Serologic study of human parvovirus B19 infection in pregnancy in Japan.

OBJECTIVES: To clarify the relationship between hydrops fetalis and parvovirus outbreaks in the community, seroprevalence of B19 antibody among women of childbearing age, and adverse effects of intrauterine B19 infection. METHODS: Sera were collected from 168 cases of hydrops fetalis which were diagnosed between 1987 and 1997 in Miyagi prefecture, Japan, from 232 healthy pregnant women in 1987 and 277 healthy pregnant women in 1997 in Miyagi, and from 48 women infected with B19 during pregnancy. The sera were examined for B19 IgG and IgM antibodies by enzyme-linked immunosorbent assay and for B19 DNA by polymerase chain reaction. The number of cases of erythema infectiosum in Miyagi had been monitored each month. RESULTS: Thirteen of the 168 cases of hydrops fetalis were found to be caused by intrauterine B19 infection and 12 of the 13 cases clustered in two periods of outbreaks of erythema infectiosum in the community. The positive rates of B19 IgG antibody between 1987 and 1997 were significantly different: 33% in 1987 and 46% in 1997. Nine of the 48 women infected during pregnancy showed adverse effects of the fetus: eight hydrops fetalis and one early abortion with positive B19 DNA. The fetal death rate (>12 weeks of gestation) among them was 15% (7/48), far higher than the calculated 1% among the general population. The nine mothers with adverse fetal outcomes had contact with the infectious source at the 16 weeks of gestation or earlier. CONCLUSIONS: These data clearly showed a relationship between hydrops fetalis and parvovirus outbreaks in the community, and it may be important to follow the seroprevalence for an extrapolated period time to predict occurrence of hydrops fetalis caused by B19. Also the data indicated that the gestational week infection occurred is the most important determinant of an adverse effect to the fetus as described previously.

Immunoreactive corticotropin-releasing hormone in amniotic fluid.

Immunoreactive corticotropin-releasing hormone in the amniotic fluid of both human beings and rats was measured by a specific radioimmunoassay. In human subjects the hormone was detectable in all amniotic fluid samples (obtained during the sixteenth and eighteenth weeks of gestation) (2.5 +/- 1.7 fmol/ml, mean +/- SD, n = 17) and the thirty-eighth to fortieth weeks (9.3 +/- 5.4 fmol/ml, n = 24). The levels of concentration of this hormone in this amniotic fluid correlated significantly with the levels in both maternal plasma and placenta for each patient. Gel filtration of amniotic fluid extracts revealed two major peaks of immunoreactive corticotropin-releasing hormone, one at the elution position of the rat hormone and the other at a small-molecular-weight region. Immunoreactive corticotropin-releasing hormone was not detectable in rat amniotic fluid or placenta. We concluded that immunoreactive corticotropin-releasing hormone, which may be derived from the placenta, is present in human amniotic fluid and that its detection in the human placenta but not in rat placentas suggests that the mechanism of corticotropin-releasing hormone gene expression in the placenta is species specific.

Placental corticotropin-releasing hormone may be a stimulator of maternal pituitary adrenocorticotropic hormone secretion in humans.

To clarify the physiological role of placental corticotropin-releasing hormone (CRH), we measured plasma CRH, ACTH, and cortisol throughout pregnancy. Cerebrospinal fluid (CSF) CRH levels and ACTH responsiveness to synthetic CRH were also quantified in pregnant and nonpregnant women. Maternal plasma CRH levels, which increased progressively during pregnancy, correlated well with both ACTH and cortisol in early labor, delivery, and postpartum samples, and also with cortisol levels in samples before labor. CSF CRH levels in term pregnant women did not differ from those of nonpregnant women. CRH infusion that attained similar plasma CRH levels to those found in late pregnancy elicited significant ACTH release in vivo and regular CRH test provoked normal ACTH response during early pregnancy but no response during late pregnancy. We concluded that: (a) maternal pituitary-adrenal axis correlates well with plasma CRH levels, which are high enough to provoke ACTH release from maternal pituitary; (b) hypothalamic CRH secretion in term pregnant women is not exaggerated; and (c) maternal pituitary is responsive to synthetic CRH in early but not late pregnancy, suggesting that maternal pituitary-adrenal axis is already activated by high circulating CRH. Placental CRH may be an important stimulator of the maternal pituitary-adrenal axis during pregnancy.

[Screening for chromosomal anomalies with maternal serum alpha-fetoprotein].

Between July 1, 1986 and January 31, 1988, genetic amniocentesis was performed on 205 patients. The maternal serum alpha-fetoprotein (AFP) and amniotic fluid AFP levels were measured by enzyme immunoassay. Gestational dates were confirmed by sonography, and AFP results were expressed as multiples of the median (MOM). The median of maternal serum AFP from 15 to 17 weeks of gestation was 43.4, 62.6 and 72.5 ng/ml. Three fetuses with chromosomal anomalies were diagnosed; trisomy 21, 4p trisomy, and trisomy 18 (trisomy 18 was in one fetus of a twin pregnancy; the other fetus was normal). Maternal serum AFP levels were, 0.41, 0.49 and 1.30 MOM. Maternal serum AFP less than 0.5 MOM in normal pregnancies was 1/205 (0.5%) and less than 0.6 MOM was 9/205 (4.4%). There was no relationship between maternal serum AFP and amniotic fluid AFP levels. Our results are in agreement with the majority of the results in the literature, showing that maternal serum AFP levels are lower in association with autosomal trisomy fetuses.

Isolation and characterization of a corticotropin-releasing hormone-like peptide from human placenta.

Immunoreactive CRH was detected in extracts of human term placentae [5.2 +/- 0.8 (+/- SE) pmol/g wet wt; n = 9]. Molecular sieve chromatography revealed three size classes of immunoreactive CRH. The major species eluted with the Kav of synthetic rat CRH; the minor species had apparent mol wt (MW) of 18,000 and 8,000. A placental CRH-(1-41)-sized peptide was isolated by fractional acetone precipitation, molecular sieve chromatography, and sequential reverse phase high performance liquid chromatography steps. This peptide had the same chromatographic behavior as did rat CRH in all high performance liquid chromatographic isolation steps as well as the same UV absorbance to immunoreactive CRH ratio after the final purification step. Purified placental CRH stimulated ACTH release from anterior pituitary tissue in a dose-dependent manner and was equipotent with synthetic rat CRH. Partial sequencing indicated that 32 amino acids of this peptide are identical to those of rat and human CRH (sequence deduced from genomic sequence), and comparative peptide mapping with rat CRH provided further evidence that the placental CRH-like peptide is very homologous if not identical to CRH. The high mol wt placental CRH fractions also were partially purified by acetone precipitation, immune affinity chromatography, and gel filtration. Neither of these materials [big form (MW, 18,000) or intermediate form (MWr, 8,000)] stimulated ACTH release from rat pituitary tissue in vitro. Limited trypsin digestion of the highest MW CRH, followed by gel filtration analysis, resulted in conversion to the smaller [8,000 MW-sized and CRH-(1-41)-sized] forms. The detection of a CRH-like peptide in placenta together with our previous demonstration of plasma immunoreactive CRH in pregnant women suggest that the placenta synthesizes and secretes CRH into the maternal circulation.

Peptide histidine methionine may be a prolactin-releasing hormone in humans.

Peptide histidine isoleucine (PHI) was initially isolated from the porcine gastrointestinal tract and may be present in the brain. It has been suggested that PHI may be PRL-releasing hormone (PRH) because of its potent PRL-releasing activity and its existence in hypophysial portal plasma in rats. Vasoactive intestinal peptide and PHI are coded by the same gene, and human PHI has a C-terminal methionine instead of isoleucine [peptide histidine methionine (PHM)]. To investigate the possibility that PHM is a physiological PRH in humans, we measured the immunoreactive PHM concentration in human hypothalamic tissue and cerebrospinal fluid (CSF) using a specific RIA. We also examined in vivo the PRH activity of synthetic PHM. The human hypothalamus contained 19.3 +/- 6.2 (+/- SD; n = 5) pmol/hypothalamus, very similar to the content of GHRH or CRH. Immunoreactive PHM was also present in CSF; its levels in CSF were significantly lower in patients with prolactinomas than in control subjects. The CSF PHM levels in such patients increased after correction of hyperprolactinemia by long term bromocriptine therapy. The CSF PHM levels also were low in pregnant women. There was a significant negative correlation between plasma PRL and CSF PHM levels in all of these subjects. Gel filtration profiles of CSF extracts from normal subjects revealed two peaks of immunoreactive PHM: a high mol wt peak and one at the elution position of synthetic PHM. This profile resembled that of hyppothalamic extract. In contrast, only high mol wt material was detected in CSF from hyperprolactinemic subjects. Intravenous administration of synthetic PHM elicited a significant increase in plasma PRL in normal subjects; the responses to PHM were higher in women than in men. The presence of large amounts of immunoreactive PHM in the human hypothalamus suggests that PHM may participate in the regulation of anterior pituitary hormone secretion. Its specific PRL-releasing activity in vivo and the low CSF PHM levels of hyperprolactinemic subjects suggest that PHM may be a physiological PRH in humans.

Effects of androgen on 17 beta-estradiol production by cultured human granulosa cells.

In order to determine whether androgen acts solely as a substrate for aromatization or whether it also influences on the activity of aromatase enzyme, human granulosa cells were incubated in vitro with or without androgen. Although basal production of 17 beta-estradiol (E2) in cultured granulosa cells obtained from follicles about 26 hr after the initiation of the LH surge was restricted in small quantities, a marked increase in E2 production occurred in the presence of testosterone (T) (10(-6) M) as aromatizable substrate. The non-aromatizable androgen, 5 alpha-dihydrotestosterone (DHT) (10(-7) M, 10(-6) M), slightly enhanced E2 production and it did not inhibit T aromatization in these cells. By contrast, DHT did not increase E2 production in granulosa cells obtained from follicles 2-5 days before the LH surge. The results indicate that androgen can enhance the estrogen biosynthesis of granulosa cells obtained from follicles during the LH surge not only by acting as a substrate for aromatization but also by participating in some process of the estrogen synthesis. This effect of androgen was not clearly seen in granulosa cells obtained before the LH surge, suggesting that the response of granulosa cells to exogenous androgen varies with the stage of the cell differentiation.

The maternal serum cortisol levels after onset of labor.

We measured maternal cortisol levels after the onset of labor. Blood from 82 primiparas and 48 multiparas were collected 124 times and 60 times, respectively. When duration of labor was within 3 hr, there were no differences in cortisol levels between the primiparous (n = 11, 50.4 +/- 7.0 micrograms/100 ml, mean +/- S.E.) and multiparous (n = 14, 37.8 +/- 4.3 micrograms/100 ml). However, when duration of labor was from 3 to 6 hr, cortisol levels in the primiparas (n = 20, 59.7 +/- 5.1 micrograms/100 ml) were significantly (p less than 0.05) higher than those in the multiparas (n = 22, 46.8 +/- 2.9 micrograms/100 ml). In cases of duration of labor from 6 to 9, cortisol level of the primiparas (n = 24, 64.3 +/- 4.4 micrograms/100 ml) were also significantly (p less than 0.05) higher than those in multiparas (n = 12, 49.4 +/- 4.7 micrograms/100 ml). When duration of labor was more than 9 hr there was no significant difference in cortisol level between the primiparas and multiparas. Maternal cortisol level had a significant (p less than 0.01) negative correlation (n = 166, r = -0.243, Y = -0.09X + 30.47) with unconjugated estriol level. These data suggest that maternal cortisol levels after the onset of labor are slightly different between the primiparous and multiparous, and that maternal unconjugated estriol levels decrease owing to reduction of the feto-placental blood circulation accompanied with uterus contraction during labor.

Serum unconjugated estriol levels during spontaneous labor.

We measured maternal serum unconjugated estriol (SUE3) levels in 244 cases (218 cases with labor and 26 without labor) and investigated the relationships among several obstetrical factors and SUE3 levels. There was no significant difference in the SUE3 level between the group with labor and the group without labor. However, the SUE3 level decreased gradually with prolonged duration of labor in multipara. There were significant positive correlations between the SUE3 levels and birth weights (n = 82, r = 0.375, p less than 0.01) or placental weights (n = 82, r = 0.381, p less than 0.01) in the multipara with labor. The SUE3 levels of fetal distress cases (n = 30, 20.0 +/- 8.6 ng/ml) were significantly (p less than 0.05) lower than those without fetal distress (n = 188, 24.5 +/- 9.7 ng/ml). These data suggest that maternal SUE3 might have been affected with feto-placental function, even after the onset of labor SUE3 levels decrease with prolonged duration of labor.

Immunoreactive corticotropin-releasing hormone in human plasma during pregnancy, labor, and delivery.

We previously reported that immunoreactive corticotropin-releasing hormone (CRH) is present in human placenta and third trimester maternal plasma, and that such material is very similar to rat CRH and the predicted structure of human CRH. We suggested that maternal plasma immunoreactive CRH may be of placental origin. To further investigate this possibility, we measured plasma immunoreactive CRH in women during pregnancy, labor, and delivery and 1 and 2 h postpartum, and in nonpregnant women. Umbilical cord plasma and placental CRH concentrations were also measured. In the first trimester of pregnancy, the mean maternal plasma level was 5.9 +/- 1.0 pg (+/- SEM)/ml (n = 24), not significantly different from that in 10 nonpregnant women (5.8 +/- 0.8 pg/ml). Plasma CRH concentrations progressively increased during pregnancy (second trimester, 35.4 +/- 5.9 pg/ml (n = 39); early third trimester (28-34 weeks), 263 +/- 41 pg/ml (n = 14); late third trimester (35-40 weeks), 800 +/- 163 pg/ml (n = 20)]. There was a significant correlation between maternal plasma CRH levels and weeks of pregnancy. Plasma CRH concentrations were further elevated (2215 +/- 329 pg/ml; n = 9). During early labor, peaked at delivery (4409 +/- 591 pg/ml; n = 28), and declined rapidly after delivery [1 h postpartum, 1042 +/- (353 pg/ml (n = 13); 2 h postpartum, 346 +/- 91 pg/ml (n = 13)]. There was a significant correlation (r = 0.562; P less than 0.01) between matched maternal plasma and placental CRH concentrations. The mean umbilical cord plasma CRH level (50.6 +/- 6.1 pg/ml; n = 28) was much lower than that in the mother at the time of delivery. Umbilical venous plasma CRH levels were significantly greater than those in simultaneously obtained umbilical arterial plasma (70.8 +/- 11.3 and 41.8 +/- 4.9 pg/ml, respectively; n = 11). There was a significant correlation (r = 0.384; P less than 0.05) between maternal and fetal CRH concentrations. Gel filtration of plasma obtained from women during the third trimester, at delivery, and early postpartum and placental extracts revealed two major peaks of immunoreactive CRH: a high mol wt peak and one at the elution position of rat CRH. In contrast, only rat CRH-sized material was detected in plasma from nonpregnant women and umbilical cord plasma. Maternal plasma immunoreactive CRH-sized material stimulated ACTH release from anterior pituitary tissue in a dose-dependent manner and was equipotent with rat CRH.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum cortisol levels in pregnancy induced hypertension patients.

We measured the serum cortisol levels in 15 normal and 8 pregnancy induced hypertension (PIH) primigravidas. The normal pregnancy had a significant (p less than 0.05) higher cortisol level than that of PIH patient. Especially, 4 severe PIH patients had a significantly (p less than 0.05) lower cortisol level. The lower maternal cortisol level of PIH patients became more significant with the severity of clinical symptoms of PIH. After the onset of labor, the cortisol levels of PIH patients did not elevate compared with normal pregnancy. These data suggest that in the PIH patient the reactivity of the adrenal cortex to adrenocorticotropic hormone (ACTH) may be blunted or the cortisol production in the adrenal cortex may be decreased by the tissue circulation insufficiency due to PIH.

Human beta-endorphin and beta-lipotropin levels in maternal and fetal plasma and amniotic fluid.

We measured beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) levels in human maternal and fetal plasma and amniotic fluid, simultaneously. It appeared evident that maternal circulating levels of beta-EP (n = 11, 163.9 +/- 12.9 pg/ml, mean +/- S.E.) and beta-LPH (n = 11, 413.0 +/- 25.9 pg/ml) at delivery were significantly (p less than 0.01) higher than those of maternal plasma at term (beta-EP; n = 4, 18.3 +/- 2.1 pg/ml, beta-LPH; 213.4 +/- 24.3 pg/ml) and those of amniotic fluid (beta-EP; n = 5, 8.5 +/- 1.2 pg/ml, beta-LPH; 215.1 +/- 44.9 pg/ml). Fetal beta-EP levels (n = 11, 79.1 +/- 5.8 pg/ml) were significantly (p less than 0.01) higher than those of amniotic fluid. These data suggest that the origin of amniotic fluid beta-EP may be an increased synthesis in the maternal and fetal pituitary gland but not in the placenta.

[TBG, TSH and thyroid hormones in fetus].

In this study, we measured cord serum thyroxine (T4), triiodothyronine (T3), reverse T3 (rT3), thyroxine binding globulin (TBG) and thyroid-stimulating hormone (TSH) in 37 fetuses (29-42 gestational weeks). The mean cord serum TBG was 18.2 +/- 3.2 mg/dl (mean +/- S.E., n = 37) and there was no correlation between cord serum TBG levels and gestational weeks. The cord serum T3 levels increased with advancing gestational weeks. On the other hand, cord serum rT3 levels decreased with advancing gestational weeks. There was a significant positive correlation between the TBG and T4 levels after 32 gestational weeks (n = 34, r = 0.545, p less than 0.001), and between the TBG and T3 levels (n = 36, r = 0.65, p less than 0.001). There was a significant positive correlation between the TBG and T3 levels after 37 gestational weeks (n = 24, r = 0.43, p less than 0.05). The cord serum TSH levels had a significant difference (p less than 0.05) between preterm fetus (n = 11, 12.8 +/- 2.2 mU/ml, mean +/- S.E.) and term fetus (n = 25, 8.2 +/- 0.8 mU/ml). The T4/TSH ratio in the preterm fetus (0.65 +/- 0.01) was significantly smaller (p less than 0.001) than that of term fetus (1.60 +/- 0.16). These results suggest that thyroid hormones are closely related with TBG in fetus and the sensitivity of the thyroid gland to TSH may increase with advancing gestational weeks.

[Studies on the alteration of the unconjugated estriol level of the maternal vein after the onset of labor].

We measured maternal venous unconjugated estriol (UE3) levels in 244 cases (218 cases with labor and 26 without labor). We investigated the relationships between several obstetrical factors and UE3 levels. There was no significant difference between the group with labor and the group without labor. However, in multipara, the UE3 level fell gradually with prolonged duration of labor. There were significant positive correlations between the UE3 levels and birth weights (n = 82, r = 0.375, p less than 0.001), and placental weights (n = 82, r = 0.381, p less than 0.001) in multipara with labor. There was no significant difference according to sex between the UE3 levels of a mother carrying a male or female fetus. The UE3 levels of fetal distress cases (n = 30, mean +/- S.E. 20.0 +/- 8.6 ng/ml) were significantly (p less than 0.02) lower than those without fetal distress (n = 188, 24.5 +/- 9.7 ng/ml). These data suggest that after the onset of labor, maternal venous UE3 has some relationship to feto-placental function.

[Amniotic fluid 3,3',5'-triiodothyronine (reverse T3)].

RT3(3,3',5'-triiodothyronine) levels in amniotic fluid and T4(thyroxine), T3(triiodothyronine), rT3 and TSH(thyroid-stimulating hormone) levels in maternal and cord serum were determined simultaneously by RIA. We also determined the activities of the monodeiodination of thyroxine to rT3 in placentas. Amniotic fluid rT3 and cord serum rT3 levels decreased, but T4, T3 and TSH levels increased with advancing gestational age. The activities of the monodeiodination in placentas decreased rapidly from midgestation, preterm to term. In maternal hyperthyroidism, amniotic fluid rT3 levels were markedly elevated. Moreover, there were significant positive correlations between amniotic fluid rT3 and maternal serum rT3 (r = 0.756, p less than 0.001, n = 26) and T4(r = 0.509, p less than 0.01, n = 26) in the normal 3rd trimester. We found significant correlations between amniotic fluid rT3 and fetal thyroid function as well as the activity of the monodeiodination in placenta after 17 weeks' gestation. But we couldn't find any such correlations in the 3rd trimester. These data suggest that the amniotic fluid rT3 in the 3rd trimester was affected by maternal thyroid function as well as fetal thyroid function and the activity of the monodeiodination in placenta.

Human placental thyroxine inner ring monodeiodinase in complicated pregnancy.

Production of rT3 from T4 in the placenta were measured in four patients with induced abortion, in three patients with spontaneous abortion, in 19 patients with various complications of pregnancy including Graves' disease, and in 18 normal pregnancies. The placentas, obtained at delivery, were homogenized and centrifuged at 800 X g. Supernatants (1 mg protein) were incubated with 1 microgram of stable T4 and 50 mmol/L dithiothreitol at 37 degrees C for 60 minutes. The generated rT3 was measured by radioimmunoassay (RIA). In patients who delivered at 38 to 41 weeks with complicated pregnancy, the net placental rT3 production from T4 was 7.3 +/- 2.5 ng/tube, which was not significantly different from that obtained in normal pregnancy (8.5 +/- 2.4) at an equivalent gestational age. In patients with abortions, the net placental rT3 generation from T4 was very high, and there was a significant negative correlation between the net placental rT3 production from T4 and gestational age. These results indicate that the net placental rT3 production from T4 is not affected by complications of pregnancy, but shows a significant change with the progress of gestation.

Serum cortisol levels in maternal venous, umbilical arterial and umbilical venous blood at delivery in the cases of fetal distress.

We measured maternal venous (MV), umbilical arterial (UA) and umbilical venous (UV) cortisol levels in 180 term pregnancies to investigate the changes of these hormone levels in the cases of fetal distress and neonatal asphyxia. The cortisol levels in UA and UV blood in the fetal distress group were significantly higher than those in the non-fetal distress group among spontaneous vaginal delivery cases. There were significant positive correlations among the cortisol levels in MV and UA, MV and UV, and UA and UV blood, respectively. These data suggest that in the case of fetal distress or neonatal asphyxia, mother and fetus have responded independently to the stress of delivery, and that maternal cortisol might not strongly affect the fetal cortisol secretion.

Simultaneous and serial measurement of serum levels of human placental lactogen, beta-human chorionic gonadotropin and unconjugated estriol levels in pregnant women.

Serum levels of human placental lactogen (hPL), beta-human chorionic gonadotropin (beta-hCG) and unconjugated estriol (E3) were measured simultaneously and serially in regular menstrual late pregnant women (155 samples) by radioimmunoassay. The peak of beta-hCG level was shown at 37 weeks' gestation. After that, there was a moderate decline of the beta-hCG level. Serum hPL showed the peak at 30 weeks' gestation. The level of unconjugated E3 rose toward 41 weeks' gestation. In the 155 samples, there were significant positive correlations among these hormone levels. Also, there were highly significant positive correlations between placental weight and these three hormone levels. Only unconjugated E3 level which was obtained within a week before the onset of labor had a significant positive correlation with birth weight. These data suggest that even in late pregnancy, maternal beta-hCG makes a peak and may change parallel with hPL and unconjugated E3. Only the unconjugated E3 level may be affected by fetal growth.