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PubMed1982

Partial characterization of mouse placental lactogen.

Serum, placental, extracts, and placental incubation medium from 12- and 17-day-pregnant mice were fractionated by gel exclusion chromatography on Sephadex G-100. The eluates were monitored for activity by a radioreceptor assay (RRA) for lactogenic hormones that detects placental lactogen (PL) and PRL. RRA activity in serum and placental extracts and incubation medium from both days of gestation eluted in two peaks, the first emerging in the void volume (Vo) and the second with an elution volume (Ve) to Vo ratio of 1.96, which was similar to the Ve to Vo ratio of a human PL marker. Fractions in the second peak stimulated casein synthesis in mouse mammary gland explants. The RRA activity of the eluates was not due to the presence of PRL, as determined by RIA, and therefore the activity in the second peak was identified as monomeric PL. Electrophoresis of mouse placental extracts and incubation medium from both days 12 and 17 of gestation on 10% polyacrylamide gels showed only one band of RRA activity (Rf = 0.22). The present results show there are no differences between the elution profiles on Sephadex G-100 and the electrophoretic mobilities of PL from serum, placental extracts, and placental incubation media from days 12 and 17 of pregnancy in mice.

Animals↗
PubMed1989

[Human placental oxytocin and its increase by prostaglandin E2 and F2 alpha].

To investigate the physiological roles of human placental oxytocin (OT)-like substance, partial purification of human placental extract and placental tissue culture were carried out. 1. Both oxytocic immunoreaction in our own specific radioimmunoassay and bioaction on rat uterine contraction were observed in the larger (MW greater than or equal to 5,000) and the smaller molecular part (MW not equal to 1,000) in partially purified placental extracts by gel-filtration using Sephadex G-25. 2. Prostaglandin E2 and F2 alpha enhanced the immunoreactive OT in the cultured human term placental tissue at doses of 1-100 micrograms/ml. These findings are considered to be significant in basic studies of human placental OT-like substance.

Animals↗
PubMed2004

Anesthesia for obstetric patients with Gaucher disease: survey and review.

Pregnancy and delivery in patients with non-neuronopathic Gaucher disease, whether treated with enzyme replacement or untreated, are usually uncomplicated. Various factors may influence mode of delivery, vaginal or cesarean section, as well as type of anesthesia, general or regional, used during delivery. This retrospective review was intended to highlight some of the practical issues relating to obstetric anesthetic management, based on a review of the literature and experiences from a large referral clinic for Gaucher disease. In the past decade, there were 16 deliveries in 11 women in our institution. There were five normal vaginal deliveries, two vacuum extractions, one placental extraction, and eight cesarean sections. Platelet counts were 27-215 x 10(9)/L. Two spontaneous deliveries and one vacuum extraction were performed under epidural anesthesia; two other women having vaginal deliveries and one vacuum extraction were given i.v. analgesia; the fifth was given i.v. patient-controlled analgesia. The placental extraction was performed under general anesthesia. Seven of the women having cesarean deliveries received spinal anesthesia; the breech presentation required general anesthesia. There were no anesthesia-related side effects or complications, although there were some instances of post-partum bleeding irrespective of enzyme therapy. Gaucher disease affects multiple organs and can be a challenge to the anesthesiologist. Based on this survey we suggest that anesthetic management requires particular attention to hematological parameters before delivery. A multidisciplinary approach and extensive communication among obstetrician, hematologist and anesthesiologist is required to anticipate the possibility of post-partum hemorrhage, and preclude skeletal damage.

Adult↗
PubMed1976

Binding of mouse choriomammotropin to prolactin receptors in the mouse mammary gland.

The interaction between mouse choriomammotropin and mouse mammary glands was examined by radioreceptor assays using ovine prolactin (NIH-P-S9) iodinated by lactoperoxidase as a tracer. Mouse pituitary extracts and placental extracts were subjected to 10% acrylamide gel electrophoresis. Gels were cut into 2-mm segments after electrophoresis, and stored in 1 ml 0.05 M phosphate buffer (pH 7.4) containing 0.05 M NaCl overnight for elution. Lactating mammary tissues from D strain mice were incubated for 120 min in 1 ml Medium 199 containing 6 ng of 125I-prolactin and 0.1 ml of each eluate. Pituitary extracts displaced 125I-prolactin only at the position which coincides with the prolactin band. Displacement was observed at two positions of the gel when placental extracts were used. Relative mobilities (Rm) were 0.21 and 0.71, respectively. The slowly migrating component of choriomammotropin inhibited the binding of 125-I-prolactin more strongly that the rapidly migrating one. Neither of them was identified as a distinct band in stained gels. The molecular weight of ovine prolactin, mouse pituitary prolactin and the slowly migrating component of mouse choriomammotropin was estimated to be 23000 using disc electrophoresis but the ion charges of these hormones were considerably different.

Animals↗
PubMed1993

On-line recognition and quantitation of coeluting hypoxanthine and guanine in reversed-phase high-performance liquid chromatography of placental tissue extracts: photodiode-array detection and spectral analysis of coeluting peaks.

In a reversed-phase HPLC method, optimized for resolution and quantitation of nucleosides and nucleobases in human term placental extracts, guanine coeluted with hypoxanthine. Three numerical techniques that treat spectral data generated by photodiode-array detection to yield indices of peak purity were compared for sensitivity of on-line recognition of overlapped guanine and hypoxanthine peaks in chromatograms of 7.0 microM hypoxanthine containing 0.075-0.54 microM guanine. These techniques were purity parameter, the average wavelength of a peak spectrum (lambda w), peak area ratio, and peak absorbance ratio. Purity parameter of a 7.0 microM hypoxanthine peak containing 1% guanine was significantly different from that of pure hypoxanthine (P < 0.01); peak area and peak absorption ratios were four and seven times, respectively, less sensitive than purity parameter. In chromatograms of human term placental extracts, purity parameter values generated on-line signalled the presence of guanine in hypoxanthine peaks. Quantitation of coeluting hypoxanthine and guanine was performed on-line from dual-wavelength detection at 249 and 278 nm via calibration curves for both analytes at these wavelengths. Hypoxanthine and guanine concentrations in seven samples from five human term placentas were 41-161 and 3-76 nmol/g, respectively. These findings demonstrate that on-line signalling of hypoxanthine and guanine coelution is achieved by purity parameter, area ratio, and absorbance ratio, that purity parameter is the most sensitive index of coelution, and that quantitation of the coeluting analytes can be performed on-line. These approaches should be applicable to recognition and quantitation of coeluting analytes in chromatograms of mixtures of nucleosides and nucleobases such as occur in extracts of other tissues.

Chromatography, High Pressure Liquid↗
PubMed1993

Identification and preliminary characterization of luteotropic activity in the rabbit placenta.

The corpus luteum of the rabbit requires estradiol (E2) and the conceptus to maintain progesterone (P4) during the second half of pregnancy. The factor produced by the fetal placenta that is responsible for maintaining P4 production has not yet been identified. Therefore, the goal of these experiments was to determine whether the rabbit placenta contained luteotropic activity and to begin preliminary characterization of this factor. A bioassay system utilizing corpora lutea explants incubated with placental extracts and other treatments was developed and validated. Neither pooled placental extracts (200 micrograms) nor E2 alone affected P4 production (p > 0.05). However, the combination of placental extracts plus E2 significantly stimulated P4 production approximately 1.5-fold (p < 0.05). Skeletal muscle (200 micrograms) + E2 also had no effect on P4 production, indicating that the effect of placental extracts was tissue-specific. Carboxymethyl-cellulose ion-exchange chromatography of placental extracts yielded four separate fractions, which were examined individually at three doses for activity in the bioassay system. The first and most acidic fraction (Fraction 1) significantly stimulated P4 production at 10 and 100 micrograms when incubated in combination with E2 (p < 0.05). Both heat and trypsin treatment abolished the ability of placental Fraction 1 to stimulate P4 production in the presence of E2. Size fractionation of Fraction 1 using dialysis membranes with 3500, 6000-8000, and 12,000-14,000 molecular weight cutoff points had no effect on bioactivity of Fraction 1. These results indicate that the rabbit placenta contains a potential luteotropin with the characteristics of an acidic, heat-sensitive protein greater than 12,000-14,000 in molecular weight.

Animals↗
PubMed1998

Contribution of type II phospholipase A2 to in vitro phospholipase A2 enzymatic activity in human term placenta.

Although phospholipase A2 (PLA2) enzymatic activities have been implicated in the regulation of phospholipid metabolism and eicosanoid formation in human gestational tissues, the role and contribution made by individual PLA2 isozymes has not been established. The aim of this study, therefore, was to determine the contribution made by Type II PLA2 to PLA2 enzymatic activity present in human term placenta. The experimental paradigm used to establish the contribution made by Type II PLA2 to total in vitro PLA2 enzymatic activity present in placental extracts was to remove Type II PLA2 by immunoaffinity extraction and then to quantify residual PLA2 enzymatic activity. Before immunoaffinity extraction, Type II PLA2 immunoactivity and total PLA2 enzymatic activity present in placental extracts averaged 28.0 +/- 10.0 ng/mg protein and 1040 +/- 367 pmol/h per mg protein (n = 3) respectively. After solid-phase immunoaffinity batch extraction of placental extracts, immunoreactive Type II PLA2 was not detectable by ELISA, and PLA2 enzymatic activity was decreased by 82 +/- 1% (P < 0.001). Residual (i.e. non-Type II) PLA2 enzymatic activity was further characterised by Western blot analysis and enzyme activity assay. The data obtained are consistent with a contribution by both cytosolic PLA2 and other secretory PLA2 isozymes (i.e. non-Type II) to residual PLA2 enzymatic activity. The results obtained in this study support the conclusion that Type II PLA2 is quantitatively the primary PLA2 isozyme that contributes to in vitro PLA2 enzymatic activity present in extracts of human term placenta, accounting for at least 80% of total activity. These data further support the involvement of this extracellularly active isozyme in the regulation of placental phospholipid metabolism and eicosanoid formation during late gestation.

Blotting, Western↗
PubMed1979

Thyrotropin-releasing hormone activity in the human placenta.

TRH immunological and biological activities were found in extracts of human placentas. Eight term placentas delivered by cesarean section were extracted with 2 N acetic acid, followed by glacial acetic acid. Lyophilized samples were resuspended in phosphate-buffered saline. TRH activity, identified in each placental extract by specific RIA, averaged 19.8 +/- 3.3 pg/mg protein. TRH in the placental extracts was similar to synthetic TRH by four criteria. 1) Serial dilutions of placental extracts defined an immunoassay inhibition curve with a slope (-1.93) identical to synthetic TRH (-1.88). 2) When placental extract or synthetic TRH was chromatographed on Sephadex G-10, TRH immunoreactivity was found in similar fractions of the eluate. 3) Both placental extract and synthetic TRH stimulated TSH release from rat pituitaries in vitro. 4) Human serum degraded placental extract and synthetic TRH in a qualitatively similar manner. Placental minces did not accumulate exogenous [3H]TRH, suggesting that the placental TRH may originate endogenously.

Animals↗
PubMed1989

Fetal aortic cholesterol concentration and metabolism: relationship to plasma cholesterol and potential role of placental factors.

The relationship of fetal plasma cholesterol levels to aortic free and esterified cholesterol concentration was determined in the rabbit during gestation. Plasma cholesterol levels (mg/dl) in early fetuses were markedly high and decreased at term. While aortic free cholesterol content increased with fetal age, cholesteryl ester concentration did not change significantly and no pathological accumulation was evident. This occurred despite high fetal aortic cholesterol esterification activity noted in earlier studies. We evaluated the potential effect of rabbit placental extracts on lipid metabolism and cellular proliferation in fetal aortic explants to explore the role of placental factors in affecting lipid metabolism. Labeled [14C]oleate and [3H]thymidine were used to investigate the rates of incorporation of (a) oleate into lipids, and (b) thymidine into DNA, respectively. Placental extracts at term (but not from 22 days gestation) significantly decreased oleate incorporation (P less than 0.05) into cholesteryl esters, phospholipids and diglycerides. This effect of placental extracts was noted both in absence or presence of serum in the culture medium, and was predominantly found in fraction of Mr greater than 100,000. [3H]Thymidine incorporation (dpm/g protein) into DNA was significantly decreased (P less than 0.01) by placental extracts. These studies suggest that placental extracts contain factor(s) influencing fetal aortic lipid metabolism in culture.

Animals↗
PubMed1984

Adrenocorticotropic activity of an extract from sheep placental tissue at term.

We have performed experiments to determine possible adrenocorticotropic activity in placental tissue of a sheep at term. The placental tissue was homogenized and extracted with 0.1 mmol/L of ammonium bicarbonate. The adrenocorticotropic activity of the term placental extract was compared to that of the vehicle (saline solution) and synthetic adrenocorticotropic hormone (ACTH). A single bolus injection of term placental extract had no significant effect on the plasma concentration of cortisol or progesterone. In a separate protocol, a bolus injection of ACTH was administered before and after a 48-hour continuous infusion of term placental extract, ACTH, or saline solution. The infusion of term placental extract or ACTH caused a significant increase in the basal cortisol and progesterone concentrations and a greater progesterone response following the second ACTH bolus. In vitro, the isolated adrenal cells from the term placental extract- and ACTH-infused animals showed a significantly greater ability to produce cortisol in the presence of exogenous substrate and ACTH. We concluded that placental tissue from sheep at term contains a substance which, when infused in vivo, has a corticotropic effect on the adrenal glands.

Adrenal Glands↗
PubMed1990

Attempts for identification of a chorionic gonadotrophin-like bioactivity in the rat placenta which stimulates the testosterone secretion of the fetal testis in vitro.

The bioactivity of rat placental extracts was evaluated using a fetal rat testis testosterone (FRTT) bioassay. It is based on the measurement of the increase in testosterone secreted in vitro by testes from 18.5-day-old fetuses in response to the addition of placental extracts. Placentas obtained on days 11.5, 12.5, 13.5, 14.5, 15.5, 17.5 and 19.5 and homogenized with a Potter homogenizer (1 placenta per ml incubation medium), increased the secretion of testosterone by 460, 690, 500, 300, 220, 200 and 170%, respectively. These extracts showed a high proteolytic activity capable of suppressing the bioactivity of 0.8 ng/ml LH added prior to the extraction procedure. However, the bioactivity of the placental extracts did not increase after inhibiting placental proteases by the addition of benzamidine. Heat treatment did not decrease the bioactivity of placental extracts obtained without inhibition of proteases. Ultrafiltration of the placental extracts obtained with inhibition of the proteases showed that most of the bioactivity was dialyzable. The levels of bioactive material with molecular weights greater than 10,000 were very low (0.06 ng LH equivalent/placenta on day 12.5 and less than 0.02 ng LH equivalent/placenta on day 14.5). These results suggest that rat placental bioactivity as measured with the FRTT bioassay is due, for the most part, to steroid precursors of testosterone and, for a very small part, to an LH/chorionic gonadotrophin (CG)-like molecule. Furthermore, after day 14.5, the placental LH/CG-like bioactivity, if it exists, is synthesized in too low levels to be able to control the testicular activity in the rat fetus.

Animals↗
PubMed1988

Evidence for a novel parathyroid hormone-related protein in fetal lamb parathyroid glands and sheep placenta: comparisons with a similar protein implicated in humoral hypercalcaemia of malignancy.

Parathyroid hormone (PTH)-like bioactivity, assayed as adenylate cyclase response in UMR 106-01 osteogenic sarcoma cells, was present in extracts of sheep fetal and maternal parathyroid glands and placenta. Preincubation of extracts with PTH(1-34) antiserum inhibited approximately 40% of the bioactivity in fetal parathyroid extracts, 50% in maternal parathyroid extracts, but only 10% of the bioactivity in the placental extract. Partial purification of placental extracts by chromatography yielded fractions containing PTH-like bioactivity which were similar in behaviour to that of PTH-related protein (PTHrP) from a human lung cancer cell line (BEN). An antiserum against synthetic PTHrP(1-16) partially inhibited the bioactivity of the placental extract and synthetic PTHrP(1-34), but had no effect on the bioactivity of bovine PTH(1-34) or bovine PTH(1-84). The placental PTH-like bioactivity was higher in mid- than in late gestation. Fetal parathyroid glands contained the highest PTH-like bioactivity. Thyroparathyroidectomy of one fetal twin lamb in each of 16 ewes between 110 and 125 days of gestation resulted in decreases of the plasma calcium concentration and reversal of the placental calcium gradient that existed between the ewe and the intact fetus. Perfusion of the placenta of each twin in anaesthetized ewes was carried out sequentially with autologous fetal blood in the absence of the exsanguinated fetus. The plasma calcium concentration in the blood perfusing the placenta of each twin increased, but reached a plateau at a lower concentration in the perfusing blood of thyroparathyroidectomized fetuses than in that of the intact fetuses. Addition of extracts of fetal parathyroid glands or of partially purified PTHrP resulted in further increases in plasma calcium in the autologous blood perfusing the placentae of thyroparathyroidectomized fetuses, but addition of bovine PTH(1-84) or rat PTH(1-34) had no effect. The presence of this PTH-like protein in the fetal parathyroid gland and placenta may contribute to the relative hypercalcaemia of the fetal lamb. This protein, which is similar to PTHrP associated with humoral hypercalcaemia of malignancy, stimulates the placental calcium pump responsible for maintaining a relative fetal hypercalcaemia during gestation.

Animals↗
PubMed1989

Characterization of baboon pregnancy-specific beta 1-glycoprotein.

Immunostaining of baboon placental tissues with anti-human pregnancy-specific beta 1-glycoprotein (SPI) antibodies demonstrated that an SP1-like molecule was present in the syncytiotrophoblasts. Staining was observed on the membrane and in the cytoplasm, but the nucleus was devoid of any staining. Western blot analysis further demonstrated the presence of five protein species in baboon placental extract, whereas four protein bands were detected in human placental extract. Culture medium of baboon placental villi also contained five SP1-like molecules with sizes slightly different from those present in the placental extract. Amniotic fluid and culture medium of decidua basalis and chorioamniotic tissue contained lesser quantities and fewer species of SP1-like molecules. However, an 87 kDa band was present in all samples examined. Northern blot analysis of baboon placenta with a human placental SP1 cDNA probe demonstrated the presence of a 1.65 Kb band, whereas two hybridizing bands (1.65 Kb and 2.25 Kb) were present in human placenta. Southern blot analysis of baboon genomic DNA further demonstrated the presence of multiple bands hybridizing with a human placental SP1 cDNA probe. These results showed the presence in baboons of multiple genes encoding mRNAs and proteins highly similar to human placental SP1.

Animals↗
PubMed1985

Failure of injection of rat placental lactogen to inhibit prolactin in vivo.

In an attempt to demonstrate a negative feedback of rat placental lactogen (rPL) on prolactin secretion, pregnant rats were hysterectomized and injected intraperitoneally with placental extracts. Hysterectomy alone prolonged the incidence of nocturnal prolactin surges and injection of placental extracts did not alter this response. However, the absence of rPL in the serum following the injections indicated a primary reason why no inhibition was seen. Only when rPL was given intravenously was there detectable amounts found in the blood. The slow disappearance of rPL from the circulation following hysterectomy in Day 11 pregnant rats suggests that the lack of rPL in the blood following ip injection of placental extracts is not due to rapid clearance of rPL from blood. The failure to show a negative feedback of rPL on prolactin in vivo may be due primarily to the lack of appearance of rPL in the circulation following an ip injection of placental extracts.

Animals↗
PubMed1992

The stereoselective recognition of substrates by phosphoinositide kinases. Studies using synthetic stereoisomers of dipalmitoyl phosphatidylinositol.

Soluble phosphatidylinositol (PtdIns) 4- and 3-kinase activities were partially purified and characterized from human placental extracts. The placental PtdIns 4-kinase (type 3) has a Km for ATP of 460 microM and is kinetically different to a partially purified human erythrocyte, membrane-bound, PtdIns 4-kinase (type 2). These three inositol lipid kinases were then used to compare their substrate specificities against the four synthetic stereoisomers of dipalmitoyl PtdIns. Only the placental 4-kinase was influenced by the chirality of the glycerol moiety of PtdIns. However, neither of the 4-kinases was able to phosphorylate L-PtdIns and, therefore, these kinases have an absolute requirement for the inositol ring to be linked to the glyceryl backbone of the lipid through the D-1 position. Phosphoinositide 3-kinase, on the other hand, was found to phosphorylate both D- and L-PtdIns. While the 3-kinase phosphorylated exclusively the D-3 position of D-PtdIns, further analyses demonstrated that the same enzyme phosphorylated two sites on L-PtdIns, namely the D-6 and D-5 positions of the inositol ring. Some implications of these findings are discussed.

1-Phosphatidylinositol 4-Kinase↗
PubMed1993

Insulin-like growth factor (IGF)-I stimulates proliferation and migration of mouse ectoplacental cone cells, while IGF-II transforms them into trophoblastic giant cells in vitro.

We examined the effects of a 10.5-day placental extract and various growth factors (insulin-like growth factor [IGF]-1, IGF-II, epidermal growth factor [EGF], basic fibroblast growth factor [b-FGF], and transforming growth factor-alpha [TGF-alpha]) on proliferation, migration, and transformation of mouse ectoplacental cone (EPC) cells in vitro. Both the 10.5-day placental extract and IGF-I increased the surface area of the EPC cell colony and strongly stimulated the uptake of bromodeoxyuridine (Brd-U) as well as the migratory activity of EPC cells on the plastic culture dish. Such effects of 10.5-day placental extract were partly inhibited by the addiction of anti-IGF-I antibody. On the other hand, IGF-II did not significantly affect proliferation and migration of EPC cells, but increased the number of cells having a large nucleus (trophoblastic giant cells; TGCs) per EPC and enlarged the ploidy levels of EPC cells. Histochemical staining with succinyl wheat germ agglutinin (s-WGA), an in situ marker for secondary TGCs on Day 10.5 post coitum revealed that IGF-II or the placental extract induced the expression of s-WGA-binding glycoproteins in the TGCs in vitro. The effects of IGF-II or placental extracts were also inhibited by anti-IGF-II monoclonal antibody. No appreciable effect was found in the EPCs cultured with TGF-alpha, whereas b-FGF and EGF promoted migratory activity of the cells. The present study indicates that IGFs or IGF-like substances may be present in the mouse placenta, that IGF-I may promote the proliferation and migration of EPC cells, and that IGF-II may induce the transformation of EPC cells into TGCs in vitro.

Animals↗