[Future of the treatment of male infertility]

The aim of this paper is to introduce inherent difficulties leading to relative delay in the field of male infecundity treatment. Four theoretical possibilities are exposed: infertility prevention improvement, qualitative or quantitative improvement of spermatogenesis, spermatozoa fecundity ability improvement and micro-fertilization procedures. These methods are exposed in their technical aspects and in their results. Critical analysis is conducted about some impressive reported series. Basic knowledge improvement seems to be necessary to explore new therapeutic ways.

Utility of zona pellucida drilling in cases of severe semen alterations in man

OBJECTIVE

To evaluate the utility of zona drilling for human severe sperm alterations in in vitro fertilization (IVF).

DESIGN

A prospective randomized study was conducted according to random assignment of collected oocytes to a control or zona drilling procedure.

SETTING

Reproductive Biology Laboratory, University Hospital of Nantes, France.

PATIENTS

Twenty infertile couples with severe semen defects and previous IVF failure.

INTERVENTIONS

Ultrasound-guided transvaginal follicular aspiration.

RESULTS

Fertilization rates were compared to assess the advantages of zona drilling: 93% (80/86) drilled oocytes survived and 18.75% (15) were fertilized, whereas only 3% (3/100) control oocytes were fertilized. The polyspermy rate for fertilized drilled oocytes was high (10/15; 66.6%). The normal fertilization rate after zona drilling remained very low (5/86; 5.8%) and was not statistically different from that of control oocytes (3/100; 3%). One implantation occurred after replacement of five drilled embryos in three patients but resulted in early miscarriage. Replacement of the single control embryo led to a progressive pregnancy and normal male birth.

CONCLUSIONS

This study indicates that zona drilling does not improve IVF results in cases of severe semen alterations.

Effects of some growth regulators on in vitro tuberization in Dioscorea alata L. 'Brazo fuerte' and D. abyssinica Hoch

Nodal cuttings of Dioscorea alata L. 'Brazo fuerte' and D. abyssinica Hoch. were cultured in vitro to assess the influence of NAA on the production of microtubers. In D. alata, high concentrations of NAA (27 and 54 μM) favored the production of large microtubers, whereas the highest number of microtubers was obtained with 2.7 μM. D. abyssinica was found to be more sensitive to NAA since concentrations higher than 0.27 μM promoted the growth of callus on the root system. In this species, the production of the largest microtubers was obtained at 2.7 μM whereas the number of microtubers was not affected by any concentration tested. In D. alata, the effects of ABA and BAP were also evaluated. The weight of the microtubers increased with increasing concentrations of ABA. This effect, however, was observed only on expiants cultured under 8 h photoperiod, but not on those cultured under 16 h. Finally the presence of BAP at concentrations as low as 0.22 μM adversely affected the survival of the explants.

Indolelactate dehydrogenase from Clostridium sporogenes

Indolelactate dehydrogenase has been purified 13-fold from cell-free extracts of Clostridium sporogenes. The enzyme is inactive with lactate, but active with indolelactate, phenyllactate, and p-hydroxyphenyllactate, and utilizes nicotinamide adenine dinucleotide (NAD) but not nicotinamide adenine dinucleotide phosphate NADP (1), as coenzyme. The reaction is reversible; the equilibrium constant is 6.3 × 10−6 M at pH 7.0, expressed as [indolepyruvate] [NADH] [H+]/[indolelactate] [NAD].The enzyme preparation exhibits regular Michaelis–Menten kinetics with respect to indolelactate, NAD, and NADP, but not with respect to indolepyruvate.