Armstrong, Victor William

[["dc.bibliographiccitation.firstpage","20"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Therapeutic Drug Monitoring"],["dc.bibliographiccitation.lastpage","26"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Oellerich, M."],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Schutz, Ekkehard"],["dc.contributor.author","Wieland, Eberhard"],["dc.contributor.author","Weber, Lutz T."],["dc.contributor.author","Tonshoff, B."],["dc.contributor.author","Armstrong, Victor William"],["dc.date.accessioned","2018-11-07T10:55:24Z"],["dc.date.available","2018-11-07T10:55:24Z"],["dc.date.issued","2000"],["dc.description.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-dependant increase of t-MPA-AUC(0-12h) within the first 3 months posttransplant (35 versus 64 mg x L/h, 3 weeks versus 3 months respectively; daily dosage: 0.6 g/m(2) 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 L/h, 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 less than or equal to 1 mg/L, as measured by HPLC. In contrast to t-MPA, f-MPA-AUC(0-12h) was significantly related to seven infections and leukopenia. The risk for severe adverse events was increased at f-MPA- AUC(0-12h) values greater than or equal to 600 mu g x Uh. 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 he promising."],["dc.identifier.doi","10.1097/00007691-200002000-00004"],["dc.identifier.isi","000085149700004"],["dc.identifier.pmid","10688252"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49780"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.relation.issn","0163-4356"],["dc.title","Pharmacokinetic and metabolic investigations of mycophenolic acid in pediatric patients after renal transplantation: Implications for therapeutic drug monitoring"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","664A"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Blood"],["dc.bibliographiccitation.lastpage","665A"],["dc.bibliographiccitation.volume","98"],["dc.contributor.author","Kiehl, M. G."],["dc.contributor.author","Schaefer-Eckart, K."],["dc.contributor.author","Kienast, J."],["dc.contributor.author","Jenke, A."],["dc.contributor.author","Wandt, Hannes"],["dc.contributor.author","Blau, Igor W."],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Silling, Gerda"],["dc.contributor.author","Basara, N."],["dc.contributor.author","Fauser, A. A."],["dc.contributor.author","Bornhaeuser, Martin"],["dc.date.accessioned","2018-11-07T11:24:06Z"],["dc.date.available","2018-11-07T11:24:06Z"],["dc.date.issued","2001"],["dc.identifier.isi","000172134102799"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/56328"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Hematology"],["dc.publisher.place","Washington"],["dc.relation.issn","0006-4971"],["dc.title","Randomized multicenter prospective clinical trial on the efficacy of mycophenolate mofetil in comparison to methotrexate for the prophylaxis of acute GvHD in stem cell transplant recipients."],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1551"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Clinical Chemistry"],["dc.bibliographiccitation.lastpage","1552"],["dc.bibliographiccitation.volume","49"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Wieland, Eberhard"],["dc.contributor.author","Oellerich, M."],["dc.date.accessioned","2018-11-07T10:36:24Z"],["dc.date.available","2018-11-07T10:36:24Z"],["dc.date.issued","2003"],["dc.identifier.isi","000184896200028"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45314"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Assoc Clinical Chemistry"],["dc.relation.issn","0009-9147"],["dc.title","Commentary on: Differences in nucleotide hydrolysis contribute to the differences between erythrocyte 6-thioguanine nucleotide concentrations determined by two widely used methods - Response"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.subtype","letter_note"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Therapeutic Drug Monitoring"],["dc.bibliographiccitation.volume","25"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Voland, A."],["dc.contributor.author","Grone, H. J."],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Oellerich, M."],["dc.contributor.author","Wieland, Eberhard"],["dc.date.accessioned","2018-11-07T10:37:34Z"],["dc.date.available","2018-11-07T10:37:34Z"],["dc.date.issued","2003"],["dc.format.extent","537"],["dc.identifier.isi","000184445500220"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45598"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.publisher.place","Philadelphia"],["dc.relation.conference","8th International Congress of Therapeutic Drug Monitoring and Clinical Toxicology"],["dc.relation.eventlocation","BASEL, SWITZERLAND"],["dc.relation.issn","0163-4356"],["dc.title","Relationship between plasma concentrations of mycophenolic acid (MPA) and its acyl glucuronide (AcMPAG) and intestinal damage in Wistar rats treated with mycophenolate mofetil (MMF)"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","123"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Therapeutic Drug Monitoring"],["dc.bibliographiccitation.lastpage","131"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Barten, Markus J."],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Bartsch, P."],["dc.contributor.author","Dhein, S."],["dc.contributor.author","Streit, Frank"],["dc.contributor.author","Tarnok, A."],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Mohr, F. W."],["dc.contributor.author","Oellerich, M."],["dc.contributor.author","Gummert, J. E."],["dc.date.accessioned","2018-11-07T11:14:21Z"],["dc.date.available","2018-11-07T11:14:21Z"],["dc.date.issued","2005"],["dc.description.abstract","The effect of mycophenolic acid (MPA) in combination with either cyclosporine (CsA) or tacrolimus (TRL) on whole-blood lymphocyte function was assessed in vitro as well as in vivo. For the in vitro studies, rat whole blood was incubated with different concentrations of MPA together with CsA or TRL. In vivo, rats (n = 6 per group) were orally treated with 2.5 or 5 ing/kg of mycophenolate mofetil (MMF), either alone or in combination with 5 mg/kg CsA or 4 mg/kg TRL. Blood was obtained before and at different times after dosing. For both in vitro and in vivo studies, mitogen-stimulated whole blood was analyzed by flow cytometry to determine inhibition of expression of lymphocyte proliferation (proliferating cell nuclear antigen, PCNA) and T-cell activation (eg, CD25). Plasma MPA concentrations were measured by HPLC, and whole-blood CsA and TRL concentrations were quantified using LC-MS/MS. In vitro, low concentrations of 250 and 500 nM MPA acted additively with CsA and overadditively with TRL to suppress lymphocyte function, whereas higher MPA concentrations (1000 nM) in these combinations did not further increase inhibition compared with monotherapy with CsA or TRL alone. In vivo, the MPA AUC(O-24) showed a dose-dependent increase. CsA and TRL AUC(O-24) were not influenced by the MMF dose. Combination therapy increased inhibition of lymphocyte function compared with MMF monotherapy with a pronounced effect on PCNA compared with CD25. Significant differences between 2.5 and 5 mg/kg MMF in the combination groups were observed at 2 or 6 hours after dosing because of the maximal inhibitory effect oil PCNA and CD25 expression (P < 0.05, ANOVA), However, in combination with TRL no different effects on the inhibition of CD25 expression were found between the 2 MMF doses. These novel data indicate that measurement of pharmacodynamic parameters of lymphocyte function in whole blood may help to monitor drug combination therapy and provide a rationale for drug reduction to minimize toxicity without compromising efficacy."],["dc.identifier.doi","10.1097/01.ftd.0000146874.11480.8a"],["dc.identifier.isi","000228115500003"],["dc.identifier.pmid","15795640"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54104"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.relation.issn","0163-4356"],["dc.title","Mycophenolic acid interaction with cyclosporine and tacrolimus in vitro and in vivo - Evaluation of additive effects on rat blood lymphocyte function"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","107"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Clinical Biochemistry"],["dc.bibliographiccitation.lastpage","113"],["dc.bibliographiccitation.volume","33"],["dc.contributor.author","Wieland, Eberhard"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Schellhaas, Ulrike"],["dc.contributor.author","Schütz, Ekkehard"],["dc.contributor.author","Niedmann, Paul Dieter"],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Oellerich, Michael"],["dc.date.accessioned","2021-06-01T10:50:05Z"],["dc.date.available","2021-06-01T10:50:05Z"],["dc.date.issued","2000"],["dc.description.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. Copyright (C) 2000 The Canadian Society of Clinical Chemists."],["dc.identifier.doi","10.1016/S0009-9120(99)00101-0"],["dc.identifier.isi","000086461900005"],["dc.identifier.pmid","10751588"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/86520"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0009-9120"],["dc.title","Induction of cytokine release by the acyl glucuronide of mycophenolic acid: A link to side effects?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","53"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Clinical Biochemistry"],["dc.bibliographiccitation.lastpage","57"],["dc.bibliographiccitation.volume","34"],["dc.contributor.author","Wieland, Eberhard"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Schütz, Ekkehard"],["dc.contributor.author","Braun, Felix"],["dc.contributor.author","Niedmann, Paul-Dieter"],["dc.contributor.author","Armstrong, Victor W."],["dc.contributor.author","Ringe, Burckhardt"],["dc.contributor.author","Svinarov, Dobrin A."],["dc.contributor.author","Oellerich, Michael"],["dc.date.accessioned","2021-06-01T10:50:04Z"],["dc.date.available","2021-06-01T10:50:04Z"],["dc.date.issued","2001"],["dc.description.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. CYP3A4-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. (C) 2001 The Canadian Society of Clinical Chemists. All rights reserved."],["dc.identifier.doi","10.1016/S0009-9120(00)00203-4"],["dc.identifier.isi","000169234600010"],["dc.identifier.pmid","11239516"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/86518"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.publisher.place","Oxford"],["dc.relation.conference","Analytical Conference 2000"],["dc.relation.eventlocation","MUNICH, GERMANY"],["dc.relation.issn","0009-9120"],["dc.title","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"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","ChemInform"],["dc.bibliographiccitation.volume","36"],["dc.contributor.author","Armstrong, Victor W."],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","von Ahsen, Nicolas"],["dc.contributor.author","Oellerich, Michael"],["dc.date.accessioned","2021-12-08T12:29:19Z"],["dc.date.available","2021-12-08T12:29:19Z"],["dc.date.issued","2005"],["dc.identifier.doi","10.1002/chin.200502276"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/96028"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-476"],["dc.relation.eissn","1522-2667"],["dc.relation.issn","0931-7597"],["dc.rights.uri","http://doi.wiley.com/10.1002/tdm_license_1.1"],["dc.title","Analytic Aspects of Monitoring Therapy with Thiopurine Medications"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","367A"],["dc.bibliographiccitation.journal","Journal of the American Society of Nephrology"],["dc.bibliographiccitation.lastpage","368A"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Kuypers, DRJ"],["dc.contributor.author","Vanrenterghem, Y."],["dc.contributor.author","Squifflet, J. P."],["dc.contributor.author","Mourad, M."],["dc.contributor.author","Abramowicz, D."],["dc.contributor.author","Oellerich, H."],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Daems, J."],["dc.date.accessioned","2018-11-07T10:07:05Z"],["dc.date.available","2018-11-07T10:07:05Z"],["dc.date.issued","2002"],["dc.identifier.isi","000177757501813"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39217"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.publisher.place","Philadelphia"],["dc.relation.issn","1046-6673"],["dc.title","Results of a 12 month multicenter trial investigating the kinetics of MPA and MPA-metabolites and the efficacy and side-effect profile of mycophenolate mofetil in renal transplant patients in view of MPA and MPA-metabolites."],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","438"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Therapeutic Drug Monitoring"],["dc.bibliographiccitation.lastpage","443"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Wigger, M."],["dc.contributor.author","Armstrong, Victor William"],["dc.contributor.author","Shipkova, Maria"],["dc.contributor.author","Wacke, R."],["dc.contributor.author","Nizze, H."],["dc.contributor.author","Streit, Frank"],["dc.contributor.author","von Ahsen, Nicolas"],["dc.contributor.author","Muscheites, J."],["dc.contributor.author","Glasenapp, S."],["dc.contributor.author","Stolpe, H. J."],["dc.contributor.author","Oellerich, M."],["dc.date.accessioned","2018-11-07T10:29:47Z"],["dc.date.available","2018-11-07T10:29:47Z"],["dc.date.issued","2002"],["dc.description.abstract","A juvenile, female renal transplant recipient suffered two acute rejection episodes: the first on posttransplant day 31 while taking cyclosporine, prednisone, and mycophenolate mofetil (MMF); and the second on posttransplant clay 67, when she was taking tacrolimus, prednisone, and MMF. Dosage of MMF was initially started at 2 g/d (corresponding to 600 mg MMF/m(2) twice daily) but was reduced to 250 mg/d to 500 mg/d after severe diarrhea and a paralytic ileus on posttransplant day 16. During therapy with tacrolimus, prednisone, and MMF, predose plasma mycophenolic acid (MPA) concentrations varied from 1.1 mg/L to 8.2 mg/L (median 3.0 mg/L). On posttransplant day 91, a 12-hour pharmacokinetic profile was obtained. The concentrations of MPA and its metabolites were determined with a validated high-performance liquid chromatography (HPLC) procedure. After oral MMIF (250 mg) administration, the MPA concentration showed an atypical decline front a predose concentration of 6.0 mg/L to a value of 3.8 mg/L at 75 minutes postdose, and 3.4 mg/L at 6 hours postdose, before returning to 6.0 mg/L after 12 hours. The 12-hour area under the concentration-time curve (AUC) values for MPA and its major metabolite the phenolic glucuronide MPAG were 55.1 mg.h/L and 800 mg.h/L, respectively. An unusually high concentration (12-h AUC, 165 mg.h/L) of the phenolic glucose conjugate of MPA was found. The apparent renal clearance of MPAG was only 2.2 mL/min. Her creatinine clearance was 30 mL/min. MPAG clearances have been reported to range from approximately. 5.5 m:/min to 35 mL/min at a creatinine clearance of approximately 30 mL/min in renal transplant recipients. The authors' findings suggest that conjugation and clearance of MPA through the kidney is strongly impaired in this patient. The relatively high preclose MPA concentrations could result from an enhanced enterohepatic circulation of MPA and its metabolites."],["dc.identifier.doi","10.1097/00007691-200206000-00019"],["dc.identifier.isi","000175866900019"],["dc.identifier.pmid","12021639"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43715"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Lippincott Williams & Wilkins"],["dc.relation.issn","0163-4356"],["dc.title","Atypical pharmacokinetics and metabolism of mycophenolic acid in a young kidney transplant recipient with impaired renal function"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]