Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of glucocorticoids on hormone secretion by human placenta in organ culture were studied. The addition of cortisol resulted in a fourfold increase in human chorionic gonadotropin (hCG) secretion over that in untreated cultures after 144 hours' incubation (P less than 0.05), and a twofold increase in hCG was observed in the presence of cortisone (P less than 0.01). Dexamethasone stimulated hCG secretion in a dose-response manner (r = 0.9542; P less than 0.01). Progesterone, which suppresses hCG under these conditions, decreased the cortisol-enhanced secretion of hCG (r = -0.9794; P less than 0.01). No change in the secretion of human chorionic somatomammotropin was observed, but glucocorticoids increased heat-stable alkaline phosphatase activity (P less than 0.001). The physiologic significance of glucocorticoid effects on placental hormone synthesis is discussed.
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PMID:Stimulation of human chorionic gonadotropin secretion by glucocorticoids. 706 25

The expression of the placental isoenzyme of alkaline phosphatase and the alpha subunit of chorionic gonadotropin was examined in a series of cloned lines of Chang liver cells. both placental gene products show large quantitative variation in the amounts made (over 30-fold) among the various clones. This variation occurs independently for both proteins. These results suggest that these placental-specific genes are discordantly regulated. Because karyologic analysis of several clones shows significant variation in the chromosome content, we cannot determine whether such expression results from true independent mechanisms controlling expression or from variation in gene dosage.
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PMID:Independent expression of alpha-HCG and placental alkaline phosphatase in clonal human cell lines. 727 3

Embryonic stem cells have the ability to remain undifferentiated and proliferate indefinitely in vitro while maintaining the potential to differentiate into derivatives of all three embryonic germ layers. Here we report the derivation of a cloned cell line (R278.5) from a rhesus monkey blastocyst that remains undifferentiated in continuous passage for > 1 year, maintains a normal XY karyotype, and expresses the cell surface markers (alkaline phosphatase, stage-specific embryonic antigen 3, stage-specific embryonic antigen 4, TRA-1-60, and TRA-1-81) that are characteristic of human embryonal carcinoma cells. R278.5 cells remain undifferentiated when grown on mouse embryonic fibroblast feeder layers but differentiate or die in the absence of fibroblasts, despite the presence of recombinant human leukemia inhibitory factor. R278.5 cells allowed to differentiate in vitro secrete bioactive chorionic gonadotropin into the medium, express chorionic gonadotropin alpha- and beta-subunit mRNAs, and express alpha-fetoprotein mRNA, indicating trophoblast and endoderm differentiation. When injected into severe combined immunodeficient mice, R278.5 cells consistently differentiate into derivatives of all three embryonic germ layers. These results define R278.5 cells as an embryonic stem cell line, to our knowledge, the first to be derived from any primate species.
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PMID:Isolation of a primate embryonic stem cell line. 754 5

The chemiluminescent reaction of lucigenin with various reducing sugars and reducing compounds has been studied. It was found that dihydroxyacetone gave the most intense chemiluminescence (CL). We have developed highly sensitive chemiluminescent methods for alkaline phosphatase (ALP) based on the production of dihydroxyacetone using NADP+ or glycerol-3-phosphate as substrate. The detection limits for ALP using each substrate were 1.25 x 10(-19) mol/assay and 2.5 x 10(-19) mol/assay, and the coefficient of variation (n = 7) was 2.8% and 3.7%, respectively. We have also applied the method using NADP+ as substrate in enzyme immunoassays (EIA) for cholecystokinin (CCK) and human chorionic gonadotropin (hCG). CCK-8 (octapeptide sulphated form of a carboxy terminal fragment of CCK) concentrations released from alimentary canal of rat were assayed using the chemiluminescent EIA (CLEIA) and a fluorimetric EIA (ALP label). The correlation between CCK-8 values obtained by these methods was y = 1.04x + 18.21, r = 0.946, n = 28. hCG values in serum and in urine were measured. The correlation between hCG values in serum samples obtained using the CLEIA and a time-resolved fluoroimmunoassay (TR-FIA), and in urine samples obtained using the CLEIA and the fluorimetric EIA using ALP were satisfactory. The correlations were y = 1.00x - 0.04, r = 0.997 (n = 51) and y = 1.00x - 0.03, r = 0.999 (n = 10), respectively.
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PMID:A new highly sensitive chemiluminescent assay of alkaline phosphatase using lucigenin and its application to enzyme immunoassay. 776 11

An immunohistochemical study of 15 ovarian formalin-fixed, paraffin-embedded dysgerminomas showed positive staining of tumor cells for vimentin in all cases. Ten dysgerminomas stained for cytokeratin 18. Desmin positivity of single tumor cells was detected in four dysgerminomas. Glial fibrillary acidic protein was present in two tumors. Prominent human beta chorionic gonadotropin staining was seen in one tumor. S-100 protein was found in two and carcinoembryonic antigen in one of the dysgerminomas. Placental alkaline phosphatase was present in 12 of the 15 tumors studied. The heterogeneity of the cytoskeletal profile and of other markers showed some similarities to our previously published results on testicular seminomas. Thus, in contrast to previous concepts, dysgerminoma, as is the case with its testicular counterpart the seminoma, appears to be capable of further differentiation, albeit at a primitive level. Our observations also may help to elucidate the relationship between dysgerminoma and other nondysgerminomatous ovarian germ cell tumors, and may be of help in the differential diagnosis with poorly differentiated carcinoma, ovarian lymphoma, or other germ cell tumors.
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PMID:Differentiation potential of ovarian dysgerminoma: an immunohistochemical study of 15 cases. 782 17

A novel separation-free sandwich-type enzyme immunoassay for proteins is performed by designing an electrochemical detection system that enables preferential measurement of surface-bound enzyme-labeled antibody relative to the excess enzyme-labeled reagent in the bulk sample solution. In this initial model system, the assay is carried out using gold-coated microporous nylon membranes (pore size 0.2 micron) which are mounted between two chambers of a diffusion cell. The membrane serves as both a solid phase for the sandwich assay and the working electrode in the three-electrode amperometric detection system. The capture monoclonal antibody is immobilized covalently on the gold side of the membrane via a self-assembled monolayer of thioctic acid. In the separation-free sandwich assay, both model analyte protein (human chorionic gonadotropin; hCG) and alkaline phosphatase labeled anti-hCG (ALP-Ab) are incubated simultaneously with the immobilized capture anti-hCG antibody. Surface-bound ALP-Ab is spatially resolved from the excess conjugate in the bulk sample solution by introducing the enzyme substrate (4-aminophenyl phosphate) through the back side of the porous membrane. The substrate diffuses rapidly through the porous membrane where it first encounters bound ALP-Ab at the gold surface. The enzymatically generated product, aminophenol, is detected immediately by oxidation at the gold electrode (at +0.19 V vs Ag/AgCl), and the magnitude of current is directly proportional to the concentration of hCG in the sample. The response time after substrate addition is less than 1 min, although maximum response toward the analyte protein requires a sample/conjugate preincubation time of 30 min with the porous electrode.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Separation-free sandwich enzyme immunoassays using microporous gold electrodes and self-assembled monolayer/immobilized capture antibodies. 801 31

Four examples of spermatocytic seminoma with a predominant anaplastic component occurred in men 33 to 43 years of age, without histories of cyptorchidism. The seminomas presented with painless testicular masses recognized 3 to 18 months before orchiectomy. Preoperative serum measurements of human chorionic gonadotropin and alpha-fetoprotein were negative. All tumors contained areas (10% to 30% of the tumor) in which the three cell types characteristic of conventional spermatocytic seminoma could be identified under light microscopy. The predominant anaplastic component also contained the three cell types, but the nuclei had prominent nucleoli with granular and filamentous chromatin. In addition, sheets of cells with vesicular nuclei and prominent nucleoli superficially resembling embryonal carcinoma were found. There were numerous large mononuclear and multinucleated giant cells with bizarre nuclei and prominent nucleoli, but no sarcomatous elements. Many normal and abnormal mitotic figures were present. Tunical and vascular invasion and extensive necrosis were constant features. Immunohistochemistry documented p53 protein overexpression in two tumors, but neoplastic cells were negative with immunostains for placenta-like alkaline phosphatase, leukocyte common antigen, neuron-specific enolase, alpha-fetoprotein, human chorionic gonadotropin, vimentin, and cytokeratins. Ultrastructural examination of the anaplastic component showed large rope-like nucleoli, but the cytoplasmic features were similar to those of conventional spermatocytic seminoma. Despite the presence of a major anaplastic component, no patient has developed metastasis. Larger series and longer follow-up are needed to understand the natural history of these neoplasms.
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PMID:Anaplastic variant of spermatocytic seminoma. 869 7

Cell differentiation is supported much better by gels of extracellular matrix than by the same matrix provided as a rigid substrate. Many cell types including normal and malignant trophoblast cells, however, form multicellular multilayered aggregates on matrix gels with increased cell-to-cell contacts as compared to regular monolayers on rigid matrix substrates. In such cultures, it remained open, so far, whether stimulated expression of differentiation markers is caused by enhanced cell-to-cell communication or is displayed only by cells in direct contact to the gel. Therefore, choriocarcinoma cells (BeWo) were grown as aggregates: (a) on gels of the basement membrane-like Matrigel, (b) on plastic coated with poly-HEMA, or (c) as aggregates (spheroids) in suspension culture. Production of the differentiation marker chorionic gonadotropin was stimulated significantly in aggregates attached to gels of Matrigel or to the poly-HEMA substrate but not in suspended spheroids. With respect to cell-cell communications, however, expression of E-cadherin mRNA was not altered in any type of aggregates, as compared to control cultures on plastic. The expression of connexin43 mRNA (not of connexin26) was increased only in suspended spheroids, while microinjection of the fluorescent dye Lucifer Yellow suggested that cell communication via gap junctions was absent from cells grown as monolayers and was not induced in any type of aggregate. When cells were grown on gels of Matrigel, the relevance of direct cellular contact to the substrate for differentiation was analyzed by immunohistochemistry. Trophoblastic differentiation markers (chorionic gonadotropin, placental lactogen, placenta-type alkaline phosphatase, and pregnancy-specific glycoprotein beta 1) as well as the proliferation marker Ki-67 were not preferentially expressed in cells that were in contact with the gel. Similar random distributions of all these markers were also observed in spheroids cultured in suspension. The distributions of several matrix molecules and of different integrins were comparable between aggregates on matrix gels and those in suspension culture. According to these data, cell-cell communication appears to play a subordinate role for cytodifferentiation in cell aggregates on matrix gels, so that substrate anchorage and physical properties of the substrate may be the decisive factors. Interestingly, however, direct contact to the substrate does not seem to be essential for the stimulation of differentiation in cells on matrix gels. The results are discussed in the context of the "tensegrity"-model for cell-matrix interactions in which proper mechanical properties of the substrate are important for the regulation of cell differentiation by allowing a balanced integrity of external and cell-internal tensile forces.
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PMID:The role of matrix contact and of cell-cell interactions in choriocarcinoma cell differentiation. 882 26

Structures of N-linked sugar chains are species and tissue specific and change in the course of tumorigenesis. Sialyl linkages of human placental glycoproteins are exclusively Neu5Ac alpha2-->3Gal, whereas Fuc alpha1-->2Gal and Neu5Ac alpha2-->6Gal residues are expressed in human chorionic gonadotropin and alkaline phosphatase, which are produced in human choriocarcinoma JEG-3 and BeWo cells. In the present study, to elucidate the enzymological and molecular biological basis of the structural changes that occur in the course of tumorigenesis, alpha1-->2 fucosyltransferase, alpha2-->3 and alpha2-->6 sialyltransferase activities, and the expression levels of the corresponding mRNAs were measured. The alpha2-->3 sialyltransferase activity did not change as a result of tumorigenesis; however, the alpha2-->6 siayltransferase activity and alpha1-->2 fucosyltransferase activity in JEG-3 and BeWo cells increased to levels several times higher than those in placenta Competitive PCR analysis showed that the expression levels of mRNA encoding alpha1-->2 fucosyltransferase and mRNA encoding alpha2-->6 sialyltransferase increased significantly as a result of tumorigenesis, indicating that such structural changes are regulated at the level of transcription of these glycosyltransferase genes.
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PMID:Elevation of alpha2-->6 sialyltransferase and alpha1-->2 fucosyltransferase activities in human choriocarcinoma. 976 57

Embryonic alkaline phosphatase (EAP) is expressed during the preimplantation period of mouse development; however, its function is unknown. To determine whether the absence of an EAP gene affects development of preimplantation embryos, we studied mice homozygous for the disrupted EAP gene (EAP.ko mice). Time to reach morphologically definedpreimplantation stages, preimplantation loss, cell count, gestation length, and litter size were monitored, and it was found that EAP.ko embryos have slower development and higher rates of degeneration during in vitro preimplantation development. In vivo, EAP.ko mice had a longergestation, smaller litter size, and fewer cells at 93 hr after human chorionic gonadotropin injection. Furthermore, there was no compensation for the absence of EAP gene in EAP.ko embryos by other isozymes of alkaline phosphatase. We conclude that the presence of an active EAP gene is beneficial for preimplantation development of the mouse embryo, and its absence leads to fewer blastocysts in vitro, delayed parturition, and reduced litter size in vivo.
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PMID:Effects of disruption of the embryonic alkaline phosphatase gene on preimplantation development of the mouse. 1076 88


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