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Birth of St. Mary (St. Anne's parturition) in the light of messages from medical education: three examples from Croatian sacral heritage.

Christian tradition treats birth in several characteristic motives. The most frequent is the Birth of Jesus Christ, while much rarer is the apocryphal motive of the birth of St. Mary. By analyzing three paintings from Croatian 16-17th-century sacral-art heritage, depicting the parturition of St. Anne (St. Mary's Mother), the authors of this paper are trying to define the role of ethnomedical notions in the formation of modern medical and general culture.

Baths↗

Serial measurement of arterial plasma progesterone levels throughout gestation and parturition in individual rats.

Daily blood samples were taken from 6, chronically cannulated, fully conscious rats to measure plasma progesterone levels throughout gestation. Progesterone levels in individual rats fluctuated by up to 28 ng/ml per day, but tended to be consistently higher or lower than the group mean. The accuracy of predicting progesterone levels in individual rats from previous values was examined. Progesterone levels on day 7 of gestation were negatively correlated with foetal weights near term. There was little indication that high progesterone levels at any stage of gestation lead to increased foetal or placental weights. Progesterone levels on day 17 were positively correlated with the number of corpura lutea but there was little relationship between progesterone and either the number or total mass of the placentas. Serial blood samples taken from a second group of 6 rats at 2 hourly intervals showed that the time between the major fall in progesterone levels to below 12 ng/ml and the onset of parturition was relatively constant (varying by only 8 h) despite a 29 h range in the total length of gestation.

Animals↗

Interleukin 8 concentrations in amniotic fluid and peripheral venous plasma during human pregnancy and parturition.

To establish the gestational and labour-associated changes in interleukin 8 (IL-8) release, we have determined the concentration of this cytokine in maternal peripheral plasma and amniotic fluid from 15 weeks of gestation to term and in association with spontaneous-onset labour at term and preterm. No statistically significant changes in peripheral plasma IL-8 concentration were observed during pregnancy or in association with labour onset (mean concentration 56.5 +/- 14.5 ng/l, N = 64). The IL-8 concentrations in amniotic fluid were up to 50-fold greater than those observed in peripheral plasma (p < 0.05) and increased significantly (p < 0.05) during pregnancy. At term, but before the onset of labour, amniotic fluid concentrations of IL-8 averaged 969.2 +/- 553.5 ng/l (N = 12). In association with labour at term, IL-8 concentrations increased to 3895.8 +/- 1414.4 ng/l (N = 6, p < 0.03). The concentration of IL-8 in amniotic fluid obtained from women in preterm labour averaged 1854.7 +/- 1352.6 ng/l (N = 6) but was not statistically different from the concentration of IL-8 in amniotic fluid obtained from gestational aged-matched non-labouring controls. Although the precise role of intrauterine IL-8 at the time of parturition awaits elucidation, these data support the concept that this cytokine may be involved in the biochemical events associated with the onset and/or propagation of normal labour in the human.

Amniotic Fluid↗

Effect of fetal hypophysectomy on the initiation of parturition in the goat.

Fetal hypophysectomy performed between 97 and 130 days of gestation caused a significant (P is less than 0.005) prolongation of pregnancy in 5 goats in which every fetus was treated. Three of these goats gave birth spontaneously. Sham surgery or hypophysectomy of one fetus of twins had no effect on gestation length. Hypophysectomized kids, delivered after prolonged pregnancy, were significantly heavier than normal term kids (P is less than 0.005) and had lighter adrenals (P is less than 0.025). Measurements of maternal peripheral plasma concentrations of progesterone and total unconjugated oestrogens showed that the changes in goats carrying hypophysectomized fetuses were similar to those of normal pregnancy except that the prepartum oestrogen peak was absent, whether or not parturition occurred spontaneously.

Adrenal Glands↗

Correlation of rate of uterine blood flow and plasma steroid concentrations at parturition in sheep.

Blood flow transducers were placed around one uterine artery per ewe and observations of the rate of blood flow through this artery and the peripheral plasma concentrations of free, unconjugated oestrone, oestradiol and progestagens were made at intervals of 1-3 days during the last 2-3 weeks of pregnancy and at hourly intervals after spontaneous delivery at term. Rates of uterine blood flow decreased on average by 50% or more within the first hours of parturition and patterns of change in blood flow varied considerably among the animals. Spontaneous daily (pre partum) and hourly (post partum) changes in uterine blood flow were significantly correlated (P < 0.01) with the product of the concentrations of progestagens and of total free oestrogens (oestrone and oestradiol) and with the product of progestagens and oestradiol in peripheral blood.

Animals↗

Effects of placentophagy on serum prolactin and progesterone concentrations in rats after parturition or superovulation.

In rats that were allowed to eat the placentae after parturition concentrations of serum prolactin were elevated on Day 1 but concentrations of serum progesterone were depressed on Days 6 and 8 post partum when compared to those of rats prevented from eating the placentae. In rats treated with PMSG to induce superovulation serum prolactin and progesterone values were significantly (P < 0.05) elevated on Days 3 and 5 respectively, after being fed 2 g rat placenta/day for 2 days. However, feeding each rat 4 g placenta/day significantly (P < 0.02) lowered serum progesterone on Day 5. Oestrogen injections or bovine or human placenta in the diet had no effect. The organic phase of a petroleum ether extract of rat placenta (2 g-equivalents/day) lowered peripheral concentrations of progesterone on Day 5, but other extracts were ineffective. We conclude that the rat placenta contains orally-active substance(s) which modify blood levels of pituitary and ovarian hormones.

Animals↗

Uterine enzyme changes in thyroidectomized rats at parturition.

Rats were thyroidectomized at different stages of gestation and killed at parturition. Acid phosphatase of uterine horns was significantly (P < 0.05) lower in animals thyroidectomized at later stages of pregnancy, whereas alkaline phosphatase was significantly lower in those thyroidectomized earlier as compared to intact pregnant animals. The activities of glutamic oxaloacetic acid and glutamic pyruvic acid transaminases also showed significant alterations in some of the thyroidectomized animals. These 4 enzymes were also studied in the cervix but the changes showed a less distinct pattern.

Acid Phosphatase↗

Changes in the tensile properties and fine structure of the rat cervix in late pregnancy and during parturition.

The isolated cervix from non-pregnant, early Day 22 pregnant (late pregnant) and parturient rats was studied. Cyclic loading and unloading tensile tests showed that the creep properties of the cervix were greater in late pregnant than in non-pregnant rats. This change in tensile properties, or softening, was associated with a marked rise in % of water and a fall of collagen concentration (as % of wet but not dry weight). These findings, plus electron micrographs showing a marked increase in extracellular matrix, separation of bundles of collagen fibrils and active fibroblasts, suggest that softening if related to controlled tissue hydration. Cervices were also removed from 3 groups of rats killed at different times during the 3-h parturient period and creep rate measured by continuous loading. A nearly 3-fold increase in creep rate over this period indicates that there is a second stage of cervical softening in pregnancy which precedes dilatation at parturition.

Animals↗

Effect of PGF-2 alpha on uterine activity, and concentrations of 13, 14-dihydro-15-keto-PGF-2 alpha in peripheral plasma during parturition in the tammar wallaby (Macropus eugenii).

Intravenous administration of PGF-2 alpha or an analogue stimulated uterine contractility in gravid uteri during seasonal quiescence and late pregnancy. The exogenous PGF-2 alpha was metabolized to 13,14-dihydro-15-keto-PGF-2 alpha (PGFM) which was assayed in peripheral plasma by a radioimmunoassay. PGFM was cleared from the circulation with a half life of 8-15 min. Blood samples were taken approximately every 6 h from Day 26 to Day 30 from tammars which were expected to give birth on Day 27-28. Basal levels of PGFM were less than 400 pg/ml, and only occasional samples contained higher PGFM concentrations. Therefore, if uterine PGF-2 alpha release is elevated at parturition in tammars, the corresponding rise of circulating PGFM is either small or of short duration.

Animals↗

Distribution of ovarian follicular populations in the dairy cow within 35 days after parturition.

Ovaries were obtained at slaughter from 12 Holstein dairy cows at 15, 25 or 35 days after their 4th calving. Non-atretic and atretic antral follicles were separated into 6 size classes according to size and the numbers in each class were expressed as a percentage of the total for each ovary. Non-atretic follicles of diameter 0.16-0.28 mm decreased from 27.5% at Day 15 to 1.5% at Day 35 whereas those of 0.29-0.67 mm and 0.68-1.57 mm diameter increased from 37.4 to 47.2% and from 11.5 to 17.3% respectively (all P less than 0.05). The proportions of follicles measuring 1.58-3.68, 3.69-8.56 and greater than 8.56 mm remained almost constant. The atretic follicles of 0.29-3.68 mm varied significantly in number according to the post-partum interval and to whether they were in the ovary containing the CL of pregnancy. It is concluded that the CL of pregnancy and/or the conceptus have a carry-over effect on the rate of growth of the antral follicles even after parturition.

Animals↗

Influence of passive immunization against GnRH on pregnancy and parturition in the tammar wallaby, Macropus eugenii.

Pouch young were removed from 10 wallabies in lactational diapause, and half the animals were injected intravenously with 8 ml normal wallaby serum or 8 ml GnRH antiserum every 3rd day from the day of removal of pouch young until Day 30. Laparotomies were performed on Day 24 to monitor luteal size, follicular development and uterine enlargement. The pouches were examined daily for the presence of newborn young from Days 26 to 30, and all the animals were killed on Day 30. The corpora lutea had hypertrophied in all the animals of both groups by Day 24, but none of the antiserum-treated animals showed any signs of follicular development (follicles less than 1 mm diam.), whereas all the control animals had large follicles (mean 3.5 mm diam.). In each group 4/5 animals were visibly pregnant at laparotomy, and parturition occurred normally in 3 of the experimental animals and 1 of the controls. At autopsy, none of the antiserum-treated animals showed any evidence of follicular development or post-partum ovulation, whereas 3 of the controls had new corpora lutea and the other 2 had large preovulatory follicles. These differences were reflected in the weights of the lateral vaginae; the treated animals showed no evidence of oestrogenic stimulation (4.9 +/- 0.2 g), whereas the controls showed the hypertrophy characteristic of oestrus (9.5 +/- 1.2 g). Lactogenesis, as measured by an increase in mammary gland lactose concentrations, was established in all animals, regardless of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Pregnancy and parturition in rats after sympathetic denervation of the ovary, oviduct and utero-tubal junction.

The ovarian vascular pedicle and ovarian suspensory ligament were briefly frozen to destroy the nerves. Examination of sections from the ovary, oviduct and utero-tubal junction by fluorescence histochemistry showed that they were usually devoid of adrenergic nerves. Measurement of noradrenaline in segments of the uterine horn by high-performance liquid chromatography showed that the transmitter was eliminated from the upper third but not the middle or lower thirds of the uterine horn. Unilateral or bilateral denervations at metoestrus in cyclic rats did not affect either the number of ovulations or the numbers or spacing of conceptuses at Day 7 of pregnancy. Bilateral denervations on Days 4, 7 or 11 of pregnancy did not affect ovarian weights or numbers of conceptuses observed 1 week later. Plasma progesterone concentrations were at least as high in the denervated groups as in the sham-operated control groups. After unilateral or bilateral denervations at Day 15, pregnancy continued normally and birth of normal young occurred, without apparent problems, at the same time as for sham-operated rats. The mothers tended their young and allowed them to suck. It is concluded that the adrenergic innervation of the ovary in the rat is not required for its normal function during pregnancy; that of the oviduct and mesosalpinx is not required for ovum pick-up or for transport of oocytes, spermatozoa or early embryos; and that of the utero-tubal junction is not required for uterine motility involved in embryo spacing and parturition.

Adrenergic Fibers↗

Effects on maternal and fetal steroid concentrations of induction of parturition in the sheep by inhibition of 3 beta-hydroxysteroid dehydrogenase.

Changes in circulating steroid hormones, the incidence of myometrial contractions, and the onset of labour were all monitored after administration of the 3 beta-hydroxysteroid dehydrogenase inhibitor, epostane, to chronically catheterized ewes and fetuses near term. In all animals the drug induced delivery 33-36 h after injection or infusion into the ewe with the birth of live healthy lambs which showed normal subsequent development. Epostane induced immediate, permanent falls in both maternal and fetal plasma progesterone concentrations, accompanied by increased PGF metabolite concentrations in the uterine vein beginning 15 min after treatment. Of the other hormonal changes observed, the most striking was the pronounced drop in both maternal and fetal plasma cortisol. In the fetus this fall was followed by increasing concentrations of circulating ACTH which eventually restored the cortisol levels. By 12-24 h after epostane a substantial overshoot had occurred and at 27-30 h the fetal plasma cortisol concentrations were as high as those seen during normal parturition at term. No significant changes in maternal plasma oestradiol-17 beta could be detected after epostane treatment or during labour. The incidence of slow myometrial contractions increased significantly during the second 3-h period after epostane, although their duration did not change. Contraction patterns typical of first stage labour were seen from 20 to 24 h. These results show that epostane may be used as a safe, predictable inducing agent in sheep if given 6-10 days before term; the lambs showed no signs of prematurity despite their lowered plasma cortisol concentrations which persisted for some hours before labour was induced.

3-Hydroxysteroid Dehydrogenases↗

Functional and morphological characteristics of the first corpus luteum formed after parturition in ewes.

The ability of sheep luteal cells from the first corpus luteum formed after parturition (Group F) to secrete progesterone in the presence or absence of LH was compared with that of luteal cells obtained from normal cyclic ewes (Group C). Luteal concentrations of receptors for LH and prostaglandins (PG) F-2 alpha (PGF-2 alpha) and the cellular composition of corpora lutea from Groups F and C were also compared. Luteal cells from Group F secreted less progesterone in either the presence or absence of LH (P less than 0.01). There was no difference in the number of receptors for LH or PGF-2 alpha per luteal cell between Groups F and C (P greater than 0.1), nor was there a difference in the number of large or small steroidogenic luteal cells (P greater than 0.1). It was concluded that, if short-lived corpora lutea are insensitive to gonadotrophins, this response is not mediated by decreased numbers of receptors for LH. In addition, if the first corpus luteum formed post partum in ewes is more sensitive to the luteolytic effects of PGF-2 alpha, this effect is not mediated by an increased number of receptors for PGF-2 alpha or an increased proportion of PGF-2 alpha-sensitive large luteal cells.

Animals↗

Effects of reducing the remating interval after parturition on the fertility and plasma concentrations of luteinizing hormone, prolactin, oestradiol-17 beta and progesterone in lactating domestic rabbits.

Primiparous crossbred does were remated on Day 1 (n = 15) or 14 (n = 25) post partum and killed on Day 10 post coitum to assess their fertility. Blood samples were taken during the pre- (0-12 h post coitum) and post- (1-10 days post coitum) ovulatory periods and plasma was assayed for luteinizing hormone (LH), prolactin, oestradiol-17 beta and progesterone. Ovulation response was significantly greater (P less than 0.01) and ovulation rate significantly lower (P less than 0.001) in does mated on Day 1 than in those mated on Day 14 post partum. Does failing to ovulate on Day 14 post partum exhibited no preovulatory LH surge and had significantly lower (P less than 0.05) premating concentrations of oestradiol-17 beta and prolactin than those ovulating at this time. No significant differences in hormone concentrations were observed during the preovulatory period between does ovulating on Days 1 and 14 post partum, with the exception of oestradiol-17 beta. Concentrations of this hormone were significantly lower (P less than 0.01) in does mated on Day 1, at 1 h post coitum. We conclude that (i) fertility was affected by the remating interval after parturition, (ii) ovulation failure was associated with an absence of the preovulatory LH surge and a reduction in premating concentrations of oestradiol-17 beta and prolactin and (iii) the lower ovulation rate in early lactation was apparently caused by a reduction in ovarian competence to respond to the gonadotrophic stimulus.

Animals↗

Release of an oxytocic peptide at parturition in the marsupial, Macropus eugenii.

The oxytocic peptide mesotocin was measured in plasma samples collected throughout pregnancy in the conscious tammar wallaby, Macropus eugenii. Plasma mesotocin and the prostaglandin metabolite 13,14-dihydro-15-oxo-prostaglandin F2 alpha were also assessed immediately prepartum and during parturition. A radioimmunoassay for mesotocin was validated in the tammar and this assay allowed direct measurement in 50 microliters unextracted plasma with a sensitivity of 12.5 pmol l-1. Plasma concentrations of mesotocin remained basal (approximately 15 pmol l-1) at all stages of pregnancy, including prepartum. A significant (P < 0.05) increase in plasma mesotocin was observed only immediately after delivery of the neonate and this increase was maintained for at least 15 min postpartum. Mesotocin concentrations returned to basal values 2 h after birth. Peak concentrations of mesotocin of 516.7 +/- 108.1 pmol l-1 were measured within 2 min of birth. This peak coincided with a short-lived peak in concentration of prostaglandin F2 alpha metabolite immediately after birth (2.1 +/- 0.4 nmol l-1) which decreased to less than 0.3 nmol l-1 within 2 h postpartum. These data demonstrate that mesotocin is released during, or immediately after, delivery and appears to parallel the profile of circulating prostaglandin F2 alpha metabolite in this marsupial.

Animals↗

Role of PGF2alpha and oxytocin in parturition in the brushtail possum (Trichosurus vulpecula).

Maturation of the fetal pituitary and adrenal glands allows the secretion of cortisol, which in turn leads to an increase in prostaglandin and mesotocin production. The production of prostaglandin and mesotocin results in an increase in uterine contractions and initiates birth in marsupials. The major metabolite of PGF(2alpha), 13,14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM), has been found in the plasma of the possum at the time of birth and administration of PGF(2alpha) to female possums induced the adoption of the birth position. Evidence that mesotocin is an integral hormone of birth in the tammar wallaby indicates that both PGF(2alpha) and mesotocin or oxytocin are required for marsupial birth. The presence of PGF(2alpha) receptors in the uterus and corpus luteum of the possum, and the in vitro uterine responsiveness to PGF(2alpha) or oxytocin, were examined. PGF(2alpha) receptors were not observed in possum uteri and the inability of PGF(2alpha) to cause contractions indicates that PGF(2alpha) is not involved directly in contraction of the uterus at parturition. The presence of oxytocin and mesotocin receptors in the uterus of possoms and the ability of oxytocin to induce uterine contraction in vitro supports the view that mesotocin is required for expulsion of the young from the uterus. Low numbers of PGF(2alpha) receptors were found in the possum corpus luteum at birth, indicating an involvement of PGF(2alpha) in regression of the corpus luteum.

Animals↗

Oxytocin: a paracrine hormone in the regulation of parturition?

The role of oxytocin in parturition is controversial. When considered as an endocrine hormone, the balance of evidence suggests that oxytocin has little involvement in the initiation of labour. However, recent research has demonstrated synthesis of mRNA encoding oxytocin within the pregnant human uterus. This article reviews the hypothesis that oxytocin is an important paracrine (or autocrine) hormone with respect to the control of myometrial contractility in late gestation. Experimental data are provided from humans when possible and from studies using the rat as an experimental model. The processing of oxytocin prohormones in uterine tissues is reviewed and the presence and possible role of carboxy-extended forms of oxytocin in late gestational tissues of rats are discussed. The regulation of oxytocin and its receptor, particularly by oestrogen and progesterone, is reviewed. The inter-relationship between oxytocin and prostaglandins is discussed. Finally, the metabolism of oxytocin within intrauterine tissues and the recent development of specific antagonistic analogues to oxytocin are considered. It is concluded that further clarification of this paracrine system within intrauterine tissues during late gestation could lead to more successful strategies for preventing or arresting preterm labour in women.

Animals↗