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  • Electron microscopy  (68)
  • Bone
  • Calcium
  • Springer  (90)
  • Cambridge University Press
  • Frontiers Media
  • 2020-2022
  • 1980-1984
  • 1975-1979  (90)
  • 1978  (90)
Collection
Keywords
Publisher
  • Springer  (90)
  • Cambridge University Press
  • Frontiers Media
Years
  • 2020-2022
  • 1980-1984
  • 1975-1979  (90)
Year
  • 1
    Electronic Resource
    Electronic Resource
    The morphology of bone mineral crystals (1978)
    Springer
    Calcified tissue international 25 (1978), S. 217-222 
    Details
    ISSN: 1432-0827
    Keywords: Bone mineral ; Electron microscopy ; X-ray diffraction ; Dark field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Electron microscopical observations of the size and shape of bone mineral crystallites have not been in complete agreement with X-ray diffraction findings. The two prevalent viewpoints consider bone mineral crystals to be either rod, or plate like in habit. There appears to be agreement that the smallest dimension of the crystals is about 5 nm, but there is discrepancy in the reported c-axial lengths. The method of dark field imaging is used to obtain a quantitative measurement of the c-axial length distribution in rabbit, ox and human bone: mean c-axial lengths 32.6 nm, 36.2 nm and 32.4 nm, respectively, show no significant difference at the 5% level to the mean c-axial length measured by X-ray line broadening. Both bright and dark field images strongly suggest that bone mineral has a plate like form. Reasons for past discrepancies are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010772
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  • 2
    Electronic Resource
    Electronic Resource
    Scanning electron microscope study of separated calcospherites from the matrices of different mineralizing systems (1978)
    Springer
    Calcified tissue international 26 (1978), S. 47-49 
    Details
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Calcospherites ; Mineralization ; Bone ; Dentin ; Cartilage ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Mineral particle cluster, corresponding to calcospherites or matrix vesicle-initiated clusters in calcifying cartilage and dentin and to collagen bundle-related mineralization in lamellar bone, have been isolated from NaOCl solutions used to dissolve the organic matrix in preparation of anorganic mineralizing fronts for scanning electron microscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013233
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanism of osteoclastic bone resorption: A new hypothesis (1978)
    Springer
    Calcified tissue international 26 (1978), S. 81-84 
    Details
    ISSN: 1432-0827
    Keywords: Osteoclasts ; Bone ; Resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Osteoclastic bone resorption involves the solubilization of the mineral salts and the degradation of noncollagen bone matrix and collagen fibrils. As no recognizable collagen fibrils have ever been reported within cytoplasmic vacuoles in osteoclasts, it is generally assumed that the collagen fibrils are digested extracellularly in the resorption zone. The extent to which lysis occurs extracellularly and whether or not the osteoclasts phagocytose the degradation products remain to be established. In the present communication, a hypothesis is presented suggesting the possibility that osteoclastic resorption of bone involves the participation of two different cell types. According to this hypothesis, osteoclastic bone resorption is initiated by osteoclasts that demineralize areas of bone and degrade noncollagen bone matrix. After the osteoclasts have moved away or become partially detached from the demineralized site, the exposed collagen fibrils are phagocytosed by mononuclear, fibroblast-like or monocyte-derived cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013238
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  • 4
    Electronic Resource
    Electronic Resource
    Plasma disappearance of rabbit α2 HS-glycoprotein and its uptake by bone tissue (1978)
    Springer
    Calcified tissue international 26 (1978), S. 155-161 
    Details
    ISSN: 1432-0827
    Keywords: Plasma protein ; Glycoprotein ; Bone ; Glucosamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Plasmaα 2HS-glycoprotein is specifically accumulated in calcified tissues. In the present studies this glycoprotein was isolated from plasma and after iodination with iodine-125 was injected intravenously into young rabbits. The tissue distribution and plasma disappearance rate of this radioactively labeled material were determined. Of the various tissues studied, bone showed the greatest retention of labeled glycoprotein expressed as percentage of the injected dose per gram tissue relative to the plasma content. The rate of loss of iodinatedα 2HS-glycoprotein from plasma was similar to that ofα 2HS-glycoprotein labeled endogenously by using14C-glucosamine or3H-glucosamine. The uptake of exogenously labeled3I-α 2HS-glycoprotein into bone tissue expressed as a percentage of the injected dose was similar to that of endogenously labeled14C-α 2HS-glycoprotein. These results suggest that the125I-labeled material can be used to study further the metabolism ofα 2HS-glycoprotein by bone tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013251
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of mithramycin on boneβ-glucuronidase and resorption (1978)
    Springer
    Calcified tissue international 26 (1978), S. 209-213 
    Details
    ISSN: 1432-0827
    Keywords: Mithramycin ; Bone ; β-Glucuronidase ; KT medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Mithramycin suppresses bone resorption. Its effect on the synthesis and release of β-glucuronidase (a referent for lysosomal enzymes) in mouse calvarial explants was studied in an in vitro culture system. A newly described medium (designated as KT medium) was introduced in this specific study. Mithramycin initially inhibited the release of β-glucuronidase into the medium and resulted in an ultimate accumulation of this enzyme in the bone. These results suggest that inhibition of bone resorption by mithramycin may be attributed to interference in release of lysosomal enzymes from bone cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013260
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative morphogenetic investigations on fine structural changes in the optic tectum of the rainbow trout (Salmo gairdneri) during ontogenesis (1978)
    Springer
    Development genes and evolution 184 (1978), S. 83-94 
    Details
    ISSN: 1432-041X
    Keywords: Synaptogenesis ; Electron microscopy ; Visual acuity ; Fish development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The morphogenetic differentiation of synapses of the optic tectum of the rainbow trout was investigated at different stages of development (from hatching to adult) and compared with the improvement in visual discrimination (minimum separable). (1) The main phase of synaptogenesis (increase in number of synapses, length of contact zone and number of vesicles) begins about one week after hatching and continues up to the age of one month, when the larvae start swimming freely. (2) Myelination begins 26 days after hatching and induces the end of the synaptogenesis period. (3) The visual discrimination (minimum separable) of trout larvae improves from 30 degrees of arc on the 10th day after hatching to 1 degree on day 30, then to about 14 to 18 min of arc in the adult. The results are discussed with special reference to previous biochemical investigations on changes in the ganglioside composition of the trout brain during comparable periods of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848671
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  • 7
    Electronic Resource
    Electronic Resource
    The intestinal handling of calcium by the rat in vivo, as affected by cortisol. Effect of dietary calcium supplements (1978)
    Springer
    Calcified tissue international 25 (1978), S. 1-6 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Intestine ; Growth ; Cortisol ; Hydroxyproline ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This paper reports the effects of cortisol on intestinal management of calcium and on related changes on bone metabolism. Five groups of 12 rats each fed a standard diet (0.8% Ca) received 2, 6, 16, 32, and 128 mg/kg/day of cortisol hemisuccinate, subcutaneously. After 16 days, intestinal absorption and excretion of Ca were measured with the aid of45Ca. True Ca absorption increased as a function of dose up to 16 mg/kg/day and remained high with the larger doses. Endogenous fecal Ca excretion increased exponentially as a function of the dose from 16 mg/kg/day onwards. Therefore, a dual effect was observed: (a) an increase in true Ca absorption at low cortisol doses (which increased net Ca absorption); and (b) an increase in endogenous fecal Ca excretion at high doses (which reduced net Ca absorption). In no case was a depression of true Ca absorption observed. Growth rate and food conversion efficiency were depressed only with a cortisol dose of 128 mg/kg/day. The urinary excretion of hydroxyproline, pyrophosphate, and aminopolysaccharides decreased with low doses and increased above normal levels with the highest dose. When animals treated with 128 mg/kg/day of cortisol were fed Ca-enriched diets, net Ca absorption improved. Simultaneously, growth rate and food conversion efficiency approached normal values. In these experiments, net absorption of Ca was found to be inversely related to urinary excretion of hydroxyproline. The urinary rate of excretion of hydroxyproline is suggested as an indicator of the effect of a Ca supplement on cortisol affected connective tissue turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010743
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  • 8
    Electronic Resource
    Electronic Resource
    Cellular calcium distribution in fetal bones studied with K-pyroantimonate (1978)
    Springer
    Calcified tissue international 26 (1978), S. 181-190 
    Details
    ISSN: 1432-0827
    Keywords: Cellular calcium ; Electron microscopy ; Osteoblasts ; Chondrocytes ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The calcium distribution in cartilage and bone cells during beginning ossification of fetal mouse long bones was studied after fixation with 2% K-pyroantimonate in 1% osmium. In the developing periosteum, the future osteoblasts showed a sparse cation-antimonate precipitate over the cytoplasm. In young osteoblasts the precipitate was accumulated on the mitochondrial membranes and the plasmalemma. Both organelles were sharply outlined by precipitate in the mature osteoblasts at the onset of mineralization. X-Ray microprobe analysis of these organelles demonstrated the presence of both Sb and Ca. In the extracellular compartment, a collagen-associated precipitate with 50 to 60 nm periodicity appeared during osteoblastic differentiation. During the initial phase of matrix mineralization, a random gross precipitate appeared in the matrix and seemed to be accumulated by osmiophilic matrix vesicles while the collagen fibrils lost their precipitate. Subsequently, during the confluent phase of matrix mineralization, the precipitate rapidly disappeared from the cells, leaving them devoid of precipitate once they were surrounded by mineralized matrix. Similar changes were found in the chondrocytes of the growth plate, but cartilage collagen, unlike osteoid collagen, did not bind precipitate. The results indicate that both osteoblasts and calcifying cartilage cells bind calcium prior to matrix mineralization. Bone collagen has strong pyroantimonate binding capacity, but it is not directly involved with initial stages of matrix mineralization, which starts in close association with matrix vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013254
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  • 9
    Electronic Resource
    Electronic Resource
    Radiogenic free radicals as molecular probes in bone (1978)
    Springer
    Calcified tissue international 25 (1978), S. 37-43 
    Details
    ISSN: 1432-0827
    Keywords: ESR ; Radiation free radicals ; CO3-Apatites ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Exposure of bone mineral to X-rays generates free radicals. These are usually very labile, but can be stabilized at liquid nitrogen temperatures for study by electron spin resonance spectroscopy. The free radicals thus detected in the present study included one with resonances arising from an electron excess center and 2 species with electron-deficit centers: a phosphate anion radical and a radical associated with carbonate. Each of these radicals seemed to be located chiefly at the mineral surface and was sensitive to the surface environment. Presence of an organic phase, as in whole bone, modified free radical production in a manner that suggests interference with the formation of electron deficit centers. Comparison with other synthetic minerals suggests that precipitated carbonateapatites are good models for bone mineral.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010749
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of a single dose of fluoride on calcium metabolism (1978)
    Springer
    Calcified tissue international 26 (1978), S. 199-202 
    Details
    ISSN: 1432-0827
    Keywords: Fluoride ; Calcium ; Phosphate ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Fluoride 27 mg was given perorally to 14 subjects. It was found that the serum fluoride concentration increased followed by a decrease to normal levels during 24 h. Serum concentrations of calcium and phosphate decreased initially whereas those of serum immunoreactive parathyroid hormone increased. After 24 h the measured quantities were within normal limits. The results are discussed with reference to mineralization of hard tissues and to fluoride treatment of osteoporotic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013258
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  • 11
    Electronic Resource
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    Potentiation of the effects ofSolanum malacoxylon extracts on rat intestinal phosphate and calcium absorption by incubation with ruminal fluid (1978)
    Springer
    Calcified tissue international 26 (1978), S. 215-219 
    Details
    ISSN: 1432-0827
    Keywords: Solanum malacoxylon ; Vitamin D metabolites ; Rickets ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of a partially purified aqueous extract ofSolanum malacoxylon (SM) leaves and of an SM extract incubated with ruminal fluid (RF) prior to administration on intestinal phosphate and calcium absorption in rachitic rats were compared with 1α, 25-dihydroxy-vitamin D3[1α,25-(OH)2-D3] using a duodenal loop in situ method. The time course responses elicited by both extracts were qualitatively similar to that of 1α, 25-(OH)2-D3. However, a single dose of SMRF was significantly more effective in stimulating32P absorption than an equivalent dose of SM. Part of this difference can be accounted for by incomplete saturation of the phosphate transport system with the level of SM employed. Treatment with rumen potentiated the effects of SM on45Ca absorption to a lesser extent. Extraction of SMRF with nonpolar organic solvents and purification of the lipid extract by chromatography on Silica Gel G thin-layer plates and on Sephadex LH-20 columns yield two fractions which promote intestinal32P absorption. The bioactive fraction eluting first from the Sephadex LH-20 column migrates similarly as 1α,25-(OH)2-D3. The greater effectiveness of SMRF extracts on intestinal phosphate and calcium absorption may be tentatively attributed to the release of 1α,25-(OH)2-D3 from the corresponding glycoside, shown previously to be present in SM, and to steroid modification during incubation with rumen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013261
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  • 12
    Electronic Resource
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    Selective stimulation of net calcium efflux from chick embryo tibiae by parathyroid hormone in vitro (1978)
    Springer
    Calcified tissue international 25 (1978), S. 227-232 
    Details
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Bone ; Calcium ; Chick embryo ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of this study was to measure in an in vitro system the movement of Ca and phosphate (Pi) out of bone when treated with parathyroid hormone (PTH). Tibiae from 13-day chick embryos were incubated for up to 8 h in a defined medium containing 1.8 mM Ca. Medium samples were collected every 2 h and were analyzed for Ca, Pi and lactate. Net effluxes from the bones were calculated. When bones were incubated with PTH in the medium (1 U/ml), net Ca efflux was increased 44, 60 and 100% at 4, 6 and 8 h, respectively. At no time was net Pi efflux affected by the hormone. The well known PTH-stimulated lactate production was not seen until 8 h. Lower doses of PTH (0.1 and 0.3 U/ml) were also effective. Comparing PTH (1 U/ml) responsiveness at higher (2.2 mM) and lower (0.9 mM) medium Ca concentrations, showed that with 2.2 mM Ca no increased Ca efflux was seen, while with 0.9 mM Ca significant elevation in medium Ca occurred 2 h sooner than in the experiments using 1.8 mM Ca. In another experiment, varying the medium Pi level from 1 to 2 mM had no effect on the Ca response to PTH. In neither experiment was Pi release affected by PTH. The results of this study have led to the following conclusions: (1) PTH acts on bone to cause an early dose related increase in net Ca efflux; (2) the effect is specific for Ca, since it is not accompanied by an increased Pi efflux, and may be saturated by raising the medium Ca level; and (3) PTH-stimulated Ca efflux in this system is not correlated with, and is probably not a result of increased lactate production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010774
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  • 13
    Electronic Resource
    Electronic Resource
    A bone resorbing substance from bovine serum albumin (brA) (1978)
    Springer
    Calcified tissue international 25 (1978), S. 233-240 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Bone resorption ; Albumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A fraction (brA), which causes resorption of fetal rat bones in vitro, has been concentrated from bovine serum albumin by anion exchange column chromatography on DEAE Sephadex. This active fraction has also been prepared using DEAE Sephadex A-50 by a batch method with a 0.09M NaCl, 0.1M TRIS buffer, pH 8.35. BrA was 10–30 times more potent than the original albumin. The retained material, which constitutes the bulk of the protein and has less activity than the original albumin, elutes with 0.45M NaCl. Similar treatment of serumα,β or γ globulins does not yield brA. Further enhancement of the bone resorbing activity of brA can be obtained with (NH4)2SO4 fractionation or extraction with CH3OH∶CHCl3. Heating at 55° C for 2 h or at 100° C for 10 min does not affect the activity; overnight incubation with protease destroys the bone resorbing effect. The bone resorbing activity is not removed by dialysis and does not correlate with the protease activity of the fraction. The action of brA is inhibited by 3 mM PO4, 1 μg/ml calcitonin or glucagon, 10−7 M dexamethasone or 0.02 μg/ml actinomycin D. The bone resorbing activity of brA is partially inhibited by 10−7–10−5 M indomethacin. PTH did not elicit bone resorption when added to cultures incubated in chemically defined medium supplemented with 0.1 mg/ml brA. However, brA did not inhibit PTH-induced resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010775
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  • 14
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    The fine structure of decalcified cartilage and bone: A comparison between decalcification procedures performed before and after embedding (1978)
    Springer
    Calcified tissue international 25 (1978), S. 179-190 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Calcified matrices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The ultrastructure of calcifying cartilage and bone has been examined under the electron microscope after using three different methods of decalcification. The first was carried out before embedding (by soaking specimens in EDTA or formic acid), the second after embedding (by floating ultrathin sections on formic acid), and the third after embedding (by soaking embedded specimens in EDTA or formic acid), and with later re-embedding. The first procedure invariably induces drastic changes in the fine structure of the cells and calcified matrix, probably as a results of the extraction of organic material along with extraction of mineral. The second and third procedures make it possible to preserve ultrastructural details perfectly in both cells and calcified matrix. Of the two, the third procedure is preferable because of its greater simplicity. In areas that are still calcifying, these post-embedding decalcification techniques reveal the presence of crystal-associated, filamentous organic structures which are not recognizable in specimens decalcified before embedding. These structures, which could have a key role in inducing and regulating crystal formation and growth, are less evident in fully calcified areas (but not at their borders). This may partly be due to the loss of glycan components in the matrix during calcification. The most important determinant, however, seems to be the fact that during calcification the components of the matrix, including collagen fibrils, are involved in an aggregation process which reduces the amounts of free chemical groups available for reaction with the stain solution. Because post-embedding decalcification does not disturb this state of aggregation, the stainability of the matrix and the electron microscopic evidence of its components remain very low.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010766
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  • 15
    Electronic Resource
    Electronic Resource
    Oestrogen binding proteins in bone cell cytosol (1978)
    Springer
    Calcified tissue international 25 (1978), S. 249-254 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Oestrogens ; Oestrogen receptors ; Binding proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Attempts were made to demonstrate the presence of specific oestrogen binding proteins (“receptors”) in bone cells. High speed cytosol preparations of bone were incubated with several concentrations of radioactive oestradiol alone and with radioactive oestradiol in the presence of a specific antioestrogen, Nafoxidine. Separation of bound and free oestradiol was carried out by dextran coated charcoal treatment and by sucrose gradient ultracentrifugation. Several types of bones likely to be oestrogen-sensitive were investigated: human femoral heads, human phalanx, rat and rabbit calvaria, humeri and femora of female rats. In all experiments we were unable to demonstrate the presence of specific oestrogen receptors in bone cell cytosol indicating that the direct effect of oestrogens on bone, if present, is not mediated by specific oestrogen receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010778
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  • 16
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    Influence of partially purified extracts ofSolanum malacoxylon on bone resorption in organ culture (1978)
    Springer
    Calcified tissue international 26 (1978), S. 39-45 
    Details
    ISSN: 1432-0827
    Keywords: Solanum malacoxylon ; Bone culture ; Resorption ; Calcium ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The water-soluble active principle of the plantSolanum malacoxylon (SM) was partially purified by column chromatography, and its bone-resorbing activity was tested by using an organ culture system of 18-day fetal mouse fibulae prelabeled with45Ca. Three series of experiments were performed. In the first series, the aqueous extract of SM was submitted to Sephadex G-25 chromatography to separate the active substances. From six collected fractions only two exhibited reproducible bone-resorbing activity as indicated by an increased release of45Ca from bone rudiments. In the second series, the active fractions were combined and lyophilized to a powder which was dissolved in the culture media to obtain the concentrations of 5, 25, 50, and 100 μg/ml. The addition of this saltfree material resulted in a dose-related accentuation of45Ca release from fetal mouse bones into the medium. Histologically, the treated fibulae showed greater numbers of osteoclasts than the controls and a disappearance of bone trabeculae. In the third series, the active material was further purified on Sephadex LH-20 column. From four collected fractions, only one showed bone-resorbing activity in vitro. It is concluded that the purified active factor of SM exerts a direct effect on bone. It stimulates the mobilization of bone calcium in vitro by increasing the population of osteoclasts. The nature of the active principle remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013232
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  • 17
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    A proposed cellular mechanism for calcium transport in the intestinal epithelial cell (1978)
    Springer
    Calcified tissue international 26 (1978), S. 71-79 
    Details
    ISSN: 1432-0827
    Keywords: Absorption ; Calcium ; Mitochondria ; Intestinal epithelium ; Potassium-pyroantimonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Intracellular transport of calcium from the apical to the basal-lateral region of the intestinal epithelial cell was invetigated in duodenum from normal fed, fasted, and calcium-loaded rats. The process was followed with time using electron microscopy with potassium pyroantimonate to precipitate calcium. The observations made were subjected to morphometric analysis. The specificity of the method was demonstrated in the villus cell by resistance to micro-incineration and by absence of deposits following exposure to EGTA. Using this method calcium was seen in cells from calcium-fed rats at the microvillus border, in the Golgi zone, and within the internal compartments of the mitochondria. In cells from fasted rats calcium was not seen. Mitochondria were found largely at the apex of the cell and were free of detectable calcium. By 5 min, in the cells of fasted rats given a calcium load, the calcium had reached the Golgi apparatus and the inner mitochondrial compartment. After 15 min mitochondria were heavily loaded with calcium and had moved to the basal region of the cell. These observations suggest that mitochondria play an important role in absorption of calcium and appear to transport this ion from the apex to the basal region of the cell where entry into the capillaries takes place.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013237
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  • 18
    Electronic Resource
    Electronic Resource
    Quantitative histology of bone: A computerized method of measuring the total mineral content of bone (1978)
    Springer
    Calcified tissue international 26 (1978), S. 85-89 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Histology ; Microradiography ; Densitometry ; Computer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A comparatively simple quantitative method for assessing bone morphology has been evolved. Microradiographs of thin sections of mandible have been scanned with a Joyce-Loebl double beam recording microdensitometer with a scanning autodensidater attachment, using a white beam. For each image the optical densities for all the pixels (picture elements) were divided into 10 groups. The limits of the division were fixed by the maximum and minimum densities occurring within the image. A computer generated map was produced which indicated the spatial distribution of the pixels within each group to which an arbitrarily chosen shading was attached. The number of pixels within each group is also shown on the map. The computer map was compared with the photomicrograph and, where necessary, the original section. The fractional area of hard tissue was then readily determined using the numerical values of each group of pixels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013239
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  • 19
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    Surface area of dental enamel, bone, and hydroxyapatite: Chemisorption from solution (1978)
    Springer
    Calcified tissue international 26 (1978), S. 139-142 
    Details
    ISSN: 1432-0827
    Keywords: Chemisorption ; Surface area ; Hydroxyapatite ; Bone ; Enamel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The surface areas of three different samples of hydroxyapatite, samples of deproteinized bone, and samples of whole and deproteinized enamel were determined by adsorption of an adduct (the diglycidyl ether of bisphenol A with N-phenylglycine) from methylene chloride solution. In all cases, the surface areas of these samples agree well with those obtained by the BET (N2) method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013248
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  • 20
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    The crystal sheaths from bivalve hinge ligaments (1978)
    Springer
    Calcified tissue international 25 (1978), S. 45-51 
    Details
    ISSN: 1432-0827
    Keywords: CaCO3 ; Amino acids ; Sheaths ; Ligament ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The aragonite crystals in the molluscan bivalve hinge ligament are surrounded by an organic sheath which is distinct from the remainder of the ligament matrix. Methods have been developed to isolate these sheathed crystals from the ligaments ofSpisula solidissima andMercenaria mercenaria employing a papain digestion of the matrix protein. The sheathed crystals fromSpisula have a CaCO3/protein ratio of 11.1 and those fromMercenaria a ratio of 29.6. The sheathed crystals and the empty crystal sheaths have been examined by electron microscopy for structural integrity. The sheath proteins exhibit much smaller proportions of the amino acids glycine and methionine than the hinge ligaments. These are characteristic amino acids of high concentration in the hinge ligaments of both species. The concentrations of acidic and basic amino acids are increased about two fold in the sheaths over those of the ligaments. Otherwise there is little similarity in the amino acid composition of the sheaths in the two species. However, SDS electrophoresis shows the sheaths of both to contain a major protein component with a molecular weight of about 25,000. The sheath protein from theMercenaria ligament contains about 5% carbohydrate and that ofSpisula sheaths less than 1% carbohydrate.
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    URL: http://dx.doi.org/10.1007/BF02010750
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    Effect of sex steroids on bone collagen synthesis in vitro (1978)
    Springer
    Calcified tissue international 25 (1978), S. 105-110 
    Details
    ISSN: 1432-0827
    Keywords: Progesterone ; 17β estradiol ; Testosterone ; Tissue culture ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Although sex steroids are known to affect skeletal metabolism, their effects on bone collagen synthesis have not been studied. We have examined the direct effects of progesterone, 17β estradiol, testosterone, 5α dihydrotestosterone and dehydroepiandrosterone on bone collagen and noncollagen protein synthesis in cultures of calvaria obtained from 21-day fetal rats. Bones were incubated for 24 to 168 h and3H-proline was added for the last 2 h of culture. Incorporation of the label into collagenase-digestible protein (CDP)1 and noncollagen protein (NCP) was determined using repurified bacterial collagenase. Progesterone caused a dose dependent inhibition of the labeling of CDP at concentrations of 3×10−7 M to 10−5 M after 96 h of culture. A smaller inhibitory effect was observed on NCP. The inhibitory effect was slow in onset and persisted when bones were incubated for 48 h with progesterone and then transferred to control medium for 48 h. Progesterone also inhibited the incorporation of3H-thymidine and3H-uridine into fetal rat calvaria. After 24 h of culture, 17β estradiol and testosterone had no effects on the labeling of CDP and NCP. After 96 h, 17β estradiol had a small and inconsistent stimulatory effect on the labeling of CDP but testosterone had no effect. Neither hormone altered the inhibitory effects of parathyroid hormone, cortisol and progesterone. Dihydrotestosterone and dehydroepiandrosterone had no effects after 24 h and 96 h of culture. 17β estradiol, testosterone and dihydrotestosterone did not affect the incorporation of3H-uridine or3H-thymidine into fetal rat calvaria. Our studies indicate that progesterone is an inhibitor of bone collagen synthesis and estrogens and androgens are not major regulators of bone formation in vitro.
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    URL: http://dx.doi.org/10.1007/BF02010758
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    The effect of growth retardation and of osteomalacia on the uptake of albumin by bone (1978)
    Springer
    Calcified tissue international 25 (1978), S. 29-35 
    Details
    ISSN: 1432-0827
    Keywords: Albumin ; Bone ; Growth retardation ; Osteomalacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary 125I-labeled rat albumin injected intravenously into rats was taken up by growing bone. Some of this radioactive albumin could be removed from bone by washing with saline, the proportion so removed decreasing from 82.5% at 1 day to 7.4% at 8 days. Both the total radioactivity, and that remaining in bone after saline wash, were reduced when growth was slowed by alteration or restriction of the diet. Although the amount of125I albumin in rachitic bone was reduced, autoradiography showed that radioactivity was present in rachitic osteoid. Immunoprecipitation using anti-rat-albumin serum showed that about half of the radioactivity released from normal bone by EDTA was still attached to albumin. These results suggest that albumin plays some part in the growth of bone.
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    URL: http://dx.doi.org/10.1007/BF02010748
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    X-ray diffraction and electron microscope study of osteons during calcification (1978)
    Springer
    Calcified tissue international 25 (1978), S. 133-143 
    Details
    ISSN: 1432-0827
    Keywords: Osteon ; X-Ray diffraction ; Electron microscopy ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To obtain information on the changes in the inorganic bone fraction during calcification, low- and wide-angle X-ray diffraction techniques and electron microscopy have been applied to single osteon samples. The samples were cylindrically shaped and their axes corresponded to the axes of the Haversian canals. The selection was made according to the degree of calcification and the orientation of collagen bundles and inorganic particles. Osteons at both the initial and final stages of calcification were chosen. Arrangements of fiber bundles and inorganic particles in successive lamellae characteristic of three types of osteon were selected, that is, longitudinally structured osteons, transversely structured osteons, and alternately structured osteons. The results indicate that in osteonic lamellar bone there are two types of inorganic particles: (1) granules arranged in linear or needle-shaped entities with maximum width 40–45 Å, which are regularly distributed at the level of the main band of the collagen fibrils where their maximum length reaches the length of the main band itself; that is, about 400 Å; and (2) very long crystallites, with a diameter of 40–45 Å, which grow with their crystallographicc-axis parallel to the collagen fibrils and cover much more than a major collagen period.
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    URL: http://dx.doi.org/10.1007/BF02010762
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    Isolation of lipopolysaccharides and the effect of Polymyxin B on the outer membrane of Corynebacterium autotrophicum (1978)
    Springer
    Archives of microbiology 118 (1978), S. 67-69 
    Details
    ISSN: 1432-072X
    Keywords: Corynebacterium autotrophicum ; Outer Membrane ; Lipopolysaccharides ; Biochemical analysis ; Polymyxin B ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lipopolysaccharides (LPS) from Corynebacterium autotrophicum were isolated and analyzed. Autotrophically grown cells contained 2–5 mg of partly purified LPS per g dry weight of lyophilized cells. Serological cross reaction with Lipid A antigen of Salmonella minnesota confirmed the presence of LPS in C. autotrophicum. Electron microscopy of negatively stained Polymyxin B-treated cells showed formation of blebs on the Outer Membrane indicating an interaction of Polymyxin B specifically with LPS. Up to now, no Gram-positive organisms are known which contain any LPS. Thus, C. autotrophicum, though giving opposite results when the Gram-staining reaction was applied by several authors, has to be classified into the group of Gram-negative bacteria.
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    URL: http://dx.doi.org/10.1007/BF00406076
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    Characteristics of a cholera phage (1978)
    Springer
    Archives of microbiology 119 (1978), S. 303-304 
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    ISSN: 1432-072X
    Keywords: Vibrio cholera phage group II ; Properties ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The basic physical, chemical and physiological properties of a group II cholera phage belonging to Mukerjee's classification has been described.
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    URL: http://dx.doi.org/10.1007/BF00405410
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    Detection of small cryptic plasmids in Salmonella typhimurium strain LT2 (1978)
    Springer
    Archives of microbiology 119 (1978), S. 87-90 
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    ISSN: 1432-072X
    Keywords: Salmonella typhimurium strain LT2 (ColIb) ; Cryptic plasmids ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Small cryptic plasmids of molecular weights ranging from 1 to 3 Mdal were detected by electron microscopy in Salmonella typhimurium strain LT2 (ColIb). They were divided into different size classes. Two of the cryptic plasmids were transferred simultaneously with ColIb to Escherichia coli.
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    Electron microscopy of the cell wall complex ofMethylomonas albus (1978)
    Springer
    Archives of microbiology 119 (1978), S. 227-229 
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    ISSN: 1432-072X
    Keywords: Cell wall ; Electron microscopy ; Methylomonas albus ; Goblet sub-units
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In surface view, the cell wall complex ofMethylomonas albus possesses a hexagonal pattern of ridges. Thin sections reveal a continuous layer of goblet-shaped elements attached to the outermost surface of the lipopolysaccharide membrane. A possible interpretation of the cell wall complex ofM. albus, based on the fine-structural data is presented.
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    URL: http://dx.doi.org/10.1007/BF00964278
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    Ultrastructure of carotenoid mutant strain R-26 of Rhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 118 (1978), S. 305-308 
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    ISSN: 1432-072X
    Keywords: Carotenoid mutant strain R-26-Rhodopseudomonas sphaeroides ; Electron microscopy ; Intracellular membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stained thin-sections and freeze-fractured preparations of the carotenoid-less mutant strain R-26 of Rhodopseudomonas sphaeroides grown photosynthetically revealed 2 morphological kinds of intracellular membrane systems- spherical vesicles distributed throughout the cytoplasm and lamellae confined to the periphery of the cell. The lamellar membranes appeared to be large, flattened vesicles.
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    URL: http://dx.doi.org/10.1007/BF00429122
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    Calcium uptake and survival of Bacillus stearothermophilus (1978)
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    Archives of microbiology 119 (1978), S. 17-24 
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    ISSN: 1432-072X
    Keywords: Thermophilic bacteria ; Bacillus stearothermophilus ; thermostability ; Calcium ; Transport ; Survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The calcium transport in resting vegetative cells of Bacillus stearothermophilus was studied by determining the retention of 45Ca in a membrane filter assay. The kinetics of death by vegetative cells, when suspended in buffer at 55°C, was also investigated. The calcium influx required the presence of an energy source, e.g. glucose-1-phosphate and the system exhibited saturation kinetics. The requirements for survival of the thermophilic cells reflected those of the calcium transport system. Thus, cells treated with nitrogen gas showed an increased thermal stability and a decreased efflux of calcium. The initial velocity of calcium influx correlated linearly with the survival of the cells after 1 min heating at 55° C. Lanthanum inhibited calcium influx and reduced survival. Magnesium did not inhibit calcium influx but could replace calcium as a stabilizing agent. The results suggest that the thermophilic cells are not intrinsically heat stable but survive due to a high cellular concentration of divalent ions.
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    URL: http://dx.doi.org/10.1007/BF00407922
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    Development and ultrastructure of the marine, parasitic oomycete, Lagenisma coscinodisci Drebes (Lagenidiales) (1978)
    Springer
    Archives of microbiology 116 (1978), S. 133-139 
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    ISSN: 1432-072X
    Keywords: Lagenisma ; Coscinodiscus ; Infection ; Endosymbiotic bacteria ; Tip growth ; Wall-less thallus ; Host-parasite interface ; Membranes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lagenisma coscinodisci is diplanetic and has two different cyst stages. The secondary cyst has a uniform cell wall of fibrillar material. It attaches to a Coscinodiscus frustule and germinates with an infection tube. The cyst becomes filled with an enlarging expulsion vacuole. The infection tube penetrates the diatom cell between the cingula. Inside the host cell the fungus grows as an irregularly branched wall-less thallus. In the hyphae apical vesicles are lacking. The infection tube is plugged by wall material. There are no microtubules which might participate in the morphogenesis of the thallus. The plasmalemma of the diatom is pushed inward but not pierced by the fungus. Along the host-parasite interface it lies closely paralled to the Lagenisma plasmalemma which is extremely straight here and measures about 10 nm instead of about 5–6 nm at the surfaces of other stages. The Coscinodiscus plasmalemma disintegrates at about the same time when the cytoplasm breaks down. The fungus allows bacteria to enter the diatom; there are also endosymbiontic bacteria in unattacked cells — The growth mechanisms are discussed and the host-parasite interface is compared with that of other fungi.
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    A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule (1978)
    Springer
    Cell & tissue research 186 (1978), S. 121-133 
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    ISSN: 1432-0878
    Keywords: Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
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    URL: http://dx.doi.org/10.1007/BF00219659
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    Ultrastructure of the theca interna of ovarian follicles in sheep (1978)
    Springer
    Cell & tissue research 187 (1978), S. 457-472 
    Details
    ISSN: 1432-0878
    Keywords: Ovarian follicles (sheep) ; Theca interna ; Oestrogen ; Androgen ; Capillaries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The theca interna of non-atretic ovarian follicles from 2.0 mm in diameter up to the stage shortly following ovulation was studied by light and electron microscopy. In follicles 〈3.0mm in diameter, the theca interna consisted of about 8–12 layers of flattened cells, together with many capillaries and small bundles of collagen. Two main forms of cellular differentiation were seen. These were towards either fibroblast-like cells or presumed steroidogenic cells whose cytoplasm contained large amounts of predominantly smooth tubular endoplasmic reticulum, to which some ribosomes were attached. The majority of cells were of relatively undifferentiated or intermediate structure. In larger follicles up to the early stages of oestrus the theca interna cells became larger and less flattened, and cells rich in tubular endoplasmic reticulum became proportionately more numerous. By 18 h after the onset of oestrus the theca interna was oedematous, and many cells possessed pseudopodia. Many cells also contained numerous lipid droplets, but there were no signs of thecal cell degeneration or death. Shortly after ovulation the basal lamina of the membrana granulosa was incomplete, and it became more difficult to distinguish between theca and granulosa layers. Structural heterogeneity, with two major cell types and cells of intermediate structure, was present at all stages. It was concluded that: (1) the theca interna of 2.0–2.9 mm follicles contained many cells whose structure was compatible with a steroidogenic capacity; (2) changes in the differentiated thecal cells up to the early stages of oestrus were quantitative rather than qualitative, and suggestive of an increased steroidogenic capacity; (3) the accumulation of lipid in many cells of the theca interna by 18 h after the onset of oestrus probably reflected a reduction in steroidogenic activity; and (4) there was no evidence of any structural specialization to facilitate the transport of steroids from the theca interna to the membrana granulosa.
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    URL: http://dx.doi.org/10.1007/BF00229610
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    Local degenerative changes in the drum muscles of piranhas (Serrasalminae, Characidae) (1978)
    Springer
    Cell & tissue research 188 (1978), S. 75-82 
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    ISSN: 1432-0878
    Keywords: Drum muscles ; Piranha ; Degenerative changes ; Fine structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the posterior drum muscle of the piranha structural alterations are frequently observed. Electron microscopic studies revealed a disordering of the myofibrils in these regions, accompanied by conspicuous changes in the mitochondria. As the degree of disorder increases, the mitochondrial cristae initially swell to form vesicles. Eventually the mitochondria become filled with myelin-like lamellar structures, which in many cases coalesce to form a dense outer wall. A striking concentration of lysosomes into localized masses was also characteristic of these regions.
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    URL: http://dx.doi.org/10.1007/BF00220515
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    Studies on the ultrastructure of the integument of the rotifer Habrotrocha rosa Donner (Aschelminthes) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 167-177 
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    ISSN: 1432-0878
    Keywords: Hypodermis ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The integument of the rotifer Habrotrocha rosa Donner is provided with pores and formed by an extrasyncytial cuticle and a syncytial hypodermis. The hypodermis peripherally contains 3 layers of dense cytoplasm and borders the cuticle by an asymmetric cell membrane. The wall of the pores is stiffened proximally like an annulus. The pores lead into cytoplasmic invaginations which are surrounded by vesicles. Close to and also beneath the condensed cytoplasmic layers microbodies are found, which are interpreted as microperoxisomes. Subhypodermal layers of muscles are connected with the cytoplasm of the hypodermis by desmosome-like structures.
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    URL: http://dx.doi.org/10.1007/BF00223127
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    Catecholaminergic innervation of muscles in the hindgut of crustaceans (1978)
    Springer
    Cell & tissue research 189 (1978), S. 257-266 
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    ISSN: 1432-0878
    Keywords: Neuromuscular junction ; Hindgut ; Crustacea ; Catecholamine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80–110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.
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    URL: http://dx.doi.org/10.1007/BF00209275
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    Influence of maternal adrenalectomy on the ultrastructure of the adrenal gland in neonatal rats (1978)
    Springer
    Cell & tissue research 189 (1978), S. 277-286 
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    ISSN: 1432-0878
    Keywords: Maternal adrenalectomy ; Rat ; Influence on the adrenals of newborn animals ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Maternal adrenalectomy at 7 or 14 days of gestation produced increased cell necrosis within zona reticularis cells on the day of birth and at 24 or 48 h after birth. Small remnants or large portions of adrenocortical cells were present within macrophages. In otherwise normal adrenocortical cells, lipid droplets were incorporated within some mitochondria. Autophagocytosis of single mitochondria was observed within adrenocortical cells. Undoubtedly ultrastructural changes represent stimulation of adrenocortical cells in neonatal rats in response to maternal adrenalectomy.
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    URL: http://dx.doi.org/10.1007/BF00209277
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    Structure of occluding junctions in ileal epithelial cells of suckling rats (1978)
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    Cell & tissue research 191 (1978), S. 449-462 
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    ISSN: 1432-0878
    Keywords: Ileum (Rat) ; Occluding junctions ; Freeze-fracture ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two kinds of occluding junctions are found between ileal epithelial cells of suckling rats: apical zonulae occludentes (ZO) and fasciae occludentes (FO) which are associated with the lateral plasma membranes of many epithelial cells. In unfixed preparations, glycerol treatment induces the further proliferation of extensive fasciae occludentes. Both kinds of junction have identical structural elements when visualized in freeze fracture replicas, although the arrangement of these elements differs. Zonulae occludentes consist of networks of branching and anastomosing linear ridges or rows of ∼10 nm particles with 20–30 nm spaces between the rows which form narrow belt-like structures around the apical region of adjacent cells. Fasciae occludentes, on the other hand, consist of similar linear ridges or rows of particles but the junction strands are often discontinuous, open ended and only occasionally intersect with each other. Several different fracture planes through the plasma membrane in the region of the occluding junctions have been observed and these provide further evidence that two components, one from each membrane, fused at the level of the extracellular space, form the junction sealing element. Furthermore, we present evidence which indicates a staggered rather than an in-register arrangement of these two components.
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    The ultrastructure of the accessory sex organs of the male rat (1978)
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    Cell & tissue research 192 (1978), S. 39-51 
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    ISSN: 1432-0878
    Keywords: Prostate ; Rat-Anti-Androgens ; Nuclear alterations ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the nuclei of epithelial cells of the dorsal lobe of the rat prostate were studied after administration of three different antiandrogenic compounds. The nucleolus appears to undergo a progressive disorganisation with partial fragmentation and dispersion of its normal components. Different types of intranuclear inclusions were found. The various alterations observed were often encountered within the same section. This may indicate that the nuclear alterations occur in the same compartment of the cell, and represent a dysfunction of integrated biochemical events occurring within this compartment. The findings support a view that the stimulatory secretory effect of androgens is mediated via a ‘secretory center’, located within the nucleolusassociated chromatin. Within this ‘secretory center’, the initial steps of the secretory process, the binding of the DHT receptor complex to DNA is assumed to occur.
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    URL: http://dx.doi.org/10.1007/BF00231021
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    Stereological model system for free cells and base-line data for human peripheral blood-derived small t-lymphocytes (1978)
    Springer
    Cell & tissue research 192 (1978), S. 121-142 
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    ISSN: 1432-0878
    Keywords: T-lymphocytes ; Stereological model system ; Free cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Menschliche, in Nylonwolle gereinigte T-Lymphozyten aus dem peripheren Blut dienten als repräsentatives Untersuchungsobjekt zur Schaffung eines neuen stereologischen Modellsystems für freie, sphärische Zellen. Dieses System erlaubt, die Zelle und die darin enthaltenen Strukturkomponenten auf ultrastruktureller Ebene quantitativ zu charakterisieren.
    Notes: Summary T-lymphocytes derived from human peripheral blood and passed through a nylon-wool column, were employed to develop and test a new Stereological model system for free spherical cells, allowing a quantitative characterization of the cell and its components at the ultrastructural level. Electron micrographs were recorded in a hierarchical manner at three different levels of magnification and subjected to point counting procedures. The resulting parameters were expressed in relation to various reference compartments, both absolute and relative. Results indicated that the average volume of a small, non-activated T-lymphocyte was 103.8 μm3, the nuclear volume 47.5 μm3 and the cytoplasmic volume 55.9 μm3. On the average, the cytoplasm contained 30 mitochondria, 0.7 μm3 RER-cisternae, 0.2 μm3 cisternae and vesicles of the Golgi apparatus and about 231,000 free ribosomes (most of them single). The ratio of eu- to heterochromatin volume was 0.5. The design and application of the Stereological model system are discussed with regard to dynamic studies of a variety of free cells, such as macrophages, neutrophilic granulocytes and various lymphocytes.
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    An autoradiographic study of satellite cell differentiation into regenerating myotubes following transplantation of muscles in young rats (1978)
    Springer
    Cell & tissue research 186 (1978), S. 535-540 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Satellite cells ; Regeneration ; Electron microscopy ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Satellite cells were traced autoradiographically during the regeneration of skeletal muscle in young Sprague-Dawley rats. Approximately 31% of the satellite cells in uninjured muscles appeared labelled after three injections of tritiated thymidine; none of the myonuclei were labelled in the same muscles. Four to six days after transplanting the radioactive muscles to non-radioactive littermates, regenerating myotube nuclei in the host appeared labelled. Thus, this study confirms that satellite cells in young rats can differentiate into multinucleated myotubes following muscle injury.
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    URL: http://dx.doi.org/10.1007/BF00224941
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    Endocrine cells in the gut of the ascidian Styela clava (1978)
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    Cell & tissue research 187 (1978), S. 159-165 
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    ISSN: 1432-0878
    Keywords: Endocrine cells ; Ascidian (Styela clava) ; Gut epithelium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies have shown the presence of two types of granulated endocrine cell in the gut of Styela clava. Type I, which occurs in the stomach and intestine contains small irregular granules, each with a distinct halo. Type II, found only in the oesophagus contains larger rounded granules, often with little or no halo. The characteristics of these two cell types are compared with those of endocrine cells found in the digestive tracts of other protochordates and discussed with special reference to the evolution of gastrointestinal endocrine cells in vertebrates.
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    URL: http://dx.doi.org/10.1007/BF00220628
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    The junctional connections between the cells of the urinary bladder in the rat (1978)
    Springer
    Cell & tissue research 187 (1978), S. 439-448 
    Details
    ISSN: 1432-0878
    Keywords: Urinary bladder epithelium (Rat) ; Gap junctions ; Tight junctions ; Electron microscopy ; Freeze-fracturing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The junctional connections between the cells of the urinary bladder epithelium in rat have been studied by freeze-fracturing. Tight junctions and desmosomes are known as structural features of the epithelium. In addition, gap junctions (nexus) have been found to connect the epithelial cells in an irregular distribution pattern. The junction size ranges from few assembled particles up to plaques with irregular forms. This may indicate that the gap junctions are mobile structures. The functional significance of the junctions in comparison with electrophysiological data is discussed.
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    URL: http://dx.doi.org/10.1007/BF00229608
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    The passage of spermatozoa through the vitelline membrane in the domestic fowl, Gallus gallus (1978)
    Springer
    Cell & tissue research 188 (1978), S. 497-508 
    Details
    ISSN: 1432-0878
    Keywords: Fertilization ; Domestic fowl ; Acrosome reaction ; Vitelline membrane ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developing outer layer of the vitelline membrane of the ovum in the posterior part of the infundibulum of the domestic fowl contains many spermatozoa in nearly parallel orientation with its inner layer. When the acrosomal region of a spermatozoon approaches or contacts the inner layer, promptly undergoes the acrosome reaction. The outer acrosomal membrane and overlying plasma membrane fuse together and the apical region of the acrosome opens, so that the acrosomal contents are released. Meanwhile the spermatozoon remains a time in contact with the surface of the inner layer, and the network of the inner layer just under the tip of the sperm head begins to be dissolved. This dissolution extends downward forming a tunnel, approximately 9 μm in diameter. The spermatozoon then passes through the inner layer obliquely via the central region of the tunnel and arrives at the perivitelline space.
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    URL: http://dx.doi.org/10.1007/BF00219787
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    A study of the fine structure of the pit organ of the common Japanese sea eel Conger myriaster (1978)
    Springer
    Cell & tissue research 189 (1978), S. 375-388 
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    ISSN: 1432-0878
    Keywords: Lateral line organ ; Pit organ ; Sea eel (Conger myriaster) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the pit organ of the sea eel has been studied by means of electron microscopy. The sensory epithelium of the pit organ consists of sensory cells and supporting cells. The apical surface of the sensory cell is studded with sensory hairs consisting of a kinocilium and stereocilia. The sensory cells are divided into two groups. In one, the kinocilium points dorsally and in the other the kinocilium points ventrally. The total number of sensory cells in one pit organ is about 100, and the ratio of cells with opposite polarity is about 1∶1. On the basis of these structural features, the pit organ is considered to be a mechano-receptor sensitive to the movement of liquid in a dorso-ventral direction. It may also serve as an ion receptor, sensitive to environmental ion concentration. Efferent nerve terminals make rare synaptic contacts on the afferent nerve fiber.
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    URL: http://dx.doi.org/10.1007/BF00209127
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    On the excretory system of the rotifer Habrotrocha rosa donner (1978)
    Springer
    Cell & tissue research 189 (1978), S. 515-523 
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    ISSN: 1432-0878
    Keywords: Protonephridium ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The excretory system of Habrotrocha rosa consists of two protonephridia. From each of them seven tubules lead to a terminal organ, also called cyrtocyte. Its weir basket contains structures which resemble ciliary rootlets. The lumen of the excretory system is bordered by a syncytial layer of cytoplasm. Cells are only found in the upper region of the trunk, where the channel is twisted several times.
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    URL: http://dx.doi.org/10.1007/BF00209137
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    Studies on the ultrastructure of the rotifer Habrotrocha rosa Donner (Aschelminthes) (1978)
    Springer
    Cell & tissue research 189 (1978), S. 525-535 
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    ISSN: 1432-0878
    Keywords: Alimentary system ; Rotifer ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The alimentary system of Habrotrocha rosa is composed of the alimentary channel, five digestive glands and another gland which is in close relation to the intestinal syncytium. After the present investigation, the alimentary channel can be divided into sections which clearly differ from each other, these are: oral cavity, pharynx, oesophagus, mastax, stomach-hose, syncytium of intestine, and terminal intestine.
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    URL: http://dx.doi.org/10.1007/BF00209138
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    Nerve-purkinje fiber relationship in the moderator band of bovine and caprine heart (1978)
    Springer
    Cell & tissue research 188 (1978), S. 11-18 
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    ISSN: 1432-0878
    Keywords: Purkinje fibers (Ox, goat) ; Axons ; Nerve endings ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The moderator band in the heart of the ox and goat contains bundles of Purkinje fibers and nerve fibers separated by connective tissue. The axons are mostly unmyelinated and embedded in the cytoplasm of Schwann cells. Small bundles of axons run close to the Purkinje fibers. The axons dilate into varicosities 0.5 to 1.6 μ in diameter (mean 0.95 μ), containing three types of vesicles: 1) agranular vesicles with a diameter of 400–500 Å, 2) large dense-cored vesicles with a diameter of 800–1200 Å, 3) small dense-cored vesicles with a diameter of 500 Å. Most varicosities contain agranular vesicles together with a few large dense-cored vesicles. The gap between the varicosities and the nearest Purkinje fiber is unusually wide and normally varies between 0.3 μ and 0.8 μ. No intimate nerve-Purkinje fiber contacts, with a cleft of 200 Å, were observed.
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    URL: http://dx.doi.org/10.1007/BF00220511
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    On T-tubule openings at the sarcolemma of white fast-twitch muscle fibres in fish and frog (1978)
    Springer
    Cell & tissue research 188 (1978), S. 265-272 
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    ISSN: 1432-0878
    Keywords: Muscles ; T-system ; Fish ; Frog ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In “white” muscle fibres of a teleost fish T-tubule openings may occur regularly at all Z-disc levels between adjacent peripheral myofibrils, the T-tubule openings thus occurring at a density of ca. 0.9 μm-2. In frog “white” fibres, T-tubule openings are infrequently seen in material fixed like the fish material. In material prepared according to the albumin method of Gray (1975, 1976 a, b) which renders the muscle fibres swollen, straight tubules or sometimes chains of vesicles instead are seen opening at the sarcolemmal surface. Such tubules occur at a higher density than expected from experiments with local activation of contraction. Lability and dynamics within the T-system normally and during fixation are discussed.
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    URL: http://dx.doi.org/10.1007/BF00222636
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    Parenchymal fine structure of the subfornical organ in the Japanese quail, Coturnix coturnix japonica (1978)
    Springer
    Cell & tissue research 191 (1978), S. 405-419 
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    ISSN: 1432-0878
    Keywords: Subfornical organ ; Japanese quail, Coturnix coturnix japonica ; Monoaminergic innervation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parenchyma of the subfornical organ (SFO) of the Japanese quail was studied by light and electron microscopy. The SFO consists of ependymal, intermediate, and basal (perimeningeal) layers. In the intermediate layer, neurons, glial cells, and their processes are found. Axons containing dense core granules approximately 80 nm in diameter are numerous, some of which make synaptic contact with the neuronal perikarya or dendrites. Synaptic vesicles in some axons contain a dense dot in the interior after treatment with 5-hydroxydopamine. The activity of the SFO, which is probably concerned with elicitation of drinking by angiotensin II, may be regulated at least partly by afferent monoaminergic axons. Capillaries with a non-fenestrated endothelium are occasionally found in the parenchyma. The basal layer is occupied by glial processes abutting on the digitating layer of perivascular connective tissue of meningeal vessels. The endothelium of these vessels is occasionally fenestrated. Trypan blue injected systemically accumulated in the SFO, but not in the deeper areas of the brain. The absence of a blood-brain barrier is suggested in the SFO.
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    URL: http://dx.doi.org/10.1007/BF00219805
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    Catharanthine: A novel stimulator of pancreatic enzyme release (1978)
    Springer
    Cell & tissue research 192 (1978), S. 277-284 
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    ISSN: 1432-0878
    Keywords: Pancreas ; Calcium ; Vinca alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plant alkaloid, catharanthine, was shown to stimulate release of amylase from pancreatic fragments and to cause extensive degranulation of pancreatic acinar cells with accumulation of membrane material in the Golgi region. The extent and time course of maximal catharanthine stimulation was comparable to that induced by the cholinergic analog bethanechol. Antimycin inhibited the action of catharanthine while atropine did not. Removal of Ca2+ from the incubation medium inhibited amylase release induced by catharanthine but did not affect release induced by bethanechol. Catharanthine induced a delayed release of 45Ca2+ from prelabeled pancreatic fragments as compared to bethanechol. It is suggested therefore that catharanthine activates the physiological pathway controlling amylase release by causing a rise in cytoplasmic Ca2+ but the mechanism by which this occurs is different from that caused by physiological secretagogues.
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    Sequential differentiation of intestinal endocrine cells in the fetal mouse (1978)
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    Cell & tissue research 192 (1978), S. 267-276 
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    ISSN: 1432-0878
    Keywords: Endocrine glands ; Mouse small intestine ; Mouse embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The duodenum and ileum of 15 to 18-day old Swiss ICR mouse embryos were studied with the electron microscope to follow the differentiation of endocrine cells. Endocrine cells were classified on purely morphological characteristics. EC cells appeared at 16 days of gestation in both segments. At the same stage G cells were seen in the duodenum and K cells in the ileum. ECL, and S cells were identified in the duodenum at 17 days. Finally, D cells were seen at 18 days of gestation in the duodenum and ileum. With the electron microscope, endocrine cells were not identified in the small intestine of the mouse before the formation of villi.
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    The myelination of the cerebellar cortex in the cat (1978)
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    Cell & tissue research 188 (1978), S. 509-520 
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    ISSN: 1432-0878
    Keywords: Cerebellar cortex (Cat) ; Postnatal development ; Myelination of efferent and afferent fiber systems ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The myelination of the cerebellar cortex of the cat was investigated in 61 cats aged from 3 hrs post partum to two and a half years. The first myelinated fibers appear at the time of birth in the central medullary ray. Before the onset of myelination, all fibers reach a critical diameter of about 1 μm. About the 14th day of life the number of oligodendrocytes in the prospective white matter increases markedly. Thereafter, the oligodendrocytes invade the inner granular layer. It therefore seems that the myelination of the cerebellar cortex proceeds from the central medullary ray towards the granular layer. At the 60th day of postnatal life, most of the afferent and efferent fiber systems are myelinated. These findings are discussed in relation to the development of function and the maturation of the electrical activity of the cerebellar circuit.
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    The interstitial cells in the renal medulla of rat, rabbit, and gerbil in different states of diuresis (1978)
    Springer
    Cell & tissue research 189 (1978), S. 1-18 
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    ISSN: 1432-0878
    Keywords: Kidney medulla ; Rat, rabbit, gerbil ; Interstitial cells ; Lipid droplets ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inner zone of the renal medulla of rats, gerbils, and rabbits was investigated to determine whether or not there are any characteristic ultrastructural differences between the interstitial cells of these species. The effects on the interstitial cells of water deprivation and water loading were also investigated. In all three species, the Type 1 interstitial cells, the lipid containing cells, were abundant and their distribution and topographical relations as well as their general ultrastructure were similar. The previously reported significantly higher frequency in desert rats could not be confirmed. Although the lipid droplets of the interstitial cells were smaller in gerbils and rabbits when compared to rats, their fine structure was similar. Their electron dense outer zone was sometimes associated with a granular material and/or a lamellar material with a periodicity of about 40 Å resembling phospholipid “myelin figures”. Water-loaded rats showed a considerable increase in the number of lipid droplets when compared to dehydrated or untreated animals. In contrast, the interstitial cells of waterloaded gerbils and rabbits were depleted of lipid droplets.
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    URL: http://dx.doi.org/10.1007/BF00223117
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    Chrysosphaerella (Pseudochrysosphaerella)solitaria, spec. nova (Chrysophyceae) (1978)
    Springer
    Plant systematics and evolution 129 (1978), S. 135-142 
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    ISSN: 1615-6110
    Keywords: Algae ; Chrysophyceae ; Chrysosphaerella solitaria ; Electron microscopy ; phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new unicellular species of the genusChrysosphaerella (Chrysophyceae) was found in fresh-water ponds in Switzerland, Japan, and the U.S.A. It is described asC. solitaria. The genus is divided into two subgenera:Chrysosphaerella, comprising the colonial species, andPseudochrysosphaerella, the unicellular ones.
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    Fine structure and metabolic adaptation of red and white muscles in tuna (1978)
    Springer
    Environmental biology of fishes 3 (1978), S. 185-191 
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    ISSN: 1573-5133
    Keywords: Euthynnus affinis ; Electron microscopy ; Kawakawa tuna ; Red fibres ; White fibres ; Muscle size ; Activity ; Thermogenesis ; Thermal inertia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis An electron microscopic study of the red and white muscle fibres in the trunk musculature of the Kawakawa tuna (Euthynnus affinis) was carried out with a view to correlating their structure with metabolic adaptation. The red fibres which are considerably smaller in diameter (34.58 μm ± 6.16 S.D.) are characterized by their high content of myoglobin, mitochondria, lipid droplets and glycogen granules. The white fibres which are relatively larger in diameter (66.03 μm ± 11.59 S.D.) are characterized by their lack of myoglobin, low mitochondria) density, high content of glycogen granules and the conspicuous absence of lipid droplets. The characteristics in fine structure of the two fibre types are discussed in the light of their metabolic adaptation, the red fibres as being adapted for long term cruising movement utilizing lipid as the main source of energy and the white fibres for short bursts of activity metabolizing glycogen as the chief fuel. The tuna, with the acquisition of the counter-current heat exchange system which provides for the retention of the heat generated from high substrate oxidation in the red muscle and an efficient respiratory system, it is postulated, is well adapted for high speed sustained swimming.
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    URL: http://dx.doi.org/10.1007/BF00691942
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    Role of zinc and calcium in the formation and storage of insulin in the pancreatic β-cell (1978)
    Springer
    Cell & tissue research 188 (1978), S. 107-118 
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    ISSN: 1432-0878
    Keywords: Pancreatic β-cells (mouse) ; Formation and storage of insulin ; Role of zinc and calcium ; Culture of islets ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The effects of culture of isolated mouse islets of Langerhans for up to 9 days in media which had been depleted of zinc electrochemically or with the chelating agent Tris-(2-aminoethyl) amine, or of calcium, have been compared. 2. An 83% reduction of extracellular zinc concentration did not adversely affect proinsulin biosynthesis, conversion of proinsulin to insulin, or the ability of cells to store newly formed insulin in granules. When incubation media were depleted of both zinc and calcium the β-cells produced abnormally large electron-lucent granules, consistent with the failure of insulin to crystallise within the granule sac. 3. Very similar results, with formation of large electron lucent granules, were obtained after culture of islets in the absence of calcium but in the presence of normal concentrations of zinc. 4. It is suggested that zinc may play a less critical role in the biosynthesis of proinsulin and its conversion to insulin, while calcium may have a more important function in insulin storage, than has sometimes previously been supposed.
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    Penetration of spermatozoon into the ovum and transformation of the sperm nucleus into the male pronucleus in the domestic fowl, Gallus gallus (1978)
    Springer
    Cell & tissue research 190 (1978), S. 89-98 
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    ISSN: 1432-0878
    Keywords: Fertilization ; Membrane fusion ; Male pronucleus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The apex of the sperm head which has undergone the acrosome reaction comes in contact with the plasma membrane of the ovum. After the entire surface of the inner acrosomal membrane has come into close contact with the plasma membrane of the ovum, the two membranes fuse to form a continuous membrane. All parts of the spermatozoon that are devoid of plasma membrane penetrate into the ooplasm. As the head of the spermatozoon moves deeper into the ooplasm, the chromatin begins to disperse, and the head of spermatozoon is transformed into a large spherical nucleus with low electron density. At a later stage of the transformation, many small vesicles appear around the nucleus and subsequently fuse to form two continuous membranes. These membranes represent the male pronuclear envelope. The condensation of the chromatin occurs in places in the nucleus, so that the male pronucleus is formed. During the course of the formation of the male pronucleus, the subacrosomal rod and tail become detached from the head and disintegrate.
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    On the ampullary organs of the South-American paddle-fish Sorubim lima (Siluroidea, Pimelodidae) (1978)
    Springer
    Cell & tissue research 190 (1978), S. 357-369 
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    ISSN: 1432-0878
    Keywords: Ampullary organs ; Siluroidea ; Sensory cells ; Synaptic junctions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ampullary organs were found in the epidermis of the paddle-fish Sorubim lima; they are distributed all over the skin surface of the fish but are particularly densely grouped in the head region and on the dorsal surface of the paddle. Histological and electron microscopical observations show that their structure is similar to the type of cutaneous ampullary organs characteristic of other Siluroidea. Composed of a relatively large mucus-filled ampulla, the organ possesses a short and narrow canal which leads to the outer epidermal surface. The wall of the ampulla is formed of several layers of flat epidermal cells. In general four sensory cells, each one surrounded by supporting cells, compose the sensory epithelium at the bottom of the ampulla. The inner surface of the sensory cells in contact with the ampullary mucus bears only microvilli. The contact between the nerve endings and the sensory cells show the characteristic structure of an afferent neuro-sensory junction. Two ampullae are innervated in some cases by the same afferent nerve fibre.
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    The ultrastructure of the male and female prostate of Praomys (Mastomys) natalensis (1978)
    Springer
    Cell & tissue research 190 (1978), S. 539-552 
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    ISSN: 1432-0878
    Keywords: Prostate ; Praomys natalensis ; Castration ; Changes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Male ventral and female prostates of Praomys (Mastomys) natalensis were examined with the electron microscope. The findings support and add to information obtained with the light microscope on tissues from normal, castrated and ovariectomised animals. Our results indicate that although the female prostate may be considered a homologue of the male ventral prostate anatomically and histologically, there are differences in sub-cellular morphology and hormone dependence. Cells of the intact ventral prostate of the male are characterised by prominent dilated Golgi vesicles and electron-dense “mature secretory granules” seen in the apical region of the cell. In the cells of the female prostate these features are absent. These morphological differences reflect the influence of hormones upon the cells, as shown by the reduction of the dilated Golgi vesicles in the castrated male and conversely, their occasional presence in the cells of the oestrous female. Comparison of castrated and ovariectomised animals shows that the male ventral prostate is much more dependent on androgens than the female is on ovarian hormones. There are several modes of secretion in the male ventral and the female prostate. These are by acellular and cellular blebbing, by a variety of secretory vesicles into the acinar lumina, and by a system of “double walled” vesicles not previously described.
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    On the chromaffin cells in dog adrenal medulla; with special reference to the small granule chromaffin cells (SGC cells) (1978)
    Springer
    Cell & tissue research 191 (1978), S. 1-14 
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    ISSN: 1432-0878
    Keywords: Adrenal medulla ; Dog ; SGC cell ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Small granule chromaffin cells (SGC cells) were identified in the adrenal medulla of adult dogs. They were small in size and usually showed a high nucleo-cytoplasmic ratio. Cytoplasmic projections were occasionally observed in some of these cells. They contained a variable number of small secretory granules with diameters ranging from 70 to 300 nm, but mostly from 100 to 200 nm. The densities of the secretory granules were variable, ranging from highly dense to less dense. These adrenal SGC cells were rich in free ribosomes and polysomes, but were relatively poor in other cell organelles. Chromaffin cells which were intermediate in their characteristics (IM cells) between the SGC cells and the typical A and N cells were also identified. These IM cells contained both highly electron dense and less dense granules in various proportions. The IM cells were classified into two subgroups, according to the proportions of adrenaline type granules and noradrenaline type granules. One group resembled A cells (IM-A cells) and the other resembled N cells (IM-N cells). Light microscopic histochemical studies of A cells stained with the ammoniacal silver solution demonstrated that they contained a small number of darkly stained granules. Electron microscopic cytochemistry revealed that the electron dense granules in the SGC cells, IM cells and A cells reacted positively with both the potassium dichromate solution at pH 4.1 and the ammoniacal silver solution.
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    The spermatozoon of Oikopleura dioica Fol (Larvacea, Tunicata) (1978)
    Springer
    Cell & tissue research 191 (1978), S. 27-37 
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    ISSN: 1432-0878
    Keywords: Spermatozoon ; Oikopleura dioica ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The spermatozoon of Oikopleura dioica is about 30 μm long, with a spherical head, about 1 μm wide, a 3 μm long and 1 μm wide midpiece, and a 25 μm long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 μm3. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.
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    Effects of systemic administration of 6-hydroxydopamine on the circumventricular organs in nonhuman primates (1978)
    Springer
    Cell & tissue research 191 (1978), S. 141-150 
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    ISSN: 1432-0878
    Keywords: Subfornical organ ; Third ventricle ; 6-Hydroxydopamine ; Electron microscopy ; Primate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurotoxin 6-hydroxydopamine (6-OH-DA) has been shown to produces degenerative changes in noradrenergic nerve terminals and preterminals in the CNS following intracisternal, intraventricular, and stereotaxic injection into the brain parenchyma. Systemic injections of this drug are also known to result in degenerative changes in noradrenergic terminals in the peripheral nervous system and in the circumventricular organs (CVO; areas of the CNS which lie outside the blood brain barrier). In the present study eight adult female cynomolgus monkeys were employed. The four experimental animals were injected on two successive days with 150 and 200 mg/kg 6-OH-DA, respectively. The four controls received only the diluent consisting of 0.1% ascorbic acid in normal saline. Two animals from each of the experimental and control groups were sacrificed at 2 h and 24 h after the second injection. Degenerative changes in the SFO neurons were characterized by a generalized increase in electron density of cytoplasmic elements in axonal terminals and preterminals. Multilamellar bodies, and increases in the number of dense core vesicles, dense bodies and secondary lysosomes were also observed after treatment with 6-OH-DA. The neurons showed clumping of mitochondria, which also appeared to be undergoing degenerative changes. The vacuoles in some supraependymal cells were greatly dilated as was the Golgi apparatus in the ependymal cells. The ependymal cell layer appeared to be intact, but there were areas immediately deep to this cell layer that contained large extracellular spaces. This increase in extracellular space was also commonly observed surrounding the perivascular spaces. These phenomena greatly contribute to the “spongy” appearance that the SFO takes on after 6-OH-DA administration.
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    URL: http://dx.doi.org/10.1007/BF00223222
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    The frontal ganglion of Periplaneta americana L. (insecta) (1978)
    Springer
    Cell & tissue research 191 (1978), S. 171-182 
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    ISSN: 1432-0878
    Keywords: Frontal ganglion ; Periplaneta ; Synaptic contacts ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The frontal ganglion, part of the stomatogastric nervous system, contains about 60 to 80 neurons, 25 to 30 μm in diameter. A well developed Golgi system, producing dense-core vesicles, lysosomes, multivesicular bodies and dense bodies are abundant. Glia elements are sparsely distributed. Many nerve fibres contain granules of different size and electron density. Five groups of fibres can be distinguished: Fibres with granules of about 200 nm (type A), fibres with granules of about 160 to 170 nm (type B), fibres with granules of about 80 to 100 nm (type C) and those with synaptic vesicles of 50 nm (type D) respectively. A fifth very small type contains neither vesicles nor granules. Special attention was paid to synaptic contacts. The divergent dyad seems to be the main type in the frontal ganglion. Frequently, neurosecretory endings are observed in presynaptic position. Immunocytochemical “staining” of neurosecretory material closely corresponds to the distribution of type A fibres, as observed electron microscopically. Immunoelectrophoresis of extracts from frontal ganglia with polyspecific anti-neurosecretion-serum reveals a single precipitation line, indicating that the immunocytochemical localization of neurosecretory material is due to reaction with a specific as well as a crossreagent antibody.
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    URL: http://dx.doi.org/10.1007/BF00223225
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    Effects of antimicrotubular agents on the fine structure of the Golgi complex in embryonic chick osteoblasts (1978)
    Springer
    Cell & tissue research 193 (1978), S. 247-257 
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    ISSN: 1432-0878
    Keywords: Osteoblasts (Chick embryo) ; Golgi complex ; Microtubules ; Colchicine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Embryonic chick frontal bones were cultured in the presence of colchicine or vinblastine and subsequently examined by transmission electron microscopy. In control cultures the osteoblasts showed a large Golgi complex consisting of dictyosomes arranged in a well-defined juxtanuclear area. Microtubules were particularly numerous within this Golgi area although they could be observed throughout the cytoplasm. Colchicine and vinblastine caused the disappearance of cytoplasmic microtubules, while bundles of 10nm diameter filaments appeared more frequently. In addition, cell polarity was lost and the Golgi complex became disorganized, with the dictyosomes randomly dispersed in the cytoplasm and showing a decreased number of cisternae and an increased number of vacuoles, the latter generally lacking stainable material. Increased number of autophagosomes were also noted. These findings indicate that microtubules function in the organization of the Golgi complex in osteoblasts. In view of the well documented role of this organelle system in collagen secretion it is suggested that previously observed secretory disturbances produced by antimicrotubular drugs may be due to a defective transfer of material to the dictyosomes and/or a defect in the packaging and transport of such material away from them.
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    URL: http://dx.doi.org/10.1007/BF00209038
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    Ultrastructural and cytochemical studies on the cytodifferentiation of duodenal endocrine cells (1978)
    Springer
    Cell & tissue research 194 (1978), S. 79-102 
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    ISSN: 1432-0878
    Keywords: Duodenum ; Endocrine cells ; Differentiation ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development and cytodifferentiation of endocrine cells that produce the gastrointestinal hormones gastrin, cholecystokinin and secretin have been studied by a combined fluorescence-cytochemical, immunocytochemical and ultrastructural approach. The results show that, during development, several ultrastructurally distinct cell types exhibit COOH-terminal gastrin and cholecystokinin immunoreactivity. Furthermore, some cells simultaneously contain both gastrin- and cholecystokinin-specific antigenic determinants. Studies on the time course of development of gastrin and cholecystokinin cells, together with the above-mentioned data, suggest that gastrin cells may be converted into cholecystokinin cells in development. During this period, gastrin, cholecystokinin and secretin cells store the biogenic monoamine, 5-hydroxytryptamine a feature not displayed by the adult counter-parts of these cells. In the adult duodenum, characteristic enterochromaffin (EC) cells store 5-hydroxytryptamin for which, evidence for a possible hormonal role has been presented. Taken together, our data indicate that the differentiation of duodenal endocrine cells occurs in distinct steps, each involving a restriction in the biosynthetic repertoire of the cell.
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    URL: http://dx.doi.org/10.1007/BF00209235
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    The ultrastructure of guinea pig heterophil granulocytes and the heterogeneity of the granules (1978)
    Springer
    Cell & tissue research 194 (1978), S. 183-205 
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    ISSN: 1432-0878
    Keywords: Bone marrow ; Heterophil granulocytes ; Granules ; Guineapig ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the heterophil granulocytes in the bone marrow of the guinea pig is described. During the maturation of these cells, three types of granule are formed, not only the azurophil and specific granules already described in other mammals but also a third type of granule referred to here as the nucleated granule. During the process of maturation of the cells, these three types of granule are formed successively. On this basis, two steps can be distinguished in the promyelocyte phase in which primary (nucleated and azurophil) granules are formed, i.e. an early and a late stage, nucleated granules being formed in early and azurophil granules in late promyelocytes. Secondary (specific) granules occur first in myelocytes. In mature heterophils of the guinea pig the granule population is composed of about 85% secondary granules, about 10% azurophil granules, and about 5% nucleated granules. The changes in the granule population during the maturation process were quantified. The observations and calculations point to the occurrence of three mitoses: one in the early and one in the late promyelocyte and the third in the myelocyte.
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    URL: http://dx.doi.org/10.1007/BF00220388
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    Cytochalasin B-induced changes in concanavalin A-activated lymphocytes (1978)
    Springer
    Cell & tissue research 194 (1978), S. 279-285 
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    ISSN: 1432-0878
    Keywords: 14C-thymidine incorporation ; Autoradiography ; Multinucleated blasts ; Electron microscopy ; Deformities of cellular membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cytochalasin B (CB) administered simultaneously with a mitogenic dose of concanavalin A (Con A) interferes with the activation process. This interference involves structural alterations of cellular membrane which do not include a reduced Con A-binding capacity. This conclusion is supported by the observation of deformities in both nuclear and cytoplasmic membranes in Con A-activated lymphocytes subsequently treated with CB. The high incidence of membrane blebs and pseudomyelin bodies in the cytoplasm points to a general effect of CB on the structural organization of membrane which may secondarily interfere with some specific event such as generation or transfer of signals for activation or cytokinesis.
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    URL: http://dx.doi.org/10.1007/BF00220394
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    Cold-induced insulin release in vitro: Evidence for exocytosis (1978)
    Springer
    Cell & tissue research 194 (1978), S. 387-398 
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    ISSN: 1432-0878
    Keywords: Isolated pancreatic islets ; Temperature ; Exocytosis ; Insulin ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exposure of isolated pancreatic islets (mouse or rat) to low temperature (2° C) evoked a threefold increase in insulin release irrespective of the glucose concentration in the incubation medium. Cold-induced release was transient and rewarming to 37° C restored the sensitivity of B-cells to glucose stimulation. In islets cooled to 2° C, exocytotic profiles could easily be detected both by thin-section and freeze-fracture electron microscopy. As revealed by the freeze-fracture technique, the number of exocytotic profiles per membrane area was increased three-to fourfold as compared to islet cells incubated at 20° C. This was paralleled by intracellular fusion of secretory vesicles. Cold-induced insulin release was not affected by theophylline, cytochalasin B, omission of extracellular Ca++ or D600. Replacement of extracellular Na+ with choline or sucrose suppressed the increase in insulin release and in frequency of exocytotic profiles recorded after exposure to 2° C. It is suggested that a redistribution of Ca++ from intracellular stores, possibly mediated by an increase in intracellular Na+, triggers exocytosis of insulin granules upon exposure to cold.
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    Presynaptic and postsynaptic organelles of synapses formed in cultures of previously dissociated mouse spinal cord (1978)
    Springer
    Cell & tissue research 194 (1978), S. 503-511 
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    ISSN: 1432-0878
    Keywords: Cell cultures ; Electron microscopy ; Synaptic organelles ; Spinal cord (mouse)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study describes some of the ultrastructural features of presynaptic and postsynaptic organelles at synapses developed in cultures of previously dissociated mouse spinal cord cells. Particular attention was paid to the agranular reticulum which is well developed at many presynaptic and postsynaptic sites, either in the form of simple tubules or cisternae, or more complex networks and often closely associated with mitochondria. In addition, the disposition of microtubules at and close to synaptic specializations is described. These and other features of synaptic zones, such as granular vesicles in presynaptic sites, are discussed in relation to cultures developed on feeder layers and synapses in vivo, and in relations to possible degenerative and regenerative events in the cell cultures.
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    URL: http://dx.doi.org/10.1007/BF00236169
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    Myosatellite cells associated with different muscle fibre types in the Atlantic hagfish (Myxine glutinosa, L.) (1978)
    Springer
    Cell & tissue research 195 (1978), S. 17-27 
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    ISSN: 1432-0878
    Keywords: Myosatellite cells ; Muscles ; Atlantic hagfish (Myxine glutinosa, L.) ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The incidence of myosatellite cells associated with “white” and “red” muscle fibres of the parietal muscle and “red” fibres of the craniovelar muscle was estimated by quantitative electron microscopy in the Atlantic hagfish (Myxine glutinosa, L.). Myosatellite cell nuclei constitute 3, 11 and 23 % of the total number of nuclei inside the basal lamina of the three types of muscle fibres, respectively. However, the total number of nuclei is highest in “white” fibres, most of the nuclei belonging to striated muscle cells. Myosatellite cell profiles in transverse sections constitute 23, 41 and 61 % of the number of muscle fibre profiles of the three types, respectively. The intervals between adjacent myosatellite cells are ∼ 135 μm in “white” fibres, ∼ 55 μm in “red” parietal fibres, and only ∼ 25 μm in craniovelar fibres. Since craniovelar fibres are also comparatively thin, myosatellite cells constitute a significant fraction of the volume inside the basal lamina in these fibres. The myosatellite cells are ∼ 30–50 μm long and up to 5 μm thick. Some myosatellite cells possess few organelles, whereas others appear to contain many free ribosomes, granular endoplasmic reticulum, prominent Golgi apparatus and lysosome-like bodies.
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    URL: http://dx.doi.org/10.1007/BF00233674
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    Ultrastructural localization of radiolabelled L-dopa in the endocrine hypothalamus of the rat (1978)
    Springer
    Cell & tissue research 195 (1978), S. 29-43 
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    ISSN: 1432-0878
    Keywords: Endocrine hypothalamus (rat) ; Arcuate nucleus ; L-dopa ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light and electron microscopic autoradiography has been employed to define the neuroanatomical patterns of uptake and binding of radiolabelled L-dopa in the endocrine hypothalamus of the rat. A dorsomedial continuum of arcuate and periventricular neurons selectively sequester 3H L-dopa 20 min following its intraventricular infusion. By 40 and 60 min following the infusion labelling of neurons is minimal and supports the notion of rapid degradation. Other cell compartments such as tanycytes demonstrate uptake of 3H L-dopa. The ultrastructural localization and distribution of radiolabelled L-dopa (or its metabolites) in the rodent hypothalamus is discussed with respect to mechanisms and cell compartments involved in neuroendocrine regulatory processes.
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    Ultrastructural evidence for adrenergic nerve degeneration in the guinea pig uterus during pregnancy (1978)
    Springer
    Cell & tissue research 195 (1978), S. 189-193 
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    ISSN: 1432-0878
    Keywords: Guinea pig uterus ; Myometrium, pregnancy ; Sympathetic nerves ; Electron microscopy ; Axon degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the guinea pig myometrium, the adrenergic nerves selectively demonstrated at the ultrastructural level after treatment with 5-OH-DA, show varying degree of degeneration during pregnancy. The changes are more extensive in a late gestational stage (40–45 days) than in an early one (20–25 days), and are particularly evident in the uterus overlying the conceptus as compared to the regions between the fetuses. Scattered degenerative changes were also observed in myometrial specimens from virgin animals, but probably reflect the normal continuous turnover of axons.
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    Non-ependymal cilia in the habenulae and the interpeduncular nucleus of the frog tadpole (1978)
    Springer
    Cell & tissue research 195 (1978), S. 527-533 
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    ISSN: 1432-0878
    Keywords: Ciliated neurons ; Habenula ; Interpeduncular nucleus ; Electron microscopy ; Rana esculenta, tadpole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cilia of the 9+2 pattern are found electron microscopically in nonependymal cells of the habenulae and the interpeduncular nucleus of the tadpole of Rana esculenta at an early stage of development (8 mm length, head to tip of tail). A comparison is made between these and the ependymal and sensory cilia in the same specimens. The cilia project into the neuropil emerging from a perikaryon rich in free ribosomes and displaying a prominent Golgi apparatus. These perikarya contain dense core vesicles. Synapses with vesicles of the clear spherical type have been observed along the ciliary shaft. On a purely morphologic basis the authors hypothesize that these cilia, at least in this early ontogenetic stage, may extend considerably the conducting surface of the cell and represent a sensory structure which could be stimulated by terminal processes belonging to distantly located cells. In addition, they could also be involved in the trophic exchange of material with the adjacent structures.
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    Phagocytosis of osteocytes by osteoclasts in femora of two week-old rabbits (1978)
    Springer
    Cell & tissue research 195 (1978), S. 557-564 
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    ISSN: 1432-0878
    Keywords: Osteoclasts ; Osteocytes ; Bone resorption ; Phagocytosis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The osteoclast-osteocyte relationship at the endosteal surface of femora of two-week old rabbits was studied. Light microscopic observations suggest that during physiological resorption phagocytosis by osteoclasts of osteocytes takes place. Serial sections confirm that the cells are totally engulfed within the cytoplasm of the osteoclasts. Ultrastructural studies support these findings and indicate that the initial stage of phagocytosis of the osteocytes consists of the insinuation of an extension of the ruffled border into the osteocyte lacuna. These extensions are seen to make close contact with the osteocytes prior to their engulfment by the osteoclasts and their final digestion within phagosomes.
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    URL: http://dx.doi.org/10.1007/BF00233897
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    The fine structural localization of acetylcholinesterase in the muscle spindle of the rat (1978)
    Springer
    Cell & tissue research 186 (1978), S. 39-52 
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    ISSN: 1432-0878
    Keywords: Muscle spindle ; Nerve endings ; Acetylcholinesterase ; Cytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Muscle spindles from lumbricalis muscles of the rat were incubated for acetylcholinesterase with a modified thiocholine-method of Lewis and Shute and examined by light and electron microscopy. All types of motor nerve ending showed heavy deposits of reaction product in the synaptic cleft. The underlying sarcoplasmic reticulum, transverse tubular system, and, when present, the envelope of sole plate nuclei were also stained. In the sensory region, the reaction was negative in the interface between the plasma membranes of the primary sensory terminal and muscle. One of two secondary sensory endings identified showed distinct reaction product in the cleft; the other secondary sensory ending showed no such reaction. Precipitates were present on the sarcolemma of the intrafusal muscle fibers in the polar and adjacent myotube regions, but not at the spindle equator. Extrafusal and intrafusal myelinated γ-nerve fibers and preterminal motor axons showed staining of the axolemma. Fibers with thick myelin sheaths and preterminal sensory axons were free of acetylcholinesterase activity, as were the unmyelinated nerve fibers.
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    The effect of the ionophore A23187 on amylase release, cellular integrity and ultrastructure of mouse pancreatic acini (1978)
    Springer
    Cell & tissue research 186 (1978), S. 287-295 
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    ISSN: 1432-0878
    Keywords: Pancreas ; Calcium ; Ionophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of the Ca2+ ionophore A 2317 on pancreatic amylase and lactate dehydrogenase (LDH) release, cellular electrolyte balance and ultra-structure were studied with the use of incubated pancreatic fragments. A 23187 (0.3 μM) in the presence of Ca2+, increased amylase release but at higher concentrations (1–10 μM) also increased LDH release and increased uptake of 14C-sucrose with concomitant loss of tissue K+ and gain in Na +. The ultrastructure of the majority of acini appeared normal and showed depletion of zymogen granules. Microtubules and microfilaments which have been implicated in the release process were normal or increased in number. In the absence of Ca+ the ionophore had no effect on secretion, cellular integrity or ultrastructure. It is concluded that A 23187 in the presence of Ca2+ increases amylase release by a mechanism comparable to the terminal steps in stimulussecretion coupling induced by physiological secretagogues. This provides further evidence that amylase release is mediated by a rise in cell Ca2+ although the mechanisms of the ionophore- and physiological secretagogue-induced rise in Ca+ are probably different. High concentrations of ionophore (〉 1 μM) also induce Ca2+ dependent damage in a fraction of the cells.
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    URL: http://dx.doi.org/10.1007/BF00225538
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    Ultrastructure of rat pituitary LH gonadotrophs in relation to serum and pituitary LH levels following repeated LH-RH stimulation (1978)
    Springer
    Cell & tissue research 190 (1978), S. 135-149 
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    ISSN: 1432-0878
    Keywords: Serum and pituitary LH ; Rat gonadotrophs ; LH-RH and Granule release, Synthesis and Degradation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of single and repeated LH-RH injections at 120 min intervals on female rat LH gonadotrophs and on pituitary and serum LH levels were investigated using electronmicroscopy and radioimmunoassay. A temporary stimulation of granule release, of protein and new granule synthesis and of the accumulation of lysosomal structures was found in LH cells after the first LH-RH injection. The temporary stimulations were massively enhanced after the second injection. These consecutive yet in their time-sequence overlapping processes account for the initial depletion of secretory granule content (3–15 min after LH-RH injection), for the subsequent regranulation and accumulation of granules above control levels (60–120 min after injection) and also for the reduction in the number of granules to control levels (150 min after LH-RH injection and thereafter). Increased polymorphic lysosomal structures are believed to be responsible for this reduction of excess granules. The amount of assayable pituitary and serum LH generally corresponds with the morphological changes observed in LH-gonadotrophs, thus further substantiating the above observations. A schema which summarizes the observed morphological and hormonal changes in their time-sequence in response to LH-RH stimulation depicts the short-term regulation of secretory processes in female gonadotrophs.
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    URL: http://dx.doi.org/10.1007/BF00210043
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    Changes in the surface morphology of the rabbit endometrium related to the estrous and progestational stages of the reproductive cycle (1978)
    Springer
    Cell & tissue research 190 (1978), S. 207-222 
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    ISSN: 1432-0878
    Keywords: Endometrium ; Rabbit ; Reproductive cycle ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes occurring on the surface of the uterine luminal epithelium of the rabbit during the estrous and progestational stages of the reproductive cycle were examined by scanning and transmission electron microscopy. The findings demonstrate that the uterine epithelium, or endometrium, contains two cell types: ciliated cells and nonciliated, microvillous cells. In estrous animals, ciliated cells, although not very numerous, were usually observed in small groups. However, at increasing intervals of time following mating, ciliated cells progressively disappeared from the endometrium until approximately eight to ten days post coitum, when they became scare. From several hours to four to five days following mating, extensive changes occurred on the surfaces of microvillous cells. When observed by TEM, these elements contained organelles typical of cells involved in the synthesis and secretion of glycoproteins. Furthermore, microvillous cells during this period displayed numerous apical protrusions of different sizes and shapes and containing material of varying electron density. Parallel SEM examinations of the same material confirmed the presence of these protrusions. Some of the protrusions appeared as spheroidal masses attached to the cytoplasm by means of a cytoplasmic strand. Other surface masses were clearly unattached to the cell surface and were distributed (1) on the surface of microvillous cells, (2) on the cilia of adjacent ciliated cells, and (3) on the surface of spermatozoa. Changes occurring on the luminal surface during the early postcoital period are interpreted as an expression of morphodynamic processes likely involving coupled secretion (exocytosis) and resorption (endocytosis) of luminal material. The observations presented here also demonstrate that between six and ten days post coitum, the rabbit endometrium contained increasing numbers of enlarged, nonciliated cells that probably arose by the fusion of smaller, microvillous elements.
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    Fine structure and composition of the submucous nerve plexus of the guinea-pig trachea (1978)
    Springer
    Cell & tissue research 190 (1978), S. 301-316 
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    ISSN: 1432-0878
    Keywords: Trachea (Guinea-Pig) ; Plexus submucosus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the nerves forming the submucous plexus of cervical and thoracic parts of the trachea was studied in the guinea-pig. Specimens were obtained from 6 animals perfused with warm fixative and from 6 animals in which pieces of trachea were incubated in buffer containing 5-hydroxydopamine before being immersed in cold fixative. Of the two types of axonal terminal identified in the nerves, one contained mainly large dense-cored vesicles, and the second contained numerous small vesicles. In specimens incubated in 5-hydroxydopamine, the small vesicles of the latter terminals exhibited the electron-dense cores which are characteristic of adrenergic axonal terminals. Counts made on perfused specimens showed that, in both the thoracic and cervical parts of the trachea, the density of adrenergic terminals was higher than that of terminals containing mainly large dense-cored vesicles. Overall terminal density was, however, higher in the thoracic than in the cervical part of the trachea, and estimates of nerve size showed that this was associated with the presence in the thoracic plexus of a substantially greater proportion of nerves with less than 6 axons. The possible function of the nerves in the control of the calibre of the submucous blood vessels was discussed.
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    Gonadotropic cells in the Atlantic salmon, Salmo salar (1978)
    Springer
    Cell & tissue research 191 (1978), S. 187-203 
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    ISSN: 1432-0878
    Keywords: Pituitary ; GTH-cells ; Teleost ; Immunofluorescence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The gonadotropin-producing cells (GTH-cells) in the Atlantic salmon were studied light and electron microscopically before, during and after spawning, and after injections of luteinizing hormone-releasing hormone (LH-RH). The double immunofluorescent technique was applied using rabbit anti-carp GTH as the first antibody. Numerous immunofluorescent cells were observed throughout the pars distalis, but very few in the pars intermedia. These cells are basophilic and PAS-positive, and ultrastructurally classified as globular gonadotropes. Only one gonadotropic cell type could be identified; its size, morphology and fine structure vary considerably. In the same specimen the GTH-cells can be predominantly globular or vesicular in appearance, depending on the reproductive phase of the fish. At spawning and after LH-RH injection, many GTH-cells reach a vacuolar stage; the content of the vacuoles is not immunofluorescent. Another cell type, which resembles GTH-cells in semithin sections, did not show gonadotropic properties; its nature and functional significance are unknown. In addition, the present study revealed an increase in the synthetic and exocytotic activity of prolactin cells after LH-RH injections. It is suggested that LH-RH mediates this effect via LH and eventually via estradiol.
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    URL: http://dx.doi.org/10.1007/BF00222419
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    Crystalloid structures within giant mitochondria of the prothoracic glands of Spodoptera littoralis (Bois) (Lepidoptera) (1978)
    Springer
    Cell & tissue research 191 (1978), S. 357-362 
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    ISSN: 1432-0878
    Keywords: Prothoracic glands ; Insects ; Electron microscopy ; Macromitochondria ; Crystalloid organization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the prothoracic glands of Spodoptera littoralis was investigated during the first half of the last larval instar. The secretory cells have two types of mitochondria, micromitochondria and macromitochondria. The micromitochondria have rounded to elongated profiles and sometimes branch. They contain lamellar, tubular and also tubulo-vesicular cristae. The macromitochondria appear generally rounded or oval and possess tubular cristae. Many regular parallel membranes appear within macromitochondria. Favorable sections show tubular structures packed in honeycomb fashion. The mitochondrial cristae are in connection with the tubular structures. Honeycomb and parallel membranes increase in number as the size of the macromitochondria increases.
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    URL: http://dx.doi.org/10.1007/BF00222430
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    Ultrastructure of venules in the cat brain (1978)
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    Cell & tissue research 192 (1978), S. 461-474 
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    ISSN: 1432-0878
    Keywords: Cerebral vessels ; Venules ; Pericytes ; Electron microscopy ; Microvasculature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intracerebral venules of the cat were examined to establish criteria for a distinct separation between the venous and arterial system, and to characterize, in greater detail, the mural construction of individual venules. The intracerebral venules were compared with those of other organs. Venules do not have a vascular wall composed clearly of endothelium, media, and adventitia, as is characteristic of arteries and arterioles. The venous endothelium has a similar structure to that of capillaries. The periendothelial cells of the venule differ in shape depending on the vascular diameter. The number of periendothelial cell processes in postcapillary venules increases progressively. Segments in which the basal lamina of the endothelium merges with that of the glia cover a smaller portion of the circumference than in venous capillary loops. In collecting venules, the endothelium is almost completely enveloped by periendothelial cells which have a larger number of filaments. There are no typical smooth muscle cells in the intracerebral venules. The perivascular space becomes wider in collecting venules, contains adventitial cells, phagocytes and a great number of collagen fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212326
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    Ultrastructure of the different zones of the tectorial membrane (1978)
    Springer
    Cell & tissue research 193 (1978), S. 11-23 
    Details
    ISSN: 1432-0878
    Keywords: Tectorial membrane ; Organ of Corti ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tectorial membrane (t.m.) of mammals, which lies over the organ of Corti, is made up of an agglomerate of protofibrils of varying degrees of hydration. Two types of protofibrils are clearly distinguishable in the mouse t.m. While type-A protofibrils are straight and unbranched (thickness: 110Å) demonstrating a periodic structure (period = 70Å), type-B protofibrils are branched and coiled (thickness: 150–200Å). These protofibrils could be systematically ordered according to the different t.m. zones. Type-A protofibrils predominate in the basal layer and in the entire middle zone, where they are interlaced with strongly hydrated type-B protofibrils. Weakly hydrated type-B protofibrils essentially make up the marginal zone (with the marginal net), the covering net, Hensen's stripe and the immediate contact layer with the limbus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221597
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    Mixed (chemical and electrical) synapses on frog spinal motoneurons (1978)
    Springer
    Cell & tissue research 193 (1978), S. 41-59 
    Details
    ISSN: 1432-0878
    Keywords: Electrical synapse (frog) ; Electrotonic coupling ; Electron microscopy ; Freeze fracture ; Gap junction ; Mixed synapse ; Motoneuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Freeze-fracture replicas and ultrathin sections were used to characterize the gap junctions on the somata and large dendrites of frog motoneurons found earlier by Sonnhof et al. (1977). In freeze-fracture replicas one of the specific features of these relatively frequent gap junctions is the presence of circular regions of non-junctional membrane (“fenestrae”) within areas of typical gap junction appearance displaying P-face particles or E-face pits. Such “fenestrated” gap junctions are mostly associated with membrane specializations indicative of the active zone of a chemical synapse (including vesicle attachment sites in non anaesthetized animals) to constitute mixed synapses. These findings could be verified in ultrathin sections, which revealed that the vesicles of the chemical component of the mixed synapses were spherical and agranular. Our results suggest that the mixed synapses are predominantly axo-somatic and axo-dendritic. The existence of dendro-dendritic gap junctions in the ventral horn region as described by Sotelo and Taxi (1970) was verified in ultrathin sections; they were rare, solely electrotonic in character, and probably represent the morphological basis for the VR-EPSP (Katz and Miledi, 1963; Kubota and Brookhart, 1963), i.e. electrotonic coupling between motoneurons of different spinal segments (Washizu, 1960). Electrotonic coupling can also be demonstrated between motoneurons and afferent fibers of the dorsal root and the lateral column. Electrotonic potentials recorded within motoneurons during electrical stimulation of dorsal root or lateral column precede the chemical postsynaptic potentials; after Mn2+ blockade of chemical synaptic transmission, the electrotonic component persists. Some fibers of these afferent pathways are therefore assumed to act monosynaptically on the motoneuron via mixed axo-somatic and axo-dendritic synapses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221600
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    Apical protuberances of supporting cells in the regio olfactoria of the mole, Talpa europaea, Linnaeus, 1758 (Insectivora, Talpidae) (1978)
    Springer
    Cell & tissue research 193 (1978), S. 175-178 
    Details
    ISSN: 1432-0878
    Keywords: Olfactory epithelium ; Supporting cells ; Protuberances ; Electron microscopy ; Insectivora ; Talpidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The regio olfactoria of the mole, Talpa europaea, was studied by scanning and transmission electron microscopy. Peculiar structural differentiations, i.e. ovoid-shaped, balloon-like protuberances were found on the surface of the supporting cells. The apical portion of these protuberances contained finely dispersed granular material, whereas in their central part vesicular extensions of the smooth endoplasmic reticulum were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221610
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  • 86
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    Recent observations on the ultrastructure of human urothelium (1978)
    Springer
    Cell & tissue research 193 (1978), S. 543-560 
    Details
    ISSN: 1432-0878
    Keywords: Human ; Urinary bladder epithelium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscopic study of normal bladder urothelium of elderly patients ranging in age from 61 to 82 years has shown the occurrence of unusually thin regions consisting of either one or two layers of undifferentiated cells interspersed between 3–4 cell layers thick regions. A morphometric study has confirmed the existence of a pattern of cytodifferentiation in cells of the thick region. The generally microvillous nature of the luminal surface is attributed to incompletely differentiated cells that have come to occupy the superficial layer. The lack of thickened and/or asymmetric membrane plaques in luminal plasma as well as the dearth of characteristic precursor vesicles in the cytoplasm are also explicable in terms of a failure of normal cell differentiation. It is suggested that the unusual features noted are consequences of tissue ageing rather than prognostic of cancer. There are indications that the aged urothelium may be prone to increased leakiness and the bladder tissues may therefore be at greater risk from urine-borne chemicals and carcinogens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225350
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    The effects of vinblastine on acinar cells of the exorbital lacrimal gland of the rat (1978)
    Springer
    Cell & tissue research 195 (1978), S. 227-237 
    Details
    ISSN: 1432-0878
    Keywords: Vinblastine ; Lacrimal gland ; Electron microscopy ; Autophagy ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of vinblastine treatment on acinar cells of the rat exorbital lacrimal gland were studied by electron microscopy. Experimental animals of both sexes were given single intraperitoneal injections of (1) vinblastine (4mg/kg body weight) at 1 to 24 h before sacrifice; (2) pilocarpine (20 mg/kg b.w.) for 1 h; or (3) vinblastine for l h followed by pilocarpine for 1 h. Vinblastine treatment caused a number of changes including autophagocytosis, formation of intracisternal granules, and alteration of secretory granules. These changes varied in extent and onset between male and female rats. In addition, the Golgi apparatus was reduced in size and dispersed throughout the cytoplasm. Mitotic figures were commonly observed. Moreover, vinblastine inhibited the pilocarpine-stimulated degranulation of the acinar cells. In view of the known anti-microtubular action of vinblastine, these results suggest that microtubules are involved in various aspects of the transport, packaging, and secretion of exportable proteins in the lacrimal gland. Additionally, autophagocytosis and alteration of secretory granules may partially result from the interaction of vinblastine with membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236721
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  • 88
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    Calcium and sulphur in neurosecretory granules and calcium in mitochondria as determined by electron microscope X-ray microanalysis (1978)
    Springer
    Cell & tissue research 186 (1978), S. 453-463 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretory granules (Insects) ; Mitochondria ; Calcium ; Sulphur ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sections of neurosecretory cells fixed in glutaraldehyde and osmium tetroxide were studied by means of an EMMA-4 analytical microscope. Secretory granules in neurosecretory cells of the corpus cardiacum and of the brain, both in the desert locust Schistocerca and in the blowfly Calliphora, as well as neurosecretory granules in posterior pituitaries of the frog Rana and of the albino rat all contain a high concentration of calcium. A distinct sulphur peak was also a constant feature. In neurosecretory cells of the corpus cardiacum of Schistocerca the chromatin contained a high concentration of calcium. The mitochondria also contained much calcium, but part of this disappeared during preparation except when fixative and wash contained calcium chloride. By block staining with uranyl acetate most calcium is displaced from the mitochondria, whereas most of the calcium remains in the neurosecretory granules. Since the calcium peaks in spectra from neurosecretory granules appear of similar size, regardless of variations in the preparative procedure, this calcium must be firmly bound. The possible role of the calcium bound to the neurosecretory substance is discussed. The presence of sulphur in insect neurosecretory granules indicates the presence of a protein besides the hormone, i.e., an insect neurophysin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224934
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    Ultrastructure of the age-involuted adult human thymus (1978)
    Springer
    Cell & tissue research 186 (1978), S. 507-525 
    Details
    ISSN: 1432-0878
    Keywords: Human thymus ; Age involution ; Cellular composition of cortex, medulla and connective tissue ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Age involuted thymus tissue from a middle aged (33 years) and an old (63 years) man have been examined by electron microscopy and compared with thymus tissue from children. Biopsies had been taken during surgical correction of congenital heart defects. The fine structural architecture of cortex, medulla and connective tissue in the remaining lymphatic islands in the adult thymus investigated was not different to the thymus of children. We were surprised to find vigorous lymphocytopoiesis in the cortical regions and to recognize extended areas of medulla with a cellular composition which obviously provides the same microenvironment for T-cell maturation as the medulla of the non involuted thymus. Our findings are discussed in relation to the increasing arguments that the human thymus serves an immunological function throughout life.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224939
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    Cellular organization of the embryonic lobster heart (1978)
    Springer
    Cell & tissue research 188 (1978), S. 171-187 
    Details
    ISSN: 1432-0878
    Keywords: Embryonic heart ; Crustacea (Homarus americanus) ; Cardiac muscle ; Intercellular junctions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cellular organization of the embryonic heart of the lobster Homarus americanus was examined in 6-week and 6-month-old animals. The heart wall consists of an outer adventitial layer of fibroblast cells and an inner layer of transversely striated myocardial cells. Present in close association with the myocardium are cardiac neurons, hemocytes and so-called storage cells. Adjacent fibroblasts form fasciae adhaerentes and gap junctions. Adherent junctions also occur between fibroblasts and myocardial cells. Intercalated discs and differentiated membrane regions of close apposition (4 nm) occur between adjacent myocardial cells. The cardiac neurons form a ganglion that contains four small and five large somata. Regions of neuropil are present. Motor axons arising from the cardiac ganglion form neuromuscular synapses with the myocardial cells. The storage cells contain large inclusions and form gap junctions with the myocardial cells. They may supply nutritive material to the developing myocardium. The heart at 6 weeks is about 200 μm long and 160 μm wide. At 6 months, it is about 300 μm long and 250 μm wide. The myocardium at 6 weeks is one cell layer thick, and the cells are from 2–6 μm in maximum width. At 6 months the myocardium is 2–4 cells thick, and the cells are from 6–12 μm in width. Therefore, the myocardium grows by an increase in the number and size of the myocardial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222629
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