CYP2D6 Phenotype Influences Pharmacokinetic Parameters of Venlafaxine: Results from a Population Pharmacokinetic Model in Older Adults with Depression

In this study, we aimed to improve upon a published population pharmacokinetic (PK) model for venlafaxine (VEN) in the treatment of depression in older adults, then investigate whether CYP2D6 metabolizer status affected model-estimated PK parameters of VEN and its active metabolite O-desmethylvenlafaxine. The model included 325 participants from a clinical trial in which older adults with depression were treated with open-label VEN (maximum 300 mg/day) for 12 weeks and plasma levels of VEN and O-desmethylvenlafaxine were assessed at weeks 4 and 12. We fitted a nonlinear mixed-effect PK model using NONMEM to estimate PK parameters for VEN and O-desmethylvenlafaxine adjusted for CYP2D6 metabolizer status and age. At both lower doses (up to 150 mg/day) and higher doses (up to 300 mg/day), CYP2D6 metabolizers impacted PK model-estimated VEN clearance, VEN exposure, and active moiety (VEN + O-desmethylvenlafaxine) exposure. Specifically, compared with CYP2D6 normal metabolizers, (i) CYP2D6 ultra-rapid metabolizers had higher VEN clearance; (ii) CYP2D6 intermediate metabolizers had lower VEN clearance; (iii) CYP2D6 poor metabolizers had lower VEN clearance, higher VEN exposure, and higher active moiety exposure. Overall, our study showed that including a pharmacogenetic factor in a population PK model could increase model fit, and this improved model demonstrated how CYP2D6 metabolizer status affected VEN-related PK parameters, highlighting the importance of genetic factors in personalized medicine.

Drug checking services as a surveillance tool for clinical laboratories: Examining trends in the unregulated fentanyl supply

OBJECTIVES

Timely assessment and understanding of drug trends is essential for clinical laboratories to effectively respond to the overdose epidemic. In this proof-of-concept study, we sought to determine whether information obtained through Toronto's Drug Checking Services (DCS) and cross-provincial urine drug testing (UDT) data can be used as a surveillance tool for clinical laboratories and discuss the value of collaboration between the clinical laboratory, clinicians, and community partners to optimize patient care.

DESIGN & METHODS

Mass spectrometry-based UDT data from LifeLabs Ontario (n = 127,529) and British Columbia (n = 14,848), and drug checking data from Toronto DCS (n = 3,308 drugs or used paraphernalia) was collected between August 2020 and October 2021. Fentanyl co-positivity with toxic adulterants such as benzodiazepine-related drugs and fentanyl analogues were examined.

RESULTS

The percent co-positivity of fentanyl with etizolam, flualprazolam, flubromazolam, carfentanil, and acetylfentanyl in both Ontario UDT and DCS drugs/used paraphernalia showed similar trends. Regional differences in co-positivity with etizolam and fentanyl analogues were noted between Ontario and British Columbia UDT with patterns consistent over the entire 15-month collection period.

CONCLUSIONS

Clinical laboratories should connect with their local DCS, if available, to understand and monitor unregulated drug trends. These data can be used as an important tool to help clinical laboratories tailor their UDT menus and thereby provide a community-focused service to improve patient care.

Emerging synthetic cannabinoids detected by a drug checking service in Toronto, Canada

BACKGROUND

Toronto's Drug Checking Service (DCS) provides people who use drugs with information on the chemical composition of their substances and conducts real-time monitoring of the unregulated drug supply. Presented are first known data of three newly detected synthetic cannabinoids (SCs) in Toronto, Ontario.

METHODS

The present data are from samples analyzed between April and November 2020. Samples were collected at partnering harm reduction agencies in Toronto and analyzed using gas or liquid chromatography-mass spectrometry. An intake survey queried about the sample characteristics on submission, including expected drug(s).

RESULTS

Samples were analyzed between 1 April and 20 November 2020 (N = 19), which marks the period immediately following imposed COVID-19 border and movement restrictions in Canada. The newly detected, unexpected SCs were ACHMINACA (n = 15), AB-FUBINACA (n = 3), and 4-fluoro-MDMB-BUTINACA (n = 1). Fentanyl was expected in 74% (n = 14). Most SCs were detected in samples containing fentanyl or related analogues (n = 18; 95%), or benzodiazepine-related drugs (i.e., etizolam and flualprazolam) (n = 15; 79%).

CONCLUSIONS

This information can inform overdose prevention efforts and drug market monitoring of SCs in Toronto and regions served by the same drug trafficking routes. The detection of SCs during a period marked by COVID-19-related restrictions can contribute to efforts to identify global drug market trends during this time.

Combined effect of alcohol and cannabis on simulated driving

RATIONALE

With alcohol and cannabis remaining the most commonly detected drugs in seriously and fatally injured drivers, there is a need to understand their combined effects on driving.

OBJECTIVES

The present study examined the effects of combinations of smoked cannabis (12.5% THC) and alcohol (target BrAC 0.08%) on simulated driving performance, subjective drug effects, cardiovascular measures, and self-reported perception of driving ability.

METHODS

In this within-subjects, double-blind, double-dummy, placebo-controlled, randomized clinical trial, cannabis users (1-7 days/week) aged 19-29 years attended four drug administration sessions in which simulated driving, subjective effects, cardiovascular measures, and whole blood THC and metabolite concentrations were assessed following placebo alcohol and placebo cannabis (<0.1% THC), alcohol and placebo cannabis, placebo alcohol and active cannabis, and alcohol and active cannabis.

RESULTS

Standard deviation of lateral position in the combined condition was significantly different from the placebo condition (p < 0.001). Standard deviation of lateral position was also significantly different from alcohol and cannabis alone conditions in the single task overall drive (p = 0.029 and p = 0.032, respectively), from the alcohol alone condition in the dual task overall drive (p = 0.022) and the cannabis alone condition in the dual task straightaway drive (p = 0.002). Compared to the placebo condition, the combined and alcohol conditions significantly increased reaction time. Subjective effects in the combined condition were significantly greater than with either of the drugs alone at some time points, particularly later in the session. A driving ability questionnaire showed that participants seemed unaware of their level of impairment.

CONCLUSION

Combinations of alcohol and cannabis increased weaving and reaction time, and tended to produce greater subjective effects compared to placebo and the single drug conditions suggesting a potential additive effect. The fact that participants were unaware of this increased effect has important implications for driving safety.

Diverse psychotropic substances detected in drug and drug administration equipment samples submitted to drug checking services in Toronto, Ontario, Canada, October 2019-April 2020

BACKGROUND

The overdose crisis has generated innovative harm reduction and drug market monitoring strategies. In Toronto, Ontario, Canada, a multi-site drug checking service (DCS) pilot project was launched in October 2019. The project provides people who use drugs with information on the chemical composition of their substances, thereby increasing their capacity to make more informed decisions about their drug use and avoid overdose. DCS also provides real-time market monitoring to identify trends in the unregulated drug supply.

METHODS

Sample data were obtained through analyses of drug and used drug administration equipment samples submitted anonymously and free of charge to DCS in downtown Toronto from October 10, 2019, to April 9, 2020, representing the first six months of DCS implementation. Analyses were conducted in clinical laboratories using liquid chromatography- and/or gas chromatography-mass spectrometry (LC-MS, GC-MS) techniques.

RESULTS

Overall, 555 samples were submitted, with 49% (271) of samples that were found to contain high-potency opioids, of which 87% (235) also contained stimulants. Benzodiazepine-type drugs were found in 21% (116) of all samples, and synthetic cannabinoids in 1% (7) of all samples. Negative effects (including overdose, adverse health events, and extreme sedation) were reported for 11% (59) of samples submitted for analysis.

CONCLUSIONS

Toronto's DCS identified a range of high-potency opioids with stimulants, benzodiazepine-type drugs, and a synthetic cannabinoid, AMB-FUBINACA. This information can inform a range of evidence-informed overdose prevention efforts.

Xylazine detected in unregulated opioids and drug administration equipment in Toronto, Canada: clinical and social implications

BACKGROUND

The North American opioid overdose crisis is driven in large part by the presence of unknown psychoactive adulterants in the dynamic, unregulated drug supply. We herein report the first detection of the psychoactive veterinary compound xylazine in Toronto, the largest urban center in Canada, by the city's drug checking service.

METHODS

Toronto's Drug Checking Service launched in October 2019. Between then and February 2021, 2263 samples were submitted for analysis. The service is offered voluntarily at harm reduction agencies that include supervised consumption services. Samples were analyzed using gas chromatography-mass spectrometry or liquid chromatography-high resolution mass spectrometry. Targeted and/or untargeted screens for psychoactive substances were undertaken.

RESULTS

In September 2020, xylazine was first detected by Toronto's Drug Checking Service. Among samples analyzed from September 2020 to February 2021 expected to contain fentanyl in isolation (610) or in combination with methamphetamine (16), xylazine was detected in 46 samples (7.2% and 12.5% of samples, respectively). Samples were predominantly drawn from used drug equipment. Three of the samples containing xylazine (6.5%) were associated with an overdose.

CONCLUSION

We present the first detection of xylazine in Toronto, North America's fourth-largest metropolitan area. The increased risk of overdose associated with use of xylazine and its detection within our setting highlights the importance of drug checking services in supporting rapid responses to the emergence of potentially harmful adulterants. These data also highlight the clinical challenges presented by the dynamic nature of unregulated drug markets and the concomitant need to establish regulatory structures to reduce their contribution to overdose morbidity and mortality.

Impaired awareness: Why people with multiple sclerosis continue using cannabis despite evidence to the contrary

BACKGROUND

With widespread moves toward legalization of cannabis, increasing numbers of people with multiple sclerosis (pwMS) are using the drug. Emerging MS-related data show that cannabis can cause or exacerbate cognitive dysfunction.

OBJECTIVE

To understand why people with MS continue using cannabis despite adverse cognitive consequences. It was hypothesized that lack of awareness, a component of metacognition, could explain this decision, in part.

METHOD

Forty pwMS who smoked cannabis almost daily were assigned by odd-even case number selection to either a cannabis continuation (CC) or cannabis withdrawal (CW) group. Both groups were followed for 28 days. All participants completed, at baseline and day 28, the brief repeatable battery of neuropsychological tests (BRNB) in MS for measures of processing speed, memory and executive function; Modified fatigue impact scale (mFIS) for self-report indices of cognitive functioning.

RESULTS

No significant baseline differences between the groups on the BRNB and mFIS. At day 28, significant improvement within group was seen on all measures of the BRNB, but only in the CW group (p = .0001 for all indices). A repeat measure ANOVA did not find any significant group (CC vs. CW) × time (baseline and day 28) interactions for the self-report cognitive measures on the mFIS. Cannabis abstainers did report less ability to function away from home. All 19 participants in the CW group reverted to using cannabis on study completion despite being informed individually of their cognitive improvement.

CONCLUSIONS AND RELEVANCE

The inability of pwMS to accurately appraise their memory and executive function can help explain, in part, why they continue to smoke cannabis despite objective evidence of the deleterious cognitive side effects of this behavior.

Detection of synthetic cannabinoid adulteration in the unregulated drug supply in three Canadian settings

INTRODUCTION

Novel psychoactive substances (NPS) are increasingly being consumed worldwide, with synthetic cannabinoids and synthetic opioids being the second and third most commonly used NPS, respectively. Certain synthetic cannabinoids can produce significant harms, particularly when used with opioids. The objective of this study was to characterise the presence of synthetic cannabinoids in the unregulated drug supply in three Canadian settings METHODS: In the British Columbia setting, all samples were first analysed at point-of-care using combination Fourier-transform infrared (FTIR) spectroscopy and fentanyl immunoassay strips prior to confirmatory testing using quantitative nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry (GC/MS) and/or liquid chromatography/mass spectrometry (LC/MS). In the Toronto, Ontario setting, the samples were analysed directly by GC/MS, LC/MS liquid chromatography-high resolution/mass spectrometry.

RESULTS

Between January 2018 and December 2019, 38 (2.8%) synthetic cannabinoid samples were detected in the unregulated drug supply (25/909 in British Columbia and 13/440 in Ontario). In British Columbia and Ontario, 76% and 85% of samples, respectively, were expected by individuals to be an opioid. Synthetic cannabinoids detected included AMB-FUBINACA, AB-FUBINACA, 5-fluoro-MDMB-PINACA, and 5-fluoro-MDMB-PICA, and largely co-occurred with fentanyl. In the British Columbia context, Fourier-transform infrared spectroscopy failed to detect synthetic cannabinoid compounds in almost half (48%) of the samples at point-of-care.

DISCUSSION AND CONCLUSIONS

As point-of-care technologies failed to detect these compounds in many occasions, our findings demonstrate the importance of laboratory confirmatory analysis to identify NPS. Given the high risk of harm associated with the consumption of synthetic cannabinoids, further research should investigate the reasons for adulteration.

Discontinuing cannabis improves depression in people with multiple sclerosis: A short report

To assess whether symptoms of depression change when people with multiple sclerosis (pwMS) discontinue cannabis use, 40 cognitively impaired pwMS who smoked cannabis almost daily were randomly assigned to either a cannabis continuation (CC) or cannabis withdrawal (CW) group. Both groups were followed for 28 days. All participants completed the Hospital Anxiety and Depression Scale. At day 28 the 11-nor-9-carboxy-Δ⁹-tetrahydro-cannabinol (THCCOOH)/creatinine ratio in the CW group declined to zero (p = 0.0001), but remained unchanged in the CC group (p = 0.709). Depression scores in those pwMS who were using cannabis to manage their depression remained statistically unchanged in the CC group, but declined in the CW group (p = 0.006). Despite pwMS using cannabis to help their mood, depression improved significantly off the drug. Our finding provides a cautionary note in relation to cannabis use in pwMS, at least with respect to depression.

Multimodal MRI Longitudinal Assessment of White and Gray Matter in Different SPG Types of Hereditary Spastic Paraparesis

Hereditary spastic paraplegias (HSP) are a group of genetically and clinically heterogeneous neurologic disorders. Hereby we describe a relatively large group of patients (pts) affected by HSP studied at baseline (31 pts) and at follow-up (mean period 28.9 ± 8.4 months; 23 pts) with multimodal advanced MRI: high-resolution T1 images for voxel-based morphometry (VBM) analysis, magnetic resonance spectroscopy (MRS), and diffusion tensor imaging (DTI). An age-matched healthy control (HC) group underwent the same neuroimaging protocol in a time schedule matched with the HSP patients. At baseline, VBM showed gray matter (GM) reduction in HSP in the right pre-frontal cortex and bilaterally in the thalami. MRS at baseline depicted in HSP patients compared to the HC group reduction of NAA/Cr ratio in the right pre-frontal region, increase of Cho/Cr ratio in the right pre-central regions, and increase of mI/Cr ratio on the left pre-central area. At cross-sectional follow-up analysis and longitudinal evaluation, no VBM and MRS statistically significant results were obtained. Tract-based spatial statistics (TBSS) analysis showed widespread DTI brain white matter (WM) alterations in patients compared to HC at baseline, which are characterized by reduction of fractional anisotropy (FA) and increase of mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity, as confirmed on cross-analysis of the follow-up dataset. A longitudinal analysis with TBSS in HSP patients did not show significant variations, while upon applying region-based analysis we found increased FA and decreased MD and AD in specific brain WM fiber complex during follow-up. The changes were not correlated with the clinical presentation (pure vs complicated HSP), motor function, and motility indexes or history of specific treatments (botulinum toxin). In conclusion, the cross-sectional analysis of the multiparametric MRI data in our HSP patients confirmed the non-prominent involvement of the cortex in the primary motor regions but rather of other more associative areas. On the contrary, DTI demonstrated a widespread involvement of the brain WM, including the primary motor regions, which was confirmed at follow-up. The longitudinal analysis revealed an apparent inversion of tendency when considering the expected evolution of a neurodegenerative process: we detected an increase of FA and a decrease of MD and AD. These time-related modifications may suggest a repair attempt by the residual central WM fibers, which requires confirmation with a larger group of patients and with a longer time interval.

Coming off cannabis: a cognitive and magnetic resonance imaging study in patients with multiple sclerosis

Cognitive dysfunction affects 40-80% of patients with multiple sclerosis. Smoking cannabis may add to these deficits. It is unclear whether coming off cannabis results in cognitive improvement. To address this question, 40 patients with multiple sclerosis who started using cannabis after the onset of multiple sclerosis and who used it for at least 4 days a week over many years were divided by odd-even number selection into two groups: cannabis continuation and cannabis withdrawal. Assessments took place at baseline and after 28 days and included serial versions of the Brief Repeatable Neuropsychological Battery for multiple sclerosis containing tests of verbal and visual memory, processing speed and executive function; structural and functional MRI, the latter entailing a compatible version of the Symbol Digit Modalities Test; urine for cannabinoid metabolites to detect compliance with abstinence. Only those participants deemed globally impaired at baseline (failure on at least two cognitive domains) were enrolled. The results revealed that the two groups were well matched demographically and neurologically. One subject was removed from the withdrawal group because of failed abstinence. Urine analysis revealed the cannabinoid consumed was predominantly tetrahydrocannabinol (THC). There were no baseline between group cognitive differences, but by Day 28 the withdrawal group performed significantly better on every cognitive index (P < 0.0001 for all). Significant within group differences were present for every test over time, but only in the abstinent group (P < 0.0001 for all tests). There were no between group baseline or Day 28 differences in structural MRI indices (global atrophy, total T1 and T2 lesion volume). At index assessment the two groups had a similar performance on the functional MRI-compatible Symbol Digit Modalities Test and there were no group differences in brain activation. However, by Day 28, the withdrawal group completed more trials correctly (P < 0.012) and had a faster reaction time (P < 0.002), associated with significantly increased activation in brain regions known to be associated with performance of the test (bilateral inferior frontal gyri, caudate and declive/cerebellum, P < 0.001 for all regions). These results reveal that patients with multiple sclerosis who are frequent, long-term cannabis users can show significant improvements in memory, processing speed and executive function after 28 days of drug abstinence. The absence of similar improvements in a matched multiple sclerosis group that remained on cannabis shows that beneficial cognitive change after stopping cannabis is not solely attributable to the effects of practice.

Evaluating networked drug checking services in Toronto, Ontario: study protocol and rationale

BACKGROUND

The increasing incidence of fatal opioid overdose is a public health crisis in Canada. Given growing consensus that this crisis is related to the presence of highly potent opioid adulterants (e.g., fentanyl) in the unregulated drug supply, drug checking services (DCS) have emerged as part of a comprehensive approach to overdose prevention. In Canada's largest city, Toronto, a network of DCS launched in 2019 to prevent overdose and overdose-related risk behaviors. This network employs mass spectrometry technologies, with intake sites co-located with supervised consumption services (SCS) at three frontline harm reduction agencies. The protocol and rationale for assessing the impact of this multi-site DCS network in Toronto is described herein. The aims of this study are to (1) evaluate the impact of DCS access on changes in and factors influencing overdose and related risk behaviors, (2) investigate the perceived capacity of DCS to prevent overdose, and (3) identify composition (qualitative and quantitative) trends in Toronto's unregulated drug supply.

METHODS

We will use a parallel-mixed-methods design with complementary data sources (including data from chemical analysis of drug samples, quantitative intake and post-test surveys, SCS, coroners, paramedic services, and qualitative interviews), followed by a meta-inference process wherein results from analyses are synthesized.

RESULTS

Whereas most DCS globally target "recreational drug users," in Toronto, this networked DCS will primarily target marginalized people who use drugs accessing frontline services, many of whom use drugs regularly and by injection. This evolution in the application of DCS poses important questions that have not yet been explored, including optimal service delivery models and technologies, as well as unique barriers for this population. Increasing information on the unregulated drug supply may modify the risk environment for this population of people who use drugs.

CONCLUSIONS

This study addresses evidence gaps on the emerging continuum of overdose prevention responses and will generate critical evidence on a novel approach to reducing the ongoing high incidence of drug-related morbidity and mortality in Canada and elsewhere.

Acute and residual effects of smoked cannabis: Impact on driving speed and lateral control, heart rate, and self-reported drug effects

BACKGROUND

Although driving under the influence of cannabis is increasingly common among young adults, little is known about residual effects on driver behavior. This study examined acute and residual effects of smoked cannabis on simulated driving performance of young cannabis users.

METHODS

In this double-blind, placebo-controlled, parallel-group randomized clinical trial, cannabis users (1-4 days/week) aged 19-25 years were randomized with a 2:1 allocation ratio to receive active (12.5% THC) or placebo (0.009% THC) cannabis in a single 750 mg cigarette. A median split (based on whole-blood THC concentrations at the time of driving) was used to divide the active group into low and high THC groups. Our primary outcome was simulated driving performance, assessed 30 min and 24 and 48 h after smoking. Secondary outcomes included blood THC concentrations, subjective drug effects, and heart rate.

RESULTS

Ninety-six participants were randomized, and 91 were included in the final analysis (30 high THC, 31 low THC, 30 placebo). Mean speed (but not lateral control) significantly differed between groups 30 min after smoking cannabis (p ≤ 0.02); low and high THC groups decreased their speed compared to placebo. Heart rate, VAS drug effect and drug high increased significantly immediately after smoking cannabis and declined steadily after that. There was little evidence of residual effects in any of the measures.

CONCLUSION

Acutely, cannabis caused decreased speed, increased heart rate, and increases in VAS drug effect and drug high. There was no evidence of residual effects on these measures over the two days following cannabis administration.

Predicting Escitalopram Exposure to Breastfeeding Infants: Integrating Analytical and In Silico Techniques

BACKGROUND

Escitalopram is used for post-partum depression; however, there are limited pharmacokinetic data of escitalopram in milk and plasma of infants breastfed by women taking the drug.

OBJECTIVE

The objective of this study was to apply physiologically-based pharmacokinetic (PBPK) modelling to predict infant drug exposure (plasma area under the curve from time zero to infinity [AUC_∞]) based on drug monitoring data of escitalopram in breast milk.

METHODS

Using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, we quantified escitalopram concentrations in milk samples of 18 breastfeeding women with escitalopram therapy at steady state, collected at three to five time points. The escitalopram concentrations in breast milk were used with infant feeding parameters from the literature to simulate infant daily dose. We used PK-Sim^® to develop an adult PBPK model for escitalopram and extrapolated it to a population of 1600 infants up to 12 months of age. An integration of the simulated infant daily dose and the virtual infants with variable physiological-pharmacological parameters was used to predict drug exposure (plasma AUC_∞) distribution in the population of infants breastfed by women receiving escitalopram 20 mg/day.

RESULTS

Escitalopram concentrations in milk were 50 ± 17 ng/mL (mean ± standard deviation). The simulated infant plasma AUC_∞ following escitalopram exposure through breast milk was low, with a median of 1.7% (range 0.5-5.9%) of the corresponding maternal plasma AUC_∞, indicating no substantial exposure.

CONCLUSIONS

Infant exposure levels to escitalopram in breast milk are low. A PBPK modeling approach can be used to translate data on drug monitoring in milk into a population distribution of infant plasma levels for drug safety assessment.

A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls

BACKGROUND

Cannabis use disorders (CUD) are common in schizophrenia (~25%) compared to the general population (~3%). Tetrahydrocannabinol (THC), the principal psychoactive component in cannabis is fat-soluble, resulting in an extended period for cannabinoid elimination. While detection of cannabinoids in urine is indicative of prior cannabis exposure, time of last use is difficult to verify sustained abstinence for extended periods (e.g., 28-days) in chronic cannabis users. Therefore, we evaluated the utility of a sustained cannabis abstinence paradigm in patients with schizophrenia and non-psychiatric controls.

METHODS

Cannabis dependent patients (n=19) and controls (n=20) underwent 28-days of monitored cannabis abstinence facilitated with contingency management. Urine samples were taken twice weekly. Abstinence was evaluated using 1) Self-report; 2) Qualitative biochemical confirmation using MEDTOX; and 3) in a subset of participants (schizophrenia, n=13; controls, n=13) gas chromatography-mass spectrometry (GC-MS) was performed to obtain quantitative creatinine-normalized carboxy-THC (THC-COOH) metabolite levels <20ng/mL). Subjective assessments were used to assess behavioral correlates of cannabis abstinence and further supported time-dependent abstinence trajectories.

RESULTS

Abstinence rates of 42.1% (8/19) in patients and 55% (11/19) in controls (p=0.53) were observed. Increased cannabis withdrawal symptoms in both patients and controls supported abstinence.

DISCUSSION

Our results suggest a feasible method for identification of short-term cannabis abstinence in individuals with schizophrenia at rates comparable to controls. Monitoring sustained abstinence may have implications for potential interventions for CUDs in schizophrenia.

The effects of buspirone on occupancy of dopamine receptors and the rat gambling task

BACKGROUND

The dopamine D3 receptor (DRD₃) has been proposed as a target for drug development for the treatment of addictive disorders. Recently, the anxiolytic buspirone has been shown to have affinity for DRD₃ and DRD₄, and interest in repurposing it for addictive disorders has grown.

METHODS

Binding of [³H]-(+)-PHNO in the rat cerebellum and striatum was used to measure occupancy by buspirone of DRD₃ or DRD₂, respectively. Effects of buspirone in the rat gambling task (rGT) and the five-choice serial reaction time task (5-CSRTT) were examined.

RESULTS

Buspirone occupied both the DRD₂ and DRD₃ at high doses and the DRD₃, but not the DRD₂, in the narrow dose range of 3 mg/kg. At 10 mg/kg, a disruption of performance on rGT was observed. All measures of performance on the rGT, except for perseverations, were affected at 3 mg/kg. On the 5-CSRTT, omissions were increased. Impairments in the rGT were not mimicked by the effects induced by satiation. Further, buspirone did not impair food-maintained responding under a progressive ratio schedule of reinforcement at any dose, suggesting that the effects of buspirone on the rGT cannot be explained by non-selective actions.

CONCLUSIONS

Although buspirone had effects on the rGT at the dose that selectively occupied the DRD₃, the effects found do not parallel those found in previous studies of the effects of selective DRD₃ antagonists on the rGT. Thus, buspirone may impair performance on the rGT through actions at multiple receptor sites.

Carbohydrate intake, obesity, metabolic syndrome and cancer risk? A two-part systematic review and meta-analysis protocol to estimate attributability

INTRODUCTION

Linkages between carbohydrates, obesity and cancer continue to demonstrate conflicting results. Evidence suggests inconclusive direct linkages between carbohydrates and specific cancers. Conversely, obesity has been strongly linked to a wide range of cancers. The purpose of the study is to explore linkages between carbohydrate intake and cancer types using a two-step approach. First the study will evaluate the linkages between carbohydrate intake and obesity, potentially stratified by metabolic syndrome status. Second, the estimated attributable fraction of obesity ascribed to carbohydrate intake will be multiplied against obesity attributable fractions for cancer types to give estimated overall attributable fraction for carbohydrate versus cancer type.

METHODS AND ANALYSIS

We will perform a comprehensive search to identify all possible published and unpublished studies that have assessed risk factors for obesity including dietary carbohydrate intake. Scientific databases, namely PubMed MEDLINE, EMBASE, EBSCOhost and ISI Web of Science will be searched. Following study selection, paper/data acquisition, and data extraction and synthesis, we will appraise the quality of studies and risk of bias, as well as assess heterogeneity. Meta-weighted attributable fractions of obesity due to carbohydrate intake will be estimated after adjusting for other potential confounding factors (eg, physical inactivity, other dietary intake). Furthermore, previously published systematic reviews assessing the cancer-specific risk associated with obesity will also be drawn. These estimates will be linked with the attributability of carbohydrate intake in part 1 to estimate the cancer-specific burden that can be attributed to dietary carbohydrates. This systematic review protocol has been developed according to the 'Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) 2015'.

ETHICS AND DISSEMINATION

The current study will be based on published literature and data, and, as such, ethics approval is not required. The final results of this two part systematic review (plus multiplicative calculations) will be published in a relevant international peer-reviewed journal.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42015023257.

Electromyographic and laboratory findings in acute Solanum torvum poisoning

CONTEXT

Solanum torvum berries, known as susumber or turkey berries, are prepared as part of traditional Jamaican dishes usually served with cod and rice. Poisoning is rare. Although toxic compounds have never been definitively isolated, previous reports suggest toxicity results from inhibition of acetylcholinesterases. We present a case of susumber berry poisoning with detailed electromyographic studies and laboratory analysis.

CASE DETAILS

A 54-year-old woman presented to the Emergency Department (ED) complaining of vision, speech, and gait changes; emesis; and diffuse myalgias following consumption of susumber berries. The physical examination demonstrated an intact, lucid mental status, miosis, opsoclonus, severe dysarthria, dysmetria, mild extremity tenderness and weakness, and inability to ambulate. Her symptom constellation was interpreted as a stroke.

DISCUSSION

Electromyography demonstrated a pattern of early full recruitment as well as myotonia during the period of acute toxicity. Additionally, solanaceous compounds, in particular solasonine and solanidine, were identified in leftover berries and the patient's serum. Store-bought commercial berries and subsequent serum samples were free of such toxic compounds. EMG studies, together with a laboratory analysis of berries or serum can assist in the differential diagnosis of stroke, and provide both a prognostic screening and confirmation of suspected glycoside toxicity.

Nicotine metabolite ratio (3-hydroxycotinine/cotinine) in plasma and urine by different analytical methods and laboratories: implications for clinical implementation

BACKGROUND

The highly genetically variable enzyme CYP2A6 metabolizes nicotine to cotinine (COT) and COT to trans-3'-hydroxycotinine (3HC). The nicotine metabolite ratio (NMR, 3HC/COT) is commonly used as a biomarker of CYP2A6 enzymatic activity, rate of nicotine metabolism, and total nicotine clearance; NMR is associated with numerous smoking phenotypes, including smoking cessation. Our objective was to investigate the impact of different measurement methods, at different sites, on plasma and urinary NMR measures from ad libitum smokers.

METHODS

Plasma (n = 35) and urine (n = 35) samples were sent to eight different laboratories, which used similar and different methods of COT and 3HC measurements to derive the NMR. We used Bland-Altman analysis to assess agreement, and Pearson correlations to evaluate associations, between NMR measured by different methods.

RESULTS

Measures of plasma NMR were in strong agreement between methods according to Bland-Altman analysis (ratios, 0.82-1.16) and were highly correlated (all Pearson r > 0.96, P < 0.0001). Measures of urinary NMR were in relatively weaker agreement (ratios 0.62-1.71) and less strongly correlated (Pearson r values of 0.66-0.98, P < 0.0001) between different methods. Plasma and urinary COT and 3HC concentrations, while weaker than NMR, also showed good agreement in plasma, which was better than that in urine, as was observed for NMR.

CONCLUSIONS

Plasma is a very reliable biologic source for the determination of NMR, robust to differences in these analytical protocols or assessment site.

IMPACT

Together this indicates a reduced need for differential interpretation of plasma NMR results based on the approach used, allowing for direct comparison of different studies.

[Changes in corneal thickness in glaucoma]

It is a clinical, observational, retrospective, randomised study, performed on 46 eyes. We have evaluated the effects of some of the drugs used to treat glaucoma (prostaglandine analogues, beta blockers, carbonic anhydrase inhibitors) on the central corneal thickness.

[Corneal endothelium in glaucoma]

It is a clinical, observational, retrospective, randomised study, performed on 34 eyes with hipertensive primary open angle glaucoma (POAG) drug equilibrated and 18 eyes with normotensive POAG. We have evaluated the endothelial cells number variation in the hypertensive POAG and normotensive POAG.

The heat shock protein 90 inhibitor IPI-504 induces KIT degradation, tumor shrinkage, and cell proliferation arrest in xenograft models of gastrointestinal stromal tumors

The activity of the receptor tyrosine kinase KIT is crucial for gastrointestinal stromal tumor (GIST) growth and survival. Imatinib and sunitinib are very effective in advanced GIST, but have no curative potential. The observation that heat shock protein 90 (HSP90) inhibition results in KIT degradation prompted us to assess the efficacy of the HSP90 inhibitor retaspimycin hydrochloride (IPI-504) alone or in combination with imatinib or sunitinib in two GIST xenografts with distinctive KIT mutations. Nude mice were grafted with human GIST carrying KIT exon 13 (GIST-882; n = 59) or exon 11 (GIST-PSW; n = 44) mutations and dosed with imatinib (50 mg/kg twice daily), sunitinib (40 mg/kg once daily), IPI-504 (100 mg/kg 3 times per week), IPI-504 + imatinib, or IPI-504 + sunitinib. We evaluated tumor volume, proliferation and apoptosis, KIT expression and activation, as well as adverse events during treatment. Treatment with IPI-504 alone resulted in tumor regression, proliferation arrest, and induction of tumor necrosis. We documented downregulation of KIT and its signaling cascade in IPI-504-treated animals. Treatment effects were enhanced by combining IPI-504 with imatinib or sunitinib. On histologic examination, liver damage was frequently observed in animals exposed to combination treatments. In conclusion, IPI-504 shows consistent antitumor activity and induces KIT downregulation in GIST, as a single agent, and is more potent in combination with imatinib or sunitinib. The sequence of drug administration in the combination arms warrants further studies.

Impact of the HIV epidemic and Anti-Retroviral Treatment policy on lymphoma incidence and subtypes seen in the Western Cape of South Africa, 2002-2009: preliminary findings of the Tygerberg Lymphoma Study Group

The Tygerberg Lymphoma Study Group was constituted in 2007 to quantify the impact of HIV on the pattern and burden of lymphoma cases in the Western Cape of South Africa which currently has an HIV prevalence of 15%. South Africa has had an Anti-Retroviral Treatment (ART) policy and a roll-out plan since 2004 attaining 31% effective coverage in 2009. This study is designed to qualify and establish the impact of HIV epidemic and the ARV roll-out treatment program on the incidence of HIV Related Lymphoma (HRL). Early data document that despite the ART roll out, cases of HRL are increasing in this geographical location, now accounting for 37% of all lymphomas seen in 2009 which is an increase from 5% in 2002. This is in contrast to trends seen in developed environments following the introduction of ART. Also noted are the emergence of subtypes not previously seen in this location such as Burkitt and plasmablastic lymphomas. Burkitt lymphoma is now the commonest HRL seen in this population followed by diffuse large B-cell lymphoma subtypes. The reasons for this observed increase in HRL are not ascribable to improved diagnostic capacity as the tertiary institute in which these diagnoses are made has had significant expertise in this regard for over a decade. We ascribe this paradoxical finding to an ART treatment environment that is ineffective for a diversity of reasons, paramount of which are poor coverage, late commencement of ART and incomplete viral suppression.

[Advances in preservative-free glaucoma drops]

Ophthalmic solutions are the main therapeutic methods used in the treatment of ocular diseases, including glaucoma. Preservatives are added in multidose solutions to reduce the risk of microbial contamination. Repeated use of topical medication, especially in patients treated for glaucoma, has many adverse effects especially on the ocular surface. This paper provides an overview of the role of preservatives in antiglaucoma preparations, and their impact on the ocular surface.

[Fixed combination of topical prostaglandin analogue in glaucoma treatment]

The purpose of glaucoma treatment is to prevent progressive loss of optic nerve fibers and thereby to preserve the visual field. Because increased IOP is a primary risk factor in developing glaucoma, descrease its value below which may affect the optic is the antiglaucoma treatment target. This paper provides an overview of glaucoma treatment and the use of fixed combinations of topical prostaglandin analogues (PGA).

[Glaucoma and ocular surface]

Topical eye-drops remain the cornerstone of treatment for ocular diseases, including glaucoma. Preservatives are added to multi-dose medication bottles to reduce the risk of microbial contamination, to extend the validity of the product and to allow an easily use of the bottles. However the repetitious use of ophthalmic medications containing preservatives, particularly when treating chronic diseases, has been linked to adverse effects and ocular surface disease (OSD). Therefore, this presentation provides an overview of glaucoma and OSD, the role of preservatives in ophthalmic preparations, and the impact of preservatives on the ocular surface.

[About ocular surface damage]

Tear film maintain ocular surface health and functional through nutritional support, anti-bacterial properties, viscoelastic protection, smooth optical surface and increase of lubrication. The ocular surface may be affected after surgery (cataract, glaucoma, refractive surgery) or chronic glaucoma treatment.

[Progresses in antiinflamatory treatment in cataract surgery]

Anti-inflamatory medication is commonly used to reduce inflammation, edema and symptoms associated with allergies, trauma and infections diseases. Topical nonsteroidial anti-inflammatory (NSAIDs) and topical corticosteroids are overview of the role of topical NSAIDs and the progress of their use in eye surgery

[Increased ocular perfusion--visual field preservation]

Adjustment of the ocular flow has clear implications in glaucomatous pathology. It cannot be drawn a clear barrier between causality and effect of ocular vascular factor in glaucoma but altered hemodynamics leads clearly to node loss. Unstable ocular perfusion creates a low blood flow to the optic nerve directly involved in glaucomatous optic neuropathy , ocular perfusion pressure (PPO) being a risk factor predictor of progression associated with impairment of visual function in glaucoma.

[Alternative treatments in glaucoma, independent from ocular pressure]

Glaucoma is a medical condition that affects the optic nerve of the eye and can lead to a permanent loss of vision if left untreated. It is now clear that IOP (intraocular pression) lowering treatment may significantly delay or prevent glaucoma development and progression. Although current ocular hypotensive therapy is generally considered safe, alternative treatments may also be considered to slow the progression and prevent the development of complications of the disease.

[Extract of Ginkgo biloba in glaucoma]

Protective and curative effects of the ginkgo biloba extract are known for a long time and confirmed the practical reality. Its main benefit is due to its antioxidant properties, manifested by activation of free radicals by flavonoids contained in gingko by binding free radicals.

[Refractive stability of artificial crystallins--acrysof TORIC]

PURPOSE

To evaluate the results of AcrySof Toric intraocular lens (Alcon) implantation to correct pre-existing astigmatism and rotational stability in patients having cataract surgery or not.

METHODS

Retrospective study three surgical teams, between February 2009-August 2010, included 37 eyes with more than 1 diopter (D) of preexisting corneal astigmatism having or not cataract surgery.

RESULTS

Rotation at 6 M post-op: 32 patients (87%)--> rotation between aprox. 0-5 degrees, 4 patients (11%)--> rotation between A 5-10 degrees, 1 patient (2%) rotation of A 20 degrees. The mean refractive cylinder decreased significantly after surgery: 34 (91.90%) of cases between 0.25-0.75 D--2 (5.40%) of cases 1.5 D--1 (2.70%) of cases > 1.5 D.

CONCLUSIONS

In conclusion the results indicate that TheAcrySof Toric IOL is a viable option of preoperative corneal astigmatism in carefully selected cases. The Toric IOL showed good rotational stability The most frequent cause of turnover is the: viscoelastic left in the capsular bag (early rotation); fibrosis of the bag (late rotation).

[Neuroprotection in glaucoma]

The present paper is a revue of the basic terms related to the neuroprotection, an up-to-date on the pathophysiology of glaucoma. There are emphasized some of the main directions of evolution in the antiglaucomatous and neuroprotective treatment.

[Cornea in glaucoma]

The authors present a clinical, observational, retrospective, randomized study, performed between 06.01-01.05.2010, on 84 eyes. We have followed the changes of corneal endothelial cell density in patients with primary hypertensional open angle glaucoma, treated using the same therapeutic method, with compensated, undercompensated and decompensated IOP.

High efficacy of panobinostat towards human gastrointestinal stromal tumors in a xenograft mouse model

PURPOSE

Histone deacetylase inhibitors have emerged as potent anticancer compounds. Using a nude-mouse xenograft model, for the first time we evaluated the response of human gastrointestinal stromal tumors (GIST) carrying different oncogenic KIT mutations to panobinostat (LBH589), administered single or in combination with imatinib.

EXPERIMENTAL DESIGN

We grafted the human GIST882 cell line with KIT exon 13 mutation and two biopsies from patients radiologically progressing under imatinib showing KIT exon11 and KIT exon9 mutations, respectively. Our study included 4 groups: A (n = 9; control), B (n = 10; panobinostat 10 mg/kg daily, i.p.), C (n = 9; imatinib 150 mg/kg bidaily, p.o), and D (n = 8; combination panobinostat-imatinib, same dose/schedule as above). Treatment lasted 12 days. Tumor size was measured regularly using standard variables. Histopathological assessment was by H&E, and immunohistochemically with KIT, cleaved caspase-3, Ki-67, and histone acetylation staining.

RESULTS

Overall, GIST xenografts responded rapidly to panobinostat as indicated by tumor regression, necrosis, hemorrhages, fibrosis, and/or myxoid degeneration, remarkable apoptosis, and substantial decline of cell proliferation. H3 and H4 acetylation increased significantly from control level in all treated groups. The combination of panobinostat and imatinib further enhanced most of the assessed parameters.

CONCLUSIONS

We show for the first time potential therapeutic activity of panobinostat in human GISTs, in vivo. Our results warrant further exploration of histone deacetylase inhibitors for the treatment of advanced GISTs. Our study is also the first one on human GIST mouse xenografts established using patient biopsies.

Assessment of the heat shock protein 90 (HSP90) inhibitor IPI504 alone or in combination with the tyrosine kinase inhibitor (TKI) imatinib in mice carrying xenografts of human gastrointestinal stromal tumors (GIST)

10534

Background: Inhibition of HSP90 is a new strategy for treatment of GIST. IPI-504 is a potent i.v. HSP90 inhibitor. We assessed the activity of IPI-504 in imatinib-sensitive GIST xenografts, alone/combined with the TKI. Methods: Human GIST882 cells (KIT exon 13 mut.) were grafted in 43 nude mice, who were randomized to 4 groups: A (n=13; control); B (n=18; IPI-504 100 mg/kg 3x/wk p.o.); C (n=8; imatinib 50 mg/kg 2x/d p.o.); D (n=4; IPI-504+imatinib, dose/schedule as above) for 2 weeks. Histopathological assessment was done by H&E and KIT immunostaining, histological response (HR) was defined by magnitude of necrosis and myxoid degeneration [grade 1 (0–10%), 2 (>10% - ≤ 50%), 3 (> 50% - ≤90%), 4 (>90%)]. Expression/activation of KIT and its signaling (AKT, S6, MAPK) was assessed by Western blot. Results: IPI-504 alone significantly reduced tumor volume (41%) at day 14, further enhanced by adding imatinib (58%). Imatinib alone led to only a 5% reduction. IPI-504 induced grade 2 HR in 17/36 tumors, while the majority of tumors (13/15) treated with imatinib showed grade 1 HR. Grade 3/4 HRs were only seen with the combination. Mitosis decreased 3.3-fold, apoptosis increased 1.3-fold with IPI-504. Despite substantial reduction in mitotic activity in C and D (8.2- and 82-fold), apoptosis was virtually unaffected. In the IPI-504 arm, KIT levels were partially downregulated. Imatinib alone had no effect on KIT expression, while the combination produced a marked suppression of total KIT, accompanied by complete downregulation of the signaling. Loss of KIT in the combination arm was confirmed by immunostaining. Although KIT was not completely degraded with IPI-504, measurable effects on activation of AKT, S6 and MAPK were observed. Conclusions: IPI-504 has consistent antitumor effects in GIST xenografts, both histologically and on the molecular level. Combining IPI-504 with imatinib substantially enhances anti-tumor activity, providing a strong rationale for clinical trials of IPI-504 in GIST as single agent and in combination.

[Table: see text]

[Ocular hypertension--follow up or treatment?]

Ocular hypertension is an increase in the pressure in the eyes that is above the range considered normal with no detectable changes in vision or damage to the structure of your eyes. The term is used to distinguish people with elevated pressure from those with glaucoma, but not all people with ocular hypertension will develop this disease. However, there is an increased risk of glaucoma among those with ocular hypertension, so regular comprehensive eye examinations are essential to the overall eye health.