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van Laar T, Bayulkem K. 1.001 PD: Motor and non-motor fluctuations. Parkinsonism Relat Disord 2007. [DOI: 10.1016/s1353-8020(08)70352-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Smeding HMM, Speelman JD, Koning-Haanstra M, Schuurman PR, Nijssen P, van Laar T, Schmand B. Neuropsychological effects of bilateral STN stimulation in Parkinson disease: a controlled study. Neurology 2006; 66:1830-6. [PMID: 16801645 DOI: 10.1212/01.wnl.0000234881.77830.66] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate the cognitive and behavioral effects of bilateral subthalamic nucleus (STN) stimulation in patients with Parkinson disease (PD). METHODS The authors included 103 patients; 99 patients were evaluated 6 months after surgery. A control group of 39 patients with PD was formed and 36 patients were evaluated 6 months later. At baseline and at follow-up we administered neuropsychological tests of language, memory, visuospatial function, mental speed, and executive functions. A depression rating scale, a quality of life scale, self and proxy ratings of memory and dysexecutive symptoms, and a neuropsychiatric interview were also administered. RESULTS Six months after surgery, the STN group showed a larger decline than the control group on measures of verbal fluency, color naming, selective attention, and verbal memory. Moreover, the STN group showed a decrease in positive affect, and an increase in emotional lability and cognitive complaints. On the other hand, the STN group showed an increase in quality of life and a slight decrease in depressive symptoms. Nine percent of the STN patients had psychiatric complications (vs 3% of controls). CONCLUSIONS Bilateral subthalamic nucleus stimulation has an adverse effect on executive functions with implications for daily life of the patients and their relatives.
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Gort EH, Groot AJ, Derks van de Ven TLP, van der Groep P, Verlaan I, van Laar T, van Diest PJ, van der Wall E, Shvarts A. Hypoxia-inducible factor-1alpha expression requires PI 3-kinase activity and correlates with Akt1 phosphorylation in invasive breast carcinomas. Oncogene 2006; 25:6123-7. [PMID: 16682946 DOI: 10.1038/sj.onc.1209643] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hypoxia-inducible factor-1 alpha (HIF-1alpha) is the regulatory subunit of the heterodimeric transcription factor HIF-1 and the key factor in cellular response to low oxygen tension. Expression of HIF-1alpha protein is associated with poor patient survival and therapy resistance in many types of solid tumors. Insight into HIF-1alpha regulation in solid tumors is important for therapeutic strategies. In this study, we determined the pathophysiological relevance of HIF-1alpha regulation by the oncogenic phosphatidylinositol 3'-kinase (PI 3-kinase)/Akt signaling pathway. We modeled the physiology of hypoxic tumor regions by culturing carcinoma cells under low oxygen tension in the absence of serum. We observed that hypoxic induction of HIF-1alpha protein was decreased by serum deprivation. Overexpression of dominant-active Akt1 restored HIF-1alpha expression, whereas inhibition of PI 3-kinase activity reduced hypoxic HIF-1alpha protein levels to a similar extent as serum deprivation. Immunohistochemical analysis of 95 human breast cancers revealed that lack of Akt1 phosphorylation correlates with low HIF-1alpha levels. To our knowledge, this is the first reported comparison between HIF-1alpha expression and Akt phosphorylation in human carcinomas. We conclude that Akt activity is physiologically relevant for HIF-1alpha expression in breast cancer. This implies that HIF-1alpha function might be therapeutically targeted by inhibition of the PI 3-kinase/Akt pathway.
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van Laar T. III.P1 Visual hallucinations in Parkinson's Disease; the relationship with visual processing and attention. Parkinsonism Relat Disord 2006. [DOI: 10.1016/s1353-8020(07)70099-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Portman AT, van Laar T, Staal MJ, Rutgers AWF, Journee HL, Leenders KL. Chronic stimulation of the subthalamic nucleus increases daily on-time without dyskinesia in advanced Parkinson's disease. Parkinsonism Relat Disord 2006; 12:143-8. [PMID: 16460986 DOI: 10.1016/j.parkreldis.2005.10.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 10/18/2005] [Accepted: 10/25/2005] [Indexed: 11/21/2022]
Abstract
We assessed the efficacy of chronic stimulation of the subthalamic nucleus (STN-DBS) in 20 patients with Parkinson's disease (PD) by means of clinical assessments and patient diaries 12 months after surgery. STN-DBS reduced the UPDRS part III off-medication score by 33%, and successively improved complete daily on-time without dyskinesia at 12 months significantly. In conclusion, our study demonstrates the efficacy of chronic STN-DBS on motor features in a selected population of advanced PD patients. In addition to clinical assessments, patients' diaries serve as an essential tool to evaluate the functional motor status after STN-DBS.
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Hilker R, Portman AT, Voges J, Staal MJ, Burghaus L, van Laar T, Koulousakis A, Maguire RP, Pruim J, de Jong BM, Herholz K, Sturm V, Heiss WD, Leenders KL. Disease progression continues in patients with advanced Parkinson's disease and effective subthalamic nucleus stimulation. J Neurol Neurosurg Psychiatry 2005; 76:1217-21. [PMID: 16107354 PMCID: PMC1739814 DOI: 10.1136/jnnp.2004.057893] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Glutamate mediated excitotoxicity of the hyperactive subthalamic nucleus (STN) has been reported to contribute to nigral degeneration in Parkinson's disease (PD). Deep brain stimulation of the STN (STN DBS), in its role as a highly effective treatment of severe PD motor complications, has been thought to inhibit STN hyperactivity and therefore decrease progression of PD. METHODS In a prospective two centre study, disease progression was determined by means of serial (18)F-fluorodopa (F-dopa) positron emission tomography (PET) in 30 patients with successful STN DBS over the first 16 (SD 6) months after surgery. RESULTS Depending on the method of PET data analysis used in the two centres, annual progression rates relative to baseline were 9.5-12.4% in the caudate and 10.7-12.9% in the putamen. CONCLUSIONS This functional imaging study is the first to demonstrate a continuous decline of dopaminergic function in patients with advanced PD under clinically effective bilateral STN stimulation. The rates of progression in patients with STN DBS were within the range of previously reported data from longitudinal imaging studies in PD. Therefore this study could not confirm the neuroprotective properties of DBS in the STN target.
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Li GL, de Vries JJ, van Steeg TJ, van den Bussche H, Maas HJ, Reeuwijk HJEM, Danhof M, Bouwstra JA, van Laar T. Transdermal iontophoretic delivery of apomorphine in patients improved by surfactant formulation pretreatment. J Control Release 2005; 101:199-208. [PMID: 15588905 DOI: 10.1016/j.jconrel.2004.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Accepted: 09/16/2004] [Indexed: 11/28/2022]
Abstract
The objective of the present study is to evaluate the efficacy and the safety of transdermal iontophoretic delivery of R-apomorphine, a potent dopamine agonist, in combination with surfactant pretreatment in patients with advanced Parkinson's disease. Iontophoresis patches were applied in 16 patients for 3.5 h, with 0.5 h of passive delivery followed by 3 h of current application at a current density of 250 microA/cm2. Eight of these patients were treated with a surfactant formulation prior to iontophoresis. The pharmacokinetics, pharmacodynamic effects, systemic and local side effects of R-apomorphine were assessed. The plasma concentration vs. time profiles upon iontophoresis of R-apomorphine were described successfully by a novel pharmacokinetic model. The model suggests that only 1.9% of the dose that has been released from the patch accumulated in the skin. The patients treated with the surfactant formulations showed a statistically significant increase of bioavailability (from 10.6+/-0.8% to 13.2+/-1.4%) and of the steady state input rate (from 75.3+/-6.6 to 98.3+/-12.1 nmol/cm2 h) compared to the control patients (iontophoresis without absorption enhancers). In five out of eight patients in the study group and in three out of eight patients in the control group, clinical improvement was observed.
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Hilker R, Portman AT, Voges J, Staal MJ, Burghaus L, van Laar T, Koulousakis A, Maguire RP, Pruim J, Herholz K, de Jong BM, Sturm V, Heiss WD, Leenders KL. Erkrankungsprogression bei Patienten mit idiopathischem Parkinson-Syndrom und STN-Stimulation – Eine 18-Fluorodopa-PET-Verlaufsstudie. AKTUELLE NEUROLOGIE 2005. [DOI: 10.1055/s-2005-866691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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van Laar T, Schouten T, van der Eb AJ, Terleth C. Induction of the SAPK activator MIG-6 by the alkylating agent methyl methanesulfonate. Mol Carcinog 2001; 31:63-7. [PMID: 11429782 DOI: 10.1002/mc.1040] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The alkylating agent methylmethanesulfonate (MMS) activates the c-jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) and the p38 mitogen-activated protein kinase (p38MAPK) pathways via different mechanisms of action. Activation of p38MAPK by MMS involves the pp125 focal adhesion kinase-related tyrosine kinase RAFTK and the MAPK kinase 3. The way in which MMS can activate JNK/SAPK has not been elucidated. Here we describe the identification by differential display of human mitogen-activated gene-6 (MIG-6) as a novel MMS-inducible gene. Induction of MIG-6 by MMS was found in human diploid skin fibroblasts and in simian virus 40-transformed skin fibroblasts, indicating that the enhanced expression of MIG-6 after MMS-treatment did not require p53. The signal leading to activation of MIG-6 appeared to be independent of DNA damage. High MIG-6 expression was found in the liver, lung, and placenta. MIG-6 is an adapter protein that binds to the activated form of cdc42Hs and to 14-3-3 proteins, thereby activating JNK/SAPKs. Our results suggest that activation of JNK/SAPKs by MMS may involve the induction of MIG-6.
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van Laar T, van der Eb AJ, Terleth C. Mif1: a missing link between the unfolded protein response pathway and ER-associated protein degradation? Curr Protein Pept Sci 2001; 2:169-90. [PMID: 12370023 DOI: 10.2174/1389203013381189] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eukaryotic cells have three different mechanisms to deal with the accumulation of unfolded proteins in the endoplasmic reticulum: (1) In cells in which unfolded polypeptides accumulate, translation initiation is inhibited to prevent further accumulation of unfolded proteins. (2) Expression of proteins involved in polypeptide folding is strongly enhanced by a process called the Unfolded Protein Response (UPR). (3) Proteins missing the proper tertiary structure are degraded by the ER-Associated protein Degradation (ERAD) mechanism. Recent studies in S. cerevisiae have shown that the processes of UPR and ERAD are functionally linked to each other. Cells lacking a functional ERAD show a constitutive activation of UPR. In addition, many of the components of ERAD are under the direct transcriptional control of UPR. Finally, while neither UPR nor ERAD are essential for cell viability, deletion of both pathways results in severe growth impairment. UPR and ERAD are conserved between yeast and mammalian cells. One of the components of mammalian UPR is the protease presenilin-1. Mutations in the gene for presenilin-1 cause early-onset familial Alzheimer disease. Interestingly, inhibition of proteolysis by the ubiquitin-26S proteasome system has also been described for Alzheimer s disease. This suggests a link between UPR and ERAD in mammalian cells. The recently identified gene Mif1 is a possible candidate to form a direct link between UPR and ERAD in mammalian cells. The Mif1 gene is under the direct control of UPR. Mif1 is a trans-ER-membrane protein, with both the N- and the C-termini facing the cytoplasmic side of the ER membrane. It contains an N-terminal ubiquitin-like domain. It is anticipated that Mif1 may associate through its ubiquitin-like domain with the 26S proteasome, in this way connecting the protein degradation machinery to the ER membrane and resulting in an efficient ERAD.
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Vertegaal AC, Kuiperij HB, van Laar T, Scharnhorst V, van der Eb AJ, Zantema A. cDNA micro array identification of a gene differentially expressed in adenovirus type 5- versus type 12-transformed cells. FEBS Lett 2000; 487:151-5. [PMID: 11150499 DOI: 10.1016/s0014-5793(00)02339-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Proteins encoded by non-oncogenic adenovirus type 5 and oncogenic adenovirus type 12 differentially affect expression of a number of cellular genes. We have used cDNA micro array analysis to identify a cellular gene that is expressed in Ad12- but not in Ad5-transformed cells. This cellular gene was found to be the gene encoding follistatin-related protein, a TGF-beta inducible gene. Consistently, a constitutive factor binding to Smad binding elements was found in adenovirus type 12-transformed cells.
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van Laar T, Schouten T, Hoogervorst E, van Eck M, van der Eb AJ, Terleth C. The novel MMS-inducible gene Mif1/KIAA0025 is a target of the unfolded protein response pathway. FEBS Lett 2000; 469:123-31. [PMID: 10708769 DOI: 10.1016/s0014-5793(00)01253-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a search for genes induced by DNA-damaging agents, we identified two genes that are activated by methyl methanesulfonate (MMS). Expression of both genes is regulated after endoplasmic reticulum (ER) stress via the unfolded protein response (UPR) pathway. The first gene of those identified is the molecular chaperone BiP/GRP78. The second gene, Mif1, is identical to the anonymous cDNA KIAA0025. Treatment with the glycosylation inhibitor tunicamycin both enhances the synthesis of Mif1 mRNA and protein. The Mif1 5' flanking region contains a functional ER stress-responsive element which is sufficient for induction by tunicamycin. MMS, on the other hand, activates Mif1 via an UPR-independent pathway. The gene encodes a 52 kDa protein with homology to the human DNA repair protein HHR23A and contains an ubiquitin-like domain. Overexpressed Mif1 protein is localized in the ER.
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Neef C, van Laar T. Pharmacokinetic-pharmacodynamic relationships of apomorphine in patients with Parkinson's disease. Clin Pharmacokinet 1999; 37:257-71. [PMID: 10511920 DOI: 10.2165/00003088-199937030-00004] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In the treatment of patients with Parkinson's disease, apomorphine has an established place as a back-up therapy if other antiparkinsonian drugs, such as levodopa and oral dopamine agonists, have not controlled the existing response fluctuations. Apomorphine is a synthetic derivative of morphine, with a totally distinct pharmacological profile. It is a very lipophilic compound which is easily (auto)oxidised. This (auto)oxidation is the main metabolic route besides glucuronidation and sulphation, which are both responsible for about 10% of the metabolic transformation. Apomorphine quickly passes the nasal and intestinal mucosa as well as the blood-brain barrier (depending on the administration route). Many routes of administration have been explored, but subcutaneous, sublingual, nasal and rectal administration are used in clinical practice. The volume of distribution varies between 1 and 2 times bodyweight. The elimination half-life is very short (30 to 90 min) depending on the type of parenteral administration. Apomorphine is a high clearance drug (3 to 5 L/kg/h) and is mainly excreted and metabolised by the liver. Only 3 to 4% is excreted unchanged in the urine. The clinical effect of apomorphine can be linked directly to its concentration in the cerebrospinal fluid. Consequently, a 2-compartment model can be used to predict the clinical effects of apomorphine. The pharmacokinetic-pharmacodynamic data reflect the clinical observations of steep dose-effect curves if apomorphine is used in patients with random 'on-off' fluctuations. These dose-effect curves are less steep in stable or 'wearing-off' (end-of-dose deterioration) patients. Intravenous infusions of apomorphine in combination with timed motor assessments can be used clinically to characterise the therapeutic window of a particular patient if dyskinesia persists after single injections of apomorphine. If more population data become available, the population pharmacokinetics-pharmacodynamics of apomorphine could be helpful in predicting the clinical effects of apomorphine in the several subgroups of patients with Parkinson's disease.
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van Laar T, Van der Geest R, Danhof M. Future delivery systems for apomorphine in patients with Parkinson's disease. ADVANCES IN NEUROLOGY 1999; 80:535-44. [PMID: 10410768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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van Laar T, van der Geest R, Danhof M, Boddé HE, Goossens PH, Roos RA. Stepwise intravenous infusion of apomorphine to determine the therapeutic window in patients with Parkinson's disease. Clin Neuropharmacol 1998; 21:152-8. [PMID: 9617506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A new experimental strategy was applied to determine the concentration-effect relation and the therapeutic window of apomorphine in individual patients with Parkinson's disease. Apomorphine was administered by a stepwise intravenous infusion. The infusion rate was increased by 10 micrograms/kg/h every 20 minutes, up to 100 micrograms/kg/h or less when adverse effects occurred. Thereafter, the infusion rate was decreased in a stepwise fashion until zero. Plasma apomorphine concentrations were measured every 20 minutes. Clinical efficacy (tapping score and tremor), dyskinesia, and adverse effects were monitored at the same time. The mean clearance of apomorphine was 4.5 L/min (2.2 to 6.6 L/min). Of the 10 patients, 8 responded to apomorphine. The effects were quantal rather than continuous. Within each patient, the concentrations at onset and offset of effect generally were similar. Significant interpatient variability was observed with respect to minimal concentration for each of the effects. Clinical efficacy occurred at a mean minimal effective concentration (MEC) of 4.7 ng/mL (range 1.4 to 10.7 ng/mL). Dyskinesia was observed at a mean concentration of 8.5 ng/mL (range 2.7 to 20 ng/mL). This value was not significantly different from the MEC. The mean minimal toxic concentration was 16.7 ng/mL (8.5 to 24.5 ng/mL) and was significantly different from the mean MEC. In conclusion, the stepwise increase and decrease of the intravenous infusion rate is a suitable tool for the establishment of the concentration-effect relation of apomorphine in individual patients. The finding of a narrow therapeutic window, in which the onset concentrations vary from patient to patient, underlines the need for accurate and individualized dosing.
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van der Geest R, van Laar T, Kruger PP, Gubbens-Stibbe JM, Boddé HE, Roos RA, Danhof M. Pharmacokinetics, enantiomer interconversion, and metabolism of R-apomorphine in patients with idiopathic Parkinson's disease. Clin Neuropharmacol 1998; 21:159-68. [PMID: 9617507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The pharmacokinetics and metabolism of R-apomorphine were determined in 10 patients with idiopathic Parkinson's disease after intravenous infusion of 30 micrograms.kg-1 in 15 min. Specifically, emphasis was on enantiomeric interconversion into S-apomorphine and on the formation of apocodeine and isoapocodeine, since these metabolites may interfere with the pharmacodynamics of R-apomorphine. The pharmacokinetics of R-apomorphine in plasma were determined using an enantioselective high-performance liquid chromatography assay. In most patients, the plasma concentration versus time profile was characterized by a biexponential function. The values of relevant pharmacokinetic parameters were as follows: clearance 40 +/- 15 ml.min-1.kg-1, volume of distribution at steady state 1.6 +/- 0.5 l.kg-1, and terminal half-life 41 +/- 13 min. No measurable concentrations of S-apomorphine were detected in plasma, indicating that enantiomeric interconversion does not occur in vivo. Furthermore, no measurable concentrations of the methylated metabolites apocodeine and isoapocodeine could be detected in plasma. The metabolism of apomorphine was characterized on basis of the excretion of unchanged R-apomorphine, S-apomorphine, apocodeine, isoapocodeine, and their respective sulfate and glucuronide conjugates in urine. The total excretion of unconjugated S-apomorphine, apocodeine, and isoapocodeine was less than 0.1% of the administered dose. The total excretion of unchanged apomorphine, apomorphine sulfate, and apomorphine glucuronide amounted to 0.3 +/- 0.4%, 3.8 +/- 1% and 6.0 +/- 2.2% of the administered dose, respectively. The findings of this study show that on intravenous administration, S-apomorphine and the metabolites apocodeine and isoapocodeine are unlikely to interfere with the pharmacologic actions of R-apomorphine in patients with idiopathic Parkinson's disease. Furthermore, no pharmacokinetic interaction between R-apomorphine and catechol-O-methyl transferase inhibitors is expected.
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van Laar T, van Hilten B, Neef C, Rutgers AW, Pavel S, Bruijn JA. The role of EDTA in provoking allergic reactions to subcutaneous infusion of apomorphine in patients with Parkinson's disease: a histologic study. Mov Disord 1998; 13:52-5. [PMID: 9452326 DOI: 10.1002/mds.870130113] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
One of the formulations of apomorphine, used in clinical practice, contains sodium edetate (EDTA). EDTA is a chelator which indirectly prevents oxidation of apomorphine. A clinical and histologic study in four patients revealed that apomorphine with EDTA caused severe subcutaneous nodules, histologically characterized by an inflammatory infiltrate with a large amount of eosinophils, indicating a cell-mediated allergic reaction. After withdrawal of EDTA, this allergic component completely disappeared, which was accompanied clinically by less extensive nodule formation with a softer consistency. It is therefore recommended that EDTA be excluded from apomorphine formulations.
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van Laar T, Lammers GJ, Roos RA, Gerritsen JJ, Meinders AE. Antiparkinsonian drugs causing inappropriate antidiuretic hormone secretion. Mov Disord 1998; 13:176-8. [PMID: 9452348 DOI: 10.1002/mds.870130135] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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van der Geest R, van Laar T, Gubbens-Stibbe JM, Boddé HE, Danhof M. Iontophoretic delivery of apomorphine. II: An in vivo study in patients with Parkinson's disease. Pharm Res 1997; 14:1804-10. [PMID: 9453072 DOI: 10.1023/a:1012152401715] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE Transdermal transport rates of the dopamine agonist R-apomorphine were determined in patients with idiopathic Parkinson's disease (IPD). Apomorphine was applied by iontophoresis at two current densities. METHODS In ten patients apomorphine was applied passively for one hour. Thereafter, in the first five patients, a current density of 250 microA.cm-2 was applied for one hour and a current density of 375 microA.cm-2 in the second group. The individual pharmacokinetic parameters were obtained separately following a 15-minute zero-order intravenous infusion of 30 micrograms.kg-1. Skin resistance was measured during current delivery. Current-induced irritation was measured by Laser Doppler Flowmetry (LDF). The pharmacodynamics were quantified by a unilateral tapping score. Qualitative clinical improvements (decreased tremor, rigidity or cramp) were also recorded. RESULTS In all patients increasing plasma concentrations of R-apomorphine were found during the interval of current application. The maximum concentrations that were attained were related to the applied current density: 1.3 +/- 0.6 ng.ml-1 at 250 microA.cm-2 and 2.5 +/- 0.7 ng.ml-1 at 375 microA.cm-2. When the current was switched off all concentrations returned to baseline values in about 90 minutes. By mathematical deconvolution of the profiles it was shown that steady-state fluxes were reached within the one-hour interval of current driven transport Steady-state fluxes were calculated to be 69 +/- 30 nmol.cm-2.h-1 at 250 microA.cm-2 and 114 +/- 34 nmol.cm-2.h-1 at 375 microA.cm-2. Individual drug input rates were inversely related to the overall resistance. Significantly elevated LDF values were found after patch removal, indicating mild current induced erythema. Only subtherapeutic plasma concentrations were obtained in all patients except for one. CONCLUSIONS The results show that current-dependent delivery of apomorphine is possible in vivo at acceptable levels of skin irritation. Excellent correlation was found between the calculated in vivo transport rates and the rates that were previously obtained in vitro.
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van der Geest R, Kruger P, Gubbens-Stibbe JM, van Laar T, Bodde HE, Danhof M. Assay of R-apomorphine, S-apomorphine, apocodeine, isoapocodeine and their glucuronide and sulfate conjugates in plasma and urine of patients with Parkinson's disease. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1997; 702:131-41. [PMID: 9449564 DOI: 10.1016/s0378-4347(97)00370-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Analytical methods are described for the selective, rapid and sensitive determination of R- and S-apomorphine, apocodeine and isoapocodeine and the glucuronic acid and sulfate conjugates in plasma and urine. The methods involve liquid-liquid extraction followed by high-performance liquid chromatography with electrochemical detection. The glucuronide and sulfate conjugates are determined after enzymatic hydrolysis. For the assay of R- and S-apomorphine a 10 microm Chiralcel OD-R column is used and the voltage of the detector is set at 0.7 V. The mobile phase is a mixture of aqueous phase (pH 4.0)-acetonitrile (65:35, v/v). At a flow-rate of 0.9 ml min(-1) the total run time is ca. 15 min. The detection limits are 0.3 and 0.6 ng ml(-1) for R- and S- apomorphine, respectively (signal-to-noise ratio 3). The intra- and inter-assay variations are <5% in the concentration range of 2.5-25 ng ml(-1) for plasma samples, and <4% in the concentration range of 40-400 ng ml(-1) for urine samples. For the assay of apomorphine, apocodeine and isoapocodeine, a 5 microm C18 column was used and the voltage of the detector set at 0.825 V. Ion-pairing chromatography was used. The mobile phase is a mixture of aqueous phase (pH 3.0)-acetonitrile (75:25, v/v). At a flow-rate of 0.8 ml min(-1) the total run time is ca. 14 min. The detection limits of this assay are 1.0 ng ml(-1) for apomorphine and 2.5 ng ml(-1) for both apocodeine and isoapocodeine (signal-to-noise ratio 3). The inter-assay variations are 5% in the concentration range of 5-40 ng ml(-1) for plasma samples and 7% in the concentration range of 50-500 ng ml(-1) for urine samples. The glucuronic acid and sulfate conjugates of the various compounds are hydrolysed by incubation of the samples with beta-glucuronidase and sulfatase type H-1, respectively. Hydrolysis was complete after 5 h of incubation. No measurable degradation of apomorphine, apocodeine and isoapocodeine occurred during the incubation. A pharmacokinetic study of apomorphine, following the intravenous infusion of 30 microg kg(-1) for 15 min in a patient with Parkinson's disease, demonstrates the utility of the methods: both the pharmacokinetic parameters of the parent drug and the appearance of apomorphine plus metabolites in urine could be determined.
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Terleth C, van Laar T, Schouten R, van Steeg H, Hodemaekers H, Wormhoudt T, Cornelissen-Steijger PD, Abrahams PJ, van der Eb AJ. A lack of radiation-induced ornithine decarboxylase activity prevents enhanced reactivation of herpes simplex virus and is linked to non-cancer proneness in xeroderma pigmentosum patients. Cancer Res 1997; 57:4384-92. [PMID: 9331102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Patients with xeroderma pigmentosum (XP), a DNA repair disorder, run a large risk of developing skin cancer in sun-exposed areas. Cancer proneness in these patients correlates with a mammalian SOS-like response, "enhanced reactivation (ER) of viruses." Here, we report that radiation-induced activation of the ornithine decarboxylase (ODC) gene, a putative proto-oncogene, is required for this response. Various diploid fibroblast strains derived from a non-cancer-prone subclass of XP patients, which lack the ER response, were irradiated with 2 J/m2 and assessed for gene induction. In these fibroblasts, an absence of induction of ODC by UV-C was observed at the levels of mRNA, protein, and enzyme activity. This lack of induction is quite specific because the genes for fos and collagenase were induced as they were in normal XP cells. The apparent linkage between non-cancer proneness and a lack of ER and ODC induction was confirmed in a fibroblast strain derived from a patient with another DNA repair disorder, trichothiodystrophy, which does not lead to cancer proneness: in these cells, no induction of the ER response nor of ODC occurs after UV-C irradiation. Repair deficiency, however, is not essential because the simultaneous lack of ODC and ER induction after 10 J/m2 UV-C was found in at least one repair-proficient fibroblast. Next, a specific inhibitor of ODC, difluoromethylornithine, at a dose of 10 mM, completely blocked the ER response in cultured normal skin fibroblasts, suggesting that the ODC enzyme is in fact essential for the ER response. Difluoromethylornithine, although it did not affect other processes such as DNA repair, leads to a block in the cell division cycle at the G1-S transition. Interestingly, other blockers of this transition, wortmannin (500 nM) and mimosine (100 mM), also decreased the ER response. Finally, the ER and ODC responses also seem to be linked after treatment with X-irradiation (3 Gy), suggesting that both are part of a general response to DNA damage, at least in human skin fibroblasts. Apart from the abnormal ER and ODC responses, fibroblasts from non-tumor-prone XP patients react in the same way to radiation as do fibroblasts from tumor-prone XP patients with respect to other parameters. Thus, the lack of ODC induction after radiation may help to protect XP patients against skin carcinogenesis.
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van Hilten JJ, Wagemans EA, Ghafoerkhan SF, van Laar T. Movement characteristics in Parkinson's disease: determination of dopaminergic responsiveness and threshold. Clin Neuropharmacol 1997; 20:402-8. [PMID: 9331516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We evaluated the responsiveness of tap rate (TR), movement time (MT), and reaction time (RT) to intravenous (i.v.) (n = 10) and subcutaneous (s.c.) (n = 16) administration of apomorphine in patients with Parkinson's disease (PD). In the second part of this study, we evaluated the feasibility of the commonly used 15% TR threshold, above which a patient is considered to be a responder. Compared to MT, TR emerged as the most responsive measure of bradykinesia during both i.v. and s.c. administration of apomorphine. RT showed no response to dopaminergic stimulation. To evaluate the influence of threshold on the number of responsive sessions, we determined the baseline variability of TR by means of the coefficient of variation (CV) in 39 patients with PD. Our results show approximately similar numbers of responsive sessions using the 15% and 2CV threshold. Our findings suggest that a simple repetitive motor task--TR--is more responsive than is the MT task. Finally, the 15% threshold may be considered an adequate threshold for TR in assessment of dopaminergic responsiveness of bradykinesia.
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van Laar T, Neef C, Danhof M, Roon KI, Roos RA. A new sublingual formulation of apomorphine in the treatment of patients with Parkinson's disease. Mov Disord 1996; 11:633-8. [PMID: 8914088 DOI: 10.1002/mds.870110607] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A new formulation of a sublingual tablet with 10 mg apomorphine was examined in 13 patients with Parkinson's disease. Vitamin C (250 mg) was added sublingually to lower the salivary pH. Four patients received sublingual apomorphine and nine received sublingual apomorphine as well as vitamin C. Subcutaneous apomorphine was given to all patients. The study was designed as a randomized three-way cross-over study. Tmax, Cmax, and bioavailability (F) were determined. Clinical efficacy was assessed by hand-tapping during 30 s, walking time over 25 m, and a 4-point tremor score. The mean Tmax after subcutaneous apomorphine was 14.5 +/- 1.9 min with a mean Cmax of 19.2 +/- 3.8 ng/ml. The mean clearance of all patients was 3.8 +/- 0.6 L/min. The mean Tmax after sublingual apomorphine was 61.1 +/- 6.9 min vs. 61.7 +/- 8.2 min with vitamin C. The mean Cmax was 7.4 +/- 1.0 ng/ml (- vitamin C) vs. 4.3 +/- 1.3 ng/ml (+ vitamin C). These data resulted consequently in a not significantly different mean bioavailability, varying from 17.6% (- vitamin C) to 6.1% (+ vitamin C). The latency of onset of clinical efficacy varied between 25.0 +/- 8.5 min (- vitamin C) and 26.0 +/- 5.3 min (+ vitamin C). The duration of effect was lower (not significantly) when vitamin C was added: 88.0 +/- 12.5 min (- vitamin C) vs. 61.0 +/- 11.9 min (+ vitamin C). These data show that 10 mg apomorphine sublingually was effective in 56% of the patients. The combination with vitamin C did not significantly change the latency of onset or duration of clinical efficacy. Sublingual apomorphine should be considered as an alternative in the treatment of "off"-periods in Parkinson's disease, in particular when patients have the capacity to anticipate their off-periods.
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Shvarts A, Steegenga WT, Riteco N, van Laar T, Dekker P, Bazuine M, van Ham RC, van der Houven van Oordt W, Hateboer G, van der Eb AJ, Jochemsen AG. MDMX: a novel p53-binding protein with some functional properties of MDM2. EMBO J 1996. [DOI: 10.1002/j.1460-2075.1996.tb00919.x] [Citation(s) in RCA: 429] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Shvarts A, Steegenga WT, Riteco N, van Laar T, Dekker P, Bazuine M, van Ham RC, van der Houven van Oordt W, Hateboer G, van der Eb AJ, Jochemsen AG. MDMX: a novel p53-binding protein with some functional properties of MDM2. EMBO J 1996; 15:5349-57. [PMID: 8895579 PMCID: PMC452278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Here we report the isolation of a cDNA encoding a new p53-associating protein. This new protein has been called MDMX on the basis of its structural similarity to MDM2, which is especially notable in the p53-binding domain. In addition, the putative metal binding domains in the C-terminal part of MDM2 are completely conserved in MDMX. The middle part of the MDMX and MDM2 proteins shows a low degree of conservation. We can show by co-immunoprecipitation that the MDMX protein interacts specifically with p53 in vivo. This interaction probably occurs with the N-terminal part of p53, because the activity of the transcription activation domain of p53 was inhibited by co-transfection of MDMX. Northern blotting showed that MDMX, like MDM2, is expressed in all tissues tested, and that several mRNAs for MDMX can be detected. Interestingly, the level of MDMX mRNA is unchanged after UV irradiation, in contrast to MDM2 transcription. This observation suggests that MDMX may be a differently regulated modifier of p53 activity in comparison with MDM2. Our study indicates that at least one additional member of the MDM protein family exists which can modulate p53 function.
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