Distribution of spermatogenesis in the testicles of azoospermic men: the presence or absence of spermatids in the testes of men with germinal failure [published erratum appears in Hum Reprod 1998 Mar;13(3):780]

The aim of the study was to determine whether a prior diagnostic testicle biopsy can predict success or failure of testicular sperm extraction (TESE) with intracytoplasmic sperm injection (ICSI) in patients with non-obstructive azoospermia caused by testicular failure, and what is the minimum threshold of sperm production in the testis which must be surpassed for spermatozoa to reach the ejaculate. Forty- five patients with non-obstructive azoospermia caused by testicular failure underwent diagnostic testicle biopsy prior to a planned future TESE-ICSI procedure. The diagnostic testicle biopsy was analysed quantitatively, and correlated with the quantitative findings of spermatogenesis in patients with normal spermatogenesis, as well as with the results of subsequent attempts at TESE-ICSI. Men with non- obstructive azoospermia caused by germinal failure had a mean of 0-6 mature spermatids/seminiferous tubule seen on a diagnostic testicle biopsy, compared to 17-35 mature spermatids/tubule in men with normal spermatogenesis and obstructive azoospermia. These findings were the same for all types of testicular failure whether Sertoli cell only, maturation arrest, cryptorchidism, or post-chemotherapy azoospermia. Twenty-two of 26 men with mature spermatids found in the prior testis biopsy had successful retrieval of spermatozoa for ICSI, 12 of their partners became pregnant, and are either ongoing or delivered. The study suggests that 4-6 mature spermatids/tubule must be present in the testis biopsy for any spermatozoa to reach the ejaculate. More than half of azoospermic patients with germinal failure have minute foci of spermatogenesis which are insufficient to produce spermatozoa in the ejaculate. Prior diagnostic testicle biopsy analysed quantitatively (for the presence of mature spermatids) can predict subsequent success or failure with TESE-ICSI. Incomplete testicular failure may involve a sparse multi-focal distribution of spermatogenesis throughout the entire testicle, rather than a regional distribution. Therefore, it is possible that massive testicular sampling from many different regions of the testes may not be necessary for successful TESE-ICSI.      

Adhesion inhibitory activity of β-lactoglobulin isolated from infant formulae

β-Lactoglobulin was isolated from infant formulae that were ultra high temperature (UHT) -treated, sterilized or spray-dried. The effect of the isolated β-lactoglobulin on SfaII-fimbriae-mediated adhesion of Escherichia coli to human ileostomy glycoproteins was studied in vitro. β-Lactoglobulin isolated from sterilized formulae was found to perform significantly less well than preparations from spray-dried formulae (p = 0:05). Great heterogeneity was observed in the adhesion inhibitory capacity of β-lactoglobulin isolated from UHT-treated formulae. Therefore, no significant difference was observed between UHT-treated and sterilized formulae or spray-dried formulae (p < 0:10). It can be hypothesized that β-lactoglobulin from spray-dried and some UHT-treated infant formulae may affect the colonization of mucous membranes by E. coli strains causing neonatal septicaemia and meningitis.     

Development of a transformation system for Crinipellis perniciosa,the causal agent of witches' broom in cocoa plants

Protoplasts of the pathogenic plant fungus, Crinipellis perniciosa, were transformed to hygromycin B resistance using the pAN7-1 plasmid, which contains the Escherichia coli hph gene under the control of Aspergillus nidulans regulatory sequences. The pAN7-1 plasmid was introduced by PEG/CaCl(2) treatment. Transformation frequencies of 1.6-2.5 transformants/microg of DNA were achieved. About 54% of the transformants were abortive and 40 analyzed transformants were mitotically stable and showed different hygromycin B resistance levels. The presence of the hph gene was checked by PCR in five transformants and the integration of multiple plasmid copies into different genome sites was observed by Southern analysis. This is the first report of a C. perniciosa transformation system and represents an important step for further research into genetic manipulation of this fungal plant pathogen.     

Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy

The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal- specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.      

Effect of timing of oocyte denudation and micro-injection on survival, fertilization and embryo quality after intracytoplasmic sperm injection

In human in-vitro fertilization (IVF), the oocytes are surrounded by cumulus and corona cells at the time of insemination so that their maturity cannot easily be evaluated. The best IVF results are obtained if the oocytes are inseminated 2-6 h after retrieval. In the intracytoplasmic sperm injection (ICSI) procedure, the oocytes are denuded by enzymatic and mechanical treatment in order to be able to perform the injection. As a consequence, the nuclear maturity of the oocytes can be evaluated and only those that have extruded the first polar body are injected. However, metaphase-II oocytes that have not yet reached cytoplasmic maturity cannot be recognized. The purpose of this study was to investigate the effect of different timing of cumulus- corona cell removal and injection on the outcome of ICSI. For this we allowed the oocytes to complete in-vitro cytoplasmic maturation in two different culture conditions: (i) surrounded by their cumulus and corona cells or (ii) totally denuded. We performed three different studies on sibling oocytes obtained after a standardized buserelin/human menopausal gonadotrophin (HMG) protocol. We investigated the effect of early (1-2 h after retrieval) and late (5-6 h after retrieval) oocyte denudation and injection on the survival and fertilization of the injected oocytes and on embryo cleavage after fertilization. We found no statistically significant differences between early and late injection, indicating that after a standardized buserelin/HMG protocol the metaphase-II oocytes do not need time for further cytoplasmic maturation. Furthermore, a different timing of cumulus-corona cell removal has no effect on the outcome of ICSI, suggesting that the surrounding cells are not necessary for survival, fertilization and cleavage after ICSI.      

Relationship between serum follicle stimulating hormone in the male and standard sperm parameters, and the results of intracytoplasmic sperm injection

Serum follicle stimulating hormone (FSH) is routinely measured when evaluating the infertile male for intracytoplasmic sperm injection (ICSI). However, among the sperm parameters, only its relationship with sperm concentration is well documented. Few investigations concern the relationship between FSH and sperm motility and morphology, and the results of ICSI. A retrospective study of 316 couples who underwent ICSI was carried out to determine the relationships between serum FSH concentrations in the male and (i) standard sperm parameters_(concentration, motility and morphology) and (ii) fertilization, cleavage, pregnancy and implantation rates after ICSI. There was an inverse correlation with sperm concentration and total motility but no relationship was found with progressive motility and sperm morphology. Neither was any relationship found between serum FSH and fertilization, cleavage, pregnancy and implantation rates, and the results of ICSI. These findings suggest the need to review the routine measurement of serum FSH in the infertile male when ICSI is the planned treatment procedure.