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Biomedical subjects

O Behrens

Publications and source records attributed to O Behrens.

11 recordsLinked to original sources
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↗
PubMed1990

Oxytocin and vasopressin binding sites in human and bovine ovaries.

Human ovarian tissue and bovine ovarian stroma and follicles bound tritiated oxytocin and tritiated arginine vasopressin with similar affinity, whereas bovine corpora lutea bound tritiated oxytocin only. Competition for the binding of tritiated oxytocin by various agonists and antagonists was suggestive of receptor function. The number of oxytocin binding sites varied cyclically in all tissues. In bovine ovarian stroma and corpora lutea the concentrations were lowest on day 14 and highest on days 17, 19, and 21 after ovulation, with a striking peak in the luteal concentration on day 19. In human ovarian tissues the concentrations also were highest in samples obtained in late luteal phase. In large follicles the concentration of oxytocin binding sites was highest on the day of estrus and lowest on day 7. In bovine ovary the number of arginine vasopressin binding sites was approximately 50% lower than oxytocin binding sites and the cyclic variations were not significant. Human ovarian tissue had similar numbers of oxytocin and arginine vasopressin binding sites. Because bovine ovaries produce oxytocin and arginine vasopressin the results suggest a paracrine or autocrine role for these neuropeptides in luteolysis and ovulation. Although their synthesis in human ovaries is still controversial the presence of binding sites suggests a physiologic role in the regulation of human ovarian function as well.

Analysis of Variance↗
PubMed1990

Oxytocin and vasopressin receptors in bovine endometrium and myometrium during the estrous cycle and early pregnancy.

The binding of [3H]oxytocin ([3H]-OT) and [3H]arginine vasopressin ([ 3H]-AVP) by bovine endometrial and myometrial membrane preparations obtained on days 0, 7, 14, 17, and 21 after estrus or mating was investigated. [3H]OT was bound with higher affinity than [3H]AVP by both tissues; the mean dissociation constants (KdS) were 0.95 x 10(-9) M and 1.56 x 10(-9) M for OT and AVP, respectively, P less than 0.0001, with no significant variations in the KdS during the cycle. The concentration of [3H]OT binding sites was on the average 50% higher than [3H]AVP across the cycle in both tissues. Endometrial receptor levels varied significantly during the cycle; it was lowest on days 7 and 14, rose significantly on day 17, and peaked on day 21. Myometrial receptor levels decreased from levels at estrus on days 7 and 14, but the changes were not significant. The ratio between endometrial and myometrial receptor concentrations changed from about 10 at estrus to less than 1 in the luteal phase. In early pregnancy, the receptor levels did not differ from nonpregnant levels on days 7 and 14, but on day 17 the endometrial receptor concentrations were significantly lower, and on day 21 those in both tissues were significantly lower. The endometrial OT and AVP receptor concentrations were inversely correlated with plasma progesterone levels (P = 0.005) with no correlation to plasma estradiol, whereas the myometrial receptor concentrations showed no correlation to plasma progesterone but an inverse correlation with plasma estradiol (P = 0.004). We conclude that the endometrial OT and AVP receptor concentrations are more tightly controlled by progesterone than myometrium, and that the bovine conceptus suppresses endometrial OT and AVP receptor concentrations in the preattachment stage either by a local action on the endometrium or indirectly via an antiluteolytic effect.

Animals↗
PubMedDate not supplied

[Doppler ultrasound in monitoring twin pregnancies with early discordant growth].

Early growth retardation in one twin is complicated by a high fetal mortality and morbidity. It is often very difficult to determine the optimum time of delivery in regard to placental insufficiency and prematurity. We report of two cases in which doppler velocimetry was a helpful method in monitoring those pregnancies at high risk. A growth retardation of three weeks was found in one child of a twin pregnancy at 17 weeks of gestation. Doppler velocimetry at 23 weeks showed a reverse flow and centralisation and the child died at 27 weeks. The other twin then also developed pathologic flow patterns and had to be delivered by cesarean section. In the second patient, pregnancy could be continued in spite of a growth retardation of three weeks in one child at 15 weeks and an additional decrease in the growth rate of both children from 30 weeks onwards. Cesarean section had to be performed at 34 weeks because of premature rupture of membranes.

Adult↗
PubMedDate not supplied

[Pregnancy follow-up of a twin pregnancy with acardius acephalus].

Beginning with the 20th week of gestation a monoamniotic twin pregnancy with acardius acephalus was intensively observed by ultrasound and doppler ultrasound. The acardius only grew until the 24th week of gestation; the fetus underwent a normal development during the entire pregnancy. Doppler ultrasound showed low resistance indices in both umbilical arteries. During the 24th week of gestation the flow in the umbilical artery of the acardius could no longer be registered due to a cessation of development. A normal flow could be registered from the 28th week of gestation until the end of pregnancy in the umbilical artery, aorta fetalis and the art. cerebri med. of the fetus. During the 36th week of gestation the fetus died because of umbilical cord entanglement with the cord of the acardius.

Anencephaly↗
PubMedDate not supplied

[Vaginal sonographic follow-up of embryo development].

The clinical study reports on facilities of transvaginal sonography to demonstrate early embryological structures. A collective of 659 sonographical examinations in 593 women between 4. and 13. week of gestation (wog) is described. The earliest imagery of an intrauterine pregnancy could be performed at 28. day post menstruation (p.m.) and first heard beats could be detected at 36./37. day p.m.. The secondary yolk sac could be discovered at the end of 5. wog and first motions of the embryo in 8. wog. Certain structures as parts of the skull, brain and spine were clearly to be differentiated in 10.-12. wog. Transvaginal sonography renders an very early and comprehensive control of regular embryological growth and development. Striking malformations are early detected.

Embryonic and Fetal Development↗