Identification of maternal opioid abuse in pregnancy is often difficult to ascertain in the absence of reliable self report. For this reason, physicians and child protection workers often turn to maternal and neonatal hair analysis for the detection of in utero opioid exposures. Since neonatal opiate hair analysis continues to prove difficult due to the scarcity of the hair sample and low drug concentrations, I developed a sensitive method utilizing headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the detection of three principal opiates (morphine, codeine, and 6-monoacetylmorphine) in human hair. Moreover, I characterized an at-risk neonatal population for in utero opiate exposures as well as for other drugs of abuse and alcohol. Equipped with a sensitive and specific method for the detection of opiate exposures and understanding the addiction profiles of pregnant women may lead to better clinical and social management and may benefit an at-risk population.

Statins can act as preconditioning agents against ischemia reperfusion (IR)-injury through a mechanism involving cyclooxygenase (COX)-2 and the upregulation of prostaglandin synthesis. The following study investigated the effect of selective and non-selective COX inhibition on rosuvastatin-mediated protection against IR-induced endothelial dysfunction in the human forearm vasculature. Healthy volunteers were randomized to drugs with different COX-inhibiting properties: 81mg aspirin (OD), 325mg aspirin (OD), 400mg ibuprofen (QID), 200mg celecoxib (BID) or placebo. A single dose of 40mg rosuvastatin was also administered 24-hours prior to IR. Endothelial function before and after IR was assessed by measuring flow-mediated dilation of the radial artery. Our results show that 81mg and 325mg aspirin (more COX-1 selective), 400mg ibuprofen (similar selectivity for COX-1/2) and 200mg celecoxib (COX-2 selective) all effectively abolished statin-mediated protection against IR-induced endothelial dysfunction in the forearm (2-way ANOVA, p<0.05). These findings indicate that even partial COX-2 inhibition is sufficient to attenuate statin-induced preconditioning.

Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which cause loss function of the CFTR channel on the apical surface of epithelial cells. ΔF508-CFTR, the major mutation in patients, is misfolded, retained in the endoplasmic reticulum (ER) and degraded. Small molecule corrector compounds partially rescue the trafficking defect of ΔF508-CFTR by allowing escape from the ER and trafficking to the plasma membrane where it exhibits partial function. These compounds may bind directly to the mutant protein and rescue the biosynthetic defect by inducing improved protein conformation. We tested this hypothesis by evaluating the consequence of corrector compound on the conformation of each nucleotide-binding domain (NBD) in the context of the full-length mutant protein in limited proteolytic digest studies. We found that VRT-325 was capable in partially restoring compactness only in NBD1. In comparison, ablation of the arginine framed peptide sequence: R553XR555 (ΔF508-KXK-CFTR) modified the protease resistance of NBD1, NBD2 and the full-length protein. Singly, each intervention led to a partial correction of the processing defect. Together these interventions restored processing of ΔF508-CFTR to near wild-type levels. Importantly however, a defect in NBD1 conformation persisted, as did a defect in channel activation after the combined interventions. This defect in channel activation can be fully corrected by addition of the potentiator: VX-770. The experiments performed partly elucidated ii the molecular mechanism of action for drug therapy and suppressor mutation. It is important to understand these basic concepts in hopes to layout a blue print for future drug design.

Pathological gambling is a serious disorder with lifetime prevalence between 1.1-3.5%. Evidence suggests commonalities in the neurochemical basis of pathological gambling and psychostimulant addiction. However, parallel effects of gambling and a stimulant drug have not been assessed in the same subjects. This study employed a cross-priming strategy in which 12 male pathological gamblers and 11 male controls were exposed to a 15-minute slot machine game and d-amphetamine (0.4 mg/kg). Subjective, cognitive, electrophysiological, and physiological responses were assessed. Gamblers reported greater desire to gamble after both reinforcers, when baseline motivation was controlled. Conversely, gamblers exhibited diminished cardiovascular response to amphetamine. Gamblers also exhibited decreased pre-pulse inhibition (impaired sensorimotor gating), and deficits on this index predicted greater post-amphetamine desire to gamble and decreased heart rate response to the dose. Results are consistent with possible dopaminergic sensitization in pathological gamblers, but also suggest that central noradrenergic receptor deficits contribute importantly to these effects.

Nausea and vomiting of pregnancy (NVP) affects up to 90% of pregnancies. Diclectin (doxylamine/pyridoxine) is the only anti-emetic approved in Canada for NVP, at a maximum dose of 4 tablets/day. However, some women receive higher doses, up to 12 tablets/day. In this study we compared the neurocognitive development of children from four mother-child groups: (1) NVP and >4 tablets Diclectin, (2) NVP and ≤ 4 tablets Diclectin, (3) NVP and no treatment and (4) no NVP. Children received a full age-appropriate psychological assessment. All groups scored in the normal range for IQ and cognition tests. The Diclectin-exposed groups scored significantly higher on a small number of subtests, but none of the differences could be considered clinically significant. No dose-dependent effects were observed. Above manufacturer recommended doses of Diclectin do not appear to harm neurodevelopment and should be considered safe for the treatment of NVP.

Identification of maternal opioid abuse in pregnancy is often difficult to ascertain in the absence of reliable self report. For this reason, physicians and child protection workers often turn to maternal and neonatal hair analysis for the detection of in utero opioid exposures. Since neonatal opiate hair analysis continues to prove difficult due to the scarcity of the hair sample and low drug concentrations, I developed a sensitive method utilizing headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the detection of three principal opiates (morphine, codeine, and 6-monoacetylmorphine) in human hair. Moreover, I characterized an at-risk neonatal population for in utero opiate exposures as well as for other drugs of abuse and alcohol. Equipped with a sensitive and specific method for the detection of opiate exposures and understanding the addiction profiles of pregnant women may lead to better clinical and social management and may benefit an at-risk population.

Statins can act as preconditioning agents against ischemia reperfusion (IR)-injury through a mechanism involving cyclooxygenase (COX)-2 and the upregulation of prostaglandin synthesis. The following study investigated the effect of selective and non-selective COX inhibition on rosuvastatin-mediated protection against IR-induced endothelial dysfunction in the human forearm vasculature. Healthy volunteers were randomized to drugs with different COX-inhibiting properties: 81mg aspirin (OD), 325mg aspirin (OD), 400mg ibuprofen (QID), 200mg celecoxib (BID) or placebo. A single dose of 40mg rosuvastatin was also administered 24-hours prior to IR. Endothelial function before and after IR was assessed by measuring flow-mediated dilation of the radial artery. Our results show that 81mg and 325mg aspirin (more COX-1 selective), 400mg ibuprofen (similar selectivity for COX-1/2) and 200mg celecoxib (COX-2 selective) all effectively abolished statin-mediated protection against IR-induced endothelial dysfunction in the forearm (2-way ANOVA, p<0.05). These findings indicate that even partial COX-2 inhibition is sufficient to attenuate statin-induced preconditioning.

Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which cause loss function of the CFTR channel on the apical surface of epithelial cells. ΔF508-CFTR, the major mutation in patients, is misfolded, retained in the endoplasmic reticulum (ER) and degraded. Small molecule corrector compounds partially rescue the trafficking defect of ΔF508-CFTR by allowing escape from the ER and trafficking to the plasma membrane where it exhibits partial function. These compounds may bind directly to the mutant protein and rescue the biosynthetic defect by inducing improved protein conformation. We tested this hypothesis by evaluating the consequence of corrector compound on the conformation of each nucleotide-binding domain (NBD) in the context of the full-length mutant protein in limited proteolytic digest studies. We found that VRT-325 was capable in partially restoring compactness only in NBD1. In comparison, ablation of the arginine framed peptide sequence: R553XR555 (ΔF508-KXK-CFTR) modified the protease resistance of NBD1, NBD2 and the full-length protein. Singly, each intervention led to a partial correction of the processing defect. Together these interventions restored processing of ΔF508-CFTR to near wild-type levels. Importantly however, a defect in NBD1 conformation persisted, as did a defect in channel activation after the combined interventions. This defect in channel activation can be fully corrected by addition of the potentiator: VX-770. The experiments performed partly elucidated ii the molecular mechanism of action for drug therapy and suppressor mutation. It is important to understand these basic concepts in hopes to layout a blue print for future drug design.

Pathological gambling is a serious disorder with lifetime prevalence between 1.1-3.5%. Evidence suggests commonalities in the neurochemical basis of pathological gambling and psychostimulant addiction. However, parallel effects of gambling and a stimulant drug have not been assessed in the same subjects. This study employed a cross-priming strategy in which 12 male pathological gamblers and 11 male controls were exposed to a 15-minute slot machine game and d-amphetamine (0.4 mg/kg). Subjective, cognitive, electrophysiological, and physiological responses were assessed. Gamblers reported greater desire to gamble after both reinforcers, when baseline motivation was controlled. Conversely, gamblers exhibited diminished cardiovascular response to amphetamine. Gamblers also exhibited decreased pre-pulse inhibition (impaired sensorimotor gating), and deficits on this index predicted greater post-amphetamine desire to gamble and decreased heart rate response to the dose. Results are consistent with possible dopaminergic sensitization in pathological gamblers, but also suggest that central noradrenergic receptor deficits contribute importantly to these effects.

Nausea and vomiting of pregnancy (NVP) affects up to 90% of pregnancies. Diclectin (doxylamine/pyridoxine) is the only anti-emetic approved in Canada for NVP, at a maximum dose of 4 tablets/day. However, some women receive higher doses, up to 12 tablets/day. In this study we compared the neurocognitive development of children from four mother-child groups: (1) NVP and >4 tablets Diclectin, (2) NVP and ≤ 4 tablets Diclectin, (3) NVP and no treatment and (4) no NVP. Children received a full age-appropriate psychological assessment. All groups scored in the normal range for IQ and cognition tests. The Diclectin-exposed groups scored significantly higher on a small number of subtests, but none of the differences could be considered clinically significant. No dose-dependent effects were observed. Above manufacturer recommended doses of Diclectin do not appear to harm neurodevelopment and should be considered safe for the treatment of NVP.