IU Indianapolis ScholarWorks :: Browsing by Author "Decker, Brian S."

Browsing by Author "Decker, Brian S."

Now showing 1 - 10 of 12

1-Alpha, 25-dihydroxyvitamin D3 alters the pharmacokinetics of mycophenolic acid in renal transplant recipients by regulating two extrahepatic UDP-glucuronosyltransferases 1A8 and 1A10
(Elsevier, 2016-12) Wang, Xiaoliang; Wang, Hongwei; Shen, Bing; Overholser, Brian R.; Cooper, Bruce R.; Lu, Yinghao; Tang, Huamei; Zhou, Chongzhi; Sun, Xing; Zhong, Lin; Favus, Murray J.; Decker, Brian S.; Liu, Wanqing; Peng, Zhihai; Department of Medicine, IU School of Medicine
Mycophenolic acid (MPA) is an important immunosuppressant broadly used in renal transplantation. However, the large inter-patient variability in mycophenolic acid (MPA) pharmacokinetics (PK) limits its use. We hypothesize that extrahepatic metabolism of MPA may have significant impact on MPA PK variability. Two intestinal UDP-glucuronosyltransferases 1A8 and 1A10 plays critical role in MPA metabolism. Both in silico and previous genome-wide analyses suggested that vitamin D (VD) may regulate intestinal UGT1A expression. We validated the VD response elements (VDREs) across the UGT1A locus with chromatin immunoprecipitation (ChIP) and luciferase reporter assays. The impact of 1-alpha,25-dihydroxyvitamin D3 (D3) on UGT1A8 and UGT1A10 transcription and on MPA glucuronidation was tested in human intestinal cell lines LS180, Caco-2 and HCT-116. The correlation between transcription levels of VD receptor (VDR) and the two UGT genes were examined in human normal colorectal tissue samples (n = 73). PK alterations of MPA following the parent drug, mycophenolate mofetil (MMF), and D3 treatment was assessed among renal transplant recipients (n = 10). Our ChIP assay validate three VDREs which were further demonstrated as transcriptional enhancers with the luciferase assays. D3 treatment significantly increased transcription of both UGT genes as well as MPA glucuronidation in cells. The VDR mRNA level was highly correlated with that of both UGT1A8 and UGT1A10 in human colorectal tissue. D3 treatment in patients led to about 40% reduction in both AUC0-12 and Cmax while over 70% elevation of total clearance of MPA. Our study suggested a significant regulatory role of VD on MPA metabolism and PK via modulating extrahepatic UGT activity.
Aldosterone: Yet Another Path to Blood Pressure Variability and Target Organ Damage
(Wiley, 2015) Decker, Brian S.; Pratt, Howard J.; Medicine, School of Medicine
Angiotensin-related genetic determinants of cardiovascular disease in patients undergoing hemodialysis
(Oxford University Press, 2019-11) Moe, Sharon M.; Long, Jin; Schwantes-An, Tae-Hwi Linus; Decker, Brian S.; Wetherill, Leah; Edenberg, Howard J.; Xuei, Xiaoling; Vatta, Matteo; Foroud, Tatiana M.; Chertow, Glenn M.; Medicine, School of Medicine
BACKGROUND: Cardiovascular mortality in patients receiving dialysis remains unacceptably high, with unexplained ancestry differences suggesting a genetic component. METHODS: We analyzed DNA samples from 37% of subjects enrolled in the EValuation Of Cinacalcet Hydrochloride (HCl) Therapy to Lower CardioVascular Events (EVOLVE) trial, a randomized trial conducted in patients receiving hemodialysis with secondary hyperparathyroidism, comparing cinacalcet to placebo on a background of usual care. DNA was analyzed for single-nucleotide polymorphisms (SNPs) in the genes encoding the angiotensin-converting enzyme receptor type I (AGTR1) and angiotensin-converting enzyme (ACE). Survival analyses were conducted separately in European Ancestry (EA) and African Ancestry (AfAn) due to known differences in cardiovascular events, minor alleles for the same variant and the frequency of minor alleles. Our primary determination was a meta-analysis across both races. RESULTS: Meta-analysis showed significant associations between rs5186 in AGTR1 and increased rates by 25-34% for the primary endpoint (composite of death or nonfatal myocardial infarction, hospitalization for unstable angina, heart failure or peripheral vascular event), all-cause mortality, cardiovascular mortality and heart failure; all P < 0.001. Three correlated SNPs in ACE were associated with lower rates of sudden cardiac death (SCD) in EA samples. One ACE SNP, rs4318, only found in the AfAn samples, was associated with a lower rate of SCD in the AfAn samples. CONCLUSIONS: The C allele in rs5186 in AGTR1 was associated with higher rates of death and major cardiovascular events in a meta-analysis of EA and AfAn patients with end-stage kidney disease. SNPs in ACE were associated with SCD.
Drug–gene and drug–drug interactions associated with tramadol and codeine therapy in the INGENIOUS trial
(Future Medicine, 2019-04) Fulton, Cathy R.; Zang, Yong; Desta, Zeruesenay; Rosenman, Marc B.; Holmes, Ann M.; Decker, Brian S.; Zhang, Yifei; Callaghan, John T.; Pratt, Victoria M.; Levy, Kenneth D.; Gufford, Brandon T.; Dexter, Paul R.; Skaar, Todd C.; Eadon, Michael T.; Medicine, School of Medicine
Background: Tramadol and codeine are metabolized by CYP2D6 and are subject to drug-gene and drug-drug interactions. Methods: This interim analysis examined prescribing behavior and efficacy in 102 individuals prescribed tramadol or codeine while receiving pharmaco-genotyping as part of the INGENIOUS trial (NCT02297126). Results: Within 60 days of receiving tramadol or codeine, clinicians more frequently prescribed an alternative opioid in ultrarapid and poor metabolizers (odds ratio: 19.0; 95% CI: 2.8-160.4) as compared with normal or indeterminate metabolizers (p = 0.01). After adjusting the CYP2D6 activity score for drug-drug interactions, uncontrolled pain was reported more frequently in individuals with reduced CYP2D6 activity (odds ratio: 0.50; 95% CI: 0.25-0.94). Conclusion: Phenoconversion for drug-drug and drug-gene interactions is an important consideration in pharmacogenomic implementation; drug-drug interactions may obscure the potential benefits of genotyping.
Gentamicin pharmacokinetics and pharmacodynamics during short-daily hemodialysis
(S. Karger AG, 2012) Decker, Brian S.; Mohamed, Ahmed N.; Chambers, Mary; Kraus, Michael A.; Moe, Sharon M.; Sowinski, Kevin M.; Department of Medicine, IU School of Medicine
BACKGROUND/AIMS: Gentamicin pharmacokinetics have not been described in patients undergoing short-daily hemodialysis (SDHD). The aim of this study is to describe gentamicin pharmacokinetics and dialytic clearance (Cl(dial)) in SDHD patients and simulate gentamicin exposure after six dosing regimens to help guide future dosing. METHODS: Six anuric patients undergoing SDHD were enrolled. Patients received intravenous infusion of 2 mg/kg gentamicin on day 1 after the first HD session followed by HD sessions on days 2, 3, and 4. Blood samples for determination of gentamicin concentrations were serially collected. Gentamicin pharmacokinetic parameters and Cl(dial) and interindividual variability terms (IIV) were estimated using NONMEM VII. Influence of patient weight on systemic clearance (Cl(s)) and central volume of distribution (V(c)) and influence of urea removal estimates on Cl(dial) were assessed. The model was used to simulate gentamicin concentrations after six dosing regimens including pre- and postdialysis as well as daily and every-other-day dosing. RESULTS: A two-compartment model with first-order elimination from central compartment described gentamicin pharmacokinetics. Population estimates for Cl(s) and Cl(dial) were 7.6 and 134 ml/min, respectively. Patient weight was statistically significantly associated with Cl(s) and V(c). Predialysis every-other-day regimens were as effective (C(max) ≥8 mg/l and AUC(48 h) ≥140 mg·h/l) and less toxic (C(min) <2 mg/l and AUC(48 h) <240 mg·h/l) than postdialysis regimens. CONCLUSIONS: Estimated gentamicin Cl(dial) is higher than previous estimates with thrice-weekly regimens. Predialysis every-other-day dosing may be recommended during SDHD.
Knowledge and Awareness Among Patients with Chronic Kidney Disease Stage 3
(American Nephrology Nurses Association, 2016) Welch, Janet L.; Bartlett Ellis, Rebecca J.; Perkins, Susan M.; Johnson, Cynthia S.; Zimmerman, Lani M.; Russell, Cynthia L.; Richards, Christine; Guise, David M.; Decker, Brian S.; School of Nursing
Knowledge is a prerequisite for changing behavior, and is useful for improving outcomes and reducing mortality rates in patients diagnosed with chronic kidney disease (CKD). The purpose of this article is to describe baseline CKD knowledge and awareness obtained as part of a larger study testing the feasibility of a self-management intervention. Thirty patients were recruited who had CKD Stage 3 with coexisting diabetes and hypertension. Fifty-four percent of the sample were unaware of their CKD diagnosis. Participants had a moderate amount of CKD knowledge. This study suggests the need to increase knowledge in patients with CKD Stage 3 to aid in slowing disease progression.
Pharmacogenomically actionable medications in a safety net health care system
(2016) Carpenter, Janet S.; Rosenman, Marc B.; Knisely, Mitchell R.; Decker, Brian S.; Levy, Kenneth D.; Flockhart, David A.; IU School of Nursing
OBJECTIVE: Prior to implementing a trial to evaluate the economic costs and clinical outcomes of pharmacogenetic testing in a large safety net health care system, we determined the number of patients taking targeted medications and their clinical care encounter sites. METHODS: Using 1-year electronic medical record data, we evaluated the number of patients who had started one or more of 30 known pharmacogenomically actionable medications and the number of care encounter sites the patients had visited. RESULTS: Results showed 7039 unique patients who started one or more of the target medications within a 12-month period with visits to 73 care sites within the system. CONCLUSION: Findings suggest that the type of large-scale, multi-drug, multi-gene approach to pharmacogenetic testing we are planning is widely relevant, and successful implementation will require wide-scale education of prescribers and other personnel involved in medication dispensing and handling.
Plasma and Intracellular Concentrations in HIV-infected Patients Requiring Hemodialysis Dosed with Tenofovir Disoproxil Fumarate and Emtricitabine
(Wolters Kluwer, 2016-09-01) Slaven, James E.; Decker, Brian S.; Kashuba, Angela D. M.; Atta, Mohamed G.; Wyatt, Christina M.; Gupta, Samir K.; Medicine, School of Medicine
Prediction of Nephropathy in Type 2 Diabetes: An Analysis of the ACCORD Trial Applying Machine Learning Techniques
(Wiley, 2019-09) Rodriguez‐Romero, Violeta; Bergstrom, Richard F.; Decker, Brian S.; Lahu, Gezim; Vakilynejad, Majid; Bies, Robert R.; Medicine, School of Medicine
Applying data mining and machine learning (ML) techniques to clinical data might identify predictive biomarkers for diabetic nephropathy (DN), a common complication of type 2 diabetes mellitus (T2DM). A retrospective analysis of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial was intended to identify such factors using ML. The longitudinal data were stratified by time after patient enrollment to differentiate early and late predictors. Our results showed that Random Forest and Simple Logistic Regression methods exhibited the best performance among the evaluated algorithms. Baseline values for glomerular filtration rate (GFR), urinary creatinine, urinary albumin, potassium, cholesterol, low-density lipoprotein, and urinary albumin to creatinine ratio were identified as DN predictors. Early predictors were the baseline values of GFR, systolic blood pressure, as well as fasting plasma glucose (FPG) and potassium at month 4. Changes per year in GFR, FPG, and triglycerides were recognized as predictors of late development. In conclusion, ML-based methods successfully identified predictive factors for DN among patients with T2DM.
Self-management interventions in stages 1 to 4 chronic kidney disease: an integrative review
(SAGE, 2015-05) Welch, Janet L.; Johnson, Michelle; Zimmerman, Lani; Russell, Cynthia L.; Perkins, Susan M.; Decker, Brian S.; IU School of Nursing
The prevalence, effect on health outcomes, and economic impact of chronic kidney disease (CKD) have created interest in self-management interventions to help slow disease progression to kidney failure. Seven studies were reviewed to identify knowledge gaps and future directions for research. All studies were published between 2010 and 2013; no investigations were conducted in the United States. Knowledge gaps included the focus on medical self-management tasks with no attention to role or emotional tasks, lack of family involvement during intervention delivery, and an inability to form conclusions about the efficacy of interventions because methodological rigor was insufficient. Educational content varied across studies. Strategies to improve self-management skills and enhance self-efficacy varied and were limited in scope. Further development and testing of theory-based interventions are warranted. There is a critical need for future research using well-designed trials with appropriately powered sample sizes, well-tested instruments, and clear and consistent reporting of results.

Browsing by Author "Decker, Brian S."

Results Per Page

Sort Options