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  • 1
    ISSN: 1432-2013
    Keywords: Human Bronchial Epithelial cells Hydroxyl radical Patch-clamp Chloride channel ORCC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Respiratory pathologies can result from the exposure of airway epithelial cells to oxidative stress. We studied the effects of the hydroxyl radical ⨰OH, for which there is no natural intra- or extracellular scavenger, on an outwardly rectifying chloride channel (ORCC). In the human bronchial cell line 16HBE14o–, the cytoplasmic side of ORCC in inside-out excised membrane patches was exposed to ⨰OH created by simultaneously superfusing Fe2+ and H2O2 in front of the patch-pipette. ORCC was activated by depolarizing voltage steps. Its open probability (P o) increased with bath [Ca2+] above 1 µM. Upon brief exposure to ⨰OH, ORCC first closed and then alternated between periods of closure and normal activity. The duration of closure increased with the duration of ⨰OH exposure but voltage steps could reopen the channel. After 10 min exposure to ⨰OH, however, the channel closed irreversibly, regardless of the number of subsequent voltage steps or the duration of washing. Low [Ca2+] in the bath accelerated the irreversible closure of the channel in the presence of ⨰OH. Intracellular application of ⨰OH progressively inhibited ORCC activity by inducing long closure periods that increased with time. This might have important pathophysiological implications in the process of inflammation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell biology and toxicology 12 (1996), S. 375-375 
    ISSN: 1573-6822
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 131-144 
    ISSN: 0148-7280
    Keywords: spermatozoa ; human ; motility ; activated motility ; hyperactivated motility ; capacitation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Ten frames/sec microcinematography (“film”), 1 second timed-exposure photomicrography (“photo”), and laser Doppler velocimetry (LDV) were used to analyse the swimming patterns of human spermatozoa after migration (1 h at 37°C) into an overlying layer of either BWW or Menezo's B2 media. The upper layer of medium was carefully removed and further incubated at 37°C for either 4 h (B2) or 5 h (BWW) and the sperm motility analysed again. Five experiments were performed using semen from different donors. Film and photo analyses gave the relative incidence of nonprogressive and progressively motile spermatozoa plus, for the progressive spermatozoa, the velocities of progression (Vp) and amplitudes of lateral head displacement (Ah). LDV gave the percentage of motile spermatozoa and the modal instantaneous velocity (Vm). All postmigration sperm populations showed large significant increases in the percentage of motile spermatozoa, with good survival during incubation. The progressive postmigration spermatozoa generally moved with greater Vp and Ah than in the initial seminal plasma-diluted material; Vm was also increased. There were further increases in both Vp and Ah during incubation, but no change in Vm was detected. While the majority of spermatozoa were progressive, some showed a highly active pattern of movement which resulted in no net forward progression. The possible homology between these spermatozoa and the “hyperactivated” motility of capacitated spermatozoa in other mammalian species is discussed. Apparent discrepancies between the three methods used for motility analysis were seen, the possible causes and significances of which are also discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 185-196 
    ISSN: 0148-7280
    Keywords: free radicals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Catalase activity was determined in human semen by measuring the oxygen burst with a Clark electrode, after H2O2 addition. Significant catalase activities (mean ± SD) were found in migrated, motile spermatozoa (44 ± 17 nmoles O2/min/108 cells) and in seminal plasma of normozoospermic men (129 ± 59 nmoles O2/min/ml). It has been demonstrated that seminal catalase originated from prostate; however, its activity was not correlated with the usual prostatic markers (such as citric acid and zinc). Our data suggest a multiglandular function secreted by this organ. The catalase activities measured in seminal samples from asthenozo-ospermic, infertile men were found lower than those from normozoospermic subjects. The understanding of the relative contribution of the different enzyme systems against O2 toxicity (superoxide dismutase, catalase, glutathione peroxidase) seem to be a priority area of research to understand disturbances of sperm function.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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