Postnatal outcomes in lambs exposed antenatally and acutely postnatally to fluoxetine.

Background: Approximately 1/3 of newborns exposed antenatally to selective serotonin reuptake inhibitors (SSRIs) exhibit poor neonatal adaptation. Although several potential mechanisms have been proposed, the actual mechanism has not been elucidated.

Methods: We investigated outcomes in neonatal lambs exposed prenatally or postnatally to fluoxetine (FX).

An evaluation of the ontogeny of stereoselective fluoxetine metabolism and disposition in lambs from birth to one year of age.

1. The objective was to determine the ontogeny of stereoselective fluoxetine (FX) disposition in postnatal sheep from newborn to adulthood. 2.

A validated assay to quantitate serotonin in lamb plasma using ultrahigh-performance liquid chromatography-tandem mass spectrometry: applications with LC/MS3.

An ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS) method was developed and validated for the quantification of serotonin (5-HT) in lamb plasma using [(2)d(4)]-serotonin ([(2)d(4)]-5-HT) as an internal standard. Charcoal-stripped human plasma was used as the blank matrix during validation, and 5-HT was quantitated using selected reaction monitoring. The UHPLC/MS/MS system consisted of an Agilent 1290 Infinity ultrahigh-performance liquid chromatograph coupled with an AB SCIEX QTRAP(®) 5500 hybrid linear ion trap triple quadrupole mass spectrometer.

Enzyme-inducing anticonvulsants increase plasma clearance of dexmedetomidine: a pharmacokinetic and pharmacodynamic study.

Background: Dexmedetomidine is useful during mapping of epileptic foci as it facilitates electrocorticography unlike most other anesthetic agents. Patients with seizure disorders taking enzyme-inducing anticonvulsants appear to be resistant to its sedative effects. The objective of the study was to compare the pharmacokinetic and pharmacodynamic profile of dexmedetomidine in healthy volunteers with volunteers with seizure disorders receiving enzyme-inducing anticonvulsant medications.

Validated assay for the simultaneous determination of cortisol and budesonide in human plasma using ultra high performance liquid chromatography-tandem mass spectrometry.

An ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS) method was developed and validated for the quantification of cortisol and budesonide in human plasma. Charcoal stripped human plasma was used as the blank matrix during validation. Cortisol, budesonide, and dexamethasone (internal standard) were extracted from human plasma with methyl-tert-butyl ether, and the chromatographic separation of the peaks was achieved using a Waters Acquity UPLC BEH C18, 1.

A discovery study of daunorubicin induced cardiotoxicity in a sample of acute myeloid leukemia patients prioritizes P450 oxidoreductase polymorphisms as a potential risk factor.

Anthracyclines are very effective chemotherapeutic agents; however, their use is hampered by the treatment-induced cardiotoxicity. Genetic variants that help define patient's sensitivity to anthracyclines will greatly improve the design of optimal chemotherapeutic regimens. However, identification of such variants is hampered by the lack of analytical approaches that address the complex, multi-genic character of anthracycline induced cardiotoxicity (AIC).

A correlation between cytotoxicity and reductase-mediated metabolism in cell lines treated with doxorubicin and daunorubicin.

The role of metabolism in daunorubicin (DAUN)- and doxorubicin (DOX)-associated toxicity in cancer patients is dependent on whether the parent drugs or major metabolites, doxorubicinol (DOXol) and daunorubicinol (DAUNol), are the more toxic species. Therefore, we examined whether an association exists between cytotoxicity and the metabolism of these drugs in cell lines from nine different tissues. Cytotoxicity studies using MTT [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide] cell viability assays revealed that four cell lines [HepG2 (liver), HCT-15 (colon), NCI-H460 (lung), and A-498 (kidney)] were more tolerant to DAUN and DOX than the five remaining cell lines [H9c2 (heart), PC-3 (prostate), OVCAR-4 (ovary), PANC-1 (pancreas), and MCF-7 (breast)], based on significantly higher LC50 values at incubation times of 6, 24, and 48 hours.

Single-nucleotide polymorphisms in reductase genes are not associated with response to daunorubicin-based remission induction.

Background: To improve the quality of care for patients with acute myeloid leukemia (AML), biomarkers predictive of response to the standard daunorubicin-based induction therapy are needed. Genetic variants affecting daunorubicin metabolism are attractive candidates for such biomarkers.

Methods: We have previously shown that 13 of the naturally occurring nonsynonymous single-nucleotide polymorphisms (SNP) in the reductase genes affect daunorubicin metabolism in vitro.

Single-nucleotide polymorphisms in aldo-keto and carbonyl reductase genes are not associated with acute cardiotoxicity after daunorubicin chemotherapy.

Background: Evidence suggests that interpatient variability in anthracycline metabolic rate may contribute to the cardiotoxicity associated with anthracycline-based chemotherapy. Therefore, polymorphisms in the anthracycline metabolizing enzymes have been proposed as potential biomarkers of anthracycline-induced cardiotoxicity (AIC).

Methods: We have previously shown that 13 of the naturally occurring nonsynonymous single-nucleotide polymorphisms (nsSNP) in the aldo-keto reductases (AKR) and carbonyl reductases (CBR) reduce anthracycline metabolic rate in vitro.

Validation of a sequential extraction and liquid chromatography-tandem mass spectrometric method for determination of dihydrotestosterone, androstanediol and androstanediol-glucuronide in prostate tissues.

Androgens are key mediators of prostate development and function, a role that extends to the development of prostate diseases such as benign prostatic hyperplasia (BPH) and prostate cancer. In prostate, DHT is the major androgen and reduction and glucuronidation are the major metabolic pathways for DHT elimination. A streamlined method for quantitation of dihydrotestosterone (DHT), 5α-androstan-3α,17β-diol (3α-diol), and 3α-diol glucuronide (diol-gluc) was established and validated for use with archived prostate tissue specimens to facilitate examination of the roles of the underlying metabolism.

The effect of operational stressors on ibuprofen pharmacokinetics.

Purpose: To determine whether two of the major operational stressors associated with military missions in Afghanistan: dry heat and long durations of soldier patrol (SP), alter the pharmacokinetics of ibuprofen.

Methods: Thirteen healthy and physically fit participants (19-32 years) were randomized to a four-arm crossover study, as follows: Arm 4 consisted of a simulated 2.5 h SP on a treadmill set at 4.

Ontogenesis of phase I hepatic drug metabolic enzymes in sheep.

Cytochrome P450 (CYP) enzymes are important for the metabolism of many drugs. While there is information on their identity and ontogeny in humans and rodents, similar data in sheep are lacking. In the present study, cDNA sequences of several CYP enzymes (CYP2A6, CYP2C19, CYP2D6) were cloned by rapid amplification of cDNA ends.

Third trimester fetal pulmonary artery Doppler blood flow velocity characteristics following prenatal selective serotonin reuptake inhibitor (SSRI) exposure.

Background: There have been contradictory reports on the risks of persistent pulmonary hypertension (PPHN) in infants exposed to SSRIs in utero. However, there has been no assessment of fetal pulmonary arterial dynamics in such pregnancies. AIMS AND SUBJECTS: To measure fetal right pulmonary artery (RPA) variables using Doppler ultrasound at 36 weeks gestation in fetuses of mothers taking SSRI antidepressants (n=23) and in a control, normal pregnancy group (n=35).

Third trimester fetal heart rate and Doppler middle cerebral artery blood flow velocity characteristics during prenatal selective serotonin reuptake inhibitor exposure.

Prenatal selective serotonin reuptake inhibitor (SSRI) exposure increases the risk for adverse neonatal behavioral outcomes; although it is unknown whether altered brain function is present before birth. We investigated fetal vascular and heart rate changes at 36-wk gestation in SSRI-treated women with mood disorders (n = 29) [exposed (EXP)] and controls (n = 45) [non-EXP (NEXP)]. Fetal middle cerebral artery (MCA) flow parameters and heart rate characteristics were obtained during pre-SSRI dose morning and postdose afternoon sessions.

Ontogenesis of UDP-glucuronosyltransferase enzymes in sheep.

UDP glucuronosyltransferases (UGTs) are important for the metabolism of many drugs. To understand the ontogeny of these enzymes in sheep (Ovis aries), knowledge of their expression levels at different developmental stages is important. cDNA sequences of six UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A6 and UGT1A9) were cloned in sheep liver by rapid amplification of cDNA ends.

A validated enantioselective assay for the simultaneous quantitation of (R)-, (S)-fluoxetine and (R)-, (S)-norfluoxetine in ovine plasma using liquid chromatography with tandem mass spectrometry (LC/MS/MS).

A liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was developed and validated for the quantitation of (R)-, (S)-fluoxetine, and (R)-, (S)-norfluoxetine in ovine plasma. The analytes were extracted from ovine plasma at a basic pH using a single-step liquid-liquid extraction with methyl-tert-butyl ether. Chromatographic separation of all enantiomers was achieved using an AGP-chiral column with a run time of 10 min.

Pharmacogenetic impact of UDP-glucuronosyltransferase metabolic pathway and multidrug resistance-associated protein 2 transport pathway on mycophenolic acid in thoracic transplant recipients: an exploratory study.

Study Objective: To assess the contribution of polymorphisms in the uridine diphosphate glucuronosyltransferase gene (UGT) and the multidrug resistance-associated protein 2 gene (ABCC2) to mycophenolic acid (MPA) pharmacokinetics and clinical outcomes in thoracic transplant recipients.

Design: Open-label, cross-sectional study.

Setting: Transplant clinic in Vancouver, British Columbia, Canada.

Naturally occurring variants of human aldo-keto reductases with reduced in vitro metabolism of daunorubicin and doxorubicin.

Doxorubicin (DOX) and daunorubicin (DAUN) are effective anticancer drugs; however, considerable interpatient variability exists in their pharmacokinetics. This may be caused by altered metabolism by nonsynonymous single-nucleotide polymorphisms (ns-SNPs) in genes encoding aldo-keto reductases (AKRs) and carbonyl reductases. This study examined the effect of 27 ns-SNPs, in eight human genes, on the in vitro metabolism of both drugs to their major metabolites, doxorubicinol and daunorubicinol.

Naturally occurring variants of human CBR3 alter anthracycline in vitro metabolism.

Doxorubicin (DOX) and daunorubicin (DAUN) are anthracycline anticancer agents; however, considerable interpatient variability exists in their pharmacokinetics. This interpatient variability is attributed in part to altered metabolism by nonsynonymous single-nucleotide polymorphisms (ns-SNPs) in genes encoding the carbonyl reductases. This study examines the effect of seven naturally occurring ns-SNPs in the CBR3 gene on in vitro metabolism of anthracyclines to doxorubicinol and daunorubicinol.

The effect of allelic variation in aldo-keto reductase 1C2 on the in vitro metabolism of dihydrotestosterone.

Aldo-keto reductase (AKR) 1C2 is a human, cytosolic enzyme that has an important role in the deactivation of the potent androgen dihydrotestosterone (DHT). AKR1C2 can regulate the extent and duration of activation of the androgen receptor by catalyzing the reduction of DHT to the less potent receptor ligand 3alpha-diol. In this study, we functionally characterize in vitro the effect of 11 naturally occurring nonsynonymous single nucleotide polymorphisms on the ability of AKR1C2 to reduce DHT to 3alpha-diol.

Two nonsynonymous single nucleotide polymorphisms of human carbonyl reductase 1 demonstrate reduced in vitro metabolism of daunorubicin and doxorubicin.

Carbonyl reductases (CBRs) are a group of metabolic enzymes belonging to the short-chain dehydrogenase family with NADPH-dependent oxidoreductase activity. These enzymes are known to metabolize the anthracyclines doxorubicin (DOX) and daunorubicin (DAUN). Both DOX and DAUN are highly effective in cancer therapy; however, there is considerable interpatient variability in adverse effects seen in patients undergoing treatment with these drugs.

Hypothalamic-pituitary-adrenal (HPA) axis function in 3-month old infants with prenatal selective serotonin reuptake inhibitor (SSRI) antidepressant exposure.

Background: Prenatal exposure to stress and selective serotonin reuptake inhibitors (SSRIs) alter hypothalamic-pituitary-adrenal (HPA) stress reactivity in offspring, however, the effects of combined exposure to HPA activity in human infants is unknown.

Objective: To examine HPA basal levels and stress responsiveness in 3-month olds with prenatal exposure to SSRIs.

Methods: Salivary cortisol levels in infants of SSRI treated mothers (n=31, mean exposure 230.

Pharmacokinetics of mycophenolic acid and its phenolic-glucuronide and ACYl glucuronide metabolites in stable thoracic transplant recipients.

Mycophenolate mofetil is an immunosuppressant commonly used in solid organ transplantation. Its active metabolite, mycophenolic acid (MPA), is metabolized to the inactive 7-O-mycophenolic acid glucuronide (MPAG) and the active acyl glucuronide (AcMPAG). Most pharmacokinetic (PK) studies have been focused on MPA, but not its metabolites, in kidney transplant recipients.

Aldo-keto reductase 1C2 fails to metabolize doxorubicin and daunorubicin in vitro.

The anthracycline drugs are important for the treatment of a number of malignancies; however, their clinical use is associated with dose-dependent severe chronic cardiotoxicity. Although the mechanism for this side effect has not yet been identified, the alcohol metabolites formed during daunorubicin (DAUN) and doxorubicin (DOX) therapies have been implicated. The alcohol metabolites of DAUN and DOX, daunorubicinol (DAUNol) and doxorubicinol (DOXol), respectively, are generated through reduction of the C-13 carbonyl function, which is reportedly mediated by members of the aldo-keto reductase and carbonyl reductase families of proteins.

Major congenital malformations following prenatal exposure to serotonin reuptake inhibitors and benzodiazepines using population-based health data.

Background: To determine a population-based incidence of congenital anomalies following prenatal exposure to serotonin reuptake inhibitor (SRI) antidepressants used alone and in combination with a benzodiazepines (BZ).

Methods: Population health data, maternal health, and prenatal prescription records were linked to neonatal records, representing all live births (British Columbia, Canada, N=119,547) during a 39-month period (1998-2001). The incidence and risk differences (RD) for major congenital anomalies (CA) and congenital heart disease (CHD), including ventricular and atrial septal defects (VSD, ASD), from infants of mothers treated with an SRI alone, a benzodiazepine (BZ) alone, or SRI+BZ in combinationcompared to outcomesno exposure.