Rob F.A. Weber

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Human germ cell tumors (GCTs) may have variable histology and clinical behavior, depending on factors such as sex of the patient, age at clinical diagnosis, and anatomical site of the tumor. Some types of GCT, i.e., the seminomas/germinomas/dysgerminomas and embryonal carcinomas (the stem cell component of nonseminomas), have pluripotent potential, which is(More)
Little is known on environmental risk factors for cryptorchidism and hypospadias, which are among the most frequent congenital abnormalities. The aim of our study was to identify risk factors for cryptorchidism and hypospadias, with a focus on potential endocrine disruptors in parental diet and occupation. In a case-control study nested within a cohort of(More)
Testicular germ-cell tumors (TGCTs) of adolescents and adults originate from intratubular germ cell neoplasia (ITGCN), which is composed of the malignant counterparts of embryonal germ cells. ITGCN cells are characterized, among others, by the presence of stem cell factor receptor c-KIT. Once established, ITGCN will always progress to invasiveness.(More)
Androgens play a crucial role in the development of male reproductive organs such as the epididymis, vas deferens, seminal vesicle, prostate and the penis. Furthermore, androgens are needed for puberty, male fertility and male sexual function. High levels of intratesticular testosterone, secreted by the leydig cells, are necessary for spermatogenesis.(More)
AIM To evaluate whether inhibin-B can predict the outcome of a microsurgical epidymal sperm aspiration (MESA) procedure in patients with suspected primary obstructive azoospermia (OA) and if inhibin-B can replace testicular biopsy in the diagnostic work-up of these patients. METHODS Inhibin-B levels and testicular biopsy scores were related to the outcome(More)
BACKGROUND The aim of this study was to evaluate the long-term gonadal sequelae after treatment for childhood Hodgkin's lymphoma with combination chemotherapy, using up to date fertility parameters and andrological evaluation, including for the first time inhibin B. METHODS There were 56 male patients treated from 1974-1998 for childhood Hodgkin's(More)
It is inconclusive whether the feedback mechanisms of the hypothalamus-pituitary-testis (HTP) axis are already established in the first 6 months of life, partly due to the dramatic changes in HPT-axis hormone levels over this period. Moreover, it is unclear whether these hormone levels are aberrant in boys with cryptorchidism or hypospadias, and therefore(More)
The aim of this study was to investigate the relation between free testosterone (FT) level and basic cognitive functions in older men. Three cognitive computer tasks were aimed to measure visual-processing speed, ability to suppress inappropriate responses, and visuospatial cognition, respectively. The tasks employed were a visual backward masking task, the(More)
An assumption in case-control studies is that forces of selection are the same for cases and controls. This may not be true for studies of male infertility among infertility clients. Earlier reproductive outcomes may introduce modification of risk behavior or differential referral. Selection bias might also occur when infertile males are compared with(More)
There is a definite need for an effective and reversible form of male contraception, both for maintaining a stable population in industrial countries and for diminishing population growth in developing countries. It has been agreed upon that contraception is an essential component of reproductive health for men and women (the Weimar Manifesto on Male(More)