25 results on '"Rice GE"'
Search Results
2. Immunohistochemical localization of prostaglandin G/H synthase 1 and 2 in sheep placenta after glucocorticoid-induced and spontaneous labour
- Author
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McLaren, WJ, primary, Young, IR, additional, and Rice, GE, additional
- Published
- 2000
- Full Text
- View/download PDF
3. Parathyroid hormone-related protein(1-34) in gestational fluids and release from human gestational tissues
- Author
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Farrugia, W, primary, Ho, PW, additional, Rice, GE, additional, Moseley, JM, additional, Permezel, M, additional, and Wlodek, ME, additional
- Published
- 2000
- Full Text
- View/download PDF
4. Localisation and temporal changes in prostaglandin G/H synthase-1 and -2 content in ovine intrauterine tissues in relation to glucocorticoid-induced and spontaneous labour
- Author
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McLaren, WJ, primary, Young, IR, additional, and Rice, GE, additional
- Published
- 2000
- Full Text
- View/download PDF
5. Effect of bacterial endotoxin on the in vitro release of Type II phospholipase-A2 and prostaglandin E2 from human placenta
- Author
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Farrugia, W, primary, Nicholls, L, additional, and Rice, GE, additional
- Published
- 1999
- Full Text
- View/download PDF
6. Parathyroid hormone-related protein (PTHrP) mRNA splicing and parathyroid hormone/PTHrP receptor mRNA expression in human placenta and fetal membranes
- Author
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Curtis, NE, primary, Thomas, RJ, additional, Gillespie, MT, additional, King, RG, additional, Rice, GE, additional, and Wlodek, ME, additional
- Published
- 1998
- Full Text
- View/download PDF
7. Contribution of type II phospholipase A2 to in vitro phospholipase A2 enzymatic activity in human term placenta
- Author
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Rice, GE, primary, Wong, MH, additional, Farrugia, W, additional, and Scott, KF, additional
- Published
- 1998
- Full Text
- View/download PDF
8. The potential role of miRNAs and exosomes in chemotherapy in ovarian cancer.
- Author
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Alharbi M, Zuñiga F, Elfeky O, Guanzon D, Lai A, Rice GE, Perrin L, Hooper J, and Salomon C
- Subjects
- Animals, Antineoplastic Agents therapeutic use, DNA Damage, Disease Progression, Drug Resistance, Neoplasm genetics, Female, Humans, Membrane Transport Proteins metabolism, Ovarian Neoplasms metabolism, Ovarian Neoplasms pathology, Prognosis, Exosomes, MicroRNAs, Ovarian Neoplasms drug therapy, Ovarian Neoplasms genetics
- Abstract
Chemoresistance is one of the major obstacles in the treatment of cancer patients. It poses a fundamental challenge to the effectiveness of chemotherapy and is often linked to relapse in patients. Chemoresistant cells can be identified in different types of cancers; however, ovarian cancer has one of the highest rates of chemoresistance-related relapse (50% of patients within 5 years). Resistance in cells can either develop through prolonged cycles of treatment or through intrinsic pathways. Mechanistically, the problem of drug resistance is complex mainly because numerous factors are involved, such as overexpression of drug efflux pumps, drug inactivation, DNA repair mechanisms and alterations to and/or mutations in the drug target. Additionally, there is strong evidence that circulating miRNAs participate in the development of chemoresistance. Recently, miRNAs have been identified in exosomes, where they are encapsulated and hence protected from degradation. These miRNAs within exosomes (exo-miRNAs) can regulate the gene expression of target cells both locally and systemically. Exo-miRNAs play an important role in disease progression and can potentially facilitate chemoresistance in cancer cells. In addition, and from a diagnostic perspective, exo-miRNAs profiles may contribute to the development of predictive models to identify responder and non-responder chemotherapy. Such model may also be used for monitoring treatment response and disease progression. Exo-miRNAs may ultimately serve as both a predictive biomarker for cancer response to therapy and as a prognostic marker for the development of chemotherapy resistance. Therefore, this review examines the potential role of exo-miRNAs in chemotherapy in ovarian cancer.
- Published
- 2018
- Full Text
- View/download PDF
9. 2D-DIGE to identify proteins associated with gestational diabetes in omental adipose tissue.
- Author
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Oliva K, Barker G, Rice GE, Bailey MJ, and Lappas M
- Subjects
- Adipose Tissue chemistry, Adult, Diabetes, Gestational genetics, Electrophoresis, Gel, Two-Dimensional, Female, Humans, Mass Spectrometry, Omentum chemistry, Pregnancy, Proteins chemistry, Proteins genetics, Proteomics, Adipose Tissue metabolism, Diabetes, Gestational metabolism, Omentum metabolism, Proteins metabolism
- Abstract
Gestational diabetes mellitus (GDM) is a significant risk factor for the type 2 diabetes epidemic in many populations. Maternal adipose tissue plays a central role in the pathophysiology of GDM. Thus, the aim of this study was to determine the effect of GDM on the proteome of adipose tissue. Omental adipose tissue was obtained at the time of term Caesarean section from women with normal glucose tolerance (NGT) or GDM. 2D-difference gel electrophoresis (DIGE), followed by mass spectrometry, was used to identify protein spots (n = 6 patients per group). Western blotting was used for confirmation of six of the spot differences (n = 6 patients per group). We found 14 proteins that were differentially expressed between NGT and GDM adipose tissue (≥ 1.4-fold, P < 0.05). GDM was associated with an up-regulation of four proteins: collagen alpha-2(VI) chain (CO6A2 (COL6A2)), fibrinogen beta chain (FIBB (FGB)), lumican (LUM) and S100A9. On the other hand, a total of ten proteins were found to be down-regulated in adipose tissue from GDM women. These were alpha-1-antitrypsin (AIAT (SERPINA 1)), annexin A5 (ANXA5), fatty acid-binding protein, adipocyte (FABP4), glutathione S-transferase P (GSTP (GSTP1)), heat-shock protein beta-1 (HSP27 (HSPB1)), lactate dehydrogenase B chain (LDHB), perilipin-1 (PLIN1), peroxiredoxin-6 (PRX6 (PRDX6)), selenium-binding protein 1 (SBP1) and vinculin (VINC (VCL)). In conclusion, proteomic analysis of omental fat reveals differential expression of several proteins in GDM patients and NGT pregnant women. This study revealed differences in expression of proteins that are involved in inflammation, lipid and glucose metabolism and oxidative stress and added further evidence to support the role of visceral adiposity in the pathogenesis of GDM.
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- 2013
- Full Text
- View/download PDF
10. The effect of pre-existing maternal obesity on the placental proteome: two-dimensional difference gel electrophoresis coupled with mass spectrometry.
- Author
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Oliva K, Barker G, Riley C, Bailey MJ, Permezel M, Rice GE, and Lappas M
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- Adult, Body Mass Index, Cesarean Section, Female, Glucose Tolerance Test, Humans, Placenta cytology, Placenta metabolism, Pregnancy, Prenatal Exposure Delayed Effects, Proteomics methods, Maternal Nutritional Physiological Phenomena, Obesity metabolism, Placenta chemistry, Proteins analysis, Proteome analysis, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods, Two-Dimensional Difference Gel Electrophoresis methods
- Abstract
Our aim was to study the protein expression profiles of placenta obtained from lean and obese pregnant women with normal glucose tolerance at the time of term Caesarean section. We used two-dimensional difference gel electrophoresis (2D-DIGE), utilising narrow-range immobilised pH gradient strips that encompassed the broad pH range of 4-5 and 5-6, followed by MALDI-TOF mass spectrometry of selected protein spots. Western blot and quantitative RT-PCR (qRT-PCR) analyses were performed to validate representative findings from the 2D-DIGE analysis. Eight proteins were altered (six down-regulated and two up-regulated on obese placentas). Annexin A5 (ANXA5), ATP synthase subunit beta, mitochondria (ATPB), brain acid soluble protein 1 (BASP1), ferritin light chain (FTL), heterogeneous nuclear ribonucleoprotein C (HNRPC) and vimentin (VIME) were all lower in obese patients. Alpha-1-antitrypsin (A1AT) and stress-70 protein, mitochondrial (GRP75) were higher in obese patients. Western blot analysis of ANXA5, ATPB, FTL, VIME, A1AT and GRP75 confirmed the findings from the 2D-DIGE analysis. For brain acid soluble protein 1 and HNRPC, qRT-PCR analysis also confirmed the findings from the 2D-DIGE analysis. Immunohistochemical analysis was also used to determine the localisation of the proteins in human placenta. In conclusion, proteomic analysis of placenta reveals differential expression of several proteins in patients with pre-existing obesity. These proteins are implicated in a variety of cellular functions such as regulation of growth, cytoskeletal structure, oxidative stress, inflammation, coagulation and apoptosis. These disturbances may have significant implications for fetal growth and development.
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- 2012
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11. Advanced glycation endproducts mediate pro-inflammatory actions in human gestational tissues via nuclear factor-kappaB and extracellular signal-regulated kinase 1/2.
- Author
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Lappas M, Permezel M, and Rice GE
- Subjects
- Analysis of Variance, Biomarkers analysis, Butadienes pharmacology, Dinoprost analogs & derivatives, Dinoprost analysis, Dinoprost metabolism, Dinoprostone analysis, Dinoprostone metabolism, Extraembryonic Membranes enzymology, Extraembryonic Membranes immunology, Female, Humans, Interleukin-1 analysis, Interleukin-1 metabolism, Mitogen-Activated Protein Kinase 3 antagonists & inhibitors, NF-kappa B antagonists & inhibitors, Nitriles pharmacology, Phosphorylation, Placenta enzymology, Placenta immunology, Stimulation, Chemical, Sulfones pharmacology, Tissue Culture Techniques, Tumor Necrosis Factor-alpha analysis, Tumor Necrosis Factor-alpha metabolism, Extraembryonic Membranes metabolism, Glycation End Products, Advanced pharmacology, Mitogen-Activated Protein Kinase 3 metabolism, NF-kappa B metabolism, Placenta metabolism, Pregnancy metabolism
- Abstract
Processes of human labour include increased oxidative stress, formation of inflammatory mediators (e.g. cytokines) and uterotonic phospholipid metabolites (e.g. prostaglandins). In non-gestational tissues, advanced glycation endproducts (AGE) induce the expression of pro-inflammatory molecules through mitogen-activated protein kinase and nuclear factor kappaB (NF-kappaB)-dependent pathways. Thus, the aim of this study was to investigate the effects of AGE on 8-isoprostane (a marker of oxidative stress), pro-inflammatory cytokine and prostaglandin release in human gestational tissues, and to define the signalling pathways involved. Human placenta and gestational membranes (amnion and choriodecidua combined; n=5) were incubated in the absence or presence of AGE-BSA (0.25, 0.5, 1 and 2 mg/ml) for 18 h. AGE significantly increased in vitro release of tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-6, IL-8, prostaglandin (PG)E(2), PGF(2alpha) and 8-isoprostane from human placenta and gestational membranes. This was associated with a concomitant increase in NF-kappaB p65 activation and ERK 1/2 phosphorylation. AGE-stimulated 8-isoprostane, cytokine and prostaglandin production was significantly suppressed by the ERK 1/2 inhibitor U0126 and the NF-kappaB inhibitor BAY 11-7082. In conclusion, AGE mediates inflammatory actions in human gestational tissues. Protein kinases and the NF-kappaB pathway play an essential role in AGE signalling in human gestational tissues.
- Published
- 2007
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- View/download PDF
12. Release and regulation of leptin, resistin and adiponectin from human placenta, fetal membranes, and maternal adipose tissue and skeletal muscle from normal and gestational diabetes mellitus-complicated pregnancies.
- Author
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Lappas M, Yee K, Permezel M, and Rice GE
- Subjects
- Adiponectin, Adipose Tissue metabolism, Adult, Anti-Inflammatory Agents pharmacology, Case-Control Studies, Cytokines pharmacology, Dexamethasone pharmacology, Diabetes, Gestational metabolism, Estrogens pharmacology, Female, Glucose pharmacology, Hormones, Ectopic physiology, Humans, Insulin pharmacology, Intercellular Signaling Peptides and Proteins physiology, Leptin physiology, Lipopolysaccharides pharmacology, Muscle, Skeletal metabolism, Organ Culture Techniques, Pregnancy, Progesterone pharmacology, Resistin, Tetradecanoylphorbol Acetate pharmacology, Diabetes, Gestational physiopathology, Extraembryonic Membranes metabolism, Hormones physiology, Placenta metabolism
- Abstract
The aim of this study was to determine the release and regulation of leptin, resistin and adiponectin from human placenta and fetal membranes, and maternal subcutaneous adipose tissue and skeletal muscle obtained from normal and gestational diabetes mellitus (GDM)-complicated pregnancies at the time of Cesarean section. Tissue explants were incubated in the absence (basal control) or presence of 10 mug/ml lipopolysaccharide (LPS), 10, 20 or 40 ng/ml tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and IL-8, 1 microM phorbol myristate acetate, 10, 20 and 40 mM glucose, 0.1, 1 and 10 microM insulin and 0.1 1 and 10 microM dexamethasone, progesterone and estrogen. After an 18-h incubation, the medium was collected and the release of leptin, resistin and adiponectin was quantified by ELISA. Human gestational tissues and maternal tissues released immunoreactive leptin, resistin and adiponectin; however, there was no difference in the release of either resistin or adiponectin between normal pregnant women and women with gestational diabetes. The release of leptin was significantly higher in placenta, amnion and choriodecidua obtained from normal pregnant women compared with women with GDM. However, in maternal tissues, the situation was reversed, with adipose tissue and skeletal muscle obtained from women with GDM releasing significantly greater amounts of leptin. In adipose tissue and skeletal muscle the release of leptin was significantly greater in insulin-controlled GDM compared with diet-controlled GDM, and leptin release from adipose tissue was significantly correlated with maternal body mass index. In all tissues tested, there was no effect of incubation with LPS, IL-6, IL-8 or TNF-alpha on leptin, resistin or adiponectin release. PMA significantly increased the release of resistin from placenta and adipose tissue. Insulin increased placental resistin release, whereas the hormones dexamethasone, progesterone and estrogen significantly decreased placental resistin release. The data presented in this study demonstrate that dysregulation of leptin metabolism and/or function in the placenta may be implicated in the pathogenesis of GDM. Furthermore, resistin release is greatly affected by a variety of inflammatory mediators and hormones.
- Published
- 2005
- Full Text
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13. The expression of parathyroid hormone-related protein mRNA and immunoreactive protein in human amnion and choriodecidua is increased at term compared with preterm gestation.
- Author
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Curtis NE, Ho PW, King RG, Farrugia W, Moses EK, Gillespie MT, Moseley JM, Rice GE, and Wlodek ME
- Subjects
- Amnion chemistry, Amnion metabolism, Blotting, Northern, Chorion chemistry, Chorion metabolism, Decidua chemistry, Extraembryonic Membranes chemistry, Female, Gene Expression, Humans, Parathyroid Hormone metabolism, Parathyroid Hormone-Related Protein, Pregnancy, Proteins analysis, Proteins genetics, RNA, Messenger analysis, Radioimmunoassay, Decidua metabolism, Extraembryonic Membranes metabolism, Labor, Obstetric metabolism, Obstetric Labor, Premature metabolism, Proteins metabolism, RNA, Messenger metabolism
- Abstract
Parathyroid hormone-related protein (PTHrP) gene expression and/or immunoreactive protein have previously been identified in the uterus and intrauterine gestational tissues. The putative roles of PTHrP during pregnancy include vasodilatation, regulation of placental calcium transfer, uterine smooth muscle relaxation and normal fetal development. The aims of this study were 1) to determine the tissue-specific and temporal expression of PTHrP mRNA and immunoreactive protein in human gestational tissues collected at preterm and term; and 2) to determine the effect of labour on PTHrP expression by collecting these tissues from women undergoing elective caesarean section (before labour), intra-partum caesarean section during spontaneous-onset labour (during labour), and women with spontaneous labour and normal vaginal delivery (after labour). Total RNA and protein were extracted from placenta, amnion (over placenta and reflected) and choriodecidua for analysis by Northern blot (using a specific human PTHrP cDNA probe), and by N-terminal PTHrP RIA respectively. In amnion over placenta, reflected amnion and choriodecidua both PTHrP mRNA relative abundance and immunoreactive protein were significantly elevated at term compared with preterm (P < 0.01). At term, both PTHrP and its mRNA were significantly greater in amnion than in placenta and choriodecidua (P < 0.05). Also, both PTHrP and its mRNA were significantly elevated in amnion over placenta compared with reflected amnion (P < 0.05). The expression of PTHrP and its mRNA did not change in association with term labour or rupture of the fetal membranes, therefore this study provides no evidence for a specific PTHrP role in the onset and/or maintenance of term labour. However, the significant up-regulation of PTHrP mRNA and protein in the fetal membranes at term compared with preterm suggests an important role in late human pregnancy.
- Published
- 1997
- Full Text
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14. Release of Type II phospholipase A2 immunoreactivity and phospholipase A2 enzymatic activity from human placenta.
- Author
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Farrugia W, Rice GE, Wong MH, Scott KF, and Brennecke SP
- Subjects
- Female, Humans, Organ Culture Techniques, Phospholipases A2, Pregnancy, Pregnancy Trimester, Third, Time Factors, Isoenzymes metabolism, Phospholipases A metabolism, Placenta enzymology
- Abstract
The aim of this study was to determine whether Type II phospholipase A2 (PLA2) is released from late pregnant human placental tissue. Placental explants were incubated in vitro and the release of immunoreactive (ir) Type II PLA2 and PLA2 enzymatic activity into the medium was determined. Both irType II PLA2 and PL2 enzymatic activity accumulated in the incubation medium in a time-dependent manner (P < 0.0001). This release was not associated with a loss of cell membrane integrity, as indicated by measurement of the intracellular enzyme, lactate dehydrogenase, in the incubation medium. The concentration of irType II PLA2 and PLA2 enzyme activity present in incubation medium were significantly correlated (P < 0.01). Consistent with the hypothesis that Type II PLA2 may be store in secretory granules within human placental tissue, incubation in the presence of a membrane depolarising concentration of KCI (60 mM) caused the release of irType II PLA2 2.0-fold (P < 0.001). PLA2 enzyme activity released into the incubation medium displays biochemical characteristics consistent with those previously reported for secretory PLA2 isozymes, that is, a requirement for millimolar concentrations of calcium for optimal enzyme activity, inhibited by reducing agents, such as dithiothreitol and insensitive to heat inactivation. The data obtained in this study establish that irType PLA2 is released from term placenta, when incubated in vitro. The release of this extracellularly-active PLA2 isozyme may contribute to gestational and labour-associated increases in glycerophospholipid metabolism and prostaglandin formation.
- Published
- 1997
- Full Text
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15. Expression of prostaglandin G/H synthase-1 and -2 in ovine amnion and placenta following glucocorticoid-induced labour onset.
- Author
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McLaren WJ, Young IR, Wong MH, and Rice GE
- Subjects
- Amnion chemistry, Animals, Betamethasone pharmacology, Blotting, Western, Dinoprost analogs & derivatives, Dinoprost blood, Dinoprostone blood, Female, Fetal Blood chemistry, Glucocorticoids pharmacology, Hydrocortisone blood, Labor, Obstetric drug effects, Placenta chemistry, Pregnancy, Progesterone blood, Amnion enzymology, Isoenzymes, Labor, Obstetric metabolism, Placenta enzymology, Prostaglandin-Endoperoxide Synthases analysis, Sheep metabolism
- Abstract
Parturition in the sheep is preceded by an increase in the synthesis of prostaglandins by intrauterine tissues. Prostaglandin G/H synthase (PGHS) is the central enzyme involved in prostanoid production. Its expression is enhanced during late gestation in the ewe. Recent studies have identified two PGHS isozymes, termed PGHS-1 and PGHS-2. The labour-associated expression of the two isozymes of PGHS in the sheep has not been characterized. This study investigated the changes in expression of immunoreactive PGHS-1 and PGHS-2 in ovine amnion and placenta following glucocorticoid-induced labour. Ewes underwent surgery to implant fetal and maternal vascular cannulae and uterine electromyogram electrodes between 118 and 125 days of gestation. Fetal sheep were administered either the glucocorticoid betamethasone (n = 5) or saline (control n = 6) by direct transabdominal intrafetal injection. Ewes from the betamethasone-injected group were killed in the first stage of labour as indicated by uterine electromyographic activity. Ewes from the saline-injected group were killed at the same time to obtain age-matched control tissue. The time taken to euthanasia following induced-labour onset in the glucocorticoid-injected animals was 56.6 +/- 0.8 h post-injection. Plasma endocrine profiles in the maternal and fetal circulation following glucocorticoid injection were comparable to those observed following normal spontaneous delivery. At post-mortem, amnion and cotyledons were collected in liquid N2 and stored at -70 degrees C. Solubilized tissue extracts were prepared and analysed by Western blots using polyclonal antibodies to PGHS-1 and PGHS-2 isozymes. Fetal amnion contained PGHS-1 isozyme at day 133 of gestation, as demonstrated in the saline-injected animals. Slightly higher PGHS-1 immunoreactivity was observed following induced-labour onset, although this did not reach statistical significance (P > 0.05). PGHS-2 enzyme was not detectable in amnion. PGHS-2 expression was also not induced following labour onset. In contrast, PGHS-2 demonstrated enhanced expression following glucocorticoid-induced labour in ovine cotyledon. This tissue contained PGHS-1 enzyme, but immunoreactive levels were minimal and demonstrated limited regulation at labour. These data suggest that the previously reported rise in placental PG production at term in the sheep is predominantly due to increased expression of the PGHS-2 isozyme. This suggests that PGHS-2 contributes to PG production at term labour in sheep or is induced by the mechanisms controlling ovine parturition. PGHS-1 isozyme is produced constitutively in ovine amnion and may contribute to the gestational increase in PG formation by intrauterine tissues.
- Published
- 1996
- Full Text
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16. Labour-associated increase in interleukin-1 alpha release in vitro by human gestational tissues.
- Author
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Laham N, Brennecke SP, Bendtzen K, and Rice GE
- Subjects
- Amnion drug effects, Amnion metabolism, Culture Techniques, Dose-Response Relationship, Drug, Extraembryonic Membranes drug effects, Female, Humans, Interleukin-1 blood, Labor, Obstetric blood, Placenta drug effects, Pregnancy, Extraembryonic Membranes metabolism, Interleukin-1 metabolism, Labor, Obstetric immunology, Lipopolysaccharides pharmacology, Placenta metabolism
- Abstract
The aims of this study were to investigate the concentration and release of interleukin-1 alpha (IL-1 alpha) at the time of human term labour, and to study the regulation of IL-1 alpha release from human gestational tissue explants by bacterial endotoxin. Immunoreactive IL-1 alpha concentrations in maternal plasma, amniotic fluid and conditioned media from human amniotic fluid and conditioned media from human amniotic, choriodecidual and placental explants were quantified before and after spontaneous term labour-onset and delivery. Furthermore, the effects of a bacterial endotoxin, lipopolysaccharide (LPS), on the release of IL-1 alpha from human gestational tissue explants over a time course of 24 h (n = 3) and LPS concentrations ranging from 10-10(7) pg/ml (n = 3) were investigated. IL-1 alpha concentrations in maternal plasma and amniotic fluid did not change significantly with spontaneous term labour-onset. In contrast, IL-1 alpha was released in detectable amounts from human amniotic and choriodecidual explants only in association with term labour-onset and delivery. Similarly, placental release of IL-1 alpha was increased significantly in explant cultures in association with term labour-onset and delivery. LPS increased IL-1 alpha release significantly only from human placental explants from both term not-in-labour and term after-labour tissues. The data demonstrate differential regulation of IL-1 alpha release from human gestational tissues in association with labour and LPS treatment and the observations support the hypothesis that the labour-associated increase in IL-1 alpha release from the fetal membranes is independent of exposure to bacterial endotoxin.
- Published
- 1996
- Full Text
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17. Differential release of interleukin-6 from human gestational tissues in association with labour and in vitro endotoxin treatment.
- Author
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Laham N, Brennecke SP, Bendtzen K, and Rice GE
- Subjects
- Cesarean Section, Dose-Response Relationship, Drug, Enzyme-Linked Immunosorbent Assay, Escherichia coli, Extraembryonic Membranes drug effects, Female, Humans, In Vitro Techniques, Labor Onset, Lipopolysaccharides pharmacology, Placenta drug effects, Pregnancy, Time Factors, Amniotic Fluid metabolism, Extraembryonic Membranes metabolism, Interleukin-6 metabolism, Labor, Obstetric metabolism, Placenta metabolism
- Abstract
In this study, we quantified interleukin-6 (IL-6) concentrations in amniotic fluid at term and preterm labour, and determined the gestational tissue source of IL-6. In addition, aspects of the regulatory mechanisms involved in IL-6 release at the time of term labour and in response to bacterial endotoxin, lipopolysaccharide (LPS), have been established. IL-6 concentrations were 2-fold higher in amniotic fluid collected at term compared with preterm gestation, with an additional 2-fold increase in association with term labour. IL-6 was released from all choriodecidual and placental explants but was detected in only 33% of amniotic explant cultures of tissues obtained before labour onset. In contrast, IL-6 was detected in all amniotic, choriodecidual and placental cultures of tissues obtained after term labour onset and delivery, and the mean IL-6 release was significantly higher than that measured in explant cultures of both amniotic (80-fold increase, P < 0.0001) and choriodecidual (3-fold increase, P < 0.02) but not placental explants taken at the time of elective Caesarean section at term before labour onset. LPS significantly (P < 0.05) increased the release of IL-6 from human choriodecidual and placental explants but not amniotic explants, in a time- and dose-dependent manner. IL-6 is a physiological constituent of amniotic fluid and its production by gestational tissues is differentially regulated by LPS and spontaneous labour onset and delivery.
- Published
- 1996
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18. Characterisation of acyltransferase activity in ovine placental tissue during pregnancy and at the time of labour.
- Author
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Wong MH and Rice GE
- Subjects
- Acyltransferases metabolism, Animals, Arachidonic Acid metabolism, Eicosanoids metabolism, Female, Labor, Obstetric metabolism, Pregnancy, Time Factors, Placenta enzymology, Sheep metabolism
- Abstract
Although it is well established that the formation of eicosanoids by ovine intrauterine tissues increases during pregnancy and at the time of labour, the biochemical mechanisms involved remain to be clearly established. In this study, we tested the hypothesis that the gestational and labour-associated increases in eicosanoid formation are associated with a reduction in the activity of the reacylating enzyme, acyl Coenzyme A lysophosphatide acyltransferase (LAT). To evaluate this proposal, in vitro LAT activity was quantified in ovine placenta (cotyledons) obtained during pregnancy (85-147 days of gestation and at the time of labour). Ovine placental LAT increased from 1.81 +/- 0.06 nmol/min per mg protein at 85 days of gestation to 2.34 +/- 0.10 nmol/min per mg protein at 142 days of gestation (P < 0.005; n = 15). The apparent Km did not vary significantly between the 85- and 142-day groups. Vmax, however, was significantly greater in the late-gestation group (2.98 +/- 0.02 nmol/min per mg protein) than in the mid-gestation group (2.38 +/- 0.13 nmol/min per mg protein, P < 0.05). In association with labour, placental LAT activity decreased by 16% (1.96 +/- 0.13 nmol/min per mg protein) when compared with that observed in tissue obtained from the non-labouring ewe (P < 0.01). The data obtained are consistent with the hypothesis that changes in LAT activity in ovine placenta do not contribute to the gestational increase in prostaglandin formation, but a contribution to the labour-associated increase in non-esterified arachidonic acid availability and eicosanoid formation cannot be negated.
- Published
- 1996
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19. Gestational- and labour-associated changes in the relative abundance of prostaglandin G/H synthase-1 and -2 mRNA in ovine placenta.
- Author
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Rice GE, Freed KA, Aitken MA, and Jacobs RA
- Subjects
- Animals, DNA genetics, Enzyme Induction, Female, Isoenzymes genetics, Pregnancy, Prostaglandin-Endoperoxide Synthases genetics, Sheep genetics, Species Specificity, Vertebrates genetics, Isoenzymes biosynthesis, Labor, Obstetric metabolism, Placenta enzymology, Pregnancy, Animal metabolism, Prostaglandin-Endoperoxide Synthases biosynthesis, RNA, Messenger analysis, Sheep physiology
- Abstract
The aim of this study was to establish the gestational- and labour-associated variation in the relative abundance of prostaglandin synthase-1 (PGHS-1) and prostaglandin synthase-2 (PGHS-2) mRNA in ovine placenta (cotyledons). Cotyledons were collected from non-labouring ewes at 40-145 days of gestation (n = 25) and from ewes in active labour (145-147 days, n = 5). The relative abundance of PGHS-1 and PGHS-2 mRNA transcripts was determined by Northern blot analysis and laser densitometry, using a 2.3 kb sheep and a 1.2 kb mouse cDNA probe respectively. Data were expressed as a ratio of PGHS transcript hybridization/18S rRNA hybridization. During pregnancy, the relative abundance of PGHS-2 mRNA increased sevenfold, from 0.19 +/- 0.04 at 40-85 days (n = 5) to 1.39 +/- 0.05 at 140-145 days (n = 4) (P < 0.01). PGHS-1 mRNA relative abundance did not change significantly (P > 0.05) during gestation. Neither PGHS-1 nor PGHS-2 mRNA relative abundance changed significantly in association with labour onset at term (n = 5) when compared with the relative abundance observed at 140-145 days (n = 4) (P > 0.05). The data obtained in this study are consistent with the hypothesis that PGHS-1 is constitutively expressed in ovine placenta during pregnancy and at the time of labour, and that PGHS-2 is induced during the second half of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1995
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20. Regulation of oxytocin secretion by the ovine corpus luteum: effect of activators of protein kinase C.
- Author
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Hirst JJ, Rice GE, Jenkin G, and Thorburn GD
- Subjects
- Animals, Bucladesine pharmacology, Calcimycin pharmacology, Corpus Luteum drug effects, Diglycerides pharmacology, Dose-Response Relationship, Drug, Enzyme Activation physiology, Female, In Vitro Techniques, Phorbol 12,13-Dibutyrate pharmacology, Platelet Activating Factor antagonists & inhibitors, Pyrimidinones pharmacology, Tetradecanoylphorbol Acetate pharmacology, Thiazoles pharmacology, Type C Phospholipases pharmacology, Corpus Luteum physiology, Oxytocin metabolism, Protein Kinase C metabolism, Sheep physiology
- Abstract
The effect of protein kinase C activation and dibutyryl cyclic AMP on oxytocin secretion by ovine luteal tissue slices was investigated. Several putative regulators of luteal oxytocin secretion were also examined. Oxytocin was secreted by luteal tissue slices at a basal rate of 234.4 +/- 32.8 pmol/g per h (n = 24) during 60-min incubations. Activators of protein kinase C: phorbol 12, 13-dibutyrate (n = 8), phorbol 12-myristate, 13-acetate (n = 4) and 1,2-didecanoylglycerol (n = 5), caused a dose-dependent stimulation of oxytocin secretion in the presence of a calcium ionophore (A23187; 0.2 mumol/l). Phospholipase C (PLC; 50-250 units/l) also caused a dose-dependent stimulation of oxytocin secretion by luteal slices. Phospholipase C-stimulated oxytocin secretion was potentiated by the addition of an inhibitor of diacylglycerol kinase (R59 022; n = 4). These data suggest that the activation of protein kinase C has a role in the stimulation of luteal oxytocin secretion. The results are also consistent with the involvement of protein kinase C in PLC-stimulated oxytocin secretion. The cyclic AMP second messenger system does not appear to be involved in the control of oxytocin secretion by the corpus luteum.
- Published
- 1990
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21. Gestational changes in prostaglandin synthase activity of ovine cotyledonary microsomes.
- Author
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Rice GE, Wong MH, and Thorburn GD
- Subjects
- Animals, Arachidonic Acid, Arachidonic Acids metabolism, Female, Pregnancy, Time Factors, Microsomes enzymology, Placenta enzymology, Pregnancy, Animal physiology, Prostaglandin-Endoperoxide Synthases metabolism, Sheep physiology
- Abstract
The capacity of cotyledonary microsomes, prepared from pregnant ewes (20-145 days of gestation), to metabolize exogenous arachidonic acid was quantified using a radiolabel technique. During gestation, the capacity of microsomes to metabolize arachidonic acid increased 25-fold, from 0.36 +/- 0.06 mumol arachidonic acid/incubation (n = 8) at less than 100 days of gestation to 9.06 +/- 1.02 mumol arachidonic acid/incubation at 130-145 days of gestation (n = 5; P less than 0.05). Arachidonic acid was metabolized to prostaglandin E2 and F2 alpha, as determined by thin-layer chromatography and reverse-phase high performance liquid chromatography. The profile of prostaglandins synthesized by cotyledonary microsomes did not change throughout gestation. These data suggest that the increase in cotyledonary prostaglandin synthesis that occurs during late gestation and at term may reflect an increase in the tissue content of prostaglandin H2 synthase.
- Published
- 1988
- Full Text
- View/download PDF
22. Comparison of particle-associated progesterone and oxytocin in the ovine corpus luteum.
- Author
-
Rice GE, Jenkin G, and Thorburn GD
- Subjects
- Animals, Cell Membrane metabolism, Centrifugation, Density Gradient, Female, Sheep, Corpus Luteum metabolism, Oxytocin metabolism, Progesterone metabolism
- Abstract
The subcellular distribution of progesterone and oxytocin within the ovine corpus luteum was investigated using differential and density gradient centrifugation. Progesterone and oxytocin were associated with particles which sedimented to a density of 1.049-1.054 g/ml and 1.054-1.061 g/ml respectively. Particle-associated progesterone did not, however, display physical or biochemical characteristics consistent with its storage within secretory granules. When particle-associated progesterone was incubated in HEPES buffer at 37 degrees C, 70% of the total progesterone was recovered in the incubation medium. The remaining stable particle-associated progesterone was not affected by treatments which stimulated oxytocin release and which have been shown to cause the release of peptides and biogenic amines from secretory granules. These results suggest that particle-associated progesterone represents the intercalation of progesterone into cell membranes and they do not support the hypothesis that progesterone is stored, in a protein-bound form, in luteal secretory granules.
- Published
- 1986
- Full Text
- View/download PDF
23. Characterization of particle-associated choriomammotrophin and progesterone in ovine placentomes.
- Author
-
Rice GE and Thorburn GD
- Subjects
- Animals, Cell Fractionation, Centrifugation, Density Gradient, Cytoplasmic Granules analysis, Female, Microscopy, Electron, Osmolar Concentration, Placenta ultrastructure, Pregnancy, Placenta analysis, Placental Lactogen analysis, Progesterone analysis, Sheep metabolism
- Abstract
The subcellular distribution and compartmentalization of choriomammotrophin (CM) and progesterone within ovine placentomes was investigated using differential and density gradient centrifugation techniques. Approximately 67% of placental CM and 45% of progesterone was associated with subcellular particles. The 10,000 g particulate fraction contained the highest specific activity of both CM and progesterone (19.1 +/- 3.8 (S.E.M.) micrograms/mg and 71.5 +/- 9.2 pmol/mg protein respectively). This fraction was also shown to contain electron-dense granules with morphology similar to that of hormone-containing secretory granules isolated from other endocrine tissues. Particle-associated CM sedimented to a density of 1.051-1.054 g/ml in colloidal silica gradients and displayed physicochemical characteristics consistent with its storage in secretory granules. During in-vitro incubations, particle-associated CM was stable for up to 90 min, but dissociated when incubated in hypoosmotic medium. Particulate progesterone, which was also present in the CM-rich fraction and was stable for up to 90 min of incubation, was not affected by decreasing the osmolality of the incubation medium. These data suggest that ovine CM (but not progesterone) is stored within a population of secretory granules located within placentomes.
- Published
- 1986
- Full Text
- View/download PDF
24. Ovine allantoic fluid inhibition of prostaglandin synthesis in cotyledonary microsomes.
- Author
-
Rice GE, Wong MH, Ralph MM, and Thorburn GD
- Subjects
- Animals, Arachidonic Acids pharmacology, Dinoprost, Dinoprostone, Female, Microsomes drug effects, Phospholipases A pharmacology, Phospholipases A2, Allantois metabolism, Body Fluids metabolism, Extraembryonic Membranes metabolism, Microsomes metabolism, Placenta metabolism, Prostaglandins E biosynthesis, Prostaglandins F biosynthesis, Sheep physiology
- Abstract
Inhibition of microsomal prostaglandin (PG) biosynthesis by allantoic fluid, obtained from ewes at 80-120 days of gestation, was examined. Inhibition of cotyledonary microsomal PGE2 and PGF2 alpha biosynthesis by lyophilized allantoic fluid occurred in a dose-dependent manner. The concentration of allantoic fluid required to inhibit PGE2 and PGF2 alpha production by 50% averaged 17.9 +/- 3.2 (S.E.M.) mg dry weight/ml (n = 5). Microsomal PG biosynthesis was markedly enhanced by the addition of arachidonic acid (30 mumol/l). Synthesis of PGE2 and PGF2 alpha was increased to 245 +/- 65% and 184 +/- 14% of control (P less than 0.05, n = 5) respectively. Treatment of cotyledonary microsomes with porcine phospholipase A2 (PLA2; 0.125 units/ml) also stimulated PG synthesis, PGE2 increasing to 216 +/- 27% and PGF2 alpha to 172 +/- 14% of control (P less than 0.05, n = 5) respectively. Allantoic fluid (20 mg dry weight/ml) inhibited arachidonic acid-stimulated PG synthesis (PGE2 by 48.6 +/- 13.8% and PGF2 alpha by 44.2 +/- 7.7%) and PLA2-stimulated PG synthesis (PGE2 by 60.6 +/- 11.6% and PGF2 alpha by 74.8 +/- 8.5%). Allantoic fluid, however, did not affect PLA2-stimulated release of arachidonic acid from microsomes, thus negating the possibility that allantoic fluid suppresses PG synthesis by inhibiting PLA2 activity. These data indicate that allantoic fluid inhibits PG production at the level of PG synthase enzymes. Prostaglandin inhibitor(s) in allantoic fluid may play a role in maintaining uterine quiescence throughout gestation and its withdrawal, at term, may be involved in the initiation of labour.
- Published
- 1987
- Full Text
- View/download PDF
25. Biophysical characteristics of oxytocin secretory granules isolated from ovine corpora lutea.
- Author
-
Rice GE
- Subjects
- Animals, Biophysical Phenomena, Biophysics, Cell Fractionation, Centrifugation, Isopycnic, Corpus Luteum drug effects, Corpus Luteum metabolism, Cytoplasmic Granules drug effects, Cytoplasmic Granules metabolism, Female, Pituitary Gland, Posterior ultrastructure, Potassium Chloride pharmacology, Sheep, Corpus Luteum ultrastructure, Cytoplasmic Granules ultrastructure, Oxytocin metabolism
- Abstract
Luteal oxytocin-containing secretory granules have been isolated and characterized in terms of their physicochemical parameters. The isopynic sedimentation density (1.03 +/- 0.003 g/ml) and sedimentation coefficient (1670 S, 0.32 mol sucrose/l, 4 degrees C) of these granules have been estimated. Based upon these estimates, the average vesicle diameter (258 +/- 17 nm) and vesicle weight (9.92 +/- 0.67 fg/vesicle) were calculated. The exchangeable water content (58.2%) of these granules was determined using density gradients prepared with deuterium oxide. Luteal oxytocin-containing granules displayed similar physicochemical characteristics to those reported for neurohypophysial peptide-containing granules, with the exception of particle size. Luteal granules were 1.3 times greater in diameter than neurohypophysial granules.
- Published
- 1988
- Full Text
- View/download PDF
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