| 1. |
- Adner, Mikael, et al.
(author)
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Budesonide Prevents Cytokine-Induced Decrease of the Relaxant Responses to Formoterol and Terbutaline, but Not to Salmeterol, in Mouse Trachea
- 2010
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 333:1, s. 273-280
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Journal article (peer-reviewed)abstract
- During asthma exacerbations, increased airway inflammation may impair the effects of beta(2)-adrenoceptor (beta(2)AR) agonists. It is unclear whether this impairment is prevented by inhaled glucocorticoids (GCs). We have investigated the relaxation of carbachol-contracted mouse tracheal segments to the beta(2)AR agonists formoterol, terbutaline, and salmeterol. The segments were pre-exposed for 4 days to the proinflammatory cytokines tumor necrosis factor alpha (100 ng/ml) and interleukin-1 beta (10 ng/ml) with or without the GC, budesonide (1 mu M). Formoterol and terbutaline induced greater maximal relaxation (R-max)than salmeterol. The cytokines decreased R-max of all beta(2)AR agonists, whereas budesonide had no effect. However, after concomitant treatment with cytokines and budesonide, the R-max values of formoterol and terbutaline were not impaired, whereas budesonide did not prevent the decrease in the R-max of salmeterol. A similar pattern was observed for cAMP production by the agonists. In tracheal smooth muscle, beta(2)AR mRNA was not affected by the cytokines but increased with budesonide. However, the cytokines markedly increased cyclooxygenase (COX)-2 mRNA expression, which may lead to heterologous desensitization of beta(2)AR. It is noteworthy that the cytokine-induced increase of COX-2 was blocked by concomitant budesonide suggesting that heterologous desensitization of beta(2)AR by the cytokines may be prevented by budesonide treatment. Budesonide prevented cytokine-induced impairment of the tracheal relaxation and beta(2)AR/cAMP signaling for formoterol but not for salmeterol. This suggests that differences exist between formoterol and salmeterol in beta(2)AR coupling/activation and/or signal transduction upstream of cAMP. These results imply that maximal bronchodilator effects of formoterol, but not of salmeterol, are maintained by budesonide treatment during periods with increased inflammation, such as asthma exacerbations.
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| 2. |
- Ammoun, Sylwia, et al.
(author)
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Distinct Recognition of OX1 and OX2 Receptors by Orexin Peptides
- 2003
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 305:2, s. 507-514
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Journal article (peer-reviewed)abstract
- In this study, we have compared the abilities of orexin-A and orexin-B and variants of orexin-A to activate different Ca(2+) responses (influx and release) in human OX(1) and OX(2) receptor- expressing Chinese hamster ovary cells. Responses mediated by activation of both receptor subtypes with either orexin-A or -B were primarily dependent on extracellular Ca(2+), suggesting similar activation of Ca(2+) influx as we have previously shown for orexin-A and OX(1) receptors. Amino acid-wise truncation of orexin-A reduced its ability to activate OX(1) and OX(2) receptors, but the response mediated by the OX(2) receptor was more resistant to truncation than the response mediated by the OX(1) receptor. We also performed a sequential replacement of amino acids 14 to 26 with alanine in the truncated orexin-A variant orexin-A(14-33). Replacement of the same amino acids produced a fall in the potency for each receptor subtype, but the reduction was less prominent for the OX(2) receptor. The most marked reduction was produced by the replacement of Leu20, Asp25, and His26 with alanine. Interestingly, extracellular Ca(2+) dependence of responses to some of the mutated peptides was different from those of orexin-A and -B. The mutagenesis also suggests that although the determinants required from orexin-A for binding to and activation of the receptor are highly conserved between the orexin receptor subtypes, the OX(2) receptor requires fewer determinants. This might in part explain why orexin-B has the affinity and potency equal to orexin-A for this subtype, although it has 10- to 100-fold lower affinity and potency for the OX(1) receptor.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Boger, Elin, et al.
(author)
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A Novel In Vivo Receptor Occupancy Methodology for the Glucocorticoid Receptor : Toward An Improved Understanding of Lung Pharmacokinetic/Pharmacodynamic Relationships
- 2015
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 353:2, s. 279-287
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Journal article (peer-reviewed)abstract
- Investigation of pharmacokinetic/pharmacodynamic (PK/PD) relationships for inhaled drugs is challenging because of the limited possibilities of measuring tissue exposure and target engagement in the lung. The aim of this study was to develop a methodology for measuring receptor occupancy in vivo in the rat for the glucocorticoid receptor (GR) to allow more informative inhalation PK/PD studies. From AstraZeneca's chemical library of GR binders, compound 1 [N-(2-amino-2-oxo-ethyl)-3-[5-[(1R,2S)-2-(2,2-difluoropropanoylamino)-1-(2,3-dihydro-1,4-benzodioxin-6-yl) propoxy] indazol-1-yl]-N-methyl-benzamide] was identified to have properties that are useful as a tracer for GR in vitro. When given at an appropriate dose (30 nmol/kg) to rats, compound 1 functioned as a tracer in the lung and spleen in vivo using liquid chromatography-tandem mass spectrometry bioanalysis. The methodology was successfully used to show the dose-receptor occupancy relationship measured at 1.5 hours after intravenous administration of fluticasone propionate (20, 150, and 750 nmol/kg) as well as to characterize the time profile for receptor occupancy after a dose of 90 nmol/kg i.v. The dose giving 50% occupancy was estimated as 47 nmol/kg. The methodology is novel in terms of measuring occupancy strictly in vivo and by using an unlabeled tracer. This feature confers key advantages, including occupancy estimation not being influenced by drug particle dissolution or binding/dissociation taking place postmortem. In addition, the tracer may be labeled for use in positron emission tomography imaging, thus enabling occupancy estimation in humans as a translatable biomarker of target engagement.
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| 8. |
- Casselbrant, Anna, 1970, et al.
(author)
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Luminal Polyethylene Glycol Alleviates Intestinal Preservation Injury Irrespective of Molecular Size
- 2018
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 366:1, s. 29-36
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Journal article (peer-reviewed)abstract
- Intestinal preservation injury (IPI) and the resulting mucosa injury raise several serious challenges early after intestinal transplantation. The current clinical approach using only vascular perfusion allows the shortest preservation period among the abdominal organs. The experimental addition of luminal polyethylene glycol (PEG) solutions has been repeatedly suggested to alleviate preservation injury, improve graft quality, and prolong the preservation time. We investigated whether the molecular mass of PEG in solution influences the development of intestinal preservation injury. Small intestines of Sprague-Dawley rats were perfused with University of Wisconsin solution. Group 1 underwent vascular perfusion only (clinical control), group 2 received additional luminal PEG3350 Da, group 3 received luminal PEG10000 Da, and group 4 received luminal PEG20000 Da (n = 8/group). Tissue samples were obtained after 4, 8, and 14 hours. We studied the tissue damage (Chiu/Park score, Goblet cells, apoptosis, tight junctions), activation of c-Jun NH2-terminal kinase (JNK), and p38-mitogen-activated protein kinase (MAPK), and we performed Ussing chamber assessments. Mucosal morphologic and electrophysiologic parameters were significantly improved in the groups receiving luminal PEG. There was significantly less apoptotic activity in groups 2, 3, and 4. Both MAPKs revealed an activation peak after 4 hours with group 3 showing lesser p38-MAPK activation. PEG 20 kDa interfered with protein immunodetection. The results indicate that luminal solutions of PEG of medium and large molecular mass significantly delay the onset and development of IPI, providing further evidence that luminal interventions may allow for longer cold storage intervals of intestinal grafts.
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| 9. |
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| 10. |
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| 11. |
- Chan, K. Y., et al.
(author)
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Characterization of the Calcitonin Gene-Related Peptide Receptor Antagonist Telcagepant (MK-0974) in Human Isolated Coronary Arteries
- 2010
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 334:3, s. 746-752
-
Journal article (peer-reviewed)abstract
- The sensory neuropeptide calcitonin gene-related peptide (CGRP) plays a role in primary headaches, and CGRP receptor antagonists are effective in migraine treatment. CGRP is a potent vasodilator, raising the possibility that antagonism of its receptor could have cardiovascular effects. We therefore investigated the effects of the antimigraine CGRP receptor antagonist telcagepant (MK-0974) [N-[(3R,6S)-6-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)azepan- 3-yl]-4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridine-1-yl)piperidine-1-c arboxamide] on human isolated coronary arteries. Arteries with different internal diameters were studied to assess the potential for differential effects across the coronary vascular bed. The concentration-dependent relaxation responses to human alpha CGRP were greater in distal coronary arteries (i.d. 600-1000 mu m; E-max = 83 +/- 7%) than proximal coronary arteries (i.d. 2-3 mm; E-max = 23 +/- 9%), coronary arteries from explanted hearts (i.d. 3-5 mm; E-max = 11 +/- 3%), and coronary arterioles (i.d. 200-300 mu m; E-max = 15 +/- 7%). Telcagepant alone did not induce contraction or relaxation of these coronary blood vessels. Pretreatment with telcagepant (10 nM to 1 mu M) antagonized alpha CGRP-induced relaxation competitively in distal coronary arteries (pA(2) = 8.43 +/- 0.24) and proximal coronary arteries and coronary arterioles (1 mu M telcagepant, giving pK(B) = 7.89 +/- 0.13 and 7.78 +/- 0.16, respectively). alpha CGRP significantly increased cAMP levels in distal, but not proximal, coronary arteries, and this was abolished by pretreatment with telcagepant. Immunohistochemistry revealed the expression and colocalization of the CGRP receptor elements calcitonin-like receptor and receptor activity-modifying protein 1 in the smooth muscle cells in the media layer of human coronary arteries. These findings in vitro support the cardiovascular safety of CGRP receptor antagonists and suggest that telcagepant is unlikely to induce coronary side effects under normal cardiovascular conditions.
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| 12. |
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| 13. |
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| 14. |
- Desbiens, Louisane, et al.
(author)
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Experimental Autoimmune Encephalomyelitis Potentiates Mouse Mast Cell Protease 4-Dependent Pressor Responses to Centrally or Systemically Administered Big Endothelin-1
- 2019
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 370:3, s. 437-446
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Journal article (peer-reviewed)abstract
- Multiple sclerosis is a neurodegenerative disease affecting predominantly female patients between 20 and 45 years of age. We previously reported the significant contribution of mouse mast cell protease 4 (mMCP-4) in the synthesis of endothelin-1 (ET-1) in healthy mice and in a murine model of experimental autoimmune encephalomyelitis (EAE). In the current study, the cardiovascular effects of ET-1 and big endothelin-1 (big-ET-1) administered systemically or intrathecally were assessed in the early preclinical phase of EAE in telemetry instrumented/conscious mice. Chymase-specific enzymatic activity was also measured in the lung, brain, and mast cell extracts in vitro. Finally, the impact of EAE immunization was studied on the pulmonary and brain mRNA expression of different genes of the endothelin pathway, interleukin-33 (IL-33), and monitoring of immunoreactive tumor necrosis factor-α (TNF-α). Systemically or intrathecally administered big-ET-1 triggered increases in blood pressure in conscious mice. One week post-EAE, the pressor responses to big-ET-1 were potentiated in wild-type (WT) mice but not in mMCP-4 knockout (KO) mice. EAE triggered mMCP-4–specific activity in cerebral homogenates and peritoneal mast cells. Enhanced pulmonary, but not cerebral preproendothelin-1 and IL-33 mRNA were found in KO mice and further increased 1 week post-EAE immunization, but not in WT animals. Finally, TNF-α levels were also increased in serum from mMCP-4 KO mice, but not WT, 1 week post-EAE. Our study suggests that mMCP-4 activity is enhanced both centrally and systemically in a mouse model of EAE.
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| 15. |
- Ericson, Mia, 1970, et al.
(author)
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Nicotinic acetylcholine receptors in the anterior, but not posterior, ventral tegmental area mediate ethanol-induced elevation of accumbal dopamine levels.
- 2008
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In: The Journal of pharmacology and experimental therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 326:1, s. 76-82
-
Journal article (peer-reviewed)abstract
- Ethanol-induced elevations of accumbal dopamine levels have been linked to the reinforcing properties of the drug. However, it has not yet been demonstrated where the primary point of action of ethanol is in the mesolimbic dopamine system, and there appear to be conflicting findings depending on methodology (electrophysiology, microdialysis, or intracranial self-administration). We have suggested that ethanol acts in the nucleus accumbens (nAc), where it activates a neuronal loop involving ventral tegmental nicotinic acetylcholine receptors (nAChRs) to elevate dopamine levels in the nAc. Application of ethanol in the nAc results in elevated dopamine levels in the same brain region, whereas administration in the anterior ventral tegmental area (VTA) fails to influence dopamine output. In the present study, we were able to repeat these findings. In addition, application of ethanol in the posterior VTA also failed to influence nAc dopamine levels. Perfusion of the nAChR antagonist mecamylamine in the anterior VTA completely blocked the elevation of accumbal dopamine levels observed after ethanol perfusion in nAc, whereas mecamylamine in the posterior VTA had no effect. To detect a possible influence on phasic dopamine release, the dopamine transporter inhibitor nomifensine was included in the accumbal perfusate. In addition, under these conditions, ethanol in the anterior or posterior VTA failed to influence dopamine release in the nAc. These results support previous suggestions of distinct functions of the anterior and posterior VTA and give further evidence for our hypothesis of a nAc-anterior VTA-nAc neuronal circuitry involved in the dopamine-activating effects of ethanol.
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| 16. |
- Ericson, Mia, 1970, et al.
(author)
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The smoking cessation medication varenicline attenuates alcohol and nicotine interactions in the rat mesolimbic dopamine system.
- 2009
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In: The Journal of pharmacology and experimental therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 329:1, s. 225-30
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Journal article (peer-reviewed)abstract
- Varenicline was recently approved as an aid for smoking cessation. Patients treated with varenicline have reported a concomitant reduction in their alcohol consumption. This compound has also been demonstrated to reduce alcohol seeking and consumption in alcohol high-preferring rats. Based on the extensive coabuse of nicotine and alcohol, the aim of the present study was to explore whether interactions among varenicline, nicotine, and ethanol in the brain reward system could indicate the use of varenicline also for alcohol dependence. Using the in vivo microdialysis method, we investigated the effects of systemic injections of varenicline on the extracellular accumbal dopamine levels in response to a systemic challenge of ethanol, nicotine, or the combination of nicotine and ethanol in the experimental rat. Acute systemic coadministration of varenicline and ethanol counteracted each others' respective enhancing effect on dopamine levels in the nucleus accumbens. However, after 5 days of varenicline pretreatment, acute combined varenicline and ethanol administration raised dopamine levels to the same extent as either drug alone. Furthermore, after varenicline pretreatment an acute injection of varenicline antagonized the dopamine stimulatory effect of acute nicotine as well as that of systemic coadministration of ethanol and nicotine. In contrast, a pronounced additive dopamine increase was observed when nicotine and ethanol were coadministered in vehicle-pretreated rats. The antismoking agent varenicline exhibits properties with respect to its interaction with ethanol and nicotine in the brain reward system that may be beneficial for treating patients with alcohol dependence with (and possibly also without) concomitant nicotine dependence.
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| 17. |
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| 18. |
- Farooq, Shukkur Muhammed, et al.
(author)
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Therapeutic Effect of Blocking CXCR2 on Neutrophil Recruitment and Dextran Sodium Sulfate-Induced Colitis
- 2009
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 329:1, s. 123-129
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Journal article (peer-reviewed)abstract
- Dextran sodium sulfate (DSS)-induced colitis in mice is characterized by polymorphonuclear neutrophil (PMN) infiltration into the colonic mucosa and lumen. The mechanism by which this occurs is unclear. To begin to understand the mechanism, we determined the role of the PMN chemokine receptor, CXCR2, in DSS-induced colitis by using CXCR2(-/-) mice or by neutralizing CXCR2. DSS was administered through drinking water to CXCR2(-/-) and BALB/c mice for 5 days followed by regular water for 1 day. In the neutralization study, mice were injected with control serum or goat anti-CXCR2 antiserum. BALB/c mice receiving DSS and control serum-injected mice receiving DSS lost weight and showed considerable clinical illness. Histological observation revealed submucosal edema, PMN infiltration into the submucosa and mucosa, extensive crypt damage with abscesses, and ulceration. In contrast, both the CXCR2(-/-) and anti-CXCR2 antiserum-treated mice gained weight and had significantly lower symptom scores. Histology of these mice showed submucosal edema but relatively intact crypt architecture and very few ulcers. Significantly fewer PMNs were found in the mucosa in anti-CXCR2 antiserum compared with control serum-injected inflamed mice, but no significant difference in eosinophil infiltration was observed between the groups. Our experiments identify a role for CXCR2 in DSS-induced colitis and suggest that antagonizing CXCR2 provides some therapeutic efficacy, possibly by impeding PMN recruitment into the mucosa. Antagonizing CXCR2 may form the basis for therapeutic drugs directed at controlling colitis.
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| 19. |
- Giglio, Daniel, 1977, et al.
(author)
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Changes in the Neuronal Control of the Urinary Bladder in a Model of Radiation Cystitis.
- 2018
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In: The Journal of pharmacology and experimental therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0103 .- 0022-3565. ; 365:2, s. 327-335
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Journal article (peer-reviewed)abstract
- Currently, we have assessed the neuronal control of the urinary bladder in radiation cystitis and whether interstitial cells contribute to the condition. Fourteen days after bladder irradiation (20 Gy), rats were sedated and the urinary bladder was cut into two sagittal halves where electrical field stimulation (EFS; 5-20 Hz) was applied on the pelvic nerve afferents or stretch (80 mN) on one-half of the bladder, while contractions were registered on the contralateral half of the bladder in the absence and presence of increasing doses of imatinib (1-10 mg/kg; inhibitor of c-kit-positive interstitial cells), atropine (1 mg/kg; to block muscarinic M3receptors), or pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (2 mg/kg; P2X1purinoceptor antagonist). Urinary bladders were also excised for organ bath experiments, Western blot, quantitative polymerase chain reaction, and immunohistochemistry. In vivo, EFS contractions were enhanced after irradiation, and imatinib (1-10 mg/mg) inhibited contractions by EFS and stretched dose-dependently in controls but not in irradiated bladders. In the irradiated bladder in vitro, atropine resistance was increased and imatinib (100µM) inhibited contractions by EFS and agonists (ATP, methacholine) in irradiated bladders and controls. The urinary bladder expressions of P2X1purinoceptors, muscarinic M3receptor, choline acetyltransferase, c-kit, and the agonist of c-kit, stem cell factor, were not changed by irradiation. In conclusion, bladder irradiation affects several levels of neuronal control of the urinary bladder. Interstitial cells may contribute to some of the symptoms associated with radiation cystitis.
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| 20. |
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| 21. |
- Gullberg, Elisabet, et al.
(author)
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Identification of Cell Adhesion Molecules in the Human Follicle-Associated Epithelium That Improve Nanoparticle Uptake into the Peyer's Patches
- 2006
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 319:2, s. 632-639
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Journal article (peer-reviewed)abstract
- The aim of this study was to identify cell adhesion molecules that could serve as targets of the human follicle-associated epithelium (FAE) overlying Peyer's patches and to assess nanoparticle uptake levels across this epithelium. We first studied the expression of the mouse M-cell marker beta(1)-integrin and used a model of human FAE derived from intestinal epithelial Caco-2 cells and Raji B-cells to identify additional potential targets by cDNA array. The protein expression of potential targets in the model FAE and in human ileal FAE tissues was quantified by immunofluorescence. Integrin targeting was studied by investigating the transport of Arg-Gly-Asp (RGD)-coated (integrin- binding), Arg-Gly-Glu (RGE)-coated (nonintegrin-binding), and uncoated nanoparticles across ileal specimens mounted in Ussing chambers. Both beta(1)-integrin and the cell adhesion molecule CD9 were more abundantly expressed in the model and human FAE compared with the Caco-2 control cells or villus epithelium (VE). Uncoated nanoparticles were not taken up across either FAE or VE. General integrin targeting with RGD improved the nanoparticle transport dramatically across the FAE and to a lower extent across the VE. Compared with RGE, RGD improved transport 4-fold across the FAE. There was no difference in the transport of RGD- and RGE-coated nanoparticles across the VE. In conclusion, beta(1)-integrin and CD9 were identified as targets in human FAE. The difference in RGD- and RGE-mediated transport across the FAE, but not the VE, suggests that a specific integrin interaction was the dominating mechanism for improved nanoparticle uptake across the FAE., whereas charge interaction contributed substantially to the improved VE uptake.
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| 22. |
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| 23. |
- Hassan, Saadia Bashir, et al.
(author)
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Model for time dependency of the cytotoxic effect of CHS 828 in vitro suggests two different mechanisms of action
- 2001
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In: Journal of Pharmacology and Experimental Therapeutics. - 0022-3565 .- 1521-0103. ; 299:3, s. 1140-1147
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Journal article (peer-reviewed)abstract
- CHS 828 is a novel drug belonging to the cyanoguanidines. It has shown promising anticancer activity in many preclinical systems and is currently in early clinical trials. Our aim in this study was to assess the growth inhibitory effect of CHS 828 in comparison with paclitaxel, etoposide, and topotecan as a function of concentration and time. U937 GTB, RPMI 8226/S, MDA 231, primary cells from chronic lymphocytic leukemia, and normal mononuclear cells were exposed to CHS 828 and U937 GTB cells were exposed to paclitaxel, etoposide, and topotecan in 18 concentrations for times ranging from 1 to 72 h. Cell survival was measured after 72-h incubation by using the fluorometric microculture cytotoxicity assay. Nonlinear mixed effect modeling was used to model the concentration-effect curves with a modified Hill equation. Patterns of change of drug potency (IC(50)), slope of the concentration-effect curves, and plateau with time were studied. The log IC(50) for CHS 828 decreased with log time in a sigmoid manner for all cell types tested. Although very steep at short and long incubation, the concentration-effect curves became shallow at intermediate times. The log IC(50) for etoposide and topotecan was decreased with log time in a sigmoid manner. The log IC(50) for paclitaxel decreased linearly with log time. The information obtained from modeling the cytotoxic effect of CHS 828 and changes of IC(50) and slope parameters with exposure time suggests a heterogeneous cell response to CHS 828. This could indicate two distinct mechanisms of induction of cell death.
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| 24. |
- Henriquez-Hernandez, L. A., et al.
(author)
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Role of pituitary hormones on 17 alpha-ethinylestradiol-induced cholestasis in rat
- 2007
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 320:2, s. 695-705
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Journal article (peer-reviewed)abstract
- Estrogens cause intrahepatic cholestasis in susceptible women during pregnancy, after administration of oral contraceptives, or during postmenopausal hormone replacement therapy. 17 alpha-Ethinylestradiol ( EE) is a synthetic estrogen widely used to cause experimental cholestasis in rodents with the aim of examining molecular mechanisms involved in this disease. EE actions on the liver are thought to be mediated by estrogen receptor alpha ( ER alpha) and pituitary hormones. We tested this hypothesis by analyzing metabolic changes induced by EE in livers from hypophysectomized ( HYPOX) and hypothyroid rats. Microarray studies revealed that the number of genes regulated by EE was increased almost 4-fold in HYPOX rat livers compared with intact males. Little overlap was apparent between the effects of EE in intact and HYPOX rats, demonstrating that pituitary hormones play a critical role in the hepatic effects of EE. Consistently, hypophysectomy protects the liver against induction by EE of serum bilirubin and alkaline phosphatase, two markers of cholestasis and hepatotoxicity and modulates the effects of EE on several genes involved in bile acid homeostasis ( e. g., FXR, SHP, BSEP, and Cyp8b1). Finally, we demonstrate a novel mechanism of action of EE through binding and negative regulation of glucocorticoid receptor-mediated transcription. In summary, pituitary- and ER alpha- independent mechanisms contribute to development of EE-induced changes in liver transcriptome. Such mechanisms may be relevant when this model of EE-induced cholestasis is evaluated. The observation that the pharmacological effects of estrogen in liver differ in the absence or presence of the pituitary could be clinically relevant, because different drugs that block actions of pituitary hormones are now available.
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| 25. |
- Hjorth, Stephan, 1953, et al.
(author)
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(3S)-3-(2,3-difluorophenyl)-3-methoxypyrrolidine (IRL752)-a Novel Cortical-Preferring Catecholamine Transmission- and Cognition-Promoting Agent
- 2020
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In: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 374:3, s. 404-419
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Journal article (peer-reviewed)abstract
- Here we describe for the first time the distinctive pharmacological profile for (35)-3-(2,3-difluorophenyI)-3-nnethoxypyrrolidine (IRL752), a new phenyl-pyrrolidine derivative with regioselective central nervous system transmission-enhancing properties. IRL752 (3.7-150 mu mol/kg, s.c.) was characterized through extensive in vivo studies using behavioral, tissue neurochemical, and gene expression as well as microdialysis methods. Behaviorally, the compound normalized tetrabenazine-induced hypo-activity, whereas it was unable to stimulate basal locomotion in normal animals or either accentuate or reverse hyperactivity induced by amphetamine or MK-801. IRL752 induced but minor changes in monoaminergic tissue neurochemistry across noradrenaline (NA)- and dopamine (DA)-dominated brain regions. The expression of neuronal activity-, plasticity-, and cognition-related immediate early genes (IEGs), however, increased by 1.5-fold to 2-fold. Furthermore, IRL752 dose-dependently enhanced cortical catecholamine dialysate output to 600%-750% above baseline, whereas striatal DA remained unaltered, and NA rose to similar to 250%; cortical and hippocampal dialysate acetylcholine (ACh) increased to similar to 250% and 190% above corresponding baseline, respectively. In line with this cortically preferential transmission-promoting action, the drug was also procognitive in the novel object recognition and reversal learning tests. In vitro neurotarget affinity and functional data coupled to drug exposure support the hypothesis that 5-hydroxytryptannine 7 receptor and alpha 2(C)-adrenoceptor antagonism are key contributors to the in vivo efficacy and original profile of IRL752. The cortical-preferring facilitatory impact on cate-cholamine (and ACh) neurotransmission, along with effects on IEG expression and cognition-enhancing features, are in line with the potential clinical usefulness of IRL752 in conditions wherein these aspects may be dysregulated, such as in axial motor and cognitive deficits in Parkinson disease. SIGNIFICANCE STATEMENT This report describes the distinctive preclinical profile of (3S)3-(2,3-difluorophenyI)-3-nnethoxypyrrolidine (IRL752). Its in vivo neurochemical, behavioral, microdialysis, and gene expression properties are consistent with a cortically regioselective facilitatory impact on catecholaminergic and cholinergic neurotransmission accompanied by cognitive impairment-reversing features. The pharmacological characteristics of IRL752 are in line with the clinical usefulness of IRL752 in conditions wherein these aspects may be dysregulated, such as in axial motor and cognitive deficits in Parkinson disease.
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