R
Roelof Menkveld
Researcher at Stellenbosch University
Publications - 97
Citations - 6355
Roelof Menkveld is an academic researcher from Stellenbosch University. The author has contributed to research in topics: Sperm & Semen analysis. The author has an hindex of 37, co-authored 96 publications receiving 5990 citations. Previous affiliations of Roelof Menkveld include Eastern Virginia Medical School & Tygerberg Hospital.
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Journal ArticleDOI
Sperm morphologic features as a prognostic factor in in vitro fertilization.
Thinus F. Kruger,Roelof Menkveld,F. S. H. Stander,Carl Lombard,Jacobus P. Van der Merwe,Johannes A. van Zyl,Karen Smith +6 more
TL;DR: In this article, the authors conducted a prospective study in women with bilateral tubal damage to determine whether there is a prognostic value in the percentage normal sperm morphologic features in a human in vitro fertilization (IVF) program.
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The evaluation of morphological characteristics of human spermatozoa according to stricter criteria
TL;DR: It can be concluded that the method developed in the laboratory and which resulted in the use of stricter criteria for the evaluation of sperm morphology is a practical, reliable and repeatable method and has a good prognostic value for the prediction of expected IVF fertilization, the hamster test and hemizona assay.
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Influence of deoxyribonucleic acid damage on fertilization and pregnancy
Ralf Henkel,Marjam Hajimohammad,T. Stalf,Christiaan F. Hoogendijk,Claas Mehnert,Roelof Menkveld,H. Gips,Wolf-Bernhard Schill,Thinus F. Kruger +8 more
TL;DR: The data clearly demonstrate that DNA fragmentation, as determined by the TUNEL assay, is predictive for pregnancy in IVF, which implies that spermatozoa with DNA fragmentation can still fertilize an oocyte but that when paternal genes are "switched on," further embryonic development stops, resulting in failed pregnancy.
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Effects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial.
Wai Yee Wong,Hans M.W.M. Merkus,Chris M.G. Thomas,Roelof Menkveld,Gerhard A. Zielhuis,Régine P.M. Steegers-Theunissen +5 more
TL;DR: Total normal sperm count increases after combined zinc sulfate and folic acid treatment in both subfertile and fertile men, and this finding opens avenues of future fertility research and treatment and may affect public health.
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Effect of reactive oxygen species produced by spermatozoa and leukocytes on sperm functions in non-leukocytospermic patients
Ralf Henkel,Eva Kierspel,T. Stalf,Claas Mehnert,Roelof Menkveld,Hans-Rudolf Tinneberg,Wolf-Bernhard Schill,Thinus F. Kruger +7 more
TL;DR: The origin of ROS seems to have an influence on the site of the damage in sperm functions, and the threshold given by the World Health Organization (WHO) should be re-evaluated.