In vitro tests for essential sperm functions using the phyto-oestrogen genistein as a test substance.

Sperm motility, binding of spermatozoa to the zona pellucida and induction of the acrosome reaction are prerequisites for successful oocyte fertilization. Examination of the physiological and nonphysiological effects of particular compounds on sperm functions requires high-quality in vitro test systems. In this short methodological overview, a reliable combined in vitro test system with bovine gametes is described. The purpose of the study was to evaluate whether aliquots of pooled post-thaw spermatozoa are suitable for examination of environmental substances that affect essential sperm functions. The combined test system includes a number of known methods for the assessment of sperm vitality and motion parameters, acrosomal status, inducibility of acrosome reaction and sperm zona pellucida binding. First observations indicate that genistein inhibits the induction of acrosomal exocytosis and binding of spermatozoa to the zona pellucida. Motility parameters and the viability of bovine spermatozoa were not affected by this substance. It is concluded that genistein, a phyto-oestrogen which is abundant in several plants, can be used as a test substance for the evaluation of effects upon essential bovine sperm functions in vitro.

[Edeka does all--machine speech recognition in social medicine expert testimony]. / Edeka will alle--maschinelle Spracherkennung in der sozialmedizinischen Begutachtung.

UNLABELLED: Automatic speech recognition systems are already being used in spheres employing a restricted vocabulary. OBJECTIVE: Our aim was to investigate whether low-cost speech recognition software for PC is capable of being usefully employed in the sphere of sociomedicine. MATERIALS AND METHODS: To this end 34 representative pages of text (a total of 11,000 words) taken from expertises on cases of suspected medical malpractice (many different subspecialties) were dictated using IBM's "Voice Type Simply Speaking" software. Having completed a page, the resulting error rate was recorded, and the text was corrected before we proceeded with the dictation. Finally, 3 pages of text were re-dictated and the resulting error rate determined. RESULTS: The error rate in the previously unknown text ranged between 10 and 23 per cent (mean 15.9%) without any significant reduction during the training phase, while that in the re-dictated text was drastically reduced to less than 3 per cent. It became evident that once a word was corrected the system hardly ever repeated that particular mistake. CONCLUSION: The system's poor performance on unknown text and the missing reduction in the error rate during the training phase are obviously not due to any incompetence of the system but to the huge amount of technical jargon in the scope of medical writing. To attain an acceptable performance we suggest to either extend the training phase, or, preferably, to confine the application to a single medical subspecialty. Its overwhelming learning ability makes the system a serious candidate typist in the sphere of sociomedicine.

Effect of angiotensin converting enzyme (ACE) and angiotensins on human sperm functions.

The presence of components of the renin angiotensin system (RAS) and specific receptors of angiotensin II in the female and male reproductive tract supports the hypothesis that reproductive functions may be controlled by RAS. Therefore, the present study investigated the influence of ACE and angiotensins on sperm functions and the sperm-egg interaction. The experiments did not indicate direct effects of ACE on the capacitation process or acrosome reaction. Release of ACE from human spermatozoa during capacitation was not related to their ability to undergo acrosome reaction after stimulation with ionophore. Therefore, ACE release does not seem to be a useful clinical marker for human sperm capacitation. However, decreased binding of human spermatozoa to the oolemma of zonafree hamster oocytes after inhibition of ACE by captopril indicates that kininase II is involved in sperm-egg interactions. In contrast to other studies, incubation with captopril had no influence on sperm binding to the zona pellucida. Because effects of ACE on sperm-egg interactions but not on capacitation or acrosome reaction were observed, several experiments were performed to study the influence of substrates and products on the acrosome reaction. Angiotensin II induced the acrosome reaction dose-dependently, whereas angiotensin I had no effect on the acrosome reaction. The effect of angiotensin II on acrosome reaction seems to be calcium-dependent and mediated by protein kinases. Since a specific type 2 angiotensin II receptor inhibits the acrosome reaction induced by angiotensin II, this subtype of receptors may be present at the surface of sperm heads. Another clue for the presence of type 2 receptors on human spermatozoa is the finding that pertussis toxin did not inhibit the angiotensin II induced acrosome reaction. In contrast to type 1 angiotensin II receptors, type 2 receptors are known to be G-protein independent.

Immunological identification of zona pellucida 2 (ZP2) protein in human oocytes.

The ZP2 protein is a zona pellucida glycoprotein that plays a major role in fertilization. It mediates secondary binding of spermatozoa and is one of the proteins that are involved in zona 'hardening'. ZP2 proteins were identified in various mammalian zonae pellucidae. Their primary structures are highly conserved as revealed by cDNA cloning. Antisera were used against synthetic peptides generated either against a ZP2 amino acid that is homologous in human and mouse ZP2 amino acid sequences (AS ZP2-20) or antibodies against a synthetic human ZP2 peptide (AS ZP2-26). Immunoblots showed that antiserum AS ZP2-20 and AS ZP2-26 strongly recognized human ZP2 protein with an apparent molecular mass of about 72 kDa; both antisera reacted with a minor immunoreactive polypeptide at 96 kDa. In human ovary sections, both antisera revealed immunoreactivity to human zonae pellucidae. Immuno-electron microscopy demonstrated an equal distribution of ZP2 throughout the human zona pellucida. Considerable amounts of immunoreactive material were observed in the ooplasm; some ramification-like extensions of zona pellucida antigen were found close to cells surrounding the oocyte. Our results indicate that antisera against synthetic ZP2 peptides can be used as specific markers for the identification of ZP2 protein in human oocytes.

Evaluation of ZP2 domains of functional importance with antisera against synthetic ZP2 peptides.

The mouse zona pellucida protein ZP2 plays an important role in the process of fertilization by mediating secondary sperm binding to mammalian oocytes. ZP2 primary structures are highly conserved as revealed by cDNA cloning. The aim of the study was to identify ZP2 domains of functional relevance. Antisera were raised against synthetic peptides that are either conserved in the structure of ZP2 from different mammalian species (AS ZP2-20) or present in the human ZP2 but not in the mouse ZP2 amino acid sequence (AS ZP2-26). Antibody binding to zona pellucida proteins was assessed by assaying the antisera with human hemizonae. Using human zonae pellucidae, we demonstrated that anti-ZP2 common antibodies and anti-ZP2 human peptide antibodies react with human zona pellucida antigens. For the first time, ZP2 domains of functional relevance for human sperm-oocyte interaction could be identified applying the competitive hemizona assay. Antiserum AS ZP2-20 significantly inhibited binding of spermatozoa to test hemizonae, whereas treatment of hemizonae with AS ZP2-26 did not influence sperm-oocyte interaction. These results show that antibodies against synthetic ZP2 peptides react with ZP2 protein and that AS ZP2-20 identifies a linear ZP2 epitope that is of possible functional importance for sperm-oocyte interaction.

A new combined in-vitro test model for the identification of substances affecting essential sperm functions.

Binding of mammalian spermatozoa to the zona pellucida and the induction of the acrosome reaction are prerequisites for successful oocyte fertilization. It has been postulated that xenobiotics that are released in the environment as well as exposure to pharmaceutical medications may be associated with reproductive problems in men and wildlife. Examining physiological and non-physiological effects of particular compounds on sperm functions requires high quality in-vitro test systems. We established a reliable combined in-vitro test system with bovine gametes and evaluated if aliquots of pooled post-thaw spermatozoa are suitable for examining essential sperm functions. Using cryopreserved semen, the PSA-FITC/Hoechst 33258 staining procedure was applicable to evaluate the acrosomal status and cell viability. In the bovine hemizona assay, hemizona indices revealed no differences between cryopreserved and fresh semen. Treatment of post-thaw bovine spermatozoa with progesterone (1 microM or bovine follicular fluid (20%) induced the acrosome reaction from 12% (untreated spermatozoa) to 25% (P < 0.001) and to 22% [corrected] (P < 0.01), respectively. Incubation of both compounds (1 microM progesterone and 20% follicular fluid) raised the percentage of acrosome-reacted spermatozoa to 30% (P < 0001). Our results demonstrate that cryopreserved semen can be integrated into an in-vitro screening model for reproductive toxicology testing. Pooled, cryopreserved bovine spermatozoa will thus permit reproducible experiments for clinical and basic science purposes and may also be applicable for the human system.

The zona pellucida "receptors".

Binding of mammalian sperm to the zona pellucida and the induction of the acrosome reaction are prerequisites for successful oocyte fertilization. In the mouse model, the zona pellucida consists of three sulfated glycoproteins, ZP1, ZP2, and ZP3. Zona pellucida proteins are secreted to form a filamentous zona matrix in which ZP2 and ZP3 complex into co-polymers cross-linked by ZP1. ZP3 is the ligand for primary sperm binding and important for the induction of the acrosome reaction. The zona pellucida glycoprotein ZP2 is also crucially involved in the process of fertilization. Previous reports suggest that ZP2 mediates secondary binding of spermatozoa and that cleavage of ZP2 by proteases released through cortical granule reaction causes zona "hardening" and thus prevents polyspermy. Human and mouse ZP2 proteins differ in the primary structure as derived from cDNA clones. We designed an immunological approach to search for ZP2 domains with functional relevance. Antisera were generated against synthetic peptides derived (a) from ZP2 amino acid sequences that are homologous in human and mouse ZP2 amino acid sequences (AS ZP2-20) or (b) from human ZP2 amino acid sequences that differ from the mouse ZP2 sequence (AS ZP2-26). Immunochemical studies with microbisected bovine zonae pellucidae demonstrated that both antisera, AS ZP2-20 and AS ZP2-26, specifically detected ZP2 protein. Using the competition-hemizona-assay, sperm binding to antibody treated bovine hemizonae pellucidae were compared with control hemizonae (given as hemizona index). Antiserum AS ZP2-20 significantly inhibited binding of spermatozoa to test hemizonae (p < 0.0001), whereas treatment of hemizonae with AS ZP2-26 did not influence sperm-egg interaction. Our results show that antibodies against ZP2 peptides react with bovine zonae pellucidae and can be used as markers for ZP2. Furthermore, AS ZP2-20 identifies a ZP2 epitope that is possibly of functional relevance for sperm-egg interaction.

Co-existence of gametic and agametic seminiferous tubules in a chimeric mouse. A light- and electron-microscopic study.

Six chimeras, including 4 phenotypic males and 2 females, were produced by aggregation of F1 (C57BL x BALB/c) and Swiss white embryos. All were fertile, except 1 male, whose deviation in testicular structure prompted this light- and electron-microscopic study. This chimera had a well-developed sperm-conducting system, sperm in the epididymis and active accessory sex glands. The testes displayed typical parenchymal and stromal components with the important exception of co-existence of gametic and agametic seminiferous tubules. These tubules were organized in territories of quasi-lobular configurations which appeared to open separately into rete testis. The former corresponded to normally developed and active seminiferous tubules, while the latter were solid testicular cords devoid of any germ cells and embedded in solid masses of interstitial (Leydig) cells. Special mitochondrial transformations were identified in sustentacular (Sertoli) cells of both types of tubules, in maturing spermatids and sperm. These and other submicroscopic sperm defects might be the cause of infertility.

Effect of separating bull semen into X and Y chromosome-bearing fractions on the sex ratio of resulting embryos.

Seventy-six, day 12 to day 15 bovine embryos, collected from 14 donors which had been inseminated with either X or Y chromosome-bearing spermatozoa fractions of semen separated by a thermal convection counterstreaming sedimentation and forced convection galvanization process, were processed for sexing by chromosomal analysis. Fifty-seven embryos were sexed; 20 from Y chromosome-bearing and 37 from X chromosome-bearing fractions of semen. Statistical analysis of the sexing data indicated that there was no significant difference in the male: female ratio for donors receiving male fractions compared to those receiving female fractions. The Y chromosome-bearing fractions produced a male: female ratio that was indistinguishable from the expected 1:1 ratio. However, the X chromosome-bearing fractions of semen produced a highly significant deviation from the expected 1:1 ratio towards the male.

[Severe fetal hemorrhage from a vas aberrans after amniotomy within the scope of labor induction]. / Starke kindliche Blutung aus einem Vas aberrans nach Amniotomie im Rahmen einer Geburtseinleitung.

Case report about a complication of amniotomy to be seen very seldom. An injury of a vas aberrans within the induction of labour was the cause of a fetal bleeding which indicated a cesarean section because of a pathologic cardiotocogramme. The further development of the newborn was undisturbed after primary resuscitation and fractionated blood transfusions. Incidence and meaning of pathologic insertions of the umbilical cord are represented.