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Fuchs C, Armstrong VW, Quellhorst E, Scheler F. Prophylaxis and methods for early recognition of aluminium intoxication. Contrib Nephrol 2015; 38:81-94. [PMID: 6713903 DOI: 10.1159/000408070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Armstrong VW, Fuchs C, Klüver H, Nussbaumer D, Perl H, Rieger J, Scheler F. A synthetic resorcinol-formaldehyde resin for the absorption of urea from hemofiltrate. Contrib Nephrol 2015; 32:181-5. [PMID: 7128156 DOI: 10.1159/000406922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Fuchs C, Armstrong VW, Cremer P, Henning HV, Wieland H, Quellhorst E, Seidel D. An investigation of the lipoprotein profiles of patients on hemofiltration as compared to those on hemodialysis and intermittent peritoneal dialysis. Contrib Nephrol 2015; 32:92-6. [PMID: 7128167 DOI: 10.1159/000406910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Schultze FC, Petrova DT, Oellerich M, Armstrong VW, Asif AR. Differential proteome and phosphoproteome signatures in human T-lymphoblast cells induced by sirolimus. Cell Prolif 2010; 43:396-404. [PMID: 20590665 DOI: 10.1111/j.1365-2184.2010.00690.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES The present study was designed to investigate early proteome and phosphoproteome changes during inhibition of lymphocyte proliferation induced by sirolimus (SRL). MATERIALS AND METHODS Proliferation assays were conducted using human CCRF-CEM T lymphoblasts under different SRL concentrations. Total protein lysates after SRL treatment were used to identify significantly regulated proteins and phosphorylated proteins by 2-DE and Q-TOF Ultima Global mass spectrometer. RESULTS AND CONCLUSIONS Incubation with 2.5 micromol/l SRL resulted in a approximately 70% inhibition of cell proliferation. Cells incubated with 2.5 micromol/l for 30 min showed a differential phosphorylation pattern with one higher (TCPQ) and six lower phosphorylation signals (TBA1B, VIME, HNRPD, ENPL, SEPT9, PLSL). On investigating the differential protein expression, five proteins were found to be up-regulated (ECHB, PSB3, MTDC, LDHB and NDKA) and four were down-regulated (EHD1, AATC, LMNB1 and MDHC). Nine of these differentially regulated proteins/phosphoproteins (TCPQ, TBA1B, VIME, HNRPD, ENPL, ECHB, PSB3, LDHB and LMNB1) showed significant interaction potential, through binding protein YWHAZ using MINT software. CONCLUSIONS We report for the first time the simultaneous early influence of SRL on phosphorylation status and on protein expression in the total proteome of CCRF-CEM T lymphoblasts and predict that 56% of the proteins interact with each other, highlighting significance of these results.
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Affiliation(s)
- F C Schultze
- Department of Clinical Chemistry, University Medicine Goettingen, Goettingen, Germany
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Koehler SC, Von Ahsen N, Schlumbohm C, Asif AR, Goedtel-Armbrust U, Oellerich M, Wojnowski L, Armstrong VW. MarmosetCYP3A21, a model for humanCYP3A4: Protein expression and functional characterization of the promoter. Xenobiotica 2009; 36:1210-26. [PMID: 17162468 DOI: 10.1080/00498250600962831] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Due to its small size and the relative evolutionary proximity, the marmoset has been proposed as a model for studies of human drug interactions and metabolism. The current study investigated the expression and regulation of marmoset CYP3A using mass spectrometry and reporter gene techniques. Expression levels of hepatic marmoset CYP3A protein range from 51 to 123 pmol mg-1 total protein (mean 85.2 pmol mg-1, n = 10) and CYP3A21 is the dominant hepatic CYP3A protein in marmosets. The sequence similarity between human CYP3A4 and CYP3A21 across the first 7.5 kb of the cloned CYP3A21 promoter is 88% within the xenobiotic-responsive enhancer module (XREM) and the proximal promoter. Both regulatory modules confer transcriptional activation of CYP3A21-luciferase reporter gene constructs cotransfected with hPXR in intestinal LS174T cells. The pronounced response to rifampin and the moderate response to dexamethasone were similar to those observed with CYP3A4. Taken collectively, these data establish substantial similarities in expression and gene regulation between marmoset CYP3A21 and human CYP3A4. CYP3A21 may be an equivalent of CYP3A4 in New World monkeys, consistent with the phylogenetic relationship between these genes. The marmoset, therefore, appears to be a suitable in vivo model to study CYP3A4 function and regulation.
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Affiliation(s)
- S C Koehler
- Klinische Chemie, Uni-Klinikum Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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Braun F, Schöcklmann H, Ziegler E, Kunzendorf U, Armstrong VW, Renders L. Increased Mycophenolic Acid Exposure in Stable Kidney Transplant Recipients on Tacrolimus as Compared With Those on Sirolimus: Implications for Pharmacokinetics. Clin Pharmacol Ther 2009; 86:411-5. [DOI: 10.1038/clpt.2009.129] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Schlumbohm C, Bramlage C, Strutz F, Armstrong VW, Oellerich M, Fuchs E. Predictive value of maternal bodyweight, postnatal weight gain and prenatal dexamethasone overexposure for the development of obesity in adult marmoset monkeys. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-990427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Heller T, van Gelder T, Budde K, de Fijter JW, Kuypers D, Arns W, Schmidt J, Rostaing L, Powis SH, Claesson K, Macphee IAM, Pohanka E, Engelmayer J, Brandhorst G, Oellerich M, Armstrong VW. Plasma concentrations of mycophenolic acid acyl glucuronide are not associated with diarrhea in renal transplant recipients. Am J Transplant 2007; 7:1822-31. [PMID: 17532750 DOI: 10.1111/j.1600-6143.2007.01859.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aim of this study was to determine whether plasma concentrations of the acyl (AcMPAG) and phenolic (MPAG) glucuronide metabolites of mycophenolic acid (MPA) were related to diarrhoea in renal transplant patients on mycophenolate mofetil (MMF) with cyclosporine (CsA) or tacrolimus (TCL). Blood samples (0, 30, 120 min) were taken at days 3, 10, week 4, months 3, 6 and 12 for determination of MPA, MPAG and AcMPAG. MPA-AUC was estimated using validated algorithms. Two hour AUCs were calculated for MPAG and AcMPAG. Immunosuppressive therapy consisted of CsA/MMF (n= 110) and of TCL/MMF (n= 180). In 70/290 (24%) patients 86 episodes of diarrhoea were recorded during 12 months. Significantly more patients on TCL (31.1%) suffered from diarrhea compared to CsA (12.7%). MMF dose, MPA-AUC and the 2 h AUCs of MPAG and AcMPAG did not differ between patients with and without diarrhoea. Plasma AcMPAG and MPAG concentrations were substantially higher in patients on CsA compared with TCL, while MPA-AUC was lower in the former group. These data support the concept that CsA inhibits the biliary excretion of MPAG and AcMPAG, thereby potentially reducing the risk of intestinal injury through enterohepatic recycling of MPA and its metabolites.
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Affiliation(s)
- T Heller
- Department of Clinical Chemistry, Georg-August-Universität Göttingen, Germany
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Mielck F, Ziarkowski A, Hanekop G, Armstrong VW, Hilgers R, Weyland A, Quintel M, Sonntag H. Cerebral inflammatory response during and after cardiac surgery. Eur J Anaesthesiol 2005; 22:347-52. [PMID: 15918382 DOI: 10.1017/s0265021505000591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE Neurological dysfunction is a common problem after cardiac surgery with cardiopulmonary bypass (CPB). Cerebral ischaemia associated with the use of CPB may result in a release of neuronal-ischaemic markers and a subsequent cerebral inflammatory response which may additionally release inflammatory cytokines. In order to locate the origin and to quantify the release of neuronal-ischaemic markers and cytokines we investigated arterial-cerebral venous concentration gradients during and after CPB in a clinical setting. METHODS In twenty-five patients scheduled for coronary artery bypass grafting surgery we measured the plasma concentration of neuron-specific enolase, S-100beta protein as well as interleukins (IL) IL-6, IL-8 and IL-10 from arterial and cerebral venous blood samples prior to surgery (baseline), during hypothermic CPB at 32 degrees C, after termination of bypass, as well as 2, 4 and 6 h after admission to the intensive care unit. RESULTS Arterial-cerebral venous concentration gradients of neuron-specific enolase, S-100beta, IL-6, IL-8 and IL-10 were neither detectable during nor after CPB. Compared to the baseline period, S-100beta and neuron-specific enolase significantly increased during hypothermic CPB. After termination of CPB, neuronal-ischaemic markers as well as cytokines were increased and remained elevated during the investigated time course without reaching baseline values. CONCLUSIONS Although we found an overall increase in plasma concentrations of neuronal-ischaemic markers, IL-6, IL-8 and IL-10 during and after CPB, arterial-cerebral venous gradients were not detectable for any of these parameters. Our results suggest that the increase of investigated parameters associated with the use of CPB are not primarily caused by a cerebral inflammatory response but rather reflect a release from other sources in the systemic circulation.
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Affiliation(s)
- F Mielck
- University of Göttingen, Department of Anaesthesiology, Göttingen, Germany.
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Braun JP, Schroeder T, Buehner S, Dohmen P, Moshirzadeh M, Grosse J, Streit F, Schlaefke A, Armstrong VW, Oellerich M, Lochs H, Konertz W, Kox WJ, Spies C. Splanchnic oxygen transport, hepatic function and gastrointestinal barrier after normothermic cardiopulmonary bypass. Acta Anaesthesiol Scand 2004; 48:697-703. [PMID: 15196101 DOI: 10.1111/j.1399-6576.2004.00392.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The effect of non-pulsatile, normothermic cardiopulmonary-bypass (CPB) on the splanchnic blood-flow and oxygen-transport, the hepatic function and the gastrointestinal barrier were observed in a prospective observational study in 31 adults undergoing cardiac valve replacement surgery. METHODS The splanchnic (i.e. hepatic) blood-flow (HBF) was measured by the constant infusion of indocyanine-green (ICG) using a hepatic-venous catheter. Liver function was examined by calculation of lactate uptake, ICG extraction and the monoethylglycinexylidide (MEGX) test. A day before and after surgery the gastrioduodenal and intestinal permeability was measured by determination of sucrose and lactulose/mannitol excretion. RESULTS Splanchnic blood flow and oxygen delivery did not decrease during and after surgery while splanchnic oxygen consumption (P < 0.0125) and arterial lactate concentrations increased. The splanchnic lactate uptake paralleled the lactate concentration. After but not during CPB an increase of systemic oxygen consumption was observed. The MEGX test values decreased on the first day after surgery. The ICG extraction was attenuated during the operation. The gastroduodenal and the intestinal permeability increased significantly postoperatively (P < 0.002, respectively, P < 0.001). There was no correlation between these findings and the duration of CPB. There was a significant correlation of the intestinal permeability but not of the gastroduodenal permeability between the prior and after surgery values (P < 0.001). CONCLUSION Increased oxygen consumption during CPB may indicate an inflammatory reaction due to the pump beginning in the splanchnic area or a redistribution of the splanchinc blood flow during the CPB. Normothermic CPB does not lead to a significant or prolonged reduction of liver function. Normothermic CPB causes an increase of gastrointestinal permeability. The intestinal barrier function prior to surgery was accountable for the degree of loss of intestinal barrier function following surgery.
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Affiliation(s)
- J P Braun
- Department of Anesthesiology and Intensive Care, University Hospital Charité, Humboldt University, Berlin, Germany.
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Weber LT, Shipkova M, Armstrong VW, Mehls O, Oellerich M, Tönshoff B. C2 monitoring and absorption profiling of cyclosporine for optimization of immunosuppressive therapy in pediatric renal transplant recipients. Transplant Proc 2003; 35:2128-30. [PMID: 14529863 DOI: 10.1016/s0041-1345(03)00743-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- L T Weber
- University Children's Hospital Heidelberg, Division of Paediatric Nephrology, Heidelberg, Germany
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Schettler V, Kühn W, Kleinoeder T, Armstrong VW, Oellerich M, Müller GA, Wieland E. No acute impact of haemodialysis treatment on free radical scavenging enzyme gene expression in white blood cells. J Intern Med 2003; 253:201-7. [PMID: 12542561 DOI: 10.1046/j.1365-2796.2003.01088.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Oxidative stress has been implicated in the side-effects caused by haemodialysis (HD) treatment. DESIGN In the present study we have investigated whether gene expression of the enzymatic defence system provided by cellular glutathione peroxidase (GPx-1), phospholipid glutathione peroxidase (GPx-4), glutathione reductase (GSSG-R), glutathione synthethase (GSH-S), Cu/Zn-superoxide dismutase (SOD-1) and catalase (CAT) is affected by HD. The GPx-1, GPx-4, GSSG-R, GSH-S, SOD-1 and CAT mRNA were determined in white blood cells by quantitative reverse transcriptase-polymerase chain reaction with the LightCycler instrument and transcription elongation factor-2 as reference gene at the start (SD) and immediately after (ED) dialysis treatment (n = 36). In a subgroup (n = 10), messenger RNA (mRNA) expression was determined hourly during a 5 h HD. RESULTS The expression of GPx-1, GPx-4, GSSG-R, GSH-S, SOD-1 and CAT mRNA was not affected by a single HD treatment. All mRNAs were significantly (P < 0.05) increased in HD patients [median (16. percentiles (perc.); 84. perc.)]: GPx-1: 2.18 (0.89; 3.23); GPx-4: 0.41 (0.26; 0.74); GSSG-R: 0.04 (0.02; 0.10); GSH-S: 0.04 (0.02; 0.08); SOD-1: 0.32 (0.20; 0.62); CAT: 0.12 (0.06; 0.18) when compared with healthy blood donors (GPx-1: 0.91 (0.60; 1.44); GPx-4: 0.27 (0.16; 0.43); GSSG-R: 0.02 (0.01; 0.02); GSH-S: 0.02 (0.02; 0.04); SOD-1: 0.15 (0.10; 0.18); CAT: 0.07 (0.04; 0.16). CONCLUSIONS These results show that the HD procedure does not acutely affect the antioxidant defence system on the gene level but suggest that the chronic stress caused by uraemia and/or HD may cause gene induction of the enzymatic defence system.
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Affiliation(s)
- V Schettler
- Department of Nephrology and Rheumatology, Division of Internal Medicine, Georg-August-University, Robert-Koch-Strasse 40, Göttingen, Germany.
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Kiehl MG, Schäfer-Eckart K, Kröger M, Bornhäuser M, Basara N, Blau IW, Kienast J, Fauser AA, Ehninger G, Armstrong VW, Shipkova M. Mycophenolate mofetil for the prophylaxis of acute graft-versus-host disease in stem cell transplant recipients. Transplant Proc 2002; 34:2922-4. [PMID: 12431658 DOI: 10.1016/s0041-1345(02)03489-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- M G Kiehl
- Department of Hematology/Oncology, BMT Unit, Idar-Oberstein, Germany.
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Schettler V, Wieland E, Armstrong VW, Kleinoeder T, Grunewald RW, Müller GA. First steps toward the establishment of a German low-density lipoprotein-apheresis registry: recommendations for the indication and for quality management. Ther Apher 2002; 6:381-3. [PMID: 12423533 DOI: 10.1046/j.1526-0968.2002.00426.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
New recommendations for the indication of treatment with selective extracorporeal plasma therapy low-density lipoprotein apheresis (LDL-apheresis) in the prevention of coronary heart disease are urgently needed. The following points are the first results of the ongoing discussion process for indications for LDL-apheresis in Germany: all patients with homozygous familial hypercholesterolemia with functional or genetically determined lack or dysfunction of LDL receptors and plasma LDL cholesterol levels >13.0 mmol/L (>500 mg/dL); patients with coronary heart disease (CHD) documented by clinical symptoms and imaging procedures in which over a period of at least 3 months the plasma LDL cholesterol levels cannot be lowered below 3.3 mmol/L (130 mg/dL) by a generally accepted, maximal drug-induced and documented therapy in combination with a cholesterol-lowering diet; and patients with progression of their CHD documented by clinical symptoms and imaging procedures and repeated plasma Lp(a) levels >60 mg/dL, even if the plasma LDL cholesterol levels are lower than 3.3 mmol/L (130 mg/dL). Respective goals for LDL cholesterol concentrations for high-risk patients have been recently defined by various international societies. To safely put into practice the recommendations for LDL-apheresis previously mentioned, standardized treatment guidelines for LDL-apheresis need to be established in Germany that should be supervised by an appropriate registry.
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Affiliation(s)
- V Schettler
- Department of Nephrology and Rheumatology, Georg-August-University of Göttingen, Göttingen, Germany.
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Grupp C, Hemprich U, John H, Braun F, Lorf T, Armstrong VW, Ringe B, Müller GA. Lectin staining for urine cytologic monitoring after kidney transplantation. Transplant Proc 2002; 34:1751-2. [PMID: 12176562 DOI: 10.1016/s0041-1345(02)03053-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- C Grupp
- Abteilung Nephrologie and Rheumatologie, Georg-August-Universität Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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Armstrong VW. Principles and Practice of Monitoring Immunosuppressive Drugs. Grundsatze und Praxis beim Monitoring von Immunsuppressiva. ACTA ACUST UNITED AC 2002. [DOI: 10.1046/j.1439-0477.2002.02004.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Shipkova M, Armstrong VW, Kuypers D, Perner F, Fabrizi V, Holzer H, Wieland E, Oellerich M. Effect of cyclosporine withdrawal on mycophenolic acid pharmacokinetics in kidney transplant recipients with deteriorating renal function: preliminary report. Ther Drug Monit 2001; 23:717-21. [PMID: 11802109 DOI: 10.1097/00007691-200112000-00020] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mycophenolic acid (MPA) concentrations are lower in transplant recipients receiving mycophenolate mofetil (MMF) and cyclosporine compared with MMF with tacrolimus. It is not clear whether this is due to an effect of cyclosporin or tacrolimus on MPA pharmacokinetics. To study this effect, kidney transplant recipients with deteriorating renal function (n = 5) receiving cyclosporin and steroids were given mycophenolate mofetil over 4 weeks during a run-in phase (1 g/d in week 1, 1.5 g/d in week 2, 2 g/d starting from week 3). From week 5 the cyclosporin dose was reduced, and it was completely withdrawn at week 10. Creatinine, MPA, and MPA glucuronide metabolites (MPAG, AcMPAG) were determined before (week 4) and after (week 11 and week 32) cyclosporin was withdrawn. Cyclosporin withdrawal was associated with increased MPA areas under the curve (AUCs) and predose concentrations in four of the five patients. In contrast, MPAG and AcMPAG AUCs as well as predose MPAG concentrations significantly decreased. Six months after cyclosporin withdrawal, MPA AUC and predose values tended to return to initial values, whereas metabolite concentrations remained low. Cyclosporin discontinuation caused an acute increase in MPA exposure and a concomitant reduction in metabolite concentrations. The results are consistent with the hypothesis that cyclosporin attenuates the enterohepatic recirculation of MPAG/MPA.
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Affiliation(s)
- M Shipkova
- Department of Clinical Chemistry, Georg-August-University Göttingen, Göttingen, Germany.
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Wiltfang J, Schenk-Daprá B, Stiens G, Bleich S, Bandelow B, Müller P, Niedmann PD, Armstrong VW, Rüther E. Clozapine-associated elevation of plasma cholinesterase. Eur Arch Psychiatry Clin Neurosci 2001; 251:269-71. [PMID: 11881840 DOI: 10.1007/pl00007544] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The goal of this study was to identify adverse effects of the atypical neuroleptic clozapine on liver function and lipid metabolism. METHODS Data which included serum levels of clozapine and its hepatic metabolite N-desmethyl clozapine were collected from medical records of patients treated with clozapine and controls. RESULTS We identified a clozapine-associated marked elevation of plasma cholinesterase (ChE) with unchanged levels of AST, ALT or g-GT. ChE was correlated to the serum level of clozapine and even closer to N-desmethyl clozapine. For the total patient group we observed significant correlations of ChE with the body-mass index and body weight. However, clozapine-treated patients and controls did not differ with regard to body-mass index, triglycerides, and cholesterol. CONCLUSION We report for the first time a clozapine-associated and dose-dependent elevation of plasma ChE, which may be related to clozapine-associated effects on hepatic lipid metabolism or ChE enzyme induction.
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Affiliation(s)
- J Wiltfang
- Department of Psychiatry and Psychotherapy, Göttingen, Germany.
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Braun F, Armstrong VW, Lorf T, Canelo R, Arndt C, Oellerich M, Ringe B. Comparison of trough level and C(2) cyclosporine blood concentration monitoring in outpatient kidney transplant recipients. Transplant Proc 2001; 33:3108-9. [PMID: 11750336 DOI: 10.1016/s0041-1345(01)02325-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- F Braun
- Klinik für Transplantationschirurgie, Georg-August-Universität, Göttingen, Germany
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Braun F, Kassuhn M, Laabs S, Streit F, Armstrong VW, Oellerich M, Ringe B. Intestinal biotransformation of cyclosporine A in an extracorporeal pig intestine perfusion model. Transplant Proc 2001; 33:3154-5. [PMID: 11750354 DOI: 10.1016/s0041-1345(01)02343-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- F Braun
- Klinik für Transplantationschirurgie, Georg-August-Universität, Göttingen, Germany
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Streit F, Niedmann PD, Shipkova M, Armstrong VW, Oellerich M. Rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of monoethylglycinexylidide. Clin Chem 2001; 47:1853-6. [PMID: 11568101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- F Streit
- Department of Clinical Chemistry, George-August University Goettingen, 37075 Goettingen, Germany
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Braun F, Schütz E, Peters B, Talaulicar R, Grupp C, Undre N, Schäfer A, Armstrong VW, Oellerich M, Ringe B. Pharmacokinetics of tacrolimus primary immunosuppression in kidney transplant recipients. Transplant Proc 2001; 33:2127-8. [PMID: 11377473 DOI: 10.1016/s0041-1345(01)01970-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- F Braun
- Klinik für Transplantationschirugie, Georg-August-Universität, Göttingen, Germany
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Stoyanova E, Tesch A, Armstrong VW, Wieland E. Enzymatically degraded low density lipoproteins are more potent inducers of egr-1 mRNA than oxidized or native low density lipoproteins. Clin Biochem 2001; 34:483-90. [PMID: 11676978 DOI: 10.1016/s0009-9120(01)00258-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The transcription factor early growth response gene-1 (Egr-1) may contribute to atherosclerosis by inducing genes that mediate inflammation and thrombosis. Egr-1 mRNA is highly expressed in human atherosclerotic lesions. Enzymatic modification transforms LDL into atherogenic molecules (E-LDL) which are also present in atherosclerotic lesions. We have investigated whether E-LDL induces egr-1 mRNA in human monocytes. DESIGN AND METHODS Mono-Mac-6 cells were incubated with E-LDL, oxidized (Ox-LDL) and native LDL (N-LDL). Egr-1 mRNA expression was followed by quantitative RT-PCR. RESULTS E-LDL (25 microg cholesterol/mL) induced egr-1 mRNA maximally within 1 h and were 2.3 and 3.6 fold (p < 0.05) more effective than Ox-LDL or N-LDL. At a concentration of 10 microg/mL cholesterol, E-LDL were twofold less effective. CONCLUSIONS These results show that E-LDL are potent inducers of egr-1 mRNA and may therefore represent a link between lipoproteins trapped in the subendothelium and enhanced expression of egr-1 in human atherosclerotic lesions.
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Affiliation(s)
- E Stoyanova
- Abteilung Klinische Chemie, Georg-August-Universität Göttingen, Göttingen, Germany
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Shipkova M, Armstrong VW, Kiehl MG, Niedmann PD, Schütz E, Oellerich M, Wieland E. Quantification of mycophenolic acid in plasma samples collected during and immediately after intravenous administration of mycophenolate mofetil. Clin Chem 2001; 47:1485-8. [PMID: 11468247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- M Shipkova
- Department of Clinical Chemistry, Georg-August-University Göttingen, D-37075 Göttingen, Germany. maria
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von Ahsen N, Richter M, Grupp C, Ringe B, Oellerich M, Armstrong VW. No influence of the MDR-1 C3435T polymorphism or a CYP3A4 promoter polymorphism (CYP3A4-V allele) on dose-adjusted cyclosporin A trough concentrations or rejection incidence in stable renal transplant recipients. Clin Chem 2001; 47:1048-52. [PMID: 11375290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
BACKGROUND A substantial proportion of the variability in the absorption and clearance of cyclosporin A (CsA) after oral administration has been attributed to variability in liver cytochrome P-450 3A4 (CYP3A4) activity and intestinal P-glycoprotein (P-gp) concentration. A polymorphism in the CYP3A4 promoter region, termed "variant" allele CYP3A4-V, was postulated to be associated with altered CYP3A4 enzyme activity. A polymorphism in exon 26 (C3435T) of the multidrug resistance-1 (MDR-1) gene was correlated with intestinal expression and in vivo activity of P-gp. METHODS We investigated the occurrence of both polymorphisms in 124 stable Caucasian renal transplant recipients (>6 months after transplantation) on CsA as the primary immunosuppressant. Real-time, rapid-cycle PCR methods were developed and used for genotyping. RESULTS The estimated allele frequencies for the MDR-1 C3435T allele (54%) and the CYP3A4-V allele (4.8%) were similar to those reported for Caucasian populations. No significant differences were found for the CsA doses needed to maintain similar CsA trough concentrations in patients with and without the CYP3A4-V allele or in patients with different MDR-1 C3435T genotypes. Furthermore, neither of the polymorphisms investigated was associated with renal function as assessed by creatinine plasma concentration or, in a retrospective analysis, the incidence of acute rejection. CONCLUSIONS These findings suggest that the MDR-1 C3435T mutation and the CYP3A4-V variant are not major determinants of CsA efficacy in renal transplant recipients.
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Affiliation(s)
- N von Ahsen
- Department of Clinical Chemistry, Georg-August-University, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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Oellerich M, Armstrong VW. Prodrug metabolites: implications for therapeutic drug monitoring. Clin Chem 2001; 47:805-6. [PMID: 11325880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Abstract
The dynamic liver function test based on the hepatic conversion of lidocaine to monoethylglycinexylidide (MEGX) can complement established static liver function tests if prognostic information is of particular interest. Because of its ease of use and rapid turnaround, the MEGX test has found widespread application for realtime assessment of hepatic function in transplantation, critical care medicine, and various experimental models. Lidocaine is metabolized primarily by the liver cytochrome P450 system through sequential oxidative N-dealkylation, the major initial metabolite in humans being MEGX. Because of the relatively high extraction ratio of lidocaine, this liver function test depends not only on hepatic metabolic capacity but also on hepatic blood flow. For the determination of MEGX in serum, an immunoassay based on the fluorescence polarization immunoassay technique high-performance liquid chromatography and gas liquid chromatography methods have been described. Whereas high-performance liquid chromatography and gas liquid chromatography are specific for MEGX, the fluorescence polarization immunoassay also cross-reacts with 3-OH-MEGX. Although this is not a problem in humans, some species, such as the rat, produce significant amounts of this metabolite. The findings of most studies published so far suggest that the MEGX test is a useful tool that can improve our decision-making process with respect to the selection of transplant candidates. Patients with a MEGX 15- or 30-minute test value <10 microg/L have a particularly poor 1-year survival rate. Serial monitoring of liver graft recipients early after transplantation with the MEGX test may initially alert the clinician to a major change in liver function; if used with other tests, such as serum hyaluronic acid concentrations, it may become more discriminatory. In critically ill patients, several studies have shown that an initially rapid decrease in MEGX test values is associated with an enhanced risk for the development of multiple organ dysfunction syndrome and a poor outcome. Further, this decrease appears to be associated with an enhanced systemic inflammatory response. The MEGX test has potential for investigating the pathogenesis of multiple organ dysfunction syndrome with regard to early hepatic functional impairment in critically ill patients after polytrauma or sepsis.
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Affiliation(s)
- M Oellerich
- Department of Clinical Chemistry, Georg-August University, Göttingen, Germany.
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Shipkova M, Strassburg CP, Braun F, Streit F, Gröne HJ, Armstrong VW, Tukey RH, Oellerich M, Wieland E. Glucuronide and glucoside conjugation of mycophenolic acid by human liver, kidney and intestinal microsomes. Br J Pharmacol 2001; 132:1027-34. [PMID: 11226133 PMCID: PMC1572641 DOI: 10.1038/sj.bjp.0703898] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Mycophenolic acid (MPA) is primarily metabolized to a phenolic glucuronide (MPAG) as well as to two further minor metabolites: an acyl glucuronide (AcMPAG) and a phenolic glucoside (MPAG1s). This study presents investigations of the formation of these metabolites by human liver (HLM), kidney (HKM), and intestinal (HIM) microsomes, as well as by recombinant UDP-glucuronosyltransferases. HLM (n=5), HKM (n=6), HIM (n=5) and recombinant UGTs were incubated in the presence of either UDP-glucuronic acid or UDP-glucose and various concentrations of MPA. Metabolite formation was followed by h.p.l.c. All microsomes investigated formed both MPAG and AcMPAG. Whereas the efficiency of MPAG formation was greater with HKM compared to HLM, AcMPAG formation was greater with HLM than HKM. HIM showed the lowest glucuronidation efficiency and the greatest interindividual variation. The capacity for MPAGls formation was highest in HKM, while no glucoside was detected with HIM. HKM produced a second metabolite when incubated with MPA and UDP-glucose, which was labile to alkaline treatment. Mass spectrometry of this metabolite in the negative ion mode revealed a molecular ion of m/z 481 compatible with an acyl glucoside conjugate of MPA. All recombinant UGTs investigated were able to glucuronidate MPA with K:(M:) values ranging from 115.3 to 275.7 microM l(-1) and V(max) values between 29 and 106 pM min(-1) mg protein(-1). Even though the liver is the most important site of MPA glucuronidation, extrahepatic tissues particularly the kidney may play a significant role in the overall biotransformation of MPA in man. Only kidney microsomes formed a putative acyl glucoside of MPA.
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Affiliation(s)
- M Shipkova
- Abteilung für Klinische Chemie, Georg-August-Universität, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany.
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Wieland E, Shipkova M, Schütz E, Braun F, Niedmann P, Armstrong VW, Ringe B, Svinarov DA, Oellerich M. Preliminary report on the effect of xenoperfusion with human blood on cyclosporin A metabolism and cytochrome-P-4503A4-mRNA expression in a pig liver perfusion model. Clin Biochem 2001; 34:53-7. [PMID: 11239516 DOI: 10.1016/s0009-9120(00)00203-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Little is known about the effect of ischemia/reperfusion with xenogenic blood on function and gene expression of CYP3A4, the enzyme largely responsible for the metabolism of the immunosuppressants Cyclosporin A (CsA) and Tacrolimus. DESIGN AND METHODS In a pig liver perfusion model, we have compared the effect of perfusion (3 h) after 20 h cold storage, with either pig or human blood on CsA metabolism and CYP3A4-mRNA expression. mCYP3A4-mRNA was quantified by RT-PCR, CsA and its major metabolites AM1, AM9, AM4N by RP-HPLC. IL-6 served as inflammation marker, GLDH and ALT to estimate tissue damage. RESULTS Inflammatory response and tissue damage were more extensive during xenoperfusion. CYP3A4 expression decreased similarly during xenogenic and allogenic perfusion. CsA conversion to its metabolites was also comparable during xeno- and alloperfusion. CONCLUSION There is no evidence that during the early reperfusion period pig liver CYP3A4 is severely affected if the organ is xenoperfused with human blood in comparison with alloperfusion.
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Affiliation(s)
- E Wieland
- Abteilung Klinische Chemie, Georg-August-Universität Göttingen, Robert-Koch-Street 40, D-37075, Göttingen, Germany.
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Shipkova M, Wieland E, Schütz E, Wiese C, Niedmann PD, Oellerich M, Armstrong VW. The acyl glucuronide metabolite of mycophenolic acid inhibits the proliferation of human mononuclear leukocytes. Transplant Proc 2001; 33:1080-1. [PMID: 11267199 DOI: 10.1016/s0041-1345(00)02424-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- M Shipkova
- Georg-August Universität Göttingen, Zentrum Innere Medizin, Abt. Klinische Chemie, Göttingen, Germany
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Abstract
The calcineurin inhibitors cyclosporine and tacrolimus form the cornerstones of most immunosuppression protocols. Because of their variable pharmacokinetics, and their narrow therapeutic indices, post-transplant immunosuppressive drug monitoring is an essential part of patient care to minimize the risks of toxicity or acute rejection. Furthermore, a reduction in the rate of acute rejection has been shown to result in a lower rate of graft loss due to chronic rejection. The introduction of the microemulsion formulation of cyclosporine with its more consistent bioavailability has renewed interest in the use of alternative sampling strategies to the trough cyclosporine concentration. Both pharmacokinetic and pharmacodynamic considerations support the concept that determination of cyclosporine during the absorption phase (0-4 h) might offer a better prediction of cyclosporine immunosuppressive efficacy. Initial investigations suggest that monitoring a 2-h postdose concentration C(2) may provide a more efficacious alternative to trough monitoring for optimizing therapy with Neoral. Tacrolimus has a 10- to 100-fold greater in vitro immunosuppressive activity compared with cyclosporine. Consistent with its greater potency, therapeutic whole blood trough concentrations for tacrolimus are around 20-fold lower than the corresponding cyclosporine concentrations. The correlation between toxicity and tacrolimus trough concentrations appears to be stronger than that for acute rejection. The results from a concentration-ranging trial in primary kidney-transplantation and liver-transplantation trials all found a significant relationship between toxicity and tacrolimus trough levels. Azathioprine is converted in vivo to 6-mercaptopurine, which is subsequently metabolized to the pharmacologically active 6-thioguanine nucleotides. The latter are also responsible for the cytotoxic side effects. Reliance on blood counts to monitor azathioprine therapy can be misleading, and they do not provide information on immunosuppresive efficacy. More pertinent information can be obtained through the measurement of thiopurine S-methyltransferase activity and the quantification of intracellular 6-thioguanine nucleotides concentrations in red blood cells. Prospective studies have demonstrated the clinical utility of determining 6-thioguanine nucleotides to individualise immunosuppressive therapy with azathioprine not only in the field of transplantation, but also in inflammatory bowel disease.
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Affiliation(s)
- V W Armstrong
- Abteilung Klinische Chemie, Zentrum Innere Medizin, Georg-August-Universität Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.
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Affiliation(s)
- V W Armstrong
- Department of Clinical Chemistry, Georg-August University, Göttingen, Germany
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Igonin AA, Armstrong VW, Shipkova M, Kukes VG, Oellerich M. The monoethylglycinexylidide (MEGX) test as a marker of hepatic dysfunction in septic patients with pneumonia. Clin Chem Lab Med 2000; 38:1125-8. [PMID: 11156341 DOI: 10.1515/cclm.2000.169] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this study was to monitor hepatic function in patients with pneumonia meeting the sepsis criteria of the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) and to determine if hepatic dysfunction is related to the systemic inflammatory response. Twenty patients were recruited. The monoethylglycinexylidide (MEGX) test was carried out on days 1-10 after admittance to the intensive care unit. Blood samples for determination of serum concentrations of hyaluronic acid, C-reactive protein (CRP), interleukin (IL)-6, IL-8, IL-10 and conventional liver function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, albumin) were also drawn. Patients were classified into two groups according to illness severity estimated by the simplified acute physiology score (SAPS II) on the day of admission. Patients in group I (n=10) had a SAPS II probability of mortality >3% while those in group II (n=10) had a SAPS II < 3%. The MEGX level over the first five days was significantly lower in group I than in group II (p<0.0001). Significant inverse correlations during the first 5 days were observed between the MEGX 30 min test results and IL-6, CRP and SAPS II and more modest correlations with hyaluronic acid (p=0.0025) and IL-10 (p=0.021). The conventional liver function tests did not differ between the two groups and were mostly within the respective reference ranges. We conclude that the MEGX test is a sensitive marker of liver dysfunction early in sepsis and that low MEGX values are associated with an enhanced inflammatory response.
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Affiliation(s)
- A A Igonin
- Department of Clinical Pharmacology, I.M. Sechenov Medical Academy, Moscow, Russia.
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Kiehl MG, Shipkova M, Basara N, Blau IW, Schütz E, Armstrong VW, Oellerich M, Fauser AA. Mycophenolate mofetil in stem cell transplant patients in relation to plasma level of active metabolite. Clin Biochem 2000; 33:203-8. [PMID: 10913519 DOI: 10.1016/s0009-9120(00)00053-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To investigate mycophenolate mofetil (MMF) plasma levels and impact on acute graft versus host disease (aGvHD) after stem cell transplantation (SCT). METHODS SCT patients (n = 14) with aGvHD (>/= II) receiving MMF (1-3 g/d) in addition to cyclosporine, prednisolone, and methotrexate for aGvHD prophylaxis were investigated. Plasma levels of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) were determined by high-performance liquid chromatography. RESULTS Overall median steady state pre-dose plasma MPA concentration was 0.47 mg/L and increased within 75 min after administration to 1.64 mg/L. In comparison to patients with skin aGvHD, patients with gut aGvHD had lower MPA concentrations, both pre-dose (p = 0.16) and after 75 min, (p = 0.02). All 7 patients with skin aGvHD but only 2 patients with gut aGvHD responded to MMF. Overall, the pre-dose plasma MPA concentration was significantly (p = 0.007) greater in responders (n = 9) than in non-responders (n = 5). CONCLUSION MMF seems to be an effective treatment for aGvHD in SCT patients particular in those patients without gut involvement.
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Affiliation(s)
- M G Kiehl
- Department of BMT and Hematology/Oncology, Bone Marrow Transplant Unit, Dr. Ottmar-Kohler Str. 2, 55743, Idar-Oberstein, Germany.
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Wieland E, Shipkova M, Schellhaas U, Schütz E, Niedmann PD, Armstrong VW, Oellerich M. Induction of cytokine release by the acyl glucuronide of mycophenolic acid: a link to side effects? Clin Biochem 2000; 33:107-13. [PMID: 10751588 DOI: 10.1016/s0009-9120(99)00101-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVES We have identified an acyl glucuronide (M-2) of the immunosuppressant mycophenolic acid (MPA). Acyl glucuronides have toxic potential and may contribute to drug toxicity. Whether acyl glucuronides are able to induce release of proinflammatory cytokines is unknown. Gastrointestinal disturbances have been observed during MPA therapy and may involve an inflammatory reaction. This study investigated whether M-2 can induce IL-6 and TNF-alpha release as well as gene expression of these cytokines in leukocytes. DESIGN AND METHODS M-2 was produced by incubation of MPA with human liver microsomes. Human mononuclear leukocytes were incubated in the presence of M-2. Concentrations of IL-6 and TNF-alpha were measured by ELISA. Expression of mRNA was determined by quantitative RT-PCR. RESULTS Incubation of 3 x 10(6) cells with M-2 resulted in a time and dose dependent release of cytokines, whereas MPA or its phenolic glucuronide MPAG were without effect. Cytokine liberation depended on mRNA induction. Response to M-2 showed much inter individual variability (30-fold for IL-6, 3-fold for TNF-alpha). CONCLUSIONS If M-2 promotes release of cytokines in vivo, these may mediate some of the toxic actions of MPA.
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Affiliation(s)
- E Wieland
- Abteilung Klinische Chemie, Georg-August-Universität Göttingen, Göttingen, Germany.
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Shipkova M, Schütz E, Armstrong VW, Niedmann PD, Oellerich M, Wieland E. Determination of the acyl glucuronide metabolite of mycophenolic acid in human plasma by HPLC and Emit. Clin Chem 2000; 46:365-72. [PMID: 10702523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
BACKGROUND The acyl glucuronide (AcMPAG) of mycophenolic acid (MPA) has been found to possess pharmacologic and potentially proinflammatory activity in vitro. To establish its pharmacologic and toxicologic relevance in vivo, a reversed-phase HPLC method was modified to simultaneously determine MPA, the phenolic MPA-glucuronide (7-O-MPAG), and AcMPAG. In addition, cross-reactivity of AcMPAG in the Emit assay for MPA was investigated. METHODS The procedure used simple sample preparation, separation with a Zorbax Eclipse-XDB-C8 column, and gradient elution. AcMPAG was quantified as 7-O-MPAG-equivalents. RESULTS The assay was linear up to 50 mg/L for MPA, 250 mg/L for 7-O-MPAG, and 10 mg/L for AcMPAG (r >0.999). Detection limits were 0.01, 0.03, and 0.04 mg/L for MPA, 7-O-MPAG, and AcMPAG, respectively. The recoveries were 99-103% for MPA, 95-103% for 7-O-MPAG, and 104-107% for AcMPAG. The within-day imprecision was <5.0% for MPA (0.2-25 mg/L), <4.4% for 7-O-MPAG (10-250 mg/L), and < or =14% for AcMPAG (0.1-5 mg/L). The between-day imprecision was <6.2%, <4.5%, and < or =14% for MPA, 7-O-MPAG, and AcMPAG, respectively. When isolated from microsomes, purified AcMPAG (1-10 mg/L) revealed a concentration-dependent cross-reactivity in an Emit assay for the determination of MPA ranging from 135% to 185%. This is in accordance with the bias between HPLC and Emit calculated in 270 samples from kidney transplant recipients receiving mycophenolate mofetil therapy, which was greater (median, 151.2%) than the respective AcMPAG concentrations determined by HPLC. AcMPAG was found to undergo hydrolysis when samples were stored up to 24 h at room temperature or up to 30 days at 4 degrees C or -20 degrees C. Acidified samples (pH 2.5) were stable up to 30 days at -20 degrees C. CONCLUSIONS The HPLC and Emit methods for AcMPAG described here may allow investigation of its relevance for the immunosuppression and side effects associated with mycophenolate mofetil therapy.
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Affiliation(s)
- M Shipkova
- Abteilung Klinische Chemie, Zentrum Innere Medizin, Georg-August-Universität Göttingen, Germany.
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Oellerich M, Shipkova M, Schütz E, Wieland E, Weber L, Tönshoff B, Armstrong VW. Pharmacokinetic and metabolic investigations of mycophenolic acid in pediatric patients after renal transplantation: implications for therapeutic drug monitoring. German Study Group on Mycophenolate Mofetil Therapy in Pediatric Renal Transplant Recipients. Ther Drug Monit 2000; 22:20-6. [PMID: 10688252 DOI: 10.1097/00007691-200002000-00004] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The need for mycophenolic acid (MPA) monitoring is still under discussion. Key issues for the PK/PD relationships of this drug are: the role of metabolites, the usefulness of AUC versus predose levels, and the need to monitor the free concentration of MPA (f-MPA). Recent advances have revealed that, in addition to 7-O-MPAG, three additional MPA metabolites are present in the plasma of transplant recipients. One of these metabolites (M-2), identified as an acyl glucuronide of MPA, was found to inhibit IMPDH-II in vitro. This active metabolite was also found to cross-react in the Emit assay for MPA. In an ongoing multicenter study, the authors are evaluating the relevance of monitoring total (t-MPA) and free mycophenolic acid (f-MPA) in pediatric renal transplant recipients. As in adults, a time-dependent increase of t-MPA-AUC(0-12h) within the first 3 months posttransplant (35 versus 64 mg x h/L, [corrected] 3 weeks versus 3 months respectively; daily dosage: 0.6 g/m2 bid) was seen. Receiver operating characteristics curve analyses were used to test the ability of predose levels or AUC(0-12h) to discriminate between cases with no complications and those with acute rejection, adverse events (severe infections, leukopenia), or gastrointestinal disorders observed during the early posttransplant course. In agreement with observations in adults, a significant (p = 0.001) association was observed between AUC(0-12h) and acute rejection. A t-MPA-AUC(0-12h) of approximately 30-60 mg x h/L [corrected], as determined by HPLC, seems to be a reasonable target for the early posttransplant period. It remains to be elucidated whether regular predose level monitoring may be of more practical value. A higher incidence of rejection was observed at predose MPA concentrations < or = 1 mg/L, as measured by HPLC. In contrast to t-MPA, f-MPA-AUC(0-12h) was significantly related to severe infections and leukopenia. The risk for severe adverse events was increased at f-MPA- AUC(0-12h) values > or =600 microg x h/L [corrected]. On the basis of these data and the observed variability in the pharmacokinetics of MPA, the development of monitoring strategies for this drug appears to be promising.
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Affiliation(s)
- M Oellerich
- Department of Clinical Chemistry, Georg-August-University Gottingen, Germany
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von Ahsen N, Oellerich M, Armstrong VW, Schütz E. Application of a thermodynamic nearest-neighbor model to estimate nucleic acid stability and optimize probe design: prediction of melting points of multiple mutations of apolipoprotein B-3500 and factor V with a hybridization probe genotyping assay on the LightCycler. Clin Chem 1999; 45:2094-101. [PMID: 10585340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND PCR-based mutation detection is prone to methodological errors, e.g., in restriction length fragment polymorphism (RFLP) and allele-specific amplification (ASA), false PCR results may occur because of technical faults or atypical new mutations. METHODS We investigated the ability of a genotyping assay based on hybridization of labeled oligonucleotides to detect and discriminate known and as yet unknown mutations in the factor V and apolipoprotein B-100 genes. Expected melting points were calculated using a nearest-neighbor model for nucleic acid duplex stability and compared with experimental findings derived from LightCycler melting curves. A method for genotyping the apolipoprotein B-100 G10699A and C10698T mutations is presented. RESULTS All mismatches tested for in the probed sequence could be detected with a single probe. The measured melting points were in good agreement with their values predicted using the nearest-neighbor model (r = 0.96; y = 0.98x + 1.18; S(y|x) = 0.96; n = 24). CONCLUSIONS This procedure not only allows the identification of the mutation of interest but also enables the discrimination from other potential mutations in the vicinity of the former. The nearest-neighbor model is valid for hybridization probe assays on the LightCycler and should be of general value in setting up such assays. We have shown for two clinically relevant genotyping examples that the LightCycler mutation detection system has superior discriminatory performance compared with conventional RFLP or ASA PCR-based methods for molecular diagnostic purposes. With this method, in every hybridization probe assay, all mutations under a properly designed probe should be detectable, but they will not necessarily be discriminated from each other in all cases.
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Affiliation(s)
- N von Ahsen
- Department of Clinical Chemistry, Georg-August-University, Robert-Koch-Strasse 40, 37075 Goettingen, Germany.
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Weber LT, Lamersdorf T, Shipkova M, Niedmann PD, Wiesel M, Zimmerhackl LB, Staskewitz A, Schütz E, Mehls O, Oellerich M, Armstrong VW, Tönshoff B. Area under the plasma concentration-time curve for total, but not for free, mycophenolic acid increases in the stable phase after renal transplantation: a longitudinal study in pediatric patients. German Study Group on Mycophenolate Mofetil Therapy in Pediatric Renal Transplant Recipients. Ther Drug Monit 1999; 21:498-506. [PMID: 10519445 DOI: 10.1097/00007691-199910000-00002] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Mycophenolate mofetil, an ester prodrug of the immunosuppressant mycophenolic acid (MPA), is widely used for maintenance immunosuppressive therapy in pediatric renal transplant recipients. However, little is known about the pharmacokinetics of MPA in this patient population in the stable transplant phase, and dosage guidelines are preliminary. The authors therefore compared the pharmacokinetics of MPA, free MPA, and the renal metabolite MPA glucuronide (MPAG) in the initial (sampling at 1 and 3 weeks) and stable phases (sampling at 3 and 6 months) posttransplant in 17 children (age, 12.0 +/- 0.77 years; range, 5.9 to 15.8 years), receiving the currently recommended dose of 600 mg MMF/m2 body surface area (BSA) twice a day. Plasma concentrations of MPA and MPAG were measured by reverse phase HPLC. Because MPA is extensively bound to serum albumin and only the free drug is presumed to be pharmacologically active, the authors also analyzed the MPA free fraction by HPLC after separation by ultrafiltration. The intraindividual variability of the area under the concentration-time curves (AUC0-12) of MPA throughout the 12-hour dosing interval was high in the immediate posttransplant period, but declined in the stable phase, whereas the interindividual variability remained unchanged. The median MPA-AUC0-12 values increased 2-fold from 32.4 (range, 13.9 to 57.0) mg x h/L at 3 weeks to 65.1 (range, 32.6 to 114) mg x h/L at 3 months after transplantation, whereas the median AUC0-12 values of free MPA did not significantly change over time. This discrepancy can be attributed to a 35% decline of the MPA free fraction from 1.4% in the initial phase posttransplant to 0.9% (p < 0.01) in the stable phase. In conclusion, pediatric renal transplant recipients given a fixed MMF dose exhibit a 2-fold increase of the AUC0-12 of total MPA in the stable phase posttransplant and a 35% decrease of the MPA free fraction, whereas the AUC0-12 of free MPA remains unchanged over time. Because the latter pharmacokinetic variable is theoretically best predictive of the clinical immunosuppressive efficacy of MMF, these findings may have consequences for the dosing recommendations of MMF in renal transplant recipients.
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Affiliation(s)
- L T Weber
- Division of Pediatric Nephrology, University Children's Hospital Heidelberg, Germany
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Weber LT, Schütz E, Lamersdorf T, Shipkova M, Niedmann PD, Oellerich M, Zimmerhackl LB, Staskewitz A, Mehls O, Armstrong VW, Tönshoff B. Pharmacokinetics of mycophenolic acid (MPA) and free MPA in paediatric renal transplant recipients--a multicentre study. The German Study Group on Mycophenolate Mofetil (MMF) Therapy. Nephrol Dial Transplant 1999; 14 Suppl 4:33-4. [PMID: 10463208 DOI: 10.1093/ndt/14.suppl_4.33] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- L T Weber
- University Children's Hospitals Heidelberg, Germany
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Weber LT, Schütz E, Lamersdorf T, Shipkova M, Niedmann PD, Oellerich M, Zimmerhackl LB, Staskewitz A, Mehls O, Armstrong VW, Tönshoff B. Therapeutic drug monitoring of total and free mycophenolic acid (MPA) and limited sampling strategy for determination of MPA-AUC in paediatric renal transplant recipients. The German Study Group on Mycophenolate Mofetil (MMF) Therapy. Nephrol Dial Transplant 1999; 14 Suppl 4:34-5. [PMID: 10463209 DOI: 10.1093/ndt/14.suppl_4.34] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- L T Weber
- University Children's Hospitals Heidelberg, Germany
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von Ahsen N, Schütz E, Armstrong VW, Oellerich M. Rapid detection of prothrombotic mutations of prothrombin (G20210A), factor V (G1691A), and methylenetetrahydrofolate reductase (C677T) by real-time fluorescence PCR with the LightCycler. Clin Chem 1999; 45:694-6. [PMID: 10222362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- N von Ahsen
- Department of Clinical Chemistry, Georg-August-University, Robert Koch Strasse 40, 37075 Goettingen, Germany
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El Desoky ES, Ahmed AM, Nafeh MA, Ahmed HA, Schütz E, Armstrong VW, Oellerich M. Assessment of liver function by the MEGX test in patients with schistosomiasis and cirrhosis. Clin Biochem 1999; 32:207-12. [PMID: 10383082 DOI: 10.1016/s0009-9120(99)00007-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The aim of this study was to determine the effect of schistosomiasis infection on hepatic function in Egyptian patients with posthepatitic cirrhosis. DESIGN AND METHODS Hepatic function, was assessed in 66 Egyptian patients, with (n = 30) and without (n = 36) schistosomal liver fibrosis due to Schistosoma mansoni and in 20 healthy controls, using the monoethylglycinexylidide (MEGX) test. Serum MEGX concentrations were measured before and 5, 15, 30, 60, 120, and 180 min after a lidocaine bolus. The sero-prevalence of antibodies to hepatitis C was also determined in the patients. RESULTS MEGX test results were significantly lower in patients than in controls at all time points. MEGX test results declined with advancing Child Class. Receiver operating characteristic (ROC) curve analysis revealed the following areas under the ROC curves for discrimination of Child Class C from Child Classes A/B: 30 min, 0.762; 60 min, 0.743; 120 min, 0.731; 15 min, 0.728; 180 min, 0.728; 5 min, 0.602. Schistosomiasis infection had no influence on MEGX test results when cirrhotic patients with (Schisto+) and without (Schisto-) schistosomiasis were compared. While the prevalence of the hepatitis B surface antigen was only 16.7% (Schisto-) and 26.7% (Schisto+), there was an extremely high sero-prevalence of antibodies to hepatitis C (HCV) in both groups: 88.9% (Schisto-) and 73.3% (Schisto+). CONCLUSIONS The association of schistosomal liver fibrosis with cirrhosis does not additionally influence MEGX formation. In addition, HCV rather than schistosomiasis infection must be considered as a major cause for the progressive liver disease in these patients.
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Affiliation(s)
- E S El Desoky
- Department of Pharmacology, Faculty of Medicine, Assuit University, Egypt
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Shipkova M, Armstrong VW, Wieland E, Niedmann PD, Schütz E, Brenner-Weiss G, Voihsel M, Braun F, Oellerich M. Identification of glucoside and carboxyl-linked glucuronide conjugates of mycophenolic acid in plasma of transplant recipients treated with mycophenolate mofetil. Br J Pharmacol 1999; 126:1075-82. [PMID: 10204993 PMCID: PMC1565876 DOI: 10.1038/sj.bjp.0702399] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1. Mycophenolic acid (MPA), is primarily metabolized in the liver to 7-O-MPA-beta-glucuronide (MPAG). Using RP-h.p.l.c. we observed three further MPA metabolites, M-1, M-2, M-3, in plasma of transplant recipients on MMF therapy. To obtain information on the structure and source of these metabolites: (A) h.p.l.c. fractions containing either metabolite or MPA were collected and analysed by tandem mass spectrometry; (B) the metabolism of MPA was studied in human liver microsomes in the presence of UDP-glucuronic acid, UDP-glucose or NADPH; (C) hydrolysis of metabolites was investigated using beta-glucosidase, beta-glucuronidase or NaOH; (D) cross-reactivity of each metabolite was tested in an immunoassay for MPA (EMIT). 2. Mass spectrometry of M-1, M-2, MPA and MPAG in the negative ion mode revealed molecular ions of m/z 481, m/z 495, m/z 319 and m/z 495 respectively. 3. Incubation of microsomes with MPA and UDP-glucose produced M-1, with MPA and UDP-glucuronic acid MPAG and M-2 were formed, while with MPA and NADPH, M-3 was observed. 4. Beta-Glucosidase hydrolysed M-1 completely. Beta-Glucuronidase treatment led to a complete disappearance of MPAG whereas the amount of M-2 was reduced by approximately 30%. Only M-2 was labile to alkaline treatment. 5. M-2 and MPA but not M-1 and MPAG cross-reacted in the EMIT assay. 6. These results suggest that: (i) M-1 is the 7-OH glucose conjugate of MPA; (ii) M-2 is the acyl glucuronide conjugate of MPA; (iii) M-3 is derived from the hepatic CYP450 system.
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Affiliation(s)
- M Shipkova
- Abteilung Klinische Chemie, George-August-Universität Göttingen, Germany.
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Schütz E, Shipkova M, Armstrong VW, Wieland E, Oellerich M. Identification of a pharmacologically active metabolite of mycophenolic acid in plasma of transplant recipients treated with mycophenolate mofetil. Clin Chem 1999; 45:419-22. [PMID: 10053049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Affiliation(s)
- E Schütz
- Abteilung Klinische Chemie, Zentrum Innere Medizin, Georg-August-Universität, Robert Koch Strasse 40, D-37075 Göttingen, Germany.
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Shipkova M, Schütz E, Armstrong VW, Niedmann PD, Wieland E, Oellerich M. Overestimation of mycophenolic acid by EMIT correlates with MPA metabolite. Transplant Proc 1999; 31:1135-7. [PMID: 10083508 DOI: 10.1016/s0041-1345(98)01936-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- M Shipkova
- Abteilung Klinische Chemie, Georg-August-Universität, Göttingen, Germany
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Shipkova M, Armstrong VW, Schneider T, Niedmann PD, Schütz E, Wieland E, Oellerich M. Stability of mycophenolic acid and mycophenolic acid glucuronide in human plasma. Clin Chem 1999; 45:127-9. [PMID: 9895349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Affiliation(s)
- M Shipkova
- Abteilung Klinische Chemie, Georg-August-Universität Göttingen, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany
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Braun F, Canelo R, Schütz E, Shipkora M, Lorf T, Hanack U, Niedmann D, Armstrong VW, Oellerich M, Ringe B. How to handle mycophenolate mofetil in combination with tacrolimus? Transplant Proc 1998; 30:4094-5. [PMID: 9865309 DOI: 10.1016/s0041-1345(98)01354-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- F Braun
- Klinik für Transplantationschirurgie, George-August-Universität, Göttingen, Germany
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Armstrong VW, Schuetz E, Zhang Q, Groothuisen S, Scholz C, Shipkova M, Aboleneen H, Oellerich M. Modified pentamer formation assay for measurement of tacrolimus and its active metabolites: comparison with liquid chromatography-tandem mass spectrometry and microparticle enzyme-linked immunoassay (MEIA-II). Clin Chem 1998; 44:2516-23. [PMID: 9836720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A modified pentamer formation assay (PFA) for quantification of tacrolimus and active metabolites after extraction from whole blood is described. The lower limit of detection was 2 microg/L. Intraassay precision (CV) was 5.7-13.7%, and the interassay CV was 6. 1-14.9%. Tacrolimus trough concentrations in 104 whole blood specimens from liver and kidney transplant recipients were compared with results from HPLC-tandem mass spectrometry (LC/MS/MS) and microparticle enzyme immunoassay (MEIA-II). Data were analyzed by difference plots and are presented as median (95% confidence intervals) of the method differences. MEIA-II results were on average 2.00 microg/L (range, -0.08 to 5.17 microg/L) higher than LC/MS/MS, whereas PFA results were only 1.07 microg/L (range, -2.62 to 5.33 microg/L) higher. Of 104 specimens tested, 25 displayed differences >/=3 microg/L between MEIA-II and PFA: median difference, 4.65 microg/L (range, 3.01-8.79 microg/L). The corresponding median difference between PFA and LC/MS/MS was -0.91 microg/L (range, -4.11 to 0.85 microg/L), and the difference between MEIA-II and LC/MS/MS was 3.67 microg/L (range, 1.88-6.34 microg/L), suggesting the presence of inactive metabolites that caused a positive bias in the immunoassay. In contrast, similar median differences were observed for the remaining 79 specimens: MEIA-II minus LC/MS/MS, 1.78 microg/L (range, -0.45 to 4.11 microg/L); PFA minus LC/MS/MS, 1.90 microg/L (range, -1.70 to 5.50 microg/L). Active tacrolimus metabolites may have contributed to the higher apparent tacrolimus concentrations in these specimens.
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Affiliation(s)
- V W Armstrong
- 1 Abteilung Klinische Chemie, Georg-August-Universitaet Goettingen, D-37075 Goettingen, Germany.
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