Placenta. Supplement最新文献

{"title":"Differential responsiveness of cells of human amniotic epithelium to ferritin and 125I-prolactin in vitro.","authors":"J A McCoshen,&nbsp;S Chudasama,&nbsp;J E Tyson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Human amniotic epithelium has been found to consist of two cell types, known as dark and light cells, that are functionally different with respect to the passage of large molecules across the epithelium. Both cell types permit passage of ferritin intercellularly, whereas light cells incorporate this macromolecule. Dark cells impair the passage of 125I-PRL both inter- and intracellularly, whereas it is localized in light cells. In addition to a selectivity regarding the transmembrane passage of large molecules by the two cell types, we suggest that the osmoregulatory action of PRL on human amnion is restricted to the epithelial layer, and that its action may be mediated by light cells.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"33-47"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Presence of immunoreactive luteinizing hormone-releasing factor in hydatidiform mole as compared with normal human trophoblastic tissue.","authors":"R Osathanondh,&nbsp;K E Elkind-Hirsch","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Concentrations of luteinizing hormone-releasing factor (LRF) and human chorionic gonadotrophin (HCG) were measured by specific radioimmunoassay in homogenates of molar tissue evacuated from four patients at eight to 16 weeks of pregnancy (by menstrual dates), and in normal trophoblastic tissue of equivalent gestational age. In normal trophoblastic tissue HCG concentrations decreased, while LRF concentrations increased, with advancing gestational age. Molar tissue contained high quantities of HCG (2292 +/- 1415 s.e.(mean) iu/g wet weight vs 355 +/- 129 in the placenta) and very low, but consistently measureable, quantities of LRF (23.4 +/- 6.7 pg/g vs 12,808 +/- 2931 in the placenta). The significance of our finding of high HCG concentrations in the presence of low concentrations of LRF in neoplastic trophoblastic tissue is being further investigated.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"257-61"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17817613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of receptor-mediated low-density lipoprotein uptake and degradation in the regulation of progesterone biosynthesis and cholesterol metabolism by human trophoblasts.","authors":"C A Winkel,&nbsp;P C MacDonald,&nbsp;E R Simpson","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Dispersed human placental trophoblastic cells, maintained in primary culture, utilize principally cholesterol derived from low-density lipoprotein (LDL) for progesterone biosynthesis. The rate of secretion of progesterone by these cells increased (100 ng X mg-1 cell protein X 24 h-1 to 390 ng X mg-1 cell protein X 24 h-1) as the LDL concentration in the culture medium was increased (0 to 420 micrograms protein X ml-1). At an HDL-protein concentration of 1000 micrograms protein X ml-1, the rate of progesterone secretion by these cells was one-half that attained by cells maintained in medium containing LDL. The uptake of [125I]iodo-LDL by trophoblastic cells increased at [125I]iodo-LDL concentrations between 0 and 14 micrograms protein X ml-1 in the culture medium, was maximal by 5 to 6 h, and was diminished progressively as the concentration of non-radiolabelled LDL, but not HDL, was increased. Degradation of [125I]iodo-LDL increased as a function of the [125I]iodo-LDL concentration in the culture medium, was linear from 30 min to 32 h, was inhibited by the addition of choloroquine (40 mumol/1) to the culture medium; and was diminished progressively as the concentration of non-radiolabelled LDL, but not HDL, was increased. We observed a reduction in uptake and degradation of [125I]iodo-LDL by these cells as a function of the LDL concentration in the preincubation culture medium. Moreover, when the cells were preincubated with LDL for various times, a 90 per cent reduction in the rate of uptake and degradation of [125I]iodo-LDL was observed after 14 h. These findings are suggestive that trophoblastic cells are capable of down-regulating the number of LDL receptors on the cell surface. The incorporation of radiolabelled oleic acid into cholesteryl esters by these cells was linear for 6 h, increased as a function of the oleic acid concentration in the culture medium, and was stimulated when LDL was present in the culture medium. On the other hand, the synthesis of cholesteryl esters was inhibited half-maximally when the progesterone concentration in the culture medium was 20 mumol/1. Finally, the incorporation of [14C]acetate into cholesterol was inhibited as a function of the LDL concentration in the culture medium. Based on the results of these studies, our belief is that mechanism(s) have been elucidated to define the regulation of (1) progesterone biosynthesis; (2) de novo cholesterol synthesis; (3) intracellular cholesteryl ester storage; and (4) LDL uptake by normal human trophoblastic cells.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"133-43"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17367839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studies of the interaction between human transferrin and specific receptors on the trophoblast membrane.","authors":"R M Galbraith,&nbsp;P Werner,&nbsp;R R Kantor,&nbsp;G M Galbraith","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The concept of specific receptors for maternal transferrin on the human syncytiotrophoblast membrane has been generally accepted for many years, but definitive evidence of their existence has been established only recently. In this study, experiments were performed to characterize transferrin receptors further, both on intact membranes and after solubilization. Intact, isolated membrane fragments were examined for transferrin binding, both qualitatively by immunofluorescence and quantitatively by radiobinding. The amounts of ligand bound varied inversely with the quantities of residual maternal transferrin remaining at the time of testing. Scatchard plots revealed that the calculated affinity (K alpha) and the number of receptors increased substantially when transferrin was removed by initial washing with chaotropic agents. After dissociation from the membrane by detergents, occupied receptors largely retained bound transferrin, and transferrin binding by unoccupied receptors was also preserved. The stability of such ligand:receptor complexes was considerably enhanced at pH 5.0, and was apparently unaffected by prior treatment with chaotropic agents. Specific immunoprecipitation of solubilized radioiodinated membrane with rabbit antiserum to human transferrin, followed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate under reducing conditions, indicated a relative molecular mass for the unoccupied receptor of 90,000. These results confirm the existence of high-affinity receptors for transferrin on the trophoblast, and also delineate certain potential pitfalls in studies of their interactions with ligand.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"49-59"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17368418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Macromolecule transfer in the human trophoblast: transcobalamin II-vitamin B12 uptake.","authors":"W W Ng,&nbsp;R G Catus,&nbsp;R K Miller","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The accumulation of the large and hydrophilic IgG, TC II-B12 and B12 molecules is demonstrated for the first time in a human placental system which has metabolic and physiological functions. A trypsin-sensitive component is present in the human term placental uptake of TC II-B12, for which a placental membrane receptor has been previously identified; this component is absent for the accumulation of free B12, which has no known receptor. Analyses of the cytosol and incubation media indicate degradation, binding and release of TC II-B12 and B12 as TC II-B12, free B12 and TC I-like complexes. It is suggested that the human placental tissue slice be used for studies involving the binding, uptake and processing of macromolecules as exemplified by TC II-B12.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"145-59"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of trophoblast from normal and pre-eclamptic pregnancies cultured for prolonged periods.","authors":"S Aladjem,&nbsp;J Lueck","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Trophoblastic cells from normal and pre-eclamptic pregnancies have been cultured for prolonged periods of time in vitro. The growth characteristics, morphology and hormone production in vitro were similar in both. These results suggest that given a comparable environment in vitro, trophoblast from both normal and pre-eclamptic pregnancies does not behave differently. It is suggested, therefore, that the changes classically described in placentae from pre-eclamptic pregnancies are probably secondary to maternal disease rather than a reflection of an altered trophoblast.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"175-82"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HL-A antigen frequency distribution in patients with gestational choriocarcinoma and their husbands.","authors":"R S Berkowitz,&nbsp;J Hornig-Rohan,&nbsp;S Martin-Alosco,&nbsp;S Klein,&nbsp;D P Goldstein,&nbsp;R C Bast,&nbsp;W C DeWolf","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>HL-A (A,B,C, and DR) antigen frequency distribution was determined in 29 patients with choriocarcinoma and in their husbands, as well as in a matched control population of 21 healthy couples. All 29 patients had achieved complete sustained remission with chemotherapy. The HL-A antigen frequency distribution was normal in the choriocarcinoma patients and in their husbands and there was no abnormal HL-A antigen sharing between patients and their husbands. This study does not exclude the possibility that the pathogenesis of resistant choriocarcinoma may be dependent upon tumour-host histocompatibility.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"263-7"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Glutathione-mediated detoxification mechanisms of human placenta.","authors":"Y C Awasthi,&nbsp;D D Dao","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Glutathione peroxidase and GSH S-transferases play significant physiological roles in the detoxification mechanisms. The present study indicates that only selenium-dependent GSH-peroxidase I is present in human placenta. GSH-peroxidase II (non-selenium GSH-peroxidase) is totally absent from this tissue. The placental GSH-peroxidase has a relative molecular mass of 85 000 and is a tetramer of equal-size subunits. It is cyanide sensitive and its properties are similar to those of human erythrocyte GSH-peroxidase. In contrast to human liver, which has seven GSH S-transferases, the placenta has only one species of GSH S-transferase. This enzyme (pI 4.5, relative molecular mass 45 000, subunit size 22 500) has a different amino acid composition from that of liver and erythrocyte GSH S-transferases. From immunological studies, the placental GSH S-transferase appears also to have a genetic origin distinct from that of liver, erythrocyte and kidney GSH S-transferases. The placental GSH S-transferase does not express GSH-peroxidase activity. The overall substrate specificities of placental GSH S-transferase are also narrow, compared with liver enzymes. The present study indicates that, although these two GSH-linked detoxification mechanisms are operative in placenta, they appear to be less efficient than the similar mechanisms operating in liver.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"289-301"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plutonium movements across the haemochorial placenta of the guinea pig.","authors":"B J Kelman,&nbsp;M R Sikov","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In order to measure transplacental movements of plutonium without the complications of fetal accumulation, the fetal circulation of the guinea pig placenta (at 59 to 61 days of gestation) was perfused in situ. Dams were administered trace quantities of tritiated water (to indicate changes in maternal blood flow to the placenta) and 30 mu Ci/kg (i.e., approximately 500 micrograms/kg) of citrated 239Pu by intravenous injection. Plutonium-239 doses were large, approaching the LD50/30 (20 to 80 mu Ci/kg) for other species. Perfusion pressure, maternal cardiac rate, electrocardiogram, blood pressure, and respiratory rate were monitored continuously during each perfusion. Our measurements show that the clearance of plutonium from mother to fetus is small--2.5 +/- 0.5 microliter/min--an amount that is less than 20 per cent of the clearance of inorganic mercury. The indirect measurements of maternal blood flow to the placenta indicate that placental blood flow is greatly diminished in dams dosed with plutonium, which may partially account for the low clearance of plutonium.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"319-26"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18013884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Placental immunopathology in gestational diabetes.","authors":"G M Galbraith,&nbsp;R M Galbraith,&nbsp;E P Paulsen","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Gestational diabetes and insulin-dependent diabetes are characterized by distinct pathophysiological mechanisms. However, their presence in pregnancy poses similar risks to the fetus. It is possible that factors common to both diseases are responsible for the increased morbidity and mortality in offspring of such pregnancies. Recent studies of placentae from insulin-dependent diabetics revealed evidence of immunopathological change which may support the possible role of immunological factors in the complications of diabetic pregnancy. In the present study, we have similarly examined placentae derived from 30 pregnancies complicated by gestational diabetes and from 10 normal pregnancies. The most striking differences detected by immunofluorescence were increased amounts of clotting factors related to areas of fibrinoid necrosis, and large quantities of complement components C4 and C3 in the intervillous spaces and trophoblast basement membrane respectively. These results are similar to those found in placentae from insulin-dependent diabetics, suggesting that glucose intolerance in pregnancy, even of minor degree, is frequently associated with immunopathological processes that are reflected in the placenta.</p>","PeriodicalId":79246,"journal":{"name":"Placenta. Supplement","volume":"3 ","pages":"183-91"},"PeriodicalIF":0.0,"publicationDate":"1981-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"17817612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}