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Biomedical subjects

O Behrens

Publications and source records attributed to O Behrens.

At least 19 recordsLinked to original sources
PubMed2000

Apparent up-regulation of stimulatory G-protein alpha subunits in the pregnant human myometrium is mimicked by elevated smoothelin expression.

Sensitization of adenylyl cyclase (AC) by increased expression of large isoforms of the stimulatory G-protein Galpha(s) has been suggested as a mechanism that governs uterine quiescence during pregnancy. We quantified several components of the AC pathway in pregnant (P, n=21) and nonpregnant human myometria (NP, n=10). AC activity was approximately sevenfold higher in P than in NP under basal and stimulated conditions (MnCl(2)/GTP/GTP + isoproterenol). In addition, relative stimulation (% of basal) by 5'-guanosine-betagamma-iminotriphosphate and forskolin was twofold higher in P. beta-Adrenoceptor density was low and unaltered in P. Galpha(s) mRNA splice variants did not differ in P. Using antisera against different epitopes of Galpha(s) (carboxyl-/more amino-terminal), we found unchanged expression of Galpha(s) short and long (45, 47 kDa) in P. Two additional proteins in P (51, 59 kDa) were detectable only by the carboxyl-terminal antiserum and lacked GTP binding properties. The 59 kDa protein could be identified as a recently discovered cytoskeletal protein, smoothelin, which was 10-fold increased in P. These data indicate that the apparent up-regulation of large Galpha(s) species in P is mimicked by elevated smoothelin. Therefore, the increase in AC cannot be attributed to changes in Galpha(s)- or beta-adrenoreceptors. Epitope sharing between Galpha(s) and smoothelin should be considered in experiments on smooth muscle tissues.

5'-Nucleotidase↗
PubMed1999

[Efficacy of ultrasound screening in pregnancy].

OBJECTIVE: The purpose of this study was to examine the effectiveness of ultrasound screening in pregnancy. MATERIAL AND METHODS: Therefore, it was registered whether fetal malformations in a study population of 11,172 deliveries were already diagnosed before birth. RESULTS: 341 defects were found in 297 children from mothers who had had prenatal care. Most anomalies were seen in the urogenital tract (n = 98; 28.7%), the heart (n = 67; 19.6%), the connective tissue (n = 39; 11.4%), the gastrointestinal tract (n = 32; 9.4%), and in the central nervous system (n = 33; 9.7%). Chromosomal anomalies (n = 22; 6.5%) and orofacial defects (n = 21; 6.2%) were more rare. 8.8% of all defects were lethal, 37% severe. 237 (69.5%) were classified as "diagnosable by ultrasound prenatally". 125 of them (53%) were identified prenatally, with high rates of 71% in central nervous system, 65.5% in intestinal and 54% in urogenital tract, while the detection rate was only 13.6% in chromosomal and 3.3% in cardiac defects. Only 14.3% were found before 24 weeks of gestation. CONCLUSIONS: Thus, the effectiveness of ultrasound screening has to be improved by adequate measures.

Adolescent↗
PubMed1998

Oxytocin and vasopressin 1a receptor gene expression in the cycling or pregnant human uterus.

OBJECTIVE: Our purpose was to compare concentrations of messenger ribonucleic acid specific for the oxytocin receptor and for the vasopressin 1a receptor in myometrial and endometrial tissues of pregnant and nonpregnant women. STUDY DESIGN: Tissues from pregnant uteri were obtained from 95 women who were undergoing cesarean delivery between 26 and 42 weeks' gestation. Tissues from nonpregnant uteri were obtained from 7 cycling women who were undergoing hysterectomy. The competitive reverse-transcription polymerase chain reaction method was used to determine messenger ribonucleic acid concentrations. RESULTS: A significant increase in oxytocin receptor messenger ribonucleic acid was found during the first half of pregnancy. Oxytocin receptor messenger ribonucleic acid concentrations were lower in tissues with spontaneous contractions than in quiescent tissues and were decreased in patients with advanced labor. Vasopressin 1a receptor messenger ribonucleic acid concentrations were high in tissues from both cycling and pregnant uteri but remained unchanged throughout gestation. CONCLUSION: The increase in oxytocin receptor protein concentrations seen in pregnancy is only partially controlled by messenger ribonucleic acid abundance. High concentrations of vasopressin 1a receptor messenger ribonucleic acid confirm the biologically active role of this receptor in both the cycling and the pregnant uterus.

Endometrium↗
PubMed1997

[Rhesus prophylaxis--history and current status].

The varying symptoms of rhesus incompatibility were recognized and described approximately sixty years ago. Jörg Schneider, then at the Freiburg University Hospital in Germany, had been the very first investigator to perform rhesus prophylaxis in pregnant women. The exact date of this achievement is August 9, 1963. One year later, Schneider could report on nine women, who-following delivery of a rhesus-positive child-did not develop rhesus antibodies during a subsequent pregnancy with a rhesus-positive fetus. Since the late sixties, rhesus prophylaxis has been an integral part of prenatal care in Germany. In the meantime, the role of ante-partum prophylaxis has also been established. Since the introduction of post-partum rhesus prophylaxis, fetal morbidity and mortality has been reduced by 90 percent.

Erythroblastosis, Fetal↗
PubMed1996

[Prognostic value of cardiotocography in pregnancy with pathologic Doppler findings].

Absent (absent-EDF) or reversed (RF) end-diastolic flow in Doppler velocimetry in the umbilical artery and fetal aorta indicates highly disturbed fetoplacental perfusion, which often occurs early in pregnancy. Perinatal mortality and morbidity is very high. In this situation it is not clear how long pregnancy can be continued to achieve better conditions for the preterm fetus. This study was performed to investigate the value of fetal heart rate recordings (FHR) in patients with absent EDF or RF as a parameter to determine the optimum time of delivery. 25 pregnancies with absent (n = 21) or reversed end-diastolic velocity (n = 4) were analysed. Gestational age was between 24 and 34 weeks. 17 children showed compensatory dilatation of the middle cerebral artery (68%). 15 (60%) were growth retarded, 8 of them below the 3% percentile, while 3 had normal weight. Maximum time interval until delivery was 18 days, median was 2 days. Five children died before, 2 during delivery. As none died after delivery, perinatal mortality was 28%. 4 of the survivers (22%) showed arterial acidosis. Only three children had completely normal fetal heart rate recordings on the day of diagnosis of absent EDF or RF. All others showed at least suspicious FHR (according to Hammacher), 8 of them (32%) even pathological FHR, including all children who died later. Early suspicious changes in FHR were the reduction in frequency and amplitude of oscillation, while decelerations occurred later. Additional unfavourable parameters in FHR were roundings of the oscillatory inversions as well as missing reactivity to fetal movements. Fetal heart rate monitoring is a reliable tool for determination of the optimum time of delivery in children with absent EDF or RF. The decision has to be made in relation to the gestational age. If possible, the fetus should be born before FHR becomes pathological. In this manner perinatal mortality and morbidity should be kept at a low level even in high-risk patients with absent EDF or RF.

Blood Flow Velocity↗
PubMed1994

[Induced labor with prostaglandin E2 gel after previous cesarean section].

With the rising rate of Caesarean sections, the number of pregnant patients with a previous Caesarean is increasing. Taking into consideration certain contraindications, it seems to be justified, to attempt induction of labour for vaginal delivery without major risk. However, the use of prostaglandins for cervical ripening in women with an unfavourable cervical status is particularly controversial. Thus, we analysed data from 385 trials of vaginal labour induction in a total of 522 patients with previous Caesarean section. Single or multiple cervical doses of prostaglandin-E2-gel had to be administered because of an unripe cervix (Bishop-score < 8) in 161 women for induction of labour for medical indications. 84.9% of those patients, in which labour induction was attempted after previous Caesarean section, delivered vaginally; 70% after two Caesareans. The highest success rates were seen after previous Caesarean for breech presentation, while there was still a vaginal delivery rate above 60% even after Caesarean for cephalopelvic disproportion or failure to progress. Maternal and foetal complications were seen with equal incidence in both study groups. Uterine ruptures totalling 0.5% were seen only in patients without cervical priming. Taking into consideration contraindications, intracervical application of PGE2-gel is a safe and effective method, even in patients after previous Caesarean section with clear advantages in case of an unripe cervix.

Administration, Intravaginal↗
PubMed1993

Effects of lumbar epidural analgesia on prostaglandin F2 alpha release and oxytocin secretion during labor.

The concentrations of plasma oxytocin and prostaglandin F2 alpha metabolite (PGFM) were measured in 10 parturients with and 10 without lumbar epidural analgesia. A blood sample was taken immediately before analgesia and another 60 min later. The control patients were matched for the stage of cervical dilatation at the time of the first blood sample; the second was drawn 60 min later. Plasma PGFM decreased significantly after lumbar epidural anesthesia and increased in controls resulting in a highly significant difference between the groups (P < 0.005). Plasma oxytocin concentrations levels also changed in opposite directions in the two groups but the difference did not reach statistical significance (P < 0.1). Uterine activity increased in the controls and decreased in the analgesia group resulting in a significant difference between the groups (P < 0.05). All subjects delivered vaginally. The total duration of labor was longer in the analgesia group (7.8 +/- 1.0 h vs. 4.7 +/- 0.6 h; P < 0.05) as was the duration after analgesia (5.1 +/- 0.9 h vs. 2.5 +/- 0.8 h; P < 0.05), whereas the duration of the second stage was not significantly different. We conclude that lumbar epidural anesthesia results in suppression of PGF2 alpha release which may be the cause of the diminished uterine activity and the prolonged duration of the first stage of labor.

Adult↗
PubMed1993

[Antibody detection after antepartal rhesus prophylaxis: normal values or sensitization].

Antibody screening tests were performed in 29 unsensitized pregnant women after antepartum Rh immune prophylaxis, using the indirect Coombs test (ICT) and a more sensitive ID-microtyping-system (IDM). With the ICT, anti-D antibodies were detected in 85% for at least 4 weeks and at most 8 weeks after immunisation. The maximum titer was 1:8. With the IDM, 97% showed antibodies against 'D' for at least 4 weeks and at most 11 weeks with a maximum of 1:16. The IDM titer was always 1 to 3 steps more sensitive than the ICT. After postpartum Rh immune prophylaxis, anti-D titers were again positive in many of the patients (ICT: 42%; IDM: 60%). In conclusion, it is nearly always possible to measure antibodies against 'D' after antepartum Rh immune prophylaxis and IDM was superior in comparison to ICT. However, maternal isoimmunisation to the rhesus antigen cannot be excluded for sure and patients have then to be controlled. As isoimmunisation could not be confirmed in any of our patients, postpartum Rh immune prophylaxis has to be administered even after detection of an antibody titer against 'D' after antepartum Rh prophylaxis.

Coombs Test↗
PubMed1993

Plasma prostacyclin and thromboxane concentrations in 160 normotensive, hypotensive, and preeclamptic patients during pregnancy, delivery, and the post partum period.

Plasma concentrations of 6-keto-prostaglandin F1 alpha, a stable metabolite of prostacyclin, and TxB2 were measured in 160 women during pregnancy (n = 106), delivery (n = 40), and in the postpartum period (n = 14). Fifty nine patients had normal blood pressure, 10 had mild and 9 severe preeclampsia while 38 patients were hypotensive. Normotensive patients were grouped according to their gestational age: 22-26 weeks (n = 22), 27-31 weeks (n = 22), and 32-38 weeks (n = 15). 20 patients were in early first stage of delivery (cervical dilatation < or = 5 cm), 20 patients in late first stage (cervical dilatation > or = 6 cm). The concentration (mean value +/- SEM) of the PGI2 metabolite tended to increase during pregnancy without reaching significance (218 +/- 11; 225 +/- 10; 250 +/- 15 pg/ml). At the same time, TxB2 showed a decrease, which was most pronounced at 27-31 weeks (65 +/- 15; 40 +/- 2; 48 +/- 4 pg/ml; p < 0.001). The ratio of PGI2/TxA2 increased in parallel (4.9 +/- 0.4; 6 +/- 0.4; 4 +/- 0.5). There was no difference in plasma concentrations of PGI2 (figure 4) and TxA2 in patients with normal blood pressure, mild preeclampsia and hypotension, whereas in severe preeclampsia, the plasma concentration of PGI2 was significantly lower (p < 0.001) and of TxA2 significantly higher (p < 0.001). The ratio of PGI2/TxA2 shifted significantly to vasoconstriction in patients with severe preeclampsia (p < 0.0001) and to vasodilatation in those with hypotension (p < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Epoprostenol↗
PubMed1992

Correlation of nocturnal increase in plasma oxytocin with a decrease in plasma estradiol/progesterone ratio in late pregnancy.

OBJECTIVES: Our purpose was to determine whether plasma oxytocin concentrations show a daily rhythm. STUDY DESIGN: Ten women between 37 and 39 weeks of gestation volunteered for the study. They were admitted 1 to 2 days before the experiment. Three blood samples were taken with 2-minute intervals each time, at 8 AM, 4 PM, and 12 midnight. Oxytocin, 17 beta-estradiol, progesterone, and cortisol were measured by radioimmunoassay with highly specific antibodies. Statistical analysis of variance by Friedman's test was followed by multiple range testing, and p < 0.05 was considered significant. RESULTS: Significant daily rhythm was found for plasma cortisol, progesterone, and oxytocin and for the estradiol/progesterone ratio. Oxytocin showed a nocturnal peak and a strong negative correlation with the estradiol/progesterone ratio. CONCLUSIONS: The daily rhythm in plasma oxytocin parallels the rhythm in uterine activity (shown by others), suggesting a causal relationship between the two. Both may in turn be related to the ratio of circulating estradiol and progesterone.

Circadian Rhythm↗
PubMed1992

Oxytocin and bovine parturition: a steep rise in endometrial oxytocin receptors precedes onset of labor.

Oxytocin receptors were measured in myometrium and intercaruncular endometrium of cows during pregnancy and parturition. Concentrations of estradiol-17 beta, estrone, and progesterone in peripheral blood were also measured. Receptor concentrations in the endometrium rose almost 200-fold from Day 20 to term (p < 0.0001, ANOVA), from 40 +/- 11 to 7300 +/- 1430 fmol/mg protein. Myometrial receptor concentrations increased 10-fold from 180 +/- 36 fmol/mg on Day 20 to 1850 +/- 360 fmol/mg protein at term (p < 0.0001, ANOVA). During labor, endometrial receptors (6600 +/- 1300 fmol/mg) remained at prelabor values, whereas myometrial receptor concentrations had decreased to 1190 +/- 316 fmol/mg (not significant) and declined further postpartum. Plasma concentrations of progesterone declined from 4-5 ng/ml to about 2 ng/ml between Days 250 and 282 and dropped to < 0.2 ng/ml shortly before delivery. Plasma concentrations of estrone and estradiol-17 beta were below 10-20 pg/ml until Day 230. Estrone concentrations were significantly (p < 0.05) increased by Day 250 and estradiol-17 beta by Day 270, and then both rose rapidly. During labor, plasma estrone was 1135 +/- 245 pg/ml and plasma estradiol-17 beta was 226 +/- 131 pg/ml. The molar ratio of estrone and estradiol-17 beta to progesterone rose from less than 0.01 to 4.4 during labor, and was correlated with oxytocin receptor concentrations in endometrium (r = 0.5160, p < 0.001), but not those in myometrium (r = 0.0122). The regulation of oxytocin receptors by ovarian hormones in the two tissues may therefore differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Antenatal diagnosis of a rare combined fetal malformation: acardius acephalus and single ventricle of the twin.

The development of an acardius in a monozygotic multiple pregnancy has been reported in more than 200 cases. We present the case of an acardius acephalus in a twin pregnancy additionally complicated by a serious cardiac malformation of the donor twin (single ventricle). Antenatal diagnosis and development as well as intrauterine treatment of the donor twin from 26 to 34 weeks of gestation are described.

Abnormalities, Multiple↗
PubMed1991

Alpha-Fetoprotein and renal dysfunction of the fetus.

Alpha-fetoprotein (AFP) levels were measured in 25 pregnancies with renal dysfunction of the fetus. Oligohydramnios was found in 14 of 16 patients diagnosed by 20 weeks of gestation and in all of those diagnosed later. AFP levels in maternal serum were normal in 17 (68%), elevated in five (20%), and low in three patients (12%). AFP serum levels up to 24 weeks of gestation were significantly higher than after 24 weeks. AFP levels in amniotic fluid obtained from amniocentesis in six patients were normal or slightly elevated. We suggest that the concentration of AFP in amniotic fluid and maternal serum does not only depend on the physiologic proteinuria of the immature fetal kidneys but also on the permeability of the not yet keratinized fetal skin and the diluting volume of the amniotic fluid.

Amniotic Fluid↗
PubMed1991

Plasma oxytocin but not prostaglandin F2 alpha metabolite levels at cerclage may predict preterm delivery.

Plasma oxytocin and prostaglandin F2 alpha metabolite (PGFM) concentrations were measured in 45 patients admitted for cerclage during the second trimester. Samples were collected before, 3 hours after, and 3 days after the Shirodkar procedure. Uterine activity was recorded by external tocography twice daily for 30 minutes. Twenty-eight women with uncomplicated pregnancy and commensurate gestational age served as controls. Cervical length, measured by ultrasonography, was significantly shorter before cerclage (36 +/- 2 mm) than after cerclage (43 +/- 2 mm) or compared with controls (48 +/- 1 mm). Bishop scores ranged from 3-6 (median 4) in the cerclage group and 0-1 (median 0) in controls. Fifteen cerclage patients and one control delivered preterm 5-22 weeks after the procedure. Initial plasma PGFM levels were significantly higher in cerclage patients than in controls. The cerclage procedure caused an immediate rise in plasma PGFM and a subsequent fall below initial levels to control values. Neither the initial levels of PGFM nor the increments 3 hours after cerclage correlated with the outcome of pregnancy. By contrast, plasma oxytocin levels before cerclage were significantly higher in patients who subsequently delivered preterm than in those who delivered at term. Cerclage resulted in a significant fall in plasma oxytocin at 3 hours in patients with preterm delivery, but after 3 days the oxytocin levels had returned to the precerclage values. Patients who had increased uterine contractions had significantly higher plasma oxytocin levels but lower PGFM levels than those without contractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Dinoprost↗