Biomedical subjects

L Pijpers

Publications and source records attributed to L Pijpers.

At least 19 recordsLinked to original sources

PubMed2004

[Two patients with a non-palpable, subcutaneously implanted contraceptive].

Two women, 33 and 31 years of age, were referred to a surgeon for the removal of a previously implanted hormonal contraceptive after the general practitioner had attempted this without success. However, no foreign body could be detected in either patient by surgery, echography and MRI and by X-ray, echography and MRI, respectively. They were then referred to a gynaecologist. In the first patient, a low level of etonogestrel confirmed that there was no contraceptive in her body. Subcutaneous contraceptives are sometimes implanted incorrectly. If the rod is not palpable at the site of insertion, then the etonogestrel level should be determined first of all. If the hormone level indicates that a rod is indeed present, then echography or MRI may be considered to localise it before resorting to surgical exploration. Many problems can be prevented by proper implantation.

Adult↗

PubMed2004

Potential intake of phytosterols/-stanols: results of a simulation study.

BACKGROUND: Different doses of phytosterols/-stanols up to a maximum of 4.0 g/day have been used in human safety studies, whereas only one small-scale study investigated some detailed clinical information about consumption levels exceeding 8.6 g/day. OBJECTIVE: To determine which population groups are likely to be at risk of excessive intakes if liberal enrichment of foods with phytosterols/-stanols will be allowed. DESIGN AND SUBJECTS: Cross-sectional study among a representative sample (n=23 106) of the Dutch population, aged 20-60 y (MORGEN-project, 1993-1997). Phytosterol/-stanol intake was assessed with virtual replacement of one to four ordinary foods in the diet with enriched products. Percentile values were used to describe the distribution in simulated intake for different groups in the population, varying in sociodemographic and health characteristics. Multiple linear regression was used to describe the contribution of the different population characteristics to the simulated phytosterol/-stanol intake. RESULTS: If three commonly consumed products (margarine, cheese, yoghurt) were completely replaced, the median daily phytosterol/-stanol intake will be about 5.5 g in men and 4.6 g in women. In males, the intake above the 90th percentile will exceed 8.6 g/day. Women will approach this level. Especially, age, body mass index, socioeconomic status, subjective health, smoking behaviour, alcohol consumption, pregnancy (women) and high cholesterol level (men) contributed to the variance in the simulated intake (P<0.05), although the total explained variance was low (1-3%). CONCLUSIONS: If liberal phytosterol/-stanol fortification is allowed, the daily intake might exceed the recommended intake level as well as our 'cutoff' level of 8.6 g/day. Postlaunch monitoring to identify consumers and real intake levels, refinement of scenario buiding, as well as human safety studies for levels above 8.6 g/day are necessary.

Adult↗

PubMed2001

The diagnostic performance of cytogenetic investigation in amniotic fluid cells and chorionic villi.

First-trimester chorionic villus sampling has not reached the popularity of second-trimester amniocentesis in prenatal cytogenetic diagnosis, in contrast to initial expectations. We investigated whether a difference in the diagnostic performances of cytogenetic investigation in amniotic fluid (AF) cells and chorionic villi in favour of AF-cells might justify this. Diagnostic performance was measured as laboratory failure rate, karyotype quality (G-band score, rate of follow-up samples, rate of wrong diagnoses), and karyotype representativity (rate of follow-up samples, rate of wrong diagnoses). From 1993-1999, 11 883 AF-samples were investigated (AF-cells). In chorionic villi, short term culture preparations solely were karyotyped from 1993-1996 (n=3499) (STC-villi), short and long-term culture preparations simultaneously provided a sufficient amount of tissue being available from 1997 onwards (n=1829) ((STC+LTC)-villi). Laboratory failure rates were the same after amniocentesis (0.40%) and chorionic villus sampling (0.50%). G-band scores (mean+/-SD) were equal in AF-cells (373+/-38.1) and LTC-villi (364+/-32.6) but significantly lower in STC-villi (311+/-34.6) (p=0.001). Follow-up sampling rates because of quality reasons were the same in AF-cells (0.14%), STC- villi (0.13%) and (STC+LTC)-villi (0.11%). Two wrong diagnoses turned up among AF-cells. Follow-up sampling rates because of representativity reasons differed significantly between AF-cells (0.10%), (STC+LTC)-villi (1.31%), and STC-villi (1.99%) (p<0.001). However, the ratios of the total numbers of follow-up samples and uncertain or abnormal cytogenetic results in STC, and (STC+LTC)-villi at cytogenetic risks > or =3% (0.132 and 0.160, respectively) were equal to that in AF-cells at risks <3% (0.155). Two wrong diagnoses were made in STC-villi. Diagnostic performance improved in the rank order of STC-villi, (STC+LTC)-villi and AF-cells. At cytogenetic risks > or =3%, (STC+LTC)-villi showed a diagnostic performance equal to that in AF-cells. This might justify a selective use of chorionic villus sampling.

Amniocentesis↗

PubMed2000

Accuracy of abnormal karyotypes after the analysis of both short- and long-term culture of chorionic villi.

We report in detail the cytogenetic results of 1838 consecutive chorionic villus samples with the availability of both short-term culture (STC-villi) and long-term culture (LTC-villi) preparations in 1561 cases (84.9%). A high degree of laboratory success (99.5%) and diagnostic accuracy (99.8%) was observed; in four cases of low mosaicism, all four associated with the final birth of a normal child, a small risk of uncertainty was accepted. The combined analysis of STC- and LTC-villi reduced follow-up amniocenteses by one-third in comparison with the analysis of STC-villi alone. We believe that the desired level of quality and accuracy of prenatal cytogenetics in chorionic villi can only be achieved when both STC- and LTC-villi are available. We conclude that CVS might then be the mode of prenatal diagnosis of first choice in pregnancies with a high (cytogenetic) risk.

Amniocentesis↗

PubMed1999

Prenatal detection of trisomy 18 caused by isochromosome 18p and 18q formation.

We report on the prenatal detection and further genetic studies in a case of trisomy 18 caused by isochromosome 18p [i(18p)] and 18q [i(18q)] formation. The diagnosis was made by standard cytogenetic techniques in amniotic fluid cells and confirmed by fluorescence in situ hybridization. The formation of the isochromosomes cannot be explained by a single model; centromere misdivision and meiosis II nondisjunction without recombination or mitotic misdivision are the most likely mechanisms of formation as indicated by DNA analysis.

Adult↗

PubMed1999

Amniocentesis or chorionic villus sampling in multiple gestations? Experience with 500 cases.

500 women with multiple pregnancies underwent amniocentesis or chorionic villus (CV) sampling at our department between January 1988 and July 1997. The aim of this retrospective study was to evaluate the laboratory aspects and the consequences of discordant results in these pregnancies in relation to the method of sampling. Uncertain results in one or both samples, requiring further investigation were more frequent in CV samples (eight times in 163 paired samples, 5 per cent) than in amniotic fluid (AF) samples (once in 298 paired samples, 0.3 per cent). Sampling one fetus twice (erroneous sampling) was seen only once among 163 pregnancies with two CV samples in our study. Cross contamination due to mixed sampling was discovered in two of seven pregnancies that underwent DNA diagnosis in CV and might be a rather regular occuring phenomenon. In none of the 500 pregnancies mixed sampling caused diagnostic dilemmas. A third sampling problem, maternal cell contamination caused a diagnostic problem once among the AF samples. Selective fetal reduction appeared safer after CV sampling than after amniocentesis. Subsequently, CV sampling instead of amniocentesis has become the method of choice for prenatal diagnosis in multiple pregnancies in our department.

Amniocentesis↗

PubMed1998

Abnormal karyotypes in semi-direct chorionic villus preparations of women with different cytogenetic risks.

Among 3499 cytogenetically investigated semi-direct chorionic villus samples, 219 (6.3 per cent) abnormal karyotypes were encountered. The karyotypes were considered certainly abnormal (generalized abnormal with high probability) in 109 cases (3.1 per cent), and in 110 cases (3.1 per cent) uncertainly abnormal (potentially confined to the placenta), requiring further investigation. Of these 110 uncertain abnormalities, the cytogenetic result turned out to be finally abnormal representing generalized abnormality in 36 cases (32.7 per cent), finally normal representing confined placental mosaicism (CPM) in 69 cases (62.7 per cent), and remained undetermined in 5 instances (4.5 per cent). The rate of the numbers of certainly abnormal and all (certainly + uncertainly) abnormal results, the certainty rate, and that of generalized abnormalities and all abnormalities (generalized abnormalities + CPM cases), the predictive value, are strongly correlated with the cytogenetic risk. Therefore, we advise chorionic villus sampling for cytogenetic investigation only in women with a cytogenetic risk equal to or exceeding that of a 40-year-old pregnant woman. Because of the high rate of prenatal follow-up investigations after the finding of uncertain results in semi-direct villi, semi-direct and cultured villi should be karyotyped simultaneously.

Adult↗

PubMed1995

Increased incidence of cytogenetic abnormalities in chorionic villus samples from pregnancies established by in vitro fertilization and embryo transfer (IVF-ET).

We studied 201 pregnancies that were established by in vitro fertilization and embryo transfer (IVF-ET) and compared the frequency of cytogenetic abnormalities with that found in a large control population matched for indication group (advanced maternal age) and time of sampling. A total of 252 IVF-ET fetuses were cytogenetically analysed by either chorionic villus sampling (CVS; n = 80) or amniocentesis (n = 172). Eleven chromosome abnormalities were found in the CVS group (13.8 per cent); among them, a 45,X/46,X,dic(Y)(q11)/46,X,del(Y)(q11) mosaic that was found in an IVF pregnancy established by intracytoplasmic sperm injection (ICSI), four cases of trisomy 21, and three cases of trisomy 7 confined to the placenta. The results indicate a statistically significant three- to five-fold increase in both confined placental abnormalities (P < 0.008) and true fetal chromosome anomalies (P < 0.04). In the amniocentesis group, identical rates (1.7 per cent) of chromosome abnormalities were found in the IVF-ET and control groups. It is concluded that late first trimester, but not early second trimester, IVF-ET pregnancies are characterized by an increased frequency of cytogenetic abnormalities found at prenatal diagnosis.

Adult↗

PubMed1992

The disposition of valproate and its metabolites in the late first trimester and early second trimester of pregnancy in maternal serum, urine, and amniotic fluid: effect of dose, co-medication, and the presence of spina bifida.

We have studied 52 pregnancies in epileptic women taking long-term valproate and have measured the concentrations of the parent compound and 13 of its metabolites by gas chromatography-mass spectrometry in amniotic fluid, maternal serum, and 24 h maternal urine samples. All metabolites of valproate present in the serum could also be detected in the amniotic fluid, although at much lower concentrations. Amniotic fluid concentrations of valproate and several of its metabolites ((E) delta 2-valproate, (2E,3'E) delta 2,3'-valproate, and 3-keto-valproate) correlated with total valproate concentrations as well as with unbound valproate concentrations in maternal serum. We suggest that the amniotic fluid acts as a deep compartment, with slow appearance and disappearance of valproate and its main metabolites. The data further suggest that during the first and early second trimesters of pregnancy the beta-oxidation of valproate decreases. In pregnancies associated with fetal neural tube defects (n = 5) significantly higher daily doses of valproate were used compared with normal pregnancies (n = 47). This resulted in higher concentrations of valproate in maternal serum. However, the metabolite patterns in maternal serum, 24 h urine samples, and amniotic fluid did not show any significant differences in pregnancies with neural tube defects.

Amniocentesis↗

PubMed1992

The risk of spina bifida aperta after first-trimester exposure to valproate in a prenatal cohort.

Use of antiepileptic drugs (AEDs) during pregnancy is associated with an increased risk of congenital malformations. Spina bifida aperta has been linked specifically to valproic acid (VPA) (estimated risk, 1 to 2%). The actual risk, the exclusive association of VPA with spina bifida and not anencephaly, and the precise causative relation remain matters of discussion. A prospective cohort study of pregnant women with epilepsy receiving AEDs and referred for prenatal diagnosis before week 22 of gestation was conducted, with follow-up to 3 months after birth. Pregnancies (291 singleton and 6 twin) in 261 women were evaluated. The prevalence of anomalies after exposure to any AED was 6.9%. For fetuses exposed to VPA, the prevalence was 9.4%, including six cases of spina bifida, two of which were in monozygotic twins (giving a prevalence rate of 6.3%, or 5.4%, if twins counted as one). Spina bifida was associated with a significantly higher average daily dose of VPA as compared with pregnancies with normal outcome (1.640 +/- 136 mg/d vs 941 +/- 48 mg/d, p = 0.0001). No relation was observed between the occurrence of spina bifida and type of maternal seizure or epilepsy, family history of epilepsy or neural-tube defects, or medical history. From these results we suggest that when the use of VPA during pregnancy cannot be avoided, the teratogenic risk might be diminished by reduction of the daily dose.

Adult↗

PubMed1990

Spontaneous abortion rate and advanced maternal age: consequences for prenatal diagnosis.

Maternal age related and procedure-related fetal abortion rates were studied in 384 women aged 36 and over scheduled for transabdominal chorionic villus sampling (TA-CVS) at 12-14 weeks of gestation. The pre-TA-CVS abortion rate within 30 days of intake (at 6-10 weeks of gestation) rose from 1.9% at age 35-36 years to 10.9% at 40 years and older. Women entering in the 6th week of gestation had a greater probability of aborting before TA-CVS than women entering after day 48. 26 women aborted spontaneously before TA-CVS, the majority of abortions occurring at 10-12 weeks. TA-CVS was done in 346 women. 11 pregnancies were terminated because of genetic anomalies, and 8 women had spontaneous fetal loss. These findings justify delaying prenatal diagnosis in older pregnant women until 12 weeks of gestation.

Abortion, Spontaneous↗

PubMed1990

Fetal loss rate after chorionic villus sampling and subsequent amniocentesis.

Here we review a group of 82 patients who underwent both chorionic villus sampling (CVS) and amniocentesis in the same pregnancy during the period May 1984-May 1988. A fetal loss rate of 2.5% is documented. This is not essentially different from the sum of fetal loss rates following each of the procedures separately (CVS, 1.9%; amniocentesis, 1.0%) established during the same period.

Amniocentesis↗

PubMed1990

Transabdominal chorionic villus sampling in a multiple pregnancy at risk of argininosuccinic aciduria: a case report.

We report on a 32-year-old G3P2 woman at increased risk of argininosuccinic aciduria in her offspring. In her first infant, the disease was diagnosed at age 3 months. In the second pregnancy, the disorder was excluded following incorporation of radio-labeled 14C-citrulline in intact chorionic villi obtained through transcervical chorionic villus sampling at 10 weeks gestation. Twins were diagnosed in the third pregnancy. Separate transabdominal chorionic villus sampling of both fetuses was carried out at 10 weeks gestation. Chromosome analysis demonstrated a normal male and female karyotype. Incorporation of radio-labeled 14C-citrulline in intact villi was deficient in both villus samples, establishing the diagnosis of argininosuccinic aciduria in both fetuses. The present results confirm the reliability of direct analysis of villi for the diagnosis of argininosuccinic aciduria.

Adult↗

PubMed1990

Interpretation of chromosome mosaicism and discrepancies in chorionic villi studies.

In 3,000 chorionic villi studies (CVS) 33 cases of mosaicism and 7 false-positive cell lines in all cells were seen. The mosaic cell lines were caused by aneuploidy of autosomes (13x), sex chromosomes (9x), and structural anomalies (11x). Mosaics of fetal origin were only 4 cases of trisomy 21 and one 47,XXY mosaic. In 7 cases abnormal karyotype of non-fetal origin was seen in all cells in direct studies, including trisomy 16 (3x) and trisomy 18 (2x). The combined use of direct CVS and cell cultures always uncovered the non-fetal origin of chromosome abnormalities and the study of cultured cells in all cases could have prevented 5 terminations. Complete follow-up studies demonstrated no false-negative results. Therefore, CVS can be nearly 100% accurate when both direct studies and cultures are examined in cases of mosaicism and other cell lines of possible non-fetal origin, such as trisomy 16, trisomy 18, translocation (21;21), and 45,X cells.

Aneuploidy↗

PubMed1990

Trisomy 21 mosaicism in gonads with unexpectedly high recurrence risks.

The recurrence risk for Down syndrome (DS) is about 1% in case of a previous offspring with trisomy 21 and minimal in case of a de novo (21;21) translocation. We have monitored 1,211 pregnancies in the first and second trimester after a prior occurrence of trisomy 21. Six couples had a trisomy 21 fetus in a subsequent pregnancy. We studied their lymphocytes, fibroblasts, and in one case ovaries, to detect parental mosaicism for chromosome 21. We detected mosaicism in 2 parents with 3 and 4 pregnancies, respectively, in which trisomy 21 was found. In one it was present in 47% of cells from the ovaries. Another couple with a pregnancy monitored because of a first child with a de novo (21;21) translocation had normal chromosomes themselves and one normal child, but 2 more pregnancies with a (21;21) translocation. It is concluded that thorough cytogenetic study of parents is indicated after 2 pregnancies with regular or translocation trisomy of chromosome 21. Genetic counseling should consider the possibility of an elevated recurrence risk due to gonadal mosaicism in one parent.

Adult↗

PubMed1990

Transabdominal villus sampling in early second trimester: a safe sampling method for women of advanced age.

Transabdominal chorionic villus sampling (TA-CVS) was performed in 707 viable singleton pregnancies to exclude chromosomal abnormalities. Maternal age ranged between 36 and 49 years (mean 37.9 years); gestational age varied between 10.2 and 18.3 weeks (mean 13.3 weeks). In 639 women (90.4 per cent), a sufficient amount of chorionic tissue (greater than or equal to 10 mg) was obtained after one needle insertion; in 66 women (9.3 per cent) two insertions were needed. An abnormal chromosome pattern was established in 19 cases (2.9 per cent). Vaginal bleeding or spotting within 28 days after TA-CVS occurred in 11 cases (1.5 per cent). The completed follow-up of 678 chromosomally normal pregnancies showed an overall fetal loss rate of 2.6 per cent before 28 weeks. The overall perinatal mortality was 0.9 per cent. When relating fetal loss to gestational age at TA-CVS, this was 6.6 per cent in women sampled before 12 weeks against only 1.8 per cent after 12 weeks. At the same time, the percentage of fetal loss occurring within 2 weeks following the procedure was 75 and 30 per cent, respectively. It is suggested that these data reflect the decline in spontaneous abortion rate during this particular period of pregnancy. It is concluded that TA-CVS is an effective procedure which, when performed after the natural decrease of fetal loss, appears to be a safe option for women of advanced maternal age.

Abdomen↗

PubMed1990

Leiomyoma of the ovary.

Ovarian leiomyoma is a rarity. Usually it is not associated with any clinical symptoms. Macro- and microscopically it is indistinguishable from the uterine leiomyoma. Treatment consists of simple removal of the tumor. The possible histogenesis of this tumor is reviewed. It is concluded that the ovarian leiomyoma probably originates from the smooth muscle cells of the ovarian blood vessel or from the smooth muscle fibers near the attachment of the ovarian ligament.

Adult↗

PubMed1989

Rhesus sensitization after midtrimester genetic amniocentesis.

In 944 Rh-negative patients who received rhesus immunoglobulin (anti-D) following genetic amniocentesis, not a single case of Rh sensitization occurred. Routine administration of a small dose (100 micrograms) of anti-D is effective in preventing Rh sensitization after midtrimester amniocentesis.

Amniocentesis↗