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Veeravalli V, Cheruvu HS, Srivastava P, Vamsi Madgula LM. Three-dimensional aspects of formulation excipients in drug discovery: a critical assessment on orphan excipients, matrix effects and drug interactions. J Pharm Anal 2020; 10:522-531. [PMID: 33425449 PMCID: PMC7775846 DOI: 10.1016/j.jpha.2020.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/02/2020] [Accepted: 02/17/2020] [Indexed: 11/22/2022] Open
Abstract
Formulation/pharmaceutical excipients play a major role in formulating drug candidates, with the objectives of ease of administration, targeted delivery and complete availability. Many excipients used in pharmaceutical formulations are orphanized in preclinical drug discovery. These orphan excipients could enhance formulatability of highly lipophilic compounds. Additionally, they are safe in preclinical species when used below the LD50 values. However, when the excipients are used in formulating compounds with diverse physico-chemical properties, they pose challenges by modulating study results through their bioanalytical matrix effects. Excipients invariably present in study samples and not in the calibration curve standards cause over-/under- estimation of exposures. Thus, the mechanism by which excipients cause matrix effects and strategies to nullify these effects needs to be revisited. Furthermore, formulation excipients cause drug interactions by moderating the pathways of drug metabolizing enzymes and drug transport proteins. Although it is not possible to get rid of excipient driven interactions, it is always advised to be aware of these interactions and apply the knowledge to draw meaningful conclusions from study results. In this review, we will comprehensively discuss a) orphan excipients that have wider applications in preclinical formulations, b) bioanalytical matrix effects and possible approaches to mitigating these effects, and c) excipient driven drug interactions and strategies to alleviate the impacts of drug interactions.
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Affiliation(s)
- Vijayabhaskar Veeravalli
- Syngene International Limited, Biocon Park, SEZ, Bommasandra Industrial Area - Phase-IV Bommasandra-Jigani Link Road, Bangalore, 560099, India
| | - Hanumanth Srikanth Cheruvu
- Syngene International Limited, Biocon Park, SEZ, Bommasandra Industrial Area - Phase-IV Bommasandra-Jigani Link Road, Bangalore, 560099, India
| | | | - Lakshmi Mohan Vamsi Madgula
- Syngene International Limited, Biocon Park, SEZ, Bommasandra Industrial Area - Phase-IV Bommasandra-Jigani Link Road, Bangalore, 560099, India
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Patel V, Lalani R, Bardoliwala D, Ghosh S, Misra A. Lipid-Based Oral Formulation Strategies for Lipophilic Drugs. AAPS PharmSciTech 2018; 19:3609-3630. [PMID: 30255474 DOI: 10.1208/s12249-018-1188-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 09/14/2018] [Indexed: 01/22/2023] Open
Abstract
Partition coefficient (log P) is a key physicochemical characteristic of lipophilic drugs which plays a significant role in formulation development for oral administration. Lipid-based formulation strategies can increase lymphatic transport of these drugs and can enhance bioavailability many folds. The number of lipophilic drugs in pharmacopoeias and under discovery are continuously increasing and making the job of the formulation scientist difficult to develop suitable formulation of these drugs due to potent nature and water insolubility of these drugs. Recently, many natural and synthetic lipids are appearing in the market which are helpful in the development of lipid-based formulations of these types of drugs having enhanced solubility and bioavailability. One such reason for this enhanced bioavailability is the accessibility of the lymphatic transport as well as avoidance of first-pass effect. This review discusses the impact of lipophilicity in enhancing the intestinal lymphatic drug transport thereby reducing first-pass metabolism. The most appropriate strategy for developing a lipid-based formulation depending upon the degree of lipophilicity has been critically discussed and provides information on how to develop optimum formulation. Various formulation strategies are discussed in-depth by classifying lipid-based oral drug delivery systems with case studies of few marketed formulations with challenges and opportunities for the future of the formulations.
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Huang M, Wang HM, Guo Y, Ping J, Chen M, Xu D, Wang H. Single nucleotide polymorphism of CYP3A4 intron 2 and its influence on CYP3A4 mRNA expression and liver enzymatic activity in human liver. JOURNAL OF HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY. MEDICAL SCIENCES = HUA ZHONG KE JI DA XUE XUE BAO. YI XUE YING DE WEN BAN = HUAZHONG KEJI DAXUE XUEBAO. YIXUE YINGDEWEN BAN 2015. [PMID: 26223917 DOI: 10.1007/s11596-015-1460-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In adult liver, CYP3A4 plays an important role in the metabolism of a wide range of endogenous and exogenous compounds. To investigate whether there is a single nucleotide polymorphism (SNP) of CYP3A4 intron 2 in the liver and its effects on the mRNA expression and enzymatic activity of CYP3A4, genomic DNA was extracted from 96 liver tissue samples obtained from patients who had undergone liver surgery. An SNP of CYP3A4 intron 2 was identified by polymerase chain reaction (PCR)-single-strand confirmation polymorphism and DNA sequencing. The mRNA expression of CYP3A4 was determined by the fluorescence quantitative PCR technique. The enzymatic activity of CYP3A4 was measured using erythromycin and testosterone as probe substrates. Twelve patients were found to have the SNP/T4127G CYP3A4 within intron 2. The mRNA levels of CYP3A4 in wild-type and SNP/T4127G samples were 2.62±1.09 and 2.79±1.63, respectively (P>0.05). Erythromycin N-demethylase activity in wild-type and SNP/T4127G samples were 121.2±32.8 and 124.7±61.6 nmol·mg(-1)·min(-1), respectively (P>0.05). The activity of testosterone 6β-hydroxylase was significantly different between wild-type (648±173 pmol·mg(-1)·min(-1)) and SNP/T4127G samples (540±196 pmol·mg(-1)·min(-1); P<0.05). In conclusion, the SNP/T4127G of CYP3A4 intron 2 exists in the liver. This SNP does not affect the mRNA expression of CYP3A4 but significantly decreases the hepatic microsomal testosterone 6β-hydroxylase activity of CYP3A4. Furthermore, this study indicates that the appropriate selection of probe substrates is very important in studying the relationship between the genotype and phenotype of CYP3A4.
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Affiliation(s)
- Min Huang
- Department of Endocrinology, Hubei Integrative Chinese and Western Medicine Hospital, Wuhan, 430015, China
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China
| | - Han-Ming Wang
- Department of Endocrinology, Hubei Integrative Chinese and Western Medicine Hospital, Wuhan, 430015, China
| | - Yu Guo
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China
| | - Jie Ping
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China
| | - Man Chen
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China
| | - Dan Xu
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China
| | - Hui Wang
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, 430071, China.
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China.
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Konstandi M, Johnson EO, Lang MA. Consequences of psychophysiological stress on cytochrome P450-catalyzed drug metabolism. Neurosci Biobehav Rev 2014; 45:149-67. [DOI: 10.1016/j.neubiorev.2014.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/17/2014] [Accepted: 05/18/2014] [Indexed: 12/11/2022]
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Liu L, Cao B, Aa J, Zheng T, Shi J, Li M, Wang X, Zhao C, Xiao W, Yu X, Sun R, Gu R, Zhou J, Wu L, Hao G, Zhu X, Wang G. Prediction of the pharmacokinetic parameters of triptolide in rats based on endogenous molecules in pre-dose baseline serum. PLoS One 2012; 7:e43389. [PMID: 22912866 PMCID: PMC3422234 DOI: 10.1371/journal.pone.0043389] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 07/20/2012] [Indexed: 11/28/2022] Open
Abstract
Background Individual variances usually affect drug metabolism and disposition, and hence result in either ineffectiveness or toxicity of a drug. In addition to genetic polymorphism, the multiple confounding factors of lifestyles, such as dietary preferences, contribute partially to individual variances. However, the difficulty of quantifying individual diversity greatly challenges the realization of individualized drug therapy. This study aims at quantitative evaluating the association between individual variances and the pharmacokinetics. Methodology/Principal Findings Molecules in pre-dose baseline serum were profiled using gas chromatography mass spectrometry to represent the individual variances of the model rats provided with high fat diets (HFD), routine chows and calorie restricted (CR) chows. Triptolide and its metabolites were determined using high performance liquid chromatography mass spectrometry. Metabonomic and pharmacokinetic data revealed that rats treated with the varied diets had distinctly different metabolic patterns and showed differential Cmax values, AUC and drug metabolism after oral administration of triptolide. Rats with fatty chows had the lowest Cmax and AUC values and the highest percentage of triptolide metabolic transformation, while rats with CR chows had the highest Cmax and AUC values and the least percentage of triptolide transformation. Multivariate linear regression revealed that in baseline serum, the concentrations of creatinine and glutamic acid, which is the precursor of GSH, were linearly negatively correlated to Cmax and AUC values. The glutamic acid and creatinine in baseline serum were suggested as the potential markers to represent individual diversity and as predictors of the disposal and pharmacokinetics of triptolide. Conclusions/Significance These results highlight the robust potential of metabonomics in characterizing individual variances and identifying relevant markers that have the potential to facilitate individualized drug therapy.
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Affiliation(s)
- Linsheng Liu
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Bei Cao
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Jiye Aa
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
- * E-mail: (GW); (JA)
| | - Tian Zheng
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Jian Shi
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Mengjie Li
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Xinwen Wang
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Chunyan Zhao
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Wenjing Xiao
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Xiaoyi Yu
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Runbin Sun
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Rongrong Gu
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Jun Zhou
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Liang Wu
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Gang Hao
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Xuanxuan Zhu
- Jiangsu Provincial Hospital of Traditional Chinese Medicine, Nanjing, Jiangsu, China
| | - Guangji Wang
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
- * E-mail: (GW); (JA)
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Patel JP, Brocks DR. The effect of oral lipids and circulating lipoproteins on the metabolism of drugs. Expert Opin Drug Metab Toxicol 2009; 5:1385-98. [DOI: 10.1517/17425250903176439] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wasan KM. The biological functions of lipid excipients and the implications for pharmaceutical products development. J Pharm Sci 2009; 98:379-82. [PMID: 18484625 DOI: 10.1002/jps.21435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kishor M Wasan
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.
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van der Ven LT, van de Kuil T, Leonards PE, Slob W, Lilienthal H, Litens S, Herlin M, Håkansson H, Cantón RF, van den Berg M, Visser TJ, van Loveren H, Vos JG, Piersma AH. Endocrine effects of hexabromocyclododecane (HBCD) in a one-generation reproduction study in Wistar rats. Toxicol Lett 2009; 185:51-62. [DOI: 10.1016/j.toxlet.2008.12.003] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 11/28/2008] [Accepted: 12/01/2008] [Indexed: 11/28/2022]
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Chen M, Xu D, Hu XL, Wang H. Effects of liver fibrosis on verapamil pharmacokinetics in rats. Clin Exp Pharmacol Physiol 2007; 35:287-94. [PMID: 17973928 DOI: 10.1111/j.1440-1681.2007.04826.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
1. Liver fibrosis is the compensatory state of cirrhosis. In the long asymptomatic period, it is imperative to select a proper dosing regimen for drugs that are applicable to hepatic fibrosis owing to altered pharmacokinetics and bioavailability. The present study was designed to observe the changes in verapamil pharmacokinetics in rats with early liver fibrosis with respect to alterations in cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp). 2. A rat liver fibrosis model was successfully established using several inducers, including a high-fat diet, alcohol and carbon tetrachloride. After rats received a single intravenous or oral dose of verapamil (5 mg/kg), the plasma concentrations of verapamil were determined at scheduled time-points using HPLC. The activity of hepatic and small intestinal microsomal erythromycin N-demethylase (a marker for CYP3A) and the expression of small intestinal cyp3a and multidrug resistance (mdr) mRNA were compared between normal rats and rats with liver fibrosis. 3. The results showed that when verapamil was administered intravenously, the area under the curve (AUC), elimination half-life (T((1/2)(K10))) and mean residence time (MRT) increased significantly, whereas clearance (Cl) decreased, in rats with liver fibrosis compared with normal rats. After oral administration of verapamil, the AUC, (T((1/2)(K10))) and maximum concentration (C(max)) increased, Cl decreased and the absorption half-life (T((1/2)(K01))) and time to peak concentration (T(max)) were unchanged compared with normal rats. The oral bioavailability of verapamil was 32.9% in normal rats and 34.4% in rats with liver fibrosis. Furthermore, decreased CYP3A activity in the liver was accompanied by upregulated cyp3a9/18 and unchanged mdr mRNA in the small intestine compared with normal rats. Expression of cyp3a9/18 and mdr mRNA in the intestine was significantly inhibited by verapamil. 4. The results suggest that the lowered Cl and increased AUC of verapamil after intravenous and oral administration in rats with liver fibrosis were due to downregulation of CYP3A in the liver. The absorption rate of verapamil in rats with liver fibrosis was unchanged because mdr was unchanged and cyp3a was inhibited in the intestine by verapamil itself. There was no notable difference in oral bioavailability between normal rats and rats with liver fibrosis.
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Affiliation(s)
- Man Chen
- Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan, Hubei Province, China
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Guo Y, Wang H, Zhang C. ESTABLISHMENT OF RAT PRECISION-CUT FIBROTIC LIVER SLICE TECHNIQUE AND ITS APPLICATION IN VERAPAMIL METABOLISM. Clin Exp Pharmacol Physiol 2007; 34:406-13. [PMID: 17439408 DOI: 10.1111/j.1440-1681.2007.04582.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Liver fibrosis is the compensatory state of cirrhosis. In the long asymptomatic period, it is imperative to select a proper dosing regimen for drugs that are applicable to hepatic fibrosis. Otherwise, progressive deterioration to uncompensated cirrhosis may occur. The present study explored the characteristics of drug metabolism in fibrotic liver. 2. A rat precision-cut fibrotic liver slice (PCFLS) technique was established and the metabolism of verapamil was studied employing this technique. A rat hepatic fibrosis model was successfully induced integrating complex factors that included a high-fat diet, alcohol and CCl4. The PCFLS were incubated under different conditions and lactate dehydrogenase leakage, glutathione S-transferase activity and 3[4,5-dimethythiazole-2-yl]-2,5-diphenyltetrazolium bromide reduction were used as indices to assess PCFLS viability. Activities of phase I and phase II metabolizing enzymes were monitored following treatment with cytochrome P450 (CYP) inducers. Normal and fibrotic liver slices were incubated individually with 10 micromol/L verapamil. The concentration of verapamil in the medium was determined by high-performance liquid chromatography and intrinsic clearance (Cl(int)) was calculated on the basis of the concentration-time curve. 3. The results showed that the PCFLS viability remained steady throughout the 6 h of culture when the thickness of slices was 300 microm and pH of the medium was 7.0; CYP inducers (phenobarbital and ethanol) enhanced CYP2E1, CYP3A1/2 and uridine diphosphate-glucuronate transferase (UDPGT) activities, respectively, in a time-dependent manner. The Cl(int) (microL/min per mg) values differed significantly between normal (9.7 +/- 1.8) and fibrotic (5.6 +/- 1.4) liver slices (P < 0.01). 4. These results suggested that the PCFLS could remain viable for 2-6 h under appropriate conditions. The stability and inducibility of drug-metabolizing enzymes of PCFLS were also demonstrated. Furthermore, the metabolic rate of verapamil in PCFLS was decreased. These findings add further support to the use of PCFLS as a tool to study drug metabolism and to guide clinical medication.
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Affiliation(s)
- Yu Guo
- Department of Pharmacology, Basic Medical College of Wuhan University, Wuhan, Hubei Province, China
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Wu D, Cederbaum A. Nitric oxide donors prevent while the nitric oxide synthase inhibitor l-NAME increases arachidonic acid plus CYP2E1-dependent toxicity. Toxicol Appl Pharmacol 2006; 216:282-92. [PMID: 16938321 DOI: 10.1016/j.taap.2006.05.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 05/16/2006] [Accepted: 05/19/2006] [Indexed: 01/23/2023]
Abstract
Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N(G)-Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48+/-6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23+/-5%, while, SNAP or DETA-NONO increased viability to 66+/-8 or 71+/-6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA-induced oxidative stress and toxicity. These results indicate that NO can be hepatoprotective against CYP2E1-dependent toxicity, preventing AA-induced oxidative stress.
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Affiliation(s)
- Defeng Wu
- Department of Pharmacology and Biological Chemistry, Box 1603, One Gustave L. Levy Place, Mount Sinai School of Medicine, New York, NY 10029, USA
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Howard CB, Samuel J, Henderson SB, Stevens J, Thomas PE, Cuchens MA. Effects of pristane on cytochrome P450 isozyme expression in rat tissues. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2006; 2:138-46. [PMID: 16708425 PMCID: PMC3814708 DOI: 10.3390/ijerph2005010138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chemical carcinogenesis studies are powerful tools to obtain information on potential mechanisms of chemical factors for malignancies. In this study Western blot analyses, using monoclonal antibodies specific for three different cytochrome P450 (CYP) isozymes (CYP1A1, CYP1A2 and CYP2B), were employed to examine the effect(s) of 3-methylcholanthrene and/or pristane (2,6,10,14-tetramethylpentadecane) on the basal and inducible levels of expression of CYP proteins within Copenhagen rat tissues. Pristane exposure led to tissue specific differences in the CYP isozymes expressed and elicited increased CYP protein expression over 3-methylcholanthrene induced levels in microsomes isolated from liver, Peyer’s Patches, and thymus. Within the context of the chemical carcinogenesis model employed in this study, these observations correlated with the induction of B-cell malignancies by low doses of 3-methylcholanthrene and of thymic lymphomas by a high 3-methylcholanthrene dose. The data suggest that pristane treatment affects CYP isozyme expression. This pristane-mediated effect clearly could be a contributing factor in the chemical carcinogenesis of the previously observed lymphoid malignancies, and a possible basis for the tumor enhancing effects of pristane.
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Affiliation(s)
- Carolyn B Howard
- Breast Cancer Research Laboratory, Department of Biology, and NIH-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, Jackson, Mississippi, USA.
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Rahman KM, Sugie S, Tanaka T, Mori H, Reddy BS. Effect of types and amount of dietary fat during the initiation phase of hepatocarcinogenesis. Nutr Cancer 2002; 39:220-5. [PMID: 11759284 DOI: 10.1207/s15327914nc392_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The effects of various levels of corn oil and lard fed during the initiation stage of azoxymethane (AOM)-induced hepatocarcinogenesis were studied in male Fischer 344 rats. The animals were fed diets containing 5%, 13.6%, and 23.5% corn oil or lard two weeks before, during, and until one week after injections of AOM (15 mg/kg body wt s.c.) once weekly for two weeks. One week after AOM treatment, groups of animals fed the 13.6% and 23.5% corn oil or lard diet were transferred to their respective 5% corn oil or lard diet and fed these diets until the termination of the study (34 wk). Immunohistochemical staining of glutathione S-transferase placental form was performed in the liver, and the number of glutathione S-transferase placental form-positive foci was determined. Density, average area, and unit area of foci were significantly inhibited in the animals fed the 13.6% and 23.5% lard diets compared with those fed the 13.6% and 23.5% corn oil diets. These results indicate that the effect of dietary fat during the initiation phase of AOM-induced hepatocarcinogenesis depends on the type of fat and its fatty acid composition. Additionally, the enhancing effect of a corn oil diet in hepatocarcinogenesis is mainly present during the initiation phase of carcinogenesis compared with a lard diet.
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Affiliation(s)
- K M Rahman
- Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Bai S, Brunner LJ, Stepkowski SM, Napoli KL, Kahan BD. Effect of low dose cyclosporine and sirolimus on hepatic drug metabolism in the rat1. Transplantation 2001; 71:1585-92. [PMID: 11435969 DOI: 10.1097/00007890-200106150-00017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND We examined the effect cyclosporine (CsA) and sirolimus (SRL) alone and in combination on hepatic cytochrome P450-mediated metabolism in rats. METHODS Rats were given 1 mg/kg of CsA or 0.4 mg/kg of SRL alone or in combination via constant intravenous infusion. Renal function was evaluated at the end of treatment. Blood samples were obtained to estimate CsA and SRL concentrations. Hepatic microsomes were prepared for immunoblotting and catalytic assays. RESULTS CsA alone did not alter serum creatinine levels. SRL given alone or in combination with CsA produced a significant increase in urine output without changes in fluid balance. Although CsA and SRL administered alone caused damage to renal proximal tubules, the two-drug combination dramatically increased the renal structural damage. CsA alone suppressed cytochrome P450 (CYP) 3A2 protein levels by 39% (P=0.012) and catalytic activity by 30% (P=0.042). SRL alone reduced catalytic activity by 38% (P=0.012). Combination therapy reduced both CYP3A2 levels by 55% (P<0.001) and catalytic activity by 55% (P=0.001). CYP2C11 protein expression or catalytic activity were not changed in any group. CYP2A1 protein expression and catalytic activity were both significantly reduced in rats given CsA or/and SRL. Steady-state CsA levels were increased during concurrent SRL dosing, however, SRL concentrations were not changed by CsA coadministration. CONCLUSIONS Concurrent SRL dosing increases CsA concentrations due to inhibition of hepatic CYP3A2 protein expression. Nephrotoxicity caused by combination therapy is due to CsA elevating levels of SRL or by SRL itself. Concurrent administration of CsA and SRL in transplant patients should be performed with caution.
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Affiliation(s)
- S Bai
- 4 Address correspondence to: Lane J. Brunner, Ph.D., Pharmaceutics Division, PHR 4.214E, College of Pharmacy, The University of Texas at Austin, Austin, TX, 78712-1074
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Chen HW, Yang JJ, Tsai CW, Wu JJ, Sheen LY, Ou CC, Lii CK. Dietary fat and garlic oil independently regulate hepatic cytochrome p(450) 2B1 and the placental form of glutathione S-transferase expression in rats. J Nutr 2001; 131:1438-43. [PMID: 11340096 DOI: 10.1093/jn/131.5.1438] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The individual and combined effects of dietary fat and garlic oil on two drug-metabolizing enzymes, cytochrome P(450) 2B1 and the placental form of glutathione (GSH) S-transferase (PGST), in rat liver were examined in this study. Rats were fed a low corn oil, high corn oil or high fish oil diet and received various amount of garlic oil (0, 30, 80, 200 mg/kg body) orally three times per week for 6 wk. The fat energy in the low and high fat diets accounted for 11.6 and 45.7% of total energy, respectively. Final body weights did not differ among the three dietary fat groups and were not affected by garlic oil treatment. The fatty acid profile in hepatic phospholipids revealed higher eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] levels in the fish oil-fed group than in the low and high corn oil-fed groups (P < 0.05). In contrast, the corn oil-fed groups had greater hepatic phospholipid arachidonic acid [20:4(n-6)] levels (P < 0.05). Both dietary fat and garlic oil significantly affected hepatic cytochrome 7-pentoxyresorufin O-dealkylase (PROD) activity and GST activity toward ethacrynic acid. Rats fed the high fish oil diet had 85 and 51% higher PROD activity compared with those fed the low or the high corn oil diet, respectively (P < 0.05). The GST activity in the high fish oil and the high corn oil groups was 33 and 18% higher than that in the low corn oil group (P < 0.05), respectively, and the GST activity in rats fed the high fish oil diet was higher than in those fed the high corn oil diet (P < 0.05). Garlic oil dose-dependently increased GST activity. No interaction between dietary fat and garlic oil on PROD or GST activity was noted. Northern and Western blot analysis revealed that dietary fish oil increased both cytochrome P(450) 2B1 and PGST mRNA and protein levels. Cytochrome P(450) 2B1 and PGST mRNA and protein levels were also dose-dependently increased by garlic oil treatment. The effects of garlic oil and dietary fat on P(450) 2B1 and PGST mRNA and protein expression were independent. These results indicate that dietary fat and garlic oil independently modulate P(450) 2B1 and PGST expression at transcriptional and/or post-transcriptional stages.
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Affiliation(s)
- H W Chen
- Department of Nutrition, Chung Shan Medical College, National Chung Cheng University, Min-Hsiung 621, Taiwan
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16
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Wasan KM. Formulation and physiological and biopharmaceutical issues in the development of oral lipid-based drug delivery systems. Drug Dev Ind Pharm 2001; 27:267-76. [PMID: 11411894 DOI: 10.1081/ddc-100103726] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The rapidly increasing availability of drug receptor structural characteristics has permitted the receptor-guided synthesis of potential new drug molecules. This synthesis strategy frequently results in the creation of polycyclic and highly hydrophobic compounds, with attendant poor oral bioavailability resulting from low solubility and slow dissolution rate in the primarily aqueous contents of the gastrointestinal (GI) tract. In an attempt to improve the solubility-limited bioavailabiliy associated with these compounds, formulators have turned to the use of lipid excipients in which the compounds can be solubilized prior to oral administration. This new class of excipients presents the pharmaceutical scientist with a number of new challenges at all stages of the formulation development process, beginning with the excipient selection and stability assessment of the prototype formulation, up to and including scale-up and mass production of the final market-image product. The interaction of lipid-based formulations with the gastrointestinal system and associated digestive processes presents additional challenges and opportunities that will be understood more fully as we begin to unravel the intricacies of the GI processing of lipid excipients. For example, an increasing body of evidence has shown that certain lipids are capable of inhibiting both presystemic drug metabolism and drug efflux by the gut wall mediated by p-glycoprotein (PGP). And, it is well known that lipids are capable of enhancing lymphatic transport of hydrophobic drugs, thereby reducing drug clearance resulting from hepatic first-pass metabolism. This review addresses the current state of knowledge regarding oral lipid-based formulation development and scale-up issues and the physiological and biopharmaceutical aspects pertinent to the development of an orally bioavailable and efficacious dosage form.
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Affiliation(s)
- K M Wasan
- Division of Pharmaceutics and Biopharmaceutics, Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada.
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Maguire PJ, Fettman MJ, Smith MO, Greco DS, Turner AS, Walton JA, Ogilvie GK. Effects of diet on pharmacokinetics of phenobarbital in healthy dogs. J Am Vet Med Assoc 2000; 217:847-52. [PMID: 10997154 DOI: 10.2460/javma.2000.217.847] [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: 11/20/2022]
Abstract
OBJECTIVE To determine effects of various diets on the pharmacokinetics of phenobarbital and the interactive effects of changes in body composition and metabolic rate. DESIGN Prospective study. ANIMALS 27 healthy sexually intact adult female Beagles. PROCEDURE Pharmacokinetic studies of phenobarbital were performed before and 2 months after dogs were fed 1 of 3 diets (group 1, maintenance diet; group 2, protein-restricted diet; group 3, fat- and protein-restricted diet) and treated with phenobarbital (approx 3 mg/kg [1.4 mg/lb] of body weight, p.o., q 12 h). Pharmacokinetic studies involved administering phenobarbital (15 mg/kg [6.8 mg/lb], i.v.) and collecting blood samples at specific intervals for 240 hours. Effects of diet and time were determined by repeated-measures ANOVA. RESULTS Volume of distribution, mean residence time, and half-life (t1/2) of phenobarbital significantly decreased, whereas clearance rate and elimination rate significantly increased with time in all groups. Dietary protein or fat restriction induced significantly greater changes: t1/2 (hours) was lower in groups 2 (mean +/- SD; 25.9 +/- 6.10 hours) and 3 (24.0 +/- 4.70) than in group 1 (32.9 +/- 5.20). Phenobarbital clearance rate (ml/kg/min) was significantly higher in group 3 (0.22 +/- 0.05 ml/kg/min) than in groups 1 (0.17 +/- 0.03) or 2 (0.18 +/- 0.03). Induction of serum alkaline phosphatase activity (U/L) was greater in groups 2 (192.4 +/- 47.5 U/L) and 3 (202.0 +/- 98.2) than in group 1 (125.0 +/- 47.5). CONCLUSIONS AND CLINICAL RELEVANCE Clinically important differences between diet groups were observed regarding pharmacokinetics of phenobarbital, changes in CBC and serum biochemical variables, and body composition. Drug dosage must be reevaluated if a dog's diet, body weight, or body composition changes during treatment. Changes in blood variables that may indicate liver toxicosis caused by phenobarbital may be amplified by diet-drug interactions.
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Affiliation(s)
- P J Maguire
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA
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19
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Rahman KM, Sugie S, Okamoto K, Watanabe T, Tanaka T, Mori H. Modulating effects of diets high in omega-3 and omega-6 fatty acids in initiation and postinitiation stages of diethylnitrosamine-induced hepatocarcinogenesis in rats. Jpn J Cancer Res 1999; 90:31-9. [PMID: 10076562 PMCID: PMC5925980 DOI: 10.1111/j.1349-7006.1999.tb00662.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The effects of sardine fish oil or corn oil on diethylnitrosamine (DEN)-induced hepatocarcinogenesis were investigated in male F344 rats. Starting at 5 weeks of age, animals were divided into 11 groups and fed 23.5% corn oil (HCO) (groups 1 and 7) or 5% corn oil (LCO) (groups 2 and 8), 22.5% sardine oil + 1% corn oil (FO) semipurified diet (groups 3 and 9) or basal diet (CE-2) (groups 4-6, 10 and 11). At 6 weeks of age, all animals except the vehicle-treated groups were given DEN (200 mg/kg body weight, i.p. once weekly for 3 weeks). One week after the final exposure to DEN, groups 1-3 were changed to the basal diet, and groups 4-6 were switched to the HCO, LCO or FO diet, respectively. Animals in groups 1-3 and 10 were given drinking water containing 0.05% phenobarbital (PB). Liver sections from the animals at the termination of the experiment (24 weeks) were doubly stained for glutathione S-transferase placental form (GST-P) and silver-stained nucleolar organizer regions (AgNORs). The multiplicity of hepatocellular neoplasms of group 1 was significantly larger than that of group 2 or 3. The number of GST-P-positive foci of group 2 or 3 was significantly smaller than that of group 1. Among the groups fed the experimental diets in the postinitiation phase (groups 4-6), no significant difference was found in the incidence of liver tumors. AgNORs values of the enzyme-altered foci in rats of the HCO diet groups were larger than those of the other diet groups. These results indicate that the enhancing effect of a high dose of corn oil in hepatocarcinogenesis is mainly present during the initiation phase but not during postinitiation phase, and fish oil rich in polyunsaturated omega-3 fatty acids could inhibit DEN-induced hepatocarcinogenesis in rats.
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MESH Headings
- Animals
- Biomarkers, Tumor/analysis
- Body Weight/drug effects
- Carcinogens/toxicity
- Corn Oil
- Diet, Fat-Restricted
- Dietary Fats, Unsaturated
- Diethylnitrosamine/toxicity
- Fatty Acids, Omega-3/pharmacology
- Fatty Acids, Omega-6
- Fatty Acids, Unsaturated/pharmacology
- Fish Oils
- Glutathione Transferase/analysis
- Liver/drug effects
- Liver/enzymology
- Liver/pathology
- Liver Neoplasms, Experimental/chemically induced
- Liver Neoplasms, Experimental/pathology
- Liver Neoplasms, Experimental/prevention & control
- Male
- Organ Size/drug effects
- Rats
- Rats, Inbred F344
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Affiliation(s)
- K M Rahman
- Department of Pathology, Gifu University School of Medicine
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20
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Rijnkels JM, Delsing DB, van der Reijden AC, Alink GM. Effects of vegetables-fruit extracts and indole-3-carbinol on stearic acid-modulated intercellular communication and cytochrome P450-IA activity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 1998; 6:103-109. [PMID: 21781886 DOI: 10.1016/s1382-6689(98)00024-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/1997] [Revised: 05/06/1998] [Accepted: 05/13/1998] [Indexed: 05/31/2023]
Abstract
Modulatory effects were investigated of extracts of a vegetables-fruit mixture and indole-3-carbinol (I3C) on stearic acid-modulated gap junctional intercellular communication (GJIC) and cytochrome P450-IA activity (EROD). In V79 cells, pure water and hexane extracts of a vegetables-fruit mixture and 25 μg/ml I3C significantly protected against decreased GJIC caused by 10 μM stearic acid. Furthermore, pure, 10× and 100× diluted vegetables-fruit extracts significantly maintained their capacity to induce EROD activity in Caco-2 cells, but only when these extracts were added to the cells in media already containing 500 μM stearic acid for 48 h. Stearic acid itself did not induce EROD activity. I3C (10, 25, and 50 μg/ml) clearly induced EROD activity in Caco-2 cells, irrespective of the order at which I3C and stearic acid were added to the cells. In conclusion, the present in vitro study showed that vegetables-fruit extracts and I3C modulate effects of stearic acid on intercellular communication and cytochrome P450-IA activity.
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Affiliation(s)
- J M Rijnkels
- Department of Toxicology, Agricultural University Wageningen, Tuinlaan 5, 6703 HE Wageningen, The Netherlands
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21
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Arévalo JC, Pérez-González MN, Sánchez-Bernal C, Llanillo M. Phospholipid fatty acid and lipid peroxidation in liver microsomes from guinea pigs fed oil related to the toxic oil syndrome. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1998; 120:111-9. [PMID: 9827023 DOI: 10.1016/s0742-8413(98)00031-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The potential effects of oil specimens both related and unrelated to cases of Toxic Oil Syndrome (TOS) on the phospholipid fatty acid composition, some antioxidant enzyme activities, and lipid peroxidation in guinea pig liver microsomes were investigated. For 4 weeks, animals were fed diets supplemented with either oil related to cases of TOS or control oil, previously heated or not. In all cases, the fat diet produced the incorporation of approximately 7% of linoleic acid exclusively in the phosphatidylethanolamine (PE) of liver microsomes. A pronounced increase in lipid peroxidation products, measured as malondialdehyde (MDA) and 4-hydroxyalkenals, was detected in animals fed nonheated control oil. Heated oil diets produced significant increases in superoxide dismutase and glutathione peroxidase activities with concomitant decreases in the lipid peroxidation status. Heated oils also increased the oleic/stearic acid ratio in the phosphatidylserine plus phosphatidylinositol (PS + PI) fraction. This ratio was also increased in the same fraction from animals fed non heated case oil. The study shows that case oil produces a decrease in the lipid peroxidation products with minimal alterations in phospholipid fatty acid composition of liver microsomes, which is dependent rather on the composition of dietary fat than on toxic effects.
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Affiliation(s)
- J C Arévalo
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Spain
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22
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Chen HW, Lii CK, Wu MH, Ou CC, Sheen LY. Amount and type of dietary lipid modulate rat hepatic cytochrome P-450 activity. Nutr Cancer 1998; 29:174-80. [PMID: 9427983 DOI: 10.1080/01635589709514621] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The influence of the amount and type of dietary lipid on rat hepatic cytochrome P-450 activities in the presence and absence of inducer administration was investigated. Weanling male Sprague-Dawley rats were fed fat-free or 20% beef tallow, olive oil, corn oil, linseed oil, or menhaden oil diets in combination with one of the following three treatments: no inducer, intraperitoneal injection of phenobarbital (75 mg/kg body wt) for three consecutive days before they were killed, or intragastric administration of acetone (5 ml/kg) one day before they were killed. Twenty percent linseed oil and menhaden oil diets induced the highest level of activity among the different fat types in the presence of phenobarbital and acetone. Cytochrome P-450IIB1 activity was induced to a significantly greater extent by acetone administration in conjunction with the 20% menhaden oil diet than in conjunction with the other dietary oils (p < 0.05). In the presence of acetone, 20% beef tallow, 20% linseed oil, and 20% menhaden oil diets significantly induced cytochrome P-450IIE1 activity compared with the fat-free diet (p < 0.05). In conclusion, cytochrome P-450IIB1 and P-450IIE1 activities in rats were significantly increased by specific inducers, and dietary lipid was necessary for this effect. Diets supplemented with linseed and menhaden oils were most effective in inducing this activity.
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Affiliation(s)
- H W Chen
- Department of Nutrition, Chung Shan Medical College, Taichung, Taiwan
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23
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Shao Y, Pardini L, Pardini RS. Intervention of transplantable human mammary carcinoma MX-1 chemotherapy with dietary menhaden oil in athymic mice: increased therapeutic effects and decreased toxicity of cyclophosphamide. Nutr Cancer 1997; 28:63-73. [PMID: 9200152 DOI: 10.1080/01635589709514554] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated the effects of dietary menhaden oil on cyclophosphamide (CP) antineoplastic activity and its protective effect against CP toxicity. We found that dietary menhaden oil (HMO, 20% menhaden oil + 5% corn oil) enhanced the CP antitumor effect at the lowest dose tested (50 mg/kg) compared with the control group (LCO, 5% corn oil). Dietary HMO and CP treatment had a significant effect on the activities of tumor and liver microsomal cytochrome P-450 (CYP) over the controls. Activity of one of the key CP activating enzymes, CYP2B1 (which is similar to human CYP2B6), was significantly enhanced in the liver and tumor by the HMO diet, which could result in the formation of more pharmacologically active CP metabolites and, therefore, increased CP antitumor response. Moreover, the HMO diet exhibited a very significant protective effect against CP acute toxicity. The activity of the CP detoxifying enzyme aldehyde dehydrogenase (ADH) was significantly increased in the liver after HMO feeding; thus the observed protective effect of HMO feeding against CP toxicity may be partially the result of induction of ADH activity in the liver. In summary, our findings suggested that dietary menhaden oil can modulate ADH and CYP activities in a manner that may alter the metabolism of CP and, therefore, improve its therapeutic index by increasing its therapeutic effect and decreasing its toxicity.
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Affiliation(s)
- Y Shao
- Allie M. Lee Laboratory for Cancer Research, Department of Biochemistry, University of Nevada, Reno 89557, USA
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24
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Kojo A, Pellinen P, Juvonen R, Raunio H, Pelkonen O, Pasanen M. Distinct responses of mouse hepatic CYP enzymes to corn oil and peroxisome proliferators. Biochem Pharmacol 1996; 51:1137-43. [PMID: 8645335 DOI: 10.1016/0006-2952(96)00027-5] [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 studied the response of male DBA/2N mouse liver monooxygenases to acute (one-day) and subacute (7-day) exposure to clofibrate, gemfibrozil, and corn oil. The day following a single treatment with clofibrate (200 mg/kg), coumarin 7-hydroxylase (COH) activity decreased significantly (by 70%) with a concomitant decrease in the CYP2A4/5 protein and mRNA levels. The 7-day treatment schedule also decreased COH activity by only by 30%, though the levels of CYP2A4/5 protein and mRNA were still low. Treatment 1 and 7-day with clofibrate decreased 7-pentoxyresorufin O-dealkylase (PROD) activity by 40%. No changes were seen in testosterone 15 alpha-hydroxylase (T15 alpha OH) activity after 1 day of treatment with clofibrate but, after 7 days, it was decreased by 50%. Clofibrate treatment had no significant effects on testosterone 7 alpha-hydroxylase (T7 alpha OH), 7-ethoxyresorufin O-deethylase (EROD), or benzphetamine N-demethylase (BZDM) activities. Gemfibrozil (200 mg/kg) did not alter COH activity or CYP2A4/5 protein content after a single treatment, but a slight decrease was seen in the mRNA level. Treatment for 7 days significantly increased (2.5-fold) the activity and mRNA content but the amount of protein remained unchanged. Gemfibrozil enhanced (2-2.7-fold PROD and EROD (2-2.5-fold) activities by both treatments, whereas T15 alpha OH, T7 alpha OH, or BZDM activities were not significantly affected. Treatment with corn oil for 7 days significantly decreased (65%) COH activity and CYP2A4/5 protein and mRNA levels. PROD (55%) and T15 alpha OH (65%) activities were significantly decreased even after a single dose although injection for 7 days had no effect. Neither of the corn oil schedules had any marked effect on T7 alpha OH, EROD, or BZDM activities. These results demonstrate: 1. a decrease in the expression of CYP2A4/5 gene by clofibrate and corn oil; 2. substantial differences within the CYP2A subfamily in their responses to corn oil, clofibrate, and gemfibrozil; and 3. distinct responses of other xenobiotic metabolizing CYP subfamily enzymes to clofibrate and gemfibrozil.
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Affiliation(s)
- A Kojo
- Department of Pharmacology and Toxicology, University of Kuopio, Finland
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25
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Affiliation(s)
- W M Lee
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-8887, USA
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26
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de la Casa E, Pérez-González N, Sánchez-Bernal C, Llanillo M. Effects of dietary oil related to the toxic oil syndrome on the lipids of guinea pig liver microsomes. Lipids 1995; 30:575-9. [PMID: 7651086 DOI: 10.1007/bf02537033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The potential effects of oil specimens related to cases of toxic oil syndrome (TOS) on the liver microsomal lipid composition from guinea pigs were investigated. For four weeks, animals were fed diets supplemented with either "case oil" (oil related to cases of TOS) or "control oil" (oil unrelated to cases of TOS), either previously heated or not. Results were compared with those from guinea pigs fed the same diet with no oil. The administration of case oil produced changes in liver microsomal lipid composition. Statistically significant differences were also found between heated case and heated control oils. The cholesterol/phospholipid molar ratios and the major phospholipid class distribution were unaffected under these diet conditions. However, increases in the relative contents of linoleic and arachidonic acids and, simultaneously, a reduction in palmitic and palmitoleic acid levels were observed by diet effects. Heated oil administration decreased the saturated/unsaturated ratios in all cases. Our data suggest that changes observed in the fatty acid composition are attributable to the free fatty acid contents of administered oils. The toxic constituents of case oil seem to be able to alter the liver microsomal lipid composition.
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Affiliation(s)
- E de la Casa
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Spain
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27
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Abstract
The aflatoxins are a group of closely related mycotoxins that are widely distributed in nature. The most important of the group is aflatoxin B1 (AFB1), which has a range of biological activities, including acute toxicity, teratogenicity, mutagenicity and carcinogenicity. In order for AFB1 to exert its effects, it must be converted to its reactive epoxide by the action of the mixed function mono-oxygenase enzyme systems (cytochrome P450-dependent) in the tissues (in particular, the liver) of the affected animal. This epoxide is highly reactive and can form derivatives with several cellular macromolecules, including DNA, RNA and protein. Cytochrome P450 enzymes may additionally catalyse the hydroxylation (to AFQ1 and AFM1) and demethylation (to AFP1) of the parent AFB1 molecule, resulting in products less toxic than AFB1. Conjugation of AFB1 to glutathione (mediated by glutathione S-transferase) and its subsequent excretion is regarded as an important detoxification pathway in animals. Resistance to AFB1 toxicity has been interpreted in terms of levels and activities of these detoxifying pathways. This article reviews the multiple reactions and effects attributed to aflatoxin, with particular reference to the interaction of aflatoxin with nucleic acids and proteins, and the contribution this mycotoxin has in disease development and in the promotion of hepatocellular carcinoma (HCC). The anti-mutagenic properties of several dietary factors are also considered in this article. Undoubtedly, the most important aspect of aflatoxin action is its putative role in the development of human cancer, in particular, HCC. Recently, there has been a renewed interest in this aspect and experimental evidence is rapidly accumulating at the molecular level, indicating aflatoxin as an important consideration in the aetiology of human HCC.
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Affiliation(s)
- M McLean
- Department of Physiology, Faculty of Medicine, University of Natal, Congella, Durban, South Africa
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Earl-Salotti GI, Charland SL. The effect of parenteral nutrition on hepatic cytochrome P-450. JPEN J Parenter Enteral Nutr 1994; 18:458-65. [PMID: 7815680 DOI: 10.1177/0148607194018005458] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Total parenteral nutrition (TPN) has been shown to affect liver function tests. Additional investigations in animals and humans have demonstrated that hepatic cytochrome P-450 content and enzyme activity are also affected. METHODS To review the literature on the effect of TPN on hepatic cytochrome P-450, an English-language literature search was performed using MEDLINE (1966 through 1993). RESULTS Studies in laboratory rats show that administration of dextrose, with or without amino acids, decreases the cytochrome P-450 content and the in vitro or in vivo microsomal oxidation rates of various drugs. The addition of lipid emulsions to TPN decreases oxidation rates for meperidine demethylase but does not affect ethoxyresorufin deethylase. Using immunoquantitation, it was shown that the components of TPN selectively affect specific hepatic P-450 enzymes. In humans, dextrose decreases antipyrine clearance, whereas amino acids and possibly lipids increase antipyrine clearance. However, the effects of protein-calorie malnutrition in these studies obscure the results. CONCLUSIONS Possible mechanisms for the reduction of hepatic cytochrome P-450 seen during TPN administration include altered gastrointestinal hormone response, mucosal barrier, and the effect of sepsis. Additional studies are needed to determine the actual mechanisms of hepatic cytochrome P-450 reduction observed during TPN.
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Affiliation(s)
- G I Earl-Salotti
- Department of Pharmacy Practice and Administration, Philadelphia College of Pharmacy and Science
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29
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Sequeira DJ, Cawley GF, Eyer CS, Backes WL. Temporal changes in P-450 2E1 expression with continued ethylbenzene exposure. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1207:179-86. [PMID: 8075152 DOI: 10.1016/0167-4838(94)00070-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The goal of this study was to examine the effect of duration of ethylbenzene exposure on cytochrome P-450-dependent activities. Male rats were treated with ethylbenzene by intraperitoneal injection for either 1 or 3 days, and microsomal preparations were examined for changes in the microsomal proteins and activities as well as the expression of specific P-450 isozymes. Two general patterns of induction were evident when different P-450-dependent activities were examined. (i) Cytochrome P-450 2B-dependent activities (e.g., p-nitroanisole demethylation, benzphetamine demethylation, and aromatic toluene hydroxylations) were induced both after 1 and 3 days of ethylbenzene exposure. (ii) Cytochrome P-450 2E1-dependent activities (e.g., N,N-dimethylnitrosamine demethylation and aniline hydroxylation) were induced after treatment with ethylbenzene for one day; however, after 3 days of ethylbenzene treatment these activities returned to control levels. Changes in these activities were consistent with changes in the levels of specific P-450 isozymes as determined by immunoblotting. Cytochrome P-450 2B levels were increased and P-450 2C11 levels were suppressed at both 1 and 3 days of ethylbenzene exposure. A temporal response in P-450 2E1 expression was observed, with P-450 2E1 levels increasing after a single ethylbenzene injection and returning to controls after administration of the hydrocarbon for 3 days. Rats were also subjected to a pair-feeding regimen to determine whether these effects were related to altered dietary status in ethylbenzene-treated rats. Neither P-450-dependent activities nor immunoreactive protein levels were altered in pair-fed rats. These results demonstrate that prolonging the duration of hydrocarbon exposure can produce differential effects on the expression of P-450 2E1, with levels being elevated after acute hydrocarbon administration, but not after more prolonged hydrocarbon exposure.
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Affiliation(s)
- D J Sequeira
- Department of Pharmacology, Louisiana State, University Medical Center, New Orleans 70112
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30
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Affiliation(s)
- D V Parke
- School of Biological Sciences, University of Surrey, Guildford, U.K
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31
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Dannenberg AJ, Yang EK, Aharon D. Dietary lipids induce phase 2 enzymes in rat small intestine. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1210:8-12. [PMID: 8257722 DOI: 10.1016/0005-2760(93)90042-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We examined the role of dietary lipids in determining the activities of glutathione S-transferase (GST) and UDPglucuronosyl-transferase (UGT) in rat small intestine. Male Wistar rats were fed a fat-free (FF) diet or isocaloric control diet containing 5% corn oil (CO) or 5% fish oil (FO) for 3 weeks. The activities of these enzymes were about 2-fold higher in rats fed the FO diet vs. the FF diet. Intermediate levels of enzyme activity were found in rats fed the CO diet. Diet-induced differences in enzyme levels were shown by immunoblotting. The highest levels of glutathione S-transferase and UDPglucuronosyltransferase were detected in rats fed the FO diet. The lowest levels of these enzymes were found in rats fed the FF diet. Intermediate levels of enzyme were detected in rats fed the CO diet. Thus, diet-induced differences in enzyme activities were paralleled by changes in enzyme levels. Fatty acid analysis of mucosal lipids showed that the FF and FO diets were associated with decreased levels of linoleic and arachidonic acids as compared with the CO diet.
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Affiliation(s)
- A J Dannenberg
- Department of Medicine, Cornell University Medical College, New York
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Manjgaladze M, Chen S, Frame LT, Seng JE, Duffy PH, Feuers RJ, Hart RW, Leakey JE. Effects of caloric restriction on rodent drug and carcinogen metabolizing enzymes: implications for mutagenesis and cancer. Mutat Res 1993; 295:201-22. [PMID: 7507558 DOI: 10.1016/0921-8734(93)90021-t] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Caloric restriction in rodents results in increased longevity and a decreased rate of spontaneous and chemically induced neoplasia. The low rates of spontaneous neoplasia and other pathologies have made calorically restricted rodents attractive for use in chronic bioassays. However, caloric restriction also alters hepatic drug metabolizing enzyme (DME) expression and so may also alter the biotransformation rates of test chemicals. These alterations in DME expression may be divided into two types: (1) those that are the direct result of caloric restriction itself and are detectable from shortly after the restriction is initiated; (2) those which are the result of pathological conditions that are delayed by caloric restriction. These latter alterations do not usually become apparent until late in the life of the organism. In rats, the largest direct effect of caloric restriction on liver DMEs is an apparent de-differentiation of sex-specific enzyme expression. This includes a 40-70% decrease in cytochrome P450 2C11 (CYP2C11) expression in males and a 20-30% reduction of corticosterone sulfotransferase activity in females. Changes in DME activities that occur late in life in calorically restricted rats include a stimulation of CYP2E1-dependent 4-nitrophenol hydroxylase activity and a delay in the disappearance of male-specific enzyme activities in senescent males. It is probable that altered DME expression is associated with altered metabolic activation of chemical carcinogens. For example the relative expression of hepatic CYP2C11 in ad libitum-fed or calorically restricted rats of different ages is closely correlated with the amount of genetic damage in 2-acetylaminofluorene- or aflatoxin B1-pretreated hepatocytes isolated from rats of the same age and caloric intake. This suggests that altered hepatic drug and carcinogen metabolism in calorically restricted rats can influence the carcinogenicity of test chemicals.
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Affiliation(s)
- M Manjgaladze
- Division of Biometry and Risk Assessment, National Center for Toxicological Research, Jefferson, AR 72079
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Penman ID, el-Omar E, McGregor JR, Hillan KJ, O'Dwyer PJ, McColl KE. Omeprazole inhibits colorectal carcinogenesis induced by azoxymethane in rats. Gut 1993; 34:1559-65. [PMID: 8244144 PMCID: PMC1374422 DOI: 10.1136/gut.34.11.1559] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Numerous clinical and experimental studies suggest that gastrin plays an important part in the development of colorectal cancer in humans. This study was done to assess the influence of omeprazole induced hypergastrinaemia on the development of colorectal tumours in an experimental animal model. Forty female Sprague-Dawley rats received either omeprazole (40 mumol/kg) or vehicle (0.25% methylcellulose) by once daily oral gavage throughout the experiment. All animals received 12 consecutive weekly subcutaneous injections of azoxymethane (10 mg/kg/week) beginning at week 6. Serum gastrin concentrations were measured during weeks 1 and 5 and at death (week 27). Chronic omeprazole treatment resulted in appreciable hypergastrinaemia during the study, mean gastrin concentrations in omeprazole treated rats being raised by up to nine to 10 fold, compared with vehicle treated control rats (p < 0.001). Despite this, tumour incidence in the omeprazole group was significantly lower at 63%, compared with 95% in the vehicle only group (p < 0.02). The median number of tumours in the omeprazole group (1) compared with the vehicle group (3) was also significantly lower (p = 0.02). Average tumour size, site distribution, and the comparative frequencies of adenomas and adenocarcinomas were similar in the two groups. This study shows that omeprazole protects against colorectal carcinogenesis in this model despite causing appreciable hypergastrinaemia. The mechanism by which this occurs is unclear and merits further investigation. Because of the compounding protective effects of omeprazole, this model is not a suitable one for studying the longterm trophic effects of gastrin on the colon.
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Affiliation(s)
- I D Penman
- University Department of Medicine and Therapeutics, Western Infirmary, Glasgow
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Yang EK, Radominska A, Winder BS, Dannenberg AJ. Dietary lipids coinduce xenobiotic metabolizing enzymes in rat liver. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1168:52-8. [PMID: 8504142 DOI: 10.1016/0005-2760(93)90265-b] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the role of dietary lipids in regulating the activities and amounts of epoxide hydrolase, UDP-glucuronosyltransferase and glutathione S-transferase in rat liver. Male Wistar rats were fed a fat-free (FF) diet or isocaloric control diet containing 5% corn oil (CO) or 5% fish oil (FO) for 3 weeks. The activities of these enzymes were approx. 2-fold higher in rats fed the FO diet vs. the FF diet. Intermediate levels of enzyme activity were found in rats fed the CO diet. Diet-induced differences in enzyme levels were shown by immunoblotting. The highest levels of epoxide hydrolase, UDP-glucuronosyltransferase and glutathione S-transferase were detected in rats fed the FO diet. The lowest levels of these enzymes were found in rats fed the FF diet. Intermediate levels of enzyme were found in rats fed the CO diet. Thus, diet-induced differences in enzyme activities were paralleled by changes in enzyme levels. Fatty acid analysis of microsomal lipids showed that the FF diet was associated with decreased levels of n-6 fatty acids vs. the CO diet. The FO diet resulted in increased levels of n-3 fatty acids vs. the other diets.
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Affiliation(s)
- E K Yang
- Department of Internal Medicine, Cornell University Medical College, New York, NY 10021
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