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PubMed1975

Glycosidases in Cell Wall-degrading Extracts of Ripening Tomato Fruits.

Enzyme preparations were obtained from cell wall debris of tomato (Lycopersicon esculentum L. cv. Tropic) fruits at various stages of ripeness and were assayed for glycosidase and polysaccharidase activities. In addition to polygalacturonase (mol wt 40,000), ripening fruits contain beta-galactosidase (mol wt 63,000) and beta-1, 3-glucanase (mol wt 12,000). The beta-glycosidases, unlike polygalacturonase, are active in extracts of green fruits. Placental tissue shows very low polygalacturonase but increasing beta-galactosidase and beta-1, 3-glucanase activities as ripening proceeds. A large change in the susceptibility of the walls to hydrolase action occurs before the stage in which the greatest polygalacturonase activity occurs. The possibility that the beta-glycosidases contribute to the wall modifications that lead to fruit softening is discussed.

Journal Article↗

PubMed1984

Inhibition of estrogen synthetase (aromatase) by 4-cyclohexylaniline.

4- Cyclohexylaniline , a structurally simple analog of the drug aminoglutethimide [d,l-3-(4-aminophenyl)3-ethyl-2, 6- piperidinedione ], was found to be an effective inhibitor of the aromatization of testosterone and androstenedione. With human placental microsomes, 4- cyclohexylaniline was a more potent aromatase inhibitor than d-aminoglutethimide. For androstenedione and testosterone aromatization, competitive inhibition by 4- cyclohexylaniline was observed; a Ki value of 0.14 microM was found with both substrates. A Ki value for d-aminoglutethimide inhibition of androstenedione aromatization of 0.3 microM was obtained. Kinetic analysis of the simultaneous inhibition by 4- cyclohexylaniline and d-aminoglutethimide suggests that both compounds bind to the same site on the enzyme. 4- Cyclohexylaniline and d-aminoglutethimide were also tested for inhibition of androstenedione aromatization in human and rat ovarian microsomes. With the human aromatase, both inhibitors exhibited approximately the same effectiveness; with rat aromatase, however, d-aminoglutethimide was more potent. 4- Cyclohexylaniline and d-aminoglutethimide were also assayed for their inhibition of cytochrome P-450-catalyzed cholesterol side-chain cleavage. When the enzyme from human placenta was used, 4- cyclohexylaniline was 24-fold less effective than d-aminoglutethimide, and when the purified bovine adrenal enzyme was used, it was 16-fold less effective. Thus, 4- cyclohexylaniline exhibits inhibitory specificity toward aromatase. Difference spectral measurements using crude placental microsomes and cholate extracts of these microsomes show that binding of 4- cyclohexylaniline produces a type II spectral change; this is indicative of coordination of the arylamine to the heme-iron of the aromatase cytochrome P-450. Consistent with this spectral finding was the fact that blockade of the amino group of both 4- cyclohexylaniline and d-aminoglutethimide by acetylation resulted in essentially complete loss of inhibitory activity toward aromatase. These findings establish that the arylamine moieties of both 4- cyclohexylaniline and d-aminoglutethimide are essential for their inhibitory actions. The potent aromatase inhibition by 4- cyclohexylaniline indicates that neither the complex glutarimide ring nor the chiral 3-ethyl substituent of d-aminoglutethimide is required for high affinity binding of this class of inhibitor to aromatase P-450.

Aminoglutethimide↗

PubMed2006

[Study of the proteins associated with Sa antigen].

OBJECTIVE: To study the proteins associated with Sa antigen, a target of the anti-Sa antibodies specific for rheumatoid arthritis, and to elucidate the nature of these proteins. METHODS: Sa antigen was extracted from fresh human placental tissue by anion exchange chromatography and subjected to SDS-PAGE electrophoresis. Serum samples were collected from 155 patients with connective tissue diseases, including rheumatoid arthritis (71 cases), ankylosing spondylitis (11 cases), psoriatic arthritis (7 cases), reactive arthritis (7 cases), juvenile idiopathic arthritis (4 cases), osteoarthritis (5 cases), polymyalgia rheumatica (6 cases), gout (6 cases), systemic lupus erythematous (7 cases), Sjogren's syndrome (10 cases), adult onset Still's disease (3 cases) and Sa antibodies were detected by immunoblotting. The gel bands corresponding to the stained bands were excised, trypsin-digested in gel, and analyzed by LC-ESI-MS/MS. Once identified, the protein was recombinate and expressed in Escherichia coli, and the antibodies were detected by immunoblotting. Then the protein was citrullinated to detect the antibodies again. RESULTS: Immunoblotting showed anti-Sa antibodies, band (s) with apparent molecular weight of 50 000 (and) 55 000, in 34 of the 71 patients of rheumatoid arthritis and 4 of the 84 patients of other rheumatic diseases, with a sensitivity rate of 47.9% and a specificity rate of 95.2%. The target protein was identified as vimentin. The positive rate of anti-vimentin antibody was statistically different between the RA patients and the patients with other rheumatic diseases (P = 0.005), with a sensitivity rate of 36.6% and a specificity rate of 83.3%, respectively. But there was no obvious correlation between anti-vimentin antibody and anti-Sa antibodies (Kappa = 0.316). The positive rate of anti-citrullinated vimentin antibody was significantly higher in the RA patients than in the patients with other rheumatic diseases (P < 0.01), with a sensitivity rate of 49.3%. There was a high correlation between anti-citrullinated vimentin antibody and anti-Sa antibodies (Kappa = 0.746), albeit a low specificity rate (86.9%). CONCLUSION: Citrullinated vimentin is closely correlated with Sa antigen.

Antibody Specificity↗

PubMed1995

Potent activation of nitric oxide synthase by garlic: a basis for its therapeutic applications.

Garlic (Allium sativum L.) is thought to have a variety of therapeutic applications including inhibition of platelet aggregation. Many of the therapeutic actions of garlic parallel the physiological effects of nitric oxide and may be explained by its ability to increase nitric oxide synthase activity intracellularly. Our studies showed that both water and alcoholic extracts of garlic are very potent inhibitors of platelet aggregation induced by epinephrine and ADP. Similar dilutions of garlic extract also activated nitric oxide synthase activity in isolated platelets in vitro. The same extract was also very effective in activating nitric oxide synthase activity in placental villous tissue. The addition of garlic extracts increased nitric oxide synthase activity in a dose-dependent manner. Nitrite levels in the supernatants of incubated placental villous tissue were similarly increased. Activation of calcium-dependent nitric oxide synthase and the subsequent production of nitric oxide is probably the most novel mechanism yet claimed by which garlic can exert its therapeutic properties.

Adenosine Diphosphate↗

PubMed1979

The wheat germ cell-free system possesses processing activity for the precursor of human placental lactogen.

1. Total RNA was extracted from human term placenta and mRNA purified by chromatography on oligo(dT)-cellulose. The poly(A)-containing fraction stimulated amino acid incorporation 5- to 10-fold in the wheat germ cell-free system. Immunoprecipitation with an anti-lactogen serum indicated that 14-27% of the peptides synthesized in vitro contained antigenic determinants of this hormone. 2. Analysis of the [3H]leucine labelled product in the immunoprecipitate on sodium dodecyl sulfate-polyacrylamide gels revealed a complex mixture of polypeptides. Two heavily labelled bands (I and III) were seen corresponding in mobility with pre-lactogen (Mr = 25 000) and native lactogen (Mr = 22 200), each accounting for about 30% of the immunoprecipitable radioactivity. Two additional bands with an intermediate mobility were also observed. 3. Synthesis of the hormone was inhibited by 7-methylguanosine-5'-monophosphate suggesting the presence of a 7-methylguanosine 'cap' on the 5'-end of the mRNA for lactogen. 4. Peptide analysis of the cyanogen bromide cleavage products of band I, band III and authentic lactogen showed marked similarities in their primary structure. The precursor molecule, however, was lacking the N-terminal peptide present in authentic hormone indicating the presence of an extension of 25 amino acids at this side of the molecule. 5. The presence of one or several processing enzymes in the wheat germ cell-free system was indicated by the effect of Triton X-100. Low concentrations of this detergent (0.04%) while inhibiting the protein synthesizing activity for only 15%, completely abolished the precursor cleavage activity. Under these conditions only pre-lactogen was detected in the immunoprecipitate.

Female↗

PubMed1993

The primary structure of pancreatic polypeptide from a primitive insectivorous mammal, the European hedgehog (Erinaceous europaeus).

Pancreatic polypeptide (PP) has been isolated from extracts of the pancreas of the European hedgehog (Erinaceous europaeus) which is a representative of the order Insectivora, deemed to be the most primitive group of placental mammals. Pancreatic tissues were extracted in acidified ethanol and the peptide was purified chromatographically using a PP C-terminal hexapeptide amide specific radioimmunoassay to monitor purification. Two major PP-immunoreactive peptides were baseline-resolved following the final analytical reverse phase HPLC fractionation. Each was separately subjected to plasma desorption mass spectroscopy (PDMS) and gas-phase sequencing. The molecular masses of each peptide were similar: (I) 4237.6 +/- 4 Da and (II) 4238.2 +/- 4 Da. The full primary structures of each peptide were deduced and these were identical: VPLEPVYPGDNATPEQMAHYAAELRRYINMLTRPRY. The peptides were deemed to be amidated due to their full molar cross-reactivity with the amide-requiring PP antiserum employed in radioimmunoassay. The molecular mass (4233.8 Da) calculated from the sequence was in close agreement with PDMS estimates and the reason for the different retention times of each peptide is unknown at present. Hedgehog PP exhibits only 2 unique amino acid substitutions, at positions 1 (Val) and 19 (His), when compared with other mammalian analogues.

Amino Acid Sequence↗

PubMed1981

Enrichment of selected active human gene sequences in the placental deoxyribonucleic acid fraction associated with tightly bound nonhistone chromosomal proteins.

A DNA fraction which is highly enriched in active gene sequences and tightly associated with a subset of nonhistone chromosomal proteins has been isolated from human placenta. After extraction with 2 M NaCl, placental chromatin was separated into two distinct components by centrifugation. Of the total DNA, approximately 96% (DNA-S) is protein free, while the remaining 4% (DNA-P) is tightly complexed with nonhistone chromosomal proteins. Reassociation studies revealed that the DNA-P fraction was enriched 22-fold in actively transcribed human placental lactogen gene sequences, while the DNA-S fraction was correspondingly depleted 22-fold in these sequences. Approximately 45% of the sequences present in DNA-P (equivalent to 1.8% of the genome) were not present in the DNA-S fraction. Reassociation of nick-translated DNA-P to DNA from a partial digest of DNase I treated nuclei indicated that 27% of the DNA-P sequences were DNAase I sensitive, suggesting they may represent actively transcribed gene sequences. Analysis of the overall sequence organization of DNA-P showed that relative to unfractionated DNA and DNA-S, DNA-P was enriched in single-copy sequences, slightly enriched in the class of middle repetitive sequences from C0t 0.01 to 100 M.s, devoid of the more highly repetitive sequences (C0t less than or equal to 0.01). The distribution of total active placental genes between DNA-P and DNA-S was measured by hybridization with a complementary DNA probe transcribed from total polysomal poly(A+) messenger RNA. We found that 57% of this cDNA probe reassociated to DNA-P and 58% to DNA-S, while 95% reassociated to DNA-P mixed with DNA-S at the observed ratio of 4 to 96, suggesting that the DNA-P fraction contained a different population of active gene sequences than DNA-S. From these results we estimate that approximately 85% of the transcribed sequences appear to be distinctly distributed and equally proportioned between DNA-P and DNA-S, while approximately 15% of the transcribed sequences are common to both fractions. We suggest that the strong affinity of the tightly bound nonhistone chromosomal proteins for the DNA-P fraction indicates a likely role for these proteins in the regulation of gene expression.

Base Sequence↗

PubMedDate not supplied

Removal of heme from preparations of human chorionic somatomammotropin.

The operations involved in the extraction of chorionic somatomammotropin from human placentas cause hemolysis of blood which is present in placental tissue and contamination of crude extract with large amounts of hematic pigments. Most of the pigments are removed by the purification procedure. The portion of purified hCS with high heme content was subjected to treatments with acid acetone and neutral butanone on the basis of procedures generally used for the separation of heme and protein portions in hemoproteins. Both treatments resulted in the removal of heme from hCS; the treatment using butanone was more efficient than the one using acetone. After treatment with both organic solvents, the immunological activity measured with radial immunodiffusion was entirely retained while binding activity on rat ventral prostate particles was slightly decreased.

Acetone↗

PubMed1975

The distribution of placental lactogen in the human term placenta.

Serial frozen sections of human term placentae were examined by quantitative morphology and, after extraction, by a radioimmunoassay for human placental lactogen (HPL). The total quantity of HPL in the placenta was estimated as 720 mg. The amount of HPL was related to the amount of trophoblast in any area, but otherwise did not vary in different parts of the placenta. A semi-logarithmic relationship was observed between the amount of HPL and the percentage trophoblast in a section. It is suggested that the amount of HPL in a given area of the placenta is related to the blood-flow in that area.

Cell Count↗

PubMed1995

Hepatocyte growth factor promotes the growth of cytotrophoblasts by the paracrine mechanism.

Both placental and decidual tissues contained extractable HGF, the former HGF level (31.4 +/- 23.4 ng/mg total protein) being approximately 30 times the latter HGF level. When the localization of HGF protein and HGF mRNA in placental tissues was examined by immunohistological staining and in situ hybridization, HGF protein and HGF mRNA were detected in the mesenchymal cells of the placenta, but were absent in the cytotrophoblast and syncytiotrophoblast. Although c-met protein was expressed in the cytotrophoblast, this receptor was not detectable in the syncytiotrophoblast by immunohistochemical methods. c-met mRNA was detected in placental cell line (tPA30-1) and 4 choriocarcinoma cell lines (BeWo, Jar, Jeg-3, and NUC-1), but HGF mRNA was absent in these cells. When cytotrophoblast cells were cultured in a serum-free medium in the presence of HGF, their DNA synthesis was enhanced depending on the HGF concentration, although human placental lactogen secretion itself was not affected by HGF. These results demonstrated that HGF promotes the growth of the cytotrophoblast by the paracrine mechanism, although it does not serve as a placental differentiation factor.

Base Sequence↗

PubMed1990

Metabolism of cocaine by human placentas: implications for fetal exposure.

To assess placental metabolism of cocaine, placentas were obtained at the time of delivery and the microsomes were extracted by ultracentrifugation within 2 hours. Placental microsomes were cultured with cocaine at physiologic plasma concentrations similar to those of cocaine users (0.75 micrograms/ml). Two control groups were established. In the first group an anticholinesterase was added to the culture to suppress enzyme activity, and in the second cocaine was cultured alone without placental microsomes to obtain baseline spontaneous conversion of the drug. The results indicate that cocaine is biotransformed by the human placenta, presumably by cholinesterase activity. This suggests that the placenta may provide a moderate degree of protection from cocaine-induced morbidity, such as abruptio placentae and fetal growth retardation, by converting cocaine into less active metabolites. These results also have pharmacogenetic implications because cholinesterase activity varies among individuals. Hence placentas that cannot transform the drug may place the conceptus at greater risk of developmental abnormalities.

Biotransformation↗

PubMed1985

Isolation and characterization of four new placental tissue proteins (PP18, PP19, PP20, PP21).

Four new soluble placental tissue proteins (PP18, PP19, PP20, PP21) have been isolated to purity from saline extracts of human term placentas. Two of the new proteins appear to be partly associated with placental membranes; they also could be detected in placental protein fractions obtained by extracting the insoluble part of the placental tissue with solubilizing agents after the soluble material had been removed by washing with saline. The new placental proteins were characterized by their physical properties as well as by their carbohydrate and aminoacid compositions. Specific antisera to the new proteins were obtained by immunizing animals with the corresponding purified proteins. They were used to detect and quantitate the new proteins in extracts of placentas and other human tissues by immunochemical methods. From one human term placenta an average of 2 mg PP18, 90 mg PP19, 0.5 mg PP20, and around 7 mg PP21 could be extracted. None of these new proteins is specific to the placenta; they also were found to occur in extracts of certain other human tissues. The immunohistochemical localization of these proteins as well as measurement of their concentrations in body fluids by sensitive radioimmunoassays are presently under investigation.

Amino Acids↗

PubMed1990

Resorption of CBA/J x DBA/2 mouse conceptuses in CBA/J uteri correlates with failure of the feto-placental unit to suppress natural killer cell activity.

Lipid extraction was used to study the natural killer (NK) suppressive activity of individual feto-placental units. Normal pregnancies showed a lipophilic NK cell suppressive factor that was gestational day specific. Feto-placental units from CBA/J x DBA/2 pregnancies were deficient in the NK cell suppressive factor when compared to normal CBA/J x BALB/c pregnancies. The frequency of non-suppressive feto-placental units from CBA/J x DBA/2 pregnancies correlated with the frequency of feto-placental units infiltrated with NK cells and the frequency of spontaneous resorption. Our results implicate a deficiency of NK suppressive activity in the feto-placental unit as a contributing factor in spontaneous fetal resorption.

Animals↗

PubMedDate not supplied

Human placental norepinephrine transporter mRNA: expression and correlation with fetal condition at birth.

The purpose of this study was to determine the primary form of human placental norepinephrine transporter (hNET) mRNA expressed in the human placenta and to compare the level of expression in normal pregnancies and in pregnancies complicated by drug exposure or other forms of physiological derangement. We used the hNET cDNA to measure RNA extracted from placenta and examined placental RNA following complicated and uncomplicated pregnancies. To compare transporter expression and its relation to fetal condition at birth, umbilical arterial plasma catecholamine levels, umbilical arterial blood gases and placental transporter mRNA level were compared by linear regression analysis. Uncomplicated pregnancies had a higher level of placental norepinephrine transporter mRNA than complicated pregnancies. An inverse relationship between umbilical cord norepinephrine level and transporter expression was demonstrated. We conclude that placental transporter expression represents an important and newly described metabolic function of the placenta. Placental catecholamine clearance mediated via the placental NET may be important in the pathophysiology of disorders associated with placental dysfunction, impaired placental blood flow or intrauterine growth retardation. This may also explain the adverse effects of drugs, such as cocaine, which block catecholamine transport.

Apgar Score↗

PubMed1982

Lipoprotein lipase activity in human and guinea-pig placenta.

Human and guinea-pig placental activity was measured in tissue extracts and in medium in which tissue fragments have been incubated. Lipase activity was estimated from measured rates of release of 3H-labelled fatty acids from a 3H-labelled triacylglycerol substrate. Whole tissue lipase activity was 1.6 +/- 0.3 units/g (mean +/- SEM, mumol of unesterified fatty acid release/min) in the human, and 87.1 +/- 7.3 units/g in guinea-pig placental tissue. 70% of the human and 56% of the guinea-pig placental activity was lost on treating the tissues with cold acetone. Sodium chloride (0.75 M) decreased activity by 50% in extracts from both species. Lipase activity was released into media when placental fragments were incubated. The addition of heparin increased the release of lipase from human placenta but not significantly from that of the guniea-pig. Insulin had no effect on placental lipase activity from either species. It is concluded that the placentas of both species contain at least two lipases. One of these, which constituted a large of the total, had the characteristics of lipoprotein lipase.

Animals↗

PubMed1982

Cigarette smoke-induced cholesterol C-20, 22-desmolase inhibition in pregnancy.

In an attempt to demonstrate the physiological importance of cholesterol C-20, 22-desmolase regulation of pregnenolone formation in maternal cigarette smoking during pregnancy, the in vitro effect of cigarette smoke extract on corpus luteal and placental desmolase ability to cleave (26-14C) cholesterol to (14C) isocaproic acid, was studied. Using the reverse-isotope dilution technique, (14C) isocaproic acid was isolated and characterized. With the homogenates of corpora lutea of pregnancy (4 to 9 weeks gestation) the maximal inhibitory effect (98.3%) on desmolase efficiency became evident at equivalent of 4 cigarettes. In response to concentrations of the extract at 1/2, 1, 2 and 4 cigarette equivalents on the preparations of placentae (18 to 20 weeks gestation), a dose-dependent pattern of inhibitory effect was observed (29.1 to greater than 95.1%). These results are consistent with the interpretation that decreased supply of pregnenolone for the biosynthesis of progestational and oestrogenic hormones may be causally related to changes characteristic of cigarette-smoke induced pathologic state. It is suggested that similar studies directed towards alteration in biosynthetic capacity of steroidogenic enzymes may provide the basis for our understanding of molecular events initiated in response to the common insult.

Adult↗

PubMedDate not supplied

Mouse and rat placental cell lines express abundant amounts of laminin.

Placental cell lines derived from midgestation placentae of outbred mice and rats were evaluated for the expression of the extracellular matrix protein laminin. The murine cell line, which has not been previously reported, demonstrates morphological characteristics similar to those of the rat cell line. Placental cell lines grow vigorously both in vitro and when transplanted to the peritoneum of allogeneic hosts. When transplanted, placental cells form cyst-like structures (with acellular cores) suspended in the peritoneal fluid, and invade abdominal structures forming solid masses. Using immunohistology, laminin was identified within in vitro cultured cells, within cyst-like structures and their acellular cores, and as a major component of the extracellular matrix of solid masses. Laminin was also identified in the normal rat chorioallantoic placenta. Evaluation of extracts from in vitro cultured placental cells, transplanted placental cells, and the normal chorioallantoic placenta by electrophoresis and immunoblotting demonstrated that laminins were composed of two species with molecular weights of 400,000 (A-chain) and 200,000 (B-chains). Mouse and rat placental cell lines may be valuable for studying laminin biosynthesis and function in the developing placenta.

Animals↗

PubMed1995

A mouse placental immunoregulatory factor different from transforming growth factor beta.

Of the growth-promoting factors, transforming growth factor beta (TGF-beta) has been most clearly shown to act as a potent regulator of inflammation and immunity. It is highly suppressive for T and B lymphocyte proliferation, cytotoxic T lymphocyte generation, and lymphokine-activated killer cell development, as well as natural killer cell activity. Moreover, there is accumulating evidence that TGF-beta also may contribute to impaired immune surveillance of tumor development. In previous work, we isolated and described a 40 kD glycoprotein extracted from mouse placenta. This placental factor (PF) is also a potent immune modulator in vivo: it is highly inhibitory of secondary antibody responses as well as cellular responses, such as local graft-versus-host reactions. Because placenta has been shown to be a major source of TGF-beta and several reports have indicated an important role for TGF-beta in the immunosuppressive mechanisms taking place during the course of mammalian gestation, we have looked for the presence of TGF-beta in our placental factor preparations. Our results clearly indicate that they do not contain TGF-beta or TGF-beta-like molecules by the following criteria: (1) no inhibition of Mv-1 Lu cell proliferation at any dose tested; (2) no band detected by immunoblotting using different polyclonal reagents specific for TGF-beta 1; and (3) no activity retained on or eluted from an affinity column made of immobilized monoclonal antibody against TGF-beta 2. Aliquots of the same preparations retained their full immune inhibitory capacity in vivo throughout the various assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗