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Results for “PLACENTAL EXTRACTS”

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At least 595 records · Page 33Linked to original sources
PubMed1990

Studies on the ability of 65-kDa and 92-kDa tumor cell gelatinases to degrade type IV collagen.

Two major gelatinolytic metalloproteinases (gelatinases) of 65 kDa and 92 kDa were purified from a tumor cell line. Analysis of collagen degradation showed that native full-length Engelbreth-Holm-Swarm (EHS) type IV collagen was not cleaved by the purified gelatinases under conditions where native pepsin-extracted human placental type IV and V collagen and heat-denatured collagens were markedly degraded. However, EHS type IV collagen degradation was noted at 37 degrees C, i.e., under conditions that would favor denaturation of the collagen molecule in solution. The pattern of degradation of human placental type IV and V collagen appeared similar for both gelatinases. Zymogram analysis of gelatinase activity in the absence of sodium dodecyl sulfate (SDS) (to eliminate possible SDS-mediated denaturation of type IV collagen) confirmed the inability of 65 and 92-kDa gelatinases to degrade native full-length EHS type IV collagen. Under the same conditions and in SDS-polyacrylamide gel electrophoresis zymograms the gelatinases degraded pepsin-predigested EHS type IV collagen and pepsin-extracted human placental type IV collagen. These data suggest that the 65- and 92-kDa tumor cell gelatinases are not true type IV collagenases. Their ability to degrade pepsin-solubilized, or denatured, type IV collagen suggests a specificity for telopeptide precleaved or conformationally altered forms of this molecule.

Blotting, Northern↗
PubMed1992

Heparin neutralization by an extract of the human placenta: measurements and the concept of placental barrier to heparin.

A soluble extract from human placenta was found to neutralize heparin in a factor Xa-dependent heparin assay system. In comparison with serum the antiheparin activity of placenta tissue is 10 times higher (extract from 1 g of placenta neutralizes 8.94 +/- 3.31 IU of heparin; 1 ml of serum approximately 1 IU). The substance neutralizing heparin has not been identified, but it has been found that it is nondialyzable, is not adsorbed on heparin-Sepharose, and does not act progressively. It was suggested that the substance(s) responsible for the antiheparin effect in vitro might contribute to the failure of heparin to penetrate the placenta in vivo (placental barrier to heparin).

Chromatography, Affinity↗
PubMed1996

cis-acting elements and trans-acting proteins in the transcription of chorionic gonadotropin/luteinizing hormone receptor gene in human choriocarcinoma cells and placenta.

We investigated the cis-acting elements and trans-acting proteins responsible for a higher basal rate of transcription of hCG/LH receptor gene in human choriocarcinoma JEG-3 cells compared with normal term pregnancy placenta. Sequential deletion of the 5'-flanking region of the gene revealed that there are three negative control regions (NCRs) designated NCR1 (-1457 to -1373 bp), NCR2 (-1051 to -835 bp), and NCR3 (-480 to -184 bp), and a promoter (-184 to -1 bp). NCR3 was more inhibitory than the other two; nearly 60-70% of the inhibitory activity resides in a sequence between -480 to -276 bp, and the rest resides in the sequence between -276 to -184 bp. Gel mobility shift assays showed that the nuclear extracts from JEG-3 cells contained proteins that form three complexes with NCR1, two with NCR2, and six with NCR3. Many of the proteins that form the complexes in NCR3 are shared with the other two NCRs. Most of the proteins that form these complexes are less abundant in nuclear extracts from JEG-3 cells than in those from placenta. The JEG-3 cell nuclear extracts also contained proteins that form three complexes with the proximal promoter of the hCG/LH receptor gene. These proteins were identified as Ap2, Ap2-like I, and Sp1 from the competition studies with synthetic excess unlabeled Ap2, Sp1, and CTF/NF1 consensus oligodeoxynucleotides and/or supershift in gel mobility assays with anti-Ap2 antibody. Although the JEG-3 cell nuclear extracts contained abundant Ap2-like protein I and low levels of Ap2 and Sp1 proteins, the placental nuclear extracts contained low levels of Ap2-like protein I and very low to nondetectable levels of Ap2 and Sp1 proteins. Deoxyribonuclease I footprinting revealed that the nuclear extracts from JEG-3 cells and placent protected the -116 to -93 bp and -65 to -45 bp regions in the proximal promoter of the hCG/LH receptor gene that contain Sp1 and Ap2 binding sites, respectively. However, the nuclear extracts from placenta only partially protected these regions, which is consistent with lower levels of proteins that bind to the proximal promoter of the gene. In summary, we conclude that the presence of low levels of proteins that bind to the NCRs and the high levels of proteins, especially Ap2-like I, that bind to the proximal promoter can potentially explain higher transcription of the hCG/LH receptor gene in JEG-3 cells compared with that in normal term pregnancy human placenta.

Adaptor Protein Complex 2↗
PubMed2000

Placental alkaline phosphatase of high molecular weight in plasma of pregnant women in the last trimester of gestation.

Human blood plasma contains alkaline phosphatase (EC 3.1.3.1) isoenzymes from bone, liver and intestine. Blood of pregnant women in the third trimester of gestation also contains an isoenzyme of alkaline phosphatase from placenta, placental-AP (PLAP). Serum from pregnant women in the last trimester of gestation shows activity of soluble placental alkaline phosphatase (sol-PLAP). It is also known that a membrane bound high molecular weight placental-AP (high Mr-PLAP) is present in butanol extracts from placental tissue. Nevertheless, up to now, high Mr-PLAP has not been founded in human plasma. A method developed in this laboratory allows detection of membrane-bound alkaline phosphatase in pellet of plasma centrifuged at 100,000x g. By applying this method we have detected high molecular weight placental alkaline phosphatase in plasma of healthy pregnant women in the third trimester of pregnancy.

Alkaline Phosphatase↗
PubMed1989

Synergistic activity for high-proliferative-potential colony-forming cell (HPP-CFC) development, stable to trypsin digestion, present in pregnant mouse uterus and placenta extract.

In this paper we describe a crude pregnant mouse uterus and embryo extract (PMUE) prepared from CFW/ep mice which was able to stimulate the proliferation of high-proliferative-potential colony-forming cells (HPP-CFC) of bone marrow of normal mice, in vitro, in semisolid agar culture system. The development of that primitive murine progenitor cells requires the presence of a macrophage-stimulating factor (CSF-1) plus a synergistic factor (SF). The biological activity of both factors was present in our extracts. The higher SF activity was found in uterine plus placental tissues extracts. The SF was precipitated over 45 per cent ammonium sulfate saturation, and behaved as a nondialyzable substance, remained unaffected by trypsin digestion, and was heat-stable (70 degrees C for 15 min).

Animals↗
PubMed1977

A human albumin of placental origin (albumin Rhodia) tested for tolerance.

Fifty infusions, each containing 125 ml 20% human albumin extracted from placental tissue, were tested in clinical practice. No effects such as changes in the patient's BP, pulse rate and rectal temperature were noted during the observation period, and no side-effects such as pain, dyspnoea, nasal symptoms, exanthema or thrombophlebitis, nor any other symptoms to suggest that the solution was not well tolerated.

Adult↗
PubMed1989

Purification and characterization of the adenosine A2-like binding site from human placental membrane.

We have purified and characterized the adenosine A2-like binding site from human placental membranes. 5'-N-Ethylcarboxamido[2,8-3H]adenosine ([3H]NECA) binds to this site, with a Kd of 240 nM and a Bmax of 13.0 pmol/mg in human placental membranes. The adenosine A2-like binding site was purified after extraction from placental membranes with 0.1% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid. The purification included ammonium sulfate precipitation and concanavalin A, DEAE-Sephadex, and Sepharose 6B gel filtration chromatographies. The protein was purified 127-fold to homogeneity, with a final specific activity of 1.5-1.9 nmol/mg of protein and a 5.5-8.1% yield of binding activity from the membranes. The purified protein had similar binding properties and an identical potency order for displacement of [3H] NECA by adenosine analogs as the initial membranes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified protein revealed a single band at 98 kDa which coeluted with [3H]NECA binding activity during Sepharose 6B gel filtration chromatography. In 0.1% Triton X-100, the binding complex has a Stokes radius of 70 A, a sedimentation coefficient of 6.9 S, and a partial specific volume of 0.698 ml/g. The detergent-protein complex has a calculated molecular mass of 230 kDa. The estimated frictional ratio is 1.5. The native binding complex appears to consist of a dimer of identical subunits. The function of this ubiquitous protein remains unclear.

Cell Membrane↗
PubMed1990

The effect of human placental protein 14 (PP14) on the production of interleukin-1 from mitogenically stimulated mononuclear cell cultures.

Crude human decidual tissue extracts containing placental protein 14 (PP14) were shown to inhibit the production of interleukin-1 beta (IL-1) from mitogenically stimulated mononuclear cell cultures. The inhibition was dose-dependent over the range of PP14 concentrations investigated (0-8.0 mg/l) and was effective on both phytohaemagglutinin-(PHA) and lipopolysaccharide- (LPS)-induced IL-1 secretion. Using these culture systems, a PP14 concentration of 1.0 mg/l induced a 34% suppression of IL-1 secretion following LPS stimulation and 22% following PHA stimulation. For PHA stimulation the suppression of IL-1 secretion was effective throughout the culture period investigated (0-89 hr). Individual crude decidual extracts inhibited the incorporation of [3H]thymidine into PHA-stimulated lymphocytes, such inhibition being partially reversed by the addition of exogenous recombinant IL-1 to the cultures. These results suggest that the previously reported immunosuppressive activity of PP14 may be mediated by the suppression of IL-1 secretion.

Cells, Cultured↗
PubMedDate not supplied

A trophoblast specific antigen, recognized by monoclonal antibody MA21, locates a unique trophoblast cell population in the murine placenta.

Monoclonal antibody MA21 recognized a 44kDa plasma membrane protein on F9 teratocarcinoma cells, trophectoderm of mouse peri-implantation-stage blastocyst and ectoplacental cone cells of 5 day postcoitum implanted blastocyst (Vernon, Linnemeyer and Hamilton, 1989). We show here that this antigen is expressed by trophoblast cells of the maturing placenta. Immunohistochemical assays of early and mature placental tissue sections, indirect immunofluorescence labelling of placental cultures and blastocyst outgrowths in vitro, and immunoprecipitation of 35S-labelled NP-40 extracts of placental cultures indicate the presence of a plasma membrane-associated antigen with the same characteristics as MA21 antigen of peri-implantation embryos and F9 teratocarcinoma cells. In sections of placentae, antigen-positive cells are always situated in a thin layer between trophoblastic giant cells and maternal tissue. In cultures of postimplantation stage embryos, attached trophoblast cells express MA21 antigen initially, but following transformation to the giant cell state, antigen is no longer expressed. These results indicate the presence of a plasma membrane protein antigen associated with a distinct population of cells believed to be trophoblast. We believe that these cells are the foremost trophoblast cells opposing maternal decidua and that they may give rise to secondary trophoblastic giant cells.

Animals↗