external laminae or connective tissue envelopes. It is concluded that the coelomic lining in the podium of S. forreri is a bipartite epithelium and that the retractor cells of the podium are myoepithelial in nature. There are no detectable communicating (gap) junctions between the epithelial cells of the coelomic lining.
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    Intranuclear inclusion bodies within neurons of spinal and cranial ganglia in three cyprinid species (1981)
    Springer
    Cell & tissue research 218 (1981), S. 529-536 
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    ISSN: 1432-0878
    Keywords: Intranuclear inclusions ; Neurons ; Cyprinids ; Histochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A histological examination of 205 fish representing four cyprinid species from a site 2.5 miles north of Wheeling, West Virginia, on the Ohio River revealed large (2–4 μm) cuboidal intranuclear inclusion bodies (NIB's) within neurons in the cranial and spinal ganglia of three species. Because the minnows had been caught during a yearly sampling of fish, an additional 63 minnows were taken the following year. Inclusions were again observed. The NIB's stain strongly with phloxine as well as with Mallory and Giemsa stains, appearing bright red or pink. Various histochemical tests indicated that the inclusions contain protein and lipid but no carbohydrates or nucleic acids. No heavy metals were detected by electron probe analysis. At the ultrastructural level the inclusions exhibit subunits resembling hexagons measuring 326–350 nm. Previously suggested causes for such inclusions include effects of viruses, aging, drugs, cellular transformation, and an altered metabolic state of affected cells.
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    Ultrastructural and cytochemical effects of trypan blue on TSH stimulation of thyroid follicular cells (1981)
    Springer
    Cell & tissue research 218 (1981), S. 547-556 
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    ISSN: 1432-0878
    Keywords: Thyroid stimulating hormone ; Trimetaphosphatase ; Ultrastructure ; Lysosomes ; Trypan blue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and cytochemical techniques were used to study the effects of trypan blue on the response of mouse-thyroid cells to exogenous stimulation by thyroid stimulating hormone (TSH). The dye delayed the response to TSH resulting in decreased colloid-droplet formation in the apical region of the cells. The dye did not stop the shift of trimetaphosphatase activity from lysosomes to phagolysosomes. The duration of the TSH-induced response was shorter in the dye treated thyroids. Small vesicles, with trimetaphosphatase reaction product, were found near Golgi elements, phagolysosomes, and the plasma membrane facing the intercellular space of adjacent follicle cells. Their enzyme activity was not affected by exposure to the dye. These data indicate that the primary effect of trypan blue on the response of thyroid follicle cells to TSH stimulation was reduced endocytosis in the apical region resulting in fewer colloid droplets.
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    Fine structure of the gastric mucous and endocrine cells of the toad, Bufo marinus (1981)
    Springer
    Cell & tissue research 218 (1981), S. 663-668 
    Details
    ISSN: 1432-0878
    Keywords: Amphibia ; Ultrastructure ; Gastric mucosa ; Cytochemistry ; Secretory granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the mucous and endocrine cells of the gastric mucosa of the cane toad (Bufo marinus) has been examined. Surface mucous cells line the entire gastric mucosa and pits. Many of their secretory granules contain an electron-dense core that remains unreactive after cytochemical testing for glycoproteins. A second spatially and structurally discrete population of mucous cells is present in the gastric glands. These glandular mucous cells are probably homologous with the antral gland and mucous neck cells of mammals; their secretory granules also contain non-glycoprotein cores. Three distinct populations of endocrine cells show structural homologies with gastric hormone-storing cells of higher vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210123
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  • 76
    Electronic Resource
    Electronic Resource
    Subcellular distribution of ionic components in gastric mucosa of the guinea pig (1981)
    Springer
    Cell & tissue research 219 (1981), S. 143-158 
    Details
    ISSN: 1432-0878
    Keywords: Stomach ; Guinea pig ; Electrolyte distribution ; Acid secretion ; Ultrastructure ; Carbohydrate cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The topographical distribution of cations, anions and polyanions in the guinea-pig stomach has been studied by ultrastructural cytochemical methods. After fixation with the pyroantimonate-osmium tetroxide solution, variable-sized precipitates were localized in the basolateral extracellular space bordering parietal cells or chief cells but not in that bordering mucus-secreting cells. The basal lamina of all gastric cells disclosed a continuous layer of heavy antimonate deposits. Parietal cells disclosed uniformly fine deposits also on the apical plasmalemma both at the main lumen and in the intracellular canaliculi, and revealed, as well, coarse precipitates in the mitochondria. Fixation with a silver acetate-osmium tetroxide solution yielded nitric acid-resistant, silver deposits confined to the luminal surface of the apical plasmalemma in the main lumen and intracellular canaliculi, the lateral intercellular space, the outer surface of the basal plasmalemma and the basal lamina of the parietal cell. Staining with dialyzed iron demonstrated a glycocalyx rich in acid mucosubstance on the basolateral plasmalemma but not on the apical plasmalemma of parietal cells. In contrast, acid glycoconjugate was visualized on the apical plasmalemma of isthmus cells, mucous neck cells and the transitional cell between isthmus and mucous neck cells but little or no acidic glycoconjugate was demonstrated on the basolateral plasmalemma of these cells. The entire plasmalemma of gastroendocrine cells, unlike other epithelial cells, stained uniformly for acidic glycoconjugate. The dialyzed iron and high iron diamine methods stained the outer compartment of mitochondria in parietal cells intensely and that in other gastric cells lightly. These reagents stained the basal lamina of all gastric cells as did ruthenium red. The several characteristic cytochemical properties of parietal cells presumably relate to the unique secretory activity of these cells and are consistent with the view of the intracellular canaliculi of the parietal cell as the main route for hydrogen and chloride ion secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210024
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  • 77
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    Electronic Resource
    Ultrastructural study of the endothelial cells in teleost liver sinusoids under normal and experimental conditions (1981)
    Springer
    Cell & tissue research 219 (1981), S. 649-657 
    Details
    ISSN: 1432-0878
    Keywords: Endothelial cells ; Liver sinusoids ; Teleost ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the endothelial cells of liver sinusoids was studied in the teleost, Pimelodus maculatus. These cells have the ability to form pinocytotic vacuoles, starting with the formation of marginal folds. The latter occur in many cells after stimulation by India ink injections and ink particles are ingested by pinocytosis and by micropinocytosis. Desmosomes, structures rarely described between liver sinusoidal endothelial cells, are present in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210002
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  • 78
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    Electronic Resource
    Full-term and prematurely ruptured fetal membranes (1981)
    Springer
    Cell & tissue research 220 (1981), S. 263-278 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Chorion ; Amnion ; Fetal membranes ; Prematurity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The layers of the human amnion and chorion were examined by light and transmission electron microscopy. Comparisons among different anatomical sites with respect to full-term and prematurely ruptured membranes indicate that (a) the thickness of the membranes is reduced near the rupture point; (b) intercellular canals near the implantation site become dilated and branched; (c) the trophoblast layer of full-term membranes is thinner and with more degenerating cells; and (d) the fibroblast and spongy layers have fewer collagenous fibers and less organization near the rupture site. These findings suggest that, although cellular activity is maintained in prematurely ruptured membranes, the mainly collagenous extracellular matrix undergoes marked disorientation. If this occurs too early in gestation, it may lead to premature rupture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210508
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