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  • Electron microscopy
  • Springer  (75)
  • 1995-1999  (75)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    The effect of the illumination time when treating port-wine stains (1995)
    Springer
    Lasers in medical science 10 (1995), S. 93-104 
    Details
    ISSN: 1435-604X
    Keywords: Copper vapour laser ; Electron microscopy ; Illumination time ; Numerical modelling ; Optimal treatment ; Port-wine stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50μm diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02150846
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  • 2
    Electronic Resource
    Electronic Resource
    Renewing olfactory receptor neurons in goldfish do not require contact with the olfactory bulb to develop normal chemical responsiveness (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 425-437 
    Details
    ISSN: 1432-1351
    Keywords: Key words Olfactory receptor cells ; Olfactory bulbectomy ; Olfactory axotomy ; Electrophysiology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study investigated whether contact with the olfactory bulb was necessary for developing and renewing olfactory receptor neurons (ORNs) to attain normal odorant responsiveness, and whether the anatomical and functional recoveries of the olfactory epithelium were similar in both bulbectomized (BE) and bilaterally axotomized (AX) preparations. In vivo electrophysiological recordings were obtained in response to amino acids, a bile acid [taurolithocholic acid sulfate(TLCS)] and a pheromonal odorant [17α, 20β,-dihydroxy-4-pregnen-3-one (17,20P)] from sexually immature goldfish. Both transmission and scanning electron microscopy indicated that the olfactory epithelium degenerated in BE and AX goldfish. Within 1–2 weeks subsequent to the respective surgeries, responses to high concentrations (〉0.1 mmol · l−1) of the more stimulatory amino acids remained, whereas responses were no longer obtainable to TLCS and 17,20P. At 4 weeks, responses to amino acid stimuli recovered to control levels, while responses to TLCS and 17,20P were minimal. By 7 weeks post bilateral axotomy, the olfactory epithelium recovered to a condition similar to control sensory epithelium; however, the rate of degeneration and proliferation of receptor neurons in BE preparations appeared to remain in balance, thus blocking further recovery of the olfactory epithelium. At 7 weeks post surgery, odorant responses of AX and BE goldfish to TLCS and 17,20P were still recovering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050126
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  • 3
    Electronic Resource
    Electronic Resource
    Some examples of electron microscopy studies of microstructures and phase transitions in solids (1995)
    Springer
    Meccanica 30 (1995), S. 433-438 
    Details
    ISSN: 1572-9648
    Keywords: Electron microscopy ; Microstructures ; Phase transitions ; Solid mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario Si presentano i risultati di alcuni studi fatti attraverso la microscopia elettronica sulle microstrutture relative a transizioni di fase in una varietà di materiali. I casi comprendono leghe binarie e ternarie, superconduttori TC e materiali C60 e C70; le transizioni esaminate sono diffusionali, displacive o di entrambi i tipi.
    Notes: Abstract In this contribution the results of some electron microscopy studies on microstructures related with phase transitions in a variety of materials will be presented. The materials include binary and ternary alloys, high TC superconductors as well as C60 and C70 fullerenes, while the transitions can be diffusional, displacive or both.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01557075
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  • 4
    Electronic Resource
    Electronic Resource
    Scots pine needle injuries at subarctic industrial sites (1997)
    Springer
    Trees 11 (1997), S. 378-387 
    Details
    ISSN: 0931-1890
    Keywords: Key words Pinus sylvestris (L.) ; Electron microscopy ; Heavy metals ; Multi-stress-symptoms ; SO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Injuries to needles of Scots pines (Pinus sylvestris L.) growing in nutrient-poor soils on the Kola Peninsula collected in April 1991 were studied on a gradient of increasing distances (10 – 115 km) from the Monchegorsk nickel smelter, Russia, which emits SO2, Ni and Cu. The condition of the mesophyll cells was quantified from needles of the two latest age classes using a light and an electron microscope. The damage to the ultrastructure consisted of multistress symptoms caused by excess sulphur, heavy metals, frost, acidic precipitation and ozone. Injuries were most commonly manifested in the form of dark, irregularly shaped chloroplasts with protrusions and light thylakoids and plastoglobuli. These symptoms gradually disappeared with increasing distance and decreasing deposition rate. Concentrations of sulphur, copper and nickel decreased towards more distant sites where normal levels of the latter two elements were reached. Sulphur concentrations remained above background throughout the distance gradient. In the closest plots to the smelter area, cell collapse under the stomata and epidermis related to acute SO2 and heavy metal effects was found, whereas further away symptoms were more diverse, pointing towards the effects of ozone, acidic deposition and thereby decreased frost tolerance. The additive multistress symptoms were clearly seen in the area up to 40 km from the smelter where needle Cu concentration was above 110 ppm, Ni concentration above 39 ppm and S concentration above 1343 ppm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004680050099
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of brefeldin-A and monensin on organelle distribution and morphology in the preimplantation mouse embryo (1997)
    Springer
    Development genes and evolution 206 (1997), S. 503-514 
    Details
    ISSN: 1432-041X
    Keywords: Key words Preimplantation mouse embryo ; Brefeldin-A ; Monensin ; Golgi ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The intracellular trafficking of integral membrane and secreted proteins is likely to be a key element involved in the morphogenesis and differentiation of the early mammalian embryo. In this study, we used transmission electron microscopy (TEM) to analyse the effects of brefeldin-A (BFA) and monensin, well known inhibitors of vesicular protein trafficking in somatic cells, on the structure of preimplantation mouse embryos. Both BFA and monensin distinctively altered the morphology of Golgi compartments in the blastomeres of treated morulae. BFA-treated morulae lacked recognizable Golgi complexes but possessed heterogeneous organelle clusters consisting of an abundance of smooth tubular and vesicular membrane compartments in addition to mitochondria, endosomes and lysosomes. Treatment of morulae with monensin was associated with swelling of Golgi compartments in addition to altering the morphology of mitochondria, lysosomes and the plasma membrane. BFA, and to a lesser extent monensin, inhibited cytokinesis as evidenced by the detection of binucleate blastomeres. In addition, BFA induced morulae to decompact. These latter effects have not been reported previously for these agents in mammalian somatic cell lines or other vertebrate or invertebrate embryos. These results provide the first demonstration of the structural effects of BFA and monensin on cells of the early mammalian embryo, some of which are consistent with the known actions of these agents on components of the vesicular protein trafficking system in mammalian somatic cells. This information serves as a foundation for the further use of these agents in studies of vesicular protein trafficking as an agent of preimplantation morphogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050081
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  • 6
    Electronic Resource
    Electronic Resource
    The anatomy of bone sialoprotein immunoreactive sites in bone as revealed by combined ultrastructural histochemistry and immunohistochemistry (1995)
    Springer
    Calcified tissue international 57 (1995), S. 277-284 
    Details
    ISSN: 1432-0827
    Keywords: Bone sialoprotein ; osteoblast ; Bone matrix ; Electron microscopy ; Immunolocalization ; noncollagenous protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone sialoprotein was immunolocalized at the EM level in thin Lowicryl K4M sections of rat bone. Because of the unconventional EM morphology of the bone matrix seen in thin demineralized acrylate sections, the pattern of immunolabeling was compared with detailed structural images of demineralized bone obtained using an en bloc treatment of tissue samples with the cationic electron ‘dye’, Malachite Green (MG), which provides stabilization and retention of anionic material throughout specimen processing. A system of structures corresponding to the sites of bone sialoprotein (BSP) immunoreactivity, as seen in Lowicryl K4M thin sections, could be readily identified in the MG-treated, expoxy thin sections. This system includes the cement lines, and aggregates of similar material within mineralized bone and mineralizing osteoid. The virtual identity of BSP distribution with the arrangement of the MG-visualized material indicates that a BSP-enriched, noncollagenous phase can be demonstrated using different, unrelated tissue preparation and imaging protocols for EM. Besides improving our understanding of the distribution of bone sialoprotein in bone, these data assign a previously unrecognized structural dimension to noncollagenous material in the bone matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298883
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  • 7
    Electronic Resource
    Electronic Resource
    An ultrastructural evaluation of the effects of cysteine-proteinase inhibitors on osteoclastic resorptive functions (1995)
    Springer
    Calcified tissue international 56 (1995), S. 566-570 
    Details
    ISSN: 1432-0827
    Keywords: Cathepsin inhibitors ; Osteoclasts ; Resorption ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract This study was designed to evaluate the effects of specific and potent cathepsin inhibitors on osteoclastic resorptive functions in vitro by means of a novel ultrastructural assay system. Mouse bone marrow cell-derived osteoclasts were suspended on dentine slices and cultured for 48 hours in the presence of either E-64 (a generalized cysteine proteinase inhibitor) or Z-Phe-Phe-CHN2 (a selective cathepsin L inhibitor). After the removal of cultured osteoclasts, co-cultured dentine slices were examined using electron microscopy: backscattered (BSEM), scanning (SEM), and atomic force (AFM). In morphometric analyses of BSEM images, there were no significant differences in the areas of demineralized dentine surfaces between control and inhibitor-treated groups, suggesting that cathepsin inhibitors had no effect on dentine demineralization by cultured osteoclasts. However, in SEM and AFM observations, both inhibitors remarkably reduced to the same extent, the formation of deep resorption lacunae on dentine slices that had resulted from degradation of matrix collagen. In addition, Z-Phe-Phe-CHN2 treatment produced deeper, ring-like grooves with little collagen exposure in shallow resorption lacunae. These results strongly suggest that (1) cathepsins released by osteoclasts are involved in the formation of deep resorption lacunae, and (2) cathepsin L plays a key role in bone resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298591
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  • 8
    Electronic Resource
    Electronic Resource
    Bimodal solubilization of phospholipid-cholesterol vesicles in 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) solutions. Formation of filamentous and helical microstructures depends on negatively charged lipids (1996)
    Springer
    European biophysics journal 25 (1996), S. 67-73 
    Details
    ISSN: 1432-1017
    Keywords: Key words Gallstone ; Cholesterol monohydrate crystals ; Phase separation ; Light scattering ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Phospholipid/cholesterol vesicles were solu-bilized by 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). Above 30 mol% cholesterol (Ch) in the lipid vesicles several remarkable changes of the solubilization process were observed. (i) Two modes of solubilization: The effective detergent to lipid ratio Rc(M) for the formation of mixed micelles decreased from Rc(M) = 43 ± 3 at low lipid concentrations, [L]≤ 0.15 mm, to Rc(M) = 2.4 ± 0.3 above [L] = 0.5 mm (40 mol% Ch, T = 20 °C). (ii) At subsolubilizing CHAPS concentrations, filamentous and helical microstructures were formed, similar to those which were observed in native and model bile. (iii) The number of observed fibers was about two orders of magnitude higher in the presence of the negatively charged lipids phosphatidylglycerol (PG) and phosphatidic acid (PA) compared to the zwitterionic phosphatidylcholine (PC). Fiber formation began after 16–18 h using PG and PA compared to 3–4 days in the presence of PC. Screening of the charged lipids by NaCl effectively reduced the formation of fibers. Assuming binding of Na+ to the charged lipid aggregates, an intrinsic binding constant Kint = 0.6 M–1 was determined by applying the Gouy-Chapman theory. After the addition of CHAPS to PG/Ch vesicles, a fast initial solubilization of the vesicles (〈1 min) to mixed micelles (rh = 2.3 ± 0.2 nm) and small vesicles (rh = 23 ± 1 nm) was observed, followed by an intermediate period of 2 h, after which the formation of fibers occurred (〉15 h). The microstructures are visualized by darkfield and electron microscopy. The method of vesicle solubilization is compared to the dilution of concentrated micellar solutions, which is usually applied to model bile systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050019
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  • 9
    Electronic Resource
    Electronic Resource
    Magnetic properties of human liver and brain ferritin (1999)
    Springer
    European biophysics journal 28 (1999), S. 263-267 
    Details
    ISSN: 1432-1017
    Keywords: Key words Human liver ; Human brain ; Ferritin ; Electron microscopy ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Human brain (globus pallidus) and liver tissues were investigated by means of electron microscopy (EM), Mössbauer spectroscopy (MS) and SQUID magnetometry techniques. Based on MS measurements, the iron present was identified to be in the ferritin-like form (61–88%) and in the form of a low-spin iron species (the balance). Its overall concentration was estimated as 1.5(3) mg in the brain and 2.4(5) mg in the liver, per gram of lyophilized tissue. The average core diameter was determined by EM measurements to be equal to 7.5(1.3) nm for the liver and 3.3(5) nm for the brain. Magnetization measurements carried out between 5 and 300 K yielded an estimation of an average blocking temperature, KT BL, as equal to 6.7 K and 8.5 K for the liver and the brain, respectively. From the dependence of KT BL on the external magnetic field it was concluded that the ferritin-like cores in the studied samples can be regarded as non-interacting particles. Finally, the uniaxial magnetic anisotropy constant was determined to be 6×103 J/m3 for the liver and 4×104 J/m3 for the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050208
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  • 10
    Electronic Resource
    Electronic Resource
    Endophytic establishment of Azorhizobium caulinodans through auxin-induced root tumors of rice (Oryza sativa L.) (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 293-302 
    Details
    ISSN: 1432-0789
    Keywords: Key words Ammonium excretion ; Azorhizobium caulinodans ; Auxine ; 2 ; 4-Dichlor-phenoxy-acetic acid ; Nitrogen fixation ; Paranodulation ; Rice ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rice seedlings developed nodule-like tumors (para-nodules) along primary and secondary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Histologically, these tumors appeared as cancerous out-grown lateral-root primordes and were thus comparable with stem nodules of the legume Sesbania rostrata. Azorhizobium caulinodans (a diazotroph known as a specific endophyte of Sesbania rostrata) was introduced and became established inside rice para-nodules and in root tissues around tumor bases. The infection with A. caulinodans followed a typical “crack-entry” invasion at places where para-nodule tumors had emerged through the root cortex and epidermis. The bacteria settled with high cell densities in intercellular spaces of the induced tumors and betwen root cortical cells. Infection of plant cells took place both in the epidermis and in cortical tissue. Intracellularly established A. caulinodans was found inside the cytoplasm, surrounded by membrane-like structures. N2 fixation by tumor-inhabiting Azorhizobium sp. was increased at low O2 tensions (1.5–3 kPa) compared with an untreated control. Only a little activity remained at O2 tensions of 5 kPa and above. The present results confirm that root-tumor induction offers a suitable method of establishing diazotrophs endophytically in the roots of gramineous crops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334906
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