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  • 1
    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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  • 2
    ISSN: 1432-0533
    Keywords: Carbon monoxide encephalopathy ; Selective topography of CNS lesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experimental studies were performed to elucidate the significance of various physiological factors contributing to the pathogenesis of carbon monoxide (CO) encephalopathy, such as systemic blood pressure (BP), common carotid artery blood flow (CF), local blood flow (LBF) of the brain and blood gas including pH, and to analyse the morphological character of the cerebral white matter lesions in the acute phases with light and electron microscopes; 14 adult cats were exposed to 0.3% CO/air gas under respiratory control for 1 h and 17 min to 2 h and 50 min and killed 1.5 h to 3 weeks later. During the 1st h the CF and LBF increased along with the concentration of CO haemoglobin and the BP showed slight decrease in all the CO-exposed cats. After the 1st h, the BP dropped progressively as well as the CF and LBF. The LBF of the cortex and white matter changed in parallel, but often that of the latter approximated or exceeded that of the former in the cerebrum. During CO exposure, acidosis occurred in all the cats and haemoconcentration resulted in almost all of the cats. In all the cats except one which showed the least BP drop, lesions occurred selectively in the cerebral white matter and in six or seven cats focal coagulation necrosis or ischaemic changes occurred in the nerve cells in the bilateral pallidum, substantia nigra, and hippocampus similar to human patients. The cerebral white matter lesions were suggestive of those caused by circulatory disturbance. The severity of the white matter damage showed a good positive correlation with the intensity of the BP drop, but not with other factors, such as the duration of CO-exposure, CO-haemoglobin level, acidosis, or haemoconcentration. On the basis of such physiological and morphological findings, we have found the following to be essential for the selective damage of the cerebral white matter rather than the cerebral cortex or white matter of other regions of the CNS: (1) the coexistence of the initial phase of increase in and the succeeding decrease in the cerebral blood flow and (2) the anatomical finding that the cerebral white matter is supplied by its own long nourishing arteries with small amounts of capillary beds and a thinner media compared with that of the subarach-noidal artery.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We attempted to determine wheter all cases of AWTA (anirida-Wilms tumor association) or any of the following groups of patients show 11p deletion: cases of Wilms tumor with congenital abnormalities other than aniridia, those without any congenital abnormalities, tumor itself in cases of Wilsm tumor without constitutional 11p deletion and cases of aniridia or hemihypertrophy without Wilms tumor. We studied a total of 29 index patients including five cases of AWTA, four cases of Wilms tumor with various congenital abnormalities, 16 cases of Wilms tumor without other abnormalities, three cases of aniridia in one of which Wilms tumor developed later and a case of hemihypertrophy. In all five cases of AWTA and in a case of aniridia who later developed Wilms tumor, 11p deletion involving the p13 band was detected. The mother of the latter also showed an identical 11p deletion. The common segment of deletion was the middle part of the p13. Two possible hypotheses on the mechanism through which Wilms tumor might develop were evaluated, based on the distribution of break points. All other cases, including five with tumor culture, showed a normal karyotype.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 54 (1984), S. 111-113 
    ISSN: 1432-1246
    Keywords: 1,2-dichloroethane ; Lactate ; Ammonia ; Ornithine carbamyl transferase ; m-GOT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is a case report of acute fatal intoxication after accidental exposure to 1,2-dichloroethane in a 51-year-old man. Clinical manifestations, blood chemistry, and autopsy findings are described. High levels of lactate and ammonia in blood had been observed before the elevation of glutamic transaminases, lactic dehydrogenase, and creatine phosphokinase. Ornithine carbamyl transferase and glutamic oxaloacetic transaminase of mitochondrial origin (m-GOT) were remarkably high.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1335
    Keywords: SEM observation ; Rat nasal cavity tumors ; Periodical observation ; 1,4-Dinitrosopiperazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Epithelial lesions in the nasal cavity of male F344 rats appeared as papillary and nodular hyperplasias progressing to invasive carcinomas during administration of 1,4-dinitrosopepirazine (DNP) at a dose of 0.01% in the drinking water. Observations with specific attention to the cells covering the luminal surface of the mucosa were made by scanning electron microscopy at 10-week intervals. After administration of DNP for 20 and 30 weeks three different types of light microscopically identifiable focal lesions, i.e., papillary hyperplasia, nodular hyperplasia and papilloma, of the epithelium in the nasal cavity were distinguished, and after 40 and 50 weeks areas of squamous cell carcinomas were also observed. In the scanning electron microscope, papillary hyperplasia appeared as a nodular elevation of the surface with a smoother appearance than the surrounding nonnodular areas. Areas of nodular (inverted) hyperplasias had irregularly shaped indentions of the surface. Papillomas appeared as pedunculated projections of the surface. Carcinoma presented as a protrusion of irregular cell masses. The surface cells in the areas of papillary and nodular hyperplasias and of papilloma had numerous short microvilli rather uniform in shape (short-uniform microvilli), unlike the normal epithelium in the nasal cavity, which possesses cilia or olfactory vesicles. The microvilli of carcinoma cells were more irregular in shape and size than those of hyperplastic cells (pleomorphic microvilli).
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 106 (1981), S. 259-268 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Parathyroid hormone (PTH) greatly increased the level of adenosine 3′,5′ cyclic monophosphate (cAMP) in rabbit costal chondrocytes in culture 2 minutes after its addition. PTH, as well as N6 O2' dibutyryl adenosine 3′,5′ cyclic monophosphate (DBcAMP) and 8 Bromo adenosine 3′,5′ cyclic monophosphate (8 Br-cAMP) induced ornithine decarboxylase (ODC; L-ornithine carboxylyase; EC 4.1.1.17), which reached a maximum 4 hours after their addition. Neither cAMP, N6 O2′ dibutyryl guanosine 3′,5′ cyclic monophosphate (DBcGMP), nor sodium butyrate increased the activity of the enzyme. PTH had no effect on DNA synthesis, while DBcAMP and 8 Br-cAMP decreased DNA synthesis. Expression of the differentiated phenotype of chondrocytes in culture was also induced by PTH, DBcAMP, and 8 Br-cAMP, but not by cAMP, DBcGMP, or sodium butyrate, as judged by morphological change. Glycosaminoglycan synthesis, a characteristic of the cartilage phenotype, began to increase 8 hours after addition of PTH or DBcAMP, reaching a plateau 32 hours after their addition.These findings suggest that PTH induces increase of ODC activity and expression of the differentiated phenotype of chondrocytes through increase of cAMP and that induction of ODC is closely related to expression of the differentiated phenotype of chondrocytes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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