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Publication
Journal: Journal of Pharmacology and Experimental Therapeutics
August/11/2008
Abstract
Lipopolysaccharide (LPS) produces prostaglandins (PGs) concomitant to eliciting macrophage migration. We evaluated the role of PGs in initiating the migration of macrophages, especially focusing on PGD(2) and PGE(2). In RAW264.7 macrophages, cyclooxygenase (COX)-2 inhibitor, CAY10404 [3-(4-methylsulphonylphenyl)-4-phenyl-5-trifluoromethylisoxazole], completely inhibited LPS-mediated migration at 4 h (early phase) but only partially inhibited the migration at 8 h (late phase), suggesting the presence of PG-dependent and -independent pathways. In the early phase, LPS up-regulated mRNA expressions of COX-2, hematopoietic PGD synthase (H-PGDS), and microsomal-PGE synthase 1, increasing PGD(2) and PGE(2) substantially. The chemoattractant receptor-homologous molecule expressed on Th2 lymphocytes (CRTH2) agonist, DK-PGD(2) (13-14-dihydro-15-keto-PGD(2)), and the <em>EP</em>4 agonist, ONO-AE1-329 (16-{3-methoxymethyl}phenyl-omega-tetranor-3,7-dithia-prostaglandin E(1)), but not selective agonists of D prostanoid receptor, E prostanoid receptor (<em>EP</em>) 2, or <em>EP</em>3, stimulated random migration (chemokinesis). In peritoneal macrophages from CRTH2-deficient and H-PGDS-deficient mice, LPS-mediated migration was significantly inhibited at either early or late phases of the migration. The H-PGDS inhibitor, HQL-79 [4-(diphenylmethoxy)-1-[3-(1H-tetrazol-5-yl)propyl-piperidine]], partially inhibited the migration of the RAW264.7 macrophage in both phases. These results suggest the importance of the PGD(2)/CRTH2 pathway in LPS-mediated migration of macrophages. In the late phase of migration, LPS up-regulated monocyte chemoattractant protein (MCP)-1 mRNA. The CC chemokine receptor (CCR2) antagonist, RS102895 [1'-[2-[4-(trifluoromethyl)phenyl]ethyl]-spiro[4H-3,1-benzoxazine-4,4'-piperidin]-2(1H)-one], inhibited LPS-mediated migration in the late phase without affecting the early phase. ONO-AE1-329, but not DK-PGD(2), up-regulated MCP-1 mRNA. Taken together, LPS stimulation of chemokinesis or chemotaxis, or both, occurs in macrophages via PGD(2) and PGE(2) in tandem arrangement; i.e., 1) LPS stimulates prostaglandin signaling, initiating early migration through the PGD(2)/CRTH2 and PGE(2)/<em>EP</em>4 signaling pathways; and 2) LPS leads induction of MCP-1, which contributes to later phase migration of the macrophages through the PGE(2)/<em>EP</em>4 pathway.
Publication
Journal: Cell adhesion and communication
March/2/1995
Abstract
Recently we have demonstrated that a 40kD human epithelium-specific glycoprotein exhibit the features of a homophilic cell-cell adhesion molecule, when expressed in transfected murine cells. We suggested the name Ep-CAM for this molecule (Litvinov et al., J. Cell Biol., 125: 437-446). Here we investigate the possible biological function of Ep-CAM in its natural environment--cells of epithelial origin. Immunolocalization of Ep-CAM in tissues and in cultures of epithelial/carcinoma cells showed that the majority of the Ep-CAM molecules are localized at cell-cell boundaries, predominantly along the whole lateral domain of polarized cells. In vitro, on single cells in suspension, the Ep-CAM molecules are present on the entire cell surface, and when the single cells grow attached, Ep-CAM is present at their pseudo-apical domain. During formation of intercellular contacts by such single cells, the majority of the Ep-CAM molecules are redistributed from the pseudoapical to the lateral domain of the cell membrane. Attachment of cells to the substrate does not cause redistribution of the molecules to the site of substrate attachment irrespective of the adhesive substrate (fibronectin, collagens, laminin, EHS-matrigel were tested). The monoclonal antibody 323/A3, reactive with the extracellular domain of the Ep-CAM molecule, has a strong negative effect on the aggregating behavior of COV362 ovarian carcinoma cells and RC-6 immortalized mammary epithelial cells. The mAb affected cell aggregation in both cell lines in the presence of Ca++, but with RC-6 cells the effect was more pronounced in low-calcium medium. The effects of the 323/A3 mAb on the already established intercellular contacts was not significant. The data presented demonstrate that the Ep-CAM molecules are functionally active in the epithelial and carcinoma cells tested, are capable of mediating Ca(++)-independent intercellular adhesions, and are not likely to be involved in cell-substrate adhesion.
Publication
Journal: Experimental Cell Research
June/3/2003
Abstract
Various adhesion molecules play an important role in defining cell fate and maintaining tissue integrity. Therefore, cross-signaling between adhesion receptors should be a common phenomenon to support the orchestrated changes of cells' connections to the substrate and to the neighboring cells during tissue remodeling. Recently, we have demonstrated that the epithelial cell adhesion molecule Ep-CAM negatively modulates cadherin-mediated adhesions in direct relation to its expression levels. Here, we used E-cadherin/alpha-catenin chimera constructs to define the site of Ep-CAM's negative effect on cadherin-mediated adhesions. Murine L-cells transfected with either E-cadherin/alpha-catenin fusion protein, or E-cadherin fused to the carboxy-terminal half of alpha-catenin, were subsequently supertransfected with an inducible Ep-CAM construct. Introduction of Ep-CAM altered the cell's morphology, weakened the strength of cell-cell interactions, and decreased the cytoskeleton-bound fraction of the cadherin/catenin chimeras in both cell models. Furthermore, expression of Ep-CAM induced restructuring of F-actin, with changes in thickness and orientation of the actin filaments. The results showed that Ep-CAM affects E-cadherin-mediated adhesions without involvement of beta-catenin by disrupting the link between alpha-catenin and F-actin. The latter is likely achieved through remodeling of the actin cytoskeleton by Ep-CAM, possibly through pp120.
Publication
Journal: Cancer and Metastasis Reviews
April/1/2012
Abstract
Prostaglandins are lipid compounds that mediate many physiological effects. Prostaglandin E2 (PGE(2)) is the most abundant prostanoid in the human body, and synthesis of PGE(2) is driven by cyclooxygenase enzymes including COX-2. Both elevated expression of COX-2 and increased PGE(2) levels have been associated with many cancers including breast cancer. PGE(2) exerts its effect by binding to the E series of prostaglandin receptors (EP) which are G protein-coupled receptors. Four EP receptor subtypes exist, EPEP receptors have been shown to play a role in breast and other malignancies and in cancer metastasis. The role of each EP receptor in malignant behavior is complex and involves the interplay of EP receptor signaling on the tumor cell, on stromal cells, and on host immune effector cells. While preclinical and epidemiological data support the use of nonsteroidal anti-inflammatory drugs and selective COX-2 inhibitors (COXibs) for the prevention and treatment of malignancy, toxicities due to COXibs as well as less than promising results from clinical trials have laboratories seeking alternative targets. As knowledge concerning the role of EP receptors in cancer grows, so does the potential for exploiting EP receptors as therapeutic targets for the treatment or prevention of cancer and cancer metastasis.
Publication
Journal: British Journal of Pharmacology
May/19/2010
Abstract
Identification of the primary products of cyclo-oxygenase (COX)/prostaglandin synthase(s), which occurred between 1958 and 1976, was followed by a classification system for prostanoid receptors (DP, EP(1), EP(2) ...) based mainly on the pharmacological actions of natural and synthetic agonists and a few antagonists. The design of potent selective antagonists was rapid for certain prostanoid receptors (EP(1), TP), slow for others (FP, IP) and has yet to be achieved in certain cases (EP(2)). While some antagonists are structurally related to the natural agonist, most recent compounds are 'non-prostanoid' (often acyl-sulphonamides) and have emerged from high-throughput screening of compound libraries, made possible by the development of (functional) assays involving single recombinant prostanoid receptors. Selective antagonists have been crucial to defining the roles of PGD(2) (acting on DP(1) and DP(2) receptors) and PGE(2) (on EP(1) and EP(4) receptors) in various inflammatory conditions; there are clear opportunities for therapeutic intervention. The vast endeavour on TP (thromboxane) antagonists is considered in relation to their limited pharmaceutical success in the cardiovascular area. Correspondingly, the clinical utility of IP (prostacyclin) antagonists is assessed in relation to the cloud hanging over the long-term safety of selective COX-2 inhibitors. Aspirin apart, COX inhibitors broadly suppress all prostanoid pathways, while high selectivity has been a major goal in receptor antagonist development; more targeted therapy may require an intermediate position with defined antagonist selectivity profiles. This review is intended to provide overviews of each antagonist class (including prostamide antagonists), covering major development strategies and current and potential clinical usage.
Publication
Journal: International Journal of Molecular Sciences
April/23/2014
Abstract
Biofilms are communities of microorganisms embedded in extracellular polymeric substances (EPS) matrix. Bacteria in biofilms demonstrate distinct features from their free-living planktonic counterparts, such as different physiology and high resistance to immune system and antibiotics that render biofilm a source of chronic and persistent infections. A deeper understanding of biofilms will ultimately provide insights into the development of alternative treatment for biofilm infections. The opportunistic pathogen Pseudomonas aeruginosa, a model bacterium for biofilm research, is notorious for its ability to cause chronic infections by its high level of drug resistance involving the formation of biofilms. In this review, we summarize recent advances in biofilm formation, focusing on the biofilm matrix and its regulation in P. aeruginosa, aiming to provide resources for the understanding and control of bacterial biofilms.
Publication
Journal: European Journal of Nuclear Medicine and Molecular Imaging
December/2/2015
Abstract
OBJECTIVE
The follow-up of glioblastoma patients after radiochemotherapy with conventional MRI can be difficult since reactive alterations to the blood-brain barrier with contrast enhancement may mimic tumour progression (i.e. pseudoprogression, PsP). The aim of this study was to assess the clinical value of O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) PET in the differentiation of PsP and early tumour progression (EP) after radiochemotherapy of glioblastoma.
METHODS
A group of 22 glioblastoma patients with new contrast-enhancing lesions or lesions showing increased enhancement (>25 %) on standard MRI within the first 12 weeks after completion of radiochemotherapy with concomitant temozolomide (median 7 weeks) were additionally examined using amino acid PET with (18)F-FET. Maximum and mean tumour-to-brain ratios (TBRmax, TBRmean) were determined. (18)F-FET uptake kinetic parameters (i.e. patterns of time-activity curves, TAC) were also evaluated. Classification as PsP or EP was based on the clinical course (no treatment change at least for 6 months), follow-up MR imaging and/or histopathological findings. Imaging results were also related to overall survival (OS).
RESULTS
PsP was confirmed in 11 of the 22 patients. In patients with PsP, (18)F-FET uptake was significantly lower than in patients with EP (TBRmax 1.9 ± 0.4 vs. 2.8 ± 0.5, TBRmean 1.8 ± 0.2 vs. 2.3 ± 0.3; both P < 0.001) and presence of MGMT promoter methylation was significantly more frequent (P = 0.05). Furthermore, a TAC type II or III was more frequently present in patients with EP (P = 0.04). Receiver operating characteristic analysis showed that the optimal (18)F-FET TBRmax cut-off value for identifying PsP was 2.3 (sensitivity 100 %, specificity 91 %, accuracy 96 %, AUC 0.94 ± 0.06; P < 0.001). Univariate survival analysis showed that a TBRmax <2.3 predicted a significantly longer OS (median OS 23 vs. 12 months; P = 0.046).
CONCLUSIONS
(18)F-FET PET may facilitate the diagnosis of PsP following radiochemotherapy of glioblastoma.
Publication
Journal: Journal of Bacteriology
October/23/2000
Abstract
Vibrio parahaemolyticus is a ubiquitous, gram-negative marine bacterium that undergoes phase variation between opaque and translucent colony morphologies. The purpose of this study was to determine the factor(s) responsible for the opaque and translucent phenotypes and to examine cell organization within both colony types. Examination of thin sections of ruthenium red-stained bacterial cells by electron microscopy revealed a thick, electron-dense layer surrounding the opaque cells that was absent in preparations from translucent strains. Extracellular polysaccharide (EPS) material was extracted from both opaque and translucent strains, and the opaque strain was shown to produce abundant levels of polysaccharide, in contrast to the translucent strain. Compositional analysis of the EPS identified four major sugars: glucose, galactose, fucose, and N-acetylglucosamine. Confocal scanning laser microscopy was used to investigate cell organization within opaque and translucent colonies. Cells within both types of colonies exhibited striking organization; rod-shaped cells were aligned parallel to one another and perpendicular to the agar surface throughout the depth of the colony. Cells within translucent colonies appeared more tightly packed than cells in opaque colonies. In addition, a dramatic difference in the structural integrity of these two colony types was observed. When colonies were perturbed, the cell organization of the translucent colonies was completely disrupted while the organization of the opaque colonies was maintained. To our knowledge, this study represents the first description of how cells are organized in the interior of a viable bacterial colony. We propose that the copious amount of EPS produced by the opaque strain fills the intercellular space within the colony, resulting in increased structural integrity and the opaque phenotype.
Publication
Journal: Psychopharmacology
July/23/2003
Abstract
BACKGROUND
Switching patients from one antipsychotic to another can lead to tolerability problems or transient symptom exacerbations. It is important to compare switching strategies to determine which methods produce the best possible patient outcomes.
OBJECTIVE
To investigate the efficacy, safety and tolerability of three dosing strategies for switching chronic, stable patients with schizophrenia from current oral antipsychotic monotherapy to once-daily oral aripiprazole monotherapy.
METHODS
Patients in this 8-week, open-label, outpatient study were randomized to: 1). immediate initiation of 30 mg/day aripiprazole with simultaneous immediate discontinuation of current antipsychotic; 2). immediate initiation of 30 mg/day aripiprazole while tapering off current antipsychotic over 2 weeks; or 3). up-titrating aripiprazole to 30 mg/day over 2 weeks, while simultaneously tapering off current antipsychotic. Efficacy assessments included PANSS, CGI-S, and CGI-I scores. Safety assessments included: adverse events (AEs) recording, evaluation of extrapyramidal symptoms (EPS), vital signs, ECG, and clinical laboratory tests.
RESULTS
Efficacy with aripiprazole was maintained during the study with numerical improvements compared with baseline in all three groups. The overall incidence of AEs was broadly comparable across all groups, and AEs were generally mild to moderate in severity and time-limited. Discontinuations due to AEs were comparable across the groups. No deterioration in EPS occurred in any group. The reduction in body weight and plasma prolactin levels following switch to aripiprazole were comparable across the three groups.
CONCLUSIONS
Any of the three strategies evaluated can be used safely for switching patients to aripiprazole from antipsychotic monotherapy. Furthermore, patients' symptoms may continue to improve after switching to aripiprazole.
Publication
Journal: Psychopharmacology
December/20/1989
Abstract
Clozapine has had a uniquely favorable motor system side effect profile since its initial evaluations. This has been convincingly corroborated by many double blind, single blind, and open studies treating acute and chronic psychosis. The acute extrapyramidal syndromes of dystonia, akathisia and parkinsonism infrequently occur, whereas these syndromes develop in up to 75% of patients receiving traditional neuroleptics. Tardive dyskinesia can be suppressed with higher doses of clozapine given over extended periods. However, an antipsychotic effect can be achieved in many patients at doses below the dyskinesia suppressing level. There is no established causative relationship between clozapine and tardive dyskinesia, but there is a theoretical basis that this may occur. Preliminary data suggest clozapine has mild antiparkinsonian effects as well as efficacy in controlling dopamine agonist-induced psychosis without aggravating parkinsonism. A much wider use of clozapine will further characterize the magnitude of differences compared to other neuroleptics, and identify additional indications for this special compound.
Authors
Publication
Journal: Cancer Research
December/3/2006
Abstract
It is well established that high cyclooxygenase-2 (COX-2) expression contributes to the aggressive behavior of breast and other malignancies. Due to concerns regarding the safety of long-term use of COX-2 inhibitors as well as a desire to seek more effective alternatives to prevent and treat metastatic disease, we tested the hypothesis that inhibition of downstream signaling by the COX-2 product prostaglandin E(2) (PGE(2)) would be as effective as inhibiting global prostaglandin synthesis. PGE(2) acts through four G-protein-coupled receptors designated EPEP) receptors on cancer behavior and we discuss our own recent findings that antagonists of the PGE receptor subtype 4, EPEP receptors should be investigated as an approach to exploit the high COX-2 activity in many epithelial malignancies.
Publication
Journal: Journal of general microbiology
November/19/1987
Abstract
Candida albicans produces extracellular polymeric material (EP) which contains a mannoprotein adhesin. EP isolated from culture supernatants of C. albicans GDH 2346 consisted of a mixture of glycoprotein components and inhibited yeast adhesion to buccal epithelial cells by up to 60%. Partial purification of the adhesin was achieved by a two-step procedure involving chromatography of EP on concanavalin A-Sepharose and DEAE-cellulose. The purified adhesin inhibited adhesion to buccal cells 30 times more efficiently (on a weight basis) than unfractionated EP. Pretreatment of EP with heat, dithiothreitol or proteolytic enzymes either partially or completely destroyed its ability to inhibit adhesion, whereas pretreatment with sodium periodate or alpha-mannosidase had little or no effect. These results suggest that the protein portion of the mannoprotein adhesin is more important than the carbohydrate moiety in mediating yeast attachment to buccal epithelial cells.
Publication
Journal: Applied Microbiology and Biotechnology
November/12/1995
Abstract
The enzymatic activity of activated sludge was investigated with special emphasis on the localization of the enzymes in the sludge floc matrix. Activated sludge from an advanced activated-sludge treatment plant, performing biological N and P removal, was used. An enzymatic fingerprint was established using a panel of six different enzymes. The fingerprint revealed peptidase as the most dominating specific enzyme tested. By monitoring sludge bulk enzymatic activity over a 3-month period using fluorescein diacetate as an enzyme substrate, considerable variations in activity were observed even over short periods (a few days). The variation in esterase activity was to some extent correlated to the presence of humic compounds in the sludge, but not to the sludge protein content. Comparison of full sludge enzyme activity to the activity of a batch-grown sludge culture indicated that enzymes accumulated in sludge flocs. A large proportion of the exoenzymes were immobilized in the sludge by adsorption in the extracellular polymeric substances (EPS) matrix. This was demonstrated by extraction of EPS from the activated sludge using cation exchange. Contemporary to the release of EPS a very large fraction of the exoenzymes was released into the water. This showed that the exoenzymes should be considered to be an integrated part of the EPS matrix rather than as direct indicators of the microbial activity or biomass.
Publication
Journal: EMBO Journal
August/18/1999
Abstract
In eukaryotes, tyrosine protein phosphorylation has been studied extensively, while in bacteria, it is considered rare and is poorly defined. We demonstrate that Escherichia coli possesses a gene, etk, encoding an inner membrane protein that catalyses tyrosine autophosphorylation and phosphorylation of a synthetic co-polymer poly(Glu:Tyr). This protein tyrosine kinase (PTK) was termed Ep85 or Etk. All the E.coli strains examined possessed etk; however, only a subset of pathogenic strains expressed it. Etk is homologous to several bacterial proteins including the Ptk protein of Acinetobacter johnsonii, which is the only other known prokaryotic PTK. Other Etk homologues are AmsA of the plant pathogen Erwinia amylovora and Orf6 of the human pathogen Klebsiella pneumoniae. These proteins are involved in the production of exopolysaccharide (EPS) required for virulence. We demonstrated that like Etk, AmsA and probably also Orf6 are PTKs. Taken together, these findings suggest that tyrosine protein phosphorylation in prokaryotes is more common than was appreciated previously, and that Etk and its homologues define a distinct protein family of prokaryotic membrane-associated PTKs involved in EPS production and virulence. These prokaryotic PTKs may serve as a new target for the development of new antibiotics.
Publication
Journal: PLoS ONE
December/4/2011
Abstract
Trypanosoma brucei and related pathogens transcribe most genes as polycistronic arrays that are subsequently processed into monocistronic mRNAs. Expression is frequently regulated post-transcriptionally by cis-acting elements in the untranslated regions (UTRs). GPEET and EP procyclins are the major surface proteins of procyclic (insect midgut) forms of T. brucei. Three regulatory elements common to the 3' UTRs of both mRNAs regulate mRNA turnover and translation. The glycerol-responsive element (GRE) is unique to the GPEET 3' UTR and regulates its expression independently from EP. A synthetic RNA encompassing the GRE showed robust sequence-specific interactions with cytoplasmic proteins in electromobility shift assays. This, combined with column chromatography, led to the identification of 3 Alba-domain proteins. RNAi against Alba3 caused a growth phenotype and reduced the levels of Alba1 and Alba2 proteins, indicative of interactions between family members. Tandem-affinity purification and co-immunoprecipitation verified these interactions and also identified Alba4 in sub-stoichiometric amounts. Alba proteins are cytoplasmic and are recruited to starvation granules together with poly(A) RNA. Concomitant depletion of all four Alba proteins by RNAi specifically reduced translation of a reporter transcript flanked by the GPEET 3' UTR. Pulldown of tagged Alba proteins confirmed interactions with poly(A) binding proteins, ribosomal protein P0 and, in the case of Alba3, the cap-binding protein eIF4E4. In addition, Alba2 and Alba3 partially cosediment with polyribosomes in sucrose gradients. Alba-domain proteins seem to have exhibited great functional plasticity in the course of evolution. First identified as DNA-binding proteins in Archaea, then in association with nuclear RNase MRP/P in yeast and mammalian cells, they were recently described as components of a translationally silent complex containing stage-regulated mRNAs in Plasmodium. Our results are also consistent with stage-specific regulation of translation in trypanosomes, but most likely in the context of initiation.
Publication
Journal: Canadian Journal of Physiology and Pharmacology
September/28/2006
Abstract
Prostaglandins (PGs), platelet-activating factor (PAF), and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific pro-inflammatory genes. The mechanism of action of these lipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G-protein-coupled receptors (GPCR). Increasing evidence suggests the existence of a functional intracellular GPCR population. It has been proposed that immediate effects are mediated via cell surface receptors whereas long-term responses are dependent upon intracellular receptor effects. Indeed, receptors for PAF, LPA, and PGE(2) (specifically EP(1), EP(3), and EP(4)) localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pigs, rat hepatocytes, and cells overexpressing each receptor. Stimulation of isolated nuclei with these lipids reveals biological functions including transcriptional regulation of major genes, namely c-fos, cylooxygenase-2, and endothelial as well as inducible nitric oxide synthase. In the present review, we shall focus on the nuclear localization and signaling of GPCRs recognizing PGE(2), PAF, and LPA phospholipids as ligands. Mechanisms on how nuclear PGE2, PAF, and LPA receptors activate gene transcription and nuclear localization pathways are presented. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; accordingly, intracellular GPCRs constitute a distinctive mode of action for gene regulation.
Publication
Journal: European Journal of Neuroscience
January/16/2006
Abstract
Alzheimer's disease (AD) is associated with gliosis, neuroinflammation and higher levels of prostaglandins. Conflicting roles for cyclooxygenases and prostaglandins in the etiopathology of AD have been reported. We hypothesized that PGE2 signaling through <em>EP</em>2 and <em>EP</em>4 G-protein-coupled receptors could protect against amyloid beta-peptide (Abeta) neurotoxicity by increasing the cAMP signaling cascade. Using primary neuronal cultures, we investigated the presence of <em>EP</em> receptors (<em>EP</em>1-4) and the action of PGE2 and <em>EP</em> receptor agonists on neuronal susceptibility to Abeta1-42 toxicity. Low concentrations (1 microm) of PGE2, butaprost (<em>EP</em>2 agonist), and 1-hydroxy-PGE1 (<em>EP</em>4/<em>EP</em>3 agonist) were neuroprotective against Abeta1-42 toxicity, while sulprostone (<em>EP</em>3/<em>EP</em>1 agonist) at similar doses had no detectable effects. <em>EP</em>2 and <em>EP</em>4 receptor-mediated neuroprotection would involve changes in cAMP levels, as both <em>EP</em>2 and <em>EP</em>4 agonists increased intracellular cAMP concentration by approximately doubling basal levels, and both exhibited neuroprotective actions against Abeta-induced toxicity. The protein kinase A (PKA) inhibitor RpcAMPS significantly attenuated the neuroprotection by butaprost, but not that by 1-hydroxy-PGE1, implying differences between <em>EP</em>2 and <em>EP</em>4 receptor protective mechanisms. Additionally, the increase in reactive oxygen species generated following exposure to Abeta was reduced by stimulation of both <em>EP</em>2 and <em>EP</em>4 receptors. Together, these results indicate that PGE2 can protect neurons against Abeta toxicity by acting on given receptors and stimulating a cascade of intracellular events, including the cAMP-PKA pathway. We propose that development and testing of specific PGE2 receptor agonists downstream of cyclooxygenase could lead to therapeutic applications.
Publication
Journal: Fertility and Sterility
July/14/1996
Abstract
OBJECTIVE
To review current knowledge on the risk of ectopic pregnancy (EP), with the exception of contraceptive methods.
METHODS
Meta-analysis.
METHODS
Case control and cohort studies published between 1978 and 1994 in English, French, German, or Dutch, retrieved by Medline search, crossover search from the papers obtained, and hand-search on recent medical journals.
METHODS
A total number of 6,718 cases of EP in 27 case control studies and 13,049 exposed women in 9 cohort studies.
METHODS
Detected studies were tested for homogeneity. If homogeneity was not rejected, Mantel-Haenszel common odds ratios (OR) and 95% confidence intervals were calculated.
RESULTS
Previous EP, previous tubal surgery, documented tubal pathology, and in utero diethylstilbestrol (DES) exposure were found to be associated strongly with the occurrence of EP. Previous genital infections (pelvic inflammatory disease [PID], chlamydia, gonorrhoea), infertility, and a lifetime number of sexual partners>> 1 were associated with a mildly increased risk. For gonorrhoea, PID, previous EP, previous tubal surgery, and smoking, a higher common OR was calculated when using pregnant controls compared with using nonpregnant controls.
CONCLUSIONS
The strong risk in women with a previous EP, previous tubal surgery, documented tubal pathology, or in utero DES exposure justifies the exploration of a screening policy for EP among these women. If a risk factor reduces fertility chances, the OR detected when using pregnant controls is higher than the OR calculated using nonpregnant controls.
Publication
Journal: Clinical Chemistry
January/11/2010
Abstract
BACKGROUND
Hemoglobin A(1c) (Hb A(1c)) point-of-care (POC) instruments are widely used to provide rapid-turnaround results in diabetic care centers. We investigated the conformance of various Hb A(1c) POC instruments (In2it from Bio-Rad, DCA Vantage from Siemens, Afinion and Nycocard from Axis-Shield, Clover from Infopia, InnovaStar from DiaSys, A1CNow from Bayer, and Quo-Test from Quotient Diagnostics) with generally accepted performance criteria for Hb A(1c).
METHODS
The CLSI protocols EP-10, EP-5, and EP-9 were applied to investigate imprecision, accuracy, and bias. We assessed bias using 3 certified secondary reference measurement procedures and the mean of the 3 reference methods. Assay conformance with the National Glycohemoglobin Standardization Program (NGSP) certification criteria, as calculated from analyses with 2 different reagent lot numbers for each Hb A(1c) method, was also evaluated.
RESULTS
Because of disappointing EP-10 results, 2 of the 8 manufacturers decided not to continue the evaluation. The total CVs from EP-5 evaluations for the different instruments with a low and high Hb A(1c) value were: In2it 4.9% and 3.3%, DCA Vantage 1.8% and 3.7%, Clover 4.0% and 3.5%, InnovaStar 3.2% and 3.9%, Nycocard 4.8% and 5.2%, and Afinion 2.4% and 1.8%. Only the Afinion and the DCA Vantage passed the NGSP criteria with 2 different reagent lot numbers.
CONCLUSIONS
Only the Afinion and the DCA Vantage met the acceptance criteria of having a total CV <3% in the clinically relevant range. The EP-9 results and the calculations of the NGSP certification showed significant differences in analytical performance between different reagent lot numbers for all Hb A(1c) POC instruments.
Publication
Journal: British Journal of Pharmacology
November/14/2011
Abstract
OBJECTIVE
Cerebral aneurysm is a frequent cerebrovascular event and a major cause of fatal subarachnoid haemorrhage, but there is no medical treatment for this condition. Haemodynamic stress and, recently, chronic inflammation have been proposed as major causes of cerebral aneurysm. Nevertheless, links between haemodynamic stress and chronic inflammation remain ill-defined, and to clarify such links, we evaluated the effects of prostaglandin E(2) (PGE(2) ), a mediator of inflammation, on the formation of cerebral aneurysms.
METHODS
Expression of COX and prostaglandin E synthase (PGES) and PGE receptors were examined in human and rodent cerebral aneurysm. The incidence, size and inflammation of cerebral aneurysms were evaluated in rats treated with COX-2 inhibitors and mice lacking each prostaglandin receptor. Effects of shear stress and PGE receptor signalling on expression of pro-inflammatory molecules were studied in primary cultures of human endothelial cells (ECs).
RESULTS
COX-2, microsomal PGES-1 and prostaglandin E receptor 2 (EP(2) ) were induced in ECs in the walls of cerebral aneurysms. Shear stress applied to primary ECs induced COX-2 and EP(2) . Inhibition or loss of COX-2 or EP(2) in vivo attenuated each other's expression, suppressed nuclear factor κB (NF-κB)-mediated chronic inflammation and reduced incidence of cerebral aneurysm. EP(2) stimulation in primary ECs induced NF-κB activation and expression of the chemokine (C-C motif) ligand 2, essential for cerebral aneurysm.
CONCLUSIONS
These results suggest that shear stress activated PGE(2) -EP(2) pathway in ECs and amplified chronic inflammation via NF-κB. We propose EP(2) as a therapeutic target in cerebral aneurysm.
Publication
Journal: Nature
April/28/1985
Abstract
In vitro stimulation of mononuclear cells from human peripheral blood with mitogens causes the release of factors (monokines and lymphokines) which possess distinct biological activities. One such factor, termed 22K, can induce production of human beta-interferon (HuIFN-beta) in cultured human fibroblasts, thereby rendering these cells resistant to virus infection. Here we report the complete purification and partial sequencing (39 N-terminal amino acids) of this factor, whose relative molecular mass was estimated by SDS-polyacrylamide gel electrophoresis to be 17,000 (17K). In addition to an antiviral effect, the pure protein exhibits several other biological activities. Most significantly, intravenous (i.v.) injection of the factor in rabbits caused fever and granulopenia at doses of 0.1-1 microgram per kg, effects which we attribute to a monokine called endogenous pyrogen (EP). In vitro, the protein was scored as positive in a LAF (lymphocyte-activating factor) assay at 0.1-1 ng ml-1. LAF and EP are considered to be members of one family of monokines, called interleukin-1 (IL-1). For this reason, and also because the amino-acid sequence of the 22K factor is at least partially homologous to a complementary DNA-derived IL-1 sequence, we postulate that the 22K factor also belongs to the IL-1 family.
Publication
Journal: Journal of Biological Chemistry
June/13/2001
Abstract
Although a number of prostaglandin E(2) (PGE(2)) receptor subtypes have been cloned, limited studies have been performed to elucidate subtypes that subserve specific actions of this eicosanoid, in part because of a paucity of selective receptor antagonists. Using reverse transcription-polymerase chain reaction (PCR) and antisense oligonucleotides, we examined which prostaglandin E(2) receptor (<em>EP</em> receptor) subtypes are expressed in sensory neurons and which mediate the PGE(2)-induced increase in cAMP production and augmentation of peptide release. Reverse transcription-PCR of cDNA isolated from rat sensory neurons grown in culture revealed PCR products for the <em>EP</em>1, <em>EP</em>2, <em>EP</em>3C, and <em>EP</em>4 receptor subtypes but not the <em>EP</em>3A or <em>EP</em>3B. Preexposing neuronal cultures for 48 h to antisense oligonucleotides of <em>EP</em>3C and <em>EP</em>4 mRNA diminished expression of the respective receptors by approximately 80%, abolished the PGE(2)-stimulated production of cAMP, and blocked the ability of PGE(2) to augment release of immunoreactive substance P and calcitonin gene-related peptide. Pretreating with individual antisense against the <em>EP</em>2, <em>EP</em>3C, or <em>EP</em>4 receptors or combinations of missense oligonucleotides had no effect on PGE(2)-induced activity. Treatment with antisense to <em>EP</em>3C and <em>EP</em>4 receptor subtypes did not alter the ability of forskolin to increase cAMP or enhance peptide release. These results demonstrate that sensory neurons are capable of expressing multiple <em>EP</em> receptor subtypes but that only the <em>EP</em>3C and <em>EP</em>4 receptors mediate PGE(2)-induced sensitization of sensory neurons.
Publication
Journal: Cancer
November/19/1989
Abstract
Adenomas that contain early invasive carcinoma (ACIC) represent the earliest form of clinically relevant cancer of the colorectum in most patients. In order to assess the incidence of nodal metastases of ACIC, we studied 31 patients in whom the colon was resected after endoscopic polypectomy (EP) done from 1975 to 1987. We also reviewed the pathologic features reported in individual cases and in literature series of ACIC with lymph node metastases published from 1958 to 1986. The lymph node metastatic potential of ACIC is relatively high, ranging from an average value of 8.5% in the literature of to 16.1% in our own study, and is equivalent to the range of 10%-17% that occurs in colorectal carcinomas that invade the submucosa. When an ACIC is seen in an EP specimen in which the polypectomy margin is normal, the decision as to whether the patient should enter a follow-up protocol or have radical surgical resection is determined by the assessment of the probability of the occurrence of nodal metastases. According to several authors, certain histopathologic features make it possible to distinguish between an ACIC with a high-risk of nodal metastases versus those with a low-risk. The most relevant pathologic parameters include the state of the resection margins, the grade of the invasive carcinoma, and the presence or absence of vascular invasion. Of 351 cases of ACIC that were operated on, derived from 16 literature series, 45.6% were high-risk cases and 8.5% had lymph node metastases. In our group of high-risk ACIC that had surgical resection subsequently, the lymph node metastatic rate was 35.7%. Our results help to estimate the nodal metastatic potential of early colorectal carcinomas and stress the importance of adequate pathologic evaluation in order to assess metastatic risk in these patients accurately.
Publication
Journal: Current Biology
September/29/2008
Abstract
Bacterial pathogens and symbionts must suppress or negate host innate immunity. However, pathogens release conserved oligomeric and polymeric molecules or MAMPs (Microbial Associated Molecular Patterns), which elicit host defenses [1], [2] and [3]. Extracellular polysaccharides (EPSs) are key virulence factors in plant and animal pathogenesis, but their precise function in establishing basic compatibility remains unclear [4], [5], [6] and [7]. Here, we show that EPSs suppress MAMP-induced signaling in plants through their polyanionic nature [4] and consequent ability to chelate divalent calcium ions [8]. In plants, Ca2+ ion influx to the cytosol from the apoplast (where bacteria multiply [4], [5] and [9]) is a prerequisite for activation of myriad defenses by MAMPs [10]. We show that EPSs from diverse plant and animal pathogens and symbionts bind calcium. EPS-defective mutants or pure MAMPs, such as the flagellin peptide flg22, elicit calcium influx, expression of host defense genes, and downstream resistance. Furthermore, EPSs, produced by wild-type strains or purified, suppress induced responses but do not block flg22-receptor binding in Arabidopsis cells. EPS production was confirmed in planta, and the amounts in bacterial biofilms greatly exceed those required for binding of apoplastic calcium. These data reveal a novel, fundamental role for bacterial EPS in disease establishment, encouraging novel control strategies.
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