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Digitale Medien

Three-dimensional bend propagation in hamster sperm models and the direction of roll in free-swimming cells (1984)

Yeung, Ching-Hei ; Woolley, David M.

New York, NY : Wiley-Blackwell

Cell Motility and the Cytoskeleton 4 (1984), S. 215-226

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Details

ISSN: 0886-1544

Schlagwort(e): sperm motility ; flagellum ; axoneme ; microscopy ; Life and Medical Sciences ; Cell & Developmental Biology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Biologie , Medizin

Notizen: Iontophoretic application of ATP to the flagellum of the demembranated hamster spermatozoon produced a planar pair of bends at the two ends of the stimulated site. During bend propagation, torsion appeared in the vicinity of the interbend in some responses such that the distal bend was twisted clockwise when viewed from the base of the flagellum. This pattern of propagation is consistent with the instantaneous configurations of free-swimming cells previously described. The technique used here establishes that the three dimensionality arises from propagation per se, and does not depend on forces developed during swimming. The rolling of both free-swimming intact and demembranated spermatozoa was examined by two-color darkground videomicroscopy and the direction of rotation was, as predicted, always anticlockwise. A hypothetical mechanism, involving differential speeds of propagation of active sliding within the active microtubule subset, is proposed to account for the observed waveforms.

Zusätzliches Material: 7 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/cm.970040306

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Digitale Medien

Production of reactive oxygen species by and hydrogen peroxide scavenging activity of spermatozoa in an IVF program (1996)

Yeung, Ching-Hei ; Geyter, Christian ; Geyter, Maria ; [weitere]

Springer

Journal of assisted reproduction and genetics 13 (1996), S. 495-500

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ISSN: 1573-7330

Schlagwort(e): catalase ; fertilization ; reactive oxygen species ; scavenging activity ; sperm function

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Purpose: Reactive oxygen species (ROS) including H2O2 produced by spermatozoa have been suggested, on one hand, to be associated with idiopathic male infertility and, on the other hand, to stimulate certain sperm function leading to fertilization. The influence of ROS on fertilization was investigated in 75 IVF patients by correlating fertilization rates with the production of ROS and the H2O2-scavenging activity of swim-up spermatozoa prepared in parallel with the IVF samples. Results: Low rates of ROS production by the swim-up sperm was detected by the luminol-dependent chemiluminescence assay. They were not correlated with fertilization rates. The hydrogen peroxide scavenging capacity of these spermatozoa, measured as the removal of exogenous H2O2 assayed spectrophotometrically, decreased stepwise in groups of patients achieving higher fertilization rates, suggesting a positive effect of this ROS on fertilization. An alternative explanation of this correlation is plausible in view of the association of both high scavenging activities and poor fertilization rates with poor sperm morphology. Conclusions: ROS produced by spermatozoa selected by swim-up plays no negative, if not a positive, role in fertilization.