Biomedical subjects

P F Boekkooi

Publications and source records attributed to P F Boekkooi.

14 recordsLinked to original sources

PubMed2001

[Embolization as treatment for symptomatic uterus myomata].

Selective percutaneous embolisation of the uterine arteries was carried out on three women with hypermenorrhea caused by uterine myomata. Two of the patients experienced resumption of the normal menstrual pattern. In the first case the myoma became 30% smaller and in the second case, the fibroid was expelled into the vagina six months later. The third patient suffered a fever one week after the treatment due to an infected necrotic myoma, after which a hysterectomy was carried out. The embolisation of myomata can offer an alternative to medicinal treatment, myomectomy or hysterectomy. The advantages of embolisation compared to a hysterectomy are a shorter hospital admission time, quick recovery after the procedure and retention of the uterus.

Adult↗

PubMed2001

Fetal habituation to vibroacoustic stimulation in uncomplicated postterm pregnancies.

OBJECTIVES: Testing of fetal habituation to repeated vibroacoustic stimulation might give additional information concerning the fetal condition and central nervous system (CNS) functioning in postterm pregnancies. This study is designed to investigate whether healthy postterm fetuses are able to habituate and if so, if the habituation pattern of postterm fetuses differs from that of term fetuses. STUDY DESIGN: Twenty women with an uncomplicated pregnancy beyond 41 weeks gestational age (GA) participated, and 37 women with a GA between 37 and 40 weeks served as controls. The vibroacoustic stimulus was repeatedly applied to the maternal abdomen above the fetal legs for a period of 1s every 30s. A fetal trunk movement within 1s of stimulus application was considered a positive response. Lack of response to four consecutive stimuli indicated habituation. The habituation rate is defined as the number of stimuli applied before the fetus stopped responding. Data were compared using Mann-Whitney U test. RESULTS: Of the 18 postterm fetuses in which the presence or absence of habituation could be established, 14 habituated and four persisted in responding. Twenty-six of the 32 term fetuses, in which the presence or absence of habituation could be established, habituated and six persisted in responding. The habituation rate varied widely in postterm (median of eight stimuli, quartile ranges of 6 and 18) as well as in term fetuses (median of 9.5 stimuli, quartile ranges of 6 and 15). There was no difference in median habituation rate between postterm and term fetuses. CONCLUSION: The ongoing maturation of the CNS in the last weeks of pregnancy appears not to be reflected in the fetal habituation pattern. Furthermore, the interfetal variability in habituation of healthy postterm fetuses is such that testing of habituation appears not to be suitable for the identification of the fetus at risk for an adverse neonatal outcome.

Acoustic Stimulation↗

PubMed2001

Fetal habituation to vibroacoustic stimulation in relation to fetal states and fetal heart rate parameters.

OBJECTIVES: Fetal habituation to repeated stimulation has the potential to become a tool in the assessment of fetal condition and of the function of the fetal central nervous system (CNS). However, the influence of fetal quiescence and activity on habituation remains to be clarified. We studied habituation and the influence of fetal state and fetal heart rate (FHR) parameters on habituation in healthy term fetuses. SUBJECTS AND METHOD: We studied habituation in 37 healthy fetuses in two tests with an interval of 10 min. The vibroacoustic stimuli were applied to the maternal abdomen above the fetal legs for a period of 1 s every 30 s. A fetal trunk movement within 1 s after stimulation was defined as a positive response. Habituation rate is defined as the number of stimuli applied before an observed non-response to four consecutive stimuli. The FHR patterns (FHRP) of the 10 min observation period before and after the tests were visually classified. Fetal states were defined according to the FHRP. Baseline FHR, FHR variability and the number of accelerations were calculated in a subgroup of 25 fetuses. RESULTS: Of the 32 fetuses that responded normally during the first test, 26 habituated and six had persistent responses. The median habituation rate decreased significantly in the second test (P=0.001). There was no difference in habituation rate between fetuses that where initially in a quiet state and those in an active state. The FHR parameters before the first test and the difference between these FHR parameters before and after the test did not correlate with the habituation rate. CONCLUSIONS: Although the majority of healthy fetuses was able to habituate, the interfetal variability in habituation performance is such that testing of habituation seems not to be a sensitive tool for the assessment of the fetal CNS. This variability is neither the result of differences in fetal state nor of the various FHR parameters before testing, nor of the difference in change of FHR parameters arising from stimulation.

Acoustic Stimulation↗

PubMed2000

Fetal learning and memory.

We used fetal habituation to repeated vibroacoustic stimulation to assess fetal memory. After the initial stimulus, we assessed the fetuses 10 min later and again after 24 h. 16 of 19 fetuses habituated rapidly to the stimuli at 10 min (p=0.004) and 24 h (p=0.042) after the initial test. We conclude, therefore, that fetuses are able to learn: they have a short-term memory of at least 10 min, and a long-term memory of at least 24 h.

Acoustic Stimulation↗

PubMed2000

Responses to vibroacoustic stimulation in a fetus with an encephalocele compared to responses of normal fetuses.

BACKGROUND: Observation of fetal movement and fetal heart rate (FHR) responses to repeated vibroacoustic stimulation (VAS) might be useful as a measure to assess fetal well-being and to assess the integrity of the fetal central nervous system (CNS). We observed the movement and FHR responses to repeated VAS of a term fetus with a serious brain anomaly as compared to responses of normal term fetuses. SUBJECTS, METHODS, RESULTS: In 37 normal term fetuses and in a term fetus with an encephalocele we studied movement and FHR response to repeated VAS. All normal fetuses responded within 1 s after stimulation with general body movement and FHR acceleration. At 36 gestational weeks, no movement or FHR responses were seen in the fetus with an encephalocele. Repetition of the test in this fetus after one week still showed no response to repeated VAS. CONCLUSION: Normal fetuses showed movement and FHR responses to external stimulation. The fetus with an encephalocele did not respond to repeated VAS with a movement or FHR acceleration. Case studies in fetuses with structural anomalies of the CNS are needed to gain insight into the spectrum of possible responses to VAS.

Acoustic Stimulation↗

PubMed1999

[Irregular blood group antibodies during pregnancy: screening is mandatory].

During pregnancy irregular blood group antibodies, originating either from earlier pregnancies or from blood transfusions, may severely jeopardize both mother and child. Three patients are described with pregnancy-associated blood group incompatibility. In one case of Kell antagonism a previous child had reportedly died of cot death, but in retrospect it had most probably suffered from erythroblastosis fetalis as a result of anti Kell antibodies. In the second case, a twin pregnancy, the diagnosis of neonatal haemolytic anaemia on the basis of blood group incompatibility with a very rare antibody (anti-Kpb) had been established in the previous child. No precautions had been taken during this pregnancy, putting both mother and children at risk. All three children recovered, the twins after repeated transfusion of Kpb-free erythrocytes. The described cases emphasize the importance of being informed about the presence of antibodies during pregnancy. Such information can only be obtained by assessing the antibody status during pregnancy. In the Netherlands, the screening of all pregnant women for the presence of irregular antibodies was introduced last year.

Adult↗

PubMed1995

Effect of drugs on chemoreceptor responsiveness in fetal sheep.

This study was designed to examine the effects of the drugs ketamine, morphine, pentobarbital, and propranolol on fetal chemoreceptor responsiveness. Eleven fetal lambs (gestational age 125-133 d) were chronically instrumented with a catheter in a hindlimb artery and vein and a forelimb artery; a carotid arterial oximeter catheter was placed in six of these fetuses. An inflatable cuff occluder was placed around the maternal hypogastric artery. Acute fetal hypoxemia was induced repeatedly by reducing uterine blood flow. Fetal heart rate, arterial pressure, and carotid arterial oxygen saturation were monitored continuously before and after administering ketamine, morphine, pentobarbital, or propranolol to the fetus. The ratio delta heart rate/delta O2 saturation has been shown previously to be a reproducible index of chemoreflex response. The differences in baseline values and changes with drugs were compared by multiple regression analysis coded by effects. Chemoreflex response was markedly attenuated by ketamine and morphine but not by pentobarbital or propranolol. Because the cardiovascular response to hypoxemia is blunted by some drugs, caution should be exercised in interpreting heart rate responses to hypoxemia in the fetus when these drugs have been administered to the mother.

Acute Disease↗

PubMed1993

Heart rate fall during acute hypoxemia: a measure of chemoreceptor response in fetal sheep.

The peripheral arterial chemoreceptor response to hypoxemia in the fetus is predominantly cardiovascular, invoking a fall in heart rate and a variable change in blood pressure. No quantifiable measure of chemoreceptor activity has yet been described in the intact fetus. We described the course, quantified the overall response, and defined the reproducibility of the heart rate response to acute hypoxemia in 22 late-term unanesthetized fetal sheep. Fetuses were chronically instrumented and studied between 1-6 days postoperatively. Acute hypoxemia was induced by occluding a balloon cuff around the common hypogastric artery. We performed 151 occlusions, starting at an initial saturation of 66 +/- 11%, decreasing saturation by 8-50%. Soon after balloon inflation, arterial oxygen saturation fell, followed by a decrease in heart rate. We calculated delta HR/delta sat, the fall in heart rate divided by the fall in saturation. Multiple linear regression analysis showed a sensitive chemoreflex, delta HR/delta sat averaging 2.5 +/- 1.2 bpm.%saturation-1. Initial saturation did not alter the first phase of the response (from the onset of the decrease in oxygen saturation to the onset of the decrease in oxygen saturation to the onset of the decrease in heart rate), but it did increase the overall response (delta HR/delta sat) when saturation was less than 65%. After adjusting in the lower range of initial saturations to that predicted at 65%, delta HR/delta sat was very reproducible within animals, with intra-animal variance being only 7% of inter-animal variance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1992

Carpal tunnel syndrome: prevalence in the general population.

To study the prevalence of carpal tunnel syndrome (CTS) in the general population and the value of brachialgia paraesthetica nocturna (BPN) in diagnosing CTS, an age and sex stratified random sample of 715 subjects was taken from the population register of Maastricht (The Netherlands) and surrounding villages, between September 1983 and July 1985. The response rate was 70%. Of these, 12 CTS cases had already been diagnosed. Of the remaining subjects, 64 (13 men, 51 women) woke up because of BPN. Among these subjects 1 man and 23 women were found to have CTS. The prevalence rate of undetected CTS was 5.8% [95% confidence interval (CI): 3.5-8.1%] in adult women; 3.4 percent (95% CI: 1.5-5.3%) had already been diagnosed as CTS. The overall prevalence rate for men was 0.6% (95% CI 0.02-3.4%). These figures have to be regarded as minimal estimates. The overall diagnostic value of BPN for CTS was 38%, while for women only this was 45% (95% CI: 31-60%).

Adult↗

PubMed1992

Chemoreceptor responsiveness in fetal sheep.

Fetal peripheral chemoreceptor responses to arterial O2 saturation and changes in PCO2 have not yet been quantitated. In 24 late-term chronically instrumented fetal sheep, we measured the heart rate response to acute hypoxemia induced by uterine arterial occlusion at various resting O2 saturations (25-86%) and at induced reductions and increases in baseline O2 saturation. As an index of fetal chemoreceptor responsiveness we calculated the fall in heart rate divided by the fall in arterial O2 saturation (delta HR/delta sat). delta HR/delta sat was inversely related to resting O2 saturation at levels less than 65%, but greater than 65% this relationship was no longer present. However, an induced increase in baseline O2 saturation from 66 +/- 12 to 76 +/- 10% decreased delta HR/delta sat from 2.6 +/- 1.6 to 1.8 +/- 1.0, indicating that when resting O2 saturation is greater than 65% there may be adaptation of peripheral chemoreceptors. Below 65%, an induced decrease in baseline O2 saturation increased delta HR/delta sat (to 3.8 +/- 1.8), suggesting a lack of adaptation to lower O2 saturations. Concomitant changes in PCO2, or differences in baseline PCO2, did not affect delta HR/delta sat during uterine arterial occlusion, which suggests that there is no interdependence between O2 and CO2 as a stimulus for the fetal peripheral chemoreceptor. However, acute hypercapnia (n = 24 in 8 fetal sheep) induced bradycardia. Furthermore, this bradycardia was related to the increase in fetal arterial PCO2. We conclude that the fetal peripheral chemoreceptor is sensitive to hypoxemia and hypercapnia and that the hypoxemia response is accentuated with decreases in initial O2 saturation.

Acute Disease↗

PubMed1992

Increased red cell aggregation does not reduce uteroplacental blood flow in the awake, hemoconcentrated, late-pregnant guinea pig.

The effect of increased red blood cell aggregation on uteroplacental blood flow was studied in 11 awake, late-pregnant guinea pigs. The aggregation of the red cells was increased by administering high molecular weight dextran (HMWD) to the previously hemoconcentrated animal. The purpose of the hemoconcentration before HMWD was 1) to use a preeclampsia model in which the hemorheology may be impaired because of the combined effect of polycythemia, an increased red cell aggregation, and an increased plasma viscosity and 2) to potentiate the aggregation-increasing effect of HMWD. Relative to the pre-HMWD condition, arterial blood pressure and systemic vascular resistance increased by 10 and 26%, respectively. The cardiac output fraction shunted across the systemic circulation and the arterial hematocrit decreased by 30 and 4%, respectively. Neither cardiac output nor the weighted organ flows, including those to the placentas, changed in response to the rise in red cell aggregation. We conclude that an imposed increase in red cell aggregation has no appreciable effect on uteroplacental blood flow in the awake and healthy late-pregnant guinea pig. These data do not exclude the possibility that increased red blood cell aggregation potentiates the negative effects on uteroplacental blood flow, e.g. in pregnancy-induced hypertension or preeclampsia, where the placenta is not only marginally perfused but also frequently damaged histologically.

Animals↗

PubMed1991

The effect of volume expansion on placental blood flow in awake hypovolemic rats in late pregnancy.

Symptomatic hypovolemia in preeclampsia is often treated by volume expansion. However, the effect of this treatment on placental blood flow is unclear. In the present study the hypothesis was tested that slow volume expansion, imposed on volume-depleted rats, does not compromise placental blood flow. Mild hypovolemia was induced in rats in late pregnancy by 24 hours' thirsting. The resulting gradual dehydration was associated with a 7% reduction in blood volume. These rats were then subjected to blood volume expansion by a continuous infusion with a plasma substitute. Volume expansion increased blood volume by 32% and cardiac output by 73%. The extra cardiac output was distributed to kidneys, carcass, and portal bed. Placental blood flow decreased by 31%. The pattern of response was comparable to the one previously observed in normovolemic rats. However, the magnitude of the changes was larger, probably associated with a delayed or impaired diuretic response. These data suggest that volume expansion therapy in mildly hypovolemic pregnant rats elicits an exaggerated hemodynamic response as compared with normovolemic rats, including placental compromise.

Animals↗

PubMed1991

Nondeformable red blood cells do not interfere with uteroplacental blood flow in the awake, late-pregnant guinea pig.

The fractional entrapment of rigidified [relative to control (labeled)] red cells after the intravascular bolus injection of a cocktail of these cells, and the concomitantly induced changes in cardiac output and its distribution (microspheres) were studied in 14 awake, late-pregnant guinea pigs. In a preceding validation study in eight nonpregnant guinea pigs, it was demonstrated that with this technique reproducible data could be generated on the fractional entrapment of rigidified red cells in all organs in this species except for lungs, liver, and spleen. In response to a bolus injection with rigidified and control red cells, only the brain showed preferential entrapment of rigidified red cells, together with a small but consistent increase in blood flow. In other organs (lungs, liver, and spleen excluded), neither preferential entrapment of rigidified red blood cells nor a consistent change in blood flow could be demonstrated. The results of our study suggest that circulating nondeformable red cells have no measurable adverse effect on the perfusion of the nondiseased hemochorial placenta in the awake, late-pregnant guinea pig. This does not exclude the possibility that rigidified red cells may increase the resistance to flow in a microcirculation that has been pathologically changed by some underlying disease.

Animals↗

PubMed1991

Hemodynamic response to volume stress in awake late-pregnant and nonpregnant rats.

The present study was designed to determine whether the often observed gestational rise in blood volume alters the hemodynamic response to volume stress relative to the nonpregnant state. Late-pregnant and nonpregnant Wistar rats, prepared with an electromagnetic flow probe around the ascending aorta and/or intravascular catheters were used for this study. One of the following sets of measurements were performed either before and after volume loading or before and after volume depletion (24 h thirst): 1) continuous monitoring of cardiac output, blood pressure, heart rate, and fluid balance (only during volume loading); 2) measurement of cardiac output and regional blood flows (microspheres); and 3) measurement of the inferior vena cava diameter (x-ray). Both rapid (bolus) and slow volume loading (infusion) led to a rise in cardiac output. The generated surplus in cardiac output was distributed to the kidneys, skeletal tissues, and intestines (only in nonpregnant rats), and was paralleled in the pregnant rats by a consistent fall in placental blood flow. Slow volume depletion had neither a consistent effect on cardiac output nor on its distribution, with even a preserved maturational rise in placental blood flow during the 24 h of thirst. Slow volume loading and depletion led to an increase and decrease of the caliber of the inferior vena cava, respectively. The nonnuterine hemodynamic response to all forms of volume stress had not changed in pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗