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An innovative method to strengthen evidence for potential drug safety signals using Electronic Health Records. J Med Syst 2024; 48:51. [PMID: 38753223 PMCID: PMC11098892 DOI: 10.1007/s10916-024-02070-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/25/2024] [Indexed: 05/19/2024]
Abstract
Reports from spontaneous reporting systems (SRS) are hypothesis generating. Additional evidence such as more reports is required to determine whether the generated drug-event associations are in fact safety signals. However, underreporting of adverse drug reactions (ADRs) delays signal detection. Through the use of natural language processing, different sources of real-world data can be used to proactively collect additional evidence for potential safety signals. This study aims to explore the feasibility of using Electronic Health Records (EHRs) to identify additional cases based on initial indications from spontaneous ADR reports, with the goal of strengthening the evidence base for potential safety signals. For two confirmed and two potential signals generated by the SRS of the Netherlands Pharmacovigilance Centre Lareb, targeted searches in the EHR of the Leiden University Medical Centre were performed using a text-mining based tool, CTcue. The search for additional cases was done by constructing and running queries in the structured and free-text fields of the EHRs. We identified at least five additional cases for the confirmed signals and one additional case for each potential safety signal. The majority of the identified cases for the confirmed signals were documented in the EHRs before signal detection by the Dutch Medicines Evaluation Board. The identified cases for the potential signals were reported to Lareb as further evidence for signal detection. Our findings highlight the feasibility of performing targeted searches in the EHR based on an underlying hypothesis to provide further evidence for signal generation.
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55P Real-world monitoring of hybrid dosing of pembrolizumab in stage IV non-small cell lung cancer in the Netherlands. J Thorac Oncol 2023. [DOI: 10.1016/s1556-0864(23)00309-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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A text-mining approach to study the real-world effectiveness and potentially fatal immune-related adverse events of PD-1 and PD-L1 inhibitors in older patients with stage III/IV non-small cell lung cancer. BMC Cancer 2023; 23:247. [PMID: 36918817 PMCID: PMC10015929 DOI: 10.1186/s12885-023-10701-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/03/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND This study was designed to investigate the impact of age on the effectiveness and immune-related adverse events (irAEs) of programmed death-(ligand)1 [PD-(L)1] inhibitors in patients with non-small cell lung cancer (NSCLC) using a novel text-mining technique. METHODS This retrospective study included patients with stage III/IV NSCLC treated with a PD-(L)1 inhibitor (nivolumab, pembrolizumab, atezolizumab and durvalumab) at Leiden University Medical Centre and Haga Teaching hospital, (both in The Netherlands) from September 2016 to May 2021. All the relevant data was extracted from the structured and unstructured fields of the Electronic Health Records using a novel text-mining tool. Effectiveness [progression-free survival (PFS) and overall survival (OS)] and safety (the incidence of nine potentially fatal irAEs and systemic corticosteroid requirement) outcomes were compared across age subgroups (young: < 65 years, Middle-aged: 65-74 years, and old: ≥ 75 years) after adjustment for confounding. RESULTS Of 689 patients, 310 patients (45.0%) were < 65 years, 275 patients (39.9%) were aged between 65 and 74 years, and 104 patients (15.1%) were ≥ 75 years. There was no significant difference between younger and older patients regarding PFS (median PFS 12, 8, 13 months respectively; Hazard ratio (HR)middle-aged = 1.14, 95% CI 0.92-1.41; HRold = 1.10, 95% CI 0.78-1.42). This was also the case for OS (median OS 19, 14, 18 months respectively; HRmiddle-aged = 1.22, 95% CI 0.96-1.53; HRold = 1.10, 95% CI 0.79-1.52). Safety analysis demonstrated a higher incidence of pneumonitis among patients aged 65-74. When all the investigated irAEs were pooled, there was no statistically significant difference found between age and the incidence of potentially fatal irAEs. CONCLUSIONS The use of PD-(L)1 inhibitors is not associated with age related decrease of PFS and OS, nor with increased incidence of serious irAEs compared to younger patients receiving these treatments. Chronological age must therefore not be used as a predictor for the effectiveness or safety of ICIs.
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812P Early experiences in adjuvant treatment of melanoma: Real-world data on tolerability, safety and efficacy. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Real-World Metastatic Renal Cell Carcinoma Treatment Patterns and Clinical Outcomes in The Netherlands. Front Pharmacol 2022; 13:803935. [PMID: 35401238 PMCID: PMC8983834 DOI: 10.3389/fphar.2022.803935] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/18/2022] [Indexed: 12/28/2022] Open
Abstract
The number of treatment options for patients with metastatic renal cell carcinoma (mRCC) has significantly grown in the last 15 years. Although randomized controlled trials are fundamental in investigating mRCC treatment efficacy, their external validity can be limited. Therefore, the efficacy of the different treatment options should also be evaluated in clinical practice. We performed a chart review of electronic health records using text mining software to study the current treatment patterns and outcomes. mRCC patients from two large hospitals in the Netherlands, starting treatment between January 2015 and May 2020, were included. Data were collected from electronic health records using a validated text mining tool. Primary endpoints were progression-free survival (PFS) and overall survival (OS). Statistical analyses were performed using the Kaplan-Meier method. Most frequent first-line treatments were pazopanib (n = 70), sunitinib (n = 34), and nivolumab with ipilimumab (n = 28). The overall median PFS values for first-line treatment were 15.7 months (95% confidence interval [95%CI], 8.8-20.7), 16.3 months (95%CI, 9.3-not estimable [NE]) for pazopanib, and 6.9 months (95% CI, 4.4-NE) for sunitinib. The overall median OS values were 33.4 months (95%CI, 28.1-50.9 months), 39.3 months (95%CI, 29.5-NE) for pazopanib, and 28.1 months (95%CI, 7.0-NE) for sunitinib. For nivolumab with ipilimumab, median PFS and median OS were not reached. Of the patients who finished first- and second-line treatments, 64 and 62% received follow-up treatments, respectively. With most patients starting on pazopanib and sunitinib, these real-world treatment outcomes were most likely better than in pivotal trials, which may be due to extensive follow-up treatments.
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Identification of Treosulfan-Induced Myalgia in Pediatric Hematopoietic Stem Cell Transplantation Using an Electronic Health Record Text Mining Tool. Transplant Cell Ther 2021. [DOI: 10.1016/s2666-6367(21)00220-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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An Electronic Health Record Text Mining Tool to Collect Real-World Drug Treatment Outcomes: A Validation Study in Patients With Metastatic Renal Cell Carcinoma. Clin Pharmacol Ther 2020; 108:644-652. [PMID: 32575147 PMCID: PMC7484987 DOI: 10.1002/cpt.1966] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/15/2020] [Indexed: 12/28/2022]
Abstract
Real‐world evidence can close the inferential gap between marketing authorization studies and clinical practice. However, the current standard for real‐world data extraction from electronic health records (EHRs) for treatment evaluation is manual review (MR), which is time‐consuming and laborious. Clinical Data Collector (CDC) is a novel natural language processing and text mining software tool for both structured and unstructured EHR data and only shows relevant EHR sections improving efficiency. We investigated CDC as a real‐world data (RWD) collection method, through application of CDC queries for patient inclusion and information extraction on a cohort of patients with metastatic renal cell carcinoma (RCC) receiving systemic drug treatment. Baseline patient characteristics, disease characteristics, and treatment outcomes were extracted and these were compared with MR for validation. One hundred patients receiving 175 treatments were included using CDC, which corresponded to 99% with MR. Calculated median overall survival was 21.7 months (95% confidence interval (CI) 18.7–24.8) vs. 21.7 months (95% CI 18.6–24.8) and progression‐free survival 8.9 months (95% CI 5.4–12.4) vs. 7.6 months (95% CI 5.7–9.4) for CDC vs. MR, respectively. Highest F1‐score was found for cancer‐related variables (88.1–100), followed by comorbidities (71.5–90.4) and adverse drug events (53.3–74.5), with most diverse scores on international metastatic RCC database criteria (51.4–100). Mean data collection time was 12 minutes (CDC) vs. 86 minutes (MR). In conclusion, CDC is a promising tool for retrieving RWD from EHRs because the correct patient population can be identified as well as relevant outcome data, such as overall survival and progression‐free survival.
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Effectiveness and toxicity of lenvatinib in refractory thyroid cancer: Dutch real-life data. Eur J Endocrinol 2020; 182:131-138. [PMID: 31751307 DOI: 10.1530/eje-19-0763] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/14/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The SELECT trial showed progression-free survival (PFS) benefit for lenvatinib for advanced radioiodine-refractory differentiated thyroid cancer (RAI-refractory or RR-DTC) patients, on which current clinical practice is based. We assessed whether the effectiveness and toxicity of lenvatinib in real-life clinical practice in the Netherlands were comparable to the pivotal SELECT trial. METHODS From three Dutch centres Electronic Health Records (EHRs) of patients treated in the lenvatinib compassionate use program or as standard of care were reviewed and checked for SELECT eligibility criteria. Baseline characteristics, safety, and efficacy measures were compared and PFS and overall survival (OS) were calculated. Furthermore, PFS was compared to estimates of PFS reported in other studies. RESULTS A total of 39 DTC patients with a median age of 62 years were analysed. Of these, 27 patients (69%) did not fulfil the SELECT eligibility criteria. The most common grade ≥3 toxicities were hypertension (n = 11, 28%), diarrhoea (n = 7, 18%), vomiting (n = 4, 10%), and gallbladder disease (n = 3, 8%). Median PFS and median OS were 9.7 (95% confidence interval (CI): 4.0-15.5) and 18.3 (95% CI: 4.9-31.7) months, respectively, response rate was 38% (95% CI: 23-54%). PFS in the Dutch real-life situation was comparable to previous real-life studies, but inferior to PFS as shown in the SELECT trial (P = 0.04). CONCLUSIONS PFS in our non-trial population was significantly shorter than in the SELECT trial population. In the interpretation of results, differences in the real-life population and the SELECT study population regarding patient characteristics should be taken into account.
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Population pharmacokinetics of treosulfan in paediatric patients undergoing hematopoietic stem cell transplantation. Br J Clin Pharmacol 2019; 85:2033-2044. [PMID: 31144349 PMCID: PMC6710524 DOI: 10.1111/bcp.13995] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 05/03/2019] [Accepted: 05/15/2019] [Indexed: 12/17/2022] Open
Abstract
Aims Treosulfan is an alkylating agent increasingly used prior to haematopoietic stem cell transplantation. The aim of this study was to develop a population pharmacokinetic (PK) model of treosulfan in paediatric haematopoietic stem cell transplantation recipients and to explore the effect of potential covariates on treosulfan PK. Also, a limited sampling model (LSM) will be developed to accurately predict treosulfan exposure suitable for a therapeutic drug monitoring setting. Methods In this multicentre study, 91 patients, receiving a total dose of 30, 36 or 42 g/m2 treosulfan, administered over 3 consecutive days, were enrolled. A population PK model was developed and demographic factors, as well as laboratory parameters, were included as potential covariates. In addition, a LSM was developed using data from 28 patients. Results A 2‐compartment model with first order elimination best described the data. Bodyweight with allometric scaling and maturation function were identified as significant predictors of treosulfan clearance. Treosulfan clearance reaches 90% of adult values at 4 postnatal years. A model‐based dosing table is presented to target an exposure of 1650 mg*h/L (population median) for different weight and age groups. Samples taken at 1.5, 4 and 7 hours after start of infusion resulted in the best limited sampling strategy. Conclusions This study provides a treosulfan population PK model in children and captures the developmental changes in clearance. A 3‐point LSM allows for accurate and precise estimation of treosulfan exposure.
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High interpatient variability of treosulfan exposure is associated with early toxicity in paediatric HSCT: a prospective multicentre study. Br J Haematol 2017; 179:772-780. [DOI: 10.1111/bjh.14960] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/21/2017] [Indexed: 12/23/2022]
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Studying the Optimal Intravenous Busulfan Exposure in Pediatric Allogeneic Hematopoietic Cell Transplantation (alloHCT) to Improve Clinical Outcomes: A Multicenter Study. Biol Blood Marrow Transplant 2015. [DOI: 10.1016/j.bbmt.2014.11.124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Effect of genetic variants GSTA1 and CYP39A1 and age on busulfan clearance in pediatric patients undergoing hematopoietic stem cell transplantation. Pharmacogenomics 2014; 14:1683-90. [PMID: 24192117 DOI: 10.2217/pgs.13.159] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Busulfan is used in preparative regimens prior to stem cell transplantation in pediatric patients. There is significant interpatient variability in busulfan pharmacokinetics (PK) and exposure is related to outcome. To date, only polymorphisms in genes encoding for glutathione-S-transferases were studied, but could only explain a small portion of the variability in PK. AIM To investigate the effect of seven genetic markers on busulfan clearance and the effect of ontogenesis on these genetic variants in a pediatric population. MATERIALS & METHODS In an earlier study of our group seven genetic markers in GSTA1, CYP2C19, CYP39A1, ABCB4, SLC22A4 and SLC7A8 were associated with busulfan clearance in adult patients. Eighty four pediatric patients were genotyped for these markers and genotype was associated with busulfan clearance. RESULTS & CONCLUSION GSTA1 and CYP39A1 were found to be associated with busulfan clearance. When combined, the two haplotypes explained 17% of the variability in busulfan clearance. Furthermore, the effect of GSTA1 haplotype on clearance was dependent on age.
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Evaluation of rule effectiveness and positive predictive value of clinical rules in a Dutch clinical decision support system in daily hospital pharmacy practice. Artif Intell Med 2013; 59:15-21. [DOI: 10.1016/j.artmed.2013.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 04/03/2013] [Accepted: 04/06/2013] [Indexed: 11/28/2022]
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PHC-014 Exploratory Analysis of 1,936 SNPs in 225 ADME Genes For Association with Busulfan Clearance in Adult Hematopoietic Stem Cell Recipients. Eur J Hosp Pharm 2013. [DOI: 10.1136/ejhpharm-2013-000276.359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Diagnostic and therapeutic management for suspected neonatal herpes simplex virus infection. J Clin Virol 2011; 51:8-11. [DOI: 10.1016/j.jcv.2011.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 10/18/2022]
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Effect of genetic polymorphisms in genes encoding GST isoenzymes on BU pharmacokinetics in adult patients undergoing hematopoietic SCT. Bone Marrow Transplant 2011; 47:190-5. [DOI: 10.1038/bmt.2011.55] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Optimizing the Busulfan Dosing Regimen to Get a More Predictable Exposure: A Data Driven Analysis. Biol Blood Marrow Transplant 2011. [DOI: 10.1016/j.bbmt.2010.12.086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Targeting to an Optimal AUC of Intravenous Busulfan Prevents Graft Failure In Transplantation In Children With Non-Malignant Diseases. Biol Blood Marrow Transplant 2009. [DOI: 10.1016/j.bbmt.2008.12.236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Surprising result after evaluating a nurse-driven guideline on blood glucose management. Crit Care 2009. [PMCID: PMC4084007 DOI: 10.1186/cc7285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Soluble triggering receptor expressed on myeloid cells-1 in bronchoalveolar lavage is not predictive for ventilator-associated pneumonia. Crit Care 2008. [PMCID: PMC4088420 DOI: 10.1186/cc6270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Intravenous busulfan in children prior to stem cell transplantation: study of pharmacokinetics in association with early clinical outcome and toxicity. Bone Marrow Transplant 2005; 35:17-23. [PMID: 15502853 DOI: 10.1038/sj.bmt.1704707] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We studied the pharmacokinetics of intravenous busulfan (Bu) in children in order to further optimize intravenous Bu dosing in relation to toxicity and survival. A total of 31 children undergoing Bu-based conditioning for allogeneic SCT were enrolled in a study. The starting dose was 1.0 mg/kg (age < 4 years) and 0.8 mg/kg (age > or =4 years), four doses per day during 4 days. Dose adjustment was allowed up to a maximum dose of 1.0 mg/kg per dose if the target area under the serum concentration-time curve (AUC) was not reached. Pharmacokinetic studies were performed after the first dose. Donor engraftment was established in 28 out of 31 patients. The average AUC after the first dose was the same in children < 4 years as in children > or =4 years. Mean clearance was higher in children < 4 years than in children > or =4 years. In 35% of all patients, total AUC was within the target AUC. The other children's AUCs were below the target range. No relationships were found between systemic exposure to Bu and toxicity or clinical outcome. We concluded that, in accordance with previous data, within the observed AUCs no clear relationship was observed between Bu AUC and outcome with respect to toxicity, engraftment and relapse.
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Abstract
BACKGROUND Postoperative analgesia in children may be improved by using tramadol. The pharmacokinetics of rectal tramadol in young children were therefore investigated. METHODS The pharmacokinetics of rectal tramadol and its active metabolite were studied in 12 young children (age: 1-6 yr) postoperatively. On the basis of these data, a population model was constructed. Using this model, the pharmacokinetics of different doses of tramadol were calculated. RESULTS The pharmacokinetics of rectal tramadol could be adequately described by a one-compartment model. The pharmacokinetic parameters derived from the model indicate that a low variability was present. Elimination half-life was 4.3 (0.2) h (sem) and the apparent clearance was 16.4 (1.5) litre h(-1) (sem). CONCLUSIONS The study showed that after rectal administration, tramadol is absorbed at a reasonable rate and with a low inter-individual variability in small children. The data also suggested that a rectal dose of tramadol 1.5-2.0 mg kg(-1) is therapeutic.
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A clinical trial comparing rectal diclofenac and tramadol for post-operative analgesia in children. Clin Pharmacol Ther 2003. [DOI: 10.1016/s0009-9236(03)90623-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thyroid status affects the rat cardiac beta-adrenoceptor system transiently and time-dependently. JOURNAL OF AUTONOMIC PHARMACOLOGY 1998; 18:1-11. [PMID: 9728320 DOI: 10.1046/j.1365-2680.1998.1810001.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The aim of this study was to investigate the time-dependency of the influence of dysthyroid states on the beta-adrenoceptor system in rat heart left ventricle. Therefore, the influence of acute and chronic hyper- and hypothyroidism on beta-adrenoceptor-induced left ventricular responses, beta-adrenoceptor density, cardiac noradrenaline tissue concentrations, Gs alpha-proteins, and basal and stimulated adenylate cyclase activities was determined. 2. Hyperthyroid rats were obtained by feeding with thyroxine (T4)-containing rat-chow for 1, 4 and 8 weeks. Hypothyroidism was induced by adding 0.05% propylthiouracil (PTU) to the drinking water. Rats of varying ages were used in order to compensate for the differences in the duration of the treatments. Rats were aged 3 and 5 months at the end of the experiments. 3. Thyroxine treatment for 4 and 8 weeks increased the cardiac sensitivity to isoprenaline, but maximal induced inotropic responses were decreased. Cardiac ventricular beta-adrenoceptor density was increased only in rats treated with T4 for 1 week. This transient effect of hyperthyroidism on cardiac beta-adrenoceptor density was not observed in older rats. The PTU treatment resulted in a stable decrease of cardiac beta-adrenoceptor density. 4. Left ventricular tissue noradrenaline concentrations were unaffected by hyperthyroidism, where a decrease was observed in hypothyroid rats. Density of Gs alpha proteins was increased in hearts from chronic hyperthyroid rats. 5. These results indicate that the increased sensitivity to beta-adrenoceptor-mediated stimulation in chronic hyperthyroidism cannot be attributed to changes in cardiac beta-adrenoceptor density, but is probably caused by an enhanced content of Gs alpha. Accordingly, in hyperthyroidism, the beta-adrenoceptor system is influenced time-dependently, whereas hypothyroidism affects the beta-adrenoceptor system independent of time.
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The influence of hyperthyroidism on vasoconstrictor and vasodilator responses in isolated coronary and renal resistance arteries. Pharmacology 1997; 55:117-25. [PMID: 9346400 DOI: 10.1159/000139519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The influence of hyperthyroidism on the functional vascular responsiveness of isolated coronary and renal resistance vessels was investigated. Hyperthyroidism was established by feeding rats for 1 and 4 weeks with 5 mg/kg L-thyroxine (T4)-containing rat chow. Preparations of either coronary or renal resistance vessels were mounted in an isometric wire myograph. Subsequently, concentration-effect curves were determined for the effects of 5-hydroxytryptamine (5-HT), 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F2alpha (U46619) and isoproterenol in coronary vessels, and for those of methoxamine, U46619 and isoproterenol in renal vessel preparations. Our results indicate that hyperthyroidism does not induce major changes in the sensitivity of both coronary and renal resistance vessels towards 5-HT, U46619 and methoxamine. A clearly sensitizing influence of acute hyperthyroidism (1 week of T4 treatment) was found for isoproterenol-induced relaxant responses, whereas hyperthyroidism for 4 weeks did not influence the responses mediated by isoproterenol in coronary resistance arteries. Furthermore, the isoproterenol-induced relaxation in renal arteries was not influenced by the chronic hyperthyroid state of the animal. The present results indicate that in acute hyperthyroidism beta-adrenoceptor-mediated vasodilation is increased. However, in chronic hyperthyroidism changes in responsiveness to vasoconstrictor or vasodilator agents of coronary and renal resistance arteries appear not to play a major role. The influence of hyperthyroidism on the functional response of resistance arteries appears to be both tissue and time dependent.
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Abstract
The direct relaxant effects of thyroid hormones on mesenteric resistance vessels were investigated using an isometric wire myograph. Both the L- and the D-isomers of thyroxine (T4) and triiodothyronine (T3) were studied. In contrast with the long-term effects of thyroid hormones, both T4 enantiomers proved more potent in inducing vascular relaxation than the two T3 enantiomers. The interaction between thyroid hormones and calcium-induced contractions was studied. T4 concentration dependently inhibited the Ca2+ induced contractions, showing noncompetitive interaction. Furthermore, we investigated whether the endothelium was involved in the relaxant effect to L-T4. The T4 induced relaxation proved impaired by prior incubation with the nitric oxide (NO) inhibitor N-omega-nitro-L-arginine methylester HCl (L-NAME, 0.1 microM), indicating that T4 is able to stimulate the production of endothelium-derived NO. L-T4-induced relaxation was enhanced by prior incubation with indomethacin (10 microM), whereas in endothelium-denuded preparations an unaltered response was found. The present results indicate that L-T4-induced relaxation is established by an indirect effect via the endothelium and by a direct effect on vascular smooth muscle cells, possibly by influencing calcium fluxes. Because vascular relaxation is established at supraphysiologic concentrations (approximately 100 times the basal level) of thyroid hormone, it is concluded that the direct effect of thyroid hormone on mesenteric vascular smooth muscle cells are not relevant for the in vivo situation.
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Thyroid hormone modulates inotropic responses, alpha-adrenoceptor density and catecholamine concentrations in the rat heart. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1996; 354:755-64. [PMID: 8971736 DOI: 10.1007/bf00166902] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the influence of hyper- and hypothyroidism on basal parameters of isolated perfused hearts of rats. In addition the effects of different extracellular calcium concentrations ([Ca2+]o), the calcium entry promoter Bay K8644 and the alpha 1-adrenoceptor agonist methoxamine were investigated. Since alterations in alpha-adrenoceptor density could explain the increased sensitivity to methoxamine in hearts from hypothyroid rats, alpha 1-adrenoceptor density in the left ventricle was also established. Different time-schedules of exposure to hyper- and hypothyroidism were used to investigate whether the influence of chronic dysthyroid states on alpha 1-adrenoceptor density is transient and time-dependent. Simultaneously myocardial noradrenaline and adrenaline tissue concentrations were determined, since they might correlate with the observed changes. Hyperthyroidism was induced by feeding rats for 1, 4 and 8 weeks with 5 mg/kg L-thyroxine (T4)-containing rat chow. Hypothyroid rats were obtained by adding 0.05% propylthiouracil (PTU) to the drinking water during 1, 4 and 8 weeks. For the functional experiments animals were treated during 4 weeks, to mimic the clinical situation of a chronic endocrine disease. Langendorff hearts from hyperthyroid hearts showed an increased maximally developed relaxation velocity, whereas Langendorff hearts from hypothyroid rats showed an increased left ventricular pressure (LVP). We observed an increased maximal inotropic response to [Ca2+]o in hearts from both hyperthyroid and hypothyroid rats, indicating that both dysthyroid states interfere with the handling of calcium ions by the contractile apparatus. Unchanged responses to Bay K8644 in hearts from hyperthyroid and depressed responses in hearts from hypothyroid rats suggest that the involvement of L-type calcium channels is rather unlikely. Furthermore, the reflex increase in coronary flow in response to enhanced contractile force appeared to fail in hearts from hypothyroid rats. Sensitivity of the response to methoxamine was increased in hearts from hypothyroid rats, which was accompanied by a decrease in the number of myocardial alpha 1-adrenoceptors. Both T4 and PTU treatment resulted in a non-transient decrease of alpha 1-adrenoceptor density in left ventricular tissue. Furthermore, hypothyroidism increased the percentage of alpha 1A-binding sites, whereas in hyperthyroidism the distribution of the alpha 1-adrenoceptor subtypes was not affected. Myocardial tissue concentrations of noradrenaline and adrenaline were unchanged in hyperthyroid rats and decreased in hypothyroid rats. The present study indicates that thyroid hormones have a direct rather than a sympathetically mediated effect on alpha 1-adrenoceptor mediated myocardial functions.
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The influence of hyperthyroidism on pharmacologically induced contractions of isolated resistance arteries. Eur J Pharmacol 1996; 300:91-7. [PMID: 8741171 DOI: 10.1016/0014-2999(95)00863-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We investigated the effect of hyperthyroidism on the responses of small mesenteric resistance arteries to several contractile and dilator agents. Hyperthyroidism was established by feeding rats for 28 days with 5 mg/kg L-thyroxine-containing rat chow. This treatment produced a stable hyperthyroid state, as indicated by the increased serum T4 levels (236 +/- 7 vs. 60 +/- 2; T4-treated vs. control). Preparations of small mesenteric arteries were mounted in an isometric wire myograph. Subsequently, concentration-effect curves were determined for K+, Ca2+, methoxamine, phenylephrine, 5-hydroxytryptamine (5-HT), 9,11-dideoxy-11 alpha, 9 alpha-epoxymethano-prostaglandin F2 alpha (U46619), methacholine and nitroprusside. Our results indicate that hyperthyroidism does not induce major changes in the sensitivity of isolated resistance vessels to K+, Ca+, the alpha-adrenoceptor agonist, methacholine and nitroprusside. Furthermore, neither the affinity of alpha-receptors for methoxamine, nor the alpha-receptor reserve was influenced by the hyperthyroid state of the animal. A clearly sensitizing influence of hyperthyroidism was found for the vasoconstrictor effects of both 5-HT (6.57 +/- 0.04 vs. 6.29 +/- 0.06; hyperthyroid vs. control) and the thromboxane A2 receptor agonist U46619 (6.78 +/- 0.13 vs. 6.30 +/- 0.09; hyperthyroid vs. control). Sensitization to both 5-HT and U46619 was abolished in the presence of N omega-nitro-L-arginine methylester HCl (L-NAME, 0.1 mM). 5-HT-induced contractions in vessels from hyperthyroid rats were diminished by prior incubation with indomethacin (10 microM). The present results indicate that during hyperthyroidism resistance vessels are sensitized to both 5-HT and U46619. This sensitization involves the nitric oxide/L-arginine pathway and probably also certain steps in the cyclooxygenase pathway.
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The influence of hyperthyroidism on beta-adrenoceptor-mediated relaxation of isolated small mesenteric arteries. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1996; 353:438-44. [PMID: 8935711 DOI: 10.1007/bf00261441] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the influence of hyperthyroidism on relaxant responses of small mesenteric resistance arteries to beta-adrenoceptor agonists and to compounds stimulating the corresponding second-messenger system. Hyperthyroidism was induced by feeding rats for 28 days with 5 mg/kg L-thyroxine (T4)-containing rat chow. This treatment produced a stable hyperthyroid state, as indicated by several biochemical/metabolic and haemodynamic parameters. Preparations of small mesenteric arteries were mounted in an isometric wire myograph. Subsequently, concentration-effect curves were determined for isoproterenol, noradrenaline and salbutamol as well as for forskolin, dibutyryl-cAMP and theophylline. We also determined concentration-effect curves to the beta-adrenoceptor agonists in the presence of ICI 118,551 and CGP 20712A (i.e., in the presence of a selective beta 2- and beta 1-adrenoceptor antagonist, respectively). Apparent pA2-values were calculated to determine which beta-adrenoceptor subtype causes vasodilation. These experiments indicate that beta-adrenoceptor-mediated vasodilation involves both beta 1- and beta 2-adrenoceptors in mesenteric resistance vessels of both hyperthyroid and control rats. In our experiments hyperthyroidism has a sensitizing influence on vascular responses induced by the beta-adrenoceptor agonist isoproterenol and the selective beta 2-adrenoceptor agonist salbutamol. Sensitization to isoproterenol was abolished in the presence of ICI 118,551, whereas it was emphasized in the presence of CGP 20712A. Although this was not fully supported by the results obtained with noradrenaline, these results indicate that the sensitization to beta-adrenoceptor agonists is probably limited to the beta 2-adrenoceptor/G-protein complex and not associated with alterations of the corresponding second messenger system.
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Characterization of extracellular GABA in the substantia nigra reticulata by means of brain microdialysis. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1992; 345:661-5. [PMID: 1635589 DOI: 10.1007/bf00164580] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Brain microdialysis was used to characterize extracellular gamma-aminobutyric acid (GABA) in the substantia nigra reticulata (SNR) of freely moving rats. The extracellular GABA in the SNR was characterized using acutely implanted probes (4-8 h after surgery; day 1) and chronically implanted probes (24 h after surgery; day 2). 3-Mercaptopropionic acid, a glutamic acid decarboxylase inhibitor, was used to identify GABA. This drug induced an immediate decrease in the extracellular GABA levels to 40% of basal values, suggesting that the detected GABA is, at least in part, newly synthesized. The basal levels of extracellular GABA measured either on day 1 or day 2 were not affected by infusion of micromolar amounts of tetrodotoxin. Therefore, a direct coupling between GABA dialysate concentrations and nerve-impulse flow does not seem to exist. Infusion of the GABA uptake inhibitor nipecotic acid (0.5 mmol/l) resulted in a 4-fold increase in the dialysate levels of GABA lasting at least for 3 h on both days. K+ stimulation (60 mmol/l) increased extracellular GABA levels in the SNR to 450% of basal values. This effect again did not differ significantly on day 1 and day 2. The origin of the extracellular GABA in the SNR, as recorded by microdialysis under the two experimental conditions, is discussed.
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