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Biomedical subjects

L Cedard

Publications and source records attributed to L Cedard.

At least 73 records · Page 4Linked to original sources
PubMed1981

Distribution, quantification and biological activity of messenger RNA coding for human chorionic somatomammotropin during normal pregnancy.

Synthesis of hCS by RNA fractions from human placentas obtained at different stages of pregnancy was estimated either by immunological or electrophoretical methods in wheat-germ and reticulocyte cell-free systems. hCS synthesis is preferentially associated with polyribosomes bound to the membrane of the endoplasmic reticulum, as is assumed for a secreted protein. In both translational systems we determined only one precursor form of this hormone of a molecular weight near 24 000. Full-term placentas synthesize hCS as the major protein. This conveniently allowed us to isolate the messenger RNA coding for the hormone and to synthesize a specific hCS complementary DNA which we used as a probe for quantifying sequences of RNA coding for hCS during pregnancy. In placentas from first-trimester pregnancy, the concentration of hCS mRNA was 4 times less than in the full-term organs, and the hCS synthesis per microgram of RNA added into the translational medium was diminished in the same order of magnitude. In placentas from second-trimester pregnancy, the concentration of hCS mRNA was similar to that obtained at term, and in vitro the hCS synthesis per microgram of translated RNA was also similar to that observed at the end of pregnancy. However, the hCS mRNA content per placenta from mid-term pregnancy was much lower than from full-term gestation. We established a good parallelism, as pregnancy progressed, between the hCS mRNA content, its capacity of hCS synthesis in vitro and the maternal plasma hCS level, indicating that hCS production is controlled essentially by the biological active mass of the placenta.

DNA↗
PubMed1981

DHEA-S-loading test in cases of intrauterine growth retardation: relationship between the pattern of the maternal plasma metabolites and the fetoplacental dysfunction.

Dehydroepiandrosterone sulfate loading tests (DLT) have been performed in 17 cases of clinically suspected intrauterine fetal growth retardation. At birth, 9 babies had adequate birth weights for gestational age (AGA) and 8 infants were small for gestational age (SGA). In both groups, plasma levels of dehydroepiandrosterone sulfate (DHEA-S), unconjugated DHEA, delta4-adrostenedione (delta4-A), testosterone (T), unconjugated estrone (E1) and estradiol (E2) were measured seven times from 15 min to 4 h after the intravenous injection of 50 mg DHEA-S. Several differences appear between the AGA group and the SGA group: (1) in the latter group, the rate of disappearance of the injected DHEA-S is decreased; (2) plasma levels of delta4-A and T are significantly increased and remain elevated for 2-3 h, whereas in the AGA group these values are increased only for a short period of time just after the injection. E1 and E2 patterns are similar in both groups. It has previously been demonstrated that an impaired response to DLT reflects a reduced uteroplacental blood flow. In addition, our results suggests a concomitant impairment of the aromatizing activity which reduces the placental metabolization of neutral steroids to estrogens.

Androstenedione↗
PubMed1980

Steroid concentrations and delta 5, 3 beta-hydroxysteroid dehydrogenase activity in human placenta. Comparison between elective cesarean section and spontaneous vaginal delivery.

The level of delta 5, 3 beta-hydroxysteroid dehydrogenase (delta 5, 3 beta-HSDH) was measured in the mitochondrial and microsomal fractions of the human term placenta. The capability of the placenta to transform pregnenolone to progesterone was found to be significantly higher after spontaneous vaginal delivery than after elective cesarean section (p < 0.001). There was a significant rise in the placental concentration of estrone occurring at the time of parturition (p < 0.01). The placental concentration of estradiol-17 beta was also greater after than before parturition but the diffference was not statistically significant. Conversely to the estrogen concentration, no difference existed in the progesterone concentration between the two groups of placentas. The significance of these findings is discussed in relation to the parturition process.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

Placental sulfatase deficiency: clinical and biochemical study of 16 cases.

Clinical and biochemical data of 16 typical cases of placental sulfatase deficiency have been observed. In vivo loading tests with DHA-S allowed us to make a prenatal diagnosis. In vitro experiments gave confirmation, showing zero or virtually zero placental sulfatase activity towards delta 5P or DHA sulfates Aromatase activities, when tested, were normal or more often less than standard values, the latter showing themselves rather large individual variations. All pregnancies were associated with the delivery of male neonates in good health but 3. The 15 living babies have been developing normally since then. These results, together with those reported in the literature, suggest that placental sulfatase deficiency is under control of an X-linked recessive character, this being supported by the recent observation of such a disorder in two sisters simultaneously pregnant. As to the high frequency problem of cesarian section, pointed out by several authors, we cannot conclude, from our own observations, that the defect has an obvious influence on the good outcome of labor, as 10 out of the 16 women delivered vaginally near term.

Aromatase↗
PubMed1980

Exogenous DHA-S half-life: a good index of intrauterine growth retardation.

E3 and HPL hormone levels in maternal plasma are predictable of adequate birth weight for gestation age (AGA) when their values are higher than the mean for the term of pregnancy, but low values correspond to 'small-for-gestation-age' (SGA) infants in about 50% of the cases only. DHA-S (50 mg i.v.) half-life (DHS-S t 1/2) was calculated by least-squares analysis on the plot of log DHA-S concentration versus time at several intervals. 102 tests were performed in pregnant women between 30 and 41 weeks of amenorrhea (43 control, 59 suspicion of IUGR among them 29 AGA and 20 SGA). The difference between DHA-S t 1/2 is statistically highly significant (p < 0.001) between SGA and the other groups. Evaluation of birth weight was correct in 95 cases (76 normal babies < 4.29 h, and 19 SGA greater than or equal to 4.29 h, showed false-positive results in 6 cases, and false-negative in 1 case. This test has now been included in our routine practice for further evaluation of intrauterine growth retardation.

Birth Weight↗
PubMed1980

Gonado-pituitary relationships in the fetal mouse at various times during sexual differentiation.

Levels of testosterone in plasma and concentrations of LH in both plasma and pituitary glands of fetal mice aged 14, 16 and 18 days were measured by radioimmunoassays in a representative number of fetuses. During this period levels of testosterone in the plasma of male mice were significantly higher than those in the females. Levels of testosterone in plasma of male mice increased from day 14 to day 16 of gestation and decreased on day 1 before parturition. Plasma concentrations of LH remained undetectable in male and female fetuses until day 16 of gestation. levels of LH rose slightly in both sexes in later gestation, but still remained significantly lower in the plasma of male fetuses on days 17-18. In contrast, higher but not significantly different concentrations of LH were observed in pituitary glands from days 14 to 18 in male compared with female mice. These observations suggest that the high levels of testosterone in the plasma of male fetal mice might be responsible for feedback inhibition of LH secretion during the last days of gestation.

Animals↗
PubMed1980

[Change test with DHEA-S in vivo and in vitro. Hypotrophy and utero-placental blood flow (author's transl)].

Using the method of Cedard and al., we perfused 18 placentas of women in which DHEA-S loading test has been performed during pregnancy. For each placenta, we measured the increase of estrogens in the perfusate (E1 + E2) 15 minutes after the injection of 10 mg of DHEA-S, and we calculated the half-life of the precursor in the system in well-standardized conditions. The comparison between: 1. Placentas of small for date babies and normal ones. 2. The increase of estrogens and the half-life of DHEA-S measured during pregnancy on the one hand and the same data obtained from the perfusion on the other, leads us to conclude that the capacity of the placenta to metabolize DHEA-S into estrogens is not diminished in small-for-date babies. The factor which modifies the response of the DHEA-S loading test in poor intrauterine growth seems to be due to a reduction of utero-placental blood flow.

Dehydroepiandrosterone↗
PubMed1978

Steroid concentrations in human myometrial and placental tissues at week 39 of pregnancy.

Endogenous levels of P, E1, and E2 were determined by radioimmunoassay in human myometrium and placenta at week 39 of pregnancy. In the myometrium, P and estrogens were higher in the inner layer near the placenta than in other zones. Higher E2/P ratios were found in placental sites. A large difference in the E2/P ratios was observed between placenta and corresponding adjacent myometrial area, indicating an easier diffusion of E2 from the site of its production.

Estradiol↗
PubMed1978

[Leydig cell tumours of the testis. Two cases presenting opposing sexual features : gynaecomastia, precocious virilisation, and revealed by study in vitro of aromatisation activity].

Two Leydig cell tumours presented with changes in sexual characteristics. The first patient was a child with precocious puberty whilst the second was that of an adult with recurrent gynaecomastia. Histochemical examination in vitro of tumour tissue from the second patient made it possible to explain the synthesis of oestrogens by a primary tissue destined to an essentially androgenic activity.

Adolescent↗
PubMed1978

The lecithin/sphingomyelin ratio in 132 insulin-dependent diabetic pregnancies.

A total of 228 determinations of L/S ratios were performed in 132 insulin-dependent diabetic pregnancies. A declining L/S ratio was observed in 6 per cent of the cases without adverse effects on the fetus. No significant difference in the percentage of mature L/S ratios by weeks of pregnancy was found in the different classes of diabetes. An immature L/S ratio was associated with a significant increase of low Apgar scores. At each stage of pregnancy, there was no significant difference in the percentage of mature L/S ratios according to the sex of the baby nor according to the presence or absence of polyhydramnios. Among the five infants with HMD two had a mature L/S ratio within 2 days of birth. This represents 3 per cent incidence of false-positive results. Despite this finding, we feel that the determination of L/S ratio is a useful advance in the management of diabetic pregnancies.

Amniotic Fluid↗