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J P Geraedts

Publications and source records attributed to J P Geraedts.

At least 19 recordsLinked to original sources
PubMed1992

Recovery and identification of DNA sequences harboured in preserved ancient human bones.

A new method is presented to extract and identify specific DNA fragments from well preserved human bones, dating from three different time periods. Bone samples were thoroughly freed from surfacial contaminating DNA. Access to the inner bone spongiosum was achieved by removing the covering bone layers of the vertebra or sternum, whereas the patella, tibia and caput of the femur or humerus were cleaved with an iron saw. After the spongiosum was taken out, extraction of nucleic acids from this "sand" like material was performed by heating at 94 degrees C during 20 min in a buffer containing essentially minor concentrations of detergent, chelating and reducing agents. The extracts were used in various Polymerase Chain Reaction (PCR) protocols to amplify different human specific DNA fragments (originating from chromosomes X and 12). From 15 out of 20 bone samples human-specific gene fragments could thus be identified.

Base Sequence↗
PubMed1992

Comparison between the hypoosmotic swelling test and morphology evaluation using strict criteria in predicting in vitro fertilization (IVF).

BACKGROUND: The role of male factor with respect to sperm morphology, progressive motility, and density is studied under in vitro conditions. METHODS: The semen samples of 67 males participating in an in vitro fertilization program were evaluated by the conventional WHO criteria of spermatogram, by morphology evaluation using strict criteria (MEUSC), and by the hypoosmotic swelling test (HOST). All sperm tests were performed in the original semen sample as delivered on the day of IVF, before further sperm treatment. The correlations between these parameters and the fertilization outcome were evaluated and their predictive values were calculated. RESULTS: When the patients were divided into two groups, namely, fertile (fertilization rate per oocyte greater than 0%) and infertile (fertilization rate per oocyte = 0%), only mean sperm density and morphology were significantly different between the groups (P less than 0.05). The correlation with fertilization rate in vitro was in favor of MEUSC. CONCLUSIONS: Our results show that the HOST is inferior to MEUSC and conventional WHO sperm analysis in predicting fertilization in vitro.

Cell Membrane↗
PubMed1992

Triploidy after in vitro fertilization: cytogenetic analysis of human zygotes and embryos.

Tripronuclear zygotes obtained from a clinical IVF program were studied cytogenetically. Successful analysis was possible of 42 specimens at the zygote stage and 21 embryos after the first or second cleavage division. In the majority of zygotes (88%) the expected triploidy was confirmed, whereas only 14% of embryos had solely triploid cells. Therefore it is concluded that after tripolar cleavage division, many different types of mosaicism may originate from irregular chromosome distributions. Since the findings in individual blastomeres in embryos resulting from multipronuclear zygotes do not reflect the genetic content of the whole embryo, these embryos are less suitable in a model system for preimplantion diagnosis. The distribution of the sex chromosomal types (XXX, XXY, and XYY) confirmed theoretical expectations. Since in abortion material or in liveborn triploidy cases, the XYY karyotype is hardly ever observed, this indicates that most likely the 69,XYY karyotype has a very high embryonic mortality.

Clomiphene↗
PubMed1992

Temporal effects of taurine on mouse preimplantation development in vitro.

Previously it has been shown that significantly more 2-cell mouse embryos reach the blastocyst stage when cultured in medium supplemented with taurine. In this study, in-vitro fertilized zygotes from a hybrid mouse strain were used to examine the temporal effects of 10 mM taurine on embryonic development in vitro during the preimplantation period. Taurine exerted its beneficial effect exclusively during the first 2 days post-insemination. The effect of taurine on blastocyst formation appeared to be restricted mostly to the period 20-48 h after fertilization, during which time mouse embryos are at the two-cell stage. Although more blastocysts were found when embryos were cultured in taurine-containing medium from 5 to 20 h post-insemination, this difference was not significant compared to the number of blastocysts when embryos were cultured without taurine. Taurine did not appear to affect the two-cell block of mouse embryos from random-bred strains.

Animals↗
PubMed1992

Effect of the number of inseminated spermatozoa on subsequent human and mouse embryonic development in vitro.

It has been shown, in both human and mouse in-vitro fertilization (IVF), that an excess number of spermatozoa in the insemination medium leads to reduced fertilization rates. In this study, we evaluated human embryonic development after dividing the oocytes of each of 62 IVF attempts into two groups on the basis of insemination with two widely used concentrations (50,000 and 100,000 spermatozoa/ml). The embryonic growth was retarded in the group inseminated with 100,000 spermatozoa/ml: significantly fewer fast developing embryos (4-cell and 5- to 8-cell stages) were found (53.4% in the 100,000/ml group and 65.5% in the 50,000 group; P less than 0.05). In two experimental series, mouse embryonic development was evaluated in the presence of 0, 50,000, 100,000 and 500,000 spermatozoa per ml. In the first series, the spermatozoa were present during 5-20 h after insemination, while in the second series, the spermatozoa were present during the whole culture period of 120 h. The development of mouse embryos was impaired when 500,000/ml spermatozoa were present during the whole culture period. In contrast with human IVF results, the presence of up to 500,000 spermatozoa during the first 20 h after insemination did not have any significant detrimental effect on blastocyst formation in the mouse.

Animals↗
PubMed1992

Male factor as determinant of in-vitro fertilization outcome.

The effect of different semen parameters was evaluated in 200 consecutive couples in an in-vitro fertilization (IVF) programme. All semen analyses were performed on the native aliquot of semen which was subsequently prepared and used for in-vitro insemination. Morphology evaluation using strict criteria (kappa 0.46 and r = 0.565) was compared with progressive motile sperm density (kappa 0.37 and r = 0.333) and the conventional World Health Organisation (WHO) evaluation of morphology (kappa 0.31 and r = 0.378). Results show that morphology evaluation using strict criteria is the best predictor of IVF and density of progressively motile spermatozoa can be an optional method. The combined results of strict morphology and motile concentration progressively showed that if both parameters were below the cut-off points of 5% and 3 x 10(6)/ml respectively, the fertilization rate per oocyte was very low (18%). No pregnancies were achieved in this group. When both parameters were above the cut-off points, the fertilization rate per oocyte was high (72%) (P less than 0.005) and the pregnancy rate per embryo transfer was 27%. Predictive values indicate that morphology evaluation using strict criteria and the number of progressive motile spermatozoa can be used as patient selection criteria for infertility clinics.

Embryo Transfer↗
PubMed1992

Chromosomal localization of transfected genes by a combination of hot banding and fluorescence in situ hybridization.

We describe the combination of hot banding with fluorescence in situ hybridization as a rapid and efficient method to identify integration sites of transfected DNA sequences in chromosomes. As a test system we used SW480 EJ2, a clonal cell line obtained after transfection of SW480 with pSV2neoEJ, a plasmid containing a point-mutated, c-Ha-RAS oncogene. Nick-translated probes were compared with random primed-labeled probes to evaluate their relative efficiency in fluorescence in situ hybridization. The fluorescence signals were quantified in interphase nuclei by confocal scanning laser microscopy. Nick-translated probes were found to yield better results. Hot banding followed by fluorescence in situ hybridization localized the integration site of pSV2neoEJ in SW480 EJ2 at the site of a translocation on a marker chromosome Xp+. The combination of fluorescence in situ hybridization and hot banding can be used to (a) rapidly and efficiently analyze integration sites in large numbers of transfectants, (b) assess the clonality of transfected cell lines, and (c) localize the site of integration of transfected genes in the recipient genome.

Animals↗
PubMed1992

Positive effect of taurine on preimplantation development of mouse embryos in vitro.

The effect of various taurine concentrations in modified Tyrode's medium on in vitro fertilization of mouse oocytes was examined. No significant difference in fertilization rate was found at concentrations of 0, 0.1, 1, 5, 10 and 20 mM taurine. In a second series of experiments, the effect of taurine on preimplantation embryonic development after fertilization in vitro was studied. At concentrations of 1, 5, 10 and 20 mM taurine, significantly more two-cell embryos reached the blastocyst stage compared with medium without taurine. Culture in the presence of 5 mM or 10 mM taurine resulted in blastocysts with the highest mean number of cells. The positive effect of taurine on embryonic development was found to be more pronounced both in a second medium (human tubal fluid medium) which has a higher potassium concentration than Tyrode's medium, and in a modified Tyrode's medium with an increased potassium concentration. In addition to these in vitro studies, it is reported that taurine comprised about 59% of the total free amino acid content in mouse oviduct flushings, compared with 17% in mouse serum.

Amino Acids↗
PubMed1991

[Women's opinion concerning oocyte donation for pre-embryonic studies].

For the benefit of pre-embryonal research, women requesting sterilization may be asked whether they are prepared to donate egg cells. Recently, a questionnaire was sent to 144 women who had given birth to their second or third child at the University Hospital Groningen, asking them how they felt about egg cell donation: 68 (47%) of the questionnaires was returned. Of the respondents 45 (66%) felt that a request for donation could be made to women who were admitted to hospital for sterilization. 22 (32%) of the respondents said they would be willing to donate an egg cell themselves. Of these women, 10 said they would be willing to use hormone preparations for this purpose.

Female↗
PubMed1991

Nonisotopic in situ hybridization as a method for nondisjunction studies in human spermatozoa.

Human spermatozoa were studied with a nonradioactive in situ hybridization method. Using a chemically modified DNA probe and immunocytochemical reactions for visualization, it was possible to obtain hybridization signals in 31 of 32 semen samples. Positive hybridization reactions, depending on cell accessibility, varied from 40% to over 90% for the different samples. Using a chromosome 1-specific DNA probe, disomy for this chromosome was found in 0.67% of all accessible sperm cells.

Adult↗
PubMed1991

The effects of endotoxins on gametes and preimplantation embryos cultured in vitro.

Culture media used for human in-vitro fertilization (IVF) can be contaminated with bacterial endotoxins. All five tested types of commercially available albumin, sometimes used as a protein supplement to IVF media, were shown to contain endotoxins in varying concentrations. Endotoxins are suspected to cause embryo fragmentation and low pregnancy rates in human IVF. However, human sperm viability and the IVF of mouse oocytes and subsequent culture of the zygotes were shown to be unaffected by relatively high endotoxin concentrations. Therefore these techniques cannot be used as quality control assays to detect endotoxins in the IVF culture media.

Animals↗
PubMed1991

Evaluation of human sperm morphology using strict criteria after Diff-Quik staining: correlation of morphology with fertilization in vitro.

New, very strict criteria were used after Diff-Quik staining for evaluating sperm morphology. The results of morphology scoring were correlated with the fertilization rate in vitro. Semen samples from 64 men participating in an in-vitro fertilization programme were used for this study. All men had to have a sperm concentration of greater than or equal to 20 million/ml and a progressive motility of greater than 30%. The morphology evaluation using strict criteria was performed on the same aliquot of semen as that used for in-vitro insemination. If strict criteria showed that normal morphology was less than or equal to 4%, the fertilization rate per oocyte was 23%. If normal morphology was greater than or equal to 11%, 77% fertilization occurred. For proportions of normal morphology between 4 and 11%, the fertilization rate per oocyte was 59% (P less than 0.000001). Among all these morphology groups, classical semen parameters, such as the mean volume, the mean concentration and the mean motility, did not differ significantly, except for the morphology evaluation using WHO criteria. The correlation with fertilization was better for morphology evaluation using strict criteria than for WHO. In conclusion, the method of evaluating sperm morphology based on very strict criteria allows a more accurate prediction of the chance of fertilization in vitro. Further studies should be done to establish the most appropriate cut-off points for severely impaired, intermediate and high fertilization rates.

Azure Stains↗
PubMed1991

Immaturity and aneuploidy in human oocytes after different stimulation protocols.

OBJECTIVE: To study immaturity and aneuploidy in human oocytes after two different stimulation protocols. DESIGN: Retrospective. SETTING: Outpatient IVF clinic/laboratory. PATIENTS: One hundred forty-three patients of whom 65 were stimulated with clomiphene citrate (CC)/human menopausal gonadotropin (hMG) and 78 were stimulated with gonadotropin-releasing hormone agonist (GnRH-a)/hMG. Only patients with at least one oocyte unfertilized were included in this study. RESULTS: Stimulation with GnRH-a/hMG, as compared with CC/hMG stimulation, resulted in larger numbers of oocytes (P less than 0.00001), a higher fertilization rate (P less than 0.02), and oocyte retrieval at a later average cycle day (P less than 0.000005). Cytogenetic findings of immaturity were observed in 33.9% of unfertilized oocytes after CC/hMG stimulation, compared with only 17.8% after GnRH-a/hMG stimulation (P less than 0.0005). Aneuploidy findings were the same for both groups. CONCLUSION: In GnRH-a/hMG stimulation, oocytes approach the normal day of ovulation more closely. This may allow for better oocyte maturation and higher fertilization and pregnancy rates.

Aneuploidy↗
PubMed1990

[Phenylketonuria as a model system for DNA diagnosis of hereditary disorders].

Phenylketonuria (PKU), due to a defect in phenylalanine hydroxylase (PAH), is presented as a model system for computer-aided DNA diagnosis of genetic diseases. Eight different restriction fragment length polymorphism (RFLP) markers have been localized within the introns of the 90 kb PAH gene (located on chromosome 12). These RFLPs can be combined in 384 different ways and each combination has been defined as a particular haplotype. A special computer program has been developed to calculate the possible haplotype combinations in a PKU core family (index patient and parents), with the goal to derive unambiguously both the PAH and PKU alleles. Taking into account that participation of other members of the family (grandparents or brothers/sisters) is sometimes necessary, haplotyping by itself is sufficient to establish (or exclude) the PKU status of an individual in approximately eight out of ten PKU families.

Chromosomes, Human, Pair 12↗
PubMed1990

Rate of recombination of chromosomes 21 in parents of children with Down syndrome.

To test the hypothesis of reduced chiasma frequency causing nondisjunction during meiosis, we examined 34 Down syndrome patients and their parents. Chromosomal polymorphisms and RFLP markers were used to trace the parental origin as well as the frequency of recombination of chromosomes 21. In all but one case, the parental origin and the meiotic stage of nondisjunction could be established by either technique. In 11 cases recombination could be deduced to have taken place during meiosis in the parent who contributed the extra chromosome 21. Because of the underestimation which is inherent in the methods used, these results do not seem to support the chiasma theory.

Adult↗
PubMed1990

Human gametes and zygotes studied by nonradioactive in situ hybridization.

A nonradioactive in situ hybridization technique was applied to human gametes and abnormally fertilized or developed zygotes. Using haptenized chromosome-specific probes, visualization was obtained using immunocytochemistry to achieve a fluorescent stain on specific hybrids. Using a chromosome 1-specific DNA probe, almost all spermatozoa gave a positive result, i.e., one hybridization signal per cell could be observed. Furthermore, it was possible to identify sperm cells with two spots, suggesting nondisjunction. Two cleavage arrested embryos from different patients showed both: two brightly fluorescent spots and two weaker spots with the same DNA probe. Using a Y-specific DNA probe the percentages of positive spermatozoa from the normal males ranged between 48.1% and 49.1%. In an embryo with four grossly haploid chromosome sets, three fluorescent spots were obtained with the Y-specific DNA probe, indicating the penetration of three spermatozoa.

Antibodies, Monoclonal↗
PubMed1990

Human in vitro fertilization using spermatozoa capacitated in hyperosmotic media.

In two separate prospective randomized series of 38 and 16 attempts of human in vitro fertilization (IVF), respectively, the fertilizing abilities of human spermatozoa capacitated in hyperosmotic media and in normosmotic medium were compared. Oocytes from each IVF attempt were divided into two equal groups and inseminated with spermatozoa incubated for 2 h in medium with an osmolality of 285 mosm/kg or in hyperosmotic medium of 315 (first experiment) or 345 mosm/kg (second experiment). The fertilizing capacity of the spermatozoa was not affected by incubation in medium of 315 mosm/kg as compared to spermatozoa incubated in medium of 285 mosm/kg. However, the fertilizing capacity of the spermatozoa incubated in medium of 345 mosm/kg was significantly reduced. The present study indicates that there is no advantage in the use of hyperosmotic media of 315 or 345 mosm/kg for capacitation of spermatozoa in human IVF.

Culture Media↗