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  • 1
    Electronic Resource
    Electronic Resource
    Effect of photoperiod and acclimation temperature on nonshivering thermogenesis and GDP-binding of brown fat mitochondria in the Djungarian hamsterPhodopus s. sungorus (1989)
    Springer
    Pflügers Archiv 413 (1989), S. 667-672 
    Details
    ISSN: 1432-2013
    Keywords: Nonshivering thermogenesis ; Brown fat ; Uncoupling protein ; Mitochondria ; Noradrenaline ; Cytochrome c oxidase ; Cold acclimation ; Scatchard analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acclimation to short photoperiod at 23° C constantT a causedP. sungorus to improve their NST capacity from 752 to 1,082 mW. Chronic cold exposure in short photoperiod further enhanced the NST capacity, reaching a maximum level of 1,573 mW at −5° C acclimation temperature. Improvements in NST capacity were always accompanied by an increase in brown fat mitochondrial mass and GDP-binding of brown fat mitochondria, in proportion with the cold load applied during temperature acclimation (23°, 15°, 5°, −5° C). Brown fat mitochondrial protein increased from 7.41 mg (23° CT a, long photoperiod) through 21.6 mg (23° CT a, short photoperiod) and 81.6 mg (−5° CT a, short photoperiod). This ∼10-fold increase was accompanied by a ∼35-fold increase in GDP-binding (2.0, 7.3 and 71.6 nmol GDP bound, respectively), demonstrating that the increase in capacity for uncoupled respiration in brown fat is of primary significance for thermogenic acclimation to cold as well as to short photoperiod.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00581818
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  • 2
    Electronic Resource
    Electronic Resource
    Electrical injuries to the eye (1975)
    Springer
    Graefe's archive for clinical and experimental ophthalmology 193 (1975), S. 67-79 
    Details
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Einfluß von Wechselstromstößen auf das Kaninchenauge wurde untersucht. Die Versuchsanordnung wurde so gewählt, daß sowohl Einzel- als auch multiple Stromstöße von 0–600 V mit variabler Einwirkungszeit appliziert werden konnten. Der Strom wurde gemessen mit einem Tectronex- Storage- Oszilloskop. Die Versuche wurden an ausgewachsenen holländischen Kaninchen durchgeführt. Wenn die Kaninchenaugen einem Strom von 500 V für mindestens 250 Millisekunden und 400 Milliampère ausgesetzt wurden, zeigte sich bei einigen Tieren eine dauerhafte Herabsetzung der Höhe der b-Welle im Elektroretinogramm. Keine histologischen oder ophthalmoskopischen Veränderungen konnten in der Retina, im Nervus opticus oder in den Blutgefäßen mit den üblichen Untersuchungsmethoden festgestellt werden. Der Einfluß des elektrischen Stromes auf die Linse wurde ebenfalls studiert. Vorangegangene Untersuchungen zu diesem Problem benutzen vorwiegend eine Technik mit vielen Stromstößen, eine Situation, die bei Unfällen kaum auftreten dürfte. Die vorliegende Studie untersucht die Linsenschädigungen beim Kaninchenauge nach einzelnen Stromstößen von definierter elektrischer Intensität. Die biomikroskopischen Characteristica dieser Veränderungen werden beschrieben. Geringfügige Linsenveränderungen wurden bei einzelnen Stromstößen beobachtet, die von 6–26 Watt pro Sekunde reichten. Typische vordere Schalentrübungen wurden durch Stromstärken von 23–80 Watt pro Sekunde hervorgerufen. Die durchschnittliche Einwirkungszeit betrug 250 Millisekunden oder weniger, da sonst die Überlebenssrate zu gering war. 3 Patienten mit Starkstromverletzungen werden vorgestellt mit einer Übersicht der einschlägigen Literatur.
    Notes: Summary The effect of electric current on the eyes of experimental animals was studied. An apparatus was constructed to allow single and multiple shock exposures from 0 to 600 volts at variable exposure times. The current was measured on a Tectronex Storage Oscilloscope. Mature Dutch rabbits were used as experimental animals. When rabbit eyes were subjected to a current of 500 volts for no less than 250 milliseconds and 400 milliamperes or more, a permanent decrease in the amplitude of the b-wave of the Electroretinogram resulted in some animals. No histological or ophthalmological alterations in the retina, optic nerve or vasculature could be observed using conventional techniques. The cataractogenic properties of electric current were also studied. Most previous observations dealing with this subject utilized a multiple shock technique-something which is unlikely to occur in any accidental exposure. This study focussed on the production of lens changes in rabbit eyes following single exposures of measured electric current. The biomicroscopic characteristics of these changes were described. Minimal lens changes were produced by single shock exposures ranging from 6 to 26 watts per second while typical electrical anterior subcapsular cataracts were produced by current of 23 to 80 watts per second. Exposure times were mostly 250 milliseconds or less since the survival rate of animals subjected to longer exposures made such studies unfeasible. Three patients with electrical injuries were presented and some of the pertinent literature was reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410527
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  • 3
    Electronic Resource
    Electronic Resource
    Potent gene regulatory and antiproliferative activities of 20-methyl analogues of 1,25 dihydroxyvitamin D3 (1996)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 199-206 
    Details
    ISSN: 0730-2312
    Keywords: regulation of transcription ; control of proliferation ; vitamin D3 analogues ; vitamin D3 receptor ; limited protease digestion assay ; lymphocytes ; breast cancer cells ; promoter selectivity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The biological active form of vitamin D3, 1,25-dihydroxyvitamin D3 (VD), regulates cellular growth and differentiation. This provides the hormone with an interesting therapeutic potential. However, hypercalcemia is a side effect, which is caused by VD's classical action, the regulation of calcium homeostasis. This made the need for VD analogues with selectively increased cell regulatory properties. Studies with 20-epi analogues pointed out the importance of the carbon-20 position and led to the development of 20-methyl derivatives of VD. In this report the biological properties of the compounds ZK161422 and ZK157202, which are 20-methyl- and 20-methyl-23-eneanalogues, respectively, have been analyzed in comparison with VD. Both compounds show about 2-fold lower affinity to the VD receptor (VDR) than VD. However, compared to VD, their antiproliferative effect is up to 30-fold higher on human peripheral blood mononuclear cells and even up to 300-fold higher on human breast cancer MCF-7 cells. Whereas the hypercalcemic effect for ZK157202 is also increased 10-fold, ZK161422 has the same calcium-mobilizing potency as VD. Moreover, ZK161422, but not ZK157202, showed preference for gene activation from a promoter carrying a VD response element with a palindromic arrangement of two hexameric receptor binding sites spaced by 9 nucleotides (IP9) rather than for activation from a response element formed by a direct repeat spaced by 3 nucleotides (DR3). This observation supports a model, in which promoter selectivity reflects the selectively increased antiproliferative effect of VD analogues. © 1996 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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