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Biomedical subjects

M Vekemans

Publications and source records attributed to M Vekemans.

At least 181 records · Page 10Linked to original sources
PubMed1990

[A psychological study, using interviews and projective tests, of patients seeking anonymous donor artificial insemination].

A Thematic Aperception Test was used with 13 male and 16 female patients who were requesting A.I.D. The following main psychological reactions were found in women: anxiety and depression (fear of rejection by their family and friends; lowering the image of the husband--the donor being considered as a rival), aggression (the narcissistic woman "demands" A.I.D.; the donor is esteemed highly); mother is protective ("true" paternity comes through love of the child and the need to forget the donor). They found, in men: an inability to abandon fertility as lost (with denial of sterility); ambivalence, castration anxiety and a feeling of being excluded from the mother-child symbiosis with later acceptance of loss of fertility and (sometimes excessively) identification with the "mother". Most subjects studied were not intending telling the child about his true origin; because disclosure would be tantamount to transgressing twice over the laws of paternity and the rules against Oedipus behaviour. There is often a great difference between the ways the partners view the matter and inter-relate. We strongly recommend that psychological advice should be taken before treatment with A.I.D. is started.

Aggression↗
PubMed1989

A presumptive translocation 1p;2q resulting in duplication 1p and deletion 2q.

Here we report on a girl with a translocation between 1 and 2 and duplication 1p and deletion 2q resulting in a multiple congenital anomaly syndrome including intrauterine growth retardation, microcephaly, hypotelorism, cleft palate, subglottic stenosis, umbilical hernia, scoliosis, anal atresia, bilateral calcaneovalgus, overlapping toes, and vertebral anomalies.

Abnormalities, Multiple↗
PubMed1989

Is fresh or frozen semen to be used in in vitro fertilization with donor sperm?

Sixty-six partners of either severely oligoasthenospermic or azoospermic men were treated by in vitro fertilization with donor sperm (IVF-D), usually (86%) after failure of artificial insemination with donor sperm. One hundred twenty-nine IVF trials were performed with either fresh (59%) or frozen-thawed (41%) donor sperm. Characteristics of sperm preparations were significantly lower in the frozen-thawed group (P less than 0.001). In the latter group, fertilization rates had slightly decreased (but without statistical significance); embryonic vitality scores and cryopreservable spare embryos had significantly decreased (P less than 0.05). However, cumulative ongoing pregnancy rates were strictly equivalent in both groups (40% after three trials). Frozen-thawed sperm thus can be substituted for fresh donor sperm without entailing impairment of the outcome of IVF, and this method must be preferred for its greater safety regarding transmission of human immunodeficiency virus.

Female↗
PubMed1989

Cytogenetic analysis of Wilms' tumor: evidence of a multistep process.

We report the cytogenetic findings observed in the cancer cells of a Wilms' tumor in a 11-month-old girl without the phenotype of the WAGR. Two populations were identified: one had a 46,XX,del(11)(p11p13) karyotype and the other had a translocation involving the deleted chromosome 11 and chromosome 12, t(11;12)(p11;q13). This result strongly suggests that the deletion of 11p was the initiating event to the tumor and that the translocation has been instrumental in promoting its development.

Chromosome Aberrations↗
PubMed1989

[Should one use fresh or frozen sperm in in-vitro fertilization with donors?].

Between 1984 and 1987, 66 women whose partner had severe oligo-asthenoteratospermia or azoospermia underwent in vitro fertilization (IVF) with donor sperm. The mean duration of sterility was 7.5 +/- 3.2 years. Investigations performed in the women showed no abnormality in 30%, pure endocrinopathies in 21% or tubal diseases isolated or associated with other pathologies in 40%. Most of these women (86%) had had previous unsuccessful inseminations with donor sperm. Our study involves 129 attempts of IVF with donor sperm (1 to 3 attempts per patient); the sperm was fresh in 59% of the cases and cryopreserved in 41%. Initial and final motility and sperm density are significantly lower for cryopreserved sperm (p less than 0.001). The fertilization rate is lower with cryo-preserved sperm but the difference is not statistically significant. Moreover, the score of embryonal vitality and the number of embryos that can be cryopreserved are lower with cryopreserved sperm (p +/- 0.05). However the number of pregnancies is identical with one or another type of sperm (40% of the women after 3 IVF). To conclude, cryopreserved sperm may be used for IVF without lowering the percentage of success. In fact, the fertilization rate, the embryonal score and the number of embryos to deep freeze are slightly less with cryopreserved sperm and this difference could reveal to be significant with a larger cohort of patients. But the advantage of fresh sperm must be balanced by the risk of AIDS contamination, avoided with cryopreserved sperm.

Acquired Immunodeficiency Syndrome↗
PubMed1989

An investigation of factors influencing the survival of trisomic fetuses in the mouse.

The prevalence of trisomy at a given time of gestation depends on two factors: its incidence at conception and the probability that the trisomic embryo or fetus survives up to the time of observation. In mammals, little is known about the factors controlling either of these two events. A mouse model is particularly useful for these types of studies, as it allows us to examine each event, under strictly controlled experimental conditions. Using this mouse model, a systematic analysis of the influence of various factors including maternal age, diet, as well as fetal and maternal genes, on the survival of trisomic fetuses, at different times of gestation, has been performed. Our studies show that high post-implantation survival of trisomic fetuses is associated with a specific diet or a specific maternal gene, but not increasing maternal age. Future studies are aimed at identifying the specific genetic and environmental factors involved, and understanding their pathogenesis.

Animals↗
PubMed1988

Early pregnancy loss and obstetrical risk after in-vitro fertilization and embryo replacement.

Between March 1983 and March 1986, 108 pregnancies were obtained at the IVF clinic of St Pierre Hospital in Brussels. There were 29 chemical pregnancies (26.8%), five ectopic pregnancies (4.6%), 15 abortions (14%) and 59 ongoing pregnancies of over 20 weeks (54%). Patients who had experienced a chemical pregnancy at first trial displayed a significantly higher rate of ongoing pregnancy at their second attempt. Among the 15 cases of abortion, a chromosomal anomaly was detected in two cases and suspected in a third. Four of the five ectopic pregnancies occurred in patients with previously documented tubal pathology. The ongoing pregnancies were distributed as 44 singletons, 13 pairs of twins, one set of triplets and one set of quadruplets. The Caesarian section rates were 21 and 40% for single and multiple pregnancies, respectively. The prematurity rate was low for singletons (4.5%) but reached 46.6% in multiple pregnancies. Two minor malformations were observed and five perinatal deaths occurred; among these latter, four cases were twins. It appears that perinatal pathology is substantially higher among IVF pregnancies than in the normal population. It is clear, however, that most of this difference is accounted for by the considerably higher rate of twin pregnancy displayed by the former group.

Abortion, Spontaneous↗
PubMed1987

Animal model: genetic control of the survival of trisomic fetuses in mice: a preliminary report.

Using trisomy 19 produced experimentally in mice, we examined the genetic control of the survival of trisomic fetuses. Data are presented that show clearly that the prevalence of experimentally produced trisomy 19 in mice, observed on day 15 of gestation, is genetically influenced. There appeared to be an inverse relationship between strain differences in frequency of trisomy 19 fetuses and frequency of fetal loss, suggesting that the observed differences in prevalence of trisomy 19 fetuses resulted from differential survival of trisomic fetuses.

Animals↗
PubMed1987

Effect of aneuploidy and neoplasia on human ribosomal DNA inheritance.

A DNA length polymorphism in the nontranscribed spacer region of the repeating unit that codes for human ribosomal RNA produces a characteristic pattern or restriction fragments in each individual. Quantitative densitometric analysis of ribosomal ribosomal DNA fragment distribution in families demonstrates additive inheritance in those with chromosomally normal or aneuploid offspring. Differences between offspring and parental ribosomal DNA patterns could be explained by a heterogeneous distribution of length variants on the acrocentric chromosomes. New ribosomal DNA length variants of 9.0, 6.7, 5.5, and 5.2 kilobases were observed in normal individuals after BamHI restriction, and the former two were present in multiple copies. A panel of solid tumor specimens exhibited ribosomal DNA patterns that were generally characteristic of the patient rather than tumor type. However, novel ribosomal DNA length variants or changes in length variant proportions were noted in three of the four tumors for which adjacent normal tissue was available for comparison; these alterations occurred in a Burkitt lymphoma, a teratoma, and a Wilms tumor. A consistent karyotype of 50,XY in the Wilms tumor specimen supports previous evidence for increased repetitive DNA variation in aneuploid, neoplastic tissues.

Aneuploidy↗
PubMed1987

Higher pregnancy rates after in vitro fertilization and embryo transfer in cases with sperm defects.

One hundred thirty-three couples were classified into four groups according to previous sperm analyses. These couples underwent 237 in vitro fertilization trials that led to 46 clinical pregnancies (19.4%/trial). Clinical pregnancy rate per laparoscopy of the group with male defects was significantly higher than that of the normospermic couples (25 versus 14%, P less than 0.05). The fertilization rate was significantly reduced only if two sperm anomalies were present (P less than 0.05). However, the mean number of embryos transferred did not differ significantly among the four groups, but the proportion of trials without transfer was increased with regard to the severity of sperm defect. Implantation rate per embryo in cases of triple transfer was significantly higher in the group with sperm anomalies as compared with the normospermic cases (18 versus 10%, P less than 0.02). Correction of the male problem through IVF treatment allows higher female fertility to be disclosed in these cases.

Adult↗
PubMed1987

In-vitro fertilization with donor sperm after failure of artificial insemination.

This retrospective study compares results of artificial insemination by donor (AID) and in-vitro fertilization (IVF) trials, and especially of IVF treatment with fresh donor spermatozoa in patients who were unsuccessfully treated on 18 occasions by AID using frozen semen. AID gives cumulative pregnancy rate of 54.6% after six trials. But after 18 trials, 22.4% of the patients were still not pregnant. Treating them with IVF gave a probability of pregnancy as good as in the other IVF patients, 53.9% after six trials. However, pregnancy loss rates differed resulting in cumulative normal pregnancy rates of 16.2% in AID cycles ranking from 19 to 24 compared with 41.8% when going to IVF. In 'ex-AID' women, significantly more follicles were punctured, but the number of oocytes obtained and fertilized, embryos replaced, and the incidence of pregnancy did not differ from the other patients. Considering separately the various infertility factors encountered in the patients, the pregnancy rates still did not differ between ex-AID women and the others. Changing from long-term failed AID to IVF is certainly acceptable and even more so with the newly introduced technique of trans-vaginal puncture. The female infertility factors involved in AID failure are corrected in IVF.

Adult↗
PubMed1987

Specific 1,25-hydroxycholecalciferol receptors and stimulation of 25-hydroxycholecalciferol-24R hydroxylase in human amniotic cells.

We have analyzed the 1 alpha, 25-dihydroxycholecalciferol [1,25(OH)2D3] receptor content of cultured cells from human amniotic fluid. Six cell lines were grown to confluence in a minimum essential medium containing 20% fetal calf serum. All had a normal karyotype, five were male and one was female. Hypertonic cytosol extracts were prepared by sonication followed by centrifugation at 200,000 X g 30 min. Saturation analysis was performed by incubating the extracts with [3H]-1,25(OH)2D3 (20-500 pM, 160 Ci/mmol) with and without 100-fold molar excess of unlabeled 1,25(OH)2D3. Linear sucrose gradient (5-20% w/v) analysis was performed with 1.5 nM [3H]-1,25(OH)2D3 alone or in presence of 100-fold molar excess, 1,25(OH)2D3. Functional responsiveness was measured by induction of 25-hydroxycholecalciferol-24R-hydroxylase with 1 and 10 nM 1,25(OH)2D3. The six cell lines studied had receptors with dissociation constant of 44 +/- 6 pM (mean +/- SEM). The binding capacity was 10,200 +/- 1,750 sites/ng protein (mean +/- SEM) with extreme values of 4,700 and 15,500. A single peak for specific binding migrating at approximately 3S was observed by sucrose gradient centrifugation. 25-Hydroxycholecalciferol-24R-hydroxylase was induced by 1 and 10 nM 1,25(OH)2D3 in a dose-dependent fashion. The data show that receptors for 1,25(OH)2D3 are present in cultured amniotic fibroblast-like cells early in pregnancy. These cells may thus prove to be useful for further characterization of 1,25(OH)2D3 receptors in fetal tissue.

Amniotic Fluid↗
PubMed1986

Diagnosis of chromosome 3 duplication q23----qter, deletion p25----pter in a patient with the C (trigonocephaly) syndrome.

The cells of a deceased patient previously reported to have the C (trigonocephaly) syndrome were reinvestigated because his phenotype resembled that of a patient with a duplication-deficiency of chromosome 3. This diagnosis was confirmed using fibroblasts grown from frozen cells, and his mother was shown to carry an inversion of chromosome 3 in her peripheral blood leukocytes. His findings are compared to those of another patient with the C trigonocephaly syndrome with normal chromosomes and to others from the literature. At least one other patient from the literature has a phenotype compatible with "3q duplication syndrome."

Abnormalities, Multiple↗