Monosaccharide Transport Across Membranes of Human Spermatozoa

A method for determination of the monosaccharide uptake into human spermatozoa is described. Intracellular monosaccharide concentrations were calculated on the basis of determination of intracellular radioactivity after incubation of the cells with labelled monosaccharide and using a mathematical procedure to approximate the intracellular space of spermatozoa. The D-fructose uptake depends on the extracellular D-fructose concentration in a hyperbolic manner. Half maximal saturation is present at 4,1 mM. This corresponds closely with the lowest limit of D-fructose concentration in human fertile semen.     

GENETIC COUNSELING IN ASSISTED REPRODUCTION: A CASE OF CYSTIC FIBROSIS IDENTIFIED AFTER TWO SUCCESSFUL INTRACYTOPLASMIC SPERM-INJECTION PREGNANCIES

The aim of this study is to assess whether the type of penile curvature in normopotent men with Peyronie's disease affects the penil vascular doppler ultrasound parameters. Fifty-three normopotent patients within the stabilization phase of Peyronie's disease were evaluated retrospectively by means of color doppler ultrasonography. Bilateral cavernosal artery diameters before and after intracavernous papaverine injections, peak systolic and end diastolic velocities and the amount of leakage in the deep dorsal penile vein were compared in dorsal and ventral curvature groups of Peyronie's disease. 61% of the patients in dorsal and 59% in ventral Peyronie's curvature group have normal ultrasonographic penile vascular system. 35% and 3.3% in dorsal curvature group and 36.4% and 4.5% in ventral curvature group have venoocclusive dysfunction and mixed vascular pathologies, respectively, having no statistical correlation between them (p > 0.05). No arterial pathology was observed in any group. There was no correlation between the type of Peyronie's curvature and the penile doppler ultrasonographic findings in normopotent patients.     

Beta 1 -integrins of spermatozoa: a flow cytophotometric analysis

The expression of adhesion molecules on human ejaculated spermatozoa was investigated by means of flow cytophotometry using monoclonal antibodies against eight different adhesion molcules. Spermatozoa from infertility patients who exhibited normal semen parameters showed specific fluorescence after incubation with antibodies against very late antigens VLAα4, VLAα 5, VLAα 6, and corresponding matrix proteins laminin and fibronectin. Semen samples from men with teratozoospermia or oligoasthenoteratozoospermia were characterized by reduced expression of adhesion molecules. Normal and pathological semen samples differed mostly in the expression of VLAα5. After artificial induction of the acrosome reaction by a cold shock method and incubation with 2 mM Ca²⁺, a changed pattern of adhesion molecules on the sperm surface was found for VLAα6 as the most prominent molecule. After treatment of spermatozoa with 0.10% Triton X-100, the number of cells with adhesion molecules increased significantly. This result suggests that adhesion molecules are an integral part of sperm structure.     

Monosaccharide Transport across Membranes of Human Spermatozoa

Monosaccharidtransport über die menschliche Spermazellmembran II. Basiseigenschaften der D-Fruktose- und D-Glukoseaufnahme
Die D-Glukoseaufnahme durch die menschliche Spermazelle zeigt wie die Fruktose-aufnahme eine hyerbolische Kinetik. Die Affinitäten beider Monosaccharide zum Transportsystem sind ähnlich, aber die Transportkapazität ist für D-Glukose größer als für D-Fruktose. Beide Transportprozesse werden durch Monojodacetat gehemmt. Sie können als carriervermittelte aktive Transporte betrachtet werden. Der D-Glukosetransport ist durch Ouabain hemmbar und wird durch extrazelluläres Na beeinflußt. Diese Unterschiede können der Ausdruck dafür sein, daß für beide Monosaccharide unterschiedliche Transportsysteme existieren. Aber die Abhängigkeit der D-Glukose- und D-Fruktoseaufnahme vom extrazellulären D-Fruktose-D-Glukose-Konzentrationsverhältnis legt die Schlußfolgerung nahe, daß sich beide Systeme untereinander beeinflussen.     

The Equatorial Fibronectin Band (EFB) on Human Spermatozoa -a Diagnostic Help for Male Fertility?

Spermatozoa were prepared by swim up technique in the same way as for in vitro fertilization of human eggs and incubated with antihuman fibronectin antibodies in the immunofluorescence technique. Fibronectin mediates adhesive interactions between cells. 69 p.c. of spermatozoa with a normal shape and only 17 p.c. of them exhibiting a pathological shape showed a positive fibronectin-fluorescent band on the equatorial segment, called equatorial fibronectin band (EFB). The cryopreservation of semen did not influence the EFB. The significance of EFB for the sperm-oocyte-binding is discussed in connection with the sperm morphology and epididymal function.