Attitudes On The Role Of Nutrition In GP Training.

Aim Nutrition is the leading cause of chronic disease globally, yet it is unknown how much nutritional education GP trainees receive. The aim is to identify GP trainee attitudes to nutrition and compare with the programme directors who deliver this training. Methods A multicentre online survey questionnaire of 542 GP trainees in Ireland and 63 programme directors over 2 weeks in September 2019. ANOVA analysis was used to determine if there was an agreement between programme directors and trainees. Results 13 GP training schemes participated, with 93 trainees (16%) and 9 (14%) programme directors answering the survey. There was consensus and agreement between trainees and programme directors for the following; it is the role of the GP to promote a healthy diet; there are barriers to optimal nutritional management; there would be interest in further education. ANOVA analysis found that there was agreement from directors and trainees in the assertion that nutritional education to date is not adequate. Discussion There is an agreement between GP trainees and their programme directors that the nutritional educational component of GP training is an unmet need. This study highlights the need for an improvement in nutritional education to maximise the management of chronic disease in Irish general practice.

Active vaccination reduces reinforcing effects of MDPV in male Sprague-Dawley rats trained to self-administer cocaine.

RATIONALE: 3,4-Methylenedioxypyrovalerone (MDPV) is a synthetic cathinone abused for its cocaine-like psychostimulant effects in "bath salts" products. While there are currently no pharmacotherapies for MDPV abuse, rodent studies suggest immunotherapy may offer a feasible treatment option. OBJECTIVES: These studies tested the capacity of active vaccination to reduce the reinforcing effects of MDPV in Sprague-Dawley rats. METHODS: Rats acquired cocaine self-administration (0.32 mg/kg/inf) on an FR1 schedule. Dose-effect functions for cocaine (0.032-1.0 mg/kg/inf) and MDPV (0.001-0.32 mg/kg/inf) were determined under an FR5 schedule. Rats in the vaccine group were immunized during cocaine self-administration. All rats transitioned to a progressive-ratio (PR) schedule to establish breakpoints for cocaine (0.1-1.0 mg/kg/inf) and MDPV (0.01-0.32 mg/kg/inf). Responding was extinguished, and cue-induced and MDPV-primed reinstatement (0.56 mg/kg, IP) were evaluated. RESULTS: No endpoints of cocaine self-administration differed between groups, but the ED50 for MDPV self-administration was significantly lower in control relative to vaccinated rats. Under the PR schedule, MDPV was ~ 2.5-fold more potent in maintaining responding in control than vaccinated rats, but Emax was not different between groups. Vaccination did not reduce MDPV-primed reinstatement, perhaps due to a decrease in antibody titer. CONCLUSIONS: Vaccination did not alter acquisition of cocaine self-administration, demonstrating pharmacological selectivity and suggesting that the vaccine did not affect learning or motivation, while effectively reducing the potency of MDPV as a reinforcer. The protective effects of the vaccine were surmounted by large unit doses of MDPV, suggesting maximal efficacy of drug-conjugate vaccines in substance abuse disorders will likely require concurrent behavior modification therapy.

The Development and Characterization of an scFv-Fc Fusion-Based Gene Therapy to Reduce the Psychostimulant Effects of Methamphetamine Abuse.

Methamphetamine (METH) continues to be among the most addictive and abused drugs in the United States. Unfortunately, there are currently no Food and Drug Administration-approved pharmacological treatments for METH-use disorder. We have previously explored the use of adeno-associated viral (AAV)-mediated gene transfer of an anti-METH monoclonal antibody. Here, we advance our approach by generating a novel anti-METH single-chain variable fragment (scFv)-Fc fusion construct (termed 7F9-Fc) packaged into AAV serotype 8 vector (called AAV-scFv-Fc) and tested in vivo and ex vivo. A range of doses [1 × 1010, 1 × 1011, and 1 × 1012 vector copies (vcs)/mouse] were administered to mice, eliciting a dose-dependent expression of 7F9-Fc in serum with peak circulating concentrations of 48, 1785, and 3831 µg/ml, respectively. Expressed 7F9-Fc exhibited high-affinity METH binding, IC50 = 17 nM. Between days 21 and 35 after vector administration, at both 1 × 1011 vc/mouse and 1 × 1012 vc/mouse doses, the AAV-7F9-Fc gene therapy significantly decreased the potency of METH in locomotor assays. On day 116 post-AAV administration, mice expressing 7F9-Fc sequestered over 2.5 times more METH in the serum than vehicle-treated mice, and METH concentrations in the brain were reduced by 1.2 times the value for vehicle mice. These data suggest that an AAV-delivered anti-METH Fc fusion antibody could be used to persistently reduce concentrations of METH in the central nervous system. SIGNIFICANCE STATEMENT: In this manuscript, we describe the testing of a novel antimethamphetamine (METH) single-chain variable fragment-Fc fusion protein delivered in mice using gene therapy. The results suggest that the gene therapy delivery system can lead to the production of significant antibody concentrations that mitigate METH's psychostimulant effects in mice over an extended time period.

Multiplexed Imaging Strategy to Distinguish Indeterminant Biliary Strictures: An Ex Vivo Study.

Introduction: Indeterminant biliary strictures can be either malignant or benign. Biliary intraepithelial neoplasia (BilIN) is the precursor lesion to cholangiocarcinoma, a deadly bile duct cancer. Current diagnostic methods are limited by inadequate amounts of cells and tissues collected. Aim: We aim to demonstrate use of fluorescently-labeled peptides specific for EGFR, claudin-1, and ErbB2 to perform multiplexed imaging of biliary neoplasia. Methods: Formalin fixed and paraffin embedded specimens resected from human biliary strictures were sectioned. A gastrointestinal pathologist used standard criteria to score immunohistochemistry from biliary neoplasia and adjacent normal epithelium from the same specimen. Peptides specific for EGFR, claudin-1, and ErbB2 were fluorescently-labeled with FITC, Cy5, and IRDye800, respectively. The fluorophores were chosen to provide spectral separation to distinguish the individual targets. Immuno fluorescence images were collected using confocal microscopy. Results: Target expression was validated using immunohistochemistry. Staining was visualized on the surface of biliary duct epithelial cells and not in the stroma. Greater fluorescence intensity was observed for peptide binding to biliary neoplasia by comparison with normal. The mean ratio for neoplasia-to-normal was 1.4, 1.7, and 1.6, respectively, and the average intensities were significantly greater for neoplasia than normal for each peptide. Peptides and antibody binding co-localized with correlation of ρ=0.64, 0.51 and 0.62, respectively. Conclusions: A panel of fluorescently-labeled peptides can distinguish BilIN and cholangiocarcinoma from normal biliary epithelium, and may be used for multiplexed imaging of indeterminant biliary strictures.

Constructing Matched Groups in Dental Observational Health Disparity Studies for Causal Effects.

INTRODUCTION: Electronic health record (EHR) systems provide investigators with rich data from which to examine actual impacts of care delivery in real-world settings. However, confounding is a major concern when comparison groups are not randomized. OBJECTIVES: This article introduced a step-by-step strategy to construct comparable matched groups in a dental study based on the EHR of the Willamette Dental Group. This strategy was employed in preparation for a longitudinal study evaluating the impact of a standardized risk-based caries prevention and management program across patients with public versus private dental insurance in Oregon. METHODS: This study constructed comparable dental patient groups through a process of 1) evaluating the need for and feasibility of matching, 2) considering different matching methods, and 3) evaluating matching quality. The matched groups were then compared for their average ratio in the number of decayed, missing, and filled tooth surfaces (DMFS + dmfs) at baseline. RESULTS: This systematic process resulted in comparably matched groups in baseline covariates but with a clear baseline disparity in caries experience between them. The weighted average ratio in our study showed that, at baseline, publicly insured patients had 1.21-times (95% CI: 1.08 to 1.32) and 1.21-times (95% CI: 1.08 to 1.37) greater number of DMFS + dmfs and number of decayed tooth surfaces (DS + ds) than privately insured patients, respectively. CONCLUSION: Matching is a useful tool to create comparable groups with EHR data to resemble randomized studies, as demonstrated by our study where even with similar demographics, neighborhood and clinic characteristics, publicly insured pediatric patients had greater numbers of DMFS + dmfs and DS + ds than privately insured pediatric patients. KNOWLEDGE TRANSFER STATEMENT: This article provides a systematic, step-by-step strategy for investigators to follow when matching groups in a study-in this case, a study based on electronic health record data. The results from this study will provide patients, clinicians, and policy makers with information to better understand the disparities in oral health between comparable publicly and privately insured pediatric patients who have similar values in individual, clinic, and community covariates. Such understanding will help clinicians and policy makers modify oral health care and relevant policies to improve oral health and reduce disparities between publicly and privately insured patients.

Effects of a methamphetamine vaccine, IXT-v100, on methamphetamine-related behaviors.

RATIONALE: Vaccines have been developed as a potential treatment for methamphetamine (meth) use disorder (MUD). Immunization with the meth vaccine IXT-v100 has previously been shown to elicit antibodies with high affinity for meth and thus may be an effective treatment for MUD. OBJECTIVES: These studies were designed to determine the efficacy of IXT-v100 on meth-taking and meth-seeking behaviors in rats. METHODS: In the acquisition and maintenance study, male and female rats were trained to self-administer meth (0.06 mg/kg/infusion) over an 8-week period following vaccination. In the last 4 weeks, the dose of meth was increased or decreased each week. To assess meth-seeking behavior, the meth-primed reactivity model was used. Rats were trained to self-administer meth for 5 weeks, followed by a 5-week or 11-week forced abstinence period during which the animals were vaccinated. Rats were then placed back into the self-administration chamber immediately after being injected with meth (1 mg/kg, i.p.) but did not receive meth during the session. Responses were recorded and used as a measure of meth seeking. RESULTS: Results from the acquisition and maintenance study in Wistar rats show that vaccination with IXT-v100 adjuvanted with glucopyranosyl lipid A stable emulsion decreases the percentage of animals that will self-administer a moderate level of meth. In the meth-primed reactivity studies, results from males showed that vaccination significantly attenuates meth-seeking behavior. CONCLUSION: Together, these results suggest vaccination with IXT-v100 may be effective at decreasing meth-taking and meth-seeking behaviors in humans suffering with MUD.

Excited state intramolecular proton transfer in hydroxyanthraquinones: Toward predicting fading of organic red colorants in art.

Compositionally similar organic red colorants in the anthraquinone family, whose photodegradation can cause irreversible color and stability changes, have long been used in works of art. Different organic reds, and their multiple chromophores, suffer degradation disparately. Understanding the details of these molecules' degradation therefore provides a window into their behavior in works of art and may assist the development of improved conservation methods. According to one proposed model of photodegradation dynamics, intramolecular proton transfer provides a kinetically favored decay pathway in some photoexcited chromophores, preventing degradation-promoting electron transfer (ET). To further test this model, we measured excited state lifetimes of substituted gas-phase anthraquinones using high-level theory to explain the experimental results. The data show a general structural trend: Anthraquinones with 1,4-OH substitution are long-lived and prone to damaging ET, while excited state intramolecular proton transfers promote efficient quenching for hydroxyanthraquinones that lack this motif.

Antibody production and pharmacokinetics of METH in rats following vaccination with the METH vaccine, IXT-v100, adjuvanted with GLA-SE.

BACKGROUND: Methamphetamine use disorder continues to be inadequately treated, but improvements are being made in the field of immunotherapeutics, including vaccines, which could provide new options for treatment. Cocaine and nicotine vaccines have been tested clinically, but have yet to elicit the necessary antibody concentrations required to be effective. Methamphetamine vaccines have been tested in multiple nonclinical models and appear promising. Improved adjuvants have the potential to further stimulate the immune system to reach effective levels of antibodies. Previously, the methamphetamine vaccine IXT-v100 was administered with GLA-SE, a toll-like receptor 4 agonist, in mice to produce higher levels of antibodies than when it was administered with two other widely used adjuvants, Alhydrogel and Sigma Adjuvant System. METHODS: The purpose of this research was to evaluate IXT-v100, given in combination with the adjuvant GLA-SE, to determine its efficacy in antagonizing methamphetamine disposition in a rat pharmacokinetic study. Additional rat studies were conducted to compare the ability of IXT-v100 manufactured with greater hapten densities to elicit higher antibody levels. RESULTS: As expected based on prior studies with anti-methamphetamine monoclonal antibodies, the antibodies resulting from vaccination with IXT-v100 altered methamphetamine pharmacokinetics by increasing serum concentrations and extending the half-life. Furthermore, intentional variations in the ratio of components during manufacturing led to production of vaccines with higher hapten densities. The higher hapten densities resulted in production of antibodies that maintained the ability to bind methamphetamine with high affinity. CONCLUSIONS: The results support continued development of IXT-v100 for the treatment of methamphetamine use disorder.

Effect of Bile Duct Ligation-induced Liver Dysfunction on Methamphetamine Pharmacokinetics and Locomotor Activity in Rats.

PURPOSE: Methamphetamine (METH) abuse is associated with hepatic dysfunction related comorbidities such as HIV, hepatitis C, and polysubstance abuse with acetaminophen-containing opioid formulations. We aimed to develop a bile duct ligation (BDL)-induced hepatic dysfunction model for studying both METH and experimental treatments for METH abuse in this comorbidity. METHODS: Sham or BDL surgery was performed in male Wistar rats on day 0. Liver function was measured throughout the study. On days 7 and 19, serum pharmacokinetics studies were performed with 1 mg/kg subcutaneous (sc) METH. On day 21, this dose was repeated to determine 2 h post-METH brain concentrations. METH-induced open field behaviors were measured every other day (days 12 - 16) with ascending sc doses (0.3 - 3 mg/kg). RESULTS: BDL transiently increased alanine aminotransferase levels and altered liver structure, which resulted in significantly greater METH serum and brain exposure. In the BDL compared to sham group, there was a longer duration of METH-induced locomotor activity (after 1 and 3 mg/kg) and stereotypy (after 3 mg/kg). CONCLUSIONS: In rats, liver dysfunction reduced METH clearance, increased brain METH concentrations, and enhanced METH effects on locomotor activity in a dose dependent manner. In addition, this model could be further developed to simulate the associated hepatic dysfunction of key METH abuse comorbidities for preclinical testing of novel pharmacotherapies for effectiveness and/or toxicity in vulnerable populations.

Changes in Spinal Height After Manual Axial Traction or Side Lying: A Clinical Measure of Intervertebral Disc Hydration Using Stadiometry

OBJECTIVES: The purpose of this study was to determine the immediate effects of a manual therapy technique consisting of axial traction compared with side lying on increased spine height after sustained loading. METHODS: Twenty-one asymptomatic participants were included. Participants either received manual therapy technique consisting of manual axial traction force for 2 consecutive rounds of 3 minutes or sustained side lying for 10 minutes. Spine height was measured using a commercially available stadiometer. Spinal height change was determined from measurements taken after loaded walking and measurements taken after manual therapy. A paired t test was performed to determine if a manual therapy technique consisting of axial traction increased spinal height after a period of spinal loading. RESULTS: A significant increase in height was found after both manual therapy technique and sustained side lying (P < .0001). The mean height gain was 8.60 mm using 3-dimensional axial separation. CONCLUSION: This study is an initial attempt at evaluating the biomechanical effects of manual therapy technique consisting of axial traction. Both manual axial traction force and sustained side-lying position were equally effective for short-term change in spine height after a loaded walking protocol among healthy asymptomatic individuals. This study protocol may help to inform future studies that evaluate spine height after loading.

In Utero Exposure to Norbuprenorphine, a Major Metabolite of Buprenorphine, Induces Fetal Opioid Dependence and Leads to Neonatal Opioid Withdrawal Syndrome.

Buprenorphine is the preferred treatment of opioid use disorder during pregnancy but can cause fetal opioid dependence and neonatal opioid withdrawal syndrome (NOWS). Notably, withdrawal severity is independent of maternal buprenorphine dose, suggesting that interindividual variance in pharmacokinetics may influence risk and severity of NOWS. Using a rat model of NOWS, we tested the hypothesis that clinically relevant doses of the active metabolite norbuprenorphine (NorBUP) can induce in utero opioid dependence, manifested as naltrexone-precipitated withdrawal signs in the neonate. Pregnant Long-Evans rats were implanted with 14-day osmotic minipumps containing vehicle, morphine (positive control), or NorBUP (0.3-10 mg/kg per day) on gestation day 9. By 12 hours post-delivery, an intraperitoneal injection of the opioid antagonist naltrexone (1 or 10 mg/kg) or saline was administered to pups. Precipitated withdrawal signs were graded by raters blinded to treatment conditions. In a separate group, NorBUP concentrations in maternal and fetal blood and brain on gestation day 20 were determined by liquid chromatography-tandem mass spectrometry. Steady-state maternal blood concentrations of NorBUP in dams infused with 1 or 3 mg/kg per day were comparable to values reported in pregnant humans treated with buprenorphine (1.0 and 9.6 ng/ml, respectively), suggesting a clinically relevant dosing regimen. At these doses, NorBUP increased withdrawal severity in the neonate as shown by an evaluation of 10 withdrawal indicators. These findings support the possibility that NorBUP contributes to fetal opioid dependence and NOWS following maternal buprenorphine treatment during pregnancy.

Digital depression screening in HIV primary care in South Africa: mood in retroviral + application monitoring [MIR + IAM].

BACKGROUND: Integrating mental health care into HIV services is critical to addressing the high unmet treatment needs for people living with HIV and comorbid major depressive disorder. Introducing routine mental health screening at the primary health care level is a much needed diagonal approach to enhancing HIV care. In low-resource settings with a shortage of mental health care providers, eMental Health may provide a novel opportunity to attenuate this treatment gap and strengthen the health system. OBJECTIVE: To conduct formative health systems research on the implementation of routine depression screening using a digital tool - Mood in Retroviral Positive Individuals Application Monitoring (MIR  +  IAM) - in an HIV primary care setting in South Africa. METHODS: A Theory of Change (ToC) approach was utilised through individual and group session interviews to design an intervention that is embedded in the local context. Ten experts and local stakeholders were selected from the UK and South Africa. Data were analysed thematically using Atlas.ti to identify interventions, assumptions, barriers and facilitators of implementation. FINDINGS: The participants considered digital depression screening in HIV care services relevant for the improvement of mental health in this population. The six main themes identified from the ToC process were: (1) user experience including acceptability by patients, issues of patient privacy and digital literacy, and the need for a patient-centred tool; (2) benefits of the digital tool for data collection and health promotion; (3) availability of treatment after diagnosis; (4) human and physical resource capacity of primary health care; (5) training for lay health care workers; and (6) demonstration of the intervention's usefulness to generate interest from decision-makers. CONCLUSION: Digital depression screening coupled with routine mental health data collection and analysis in HIV care is an applicable service that could improve the mental and physical health outcomes of this population. Careful consideration of the local health system capacity, including both workers and patients, is required. Future research to refine this intervention should focus on service users, government stakeholders and funders.

Cardiovascular effects of 3,4-methylenedioxypyrovalerone (MDPV) in male and female Sprague-Dawley rats.

BACKGROUND: 3,4-methylenedioxypyrovalerone (MDPV) toxicity includes intense neurological and cardiovascular events. We examined MDPV-induced cardiovascular, temperature, and locomotor effects following escalating and repeated MDPV administration in adult male and female Sprague-Dawley rats and compared these effects to cocaine in male rats. METHODS: Telemetry devices were surgically implanted to allow continuous measurement of cardiovascular, temperature, and locomotor activity over a 22 h period after dosing. Rats were administered increasing intraperitoneal (IP) MDPV doses (1-5.6 mg/kg) every other day, followed two days later by a binge regimen of four injections of 3 mg/kg MDPV at 2 h intervals. MDPV serum concentrations were measured by LC-MS/MS. Cocaine (3-30 mg/kg) and four injections of 30 mg/kg IP were administered to male rats for comparison with male MDPV data. RESULTS: The duration of MDPV cardiovascular effects was significantly greater (p < 0.05) in male rats than female rats at 3-5.6 mg/kg. The ED50 for MDPV-induced locomotor was significantly lower in males (2.4 ± 0.3) than females (3.4 ± 0.2). Males showed significantly greater variability in MDPV serum concentrations than females after binge dosing. MDPV produced five-fold more potent cardiovascular effects than cocaine in male rats. MDPV did not alter thermoregulation in either sex, but cocaine binge administration decreased temperature. CONCLUSION: Effects of MDPV on temperature were not significantly different between sexes. MDPV-induced cardiovascular and locomotor effects in males lasted significantly longer and were more potent than in females. These differences appeared to be related to pharmacokinetic factors leading to greater variance in MDPV serum concentrations in males.

Development and testing of AAV-delivered single-chain variable fragments for the treatment of methamphetamine abuse.

Methamphetamine (METH) substance abuse disorders have major impact on society, yet no medications have proven successful at preventing METH relapse or cravings. Anti-METH monoclonal antibodies can reduce METH brain concentrations; however, this therapy has limitations, including the need for repeated dosing throughout the course of addiction recovery. An adeno-associated viral (AAV)-delivered DNA sequence for a single-chain variable fragment could offer long-term, continuous expression of anti-METH antibody fragments. For these studies, we injected mice via tail vein with 1 x 10(12) vector genomes of two AAV8 scFv constructs and measured long-term expression of the antibody fragments. Mice expressed each scFv for at least 212 days, achieving micromolar scFv concentrations in serum. In separate experiments 21 days and 50 days after injecting mice with AAV-scFvs mice were challenged with METH in vivo. The circulating scFvs were capable of decreasing brain METH concentrations by up to 60% and sequestering METH in serum for 2 to 3 hrs. These results suggest that AAV-delivered scFv could be a promising therapy to treat methamphetamine abuse.

Effectiveness of a Retention Program to Improve Performance During the First Semester of a Doctor of Physical Therapy Program.

BACKGROUND: To meet the expanding need for physical therapists universities are under increasing pressure to enroll, educate, and train physical therapists. Poor academic performance can result in student dismissal from a physical therapy program. The purpose of this study is to determine if implementation of a retention program would improve student academic performance in the foundational science curriculum in a physical therapy program. METHODS: A prospective observational cohort design was used. The retention program centered on three approaches: 1. Early identification of at-risk students. 2. Supplemental instruction in Human Anatomy. 3. Offering peer tutoring for the foundational science courses. RESULTS: A significant association existed between the implementation of the retention program and the reduction of dismissals from the Fall Semester of 2012 to the fall 2013 semesters. CONCLUSION: Implementation of a retention program had a beneficial effect on decreasing student dismissals in a physical therapy program.

Considering the role of adolescent sex steroids in schizophrenia.

Schizophrenia is a disabling illness that is typically first diagnosed during late adolescence to early adulthood. It has an unremitting course and is often treatment-resistant. Many clinical aspects of the illness suggest that sex steroid-nervous system interactions may contribute to the onset, course of symptoms and the cognitive impairment displayed by men and women with schizophrenia. Here, we discuss the actions of oestrogen and testosterone on the brain during adolescent development and in schizophrenia from the perspective of experimental studies in animals, human post-mortem studies, magnetic resonance imaging studies in living humans and clinical trials of sex steroid-based treatments. We present evidence of potential beneficial, as well as detrimental, effects of both testosterone and oestrogen. We provide a rationale for the necessity to further elucidate sex steroid mechanisms of action at different ages, sexes and brain regions to more fully understand the role of testosterone and oestrogen in the pathophysiology of schizophrenia. The weight of the evidence suggests that sex steroid hormones influence mammalian brain function, including both cognition and emotion, and that pharmaceutical agents aimed at sex steroid receptors appear to provide a novel treatment avenue to reduce symptoms and improve cognition in men and women with schizophrenia.

The pharmacokinetics of racemic MDPV and its (R) and (S) enantiomers in female and male rats.

BACKGROUND: These studies investigated the serum pharmacokinetic (PK) profile of racemic (3,4)-methylenedioxypyrovalerone [(R,S)-MDPV)] and its (R)- and (S)-enantiomers in female and male Sprague Dawley rats. METHODS: Intravenous (R,S)-MDPV (3 and 5.6mg/kg) and single enantiomer of (R)- and (S)-MDPV (1.5mg/kg) were administered to both sexes for PK studies. Intraperitoneal (ip) bioavailability was determined at 3mg/kg (R,S)-MDPV. Locomotor activity studies were conducted after ip treatment with saline and 0.3-5.6mg/kg of (R,S)-MDPV. RESULTS: PK values after iv (R,S)-MDPV showed a significant (p<0.05) sex-dependent differences in the volume of distribution at steady state (Vdss) for (R)- and (R,S)-MDPV at both (R,S)-MDPV doses. The female S/R enantiomeric ratios for area under the concentration time curve (AUCinf) and clearance were significantly lower and higher, respectively, than values determined in males. Importantly, there was no evidence of in vivo inversion of (R)-MDPV or (S)-MDPV to its antipode. There were, however, significant sex-dependent differences in volume of distribution after administration of the (R)-enantiomer. Bioavailability studies of ip (R,S)-MDPV showed greater variability and significantly greater bioavailability in male rats. Accordingly, there was a significantly greater maximal distance traveled measurement in male rats at a 3.0mg/kg dose. CONCLUSION: PK sex differences in (R,S)-MDPV and enantiomers were most apparent in volume of distribution, which could be caused by differences in drug blood and tissue protein binding. The increased magnitude and variance in ip bioavailability in male compared to female rats could lead to sex-dependent differences in the pharmacological action caused by active enantiomer (S)-MDPV.

Chiral determination of 3,4-methylenedioxypyrovalerone enantiomers in rat serum.

The emerging stimulant drug of abuse (3,4)-methylenedioxypyrovalerone [(R,S)-MDPV] is self-administered as a racemic mixture by intranasal, iv, oral, and smoking routes. The individual enantiomers are known to have widely different pharmacological effects, with (S)-MDPV showing much greater potency than (R)-MDPV in pharmacological testing. The goal of these studies was to develop and validate an analytical method for quantitation of (R)-MDPV, (S)-MDPV and (R,S)-MDPV in small volumes of rat serum using a chiral separation column and liquid chromatography-mass spectrometry. The method was validated for selectivity, precision, accuracy, recovery, sensitivity, and reproducibility. The method was also used to determine the enantiomeric stability of the individual enantiomers during sample cleanup and analysis. The linear dynamic range of the calibration curve was 1 - 1000 ng/ml for each enantiomer. Concentration values for the lower limit of quantitation (1 ng/ml) were within 30% of their nominal value, but all other calibration standards were <20% of their nominal value. With proper storage and handling of samples, the two MDPV enantiomers were shown to remain stable in rat serum without any apparent racemization during the time needed for analysis. Finally, the ruggedness of the method was demonstrated with diluted and undiluted serum samples collected from Sprague Dawley rats in a preliminary pharmacokinetic study at 3 mg/kg of (R,S)-MDPV. In summary, the assay used a simple sample preparation method, reversed-phase chiral chromatography, and tandem mass spectrometry to achieve accurate and selective determinations of MDPV enantiomer concentrations in small volumes of serum.

Putative presynaptic dopamine dysregulation in schizophrenia is supported by molecular evidence from post-mortem human midbrain.

The dopamine hypothesis of schizophrenia posits that increased subcortical dopamine underpins psychosis. In vivo imaging studies indicate an increased presynaptic dopamine synthesis capacity in striatal terminals and cell bodies in the midbrain in schizophrenia; however, measures of the dopamine-synthesising enzyme, tyrosine hydroxylase (TH), have not identified consistent changes. We hypothesise that dopamine dysregulation in schizophrenia could result from changes in expression of dopamine synthesis enzymes, receptors, transporters or catabolic enzymes. Gene expression of 12 dopamine-related molecules was examined in post-mortem midbrain (28 antipsychotic-treated schizophrenia cases/29 controls) using quantitative PCR. TH and the synaptic dopamine transporter (DAT) proteins were examined in post-mortem midbrain (26 antipsychotic-treated schizophrenia cases per 27 controls) using immunoblotting. TH and aromatic acid decarboxylase (AADC) mRNA and TH protein were unchanged in the midbrain in schizophrenia compared with controls. Dopamine receptor D2 short, vesicular monoamine transporter (VMAT2) and DAT mRNAs were significantly decreased in schizophrenia, with no change in DRD3 mRNA, DRD3nf mRNA and DAT protein between diagnostic groups. However, DAT protein was significantly increased in putatively treatment-resistant cases of schizophrenia compared to putatively treatment-responsive cases. Midbrain monoamine oxidase A (MAOA) mRNA was increased, whereas MAOB and catechol-O-methyl transferase mRNAs were unchanged in schizophrenia. We conclude that, whereas some mRNA changes are consistent with increased dopamine action (decreased DAT mRNA), others suggest reduced dopamine action (increased MAOA mRNA) in the midbrain in schizophrenia. Here, we identify a molecular signature of dopamine dysregulation in the midbrain in schizophrenia that mainly includes gene expression changes of molecules involved in dopamine synthesis and in regulating the time course of dopamine action.

Pharmacodynamic Relationships between Duration of Action of JDTic-like Kappa-Opioid Receptor Antagonists and Their Brain and Plasma Pharmacokinetics in Rats.

JDTic is a potent and selective κ-opioid receptor (KOR) antagonist that reverses U50,488-induced diuresis in rats. It partitions into brain with a duration of action lasting for weeks. In a search for KOR antagonists that do not accumulate in the brain, we compared single doses of five methylated JDTic analogs (RTI-97, -194, -212, -240, and -241) for reversal of U50,488 diuresis and pharmacokinetic (PK) properties. All six compounds showed potent and selective KOR antagonism in a [35S]GTPγS binding assay. Plasma half-lives ranged from 24 to 41 h and brain half-lives from 24 to 76 h. JDTic and RTI-194 showed increasing brain to plasma ratios over time, indicating increasing partitioning into brain and a longer duration of action for reversal of diuresis than did RTI-97. RTI-240 did not show significant brain accumulation. RTI-212 showed no substantive difference between brain and plasma levels and was inactive against diuresis. RTI-241, with a lower brain to plasma ratio than JDTic and RTI-194, formed JDTic as a metabolite, which still reduced diuresis after 9 weeks. The fact that the duration of action was correlated with the brain to blood plasma ratios and area under the concentration-time curves suggests that PK properties could help to predict safety and acceptable duration of action for KOR antagonists.