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Dive into the research topics where Jacob H. Aafjes is active.

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Featured researches published by Jacob H. Aafjes.


Fertility and Sterility | 1985

Fertility of men with and without a varicocele.

Jacob H. Aafjes; Jan C.M. van der Vijver

The fertility of 742 men visiting our male infertility clinic was studied. A comparison was made between patients operated on for varicocele and patients treated in other ways. Of the men with a varicocele, 37.8% impregnated their partners; of the men without a varicocele, 21.5%. By subdivision of the total group of patients into those with sperm counts above and those with sperm counts below 20 X 10(6)/ml, it appeared that only men with low sperm counts operated on for varicocele showed a significantly higher fertility, as compared with patients not having a varicocele. It is suggested that patients not having oligozoospermia perhaps have spermatozoal defects other than too low a number as the principal cause of their infertility which do not significantly improve after varicocele operation.


Life Sciences | 1982

Proteolytic enzymes stimulate human spermatozoal motility and in vitro hamster egg penetration

Jacques Cohen; Jacob H. Aafjes

Addition of chymotrypsin or trypsin decreased the viscosity of highly viscous semen of subfertile patients. Besides that spermatozoal motility (in 50-80% of the case) and in vitro fertilizing ability was measured with zona-free hamster ova (in 35% of the cases) were increased of both normal and highly viscous semen.


Andrologia | 2009

Double-blind cross over treatment with mesterolone and placebo of subfertile oligozoospermic men value of testicular biopsy.

Jacob H. Aafjes; Jan C.M. van der Vijver; F.W. Brugman; P. E. Schenck

Doppelblind‐cross over‐Studie einer Therapie mit Mesterolon von Männern mit Oligozoospermie Die Bedeutung der Hodenbiopsie


Andrologia | 2009

Fumarase Activity in Human Ejaculate Relationship to Sperm‐Motility or ‐Penetration of Zona‐Free Hamster Eggs

Jacob H. Aafjes; J. Cohen; J.T.M. Vreeburg; H.J. Wolffensperger‐Van Oort

Fumarase activity, sperm count, sperm motility and in vitro fertilizing ability of spermatozoa were determined in semen samples of 69 men attending an infertility clinic. There existed a significant correlation between sperm count and fumarase activity (r = 0.52). No significant relationship was observed between sperm motility or hamster egg fertilizing ability of the spermatozoa and fumarase activity. From these results it is concluded that fumarase activity in human ejaculates can probably not be used to define the fertilizing ability of spermatozoa.


Fertility and Sterility | 1984

Comparison of photographic (multiple-exposure photography) and conventional evaluation of ejaculates for fertility prognosis

Jacob H. Aafjes; Robert Euser; P. E. Schenck

Semen obtained from 191 men visiting our infertility clinic was studied by MEP and conventional methods. With MEP, sperm count, percentage of motility, sperm velocity, straight line approach, and speed constancy were determined. Two years afterward 49 of the men appeared to have fertilized their partners. Between the fertile and infertile men, no differences in motility values determined by MEP could be detected. The only differences observed existed in sperm count and duration of infertility.


Fertility and Sterility | 1978

The duration of infertility: an important datum for the fertility prognosis of men with semen abnormalities.

Jacob H. Aafjes; Jan C.M. van der Vijver; P. E. Schenck


BMJ | 1978

Value of a testicular biopsy rating for prognosis in oligozoospermia.

Jacob H. Aafjes; J C van der Vijver; P. E. Schenck


European Journal of Endocrinology | 1977

Serum gonadotrophins, testosterone and spermatogenesis in subfertile men.

Jacob H. Aafjes; J. C. M. van der Vijver; R. Docter; P. E. Schenck


Fertility and Sterility | 1974

A Relationship Between Testicular Biopsy Score Count and Fertility of Men Treated for Oligospermia

Jacob H. Aafjes; Jan C.M. van der Vijver


European Journal of Endocrinology | 1978

SERUM GONADOTROPHINS IN RATS AFTER CASTRATION OR HEAT TREATMENT OF THE TESTES

Jacob H. Aafjes; J. T. M. Vreeburg; P. E. Schenck

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P. E. Schenck

Erasmus University Rotterdam

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F.W. Brugman

Erasmus University Rotterdam

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J. Cohen

Erasmus University Rotterdam

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J.T.M. Vreeburg

Erasmus University Rotterdam

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Jacques Cohen

Erasmus University Rotterdam

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Robert Euser

Erasmus University Rotterdam

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Paul G. McDonough

Georgia Regents University

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