Subzonal sperm insemination and total or extreme asthenozoospermia: an effective technique for an uncommon cause of male infertility.

OBJECTIVE: To assess the value of subzonal insemination (SUZI) in cases of total or extreme asthenozoospermia. DESIGN: The results of IVF after SUZI were assessed in six cycles (four couples) with documented asthenozoospermia. SETTING: Institut de Médecine de la Reproduction, Marseille, France. PATIENTS: Four couples underwent six retrieval cycles. In all cases asthenozoospermia was total (100% of immotile spermatozoa) or extreme (5% nonprogressive motility). Oligozoospermia and teratozoospermia were ruled out in all cases. In two cases electron microscopy revealed the absence of the central singlet in the flagellum axonemal complex and in one case a major dysplasia of the fibrous sheath in the flagellum principal piece. RESULTS: The overall fertilization rate was 45%. The diploid embryo rate was 33%. Embryo quality was satisfactory. In five of six cycles, three embryos were transferred. Two triplet pregnancies were obtained corresponding to an implantation rate per transferred embryo of 40%. CONCLUSION: Total or extreme asthenozoospermia seems to be a good indication for SUZI.

Quantified ultrastructural study of spermatozoa in unexplained failure of in vitro fertilization.

Failure of in vitro fertilization or very low cleavage rates may occur even though oocyte and semen parameters seem satisfactory. Quantified ultrastructural study of spermatozoa was performed in such cases of failure (n = 6) or low cleavage rate (< 20%; n = 4). Through 1 to 11 retrievals, the number of inseminated oocytes ranged from 14 to 145. The results were compared to those of six fertile men. Quantification was achieved by cataloguing cell defects of the spermatozoon heads and mid-/principal pieces of the flagella. Using the data from each specimen, the percentages of total cellular abnormalities in the head/mid-/principal pieces were established. At the level of the head overall percentages for six groups of defects were determined. The overall percentage of combined head abnormalities, defined as the presence of at least three of these six defects on the same spermatozoon head, was established. Statistical differences among control and patient groups were analyzed by nonparametric Mann-Whitney U test. The percentages of anomalies of the midpiece and of the principal piece were not significantly different between patients and controls. Motility assessed by spermogram was considered "functionally uncompromised." In eight patients the percentage of cell alterations of the head (93-100 vs 77.3 +/- 6.4%) and the percentage of combined anomalies of the head (78.1-100 vs 60.8 +/- 8.5%) were significantly different between patients and controls. In two cases, the percentages established for all head parameters considered were not globally different from those observed in controls. Thus in 8 cases of 10, electron microscopy with quantified analysis supplied valuable evidence about the poor quality of these sperm samples judged as normal under light microscopy and may provide an explanation for their impaired fertilizability.(ABSTRACT TRUNCATED AT 250 WORDS)

Mesonephric origin of the gonadal primitive medulla in chick embryos.

The development of the gonadal primitive medulla in embryonic chick gonads was studied with the light microscope, using serial longitudinal sections from 72 h to 108 h of incubation. The sex of embryos was established from karyotypes. At 72 h, the germinal epithelium in the genital ridges was thickened. The nephrogenic cord was not differentiated into nephrons underneath, although the surrounding mesonephros displayed renal corpuscles and tubules. Clusters and trabeculae of mobilized mesonephric cells piled up under the germinal epithelium, forming the rudiment of the primitive medulla. From 78 h onwards, nephrotome-like structures existed in the mesenchyme underlying the germinal epithelium. Mesonephric cells became detached from their ventral walls and incorporated into the rudiment of the medulla. Finally, at 90 h, when the gonads were constituted, the primitive medulla was definitively formed without any contribution of the germinal epithelium. Adrenal cortical cells, also originating from the mesonephric blastema, showed tight relationships with the gonadal medullarian structures. Our observations support the concept of the mesonephric origin of the gonadal components having male potentialities in birds.

[Role of HY antigen in human and mammalian gonadal organogenesis (author's transl)]. / Rôle de l'antigène HY dans l'organogenèse des gonades chez l'homme et les mammifères.

H-Y (histocompatibility Y) antigen plays a role in gonadal organogenesis, which is poorly understood. Indeed, it is not immunologically well-defined. The use of cytotoxicity tests cannot lead to a right quantification of its expression. In vertebrates, it is a marker of the heterogametic sex. As it is also detected in invertebrates, H-Y antigen is therefore ubiquitous and has a high phylogenic conservation. Its role, as an organizer of mammal testes, was carried out by controversial experiments of dissociation-reorganization, in gonadal cells. In gonads. H-Y antigen can be studied under 3 diverse aspects : secretion, fixation and expression, Recently, Ohno proposed a very attractive pattern of testicular and ovarian organogenesis. In males, organization of seminiferous tubules is the result of the interaction between H-Y antigen and its specific gonadal receptor. In females, primordial follicle formation is induced by the interaction between an hypothetic ovary-organizing antigen (similar to H-Y antigen) and the same specific receptor as in testis. These different hypotheses are discussed. In addition, it is underlined how expression of H-Y antigen (anchorage site of H-Y antigen on plasma membrane associated with beta 2-m) can be distinguished from its fixation on gonadal specific receptors. In view of controversial data, the masculinisation of bovine free-martin gonads by H-Y antigen is discussed. In XX males and XY females, H-Y expression which is variable is correlated with its gonadal organizing role. Finally, at present time location of H-Y structural and control genes remains unsolved. In view of all hypotheses postulated, it is not clearly demonstrated how H-Y antigen can act on gonadal organogenesis. Nevertheless, priority of cell-cell recognition, via H-Y antigen, has to be emphasized.