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  • 1
    Electronic Resource
    Electronic Resource
    Effects of oxygen concentration on embryonic development in rats: a light and electron microscopic study using whole-embryo culture techniques (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 337-343 
    Details
    ISSN: 1432-0568
    Keywords: Hyperoxia ; Hypoxia ; Teratogenesis ; Rat embryo ; Whole-embryo culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By using a whole-embryo culture technique (New 1978), the effects of oxygen concentration (5%, 20% and 95% oxygen) on embryonic development in the rat were investigated by light and electron microscopy. The best embryonic development occurred when the 9.5-day-old embryos were cultured for 24 h with 5% oxygen, and the 10.5-day-old embryos with 20% oxygen (optimum oxygen concentration). When the 9.5- and 10.5-day-old embryos were cultured for 24 h with too little or too much oxygen, retardation of the embryonic growth and abnormal development was observed. Using light microscopy, numerous degenerating cells, exhibiting granular deposits in the cytoplasm, were seen, but the distribution of the degenerating cells was quite different between the two groups. With electron microscopy, the most striking feature of the degenerating cells in the embryos cultured with too little oxygen, was the extreme swelling of the mitochondria without any morphological alterations of the nucleus or the other cell organelles. On the other hand, the characteristic feature of the degenerating cells in the embryos exposed to too much oxygen, was the formation of phagolysosomes in the cytoplasm. Morphological alterations of the nucleus or mitochondria were not evident. In the present study, the possible teratogenic mechanism of too much or too little oxygen in the whole-embryo culture of the rat embryo is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698664
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  • 2
    Electronic Resource
    Electronic Resource
    pH-Dependent conversion of liver-membranous alkaline phosphatase to a serum-soluble form by n-butanol extraction
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 126 (1985), S. 89-95 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0006-291X(85)90575-3
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  • 3
    Electronic Resource
    Electronic Resource
    Optical waveguide lens measurement using an image processing system (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 776-777 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An image processing system was used to evaluate optical waveguide lens performance. The focal length, the focal spot size, and the efficiency of geodesic lenses formed on ion-exchanged waveguides were measured nondestructively, and beams propagating along the curved guiding surface of the waveguide lens were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99280
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  • 4
    Electronic Resource
    Electronic Resource
    Three-dimensional simulation of dye laser amplifiers (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 1109-1115 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A time-dependent and three-dimensional dye laser amplifier simulation is presented. Its amplified spontaneous emission (ASE) is simulated by distinguishing the propagating directions of the angularly divided ASE, which makes it possible to simulate both the laser and ASE. Strong generation of the ASE is seen from the part of the excited volume where there is no input signal, indicating that ASE greatly depends on the input-beam geometrical profile, as well as its temporal matching with the pumping beam.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351274
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  • 5
    Electronic Resource
    Electronic Resource
    Comparative enzyme histochemical study on the visceral yolk sac endoderm in the rat in vivo and in vitro (1984)
    Springer
    Histochemistry and cell biology 81 (1984), S. 409-415 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical study of the visceral yolk-sac endoderm of the rat was performed in vitro (whole-embryo culture for 24, 48 and 72 h explanted at 9.5 days of gestation) and in vivo (10.5, 11.5 and 12.5 days of gestation) in order to compare the distribution and activity of various enzymes involved in the digestion and energy metabolism in both systems. It was shown that, both in vitro and in vivo γ-glytamyltransferase and dipeptidylpeptidase IV are demonstrable in the apical cell membranes (membranebound hydrolases), while acid phosphatase, dipeptidylpeptidases I, II and acid β-galactosidase are concentrated in the supranuclear vacuoles (lysosomal hydrolases), and cytoplasmic lactate dehydrogenase and mitochondrial enzymes (succinate dehydrogenase, NAD-dependent isocitrate dehydrogenase, cytochrom oxidase) are localized in the whole cytoplasm and mainly in the apical cytoplasm, respectively, of the visceral yolk-sac epithelium. In vivo, the activity of all enzymes increased until 12.5 days, but in vitro, this activity increased only until 48 h after the start of culture (corresponding to 11.5 days in vivo). Comparison of the yolk sacs at 10.5 and 11.5 days in vivo with those after 24 and 48 h in vitro showed that the activities of all the investigated enzymes were almost identical. Yolk sacs which were cultured for 72 h showed lower activities of lysosomal and mitochondrial enzymes than those at 12.5 days in vivo. It is concluded that the digestive function and energy metabolism of the visceral yolk-sac epithelium are almost identical in vitro and in vivo at 10.5 and 11.5 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00514337
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  • 6
    Electronic Resource
    Electronic Resource
    Study on membrane recycling in the rat visceral yolk-sac endoderm using concanavalin-A conjugates (1985)
    Springer
    Histochemistry and cell biology 83 (1985), S. 359-367 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The internalization and intracellular movements of apical-cell-membrane material were investigated in the endodermal cells of cultured visceral yolk-sacs of rats (whole-embryo culture; explanted at 10.5 days of gestation and cultured for 24h) using horseradish peroxidase- and ferritin-labelled concanavalin A (Con-A HRP, Con-A Fer). When visceral yolk-sac endoderm was exposed to Con-A HRP or Con-A Fer for 5 min at 4°C, the apical cell membranes containing a well-developed fuzzy coat were heavily labelled, whereas apical vacuoles, lysosomes and apical canaliculi were not. Incubation of Con-A-labelled endoderm for 5 60 min at 20° and 37°C in Con-A-free serum resulted in a temperature-dependent internalization of membranebound lectin into coated vesicles, apical vacuoles and lysosomes, and the apical cell membranes were cleared of the heavy labelling. With increasing incubation time, the number of labelled vacuolar structures and the intensity of their labelling decreased gradually, whereas the number of labelled apical canaliculi increased. Thus, after 30 and 60 min at 37°C, most of the apical canaliculi contained high concentrations of the markers. It was possible to observe labelled apical canaliculi that were in continuity with labelled apical vacuoles and lysosomes as well as with the apical cell membrane. These findings in rat endodermal cells indicate that constitutents of the apical cell membrane are internalized in apical vacuoles and lysosomes, and are then brought back to the apical cell membrane by the apical canaliculi, which concentrate and store this membrane material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00684383
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  • 7
    Electronic Resource
    Electronic Resource
    Proliferating ability, morphological development and acetylcholinesterase activity of the neural tube cells in early chick embryos (1982)
    Springer
    Histochemistry and cell biology 76 (1982), S. 303-314 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using 3H-thymidine autoradiography and AChE histochemistry at the electron microscopic level on the same sections, the interrelationships between loss of proliferating ability, morphological development and increase of AChE activity during the course of differentiation of the neural tube cells were investigated in early chick embryos. The neural tube wall consisted of spindle-shaped cells with no AChE activity, weakly positive spindle-shaped cells showing AChE activity in the cisternae of the nuclear envelope and in a few short profiles of r-ER, moderately positive spindle-shaped cells showing AChE activity in the nuclear envelope and in a moderate number of r-ER profiles and intensely positive large round cells showing AChE activity in the nuclear envelope and in a large number of r-ER profiles. Nuclei of the AChE-negative, weakly positive and moderately positive cells were located in the ependymal layer (matrix). The AChE-intensely positive cells were in the mantle layer. The AChE-negative and weakly positive cells were capable of proliferation and were regarded as undifferentiated neuroepithelial cells. In contrast, the moderately positive and intensely positive cells were no longer capable of proliferation and were considered to be neurons. These findings indicate that the r-ER increases rapidly in amount and volume in newly formed neurons soon after their final cell division, and that AChE increases in the neurons in parallel to the development of the r-ER.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00543953
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  • 8
    Electronic Resource
    Electronic Resource
    Acetylcholinesterase activity in neural crest cells of the early chick embryo (1983)
    Springer
    Histochemistry and cell biology 78 (1983), S. 81-93 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance and distribution of AChE activity in the neural crest cells of the chick embryo were histochemically investigated. Prior to closure of the neural tube, neural crests were not demonstrated and most of the cells constituting the neural plate and the more lateral ectoderm were AChE-negative. With the closure of the neural tube, the neural crests assumed the form of a cell mass in its mid-dorsal portion and AChE activity was demonstrated in some elements of both tube and crests. The neural crest cells beginning to migrate ventrally or laterally were AChE-positive, and some showed intense enzymatic activity. Electron microscopically, the neural crest cells and the cells migrating from the neural crest displayed AChE activity in the cisternae of the nuclear envelope and in a few r-ER profiles, but were morphologically undifferentiated. As assessed by 3H-thymidine autoradiography, these cells possessed the potential to proliferate. These findings indicate that with the formation of the neural tube and neural crest, cells constituting these structures begin to differentiate with respect to AChE activity and that the enzyme appears in the neural crest cells before the onset of neuronal differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00491114
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  • 9
    Electronic Resource
    Electronic Resource
    Histochemical studies of enzymes of the energy metabolism in postimplantation rat embryos (1988)
    Springer
    Histochemistry and cell biology 88 (1988), S. 489-495 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using histochemical procedures for the detection of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and cytochrome c oxidase (cytox), we investigated the levels of these enzymes of the energy metabolism in postimplantation rat embryos (9.5–12.5 days of gestation). On day 10.5 of gestation, the neural tube, somites, myocardium, and mesenchyme displayed moderate levels of LDH activity; this activity gradually increased in strength, so that, on day 12.5 of gestation, intense LDH activity was uniformly distributed in these intraembryonic tissues. In contrast to LDH, distinet regional differences in the distribution of SDH and cytox were detected. On day 10.5 of gestation, the myocardium exhibited weak to moderate SDH and cytox activity, and on day 11.5, the myocardial activity of these enzymes had become moderate to intense. However, in all other embryonic tissues, e.g., the neural tube and somites, only weak SDH and cytox activity was present. On day 12.5 of gestation, the myocardium displayed very intense SDH and cytox activity, whereas the mantle layer of the neural tube, the spinal ganglia, and the myotomes exhibited only moderate levels of SDH and cytox activity. In the matrix of the neural tube and mesenchyme, these enzyme activities remained at low levels. At electron microscopy, cytox activity was detectable in the spaces between the inner and outer membranes as well as in the intracristal spaces of mitochondria. In general, cytox activity increased in paralled with the differentiation of mitochondria (i.e., increased mitochondrial numbers and size, and the development of mitochondrial cristae), but when the distribution of the cytox activity was considered in detail, it was found to differ among mitochondria. The relationship between, on the one hand, changes in the enzymatic patterns with a bearing on the energy-yielding metabolism and, on the other hand, cellular differentiation during major organogenesis in rat embryos is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570314
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of leupeptin on endocytosis and membrane recycling in rat visceral yolk-sac endoderm (1986)
    Springer
    Histochemistry and cell biology 85 (1986), S. 169-175 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of exposure to leupeptin (25 μg/ml for 24 h) on the endocytotic activity and the membrane flow of apical cell membranes was studied in endodermal cells of cultured rat visceral yolk sacs by applying a doublelabelling method using concanavalin-A ferritin (Con-A Fer) and horseradish peroxidase (HRP). Control and leupeptintreated yolk sacs were labelled with Con-A Fer at 4°C and then incubated with HRP for 5, 15 or 60 min at 37°C. In controls, HRP reaction product was detected after 5 min in many of the apical vacuoles as well as a few lysosomes; after 15 min, reaction product was observed in all apical vacuoles and in lysosomes of various sizes. These HRP-positive structures usually contained a variable amount of membrane-bound Fer. After 60 min, all apical vacuoles and almost all lysosomes exhibited HRP reactions, but only some of these structures contained Fer particles. At this time, many apical canaliculi (which are involved in membrane recycling) exhibited positive HRP reactions and sometimes also contained Fer particles. In leupeptin-treated cells, HRP reaction product and variable amounts of membrane-bound Fer particles were found in apical vacuoles after 5 min; after 15 min, both labels were also observed in some small lysosomes, and after 60 min, they were found in all apical vacuoles as well as some small and middle-sized lysosomes. Significantly fewer labelled apical vacuoles, lysosomes and apical canaliculi were present after leupeptin treatment than in controls at corresponding times. At all times examined, the giant lysosomes found in leupeptintreated cells did not exhibit any labelling. These findings indicate that, after leupeptin treatment, both endocytotic activity and membrane recycling decrease, and that fusions of the apical vacuolar system with giant lysosomes are retarded or inhibited.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00491765
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