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  • 1
    ISSN: 1432-0533
    Keywords: Cyanide encephalopathy ; Selective white matter lesion ; Cerebral local blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A study was performed to elucidate the significance of various physiological factors contributing to the pathogenesis of experimental cyanide encephalopathy, such as the systemic arterial blood pressure, venous pressure, common carotid blood flow and local blood flow of the cerebral grey and white matters, and blood gas including pH. The histology and topography of the brain damage was also analysed. Twenty-one cats were divided into four groups. The animals in groups 1, 2 and 3 were subjected to continuous infusion of 0.2% sodium cyanide solution and to the ensuing hypotension below 100 mm Hg by administering a ganglion-blocking drug and by respiratory arrest. Severe damage developed in the deep cerebral white matter, corpus callosum, pallidum and substantia nigra, but the damage of the cerebral cortex and hippocampus was not remarkable. The animals in group 4 that were subjected to cyanide infusion without significant hypotension (above 100 mm Hg), but to the same degree of acidosis as that of the the other groups, had similar morphological changes, but to a lesser degree. On the basis of our physiological and morphological findings, we speculated that the pathophysiological factors of tissue hypoxia and subsequent hypotension operated in cyanide leucoencephalopathy. The topographic selectivity seemed to be related to the characteristic cerebral vascular system, and the severity of the white matter lesions was related to the intensity of both hypoxia and hypotension during cyanide infusion, but not to the extent of acidosis, total dose of cyanide or duration of its infusion per se.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0533
    Keywords: Carbon monoxide encephalopathy ; Nitrogen hypoxia ; Selective white matter lesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Since in a previous study hypoxia and subsequent hypotension were considered to be essential for the pathogenesis of carbon monoxide encephalopathy (CO-encephalopathy), experiments were conducted to see whether a combination of nitrogen hypoxia and subsequent systemic hypotension of similar degree and duration as in the previous experimental CO poisoning could induce the same lesion in the CNS of cats. The partial pressure of blood oxygen was reduced to less than 26 mm Hg by increasing the concentration of nitrogen in N2/O2 gas to be inhaled in 1.5 h and then the aortic blood pressure (BP) was reduced to 60–80 mm Hg by blood depletion and ganglion-blockage for 1 h. In 11 of the 15 cats, lesions were produced in the CNS which were similar by light and electron microscopy to those in CO-encephalopathy. In control groups which were treated by hypoxemia only, hypotension only or a combination of CO2-gas inhalation and hypotension without hypoxemia, such lesions were not found in the cerebral white matter. Considering the pathogenesis of lesions in the cerebral white matter in both nitrogen hypoxia and CO-poisoning, two factors, i.e., hypoxemia and subsequent systemic hypotension, are common and essential. Further, the enormous vasodilation in the cerebral white matter induced by hypoxemia and subsequent drop in BP seem to cause a more severe circulatory disturbance in the cerebral white matter than in the cortex.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-203X
    Keywords: Key words Somaclonal variation ; Allium cyaneum ; Fluorescence in situ hybridization ; Autotetraploid regenerants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Investigations were performed to confirm the optimal in vitro culture condition for callus induction and plant regeneration, to observe if somoclonal variation occurs among regenerated plants at the ploidy level and to analyse the chromosomal location of 5S and 18S-26S rRNA gene families using fluorescence in situ hybridization in callus-derived plants of Allium cyaneum. High-est callus initiation was achieved with bulb explants cultured on MS medium supplemented with 2,4-D and BAP at 1 mg l–1 each. A total of 195 plants was obtained when using MS medium supplemented with 1 mg l–1 NAA and 5 mg l–1 BAP; about 92% were diploid having 2n=16; 8% showed a variation in ploidy level. Using digoxigenin-labelled 5S rRNA and biotin-labelled 18S-26S rRNA gene probes, we compared the fluorescence in situ hybridization patterns of autotetraploid plants with the A. cyaneum wild type. The 5S rRNA gene sites were detected on the interstitial region in the short arm of chromosome 4 and on the interstitial region in both arms of chromosome 7. The 18S-26S rRNA gene sites were detected on the terminal region of the short arm, including the satellite of chromosome 5, as well as on a part of chromosome B. The chromosomal location of both rRNA genes in regenerated autotetraploid plants corresponded to those of the wild species.
    Type of Medium: Electronic Resource
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