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Biomedical subjects

R Menkveld

Publications and source records attributed to R Menkveld.

At least 55 records · Page 3Linked to original sources
PubMed1988

Evaluation of immunobead test (IBT), tray-agglutination test (TAT), and sperm immobilization test (SIT).

The present investigation relates the results obtained by the indirect immunobead test (IBT) to those found during the tray-agglutination test (TAT) and sperm immobilization test (SIT) performed on 16 positive blood sera samples. An IB binding of greater than 50% can be regarded as significantly positive (p less than 0.05), since 77% of the positive IB samples with an IB binding of greater than 50% also revealed a TAT titer of greater than 1:8. The IBT is an excellent test for the detection of sperm antibodies during routine screening procedures.

Agglutination Tests↗
PubMed1987

[Artificial intrauterine insemination with washed prepared spermatozoa of the husband].

Intra-uterine insemination with washed spermatozoa of the husband was evaluated in 42 infertile couples during 103 treatment cycles. A pregnancy rate of 47.3% was obtained after an average of 2 treatment cycles in a group of patients in whom hostile cervical mucus was the only known cause of infertility. A pregnancy rate of 21.7% was obtained after an average of 2.6 treatment cycles in a group of patients in whom low sperm morphology was the only known cause of infertility. The overall conception rate of 33.3% compares favourably with that in other published series.

Female↗
PubMed1987

A comparative analysis of grade 1 and grade 2 water in the Tygerberg Hospital in vitro fertilisation programme.

There are conflicting reports in the literature about the effect of the water source for growth and insemination media in an in vitro fertilisation (IVF) programme. A controlled trial was carried out in which two-cell mouse embryos were cultured in Ham F10 medium containing either grade 1 water (test group) or grade 2 water (control group). Of the two-cell embryos, 92.0% (69 of 75) in the test group and 91.8% (67 of 73) in the control group cleaved to the blastocyst stage (no statistically significant difference). On the basis of this experiment grade 2 water was used in the Tygerberg Hospital human IVF programme with good results. A continuing pregnancy rate of 23% per embryo transfer over a 1-year period is reported.

Animals↗
PubMed1986

Results of the in vitro fertilization programme at Tygerberg Hospital, phases II and III.

Phases II and III of the human in vitro fertilization programme at Tygerberg Hospital are presented. In phase II, 42 laparoscopies were performed and oocytes were obtained from 76% of the follicles aspirated, but with a fertilization rate of only 37%. The viable pregnancy rate per embryo transfer was 4%. Important changes took place in the programme, which led to a fertilization rate of 77% in phase III. Of the 78 patients subjected to laparoscopy, 65 (83%) reached the embryo transfer stage, resulting in a clinical pregnancy rate per embryo transfer of 23%, and with a 19% pregnancy rate per laparoscopy. The changes, methods and results of phases II and III are discussed.

Embryo Transfer↗
PubMed1986

Sperm morphologic features as a prognostic factor in in vitro fertilization.

To determine whether there is a prognostic value in the percentage normal sperm morphologic features in a human in vitro fertilization (IVF) program, the authors conducted a prospective study in women with bilateral tubal damage. Based on the percentage of morphologically normal spermatozoa, the patients were divided into four groups: group I, normal morphologic features between 0% and 14%; group II, 15% to 30%; group III, 31% to 45%; and group IV, 46% to 60%. One hundred ninety successful laparoscopic cycles were evaluated. In group I, 104 oocytes were obtained, of which 37% fertilized, but no pregnancy resulted; in group II, 81% of 324 oocytes were fertilized, with a pregnancy rate per embryo transfer (ET) of 22%; in group III, 82% of 309 oocytes were fertilized, with a 31% pregnancy rate; and in group IV, 91% of 69 oocytes were fertilized, with a pregnancy rate of 12%. Probability models indicated that there was a clear threshold in normal sperm morphologic features at 14%, with high fertilization and pregnancy rate in the groups with normal sperm morphologic features greater than 14%.

Embryo Transfer↗
PubMed1985

Osmolarity studies with different containers and volumes in a human in vitro fertilization programme.

In performing in vitro fertilization, a stable osmolarity in the medium surrounding the egg or embryo is of the utmost importance if a good fertilization and pregnancy rate is to be achieved. This study evaluated osmolarity changes in different volumes of fluid in the Falcon 3001 and 3037 Petri dishes and the Falcon 2058 tissue culture tube over a 24-hour period. It was found that the osmolarity was more stable in the Falcon 3037 Petri dish and in the tissue culture tube. The 3037 Petri dish was chosen for culturing human embryos.

Culture Media↗
PubMed1985

Results of phase I of the in vitro fertilization and embryo transfer programme at Tygerberg Hospital.

Phase I (3 June - 31 October 1983) of the in vitro fertilization (IVF) programme at Tygerberg Hospital is outlined in this article. This programme led to the birth of the first IVF baby in South Africa after fertilization and embryo transfer (ET) took place at this institution. The baby was born on 29 April 1984; a second baby was born on 20 June 1984. During phase I 24 laparoscopies were performed; 32 oocytes were obtained from 56 follicles, of which 62,5% were fertilized. Eleven ETs were performed, which led to 3 pregnancies. An ongoing pregnancy rate of 18% per ET and a pregnancy rate of 12,5% per laparoscopy were achieved.

Adult↗
PubMed1985

The effect of surgical glove powder on cleavage of two-cell mouse embryos in an in vitro fertilization programme.

The effect of surgical glove powder on the development of early mouse embryos was studied. Embryos from F1 hybrid mice (C57 B1/6 X CBA) were suspended in Whittingham's T6 growth medium with 10% human serum, using Petri dishes (Falcon 3001). Contamination was brought about by a sterile, powdered, surgical glove touching the surface of the growth medium for less than a second in group I, and in group II the same procedure was followed but the glove was rinsed beforehand with sterile, four times distilled water and air-dried. In the control group (group III) no contamination with surgical glove powder occurred. In group I only 9 of 137 embryos (7%) reached the blastocyst stage, in contrast with 110 of 196 (56%) in group II and 258 of 287 (90%) in group III. The differences in results between groups I and III, groups I and II, and groups II and III were found to be statistically significant (P less than 0,001) by the chi-square test. It is concluded that surgical gloves are a potent inhibitor of early embryonic growth. In an in vitro fertilization programme including follicle aspiration and embryo transfer, contamination of embryos with these gloves should be avoided at all costs.

Animals↗
PubMed1984

Chromosome studies in 496 infertile males with a sperm count below 10 million/ml.

Chromosome studies were performed on 106 men with azoospermia and 390 men with oligozoospermia (consistent sperm count below 10 million/ml). Constitutional chromosome abnormalities were found in 14.1% of the azoospermia group and in 5.1% of the oligozoospermia group. An overall incidence of 7.1% constitutional abnormalities indicates that this criterion of selection may be advisable for routine chromosome analysis of infertile men. A reduction of 25% in the workload increases the yield of chromosome abnormalities in the group of infertile men to 10-14 times above that expected in the normal population.

Chromosome Aberrations↗
PubMed1980

[A comparative study of the white cell pipette method and the Makler counting chamber method of counting spermatozoa].

A new method for counting spermatozoa was introduced by Makler. This method was compared with the white blood cell pipette method and the results revealed high precision and accuracy (difference of means = 5,9%). Makler's method, which is very simple to perform, has the advantage that rapid and reliable sperm counts can be done. Therefore, the Makler counting chamber can be used with confidence in the performance of semen analysis by any doctor or in any laboratory.

Humans↗
PubMed1975

Oligozoospermia: a seven-year survey of the incidence, chromosomal aberrations, treatment and pregnancy rate.

No sperm count should be regarded too low to consider extensive treatment in order to improve semen or to correct any possible abnormalities in femal partners. The infertile couple should be given devoted care and advice to improve their sexual relations and their psychological attitude towards the problem of infertility. A pregnancy rate of 51.9% where the husband's count was less than 10 million/ml, offers adequate support for this statement. In cases of mental trauma inflicted on patients by a verdict of inability to achieve parenthood--on people who have already suffered severe psychological shock and tension resulting from a period of infertility--discouragement lessens the already doubtful chances of achieving pregnancy. In no circumstance should oligozoospermic patients receive treatment for infertility unless a chromosomal analysis has been completed and found normal, since our rate of chromosomal anomalies (11.4%) in a group of oligozoospermic patients is considered to be too high.

Cell Count↗
PubMedDate not supplied

Validation of a new disposable counting chamber.

In a routine prospective study, 3 different counting chambers were compared for manual and computer-assisted evaluations. Swim-up samples were used so as to remove all debris and other cells that may contaminate the evaluation process when using a semen analyzer. The Makler concentration determinations (n = 20) were, on average. approximately 20 x 10(6) cells/mL higher compared to the corresponding 20 hemocytometer counts. The mean differences between the Leja chambers and the hemocytometer counts (n = 320) were only around 1 x 10(6) cells/mL, with coefficients of variation around 20%. The Leja chambers for both manual and the computer-assisted sperm concentration determinations provided consistent and accurate data on sperm concentration.

Humans↗
PubMedDate not supplied

A possible increase in the number of metaphase I spermatocytes in testicular biopsy of infertile men with chromosomal aberrations.

During the histological investigation of testicular biopsy of patients with chromosomal aberrations, it was observed that in some of these patients more of the primary spermatocytes were in metaphase I, in comparison with normal testicular biopsy where, according to our investigations, these cells are only seen occasionally. A possible explanation for this phenomenon, which was mainly observed in patients with autosomal chromosome aberrations, is given.

Biopsy↗
PubMedDate not supplied

A statistical comparison of three methods for the counting of human spermatozoa.

Three methods for the counting of human spermatozoa were compared and evaluated. Firstly the white blood cell pipette and hemocytometer method was used. For the second method the Makler counting chamber was used and the results of the third method were obtained by using a glass tuberculin syringe instead of the white blood cell pipette for diluting purposes. The tuberculin syringe is the standard method used in this laboratory. The tuberculin method showed a high degree of precision and accuracy, especially when compared to the makler counting chamber method. Through a simultaneous pairwise linear structural relationships analysis, whereby an error variance was estimated for each method, it was found that the tuberculin syringe method was the most accurate followed by Makler's method, and then the white blood cell pipette method.

Humans↗
PubMedDate not supplied

Comparison of a discontinuous Percoll gradient method versus a swim-up method: effects on sperm morphology and other semen parameters.

Increasing the proportion of motile and normal spermatozoa is an important objective for assisted reproductive procedures. The aim of this study was to compare the results of a Percoll and swim-up-method, especially on the sperm morphology. The Percoll technique gave a recovery rate of 81.3% of motile spermatozoa against a recovery rate of 28.98% for the swim-up technique. When the percentage of normal spermatozoa was also brought into calculation the recovery rate with the Percoll technique decreased to 62.03% and increased to 31.81% for the swim-up technique. This was due to a decrease in the resultant morphology of the Percoll technique to a median of 8.0% and an increase to 11.5% for the swim-up technique from a median of 10.5% of the original samples.

Centrifugation, Zonal↗
PubMedDate not supplied

Assisted reproductive technologies may obviate apparent immunologic infertility.

Spermatozoal autoantibodies have been associated with reduced fertilization by natural coital methods. Nine subfertile men were evaluated who repeatedly tested positive for spermatozoal autoantibodies as characterized by direct immunobead test. Using the hemizona assay, we determined whether tight binding of spermatozoa to the zona pellucida was reduced in these test males as compared to a fertile male whose semen had been cryopreserved and thawed immediately prior to testing. The average number of spermatozoa tightly bound to the zona pellucida from the subfertile male was significantly reduced compared to the fertile male (mean +/- SD, P less than or equal to 0.01) 19.5 +/- 8 versus 77.1 +/- 49. Seven of the nine couples eventually had successful fertilization using intrauterine insemination or gamete intrafallopian tube transfer and one couple conceived with natural coital insemination. Our findings, albeit limited, suggest that greater caution should be used in implicating associations of spermatozoal autoantibodies with absolute infertility, because novel assisted reproductive technologies often may obviate conventional encumbrances on opportunities for pregnancy.

Adult↗
PubMedDate not supplied

Glass wool filter preparation of cryopreserved spermatozoa.

Oligozoospermic and asthenozoospermic semen ejaculates, as well as cryopreserved sperm samples prepared by the wash and swim-up procedure often result in unsatisfactory sperm recovery rates. In this study the glass wool filter and the wash and swim-up preparation procedures were compared on the basis of their 'effective' (number of live sperm per millilitre) recovery rates. The glass wool filter procedure consistently produced significantly (P = 0.0002) higher viable sperm concentrations, making it the preferred method for the preparation of cryopreserved sperm to be used in assisted reproduction techniques. The use of this preparation procedure has also been shown to have no adverse affect on the fertilizing potential of human spermatozoa in our unit.

Cryopreservation↗