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  • Scanning electron microscopy  (111)
  • man  (90)
  • Springer  (201)
  • American Geophysical Union
  • Blackwell Publishing Ltd
  • Cell Press
  • Institute of Physics
  • Nature Publishing Group
  • 2005-2009
  • 1975-1979  (134)
  • 1970-1974  (67)
  • 1935-1939
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  • Springer  (201)
  • American Geophysical Union
  • Blackwell Publishing Ltd
  • Cell Press
  • Institute of Physics
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  • 1
    Electronic Resource
    Electronic Resource
    SEM analysis of amphibian mesodermal migration (1977)
    Springer
    Development genes and evolution 181 (1977), S. 31-40 
    Details
    ISSN: 1432-041X
    Keywords: Cell migration ; Mesoderm ; Gastrulation ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At the end of gastrulation, the lateral mesoderm of amphibian embryos migrates ventrally between the ectoderm and the endoderm. The present study is an examination of the morphology of the leading cells of the mesodermal sheet and of the substratum over which they move (the inner surface of the ectoderm). The cells of the leading edge of the mesoderm are generally round, with very short and narrow flattened projections in the forward direction. These projections do not have a “ruffled” morphology, regardless of whether fixation is carried out before or after the ectoderm and mesoderm are dissected away from the endoderm. The inner surface of the ectoderm is covered with fine (450–500A) filamentous extracellular material and the ectoderm cells sometimes extend cytoplasmic processes (approx. 0.1 μ wide) onto the leading surface of the mesoderm or onto adjacent ectoderm cells. These studies indicate that the morphology of cell migration in amphibians is closer to that seen inFundulus than to that characteristic of chick or mammalian cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857266
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  • 2
    Electronic Resource
    Electronic Resource
    Growth of embryonic chick tibiae in ovo and in vitro: A scanning electron microscope study (1979)
    Springer
    Calcified tissue international 27 (1979), S. 33-40 
    Details
    ISSN: 1432-0827
    Keywords: Chick embryo ; Bone ; Organ culture ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The study describes the ultrastructure of the mineralized portion of chick tibiae from 10 days in ovo to 2 days post-hatch. At 10 days a single mineralized cylinder surrounds the diaphysis. On its outer surface columnar trabeculae join to form ridges parallel to the long axis of the bone. These ridges are covered by another cylinder and form the haversian canals. At 11 days vascular invasion of the marrow cavity occurs and resorption of the endosteal surface begins. This type of periosteal deposition and endosteal resorption is repeated during and subsequent to embryonic development. The mineralized portion of 10-day chick tibiae cultured for 2 days in modified BGJ medium was compared with 10-, 11-, and 12-day tibiae in ovo. Cultured tibiae were similar in length and calcium content to 11-day tibiae in ovo. The form of mineral deposited in ovo and in culture was the same, namely, aggregates of spherical mineral clusters. Differences in culture included the following: (a) few concentric cylinders were deposited as compared with tibiae in ovo; (b) trabeculae were not arranged in rows and ridges in culture; (c) osteocytic lacunae were restricted to bases of trabeculae rather than uniformly distributed as in ovo; and (d) the endosteal surface of tibiae in culture appeared etched.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441158
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  • 3
    Electronic Resource
    Electronic Resource
    Correlation of freeze-fracture and scanning electron microscopy of epiphyseal chondrocytes (1978)
    Springer
    Calcified tissue international 26 (1978), S. 237-241 
    Details
    ISSN: 1432-0827
    Keywords: Epiphyseal chondrocytes ; Freezefracture ; Scanning electron microscopy ; Cell processes ; Membrane particles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 μm diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013264
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  • 4
    Electronic Resource
    Electronic Resource
    Scanning electron microscopical study on the fluorosis of enamel in rats (1978)
    Springer
    Calcified tissue international 25 (1978), S. 75-83 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010754
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  • 5
    Electronic Resource
    Electronic Resource
    Structure and association of wall fibrils produced by regenerating tobacco protoplasts (1979)
    Springer
    Planta 146 (1979), S. 203-210 
    Details
    ISSN: 1432-2048
    Keywords: Cellulose ; Microfibrils ; Negative staining ; Nicotiana ; Protoplasts ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study has been made of the wall fibrils produced by tobacco protoplasts, using scanning electron microscopy in conjunction with negative staining. It has been shown that the fibres seen in scanning electron microscopy correspond to aggregates of microfibrils. These aggregates are only visible where they are lifted clear of the protoplast surface. Negative staining of fixed protoplasts shows that the aggregation of microfibrils into the fibres visible in scanning electron microscopy is probably produced by air-drying. Gentle disruption of microfibrils produces both random broken fragments and bundles of short pieces of fibrillar material about 60 nm in length. This material is present in undisrupted young walls, but not in undisrupted older walls. The microfibrils in young walls seem much more fragile and liable to breakage than those in older walls. These results are discussed in terms of the interpretation of scanning electron microscope images and the mechanism of cellulose microfibril formation by higher plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388233
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  • 6
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of desmethylimipramine and nortriptyline in man after single and multiple oral doses — A cross-over study (1972)
    Springer
    European journal of clinical pharmacology 5 (1972), S. 1-10 
    Details
    ISSN: 1432-1041
    Keywords: Tricyclic antidepressants ; desmethylimipramine ; nortriptyline ; single- and multiple-dose kinetics ; plasma concentration ; plasma clearance ; pharmacogenetics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Eight healthy volunteers received single oral doses (1 mg/kg) and 6 received multiple doses (0.4 mg/kg t.i.d. for 2 weeks) of desmethylimipramine (DMI) and nortriptyline (NT) on different occasions. Kinetic analysis of plasma levels of the drugs showed that the ratios between single-dose peak-levels, plasma half-lives and apparent mean “steady-state” plasma levels of the two drugs were constant in all the subjects, and averaged 0.6. Despite their closely related chemical structures the apparent plasma clearance rate of DMI was about twice that of NT, and this might be associated with their different degrees of binding to plasma proteins. — The “steady-state” plasma level of NT in man is known to be genetically determined, and the conformity within each individual of the plasma clearance rates of DMI and NT indicates that the plasma kinetics of both these drugs are controlled by common genetic factors. — The study also shows that the “steady-state” plasma level of DMI, like that of NT, can be predicted accurately from single-dose plasma-level data. Thus, if the kinetic characteristics of one of these drugs in a subject are known, it is possible to predict the plasma kinetics of the other compound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00560888
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  • 7
    Electronic Resource
    Electronic Resource
    Pharmacological effects and serum levels of orally administered alprenolol in man (1972)
    Springer
    European journal of clinical pharmacology 5 (1972), S. 44-52 
    Details
    ISSN: 1432-1041
    Keywords: alprenolol ; serum drug level ; exercise ; man ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of alprenolol on heart rate and systolic blood pressure were studied in healthy subjects during standardized exercise on a bicycle ergometer. In one series of experiments, in which serum concentrations of alprenolol were also measured, the effects of single oral doses of 50, 100 and 200 mg of alprenolol and a placebo were compared by a double blind cross-over technique. In a second series of experiments 100 mg alprenolol was given four times in one day and the effect was followed for up to eighteen hours after the last dose. — Alprenolol diminished the expected increase in heart rate and systolic blood pressure during exercise. The reduction of exercise tachycardia in a given individual was linearly related to the logarithm of the dose or the serum concentration of alprenolol. The serum concentrations required for a given reduction of exercise tachycardia varied almost one hundred-fold amongst the subjects studied. The biological availability of alprenolol was dose-dependent, probably due to a limited capacity biotransformation of the drug before it entered the general circulation. After a single dose the serum level of alprenolol and its chronotropic effect diminished at a rate corresponding to an elimination half life of about two hours. This rate of elimination was consistent with that calculated from the results of the four dose study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00560895
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  • 8
    Electronic Resource
    Electronic Resource
    Urinary excretion of nortriptyline and five of its metabolites in man after single and multiple oral doses (1973)
    Springer
    European journal of clinical pharmacology 5 (1973), S. 174-180 
    Details
    ISSN: 1432-1041
    Keywords: Tricyclic antidepressant ; nortriptyline ; metabolism ; urine ; pharmacokinetics ; twins ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The urinary excretion of nortriptyline (NT) and five of its metabolites was studied by quantitative gas chromatography in 22 twins and 7 unrelated healthy subjects after single (1 mg/kg) and multiple oral doses (0.4 mg/kg t.i.d.) of NT hydrochloride. A mean recovery of 62% of the dose was found after both single and multiple doses. The metabolite pattern in the urine was qualitatively and quantitatively identical in the two regimes, but there were marked variations in the pattern of metabolites between individuals. The disappearance rate of NT from the plasma was mainly determined by the metabolism of NT to 10-hydroxynortriptyline, which varied considerably between individuals. The data suggest that in certain rapid NT metabolizers, the upper limit for the overall clearance of NT from the plasma (if extrahepatic metabolism is assumed to be negligible) might be set by the blood flow through the liver.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00564899
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  • 9
    Electronic Resource
    Electronic Resource
    The availability of orally administered nortriptyline (1973)
    Springer
    European journal of clinical pharmacology 5 (1973), S. 181-185 
    Details
    ISSN: 1432-1041
    Keywords: Tricyclic antidepressant ; nortriptyline ; single-dose kinetics ; plasma/blood concentrations ; metabolites ; absorption ; availability ; apparent volume of distribution ; plasma/blood clearances ; gas chromatography-mass spectrometry ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The availability of an orally administered drug may be defined as the fraction of the total dose that enters the blood. Three healthy subjects were given identical doses of nortriptyline hydrochloride (NT-HCl) by the oral and intramuscular routes. The availability was assessed by comparing the total areas under the NT plasma concentration-time curves produced by the two methods of administration. The concentrations of NT in plasma and blood were determined by gas chromatography — mass spectrometry and were found to be almost identical. The observed availability of NT in these subjects ranged between 56 and 70% (mean 64%). The availability predicted from the parenteral plasma levels (assuming an average hepatic blood flow of 1.7 l/min) differed from the observed availability in one subject, perhaps because of the known variation in liver blood flow between individuals. The gastrointestinal absorption of NT-HCl was complete, since the recovery of the main metabolite, 10-hydroxynortriptyline, was the same after the two routes of administration. Pharmacokinetic analysis of the data showed that there might exist interindividual differences in the apparent volume of distribution of NT, (Vd)β. There was no apparent relationship between the variations in availability of NT and “steady-state” plasma levels or the disposition plasma half-lives of the drug. The calculated (Vd)β and (t 1/2)β of NT for each subject were in good agreement with those obtained from a previous study of single oral does of NT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00564900
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  • 10
    Electronic Resource
    Electronic Resource
    Fate of the analgesic and anti-inflammatory drug K 4277 after oral administration to man (1973)
    Springer
    European journal of clinical pharmacology 6 (1973), S. 256-260 
    Details
    ISSN: 1432-1041
    Keywords: K 4277 ; anti-inflammatory agents ; metabolism ; man ; oral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The fate of the new analgesic and anti-inflammatory agent α-[4-(1-oxo-2-iso-indolinyl)-phenyl]-propionic acid (compound K 4277) in healthy volunteers has been investigated by a radio-isotope method and gas-liquid chromatography. After oral administration, the drug was absorbed rapidly and completely and occurred in plasma mainly as unchanged compound bound extensively to plasma proteins. Its disappearance from plasma followed at least a bi-exponential function and was almost complete in 24 to 48 h. Most of the drug is excreted in urine as a glucuronide and a lesser amount as the unchanged compound. There were only negligible amounts of other metabolites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644742
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