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Su PW, Yang EC, Moi SH, Yang CH, Chuang LY. Prevalence of Carbapenem Resistance Genes among Acinetobacter baumannii Isolated from a Teaching Hospital in Taiwan. Antibiotics (Basel) 2023; 12:1357. [PMID: 37760654 PMCID: PMC10525170 DOI: 10.3390/antibiotics12091357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/27/2023] [Accepted: 08/20/2023] [Indexed: 09/29/2023] Open
Abstract
The problem of antibiotic-resistant strains has become a global public issue; antibiotic resistance not only limits the choice of treatments but also increases morbidity, mortality and treatment costs. The multi-drug resistant Acinetobacter baumannii is occurring simultaneously in hospitals and has become a major public health issue worldwide. Although many medical units have begun to control the use of antibiotics and paid attention to the issue of drug resistance, understanding the transmission pathways of clinical drug-resistant bacteria and drug-resistant mechanisms can be effective in real-time control and prevent the outbreak of antibiotic-resistant pathogens. In this study, a total of 154 isolates of Acinetobacter baumannii obtained from Chia-Yi Christian Hospital in Taiwan were collected for specific resistance genotyping analysis. Ten genes related to drug resistance, including blaOXA-51-like, blaOXA-23-like, blaOXA-58-like, blaOXA-24-like, blaOXA-143-like, tnpA, ISAba1, blaPER-1, blaNDM and blaADC, and the repetitive element (ERIC2) were selected for genotyping analysis. The results revealed that 135 A. baumannii isolates (87.6%) carried the blaOXA-51-like gene, 4.5% of the isolates harbored the blaOXA-23-like gene, and 3.2% of the isolates carried the blaOXA-58-like gene. However, neither the blaOXA-24-like nor blaOXA-143-like genes were detected in the isolates. Analysis of ESBL-producing strains revealed that blaNDM was not found in the test strains, but 38.3% of the test isolates carried blaPER-1. In addition, blaADC, tnpA and ISAba1genes were found in 64.9%, 74% and 93% of the isolates, respectively. Among the carbapenem-resistant strains of A. baumannii, 68% of the isolates presenting a higher antibiotic resistance carried both tnpA and ISAba1 genes. Analysis of the relationship between their phenotypes (antibiotic resistant and biofilm formation) and genotypes (antibiotic-resistant genes and biofilm-related genes) studied indicated that the bap, ompA, ISAba1and blaOXA-51 genes influenced biofilm formation and antibiotic resistance patterns based on the statistical results of a hierarchical clustering dendrogram. The analysis of the antibiotic-resistant mechanism provides valuable information for the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens, and is an important reference pointer to prevent strains from producing resistance.
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Affiliation(s)
- Pai-Wei Su
- General Education Center, Wenzao Ursuline University of Languages, Kaohsiung 80793, Taiwan;
| | - Emirlyn Cheng Yang
- Department of Post-Baccalaureate Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Sin-Hua Moi
- Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Cheng-Hong Yang
- Department of Information Management, Tainan University of Technology, Tainan 71002, Taiwan
- Ph. D. Program in Biomedical Engineering, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Li-Yeh Chuang
- Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 84001, Taiwan
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O'Hanlan KA, Gordon JC, Sullivan MW. Biological origins of sexual orientation and gender identity: Impact on health. Gynecol Oncol 2018; 149:33-42. [PMID: 29605047 DOI: 10.1016/j.ygyno.2017.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 10/30/2017] [Accepted: 11/07/2017] [Indexed: 01/19/2023]
Abstract
Gynecologic Oncologists are sometimes consulted to care for patients who present with diverse gender identities or sexual orientations. Clinicians can create more helpful relationships with their patients if they understand the etiologies of these diverse expressions of sexual humanity. Multidisciplinary evidence reveals that a sexually dimorphic spectrum of somatic and neurologic anatomy, traits and abilities, including sexual orientation and gender identity, are conferred together during the first half of pregnancy due to genetics, epigenetics and the diversity of timing and function of sex chromosomes, sex-determining protein secretion, gonadal hormone secretion, receptor levels, adrenal function, maternally ingested dietary hormones, fetal health, and many other factors. Multiple layers of evidence confirm that sexual orientation and gender identity are as biological, innate and immutable as the other traits conferred during that critical time in gestation. Negative social responses to diverse orientations or gender identities have caused marginalization of these individuals with resultant alienation from medical care, reduced self-care and reduced access to medical care. The increased risks for many diseases, including gynecologic cancers are reviewed. Gynecologic Oncologists can potentially create more effective healthcare relationships with their patients if they have this information.
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Affiliation(s)
- Katherine A O'Hanlan
- Laparoscopic Institute for Gynecology and Oncology (LIGO), 4370 Alpine Rd. Suite 104, Portola Valley, CA 94028, United States.
| | - Jennifer C Gordon
- University of Tennessee Health Sciences Center, Memphis, TN, United States.
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Abstract
Undescended testis - known as cryptorchidism - is one of the most common congenital abnormalities observed in boys, and is one of the few known risk factors for testicular cancer. The key factors that contribute to the occurrence of cryptorchidism remain elusive. Testicular descent is thought to occur during two hormonally-controlled phases in fetal development - between 8-15 weeks (the first phase of decent) and 25-35 weeks gestation (the second phase of descent); the failure of a testis to descend permanently is probably caused by disruptions to one or both of these phases, but the causes and mechanisms of such disruptions are still unclear. A broad range of putative risk factors have been evaluated in relation to the development of cryptorchidism but their plausibility is still in question. Consistent evidence of an association with cryptorchidism exists for only a few factors, and in those cases in which evidence seems unequivocal the factor is likely to be a surrogate for the true causal exposure. The relative importance of each risk factor could vary considerably between mother-son pairs depending on an array of genetic, maternal, placental and fetal factors - all of which could vary between regions. Thus, the role of causative factors in aetiology of cryptorchidism requires further research.
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Bath KG, Scharfman HE. Impact of early life exposure to antiepileptic drugs on neurobehavioral outcomes based on laboratory animal and clinical research. Epilepsy Behav 2013; 26:427-39. [PMID: 23305780 PMCID: PMC3925312 DOI: 10.1016/j.yebeh.2012.10.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 10/30/2012] [Indexed: 12/13/2022]
Abstract
Epilepsy affects approximately 1% of children under the age of 15, making it a very common neurological disorder in the pediatric population (Russ et al., 2012). In addition, ~0.4-0.8% of all pregnant women have some form of epilepsy (Hauser et al., 1996a,b; Borthen et al., 2009; Krishnamurthy, 2012). Despite the potential deleterious effects of antiepileptic drugs (AEDs) on the developing brain, their use is still required for seizure control in pregnant women (Krishnamurthy, 2012), and they represent the standard approach for treating children with epilepsy (Chu-Shore and Thiele, 2010; Quach et al., 2010; Verrotti et al., 2011). Even when AEDs are effective, there are potential side effects, including cognitive and affective changes or altered sleep and appetite. The consequences of AED exposure in development have been studied extensively (Canger et al., 1999; Modi et al., 2011a,b; Oguni, 2011). Despite intensive study, there is still debate about the long-term consequences of early life AED exposure. Here, we consider the evidence to date that AED exposure, either prenatally or in early postnatal life, has significant adverse effects on the developing brain and incorporate studies of laboratory animals as well as those of patients. We also note the areas of research where greater clarity seems critical in order to make significant advances. A greater understanding of the impact of AEDs on somatic, cognitive and behavioral development has substantial value because it has the potential to inform clinical practice and guide studies aimed at understanding the genetic and molecular bases of comorbid pathologies associated with common treatment regimens. Understanding these effects has the potential to lead to AEDs with fewer side effects. Such advances would expand treatment options, diminish the risk associated with AED exposure in susceptible populations, and improve the quality of life and health outcomes of children with epilepsy and children born to women who took AEDs during pregnancy.
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Affiliation(s)
- Kevin G. Bath
- Department of Neuroscience, Brown University, Box GL-N, 185 Meeting St., Providence, RI 02912, USA,Corresponding author. (K.G. Bath)
| | - Helen E. Scharfman
- The Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Rd., Bldg. 35, Orangeburg, NY 10962, USA,New York University Langone Medical Center, 550 First Ave., New York, NY 10016, USA
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Antiepileptic treatment in pregnant women: morphological and behavioural effects. Handb Exp Pharmacol 2011; 205:295-315. [PMID: 21882118 DOI: 10.1007/978-3-642-20195-0_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It is well established that children exposed to antiepileptic drugs (AEDs) in utero have an increased risk of adverse pregnancy outcomes including foetal growth retardation, major congenital malformations and impaired postnatal cognitive development. However, due to the significant maternal and foetal risks associated with uncontrolled epileptic seizures, AED treatment is generally maintained during pregnancy in the majority of women with active epilepsy. The prevalence of major malformations in children exposed to AEDs has ranged from 4 to 10%, 2-4 times higher than in the general population. More recent studies suggest a smaller increase in malformation rates. Malformation rates have consistently been higher in association with exposure to valproate than with carbamazepine and lamotrigine. Some prospective cohort studies also indicate reduced cognitive outcome in children exposed to valproate compared to carbamazepine and possibly lamotrigine. Information on pregnancy outcomes with newer generation AEDs other than lamotrigine are still insufficient.
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Ren H, Aleksunes LM, Wood C, Vallanat B, George MH, Klaassen CD, Corton JC. Characterization of peroxisome proliferator-activated receptor alpha--independent effects of PPARalpha activators in the rodent liver: di-(2-ethylhexyl) phthalate also activates the constitutive-activated receptor. Toxicol Sci 2009; 113:45-59. [PMID: 19850644 DOI: 10.1093/toxsci/kfp251] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator chemicals (PPC) are thought to mediate their effects in rodents on hepatocyte growth and liver cancer through the nuclear receptor peroxisome proliferator-activated receptor (PPAR) alpha. Recent studies indicate that the plasticizer di-(2-ethylhexyl) phthalate (DEHP) increased the incidence of liver tumors in PPARalpha-null mice. We hypothesized that some PPC, including DEHP, induce transcriptional changes independent of PPARalpha but dependent on other nuclear receptors, including the constitutive-activated receptor (CAR) that mediates phenobarbital (PB) effects on hepatocyte growth and liver tumor induction. To determine the potential role of CAR in mediating effects of PPC, a meta-analysis was performed on transcript profiles from published studies in which rats and mice were exposed to PPC and compared the profiles to those produced by exposure to PB. Valproic acid, clofibrate, and DEHP in rat liver and DEHP in mouse liver induced genes, including Cyp2b family members that are known to be regulated by CAR. Examination of transcript changes by Affymetrix ST 1.0 arrays and reverse transcription-PCR in the livers of DEHP-treated wild-type, PPARalpha-null, and CAR-null mice demonstrated that (1) most (approximately 94%) of the transcriptional changes induced by DEHP were PPARalpha-dependent, (2) many PPARalpha-independent genes overlapped with those regulated by PB, (3) induction of genes Cyp2b10, Cyp3a11, and metallothionine-1 by DEHP was CAR dependent but PPARalpha-independent, and (4) induction of a number of genes (Cyp8b1, Gstm4, and Gstm7) was independent of both CAR and PPARalpha. Our results indicate that exposure to PPARalpha activators including DEHP leads to activation of multiple nuclear receptors in the rodent liver.
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Affiliation(s)
- Hongzu Ren
- National Health and Environmental Effects Research Lab Toxicogenomics Core, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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Hernandez J, Mota L, Baldwin W. Activation of CAR and PXR by Dietary, Environmental and Occupational Chemicals Alters Drug Metabolism, Intermediary Metabolism, and Cell Proliferation. CURRENT PHARMACOGENOMICS AND PERSONALIZED MEDICINE 2009; 7:81-105. [PMID: 20871735 PMCID: PMC2944248 DOI: 10.2174/187569209788654005] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The constitutive androstane receptor (CAR) and the pregnane × receptor (PXR) are activated by a variety of endogenous and exogenous ligands, such as steroid hormones, bile acids, pharmaceuticals, and environmental, dietary, and occupational chemicals. In turn, they induce phase I-III detoxification enzymes and transporters that help eliminate these chemicals. Because many of the chemicals that activate CAR and PXR are environmentally-relevant (dietary and anthropogenic), studies need to address whether these chemicals or mixtures of these chemicals may increase the susceptibility to adverse drug interactions. In addition, CAR and PXR are involved in hepatic proliferation, intermediary metabolism, and protection from cholestasis. Therefore, activation of CAR and PXR may have a wide variety of implications for personalized medicine through physiological effects on metabolism and cell proliferation; some beneficial and others adverse. Identifying the chemicals that activate these promiscuous nuclear receptors and understanding how these chemicals may act in concert will help us predict adverse drug reactions (ADRs), predict cholestasis and steatosis, and regulate intermediary metabolism. This review summarizes the available data on CAR and PXR, including the environmental chemicals that activate these receptors, the genes they control, and the physiological processes that are perturbed or depend on CAR and PXR action. This knowledge contributes to a foundation that will be necessary to discern interindividual differences in the downstream biological pathways regulated by these key nuclear receptors.
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Affiliation(s)
- J.P. Hernandez
- Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - L.C. Mota
- Institute of Environmental Toxicology, Clemson University, Pendleton, SC, USA
| | - W.S. Baldwin
- Institute of Environmental Toxicology, Clemson University, Pendleton, SC, USA
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TOMSON TORBJÖRN, BATTINO DINA. The Management of Epilepsy in Pregnancy. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/b978-1-4160-6171-7.00016-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
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Lemaire G, Mnif W, Pascussi JM, Pillon A, Rabenoelina F, Fenet H, Gomez E, Casellas C, Nicolas JC, Cavaillès V, Duchesne MJ, Balaguer P. Identification of New Human Pregnane X Receptor Ligands among Pesticides Using a Stable Reporter Cell System. Toxicol Sci 2006; 91:501-9. [PMID: 16565514 DOI: 10.1093/toxsci/kfj173] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pregnane X receptor (PXR, NR1I2) is activated by various chemically unrelated compounds, including environmental pollutants and drugs. We proceeded here to in vitro screening of 28 pesticides with a new reporter system that detects human pregnane X receptor (hPXR) activators. The cell line was obtained by a two-step stable transfection of cervical cancer HeLa cells. The first transfected cell line, HG5LN, contained an integrated luciferase reporter gene under the control of a GAL4 yeast transcription factor-binding site. The second cell line HGPXR was derived from HG5LN and stably expressed hPXR ligand-binding domain fused to GAL4 DNA-binding domain (DBD). The HG5LN cells were used as a control to detect nonspecific activities. Pesticides from various chemical classes were demonstrated, for the first time, to be hPXR activators: (1) herbicides: pretilachlor, metolachlor, and alachlor chloracetanilides, oxadiazon oxiconazole, and isoproturon urea; (2) fungicides: bupirimate and fenarimol pyrimidines, propiconazole, fenbuconazole, prochloraz conazoles, and imazalil triazole; and (3) insecticides: toxaphene organochlorine, permethrin pyrethroid, fipronil pyrazole, and diflubenzuron urea. Pretilachlor, metolachlor, bupirimate, and oxadiazon had an affinity for hPXR equal to or greater than the positive control rifampicin. Some of the newly identified hPXR activators were also checked for their ability to induce cytochrome P450 3A4 expression in a primary culture of human hepatocytes. HGPXR, with HG5LN as a reference, was grafted onto nude mice to assess compound bioavailability through in vivo quantification of hPXR activation. Altogether, our data indicate that HGPXR cells are an efficient tool for identifying hPXR ligands and establishing pesticides as hPXR activators.
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Kretschmer XC, Baldwin WS. CAR and PXR: xenosensors of endocrine disrupters? Chem Biol Interact 2005; 155:111-28. [PMID: 16054614 DOI: 10.1016/j.cbi.2005.06.003] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 06/14/2005] [Accepted: 06/20/2005] [Indexed: 01/05/2023]
Abstract
The pregnane X-receptor (PXR) and the constitutive androstane receptor (CAR) are orphan nuclear receptors activated by a variety of ligands. Currently it remains uncertain whether these receptors have a high-affinity ligand or instead function as more generalized steroid/xenobiotic sensors. Both receptors are important regulators of several steroid and xenobiotic detoxification enzymes and transporters (phases I-III) in the liver and intestine and thus are important regulators of adaptation to chemical stress. The detoxification proteins induced are responsible for the metabolism, deactivation and transport of bile acids, thyroid and steroid hormones, numerous environmental chemicals, and several drugs. PXR and CAR received their names because of steroid ligands that activate and inhibit their transcriptional activity, respectively. Interestingly, some steroids and steroid mimics activate one or both receptors, including several endocrine disrupting chemicals. Environmental estrogens, such as the pesticides methoxychlor, endosulfan, dieldrin, DDT, and the plasticizer nonylphenol activate either PXR or both PXR and CAR. Because PXR and CAR are activated by numerous steroids and endocrine disrupters, it appears that these receptors protect the integrity of the endocrine system. They recognize an increase in steroid-like chemicals and, in turn, induce detoxification. Furthermore, PXR and CAR induce enzymes, such as the CYP2B and CYP3A family members, responsible for the metabolism of steroid and thyroid hormones and this may alter their normal physiological function. This review summarizes the available data on the activity of endocrine disrupters and endocrine active chemicals on PXR and CAR, examines the role of PXR and CAR in protection from these chemicals, and evaluates potential adverse physiological consequences of PXR and CAR activation.
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Affiliation(s)
- Xiomara C Kretschmer
- University of Texas at El Paso, Biological Sciences, 500 W. University Ave., El Paso, TX 79968, USA
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Abstract
Migraine is common during pregnancy, but fortunately this combination of conditions obviously exists for only a finite period. The greatest frequency of migraine attacks occurs during the first trimester. Accurate diagnosis is a sine qua non in this setting as in any headache patient. It is in the first trimester that the fetus is at greatest risk from abortifacient and teratogenic drugs, and when very early pregnancy may be undiagnosed. Ergot alkaloids (including methysergide) should be avoided during pregnancy because of their teratogenicity, and most other drug classes should be used only when unavoidable. The use of prophylactic agents during pregnancy should be the exception, not the rule, and preferably only during the second and third trimesters; propranolol is probably safest in this situation. De novo headache during pregnancy usually requires expert review of the patient. Treatment tactics for uncomplicated migraine in pregnancy depend on the concurrent clinical situation. Paracetamol (acetaminophen) is the mainstay for the patient whose typical attacks continue into the first trimester. If paracetamol is insufficient, then partial agonist opioids may be used if typical migraine attacks persist in the second and third trimesters (which is uncommon). 'Chronic migraine' in pregnancy, i.e. >or=15 headache days per month, is rare, and is the greatest therapeutic challenge. Co-morbidities such as depression or epilepsy require specialised approaches. The complexities associated with these tactics are discussed in this article, and it is emphasised that none has the specific approval of regulatory authorities. Heightened pharmacovigilance will better inform the future pregnant migraineur. However, this type of information is less likely to be available for novel classes of neuropharmacological agents than for existing ones.
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Lemaire G, de Sousa G, Rahmani R. A PXR reporter gene assay in a stable cell culture system: CYP3A4 and CYP2B6 induction by pesticides. Biochem Pharmacol 2005; 68:2347-58. [PMID: 15548381 DOI: 10.1016/j.bcp.2004.07.041] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 07/16/2004] [Indexed: 12/22/2022]
Abstract
A stable hepatoma cell line expressing the human pregnane X receptor (hPXR) and the cytochrome P4503A4 (CYP3A4) distal and proximal promoters plus the luciferase reporter gene was developed to assess the ability of several xenobiotic agents to induce CYP3A4 and CYP2B6. After selection for neomycin resistance, one clone, displaying high luciferase activity in response to rifampicin (RIF), was isolated and the stable expression of hPXR was confirmed by reverse transcription polymerase chain reaction (RT-PCR). Dose-response curves were generated by treating these cells with increasing concentrations of RIF, phenobarbital (PB), clotrimazole (CLOT) or 5beta-pregnane-3,20-dione (5beta-PREGN). The effective concentrations for half maximal response (EC50) were determined for each of these compounds. RIF was the most effective compound, with maximal luciferase activity induced at 10 microM. The agonist activities of PXR-specific inducers measured using our stable model were consistent with those measured in transient transfectants. The abilities of organochlorine (OC), organophosphate (OP) and pyrethroid pesticides (PY) to activate hPXR were also assessed and found to be consistent with the abilities of these compounds to induce CYP3A4 and CYP2B6 in primary culture of human hepatocytes. These results suggest that CYP3A4 and CYP2B6 regulation through PXR activation by persistent pesticides may have an impact on the metabolism of xenobiotic agents and endogenous steroid hormones. Our model provides a useful tool for studying hPXR activation and for identifying agents capable of inducing CYP3A4 and CYP2B6.
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Affiliation(s)
- Géraldine Lemaire
- Laboratoire de Toxicologie Cellulaire, Moléculaire et Génomique INRA, UMR 1112 ROSE, 400 route des chappes, B.P. 167, 06903 Sophia Antipolis, France.
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Agrawal AK, Shapiro BH. Neonatal phenobarbital imprints overexpression of cytochromes P450 with associated increase in tumorigenesis and reduced life span. FASEB J 2005; 19:470-2. [PMID: 15634872 DOI: 10.1096/fj.04-2550fje] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Perinatal exposure to phenobarbital produces a range of permanent reproductive, growth, locomoter, and learning dysfunctions in animals as well as humans. In addition, the affected individuals exhibit latently expressed (i.e., postpubertal) above normal activity levels of hepatic multicytochrome P450-dependent drug metabolizing enzymes. We report that in spite of apparent normal health for the better part of their lives, daily administration of therapeutic-like doses of phenobarbital to male and female rat pups during the first postpartum week reduced life expectancy by approximately 20%. Necropsy at the time of natural death revealed an associated two- to threefold increase in the incidence of tumors in barbiturate-exposed rats of both sexes and a three- to fourfold increase in urinary tract pathologies in male rats. At 2 yr of age, in agreement with an overexpression of hepatic CYP2C6 and CYP2C7, both in vitro and in vivo drug metabolism was more rapid in the phenobarbital-imprinted male and female animals. Moreover, when the senescent rats were rechallenged with a nominal dose of the barbiturate, males and females neonatally exposed to phenobarbital exhibited a dramatic overinduction of multicytochrome P450-dependent drug metabolizing enzymes as well as an overexpression of individual isoforms of cytochrome P450 implicated in enhanced susceptibility to tumorigenesis. Our findings support the growing realization that many adult diseases have their origins in early life by emphasizing that unlike adults, the new born is "plastic," and even therapeutic drugs may produce "silent" programming defects that subtly, but irrevocably, jeopardize life-long well-being.
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Affiliation(s)
- Arun K Agrawal
- Laboratories of Biochemistry, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104-6048, USA
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Handschin C, Meyer UA. Regulatory network of lipid-sensing nuclear receptors: roles for CAR, PXR, LXR, and FXR. Arch Biochem Biophys 2005; 433:387-96. [DOI: 10.1016/j.abb.2004.08.030] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 08/23/2004] [Indexed: 11/28/2022]
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Biswas SJ, Pathak S, Khuda-Bukhsh AR. Assessment of the genotoxic and cytotoxic potential of an anti-epileptic drug, phenobarbital, in mice: a time course study. Mutat Res 2004; 563:1-11. [PMID: 15324744 DOI: 10.1016/j.mrgentox.2004.05.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Revised: 04/27/2004] [Accepted: 05/24/2004] [Indexed: 11/30/2022]
Abstract
To examine if chronic oral administration of phenobarbital (PB), a widely used anti-epileptic drug, has any genotoxic and cytotoxic potential in mice, a mammalian model, cytogenetic assays through several endpoints such as chromosome aberrations, induction of micronuclei, mitotic index of bone marrow cells, sperm-head anomaly in testis and enzymatic assays of several toxicity marker enzymes have been conducted by use of standard techniques. Mice of both treated (chronically receiving an oral dose of PB at 1.2 mg/kg bw) and control (without receiving PB) groups were sacrificed at 7, 15, 30, 60, 90 and 120 days for the study with all the above-mentioned protocols. Further, total protein profiles in liver of both control and treated mice were analyzed through the SDS-PAGE technique at day 60. The results of all these studies, when compared with controls, showed that PB has both genotoxic and cytotoxic potential in apparently increasing intensity at longer periods of chronic feeding in mice, which would warrant due consideration in its long-term use on human subjects.
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Affiliation(s)
- Surjyo Jyoti Biswas
- Cytogenetics Laboratory, Department of Zoology, University of Kalyani, West Bengal 741235, India
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You L. Steroid hormone biotransformation and xenobiotic induction of hepatic steroid metabolizing enzymes. Chem Biol Interact 2004; 147:233-46. [PMID: 15135080 DOI: 10.1016/j.cbi.2004.01.006] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2004] [Indexed: 11/30/2022]
Abstract
Normal reproductive development depends on the interplay of steroid hormones with their receptors at specific tissue sites. The concentrations of hormone ligands in the circulation and at target sites are maintained through coordinated regulation on steroid biosynthesis and degradation. Changed bioavailability of steroids, through alteration of steroidogenesis or biotransformation rates, leads to changes in endocrine function. Steroid hormones lose their receptor reactivity in most cases when they are bound to binding proteins, while metabolic conversion can result in either active or inactive metabolites. Hydroxylation by cytochrome P450 (CYP) enzymes and conjugation with glucuronide and sulfate are among the major hepatic pathways of steroid inactivation. The expression of these biotransformation enzymes can be induced by many xenobiotics. The barbiturate phenobarbital and the environmental toxicant 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) are among the well characterized inducers for the CYP 2B and 3A enzymes and selected conjugation enzymes. The induction of the steroid biotransformation enzymes is partly mediated through the activation of a group of nuclear receptors including the glucocorticoid receptor, the constitutive androstane receptor (CAR), the pregnane X receptor (PXR), and the peroxisome proliferator activated receptors (PPAR). Drug or chemical-induced increases in hepatic enzyme activities are often a basis for drug-drug interactions that lead to enhanced elimination and reduced therapeutic efficacy of steroidal drugs. The effects of enzyme induction on endogenous steroid clearance, along with its possible consequence, are less well understood. While enzyme induction by xenobiotics may increase clearance of the endogenous steroid, regulatory mechanisms for steroid homeostasis may adapt and compensate for altered clearance.
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Affiliation(s)
- Li You
- CIIT Centers for Health Research, 6 Davis Drive, P.O. Box 12137, Research Triangle Park, NC 27709-2137, USA.
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Wyde ME, Bartolucci E, Ueda A, Zhang H, Yan B, Negishi M, You L. The environmental pollutant 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene induces rat hepatic cytochrome P450 2B and 3A expression through the constitutive androstane receptor and pregnane X receptor. Mol Pharmacol 2003; 64:474-81. [PMID: 12869653 DOI: 10.1124/mol.64.2.474] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a persistent environmental contaminant, is a metabolite of the pesticide 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). DDE is similar to phenobarbital (PB) in that both compounds are inducers of rat hepatic cytochrome P450 2B and 3A (CYP 2B and 3A). The induction of CYP 2B and 3A by PB is known to be regulated through the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), respectively. In the current study, the induction of hepatic CYP 3A1 and 2B1 by DDE was correlated with CAR and PXR activity. Induction of 3A1 and 2B1 was observed in the livers of adult and developing male Sprague-Dawley rats following exposure to DDE. Increased hepatic expression of 3A1, but not 2B1, in developing rats exposed during gestation and lactation persisted into adulthood. In receptor transactivation assays, both CAR and PXR transcriptional activities were significantly enhanced by DDE. Nuclear accumulation of CAR, but not PXR, was observed in the liver tissue following DDE and PB treatment. These data support the idea that induction of hepatic 3A1 and 2B1 by DDE is mediated through the activation of CAR and PXR. This study suggests that regulation by environmental compounds of hepatic enzymes via CAR and PXR may have impact on the metabolism of endogenous and exogenous substrates.
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Affiliation(s)
- Michael E Wyde
- CIIT Centers for Health Research, Research Triangle Park, North Carolina, USA
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Agrawal AK, Shapiro BH. Phenobarbital-imprinted overinduction of adult constituent CYP isoforms. Pharmacology 2003; 68:204-15. [PMID: 12837975 DOI: 10.1159/000070460] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2002] [Accepted: 01/19/2003] [Indexed: 11/19/2022]
Abstract
Newborn male and female rats were treated with therapeutic-like levels of phenobarbital to determine whether early exposure to the barbiturate permanently alters (i.e., imprints) mechanisms regulating induction of constituent CYP (cytochrome P-450) isoforms. When the rats were 65 and 150 days old, they were rechallenged with phenobarbital at doses reflecting either the possible inducing activities of environmental agents (1 mg/kg) or at the minimal anticonvulsant therapeutic dose for the rat (10 mg/kg). The expression levels (mRNA and protein) of constituent, gender-dependent CYP2C6, CYP2C7, CYP2C11, CYP2C12, CYP2C13, and CYP3A2 and nonconstitutive CYP3A1 were monitored at various times (i.e., 0.1-136 h) during the rechallenge period. The major female-specific CYP2C12 and male-specific CYP2C13 were unresponsive to induction, whereas the major male-specific CYP2C11 responded to phenobarbital administration with a 100% increase in transcript levels that were not translated into new protein. The expression of the other isoforms was significantly elevated by both doses of phenobarbital (10 mg >1 mg), though CYP2C6, CYP3A1, and CYP3A2 levels were increased an additional 30-50% when the animals were neonatally exposed to the barbiturate, demonstrating for the first time that mechanisms regulating induction of constitutive CYPs in adults are imprintable at birth. This overinduction response appears to result, at least in part, from phenobarbital-programmed alterations in the sexually dimorphic plasma growth hormone profiles that normally regulate expression of the isoforms. The long-term health consequences of the overinduction response and possible clinical significance are discussed.
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Affiliation(s)
- Arun K Agrawal
- Laboratories of Biochemistry, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104-6048, USA
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Abstract
Pregnancy in women with epilepsy (WWE) is known to be associated with a higher risk of congenital malformations than is associated with pregnancy in non-epileptic women. Several factors have been identified to account for the increased risk, including the direct teratogenic effects of antiepileptic drug (AED) therapy, indirect effects of these drugs by interfering with folate metabolism, genetic abnormalities in drug or folate metabolism, and possibly an arrhythmogenic effect of maternal drug therapy on the embryonic heart, leading to ischaemia in developing tissues. A harmful effect of maternal seizures on the developing embryo has not been proven, although seizures and status epilepticus account for most of the excess maternal mortality in women with epilepsy. Abrupt withdrawal of drug therapy by the mother may be an important contributory factor. Less is known about the psychomotor development of children born to mothers with epilepsy because few studies have been designed to follow their progress throughout childhood. Retrospective studies suggest that impaired cognitive development may be associated with maternal drug therapy, particularly valproate. There is an urgent need to evaluate these risks and, with this in mind, several prospective registers have been set up to collect data from pregnancies in women with epilepsy.
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Current awareness in pharmacoepidemiology and drug safety. Pharmacoepidemiol Drug Saf 2002; 11:169-74. [PMID: 12004884 DOI: 10.1002/pds.658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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