Microfertilization techniques--the Swedish experience.

Intracytoplasmic sperm injection (ICSI) has been studied in this animal research programme since 1990. In 1993, the technique was first applied clinically and up to the present time (September 1994), a total of 456 couples have been studied in 538 cycles. The principal indication for the use of ICSI has been severe male sub-fertility as judged by a semen analysis. In addition, men with high titres of antisperm antibodies, blockage of the vas deferens and neurological disorders such as spinal cord lesions have been included in the programme. Men with genetic disorders such as cystic fibrosis and acrosome-deficient spermatozoa have also been treated successfully. The overall fertilization rate using ICSI was 59%, which is similar to the conventional in vitro fertilization (IVF) programme in Göteborg, however, the pregnancy rate per embryo transfer (29%) and the ongoing pregnancy rate per transfer (22%) were slightly lower. The total number of pregnancies was 144 with 111 of the pregnancies either ongoing or already delivered. To date, 36 healthy children have been born following 29 deliveries and no major malformations have been diagnosed. Being the first programme in Scandinavia to perform ICSI, this unit has experienced long waiting lists which indicates that severe male sub-fertility will be one of the major groups for treatment with assisted reproductive technologies in the future.

The use of silane-coated silica particles for density gradient centrifugation in in-vitro fertilization.

Silane-coated silica particles (PureSperm) were evaluated as an alternative to Percoll for gradient separation of spermatozoa, for use in assisted reproduction. Recovery of motile and morphologically normal spermatozoa after using a four-layer Percoll and a two- and four-layer PureSperm gradient respectively was recorded. In-vitro fertilization (IVF) results after using PureSperm for the sperm preparation were also evaluated. No difference in sperm recovery or sperm motility was found when comparing the use of Percoll and the four-layer gradient of PureSperm. When using a two-layer PureSperm gradient, motility was significantly decreased (P < 0.05) compared to Percoll. Normal sperm morphology increased from 8-17.2% after using Percoll and to 12.7% and 11.4% after using a four-layer and a two-layer PureSperm gradient respectively. All gradient preparations showed a significant decrease in the teratozoospermia index compared to the ejaculate (P < 0.01). No significant differences in IVF results regarding fertilization and pregnancy rates were found when PureSperm or the swim-up technique were used for the sperm preparation. PureSperm seems to be an acceptable alternative to Percoll but although the percentage of sperm recovery was higher after PureSperm we still recommend the swim-up technique to be the first choice, as a higher percentage of progressive motile spermatozoa is obtained without using other chemicals than IVF culture medium.

Acrosome index is not an absolute predictor of the outcome following conventional in vitro fertilization and intracytoplasmic sperm injection.

PURPOSE: To investigate if including evaluation of acrosome index (AI) in the semen analysis of teratozoospermic samples could help to predict for which patients intracytoplasmic sperm injection (ICSI) is necessary. METHODS: The fertilization rate, pregnancy rate, and percentage of good quality embryos were compared after performing conventional in vitro fertilization (IVF) and ICSI, respectively, using sibling oocytes. The role of AI was evaluated by dividing patients into two groups; Group A (AI < 7%) and Group B (AI > or = 7%). RESULTS: A significant difference in fertilization rate was observed between Group A and B after conventional IVF. In Group A, the fertilization rate, embryo transfer rate, and percentage of good quality embryos were higher after ICSI than after IVF. In Group B, the fertilization and pregnancy rates were numerically but not significantly higher after IVF compared to ICSI. CONCLUSION: Evaluation of acrosome index will not accurately predict fertilization, although this study shows that a sperm sample with less than 5% normal forms and an AI greater than 7% may achieve a mean fertilization rate > 70% after conventional IVF.

The relationship between sperm morphology and rates of fertilization, pregnancy and spontaneous abortion in an in-vitro fertilization/intracytoplasmic sperm injection programme.

The morphological normality of a spermatozoon is considered to be an important factor in relation to its ability to fertilize an oocyte. We examined the influence of morphology (strict criteria) on the rates of fertilization, pregnancy and spontaneous abortion obtained following conventional in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in our clinical programme. We found our fertilization cut-off values for conventional IVF to be slightly different from those of the Kruger group (10 and 5%, compared to 14 and 5%). We also found the pregnancy rate per transfer to be as good or better in the groups with < 5% normal forms: 36% of these men had a fertilization rate > 50% using conventional IVF, showing that fertilization capacity is not necessarily impaired even in this 'poor prognosis' group. With the exception of the ICSI group with 5-9% normal forms, the rate of spontaneous abortion in this study was similar to or lower than in our IVF/ICSI programme overall. When the 5-9% normal spermatozoa group was divided into those with teratozoospermia as the only factor and those with additional sperm factors, the increased abortion rate was found in the group with multiple sperm factors (67% spontaneous abortions).

Indications for intracytoplasmic sperm injection.

Intracytoplasmic sperm injection (ICSI) is the latest of several microfertilization techniques that have been utilized predominantly to overcome severe male subfertility, giving fertilization and term pregnancy rates similar to conventional in-vitro fertilization (IVF) (but for other indications). Even though available data on children born after ICSI are very encouraging, the procedure must still be considered as novel and the safety aspect to a great extent unexplored. In our opinion, therefore, ICSI should only be used for specific indications, and in this communication the non-existent, relative and absolute indications for performing ICSI are outlined and discussed. With an apparently normal sperm sample, ICSI should not be used in a first cycle even if only few oocytes are obtained. When there is reason to suspect poor fertilization, ICSI can be used in combination with conventional IVF in a split cycle. This includes cases of 'subnormal' sperm samples, high titres of antisperm antibodies, or following a single cycle of poor fertilization using conventional IVF. Absolute indications for ICSI include two previous fertilization failures with conventional IVF, use of epidiymal or testicular sperm samples, or when only acrosomeless or immotile spermatozoa are available. The fertilization of oocytes prior to preimplantation genetic diagnosis is another absolute indication. It is, however, important to keep in mind that for this novel technique, indications should not be rigid, but remain variable with respect to new findings.

Wear resistance of some prosthodontic materials in vivo.

The purpose of this study was to compare a gravimetric method and an impression technique in the evaluation of occlusal substance loss. The wear of gold, porcelain, and microfilled resin was studied in vivo. The gravimetric method showed lower substance loss for porcelain than for gold, whereas the microfilled resin had the highest substance loss. To obtain a higher accuracy for the measurement of occlusal substance loss of restorative materials with an impression technique, the test area has to be restricted, the antagonizing occlusal contacts carefully recorded before the test period, and the number of cuts increased. The observed structure of wear facets (SEM) corroborated with previous findings of the wear mechanism of these materials; that is, gold has mainly abrasive wear in contact with porcelain, whereas porcelain has a fatigue type and microfilled resin a tribochemical type of wear.

A self-migration method for preparation of sperm for in-vitro fertilization.

Human sperm samples (n = 211) were prepared for in-vitro fertilization (IVF) and embryo transfer by a self-migration procedure in Earle's medium containing highly purified hyaluronic acid (Hya) (MW 3,000,000) included to increase the viscosity of the medium. The method resulted in the recovery of a significantly higher percentage of motile spermatozoa compared with the traditional centrifugation method, 87.5 +/- 0.9% versus 76.1 +/- 1.3% (P less than 0.001). When comparing media with and without Hya in the self-migration method for preparation of normal sperm samples, the media containing Hya resulted in the recovery of a significantly higher percentage of motile spermatozoa, 89.0 +/- 0.8% versus 73.8 +/- 2.0% (P less than 0.001). In a group of 80 consecutive couples entering our IVF programme, sperm samples from 44 of the men were allocated at random for the self migration method in medium containing Hya and sperm samples from 36 men for preparation by centrifugation and swim-up. Significantly more pregnancies were achieved in the group prepared in medium containing Hya. It is concluded that self-migration of sperm in a medium containing Hya is simple and rapid, and results in a high recovery of motile spermatozoa which can be used for in-vitro insemination of human oocytes with favourable results.

Sperm retrieval, fertilization, and pregnancy outcome in repeated testicular sperm aspiration.

PURPOSE: To report the outcome of sperm retrieval and results after ICSI in up to six repeated testicular sperm aspiration procedures. METHODS: Twenty-two men with obstructive and thirty-four men with nonobstructive azoospermia underwent 50 and 91 needle aspirations, respectively. Sufficiency of spermatozoa for ICSI and cryopreservation, fertilization rate, and pregnancy outcome was analyzed retrospectively. RESULTS: No major differences were found in sperm recovery or pregnancy outcome in the repeated cycles. Testicular aspirate containing motile spermatozoa with maintained fertilizing capacity was obtained in up to six repeated procedures in the nonobstructive group. No postoperative complications were reported for any of the participants. CONCLUSIONS: Testicular sperm aspiration is a simple and effective method of sperm retrieval, which can be performed from the same testis up to several times with good recovery of motile spermatozoa for ICSI and maintaining high fertilization and pregnancy rates, in men with both obstructive and nonobstructive azoospermia.

Diagnostic epididymal and testicular sperm recovery and genetic aspects in azoospermic men.

Various procedures for sperm recovery in azoospermic men have been described, from open testicular biopsy to simple needle aspiration from the epididymis and the testis. Fifty-one obstructive and 86 non-obstructive azoospermic men were treated to compare the recovery of spermatozoa obtained by percutaneous aspiration from the epididymis (PESA) and aspiration/extraction from the testis (TESA, TESE) with histopathology. If TESA failed, the work up proceeded with TESE. All patients were karyotyped. Spermatozoa were recovered by PESA or TESA in all obstructive men (51/51 patients). In 22 out of 86 patients with non-obstructive azoospermia, testicular spermatozoa could be successfully recovered by TESA. In five additional patients TESE was successful in recovering spermatozoa where TESA had failed. In 43 patients, neither TESA nor TESE was successful. Sixteen patients chose not to proceed with TESE. Seven out of 86 patients had an abnormal karyotype in the non-obstructive group (8%), none in the obstructive group. In the non-obstructive patient group testicular histopathology showed hypospermatogenesis, incomplete maturation arrest and germ cell aplasia with focal spermatogenesis in cases where spermatozoa were recovered and complete germ cell aplasia, complete maturation arrest and fibrosis in cases where no spermatozoa were found. Spermatozoa were recovered by PESA or TESA from all patients with obstructive azoospermia and from approximately 40% of patients with non-obstructive azoospermia by TESA or TESE. Retrieval of viable spermatozoa in the infertility work-up was highly predictable for sperm recovery in subsequent ICSI cycles. TESA performed under local anaesthesia seems almost as effective as more invasive procedures in recovering testicular spermatozoa, both in obstructive and non-obstructive azoospermic men.