Biomedical subjects

T F Kruger

Publications and source records attributed to T F Kruger.

At least 109 records · Page 6Linked to original sources

PubMed1985

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

Two different protocols for ovulation induction used in phase I of the in vitro fertilization (IVF) programme at Tygerberg Hospital are presented. Previous experience with gonadotrophins and clomiphene citrate was applied in the development of the protocols. By means of experience gained during ovulation induction it was possible to establish critical values for the parameters of follicle maturity, which are used to determine the optimal time for follicle aspiration. Ultrasonically measured follicle size, critical serum oestradiol levels for each mature follicle and cervical mucus scoring were the parameters used. Fifty-one ova were obtained during 29 of the 34 attempts at follicle aspiration. Only 5 of the ova were immature. At least 1 mature ovum was obtained at 80% of all laparoscopies. Twenty-three embryos were transferred to 15 patients, and 3 pregnancies occurred. As a result of this programme 2 babies were born--the first in South Africa by IVF and embryo transfer.

Clomiphene↗

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

The role of hexoprenaline in suprapubic amniocentesis during late pregnancy. A pilot study.

Suprapubic amniocentesis is often complicated by the fetal head being fixed in the pelvis, oligohydramnios or a hyperirritable myometrium. These factors limit the success rate associated with the procedure. If the myometrium is relaxed with a beta 2-stimulant, a higher success rate may be achieved. This was investigated in a randomized, prospective, double-blind pilot study using hexoprenaline. When four- or five-fifths of the fetal head was palpable above the pelvis, hexoprenaline (17 amniocenteses) showed no advantage over a placebo (16 amniocenteses). However, when three-fifths or less of the fetal head was palpable above the brim, 4 dry taps were obtained in the control group using a placebo (17 amniocenteses), while none occurred in the study group (19 amniocenteses) (P less than 0,05). Elevation of the fetal head was less difficult in the study group, but this difference was not statistically significant. These results suggest that hexoprenaline is not indicated for routine use during amniocentesis. When a dry tap is obtained or when marked difficulty is encountered in lifting the fetal head from the pelvis, 10 micrograms hexoprenaline administered intravenously 5 minutes before amniocentesis appears to facilitate successful completion of the procedure. However, a larger series is necessary to confirm this observation.

Adolescent↗

PubMed1984

[A comparative study of two-cell embryos of CBA and F1 mice in a human in vitro fertilization program].

The two-cell mouse embryo can develop in a chemically defined medium to the blastocyst stage but conditions must be strictly controlled. Fresh T6 (Whittingham's) medium is being used weekly for this purpose in our laboratory and subjected to a 5% CO2-in-air system 24 hours prior to use. Experiments were designed to determine whether two-cell embryos obtained from an F1 (CBA X C57/B1/6) X F1 cross were superior to the easily obtainable CBA X ICR cross. The aim was to get a 90% blastocyst result for use as a quality control. Eight experiments were performed over a 6-week period. The CBA two-cell embryos were compared with the F1 group under identical conditions. A total of 177 two-cell embryos were obtained from the CBA group and 214 two-cell embryos from the F1 group. In the CBA group 51 developed to the blastocyst stage (28.8%) compared with 187 in the F1 group (87.4%) (P less than 0.0001). In conclusion, it is advisable to obtain F1 mice to use weekly in the laboratory as a quality control measure. The CBA group yields poor cultures, and this leads to unnecessary laboratory confusion.

Animals↗

PubMedDate not supplied

Surrogate pregnancies in patients with Mayer-Rokitansky-Kustner-Hauser syndrome and severe teratozoospermia.

The challenge of the case presented was threefold: congenital absent uterus (Mayer-Rokitansky-KustnerHauser syndrome), a request for surrogacy, and teratozoospermia in the husband (6% normal morphology according to the Tygerberg strict criteria). Surrogacy was dealt with by means of guidelines proposed by the SA Law Commission after a surrogate mother was found. The gestational carrier was synchronized with the genetic donor with congenital absent uterus, the main aim being assisted reproduction. Two gamete intrafallopian transfer (GIFT) procedures were performed, both unsuccessful. Poor fertilization of excess GIFT oocytes was also observed. Three intracytoplasmic sperm injection procedures were then performed. The first two were unsuccessful and the third ensued in a singleton pregnancy. Hormonal support (progesterone and estradiol valerate until 12 weeks pregnancy duration) was given. The pregnancy resulted in the normal delivery of a healthy male infant at full term. Psychological support was given to mother and surrogate throughout pregnancy, as well as thereafter. The success of this case gives hope to infertile couples with severe infertility factors.

Adult↗

PubMedDate not supplied

The role of sperm morphology in assisted reproduction.

This article attempts to evaluate the value of sperm morphology in assisted reproduction by summarizing a recent structured literature review covering the topic. New developments in the field of sperm morphology with emphasis on computer evaluation of morphology and its latest clinical application are highlighted, as well as the correlation between sperm functional tests and sperm morphology. Based on the correlation between the sperm functional tests and sperm morphology, as well as the latter's proven value as a predictor in in-vitro fertilization, one can assume that sperm morphology reflects function, although based on definition it is not a sperm functional test per se. The evaluation of sperm morphology by strict criteria is a simple, cost-effective method and can be used to guide the clinician and scientist on a day-to-day basis to make sound clinical decisions.

Female↗

PubMedDate not supplied

Predictive value of normal sperm morphology in intrauterine insemination (IUI): a structured literature review.

The aim of the study was to conduct a structured review of the literature published on the use of normal sperm morphology, as an indicator of male fertility potential in intrauterine insemination (IUI) programmes. Published literature in which normal sperm morphology was used to predict pregnancy outcome in IUI during the period 1984-1998 was reviewed. In total, 421 articles were identified via Medline searches. Eighteen provided data that could be tabulated and analysed. Eight of the analysed studies provided sufficient data for statistical analysis, six studies used the Tygerberg 'strict' criteria, and two the WHO guidelines (1987, 1992). A meta-analysis of the six studies in the strict morphology group yielded a risk difference (RD) between the pregnancy rates achieved in the patients below and above the 4% strict criteria threshold of -0.07 (95% CI: -0.11 to 4.03; P<0.001). The WHO criteria group (1987, 1992) had insufficient data to be analysed. Meta-analysis showed a significant improvement in pregnancy rate above 4% threshold for strict criteria. Accurate evaluation of normal sperm morphology results should be an integral part of evaluating the male factor.

Female↗

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

Electron microscopic evidence on the acrosomal status of bound sperm and their penetration into human hemizonae pellucida after storage in a buffered salt solution.

The hemizona assay (HZA) was developed to evaluate sperm binding potential using microbisected human zona pellucida. In this study, eight human oocytes stored in a buffered salt solution for 60 days were bisected into two identical hemispheres (hemizonae) and coincubated with the spermatozoa from a fertile man. All evaluated spermatozoa were tightly bound to the outer surface or had begun penetration into the zona pellucida. The hemizonae with bound spermatozoa were prepared and fixed for transmission electron microscopy (TEM) using standard techniques. Among the 108 sperm bound to the zone we were able to evaluate 25 by TEM. Twenty (80%) of the zona bound spermatozoa were partially or completely acrosome reacted, while six (20%) of the zona bound sperm had intact acrosomes. Acrosome intact, partially acrosome reacted and completely reacted spermatozoa were observed within the zona. Penetration pathways or tunnels were seen within the zona matrix. The results illustrate, that typically spermatozoa tightly bound the human zona pellucida show induction of the acrosome reaction. Importantly, following storage of human eggs in salt solution (buffered to 7.4), the zona pellucida retain their biological and functional characteristics for at least 90 days.

Acrosome↗

PubMedDate not supplied

The hemizona assay (HZA) as an experimental model to evaluate the inhibition of sperm binding to the murine zona pellucida by isolated zona pellucida protein.

Compelling evidence has demonstrated that zona binding represents gamete recognition by sperm binding with high affinity and specificity to complex glycoproteins of the zona pellucida. In the present study we evaluated the hemizona assay (HZA) in the investigation of the interaction of mouse spermatozoa with unfertilized murine oocytes and hemizonae after exposure to solubilized murine zonae pellucidae proteins. The zonae pellucidae were isolated from ovarian tissue following described mincing techniques. The sperm binding characteristics of murine spermatozoa were studied by using SDS-PAGE isolated ZP2 (+/- 120 Kd) and ZP3 (+/- 83 Kd) components of the zona pellucida. Sperm receptor activity was examined in a competitive gamete binding fashion using the HZA as an indicator of sperm/zona interaction. The results illustrated that isolated, solubilized ZP2 and ZP3 glycoprotein moieties of the zona pellucida inhibited sperm binding to hemizonae and oocytes when compared to controls, and that the HZA can be utilized as an internally controlled homologous bioassay to evaluate the effects of zona pellucida proteins on tight binding of spermatozoa to the zona pellucida.

Animals↗

PubMedDate not supplied

Effect of multiple centrifugations on the evaluation of the acrosome reaction in human spermatozoa.

This study was undertaken to assess the effect of multiple centrifugations on the human acrosome reaction and in vitro fertilizing ability. Semen samples were obtained from sperm donors and from patients participating in our in vitro fertilization programme. Measured sperm samples were centrifuged twice (400xg for 5 min) before or after the induction of the acrosome reaction with calcium ionophore A23187 and before the insemination of oocytes. The samples obtained from the sperm donors were used to measure the acrosomal loss by means of indirect immunofluorescence (T6 monoclonal antibody) and the patient samples were used to assess fertilizing ability and cleavage. Samples centrifuged twice before the chemical induction of the acrosome reaction exhibited significantly elevated levels of acrosomal loss (mean = 46%) as compared to the controls (23%). However, the fertilization (P = 0.688) and cleavage (P = 0.187) rates were not significantly different between the controls and the centrifuged samples. The present study has shown that the centrifugation of motility enriched (swim-up) samples may also modify the acrosomal membrane complex, without compromising fertilizing potential.

Acrosome↗

PubMedDate not supplied

The relationship between morphology, motility and zona pellucida binding potential of human spermatozoa.

Prediction of the fertilizing potential of human gametes under in vitro conditions has been a major field of interest of assisted reproductive programmes. However, sperm morphology has been regarded as a predictor of human in vitro fertilization rate. This paper prospectively evaluates the relationships among normal sperm morphology and (1) motion characteristics viz. curvilinear velocity (VCL), straight line velocity (VSL), and linearity (LIN) (n = 37) and (2) sperm-zona pellucida binding capacity under HZA conditions (n = 144) of two separate groups of infertile couples. Semen was evaluated for sperm concentration, percentage motility, forward progression, and percentage normal morphology (strict criteria). The motility characteristics were measured using a computerized Sperm Motility Quantifier (SMQ). The zona binding potential of sperm was evaluated using the hemizona assay. Firstly, the VCL significantly differed between the P-pattern and both the G (72.9 +/- 7 vs. 86.3 +/- 16 microns s-1; P = 0.04) and N patterns (72.9 +/- 7 vs. 91.0 +/- 15 microns s-1; P = 0.002). The VSL differed only between the P and N patterns, being 19.7 +/- 7 vs. 32.6 +/- 15 microns s-1 (P = 0.02), respectively. No significant differences in LIN were noted between any of the three patterns. The sperm concentration differed significantly between the P and both the G (37.9 +/- 35 vs. 80.8 +/- 9 x 10(6) ml-1; P = 0.03) and the N patterns (37.9 +/- 35 vs. 89.7 +/- 72 x 10(6) ml-1; P = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMedDate not supplied

Wheat germ agglutinin receptors on human sperm membranes and sperm morphology.

Sperm membrane components play an important role in the determination of sperm fertilizing ability. During spermatogenesis, epididymal transit, and capacitation, the sperm membrane undergoes various subtle changes which are important maturational events for the production of viable spermatozoa and hence partly determine fertility. Localization and intensity of wheat germ agglutinin (WGA) receptors are reported to be directly associated with male fertility. We examined the correlations and differences between the distribution patterns and intensities of WGA receptors of 75 semen samples, classified according to the strict criteria described for sperm morphology, namely P-pattern (0-4% normal forms, n = 19), G-pattern (5-14% normal forms, n = 41) and normal samples (> 15% normal forms, n = 15). Results indicate distinct differences in WGA receptor intensity in all of the three groups as well as significantly (P < 0.05) lower per-cent staining of the equatorial segment amongst the P-pattern group when compared to the other two groups. It would appear that there is a close relationship between WGA receptors on human sperm membranes and sperm morphology.

Cell Membrane↗

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↗

PubMedDate not supplied

Sperm decondensation and semen parameters: utilization of a simple staining technique for the evaluation of human sperm decondensation.

The ability of spermatozoa to fertilize an oocyte depends on a sequence of events ending ultimately in the decondensation of the sperm chromatin on penetration of the oocyte. Knowledge of what percentage of sperm decondenses is useful, especially in patients where other functional tests and sperm quality fail to explain the reported poor in vitro fertilization (IVF) rates. The objective of this study was (1) to compare sperm decondensation induced by either SDS/EDTA or heparin with semen parameters (volume, concentration, motility and morphology), and (2) to evaluate the use of a simplified staining technique (Diff QuikR [DQ]) in comparison with the standard phase contrast method (Rose Bengal-[RB]). Randomly selected semen samples from 31 men attending an assisted reproductive programme were analysed for basic semen parameters and decondensation with SDS/EDTA and heparin. Two staining methods for the evaluation of decondensation were compared (phase contrast microscopy after Rose Bengal [RB] staining and light microscopy after Diff QuikR (DQ) staining). Moderate and grossly swollen sperm heads were recorded. Semen samples included both fertile and unfertile semen parameters. Sperm decondensation results showed poor to moderate correlations with semen parameters. The SDS/EDTA (DQ) (moderate forms) showed a significant negative correlation (r = -0.46) with seminal volume and a significant positive correlation (r = 0.41) with normal sperm morphology. The heparin (DQ) (moderate forms) decondensation showed a significant positive correlation with motility (r = 0.61) and sperm concentration (r = 0.43). The DQ method was preferred over the RB method due to its optical and storage advantage.(ABSTRACT TRUNCATED AT 250 WORDS)

Azure Stains↗

PubMedDate not supplied

Sperm-oocyte interaction: studies on the kinetics of zona pellucida binding and acrosome reaction of human spermatozoa.

Successful sperm-oocyte interaction depends, among other things, on sperm capacitation, which is defined by acrosomal and motility alterations. In the study described here the authors evaluated different aspects of this gamete interaction in humans. Specifically, the authors studied (1) the relationship between the number of spermatozoa bound to the zona pellucida and sperm concentration and incubation period, (2) the capacitation status and kinetics of acrosome reaction among the zona-bound spermatozoa, and (3) the effect of human follicular fluid on the zona-binding potential and acrosome status of spermatozoa from different men. The results indicated a concentration of 10(7) cells ml-1 after 15 min of coincubation to be the optimum for zona binding. The number of sperm bound after 0, 3 and 5 h of incubation was the same. In addition, spermatozoa incubated for 3 or 5 h underwent the acrosome reaction (range 9-43%) on the zona surface within 15 min of binding. The maximum percentage of acrosome-reacted spermatozoa was reached after 60 min of binding. Follicular fluid affected the sperm populations selectively, since it did not influence zona binding capacity in all cases. The data enhances the authors' understanding of critical events occurring before fertilization.

Acrosome↗

PubMedDate not supplied

Sperm binding capacity of human zona pellucida derived from oocytes obtained from different sources.

The important contributions of sperm-oocyte interaction to infertility diagnostics is well established. Scientists are urged to search for methods to improve the assessment of gamete interaction. Sperm binding and penetration assays have frequented the literature, reporting on various aspects of sperm-oocyte interaction using either microbisected or whole human oocytes during the assay procedure. The objective of the study was to evaluate additional zona pellucida sources which can be used during zona binding studies. Hemizonae were obtained from the following oocytes: 1) experiment 1, prophase I oocytes from post-mortem ovarian tissue from different age groups namely, 7 months, 5 years, 7 years, 12 years and 30 years; 2) experiment 2 used donated immature Prophase I oocytes from the IVF treatment program and 3) experiment 3 evaluated zona binding for hemizonae which were previously used in hemizona assays. Results indicated that, in experiment 1, ovarian age does not have any influence on the zona pellucida's capacity to bind spermatozoa. The mean number of bound sperm among the different age groups did not differ significantly, namely 38.9 +/- 17 (7 months), 31.0 +/- 27 (5 years), 49.3 +/- 21 (7 years), 32.8 +/- 18 (12 years) and 39.5 +/- 17 (30 years). The pooled mean +/- SD binding for all the age groups in experiment 1 was 37.7 +/- 7. Likewise, the mean number of sperm bound (experiment 2) to zonae collected from oocytes using different ovulation induction regimes were 31.1 +/- 20 (unstimulated), 54.4 +/- 12 (HMG/HCG) and 15.3 +/- 9 (HMG alone).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

The influence of a mineral oil overlay on the zona pellucida binding potential of human spermatozoa.

The objective of the study was to evaluate the effect of mineral oil on zona pellucida binding potential of human spermatozoa. The study compared zona binding using micro volume droplets under mineral oil as apposed to micro droplets in cryopreservation straws. Spermatozoa from eight proven fertile sperm donors were used. One hundred and fifty five matched hemizonae in 50 microliters, 100 microliters and 200 microliters insemination sperm droplets were co-incubated; (i) under mineral oil and (ii) 0.5 ml plastic cryopreservation straws. The results were analysed to determine the number of the zona bound spermatozoa during each experiment. Microvolumes with an oil overlay had a decrease in sperm bound per hemizona of 38% (mean +/- SD; 563 +/- 415 vs. 921 +/- 597), 51% (mean +/- SD; 392 +/- 359 vs. 800 +/- 566 sperm) and 18% (mean +/- SD; 502 +/- 369 vs. 618 +/- 445) in 200 microliters, 100 microliters and 50 microliters respectively, compared to microvolumes in cryopreservation straws. It was concluded that mineral oil may have some detrimental factors which interfere with zona binding of spermatozoa.

Cryopreservation↗