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P Vanderzwalmen

Publications and source records attributed to P Vanderzwalmen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Intracytoplasmic injection of spermatids retrieved from testicular tissue: influence of testicular pathology, type of selected spermatids and oocyte activation.

Spermatid microinjection into oocytes has proven to be a successful assisted reproduction procedure in the animal model and in the human species, since in the latter a few full-term pregnancies were actually obtained. Patients entering our spermatid injection study included those with a total absence of spermatozoa in the testicular tissue notwithstanding previous positive biopsies (n = 29): an obstructive problem (n = 3), secretory azoospermia (n = 26), and those with total arrest at the spermatogenesis level in previous explorative biopsies (n = 15). In the latter group, absence of spermatids was recorded in four cases. Mature, elongated, elongating and round spermatids (ROS) were injected in respectively 3, 2, 3, and 32 attempts. A total of 260 metaphase II oocytes were injected with ROS, 36 oocytes with spermatids at other stages of maturity. The rates of oocytes showing two pronuclei (2PN) and two polar bodies reached 22% and 64% respectively after injection of round or elongated-mature spermatids. The fertilization rate after ROS injection was influenced by the percentage of spermatozoa observed in a previous biopsy. Patients with a positive preliminary biopsy had significantly more 2PN (33%) when compared to those with a severe spermatogenic dysfunction and in whom no spermatozoa were found (only 11%) (P < 0.05). Incubation of oocytes in calcium ionophore after ROS injection had a positive effect on the rate of 2PN formation (36 versus 16%). Ninety per cent of all the normally fertilized oocytes cleaved. The percentage of grade A and B embryos depended on the type of injected cells: 12% after ROS and 30% with the other types of haploid cells. A total of 39 transfers resulted in five pregnancies: three full term with healthy babies delivered (one after ROS injection, and two after injection of an elongating and a mature spermatid), one 4 months ongoing (after elongating spermatid injection) and one miscarriage at 4 weeks (after elongated cell injection). Compared to our conventional intracytoplasmic sperm injection-testicular sperm extraction (ICSI-TESE) programme, the implantation rate after ROS injection was very low (5.5 versus 10.5%).

Animals↗
PubMed1997

Relationship of human follicular diameter with oocyte fertilization and development after in-vitro fertilization or intracytoplasmic sperm injection.

The aim of this work was to evaluate the relationship between follicular size at the time of oocyte retrieval, and the subsequent oocyte competence to be fertilized and to develop in vitro. All the obtained oocytes were classified according to the corresponding volume of aspirated follicular fluid. Aspirated volume of follicular fluid <2 ml corresponded to a follicular diameter <16 mm and constituted the small size group. Volume of follicular fluid from 2 to 6 ml corresponded to a diameter from 16 to 23 mm and constituted the medium size group. The large size group contained follicles with diameter >23 mm and corresponded to an aspirated volume of follicular fluid of >6 ml. A progressive and significant increase in the rates of oocytes with a first polar body was observed from the small size group to the other groups and from the medium to the large size group: 75.3, 85.9 and 95.3% respectively. After classical in-vitro fertilization (IVF), significantly better rates of fertilization and development were obtained in the medium size group compared to the two other groups. Moreover, a positive relationship was observed between follicular diameter and rates of embryos scored as 'good' when oocytes were fertilized by intracytoplasmic sperm injection (ICSI). These results demonstrated that follicular size is positively related to the oocyte ability to be fertilized and to develop. Although oocytes from small follicles gave lower percentages of development probably due to partial oocyte incompetence, they allowed an increase in the total number of embryos scored as 'good'.

Cell Size↗
PubMed1996

Two essential steps for a successful intracytoplasmic sperm injection: injection of immobilized spermatozoa after rupture of the oolema.

A total of 740 cycles of intracytoplasmic sperm injection (ICSI) were performed: 625 cycles when < 6 x 10(5) total motile spermatozoa were harvestable from the ejaculate and 115 cycles in cases with a history of previous fertilization failure after classic in-vitro fertilization or subzonal sperm injection. An average of two pronuclei were observed in 63% of the injected oocytes, allowing 725 transfers of a maximum of three embryos (98%). Of 214 pregnancies initiated, 179 were established (25% of ICSI attempts). Because the fertilization rates from our initial 80 ICSI cycles were 2-fold less than those achieved previously, we changed the injection procedure and analysed, in 740 ICSI attempts, the importance of interfering technical factors and how to establish a successful ICSI programme. A remarkable change in the fertilization rate up to 68% (595 cycles) occurred when two steps in the injection procedure were performed well, i.e. immobilization of the spermatozoon and placement of the spermatozoon into the ooplasm after cytoplasmic aspiration into the pipette until oolema rupture. This immobilization, by touching the tail with the pipette, is mandatory for increasing the percentage of fertilization, even with totally non-motile spermatozoa (41%). Because aspiration of the cytoplasm is an invasive part of the ICSI procedure and influences the quality of the embryos, it is essential to reduce the amount of cytoplasm drawn into the pipette. This could be attained by using a spikeless injection pipette with the smallest possible internal diameter.

Cytoplasm↗
PubMed1996

High implantation and pregnancy rates with testicular sperm extraction and intracytoplasmic sperm injection in obstructive and non-obstructive azoospermia.

Thirty-two infertile couples with obstructive and non-obstructive azoospermia were included in this study. Testicular sperm extraction (TESE) was performed in 16 obstructive azoospermic cases where microsurgical sperm aspiration (MESA) or percutaneous sperm aspiration (PESA) were impossible because of totally destroyed epididymis and 16 non-obstructive azoospermia cases with severe spermatogenetic defect where the testicles were the only source of sperm cells. A total of 288 oocytes was obtained from 32 females and 84% were injected. The fertilization rates (FR) with 2 pronuclei (PN) and cleavage rate were 50.8 and 68.2% respectively. A total of 15 pregnancies was achieved (53% per embryo transfer), nine from the obstructive and six from the non-obstructive group. Four pregnancies resulted in clinical abortion (26.6%). The ongoing pregnancy rate was 39.2% per embryo transfer (ET) and 34.3% per started cycle. A high implantation rate was also achieved (26.6% in non-obstructive and 30% in obstructive azoospermia group). Using testicular spermatozoa in combination with ICSI in both obstructive and non-obstructive azoospermic groups, high implantation and pregnancy rates can be achieved.

Cytoplasm↗
PubMed1996

Fertilizing ability of immotile spermatozoa after intracytoplasmic sperm injection.

Sometimes spermatozoa from ejaculate, epididymis or testis show a total absence of motility. For some patients, however, very few spermatozoa with very poor motility can be found after several hours of incubation (initially immotile spermatozoa). Other samples show no motility at all even after extended culture (totally immotile spermatozoa). Intracytoplasmic sperm injection (ICSI) is the only method available to select and retrieve a single immotile or initially immotile spermatozoon and inject it into the oocyte. A total of 103 patients with asthenozoospermia underwent ICSI in this study. It was shown that initially immotile and totally immotile spermatozoa, whatever their origin, have the capacity to fertilize an oocyte after ICSI. No significant difference could be observed between the fertilizing capacity of testicular or epididymal spermatozoa. Totally immotile ejaculated spermatozoa, however, fertilized significantly fewer oocytes after ICSI when compared with initially immotile ejaculated spermatozoa. Embryos of lower quality tended to be produced when totally immotile spermatozoa of any origin were used, compared with embryos resulting from initially immotile spermatozoa. Ongoing pregnancies were conceived after ICSI with initially immotile spermatozoa from any origin and totally immotile spermatozoa retrieved from testis only. One biochemical pregnancy was the result of embryo transfer after ICSI with totally immotile ejaculated spermatozoa. No supernumerary embryos could be cryopreserved for patients with totally immotile spermatozoa from ejaculate or epididymis. For a Kartagener patient, subzonal insemination (SUZI) seemed to be a better approach for obtaining fertilization and pregnancy than ICSI because no fertilization occurred after ICSI on sibling oocytes. Hence a healthy pregnancy was obtained after SUZI.

Cryopreservation↗
PubMed1996

Fertility with testicular sperm extraction and intracytoplasmic sperm injection in non-obstructive azoospermic men.

In non-obstructive azoospermia spermatozoa can usually only be isolated from the testicles, and thus the most promising treatment model is testicular sperm extraction (TESE). Hormone concentrations, testicular volume determinations and testicular biopsy results are not uniform enough to select potential candidates for successful TESE and intracytoplasmic sperm injection (ICSI) approaches in advance. The aim of this study was to assess the efficacy of using ICSI with testicular spermatozoa in cases of non-obstructive azoospermia and to compare the inclusion criteria and sperm existence in the testicles in sperm obtainable and non-obtainable groups. All men showed either complete or incomplete (n = 14) maturation arrest in spermatogenesis, severe hypospermatogenesis (n = 10) or Sertoli cell-only syndrome (n = 5) in their testicular biopsies. Only 14 out of a total of 29 men provided enough spermatozoa for the ICSI procedure, while no spermatozoa were found in the testicular samples of the remaining 15 men. Out of 123 oocytes obtained from 14 females, 101 were injected with the husbands' testicular sperm cells. Total fertilization failure was observed in three cases. Of 39 oocytes fertilized, 38 cleaved. The fertilization and cleavage rates were 38.6 and 97.4% respectively. The pregnancy rate was 20.7% per initiated cycle. In the group from whom spermatozoa were obtainable, the pregnancy rate was 42.9% per initiated cycle and 54.5% per embryo transfer. A total of six pregnancies were achieved, of which two were twins and four were singletons. One singleton pregnancy resulted in abortion in the first trimester. There was no statistical difference concerning the serum follicle stimulating hormone concentration, testicular volume and biopsy results in groups in which spermatozoa were obtainable or not. In conclusion, although the association of TESE with ICSI obtained pregnancies for some patients with non-obstructive azoospermia, further studies are needed to determine the inclusion criteria for successful TESE.

Adult↗
PubMed1996

Pregnancies achieved with testicular and ejaculated spermatozoa in combination with intracytoplasmic sperm injection in men with totally or initially immotile spermatozoa in the ejaculate.

The efficacy of intracytoplasmic sperm injection (ICSI) employing testicular and ejaculated spermatozoa was assessed in 24 couples with totally or initially immotile spermatozoa. No criteria were employed in selecting which patients would be treated with testicular or ejaculated spermatozoa. The men were chosen at random. Testicular spermatozoa obtained by testicular sperm extraction were used in 14 and ejaculated spermatozoa were used in 10 of these couples. In all cases. asthenozoospermia was total in their basal semen sample. In 12 male partners, spermatozoa were totally immotile before and after Percoll gradient fractionation (totally immotile). In the remaining 12 men, spermatozoa initially showed a total absence of motility; however, some of the spermatozoa had showed very poor motility (0. 1%) after Percoll gradient fractionation and a 1.5-2.0 h incubation period (initially immotile). Of these 24 total asthenozoospermic males, 14 also had total teratozoospermia. The fertilization and cleavage rates in the testicular and ejaculated sperm groups were 53. 5 and 96.3 and 54.5 and 94.4% respectively. One cycle resulted in complete fertilization failure, and in 23 embryo transfer cycles a total of 10 pregnancies were obtained (41.6%). Eight pregnancies were achieved in the testicular sperm group, while only two pregnancies were obtained in the ejaculated sperm group. Four pregnancies, two from the ejaculated sperm group and two from the testicular sperm group, resulted in clinical abortions in the first trimester. Of the remaining six pregnancies, two have already resulted in healthy births and four pregnancies are now in the second or third trimester in the testicular sperm group. Using testicular spermatozoa in combination with ICSI can be an alternative mode of treatment in cases with totally or initially immotile spermatozoa in the ejaculate. Very low pregnancy rates have been obtained and no ongoing pregnancy has been achieved using ejaculated spermatozoa in these cases.

Adult↗
PubMed1995

Intracytoplasmic sperm injection, fertilization, and embryo transfer after retrieval of spermatozoa by testicular biopsy from an azoospermic male with testicular tubular atrophy.

OBJECTIVE: To achieve fertilization and cleavage by spermatozoa retrieved by testicular biopsy from a male with testicular tubular atrophy. DESIGN: Clinical trial. SETTING: Private reproductive institute. PATIENT: Azoospermic male with demonstrated testicular tubular atrophy and almost complete spermatogenic arrest. INTERVENTION: Open biopsy retrieval of testicular tissue and sperm followed by intracytoplasmic sperm injection. MAIN OUTCOME MEASURES: Fertilization and cleavage. RESULTS: One four- to six-cell embryo was formed after intracytoplasmic sperm injection of five eggs with extruded polar bodies by retrieved sperm. CONCLUSION: Intracytoplasmic sperm injection after testicular sperm aspiration may be attempted in cases with severely decreased spermatogenesis and result in fertilization, cleavage, and embryo transfer.

Adult↗
PubMed1993

Prevention of multiple pregnancies in an in vitro fertilization program.

OBJECTIVE: To limit the high number of multiple pregnancies in an IVF program. SETTING: In Vitro Fertilization Laboratory, Fertility Department, Public Hospital. INTERVENTIONS: The number of embryos transferred was limited to two instead of three. RESULTS: Limiting the number of embryos transferred to only two did not influence the take home baby rate but eliminated triplet and quadruplet gestations. Moreover, the number of patients with good quality supernumerary embryos available for cryopreservation increased. CONCLUSIONS: To reduce the high frequency of multiple gestations in an IVF program, the number of embryos replaced should be limited to a maximum of two.

Cryopreservation↗
PubMed1993

A monozygotic twin pregnancy after application of zona rubbing on a frozen-thawed blastocyst.

Assisted hatching techniques enhance the success rate of implantation of in-vitro fertilized human embryos. We report here the successful transfer of a frozen-thawed human blastocyst on which we applied a non-invasive zona rubbing technique (reduction of the thickness of the zona pellucida by gentle rubbing with a microneedle). The implantation in the uterus led to the delivery of healthy monozygotic twins.

Blastocyst↗
PubMed1992

Usefulness of partial dissection of the zona pellucida in a human in-vitro fertilization programme.

The influence of partial zona dissection (PZD) on the fertilization rate was studied in 34 couples with a history of fertilization failure and/or severe sperm deficiency. Overall, PZD improved the rate of monospermic fertilization compared to controls (41/254 versus 6/111: P less than 0.001) and fertilization was achieved in 50% of cases. However, the results differed according to the seminal characteristics. In 10 couples with at least two in-vitro fertilization (IVF) trials entailing total fertilization failure and with semen defined as normal, PZD did not significantly improve the monospermic fertilization rate (6/44 in the PZD group versus 2/39 among controls). A benefit related to PZD was evident in 33 attempts with severe sperm deficiency. In this group, only four of 72 unmanipulated control oocytes were fertilized but the monospermic fertilization rate was 14.6% for PZD oocytes. The rates of polyspermy were 40% and 14.6% in the groups with normal and abnormal semen parameters respectively. Of 33 trials with defective spermatozoa, 20 reached the stage of embryo transfer and three pregnancies were obtained, of which one aborted at 9 weeks.

Female↗
PubMed1982

The behaviour of cow blastocyst in vitro: cinematographic and morphometric analysis.

The behaviour of the cow blastocyst in vitro was studied by time-lapse cinematography and analysed by morphometry. Three types of behaviour were observed: continuous expansion followed by hatching; discontinuous expansion interrupted by few contractions and followed by hatching; discontinuous expansion interrupted by several rapid contractions without hatching. This demonstrated that the pulsatile activity of the blastocyst is not a necessary condition of hatching but also that only a moderate pulsatile activity is compatible with normal hatching. The time of hatching in vitro corresponded approximately with the time of zona loss in vivo (9-10 days). Rupture of the zona occurred at any point of the trophoblast layer. Hatching by herniation through a reduced opening of the zona was occasionally observed. The behavior of the embryos from a particular animal was very similar but differences were noted between embryos from different animals.

Animals↗
PubMedDate not supplied

Pregnancy obtained with human testicular spermatozoa in an in vitro fertilization program.

The fertilizing capacity of human testicular spermatozoa and the positive outcome of an in vitro fertilization program open a wide range of opportunities for men suffering from obstructive and inoperable azoospermia. In six cases, subzonal sperm injection or intracytoplasmic sperm injection techniques were applied to inject testicular spermatozoa into human oocytes. The fertilization rate after testicular sperm injection reached 45%. Normal cleavage was observed and replacement of 10 embryos in 6 patients resulted in one chemical and one ongoing pregnancy.

Cell Separation↗