| 1. |
- Austin, Paul F., et al.
(författare)
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The standardization of terminology of lower urinary tract function in children and adolescents : Update report from the standardization committee of the International Children's Continence Society
- 2016
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Ingår i: Neurourology and Urodynamics. - : Wiley. - 0733-2467 .- 1520-6777. ; 35:4, s. 471-481
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Tidskriftsartikel (refereegranskat)abstract
- AimThe impact of the original International Children's Continence Society (ICCS) terminology document on lower urinary tract (LUT) function resulted in the global establishment of uniformity and clarity in the characterization of LUT function and dysfunction in children across multiple healthcare disciplines. The present document serves as a stand-alone terminology update reflecting refinement and current advancement of knowledge on pediatric LUT function. MethodsA variety of worldwide experts from multiple disciplines within the ICCS leadership who care for children with LUT dysfunction were assembled as part of the standardization committee. A critical review of the previous ICCS terminology document and the current literature was performed. Additionally, contributions and feedback from the multidisciplinary ICCS membership were solicited. ResultsFollowing a review of the literature over the last 7 years, the ICCS experts assembled a new terminology document reflecting current understanding of bladder function and LUT dysfunction in children using the resources from the literature review, expert opinion and ICCS member feedback. ConclusionsThe present ICCS terminology document provides a current and consensus update to the evolving terminology and understanding of LUT function in children.
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| 2. |
- Austin, Paul F, et al.
(författare)
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The Standardization of Terminology of Lower Urinary Tract Function in Children and Adolescents : Update Report from the Standardization Committee of the International Children's Continence Society.
- 2014
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Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 0022-5347 .- 1527-3792. ; 191:6, s. 1863-1865
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The impact of the original International Children's Continence Society (ICCS) terminology document on lower urinary tract (LUT) function resulted in the global establishment of uniformity and clarity in the characterization of LUT function and dysfunction in children across multiple healthcare disciplines. The present document serves as a stand-alone terminology update reflecting refinement and current advancement of knowledge on pediatric LUT function.MATERIALS AND METHODS: A variety of worldwide experts from multiple disciplines within the ICCS leadership who care for children with LUT dysfunction were assembled as part of the standardization committee. A critical review of the previous ICCS terminology document and the current literature was performed. Additionally, contributions and feedback from the multidisciplinary ICCS membership were solicited.RESULTS: Following a review of the literature over the last 7 years, the ICCS experts assembled a new terminology document reflecting current understanding of bladder function and LUT dysfunction in children using the resources from the literature review, expert opinion and ICCS member feedback.CONCLUSIONS: The present ICCS terminology document provides a current and consensus update to the evolving terminology and understanding of LUT function in children.
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| 3. |
- Bauer, Stuart, et al.
(författare)
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Standardizing terminology in pediatric urology
- 2007
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Ingår i: Journal of Pediatric Urology. - : Elsevier BV. - 1477-5131 .- 1873-4898. ; 3:2, s. 163-163
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 4. |
- Chauvier, D, et al.
(författare)
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Targeting neonatal ischemic brain injury with a pentapeptide-based irreversible caspase inhibitor.
- 2011
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Ingår i: Cell death & disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Brain protection of the newborn remains a challenging priority and represents a totally unmet medical need. Pharmacological inhibition of caspases appears as a promising strategy for neuroprotection. In a translational perspective, we have developed a pentapeptide-based group II caspase inhibitor, TRP601/ORPHA133563, which reaches the brain, and inhibits caspases activation, mitochondrial release of cytochrome c, and apoptosis in vivo. Single administration of TRP601 protects newborn rodent brain against excitotoxicity, hypoxia-ischemia, and perinatal arterial stroke with a 6-h therapeutic time window, and has no adverse effects on physiological parameters. Safety pharmacology investigations, and toxicology studies in rodent and canine neonates, suggest that TRP601 is a lead compound for further drug development to treat ischemic brain damage in human newborns.
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| 5. |
- Chiale, P A, et al.
(författare)
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High prevalence of antibodies against beta 1- and beta 2-adrenoceptors in patients with primary electrical cardiac abnormalities.
- 1995
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097. ; 26:4, s. 864-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: This study sought to determine the prevalence of autoantibodies directed against the beta-adrenoceptors in patients with primary electrical cardiac abnormalities, including atrial arrhythmias, ventricular arrhythmias and conduction disturbances, in the absence of any other cardiac abnormality. BACKGROUND: Using synthetic peptides corresponding to the predicted sequences for the second extracellular loop of the human beta 1- and beta 2-adrenoceptors as antigenic targets, autoantibodies directed against the beta-adrenoceptors were recently shown to occur in patients with idiopathic dilated cardiomyopathy and Chagas' heart disease. METHODS: Eighty-six patients (57 with primary electrical abnormalities, 29 with idiopathic dilated cardiomyopathy) and 101 healthy and cardiopathic control subjects were studied. Antibodies against the beta 1- and beta 2-peptides were detected with an enzyme immunoassay performed in blinded manner. In nine selected (seropositive) cases, the immunoglobulin G (IgG) fraction was tested for functional effects on the rate of beating of cultured neonatal rat cardiomyocytes. RESULTS: Antibodies recognizing the beta 1- and beta 2-peptides were found in 11 (52.3%) of 21 patients with ventricular arrhythmias (p < 0.01), 5 (35.7%) of 14 patients with conduction disturbances (p < 0.05), 3 (13.6%) of 22 patients with atrial arrhythmias (p > 0.05) and 11 (37.9%) of 29 patients with dilated cardiomyopathy (p < 0.05) compared with 15 (14.8%) of 101 control subjects. A rapid increase in the rate of beating of the cultured cardiomyocytes was induced by IgG from a selected group of patients, suggesting an agonist-like interaction with a functional epitope. This response was mediated by stimulation of both the beta 1- and beta 2-adrenoceptors in the patients with primary ventricular arrhythmias but only the beta 1-adrenoceptors in the patients with idiopathic dilated cardiomyopathy. CONCLUSIONS: Primary ventricular arrhythmias and conduction disturbances, like idiopathic cardiomyopathy, show a high prevalence of antibodies interacting with functional epitopes of the beta-adrenoceptors, suggesting a common or similar abnormal immunoregulatory process.
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| 6. |
- Elies, Rozenn, et al.
(författare)
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Immunochemical and functional characterization of an agonist-like monoclonal antibody against the M2 acetylcholine receptor.
- 1998
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Ingår i: European journal of biochemistry / FEBS. - 0014-2956. ; 251:3, s. 659-66
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Tidskriftsartikel (refereegranskat)abstract
- Monoclonal antibodies were raised against a peptide corresponding to the second extracellular loop of the M2 acetylcholine receptor. One of the monoclonal antibodies, B8E5, was selected for further characterization on the basis of its high yield, its isotype (IgG2a), its dissociation kinetics and its agonist-like activity. The epitope recognized by B8E5 corresponded to the N-terminal part of the second extracellular loop of the receptor (V-R-T-V-E-) as determined by competition immunoassays and epitope scanning. The KA of B8E5 for the target peptide was assessed by surface plasmon resonance (SPR) to be 6.5x10(7) M(-1) by equilibrium and 3.7x10(7) M(-1) by kinetic analysis. B8E5 recognized the M2 acetylcholine receptor on rat cardiac tissue. It only recognized the non-reduced receptor in immunoblots. The antibody had no effect on antagonist binding but decreased the affinity for the agonist carbachol. B8E5 decreased the beating frequency of neonatal rat cardiomyocytes. The effect was specific since it was blocked by the target peptide and the antagonist atropine. The EC50 of the antibody corresponded to the KA measured by surface plasmon resonance. The physiological effect of the antibody did not lead to desensitization. The Fab fragments had no physiological effect; subsequent addition of anti-mouse IgG however restored the physiological effect. These results confirm that the N-terminus of the second extracellular loop is a functional target for antibodies against the M2 acetylcholine receptor. They suggest that the functional epitope is only accessible in the non-reduced receptor. The antibodies act through a functional dimerization of the receptor.
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| 7. |
- Eng, H, et al.
(författare)
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Beta 2-adrenergic receptor antibodies in myasthenia gravis.
- 1992
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Ingår i: Journal of autoimmunity. - 0896-8411. ; 5:2, s. 213-27
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Tidskriftsartikel (refereegranskat)abstract
- Although autoantibodies against the nicotinic acetylcholine receptor are the characteristic feature of the autoimmune disease myasthenia gravis (MG), no strong correlation is found between the autoantibody titer and the degree of clinical severity. Numerous studies have attempted to detect the presence of other autoantibody populations that might have a role in the pathology of the disease. We report, for the first time, that 18% of the MG patients we screened have antibodies in their serum to a peptide corresponding to the second extracellular loop of the human beta 2-adrenergic receptor (residues 172-197). Affinity purified antibodies to the beta 2-adrenergic receptor peptide 172-197 reacted with the human beta 2-adrenergic receptor protein obtained from transfected E. coli cell membrane extracts, but did not cross-react with the human AChR. Sufficient material was obtained from nine MG patients and it was found that the gamma globulin fraction from these patients immunoprecipitated the receptor, and that affinity purified IgG to peptide 172-197 competed for receptor binding with the beta-antagonist iodo-cyanopindolol. Using truncated peptides or amino acid modification procedures, no immunodominant B-cell epitope could be detected within region 172-197. Thus, a subpopulation of MG patients possesses anti-beta 2-adrenergic receptor antibodies which are a distinct set of autoantibodies with possible pharmacological activity.
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| 8. |
- Fu, Michael, 1963, et al.
(författare)
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Activity of receptors coupled to guanine nucleotide binding regulatory protein in doxorubicin induced cardiomyopathy.
- 1991
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Ingår i: Cardiovascular research. - 0008-6363. ; 25:2, s. 145-50
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVE--The aim was to study the activity of receptors coupled to guanine nucleotide binding regulatory proteins (G proteins) in doxorubicin induced cardiomyopathy, with special attention to G proteins, beta adrenoceptors, muscarinic receptors, and adenylyl cyclase. DESIGN--Messenger RNA of G proteins, densities and high affinity agonist binding of beta adrenoceptors and muscarinic receptors, activity of adenylyl cyclase, calcium influx, and in vivo lipid peroxidation were determined before, in the early stage, and in the later stage of doxorubicin cardiomyopathic heart failure. SUBJECTS--Sprague-Dawley rats between 150-200 g were used. Doxorubicin was given intravenously at two doses of 4 mg.kg-1 and 6 mg.kg-1 every third week (1st, 4th, 7th week) for nine weeks. Doxorubicin treated rats plus corresponding controls were killed at 3 weeks (n = 7), 6 weeks (n = 7), and 9 weeks (n = 6), respectively. MEASUREMENTS AND MAIN RESULTS--Northern blot and dot blot hybridisations of the total RNA revealed that messenger RNA of both stimulatory and inhibitory G proteins were identical between doxorubicin treated rats and controls. No alterations in the densities of beta adrenoceptors and muscarinic receptors were observed, neither did the high affinity agonist binding of beta adrenoceptors and muscarinic receptors change. Furthermore, modulation of adenylyl cyclase was unimpaired. In contrast, Ca(2+)-ATPase and serum water soluble fluorescent substance, a product of in vivo lipid peroxidation, were shown to increase dramatically in doxorubicin treated rats (4 mg.kg-1 for 6 and 9 weeks, 6 mg.kg-1 for 3, 6 and 9 weeks) as compared with corresponding controls. CONCLUSIONS--The findings suggest that, despite increased calcium influx and lipid peroxidation in doxorubicin induced cardiomyopathy, the activity of receptors coupled to G proteins remained normal.
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| 9. |
- Fu, Michael, 1963, et al.
(författare)
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Autoantibodies against cardiac G-protein-coupled receptors define different populations with cardiomyopathies but not with hypertension.
- 1994
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Ingår i: Clinical immunology and immunopathology. - 0090-1229. ; 72:1, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- It was previously shown that the second extracellular loop of cardiovascular G-protein-coupled receptors is an antigenic target for pharmacologically active autoantibodies in patients with idiopathic dilated cardiomyopathy. To extend these observations to cover patients with the same disease from different geographical origins or to patients with other cardiac diseases, peptides corresponding to the sequences of the second extracellular loops of the human M2 muscarinic receptors and beta adrenoceptors were used as antigens in an enzyme immunoassay. Sera from patients from Sweden and Japan with idiopathic dilated cardiomyopathy (DCM, n = 32), hypertrophic cardiomyopathy (HCM, n = 23), malignant essential hypertension (MEH, n = 11), malignant secondary hypertension (MSH, n = 10), and sera from healthy blood donors (HBD, n = 49) were tested. Sera from patients with DCM recognized the muscarinic receptor peptide in 38% of cases and the beta 1 adrenoceptor peptide in 31% of cases. In 50% of the positive patients, autoantibodies against both peptides coexisted as shown by competition experiments using both peptides as inhibitors. In HCM patients, there was a lower frequency of autoantibodies but with a higher but not significant predominance against the M2 peptide. No autoantibodies were detected in sera from patients with MEH or MSH. Autoantibodies against the M2 muscarinic receptors, affinity-purified from positive patients, displayed pharmacological activity as demonstrated by changes in the affinity and number of radioligand binding sites. In contrast, antibodies purified from positive HBD had no effect. These results confirm that autoantibodies displaying pharmacological activity against G-protein-coupled cardiovascular receptors are mainly restricted to patients with idiopathic dilated cardiomyopathy and that different autoantibody populations are responsible for the recognition of the different receptors.
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| 10. |
- Fu, Michael, 1963, et al.
(författare)
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Autoantibodies against the angiotensin receptor (AT1) in patients with hypertension.
- 2000
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Ingår i: Journal of hypertension. - 0263-6352. ; 18:7, s. 945-53
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Tidskriftsartikel (refereegranskat)abstract
- Sera from patients with malignant essential hypertension (n = 14), malignant secondary hypertension mainly attributable to renovascular diseases (n = 12) and renovascular diseases without malignant hypertension (n = 11) and from normotensive healthy blood donors (n = 35) were studied for the presence of autoantibodies against G-protein-coupled cardiovascular receptors. Autoantibodies against the angiotensin II receptor (AT1) were detected in 14, 33, 18 and 14% of patients with malignant essential hypertension, malignant secondary hypertension, renovascular diseases and control patients, respectively. Sensitivity of the enzyme immunoassay was assessed as 5 microg/ml IgG. Patients did not show antibodies against bradykinin (B2) or angiotensin II subtype 2 (AT2) receptors. Autoantibodies affinity-purified from positive patients localized AT receptors in Chinese hamster ovary transfected cells, and displayed a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These results demonstrate the existence of autoantibodies against a functional extracellular domain of human AT1 receptors in patients with malignant hypertension, and suggest that these autoantibodies might be involved in the pathogenesis of malignant hypertension.
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| 11. |
- Fu, Michael, 1963, et al.
(författare)
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Characterization of anti-peptide antibodies directed against an extracellular immunogenic epitope on the human alpha 1-adrenergic receptor.
- 1994
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Ingår i: Clinical and experimental immunology. - 0009-9104. ; 97:1, s. 146-51
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Tidskriftsartikel (refereegranskat)abstract
- A synthetic peptide corresponding to amino acids 192-218 of the second extracellular loop of the human alpha 1A-adrenergic receptor was used to raise antibodies in rabbits. Affinity-purified antibodies specifically recognized main bands with a molecular weight of about 68, 40 and 37 kD on the electrotransferred membrane proteins of rat ventricle membranes. The incubation of these antibodies with rat myocardial membranes resulted in a decrease in the number of binding sites for the specific radiolabelled alpha 1-antagonist prazosin. These antibodies were also able to mimic the effects of agonist stimulation as demonstrated by a positive chronotropic effect on cultured cardiomyocytes. These results constitute the first immunochemical evidence of the presence of both the A and B subtypes of the alpha 1-adrenergic receptor in the heart. They also confirm that the second extracellular loop of the alpha 1-adrenergic receptors is an immunologically and functionally important domain.
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| 12. |
- Fu, Michael, 1963, et al.
(författare)
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Decreased density of mesenteric arteries but not of myocardial endothelin receptors and function in rats with chronic ischemic heart failure.
- 1993
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Ingår i: Journal of cardiovascular pharmacology. - 0160-2446. ; 22:2, s. 177-82
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Tidskriftsartikel (refereegranskat)abstract
- Mesenteric artery and cardiac ventricular endothelin receptors and endothelin-1-induced pressor responses were studied in normal rats and rats with chronic congestive heart failure induced by myocardial ischemia (4 weeks after coronary artery ligation). In mesenteric arteries of rats with chronic ischemic heart failure, endothelin receptor density was significantly decreased by 59%, whereas the dissociation constant was increased 2.8-fold, as compared with controls. There were, however, no changes in endothelin-receptor density or the dissociation constant in cardiac ventricular membrane preparations from rats with congestive heart failure as compared with controls. In pithed rats with congestive heart failure there was a reduced pressor response to a bolus injection of endothelin-1 (800 pmole/kg body weight), while the vasodilatory response was unaltered as compared with sham-operated controls. These results demonstrate that there is a decreased vascular endothelin-receptor function due to a down-regulated endothelin receptor. The in vivo data indicate that this is due to impaired endothelin A but not endothelin B receptor function. Thus, there is an impaired arterial but not cardiac ventricular endothelin receptor-mediated signalling system in the rat with chronic ischemic heart failure.
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| 13. |
- Fu, Michael, 1963, et al.
(författare)
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Diabetes-induced changes in the Gi-modulated muscarinic receptor-adenylyl cyclase system in rat myocardium.
- 1994
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Ingår i: Pharmacology & toxicology. - 0901-9928. ; 75:3-4, s. 186-93
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Tidskriftsartikel (refereegranskat)abstract
- The inhibitory guanine nucleotide binding regulatory protein (Gi)-mediated muscarinic receptor-adenylyl cyclase system was studied in myocardium from adult male Wistar rats with 10 weeks of diabetes induced by a single intravenous injection of streptozotocin (60 mg/kg). Neither the messenger ribonucleic acid level nor the amount of Gi was changed in the streptozotocin diabetic group as compared to the control group. The activity of the adenylyl cyclase stimulated by guanyliminodiphosphate was decreased by 48% in the streptozotocin diabetic group whereas stimulated activities of adenylyl cyclase by sodium fluoride and forskolin remained unchanged. The inhibition of forskolin-stimulated adenylyl cyclase activity by carbachol was more potent in membranes from the streptozotocin diabetic group than that in membranes from the control group. The competition binding curve between (3H)- quinuclidinyl benzilate and carbachol obtained from the streptozotocin diabetic group was shifted to the left as compared to the control group. These results suggest that the myocardium of streptozotocin-induced diabetic rats exhibited an increase in Gi function as demonstrated by the increased inhibition of guanyliminodiphosphate-mediated adenylyl cyclase and the superhigh affinity for carbachol of the muscarinic receptors. As there were signs, similar to those seen in clinical heart failure, in the streptozotocin diabetic group, these results demonstrate that functional alteration of Gi might underlie, at least in part, the cardiac dysfunction that is associated with diabetes.
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| 14. |
- Fu, Michael, 1963, et al.
(författare)
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Effect of metoprolol on activity of beta-adrenoceptor coupled to guanine nucleotide binding regulatory proteins in adriamycin-induced cardiotoxicity.
- 1991
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Ingår i: Basic research in cardiology. - 0300-8428. ; 86:2, s. 117-26
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Tidskriftsartikel (refereegranskat)abstract
- Prevention of cardiotoxicity without interfering with the therapeutic efficacy of adriamycin is a very crucial question. We have investigated the activity of beta-adrenoceptor coupled to guanine nucleotide binding regulatory proteins (G-proteins) and Ca(2+)-ATPase activity in experimental adriamycin-induced cardiotoxicity and the influence of metoprolol treatment on these variables. Adriamycin was administered to rats intravenously as a single dose of 6 mg/kg, and metoprol was continuously given by means of implanted osmotic pumps. beta-Adrenoceptor characteristics were measured by radioligand-binding experiments and by basal and stimulated adenylyl cyclase activity. Northern blot and dot blot analysis was used to quantify G-protein mRNA. It was shown that adriamycin did not induce any change in the total beta-adrenoceptor density, nor did the high affinity agonist binding to beta-adrenoceptor change. Adriamycin did not induce any alteration in the amount of mRNA encoding for stimulatory (Gs) or inhibitory (Gi) G-proteins. Also, basal and stimulated adenylyl cyclase activities were identical in the different experimental groups. In contrast, the Ca(2+)-ATPase was shown to increase in adriamycin-treated rats compared to control rats (45 +/- 3.8 versus 23 +/- 1.2 mumol Pi/mg/h, P less than .01). Metoprolol was shown to normalize this increase (29 +/- 2.1 mumol Pi/mg/h). Thus, it may be concluded that in experimental adriamycin-induced cardiotoxicity, despite Ca(2+)-overloading, the beta-adrenoceptor-G protein-adenylyl cyclase system remains intact. Metoprolol seems to prevent Ca(2+)-overloading independently of the beta-adrenoceptors studied here.
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| 15. |
- Fu, Michael, 1963, et al.
(författare)
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Functional autoimmune epitope on alpha 1-adrenergic receptors in patients with malignant hypertension.
- 1994
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Ingår i: Lancet. - 0140-6736. ; 344:8938, s. 1660-3
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Tidskriftsartikel (refereegranskat)abstract
- Because of the growing evidence that hypertensive disease is accompanied by immunological dysfunction, we have investigated autoimmunity in patients with malignant hypertension. Peptides corresponding to the sequence of the second extracellular loops of the human alpha 1-adrenergic receptor and the M2-muscarinic receptor were used as antigens in an ELISA. Serum from 4 (12%) of 33 healthy controls, 3 (20%) of 15 patients with malignant essential hypertension, and 7 (64%) of 11 with secondary hypertension showed positive responses in the ELISA for the alpha 1-adrenergic receptor peptide. Positive responses were significantly more common among the patients with secondary hypertension than in the other two groups (p < 0.01). By contrast, no autoantibodies against the M2-muscarinic receptor peptide were detected in either hypertensive group. Autoantibodies against the alpha 1-adrenergic receptor, affinity-purified from patients with positive responses, specifically recognised bands with molecular masses of 68, 40, and 37 kDa on immunoblotted membrane proteins of rat ventricles. The patients' autoantibodies caused a decrease in tritiated prazosin binding sites and an increase in heart beating frequency of neonatal cultured rat cardiomyocytes; antibodies purified from the controls had no effect. Circulating autoantibodies against the alpha 1-adrenergic receptor are present in a subgroup of patients with malignant hypertension. These autoantibodies have pharmacological activity in vitro, which suggests that they may be involved in the pathogenesis of malignant hypertension.
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| 16. |
- Fu, Michael, 1963, et al.
(författare)
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Gi-mediated muscarinic adenylyl cyclase inhibition in timolol-treated stunned porcine myocardium.
- 1994
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Ingår i: Acta physiologica Scandinavica. - 0001-6772. ; 151:3, s. 291-9
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Tidskriftsartikel (refereegranskat)abstract
- The Gi-mediated muscarinic receptor-adenylyl cyclase system was examined in stunned myocardium induced by either three or five brief ischaemic periods after beta-adrenoceptor blockade by timolol (0.1 mg kg-1). The mid-left anterior descending coronary artery was occluded for 2, 10 and 2 min in four pigs, and for 2, 2, 5, 10 and 2 min in four other pigs. All the ischaemic periods were separated by 30 min of reperfusion and the biopsies were obtained 60 min after the last ischaemic period. Segment length function was measured in the ischaemic region and in the control region supplied by the left circumflex artery. In the two groups, the percentage systolic shortening was reduced equally, to 59 +/- 9 and 58 +/- 10% of control in the region subjected to ischaemia and only minimally in the control region. The biopsies from the stunned region from both groups showed: (1) no change in either the affinity for carbachol or the number of binding sites of the muscarinic receptors; (2) no alterations in messenger RNA encoding for the alpha subunit-2 of the inhibitory guanine nucleotide binding protein, as demonstrated by northern blot and solution hybridization; (3) no change in membrane-bound inhibitory guanine nucleotide binding protein, as shown by enzyme immunoassay utilizing a specific anti-peptide antibody, and (4) unchanged inhibition of stimulated adenylyl cyclase activity. These results suggest that there is an intact inhibitory guanine nucleotide binding protein-mediated muscarinic receptor adenylyl cyclase system in the stunned porcine myocardium.
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| 17. |
- Fu, Michael, 1963, et al.
(författare)
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Hypersensitivity of Gi protein mediated muscarinic receptor adenylyl cyclase in chronic ischaemic heart failure in the rat.
- 1993
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Ingår i: Cardiovascular research. - 0008-6363. ; 27:11, s. 2065-70
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim was to study the Gi protein mediated muscarinic signalling system in the myocardium of rats with chronic ischaemic heart failure. METHODS: Chronic ischaemic heart failure was induced by myocardial ischaemia (four weeks after coronary artery ligation) in rats. The densities and agonist affinities of muscarinic receptors, and the functional activity and concentration of Gi proteins were studied. RESULTS: In failing hearts, the activity of adenylyl cyclase stimulated by guanyliminodiphosphate (Gpp(NH)p) was decreased by 46%. Stimulated activities of adenylyl cyclase by both sodium fluoride and forskolin, however, remained unchanged. Carbachol depressed forskolin stimulated adenylyl cyclase more in membranes from failing hearts than those from normal hearts. The functional level of Gs protein as measured by a reconstitution assay in sarcolemmal membrane did not differ between the two groups. Furthermore, muscarinic receptors exhibited superhigh and low affinities for agonist in failing hearts whereas those in control hearts displayed only high and low affinities. No significant difference in the peptide equivalent amount of membrane bound Gi protein was found in either group. CONCLUSIONS: The experimental chronic failing heart due to myocardial ischaemia showed a depressed myocardial adenylyl cyclase signalling system. This may be due to the hypersensitivity of the Gi protein mediated muscarinic receptor-adenylyl cyclase system as shown by the increased inhibition of Gpp(NH)p mediated adenylyl cyclase, more potent inhibition of stimulated adenylyl cyclase by carbachol, and the superhigh affinity of the muscarinic receptors for carbachol.
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| 18. |
- Fu, Michael, 1963, et al.
(författare)
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Immunocytochemical localization of M2 muscarinic receptors in rat ventricles with anti-peptide antibodies.
- 1994
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Ingår i: The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society. - 0022-1554. ; 42:3, s. 337-43
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Tidskriftsartikel (refereegranskat)abstract
- We produced antibodies against a synthetic peptide corresponding to amino acids 168-192 of the second extracellular loop of the M2 human muscarinic receptor in rabbits. In immunoblot, affinity-purified antibodies specifically recognized a major band of rat ventricular muscarinic receptor protein with a molecular weight of about 80 KD. This recognition could be blocked by pre-incubation with peptide. Moreover, with both light (LM) and electron microscopic (EM) immunocytochemistry techniques, muscarinic receptors were detected on sarcolemma and T-tubules of rat cardiomyocytes. In addition, immunoreactions were localized in membranes of capillaries. Likewise, these reactivities were abolished by pre-incubation with peptide. These results suggest that the antibodies against the second extracellular loop of human M2 muscarinic receptor could specifically recognize rat ventricular muscarinic receptor protein and could be a powerful tool to study the fate of this receptor under different pathological or physiological conditions.
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| 19. |
- Fu, Michael, 1963, et al.
(författare)
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Immunohistochemical localization of angiotensin II receptors (AT1) in the heart with anti-peptide antibodies showing a positive chronotropic effect.
- 1998
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Ingår i: Receptors & channels. - 1060-6823. ; 6:2, s. 99-111
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Tidskriftsartikel (refereegranskat)abstract
- Antibodies were produced against a synthetic peptide corresponding to amino acids (165-191) of the second extracellular loop of the human angiotensin II receptor subtype 1 (AT1) in rabbits. The purified antibodies had an apparent affinity of about 1 nM and were monospecific for the AT1-receptor peptide. Chemical modification of the carboxyl groups (glu at positions 173 and 185) and the sulfhydryl group (cys at position 180) of the AT1-receptor peptide did not alter the relative affinity of the coated AT1-receptor peptide to antibodies. The antibodies specifically stained CHO cells expressing the rat AT1a receptor. Immunoblots on rat kidney revealed that the antibody recognized a protein band of 59 +/- 3 kDa in a dose-dependent manner and this band was no longer detected after preincubating the antibodies with AT1-receptor peptide. Using electron microscopic and immunofluorescence immunocytochemistry techniques, angiotensin II receptors were detected in (1) the sarcolemma, T-tubules and nuclei of rat cardiomyocytes, (2) the transluminal side of endothelial cells and (3) fibroblast cells. These localizations are specific, as the immunostaining did not appear when preimmune rabbit serum was used and was blocked after preincubating antibodies with antigenic peptide. Functionally, these antibodies did not affect the ligand binding properties of the receptors but displayed agonist-like activity as shown by dose-dependent increases in beating frequency in cultured neonatal cardiomyocytes. These results suggest that the antibodies against the second extracellular loop of human AT1 receptors were able to specifically recognize AT1 receptors. In addition, they extend the observation that the second extracellular loop of the G-protein coupled membrane receptors is a specific target for antibodies with agonist-like activity.
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| 20. |
- Fu, Michael, 1963, et al.
(författare)
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Increase in functional activity rather than in amount of Gi-alpha in failing human heart with dilated cardiomyopathy.
- 1992
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Ingår i: Cardiovascular research. - 0008-6363. ; 26:10, s. 950-5
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim was to investigate whether or not increased pertussis toxin catalysed ADP ribosylation correlates with increased amount of Gi-alpha in failing human heart. DESIGN: Antisera raised against unique synthetic peptides corresponding to alpha subunits of Gs and Gi 1-3 were used in immunoblotting and ELISA to determine amounts of various G proteins. Adenylyl cyclase activity, beta adrenoceptors, and muscarinic receptors were then measured in cardiomyopathic hearts (n = 6) obtained at transplant in order to study whether or not an altered expression of G proteins has relevance to the integrity and function of the receptor--adenylyl cyclase system. Six non-failing control hearts were also studied. RESULTS: No significant differences in the peptide equivalent amounts of either Gs or Gi were found in the failing human heart as compared to the non-failing heart. However, functional activity of Gi was shown to increase significantly since there was a decrease in basal (57%), isoprenaline stimulated (60%), and guanyliminodiphosphate stimulated (52%) adenylyl cyclase activity. In contrast the density of beta adrenoceptors was markedly decreased (51%) in failing human heart in comparison to non-failing hearts. Neither the density nor the affinity of muscarinic receptors changed in the failing human heart. CONCLUSION: These results suggest that in the failing human heart, there is an increase in functional activity rather than in amount of Gi, and an important part of functional expression of Gi-alpha may be regulated at the post-translational level.
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| 21. |
- Fu, Michael, 1963, et al.
(författare)
-
Localization of a functional autoimmune epitope on the muscarinic acetylcholine receptor-2 in patients with idiopathic dilated cardiomyopathy.
- 1993
-
Ingår i: The Journal of clinical investigation. - 0021-9738. ; 91:5, s. 1964-8
-
Tidskriftsartikel (refereegranskat)abstract
- A peptide corresponding to the sequence 169-193 of the second extracellular loop of the human muscarinic acetylcholine receptor-2 was used as an antigen to screen sera from patients with idiopathic dilated cardiomyopathy (DCM, n = 36) and healthy blood donors (HBD, n = 40). The sera from 14 patients with DCM (38.8%) and 3 HBD (7.5%) recognized the muscarinic receptor peptide at dilutions varying from 1:20 to 1:160 in ELISA. A highly significant correlation (P = 0.006) was found between the presence of antimuscarinic receptor-2 autoantibodies and anti-beta-adrenoceptor-1 autoantibodies in the patients' sera. Affinity-purified autoantibodies from positive sera of patients with DCM recognized on the electrotransferred protein of rat ventricular membrane a major band of about 80 kD. Incubation of autoantibodies with membrane resulted not only in a decrease in the maximal binding sites (Bmax) but also in an increase in Kd of radioligand binding in a concentration-dependent manner. This suggests a mixed-type of inhibition. Moreover, preincubation with atropine abolished the inhibitory effect of autoantibodies on the receptor binding whereas carbachol appeared to have no effect on the activity of the autoantibodies. These data define a subgroup of patients with idiopathic DCM who have in their sera functionally active autoantibodies against muscarinic receptor-2.
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| 22. |
- Fu, Michael, 1963, et al.
(författare)
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Myocardial hypertrophy in transgenic mice overexpressing the bovine growth hormone (bGH) gene.
- 2000
-
Ingår i: Journal of internal medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 247:5, s. 546-52
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The main purpose of the present study was to characterize cardiac muscle hypertrophy using both qualitative and quantitative microscopy in mice overexpressing the bovine growth hormone. RESULTS: Measurements of 30 fibres from each group revealed that fibre diameter in transgenic hearts was significantly larger than in control hearts. There was a significant decrease in interfibrillar space in transgenic hearts as compared with control hearts. The enlarged transgenic hearts displayed unchanged organelles such as normal myofibrils and mitochondria in a normal pattern, suggesting balanced growth. Myelin structures were occasionally observed between normal myofibrils. Moreover, myocardial beta-adrenergic receptors and muscarinic receptors in the hearts of transgenic mice overproducing GH were studied to see whether they are involved in the hypertrophic process. It was shown that the density of muscarinic receptors had decreased and the super-high affinity of muscarinic receptors was lost, without any significant changes in either the density or the affinity of beta-adrenergic receptors, as compared with controls. CONCLUSIONS: These results demonstrate that a GH excess was able to induce significant myocardial hypertrophy and that there was a downregulation of muscarinic receptors.
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| 23. |
- Fu, Michael, 1963, et al.
(författare)
-
Oxygen free radical injury and Gs mediated signal transduction in the stunned porcine myocardium.
- 1992
-
Ingår i: Cardiovascular research. - 0008-6363. ; 26:5, s. 449-55
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim was to investigate involvement of oxygen free radicals and any changes in the Gs mediated beta adrenergic signalling system of stunned porcine myocardium. METHODS: Myocardial stunning was induced in eight pentobarbitone anaesthetised pigs by brief occlusions of the distal left anterior descending coronary artery for periods of up to 10 min. Segment length function was measured in the ischaemic region and in a control region supplied by the circumflex artery. Left ventricular biopsies were obtained from the two regions 1 h after the last occlusion for ultrastructural and biochemical studies. Timolol has been used to prevent arrhythmia during ischaemia. RESULTS: At the time when biopsies were obtained, percent systolic shortening was reduced to 58% in the region subjected to ischaemia and was only minimally reduced in the control region. In the biopsies from the stunned region: (1) electron microscopy showed mild and reversible intracellular changes in the stunned myocardium; (2) the activities of superoxide dismutase and glutathione peroxidase were decreased by 66% and 52%, respectively; (3) the content of malondialdehyde was increased by 49%; (4) neither density nor affinity of beta adrenoceptors showed any changes; (5) there were no alterations in messenger RNA encoding for the alpha subunit of the stimulatory guanine nucleotide binding protein (Gs), demonstrated by northern and dot-blot hybridisations; (6) ELISA technique utilising a specific antipeptide antibody showed no quantitative change in Gs; (7) the activity of adenyl cyclase was unchanged. CONCLUSIONS: Even though the stunned porcine myocardium showed substantial evidence of free radical injury, the beta adrenergic signalling system was intact.
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| 24. |
- Guillet, J G, et al.
(författare)
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Induction of a pharmacologically active clonotypic B cell response directed to an immunogenic region of the human beta 2-adrenergic receptor.
- 1992
-
Ingår i: Clinical and experimental immunology. - 0009-9104. ; 89:3, s. 461-7
-
Tidskriftsartikel (refereegranskat)abstract
- It has been reported that autoantibodies against the beta 2-adrenergic receptors are involved in the pathology of allergic disorders and of Chagas' disease. Therefore, the immune response against a peptide (H26Q) corresponding to the putative second extracellular loop of the human beta 2-adrenergic receptor, which could be a target for autoantibody attack, was analysed in view of its possible immunogenicity. The free peptide induced a T cell-mediated humoral response in the context of three different murine MHC haplotypes. The T cell epitope was found to be localized in the N-terminal region of the peptide. Highly specific T helper cells were capable of stimulating B cells with the potential to generate a large antibody repertoire reactive with the loop peptide. MoAbs were screened to analyse this B cell response for antibodies potentially interfering with receptor function and a MoAb was found that impaired ligand binding to the receptor.
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| 25. |
- Lustig, Florentina, 1948, et al.
(författare)
-
Alternative splicing determines the binding of platelet-derived growth factor (PDGF-AA) to glycosaminoglycans.
- 1996
-
Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 35:37, s. 12077-85
-
Tidskriftsartikel (refereegranskat)abstract
- We have shown previously that the platelet-derived growth factor (PDGF) and a synthetic oligopeptide, corresponding to the basic carboxyl-terminal amino acid extension of the long PDGF-A isoform, bind to heparin. Here, we have expressed the long (rA125) and the short (rA109) variants of PDGF A-chains in Escherichia coli and produced the functional homodimers. Surface plasmon resonance analyses showed that while the dimeric rA125 bound with high affinity to low molecular weight heparin, the rA109, lacking the basic extension, did not. This strongly indicated that high affinity binding is due to the carboxyl-terminal extension. Investigations of kinetics and thermodynamics suggested an allosteric binding mechanism. Thus, dimeric rA125 contains two equivalent binding sites. Following low affinity binding of heparin to one binding site, the dimer undergoes a conformational change, increasing the affinity for heparin about 40 times. This positive cooperativity requires the basic amino acid extension in both monomers of the dimeric PDGF molecule. Thermodynamics of the reaction, showing an entropy-driven endothermic process, suggest the involvement of hydrophobic interactions in this rearrangement. Three amino acids in the basic carboxyl-terminal extension were essential for the interaction: the basic residues Arg111 and Lys116, and the polar Thr125. We also found that other glycosaminoglycan species, corresponding to those produced by human arterial smooth muscle cells, bound to dimeric rA125 and that heparan sulfate showed the highest affinity.
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| 26. |
- Lustig, Florentina, 1948, et al.
(författare)
-
Processing of PDGF gene products determines interactions with glycosaminoglycans.
- 1999
-
Ingår i: Journal of molecular recognition : JMR. - 0952-3499. ; 12:2, s. 112-20
-
Tidskriftsartikel (refereegranskat)abstract
- The platelet derived growth factor (PDGF), a mitogen for mesenchymal cells, may be bound to and inhibited by heparin and other glycosaminoglycans. PDGF is a homo- or heterodimer of A- and B-chains. They occur as short (A109 and B110) and long (A125 and B160) isoforms. The latter contain basic carboxyl-terminal extensions. Dimeric A125 binds to heparin through its basic extension in a two-step reaction. The mechanism involves a conformational change and is consistent with a Monod-Wyman-Changeux allosteric model. Previous indirect experiments suggested that three critical amino acids (basic R111, K116 and polar T125) might be involved. Here, direct binding experiments using dimeric full-length mutants in surface plasmon resonanse analysis showed that all three critical amino acids in an R(X)4K(X)8T-motif contributed in a concerted manner to the high affinity binding. Mutations of these amino acids to alanine resulted in large thermodynamic changes, loss of the allosteric mechanism and order(s) of magnitude lower binding affinity. The binding mechanism and affinity of long dimeric rB were similar to the mutants. Short dimeric rA109 and rB110 showed 100 times lower binding affinity than rA125. Consequently, interactions with glycosaminoglycans in tissues varies between PDGF isoforms and may influence their local accumulation and activity.
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| 27. |
- Magnusson, Yvonne, 1957, et al.
(författare)
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Antigenic analysis of the second extra-cellular loop of the human beta-adrenergic receptors.
- 1989
-
Ingår i: Clinical and experimental immunology. - 0009-9104. ; 78:1, s. 42-8
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Tidskriftsartikel (refereegranskat)abstract
- Polyclonal antibodies were raised in rabbits by immunization with free peptides corresponding to positions 197-222 of the human beta 1-adrenergic receptor (beta 1 peptide) and the corresponding sequence (172-197) of the human beta 2-adrenergic receptor (beta 2 peptide). While the beta 2 peptide yielded antibodies that cross-reacted with the beta 1 peptide, the antibodies against the beta 1 peptide did not cross-react with the beta 2 sequence. Cross-reactivity of the anti-beta 2 peptide antibodies and the selectivity of the anti-beta 1 peptide antibodies were also revealed in the recognition by immunoblots of the beta 1- and beta 2-adrenergic receptors of different species or of the receptor gene products expressed in a bacterial vector. These antibodies could be used immunohistochemically to visualize the beta-adrenergic receptors on rabbit heart. The anti-beta 2 peptide antibodies did not show any functional effect on the beta-adrenergic receptors; the anti-beta 1 peptide antibodies were able to displace agonist affinity to higher values. Recognition of truncated peptides by the anti-beta 1 and anti-beta 2 peptide antibodies suggested that the cross-reaction of the anti-beta 2 peptide antibodies was due to the recognition of a common epitope on the C-terminal part of the peptides. The anti-beta 1 peptide antibodies recognized the N-terminal part of the peptide better than the C-terminal part. These results suggest that the second extracellular loop postulated in the structure of the human beta-adrenergic receptor contains the T and B cell epitopes necessary for induction of an immune response. The selectivity and the functional properties of the antibodies raised against that loop in the beta 1 adrenergic receptor could have relevance in induction of auto antibodies in certain cardiomyopathic conditions.
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| 28. |
- Magnusson, Yvonne, 1957, et al.
(författare)
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Autoimmunity in idiopathic dilated cardiomyopathy. Characterization of antibodies against the beta 1-adrenoceptor with positive chronotropic effect.
- 1994
-
Ingår i: Circulation. - 0009-7322. ; 89:6, s. 2760-7
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Autoantibodies against the beta 1-adrenoceptor have been detected in the sera of patients with idiopathic dilated cardiomyopathy (DCM). The mechanisms by which these autoantibodies can alter normal receptor function are investigated, and the results are interpreted in the light of the beneficial effects of beta 1-blockade in some of these patients. METHODS AND RESULTS: Autoantibodies against the beta 1-adrenoceptor, affinity purified from sera of patients with idiopathic DCM, were analyzed in a functional test system of spontaneously beating neonatal rat heart myocytes. Antibodies from rabbits immunized with peptides derived from the amino acid sequence of this receptor were also analyzed. Autoantibodies, against the second extracellular loop increased the beating frequency of isolated myocytes in a concentration-dependent manner, to approximately 80% of maximal isoproterenol stimulation. Rabbit anti-peptide antibodies against the second extracellular loop increased the beating frequency correspondingly. Autoantibodies and rabbit anti-peptide antibodies against the second extracellular loop were able to immunoprecipitate the unliganded receptor but not the antagonist-occupied receptor. In contrast, rabbit antibodies against the extracellular N-terminal sequence 34-57 of the beta 1-adrenoceptor were able to immunoprecipitate both the unliganded and the antagonist-occupied receptor although with no effect on the beating frequency of myocytes. The positive chronotropic effect of the antibodies was completely neutralized both by the addition of increasing concentrations of the beta 1-selective antagonist bisoprolol and by preincubation with the peptide corresponding to the second extracellular loop. The antibody-induced increase in beating frequency remained unchanged for more than 6 hours. This should be compared with the isoproterenol-stimulated beating frequency, which undergoes desensitization within 60 minutes. Addition of isoproterenol to autoantibody-stimulated myocytes resulted in only a small increase in beating frequency and did not cause desensitization. Antibodies had only a marginal effect on cyclic AMP production of stimulated cardiomyocytes compared with the 10-fold increase obtained after stimulation with isoproterenol. CONCLUSIONS: The second extracellular loop of the beta 1-adrenoceptor is a specific target for antibodies with stimulatory activity detected in patients with idiopathic DCM. The antibodies have a positive chronotropic effect on isolated rat heart myocytes. Autoantibody stimulation does not cause the normal agonist-induced desensitization phenomena of the effector system. These findings could contribute to our understanding of the pathophysiological mechanisms of the autoantibodies and of the beneficial effect of beta 1-blocking agents in the treatment of patients with idiopathic DCM.
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| 29. |
- Magnusson, Yvonne, 1957, et al.
(författare)
-
Beta 1-adrenoceptor autoimmunity in cardiomyopathy.
- 1996
-
Ingår i: International journal of cardiology. - 0167-5273. ; 54:2, s. 137-41
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Forskningsöversikt (refereegranskat)abstract
- A growing body of studies have confirmed that autoantibodies against beta 1-adrenoceptors are present in different types of cardiomyopathy. This suggests that they play a role in the pathophysiology of the disease. This article will review the data indicating the presence of anti-beta 1-adrenoceptor autoantibodies in cardiomyopathy. It will focus upon their structural and functional properties which could explain their possible role in the induction and development of cardiomyopathic diseases.
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| 30. |
- Magnusson, Yvonne, 1957, et al.
(författare)
-
Functional analysis of rabbit anti-peptide antibodies which mimic autoantibodies against the beta 1-adrenergic receptor in patients with idiopathic dilated cardiomyopathy.
- 1991
-
Ingår i: Journal of autoimmunity. - 0896-8411. ; 4:6, s. 893-905
-
Tidskriftsartikel (refereegranskat)abstract
- A synthetic peptide corresponding to the second extracellular loop of the beta 1-adrenergic receptor was used as an antigen for antibody production in three rabbits. Antibodies of high titers were obtained in all rabbits. Only one rabbit yielded antibodies which decreased radioligand binding on the receptor in a similar way to that described for autoantibodies in patients with dilated cardiomyopathy. These antibodies recognized the receptor protein in immunoblots. Epitope mapping indicated that the N-terminal sequence of the loop used as antigen was the target of the major antigen fraction. Incubation of antibodies with C6 glioma cell membranes or inner membranes of E. coli, which express the human beta 1-adrenergic receptor, resulted in a decrease in number of radioligand binding sites. This decrease was dependent on the concentration of antibody and of Mg++ ions. It was not affected by the GTP analog GppNHp or the beta 1 subtype-specific antagonist metoprolol. The agonist, isoproterenol, also induced a decrease but the effects of antibody and agonist were not additive. These results suggest that the antibodies induce a Mg(++)-dependent, 'active', labile conformation of the receptor, independent from coupling to the GTP regulatory protein, but similar to that induced by the agonist isoproterenol. This interpretation was corroborated by the beta 1-adrenergic receptor agonist-like effect of the antibodies on cardiomyocytes in culture.
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| 31. |
- Magnusson, Yvonne, 1957, et al.
(författare)
-
Mapping of a functional autoimmune epitope on the beta 1-adrenergic receptor in patients with idiopathic dilated cardiomyopathy.
- 1990
-
Ingår i: The Journal of clinical investigation. - 0021-9738. ; 86:5, s. 1658-63
-
Tidskriftsartikel (refereegranskat)abstract
- The presence and properties of serum autoantibodies against beta-adrenergic receptors in patients with idiopathic dilated cardiomyopathy were studied using synthetic peptides derived from the predicted sequences of the human beta-adrenergic receptors. Peptides corresponding to the sequences of the second extracellular loop of the human beta 1- and beta 2-adrenergic receptors were used as antigens in an enzyme immunoassay to screen sera from patients with dilated cardiomyopathy (n = 42), ischemic heart disease (n = 17), or healthy blood donors (n = 34). The sera of thirteen dilated cardiomyopathy patients, none of the ischemic heart disease patients, and four of the healthy controls monospecifically recognized the beta 1-peptide. Only affinity-purified antibodies of these patients had a inhibitory effect on radioligand binding to the beta 1 receptor of C6 rat glioma cells. They recognized the receptor protein by immunoblot and bound in situ to human myocardial tissue. We conclude that a subgroup of patients with idiopathic dilated cardiomyopathy have in their sera autoantibodies specifically directed against the second extracellular loop of the beta 1-adrenergic receptor. These antibodies could serve as a marker of an autoimmune response with physiological and/or pathological implications.
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| 32. |
- Matsui, S, et al.
(författare)
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Peptides derived from cardiovascular G-protein-coupled receptors induce morphological cardiomyopathic changes in immunized rabbits.
- 1997
-
Ingår i: Journal of molecular and cellular cardiology. - : Elsevier BV. - 0022-2828. ; 29:2, s. 641-55
-
Tidskriftsartikel (refereegranskat)abstract
- An experimental model of early-stage cardiomyopathy was created by immunizing rabbits for 1 year with synthetic peptides corresponding to the sequence of the second extracellular loop of either beta-adrenoceptors or M2-muscarinic receptors. Thirty male rabbits were used and divided into three groups: a control group (n = 10), a group immunized with the peptide corresponding to the beta-adrenoceptor (beta 1 group) (n = 10) and a group immunized with the peptide corresponding to the M2-muscarinic receptor (M2 group) (n = 10). If the sera from both groups of immunized rabbits high-titres of anti-peptide antibodies were found throughout the study period but not in the sera from control rabbits or in the preimmune sera of immunized rabbits. No significant cross-reaction with peptides other than those used for immunization was found. The myocardial receptor density of both immunized groups displayed a strong trend toward receptor up-regulation. This was significant in the beta 1 group but not in the M2 group. Both groups of immunized rabbits displayed significantly enlarged ventricles and thinner walls, as compared with the control group. However, in contrast to the beta 1 group, which showed enlarged cavities in both left and right ventricles, the M2 group was mainly affected in the right ventricles. Moreover, morphological examinations of the hearts of rabbits from both immunized groups demonstrated focal myofibrillar lysis, loss of myofilament, mitochondrial swelling and condensation, sarcoplasmic vacuolation, deposition of dense granules in the sarcoplasm and the myofibrils. One of the sex control rabbit hearts which were examined showed mild degenerative changes in the myocardium and scant mononuclear cell infiltration. However, when all the control rabbit hearts were examined by electron microscopy, no significant alterations were found. These results suggest that immunization by peptides, corresponding to the target sequences for anti-receptor autoantibodies in idiopathic dilated cardiomyopathy, induces morphological changes in the heart similar to those found in the human disease.
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| 33. |
- Mobini, Reza, 1965, et al.
(författare)
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A monoclonal antibody directed against an autoimmune epitope on the human beta1-adrenergic receptor recognized in idiopathic dilated cardiomyopathy.
- 2000
-
Ingår i: Hybridoma. - : Mary Ann Liebert Inc. - 0272-457X. ; 19:2, s. 135-42
-
Tidskriftsartikel (refereegranskat)abstract
- A monoclonal antibody (MAb M16) was obtained by immunizing Balb/C mice with free peptide H26R, corresponding to the second extracellular loop of the human beta1-adrenergic receptor (beta1AR), against which functional autoantibodies have been detected in patients with idiopathic dilated cardiomyopathy. The MAb was found to be of IgG2b type and directed against a conformational epitope, encompassing the sequence recognized by the human autoantibodies. BIAcore measurements yielded an equilibrium constant of 6.5 X 10(7) M1 with an association rate constant (kon) of 6.5 X 10(4) M(-1) sec(-1) and a dissociation rate constant (koff) of 1.0 X 10(-3) sec(-1). It immunoprecipitated only poorly the solubilized beta1AR of Sf9 cell membranes. Functionally, the MAb was capable of not only reducing the number of the maximal binding sites to the beta1-adrenergic receptor of transfected Sf9 cell membranes, but also of displaying a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These properties, which the MAb shares with the human autoantibodies, makes it an interesting tool for passive transfer studies in mice.
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| 34. |
- Mobini, Reza, 1965, et al.
(författare)
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Probing the immunological properties of the extracellular domains of the human beta(1)-adrenoceptor.
- 1999
-
Ingår i: Journal of autoimmunity. - : Elsevier BV. - 0896-8411. ; 13:2, s. 179-86
-
Tidskriftsartikel (refereegranskat)abstract
- The human beta(1)-adrenoceptor is an immune target for autoantibodies with functional activity in cardiovascular diseases. Different epitopes on the extracellular domains of the receptor are involved. To study the immunological and pharmacological properties of these epitopes, rabbits were immunized with peptides corresponding to a large domain in the N-terminal part of the receptor and to its first and second extracellular loops. In contrast to the two other peptides, the first extracellular loop did not have immunogenic properties but acted as a hapten. Antibodies affinity-purified with the three synthetic peptides were able to significantly immunoprecipitate the solubilized receptor, confirming that they recognized the target receptor. While antibodies against the N-terminal domain did not inhibit the binding of a radiolabelled antagonist to the receptor, those against the first and second extracellular loop showed non-competitive inhibition. Similarly, only the two latter antibodies exerted a specific agonist-like effect on the receptor, as assessed on neonatal rat cardiomyocytes in culture. Our results are in accordance with those found for human anti-receptor autoantibodies with functional effects. We conclude that not all extracellular epitopes give rise to functional autoantibodies with potential physiopathological relevance in cardiac diseases with an autoimmune component.
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| 35. |
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| 36. |
- Skomedal, T, et al.
(författare)
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Anti-M2 muscarinic receptor antibodies inhibit beta-adrenoceptor-mediated inotropic response in rat myocardium.
- 1997
-
Ingår i: European journal of pharmacology. - 0014-2999. ; 333:2-3, s. 169-75
-
Tidskriftsartikel (refereegranskat)abstract
- The modulation of the inotropic effect by affinity-purified antibodies against a synthetic peptide corresponding to the second extracellular loop of the human muscarinic M2 receptors was studied in adult rat ventricular myocardium. These anti-muscarinic M2 receptor antibodies shifted the dose-response relationship of the beta-adrenoceptor agonist isoproterenol to higher concentrations whereas preimmune rabbit immunoglobulin G (IgG) or antibodies against the N-terminus of the beta 1-adrenoceptor had no effect. This effect of anti-muscarinic M2 receptor antibodies was fully blocked after preincubation with the antigenic peptide. No significant change of maximal inotropic response to isoproterenol was observed in the presence of anti-muscarinic M2 receptor antibodies. The anti-muscarinic M2 receptor antibodies did apparently not hamper the access of the muscarinic receptor agonist carbachol. The muscarinic receptor antagonist atropine attenuated the effect of the anti-muscarinic M2 receptor antibodies. The present study demonstrates for the first time in intact adult ventricular myocardium a specific stimulatory muscarinic activity of antibodies raised against a part of the muscarinic M2 receptor protein.
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| 37. |
- Tate, K, et al.
(författare)
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Epitope analysis of T- and B-cell response against the human beta 1-adrenoceptor.
- 1994
-
Ingår i: Biochimie. - 0300-9084. ; 76:2, s. 159-64
-
Tidskriftsartikel (refereegranskat)abstract
- Several reports have recently raised the possible significance of the presence of autoantibodies against the beta 1-adrenoceptor in patients with idiopathic dilated cardiomyopathy. An investigation was thus initiated to study the immune response against this receptor at the T-cell and the B-cell level. Using membranes of E coli transfected with the human beta 1-adrenoceptor gene as immunogen, T-helper cells of the immunized mice were stimulated with synthetic peptides derived from the receptor and predicted to be immunogenic to assess the T-cell immunodominant regions of the receptor. Three peptides derived from the second transmembrane region, from the second extracellular loop and from the C-terminal domain were shown to be stimulatory. Synthetic peptides, derived from two domains of the receptor which could be potential targets for autoantibodies, yielded an antibody response after immunization with the free peptides. The peptide derived from the N-terminal region yielded antibodies which recognized the receptor in immunoblot and by immunoprecipitation but they had no functional effect on the receptor. The peptide derived from the second extracellular loop yielded antibodies which recognized the receptor in immunoblot and by immunoprecipitation of the free receptor and which had a pharmacological effect on the receptor. The second extracellular loop thus contains T- and B-cell epitopes which could be involved in the autoimmune process.
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| 38. |
- Tunbäck, Petra, 1965, et al.
(författare)
-
Type-specific reactivity of anti-glycoprotein G antibodies from herpes simplex virus-infected individuals is maintained by single or dual type-specific residues.
- 2005
-
Ingår i: The Journal of general virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 86:Pt 2, s. 247-51
-
Forskningsöversikt (refereegranskat)abstract
- Glycoprotein G-1 (gG-1) of herpes simplex virus type 1 (HSV-1) and gG-2 of HSV-2 are the only known HSV proteins that induce type-specific human antibody responses. Recently, it was shown that purified human anti-gG-1 and anti-gG-2 antibodies presented a type-specific reactivity to immunogenic stretches with high similarity between gG-1 and gG-2. In this study, the molecular basis for this type-specific recognition was investigated employing synthetic peptides covering the indicated regions, including substitutions of the type-specific residues. The results revealed that single or dual type-specific residues localized within regions of high similarity could induce significant structural differences, explaining the type-specific recognition of the human antibody response to the gG proteins.
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| 39. |
- van Gool, Jan D, et al.
(författare)
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Multi-center randomized controlled trial of cognitive treatment, placebo, oxybutynin, bladder training, and pelvic floor training in children with functional urinary incontinence.
- 2014
-
Ingår i: Neurourology and Urodynamics. - : Wiley. - 0733-2467. ; 33:5, s. 482-487
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Functional urinary incontinence causes considerable morbidity in 8.4% of school-age children, mainly girls. To compare oxybutynin, placebo, and bladder training in overactive bladder (OAB), and cognitive treatment and pelvic floor training in dysfunctional voiding (DV), a multi-center controlled trial was designed, the European Bladder Dysfunction Study. METHODS: Seventy girls and 27 boys with clinically diagnosed OAB and urge incontinence were randomly allocated to placebo, oxybutynin, or bladder training (branch I), and 89 girls and 16 boys with clinically diagnosed DV to either cognitive treatment or pelvic floor training (branch II). All children received standardized cognitive treatment, to which these interventions were added. The main outcome variable was daytime incontinence with/without urinary tract infections. Urodynamic studies were performed before and after treatment. RESULTS: In branch I, the 15% full response evolved to cure rates of 39% for placebo, 43% for oxybutynin, and 44% for bladder training. In branch II, the 25% full response evolved to cure rates of 52% for controls and 49% for pelvic floor training. Before treatment, detrusor overactivity (OAB) or pelvic floor overactivity (DV) did not correlate with the clinical diagnosis. After treatment these urodynamic patterns occurred de novo in at least 20%. CONCLUSION: The mismatch between urodynamic patterns and clinical symptoms explains why cognitive treatment was the key to success, not the added interventions. Unpredictable changes in urodynamic patterns over time, the response to cognitive treatment, and the gender-specific prevalence suggest social stress might be a cause for the symptoms, mediated by corticotropin-releasing factor signaling pathways. Neurourol. Urodynam. © 2013 Wiley Periodicals, Inc.
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| 40. |
- Vande Walle, Johan GJ, et al.
(författare)
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A new fast-melting oral formulation of desmopressin : A pharmacodynamic study in children with primary nocturnal enuresis
- 2006
-
Ingår i: BJU International. - 1464-4096 .- 1464-410X. ; 97:3, s. 603-609
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine the pharmacodynamic properties of a new oral lyophilisate formulation of desmopressin (in single doses of 30, 60, 120, 240, 360 or 480 μg) in children with known primary nocturnal enuresis (PNE) and thus identify those dosages that could provide a duration of action corresponding to a typical length of night-time sleep in children with PNE, additional objectives were to determine the safety and tolerability of desmopressin in this population. PATIENTS AND METHODS: Children with PNE (mean three or more wet nights/week), aged 6-12 years, were randomized into a double-blind, placebo-controlled study. An overhydration technique was used before dosing to suppress endogenous vasopressin production and thereby ensure that any antidiuresis could be attributed to treatment. Dosing with desmopressin or placebo occurred when urinary production was >0.13 mL/min/kg. Urinary volume, osmolality and duration of urinary-concentrating action (above three threshold levels: 125, 200 and 400 mOsm/kg) were determined as endpoints. RESULTS: All 72 participants receiving desmopressin had a pharmacodynamic response to the drug, while there was no change in urinary output in the 12 placebo-treated patients. There was a clear relationship between desmopressin dose and duration of action and osmolality during action, although the three highest-dose groups had similar results. The mean duration of action of desmopressin at the lowest osmolality threshold level was 3.6-10.6 h, according to dose, for the highest threshold, the values were 1.3-8.6 h. CONCLUSION: Desmopressin, as the oral lyophilisate, causes a marked decrease in urinary output in hydrated children with PNE. A small dose range (120-240 μg) is likely to control diuresis for a period corresponding to a night's sleep (7-11 h) in most children with PNE. However, some patients might require a higher dose to obtain antidiuresis for the complete night. © 2006 BJU International.
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| 41. |
- Vivier, Pierre-Hugues, et al.
(författare)
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Standardization of pediatric uroradiological terms : A multidisciplinary European glossary
- 2017
-
Ingår i: Journal of Pediatric Urology. - : Elsevier BV. - 1477-5131 .- 1873-4898. ; 13:6, s. 641-650
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- To promote the standardization of nephro-uroradiological terms used in children, the European Society of Pediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication among different clinicians involved in pediatric urology and nephrology.
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| 42. |
- Vivier, Pierre-Hugues, et al.
(författare)
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Standardization of pediatric uroradiological terms : a multidisciplinary European glossary
- 2018
-
Ingår i: Pediatric Radiology. - : SPRINGER. - 0301-0449 .- 1432-1998. ; 48:2, s. 291-303
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Tidskriftsartikel (refereegranskat)abstract
- To promote the standardization of nephro-uroradiological terms used in children, the European Society of Paediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication between different clinicians involved in pediatric urology and nephrology.
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| 43. |
- Wallukat, G, et al.
(författare)
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Agonistic effects of anti-peptide antibodies and autoantibodies directed against adrenergic and cholinergic receptors: absence of desensitization.
- 1996
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Ingår i: Blood pressure. Supplement. - 0803-8023. ; 3, s. 31-6
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Tidskriftsartikel (refereegranskat)abstract
- Affinity-purified autoantibodies and anti-peptide antibodies directed against the second extracellular loop of the beta 1-adrenoceptor increase the beating rate of cultured cardiomyocytes just like the beta-adrenergic agonist isoprenaline. Their positive chronotropic action is blocked by beta-adrenergic antagonists. Affinity-purified autoantibodies and anti-peptide antibodies directed against the muscarinic cholinergic M2 receptor exert in these myocytes, like the muscarinic cholinergic agent carbachol, a negative chronotropic effect that is antagonized by atropine. In contrast to the agonism of isoprenaline and carbachol, the described agonistic effects of the antibodies are not subject to desensitization.
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| 44. |
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| 45. |
- Zhao, R, et al.
(författare)
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Effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic acetylcholine receptors on transmembrane potentials and currents in guinea pig ventricular myocytes.
- 1996
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Ingår i: Molecular and cellular biochemistry. - 0300-8177. ; 163-164, s. 185-93
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Tidskriftsartikel (refereegranskat)abstract
- The effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic receptor on transmembrane potentials and currents in guinea pig single ventricular cells were analyzed using whole-cell patch clamp technique. These effects were compared with those of the muscarinic receptor agonists carbachol and acetylcholine. The antibodies shortened the action potential duration in a dose-dependent manner. By using a ramp or step rectangular pulse protocol, it was found that the antibodies increased the outward K+ current and decreased the inward basal ICa significantly. The reversal potential of both carbachol- and antibody-induced extra currents were close to -80 mV, being in proximity to the calculated Ek of -90 mV. A beta-adrenergic receptor agonist, isoprenaline, prolonged the action potential and increased the overshoot which could be inhibited by both antibody and carbachol. Isoprenaline increased inward ICa and outward Ik simultaneously. Both antibody and carbachol could significantly reduce the isoprenaline-stimulated ICa but not the isoprenaline-stimulated Ik. The antibody- or carbachol-induced outward K+ current and the depressant effects of antibody and carbachol on isoprenaline-stimulated ICa were partially antagonized by atropine. These results suggest that the anti-M2 muscarinic receptor antibodies display a stimulatory activity similar to muscarinic receptor agonist on the receptor-mediated electrophysiological events.
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| 46. |
- Östergren Lundén, Gunnel, 1950, et al.
(författare)
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Characterisation and application of antibodies specific for the long platelet-derived growth factor A and B chains.
- 2004
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Ingår i: The international journal of biochemistry & cell biology. - : Elsevier BV. - 1357-2725 .- 1878-5875. ; 36:11, s. 2226-41
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Tidskriftsartikel (refereegranskat)abstract
- The platelet-derived growth factor (PDGF) family comprises important mitogens for mesenchymal cells. The active dimeric form of PDGF consists of four structurally related A, B, C, and D chains. All PDGF-variants bind to PDGF-receptors. The A and B chains occur with and without basic C-terminal amino acid extensions as long (A(L) and B(L)) and short (A(S) and B(S)) isoforms. PDGF-A and -B form homo- or heterodimers. The biological relevance of short and long isoforms is unknown, although it may relate to different affinities for glycosaminoglycans of the cell glycocalix and intercellular matrix. Commercially available anti-PDGF-A and anti-PDGF-B antibodies cannot discriminate between the short and the long isoforms. Thus, to investigate the function of the long and short isoforms, we raised antibodies specific for the long A and B chain isoforms. The antibodies were affinity-purified and their properties analysed by surface plasmon resonance. Inhibition studies with different PDGF homodimers and dot-blot studies proved their high specificity for the respective isoforms. Both antibodies recognised the target PDGF homodimers complexed to the glycocalix of human arterial smooth muscle cells and human monocyte-derived macrophages. By using these specific antibodies, we were able to confirm at the protein level the synthesis of PDGF-A and -B during differentiation of human monocyte-derived macrophages and to demonstrate the presence of the PDGF-A(L) and PDGF-B(L) isoforms in human arterial tissue.
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