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Biomedical subjects

B T de Wolf

Publications and source records attributed to B T de Wolf.

16 recordsLinked to original sources
PubMed2001

Anatomical and functional changes in the lower urinary tract during pregnancy.

OBJECTIVE: To assess the prevalence and the development of urinary incontinence in nulliparous pregnant women, both subjectively and objectively, and to investigate the relation of incontinence with the mobility of the urethro-vesical junction measured by perineal ultrasound. DESIGN: A prospective longitudinal study. SETTING: University Hospital and Martini Hospital Groningen, the Netherlands. POPULATION: A cohort of 117 nulliparous pregnant women and 27 nulliparous non-pregnant controls. METHODS: Urinary incontinence was measured by a questionnaire and by a 24-hour pad test. The position of the urethro-vesical junction and its mobility were measured by perineal ultrasound. MAIN OUTCOME MEASURE: Prevalence of urinary incontinence; mobility of the urethro-vesical junction, indicated by the displacement/pressure coefficient. RESULTS: Up to 35% of the women reported urinary incontinence in pregnancy, and 20% of the women had a positive pad test. The angle of the urethro-vesical junction angle at rest and the displacement/pressure coefficient during coughing showed a significant increasing trend during pregnancy, but no changes were seen during the Valsalva manoeuvre. No relationship was found between subjective and objective incontinence data and the position and mobility of the urethro-vesical junction. CONCLUSION: The prevalence of incontinence in nulliparous women as found by the pad test was significantly higher in pregnancy (20%) than in the non-pregnant control group (4%). Perineal ultrasound of the urethrovesical junction showed lowering of the pelvic floor occurring as early as 12-16 weeks of pregnancy. Serial measurements of the displacement/pressure coefficient suggest that the dynamic characteristics of the connective tissues of the pelvic floor remain unaltered,whereas a significant decrease in pelvic floor muscle contraction occurs. Since no relation was found between measurements of the urethro-vesical junction and incontinence, urinary incontinence in pregnancy is most likely explained by other factors.

Adolescent↗
PubMed2001

First-trimester maternal serum human thyroid-stimulating hormone in chromosomally normal and Down syndrome pregnancies.

Maternal serum human thyroid-stimulating hormone (TSH) levels were investigated in chromosomally normal and Down syndrome pregnancies to determine whether TSH can be used as a marker for Down syndrome in the first trimester. Measurements were conducted on stored serum samples collected from 23 Down syndrome pregnancies and 115 unaffected pregnancies before chorionic villus sampling (CVS), between 9 and 11 completed weeks of pregnancy. The samples were matched for gestational age, maternal age, maternal weight and duration of storage of the serum sample. Maternal TSH concentration was slightly decreased in Down syndrome pregnancies, with a median of 0.84 multiples of the median (MoM). Maternal serum human chorionic gonadotropin (hCG) concentration was slightly elevated in Down syndrome pregnancies, with a median of 1.03 MoM. Both differences were not significant applying matched rank analysis (p=0.50 for TSH and p=0.43 for hCG). The association between TSH and hCG in unaffected pregnancies was also measured. The Spearman correlation coefficient between TSH and hCG was -0.21 which was statistically significant (p=0.02, 95% confidence interval -0.38 to -0.03). However, it was concluded that TSH is not a useful marker for distinguishing Down syndrome-affected pregnancies from normal pregnancies in the first trimester.

Adult↗
PubMed1998

Maternal serum levels of free beta-hCG and PAPP-A in the first trimester of pregnancy are not associated with subsequent fetal growth retardation or preterm delivery.

The purpose of this case-control study was to examine the association of first-trimester concentrations of free beta-human chorionic gonadotropin (free beta-hCG) and pregnancy-associated plasma protein A (PAPP-A) in maternal serum with subsequent preterm delivery or small-for-gestational age (SGA) fetuses. We collected all the blood samples before chorionic villus sampling in the first trimester. Concentrations of free beta-hCG and PAPP-A were expressed in multiples of the median (MOM) for gestational age. We compared the levels of both analytes in 73 SGA pregnancies (birth weight below the fifth percentile) with those in 292 normal controls, who were matched for gestational age, maternal age, parity, maternal weight, and smoking habits. We also compared the levels in 87 pregnancies with a preterm delivery (delivery before 37 completed weeks) with those in 348 matched controls. The median concentrations of PAPP-A and free beta-hCG, expressed in MOMs, in the 73 SGA pregnancies were 0.83 and 0.95, respectively, compared with 0.98 and 1.01, respectively, in the 292 matched controls (P=0.08 and 0.19, respectively). In the 87 pregnancies with a preterm delivery, the median concentrations of PAPP-A and free beta-hCG were 0.98 and 0.94, respectively, compared with 0.99 and 0.99, respectively, in the 348 matched controls (P=0.82 and 0.10, respectively). In contrast with the maternal serum analytes used in second-trimester screening--alpha-fetoprotein and human chorionic gonadotropin--this study showed that concentrations of PAPP-A and free beta-hCG in the first trimester were not associated with subsequent fetal growth retardation or preterm delivery.

Adult↗
PubMed1997

A demographic approach to the assessment of Down syndrome screening performance.

The aim of this article is to examine the performance of screening for fetal Down syndrome (DS) in the context of demographic variation in time and place, using population and fertility data for several European countries. Two screening approaches are distinguished: one on the basis of maternal serum screening with human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP) in combination with maternal age, and one on the basis of maternal age only. Screening performance, as measured by detection and false-positive ratios, is shown to be the result of the screening approach chosen and of the demographic characteristics of the population under consideration. A proper distinction between these two determinants of DS screening performance should be made, in order to distinguish between an improvement in screening performance that is brought about by a new screening approach and an improvement that is brought about by demographic change. We recommend that measures of DS screening performance be standardized for demographic variation. The methodology and demographic data presented in this article can be used for this purpose.

Adolescent↗
PubMed1996

The relation between serum markers in the second trimester and placental pathology. A study on extremely small for gestational age fetuses.

OBJECTIVES: To examine whether in women who are delivered of an extremely small for gestational age infant, raised levels of second trimester maternal serum alpha-fetoprotein (MSAFP) or human chorionic gonadotrophin (MShCG) levels are related to the presence of placental pathology detected at birth. DESIGN: Retrospective cross-sectional study. SETTING: Department of Obstetrics and Gynaecology, Antenatal Diagnosis Unit, Groningen University Hospital, The Netherlands. PARTICIPANTS: Eighty-four women who were delivered of an extremely SGA infant (< 2.3rd centile) in whom the MSAFP and the MShCG levels were known and placental pathology reports were available (study group), and 8692 women in whom the MSAFP and MShCG levels were known and the pregnancy outcome was normal (control group). Pregnancies with congenital anomalies were excluded. Analyte levels were expressed in multiples of the median (MoM) for gestational age. Statistical analysis between groups was performed by ANOVA, after logarithmic transformation of the MoMs, to normalise their distribution. MAIN OUTCOME MEASURES: 1. The means of the MSAFP and MShCG concentrations in the study group with and without placental lesions were compared with those in the control population. 2. The means of the MSAFP and MShCG levels in the study group with placental lesions were compared with those in the study group without placental lesions. RESULTS: 1. Comparison of study groups with controls: in the study group without placental lesions, the mean log MSAFP MoM (0.062), as well as the mean log MShCG MoM (-0.033), was not significantly different (P = 0.11 and P = 0.68, respectively) from the mean analyte levels in the control population (0.002 and 0.006, respectively). The mean logs of these analytes in the study group with placental lesions (0.162 and 0.129, respectively) were significantly higher compared with the MSAFP and MShCG levels in the control population (P < 0.001 for both analytes). 2. Comparison of study groups with each other: the mean log of the MSAFP level of 0.162 in the group with placental lesions was significantly different from the mean of 0.062 of the study group without placental lesions (P < 0.025). The higher mean log MShCG MoM of 0.129 in the group with placental lesions was significantly different from the mean log MShCG MoM of -0.033 in the study group without placental lesions (P < 0.025). CONCLUSIONS: Raised levels of second trimester MSAFP and MShCG in women who are subsequently delivered of an extremely small for gestational age infant are related to the presence of pathological changes in the placenta, detectable at birth. It is speculated that these placental pathological changes, which frequently accompany small for gestational age pregnancies, have their origin in the second trimester, when the normal physiological changes of the placenta occur.

Analysis of Variance↗
PubMed1995

Evaluation of a computer-aided semen analysis system with sperm tail detection.

The aim of this study was to evaluate the Stroemberg-Mika cell motion analyser (SM-CMA) which uses tail detection in order to discriminate between immotile spermatozoa and other particles. Analysis of the spermatozoa by the SM-CMA can easily be checked on a video monitor. The semen samples were from donors and patients visiting the fertility unit of the University Hospital, Hanzeplein, The Netherlands. Both fresh semen samples and purified sperm suspensions were used to estimate sperm counts and motility characteristics. We tested the use of the x10 objective instead of the x20 and we assessed the ways in which motility characteristics were influenced by temperature. We found a considerable discrepancy between sperm concentrations measured manually and by computerized analysis, both in semen samples and in purified sperm suspensions. The SM-CMA correctly recognizes motile spermatozoa, but underestimates immotile ones. Although temperature affects motility characteristics, in routine measurements the influence of short cooling periods, which are unavoidable, was nil. We found that using the x10 objective can be useful, especially at low sperm concentrations. In our opinion, the SM-CMA system is, despite some shortcomings in its user-interface, a useful and versatile instrument for examination of human semen samples, with desirable features.

Evaluation Studies as Topic↗
PubMed1995

Variability of continuously measured arterial pH and blood gas values in the near term fetal lamb.

In fetal sheep, arterial blood gas values show considerable spontaneous fluctuations. The aim of the present study was to obtain quantitative data on fetal blood gas variability. Accurate assessment of the intraindividual variations can hardly be obtained from intermittent blood samples, but requires continuous measurement. For this purpose we developed a small extracorporeal flow-through cuvette, containing pH and blood gas electrodes and the fiber optic probe of an oximeter. The cuvette is connected through two catheters to the fetal circulation. Blood from the carotid artery flows through the cuvette at a constant rate of 2 mL/min and is drained into the jugular vein. Continuous recordings for 6 h were obtained from five chronically instrumented sheep fetuses at 134-137-d gestational age. Intraindividual variability of fetal arterial blood pH (pHa), partial pressure of arterial blood CO2 (Paco2) and O2 (Pao2), and saturation of arterial blood (Sao2) is quantitatively described. The individual variation coefficients ranged from 0.1 to 0.4% (pHa), from 1.4 to 7.6% (Paco2), from 2.5 to 5.5% (Pao2), and from 3.6 to 7.0% (Sao2). The 5th to 95 percentile intervals (delta) of the individual blood gas values ranged from 0.03 to 0.09 (pHa), from 0.3 to 1.6 kPa (Paco2), from 0.22 to 0.5 kPa (Pao2), and from 10.5 to 26.0% (Sao2). These findings indicate that considerable fluctuations in fetal arterial blood gases occur during a 6-h period. These fluctuations are associated with uterine contractures and changes in maternal and fetal activity.

Analysis of Variance↗
PubMed1993

[Serum screening of pregnant women for fetal neural tube defects and Down syndrome; initial experiences in The Netherlands].

OBJECTIVE: To examine if, and if so, in what way, the maternal serum screening for fetal neural tube defects (NTD) and Down's syndrome (DS) in the Dutch decentralized obstetrical organization would be feasible and effective. DESIGN: Prospective. SETTING: University Hospital Groningen. METHOD: Between October 1st 1990 and December 1st 1991 we determined the likelihood of a baby with a NTD and/or DS in 2580 pregnant women, at 15 to 20 weeks gestation, by serum screening. RESULTS: Five foetuses with DS were detected, as well as two with a NTD, one foetus with an omphalocele, and one with Turner's syndrome. One infant with a NTD and one with DS were not found prenatally. Of all 98 women of 36 years or older, 68 declined amniocentesis because their risk was lower than the age related risk. CONCLUSIONS: Maternal serum screening for NTD and DS is feasible and effective in principle. In a decentralized prenatal care system, special attention has to be paid to the time needed to report the results and to the completion of the follow-up. The detection rate of DS in pregnant women of 36 years or older remains almost the same, but a significant number of them decline prenatal diagnosis. An increased risk of foetal DS, determined by serum screening, should be added to the official list of indications for prenatal diagnosis in the Netherlands.

Adolescent↗
PubMed1990

Nuchal muscle activity at different levels of hypoxemia in fetal sheep.

The effects of hypoxemia on nuchal muscle activity, a parameter of gross body movements, were studied during 12 experiments in five chronically instrumented fetal lambs. Hypoxemia was accomplished by tracheal infusion of nitrogen and did not result in significant changes in fetal arterial pH and PCO2. Fetal arterial blood gases and pH were continuously measured with an extracorporeal flow-through cuvette. Nuchal muscle activity was measured by electromyography and was expressed as the percentage of time spent moving. A decrease in fetal arterial oxygen saturation to three fourths of the initial value for 2 hours was not associated with significant changes in nuchal muscle activity. When fetal arterial oxygen saturation was further reduced for 2 hours to one half, fetal nuchal muscle activity fell significantly from 34.6% +/- 10.5% during normoxemia to 20.9% +/- 13.9% during hypoxemia. However, the most pronounced changes in fetal nuchal muscle activity occurred in the first 15 minutes after the changes in arterial oxygen saturation. A considerable transient increase in nuchal muscle activity was observed during the first 15 minutes after recovery from hypoxemia. During hypoxemia there was a relative predominance of short-lasting (less than 3 minute) movements.

Animals↗
PubMed1979

Raised maternal serum-alpha-fetoprotein levels and spontaneous fetomaternal transfusion.

Study of blood smears showed that spontaneous fetomaternal transfusions were significantly more common among 42 pregnant women with raised serum-alpha-fetoprotein (AFP) levels than among 45 pregnant women with normal serum-AFP levels. Raised serum-AFP was associated with a spontaneous fetomaternal transfusion of greater than or equal to 0.1 ml in at least 21 of the 42 women in the study group.

Amniocentesis↗
PubMedDate not supplied

Variation in semen parameters derived from computer-aided semen analysis, within donors and between donors.

The development of computer-aided semen analysis (CASA) has made it possible to study sperm motility characteristics objectively and longitudinally. In this 2-year study of 8 sperm donors, we used CASA to measure 7 semen parameters (concentration, percentage of motile spermatozoa, curvilinear velocity, average path velocity, straight-line velocity, amplitude of lateral head displacement, and beat/cross frequency). The frequency distributions of the 7 parameters in the semen samples of each donor were investigated. All parameters but one were normally distributed; concentration was distributed log-normally. Variation within individual donors and between donors was studied. Analysis of variance demonstrated that variation between donors was not explained by the longitudinal variation within individual donors. Variations in motility characteristics between donors were substantial, which may make motility characteristics of limited value as a tool for establishing fertility. Strong correlations were found between the 7 parameters, partly because by definition, motility characteristics are interdependent. Fisher's discriminant analysis demonstrated that each donor appeared to have his own set of semen characteristics and, more specifically, his own motility signature. From this data set it can be predicted that in order to find population means among sperm, it may be more efficient to measure more subjects than to increase the number of samples per subject.

Humans↗