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Dive into the research topics where Dayong Lee is active.

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Featured researches published by Dayong Lee.


Clinical Chemistry | 2011

Oral Fluid Cannabinoids in Chronic, Daily Cannabis Smokers during Sustained, Monitored Abstinence

Dayong Lee; Garry Milman; Allan J. Barnes; Robert S. Goodwin; Jussi Hirvonen; Marilyn A. Huestis

BACKGROUND Oral fluid (OF) is an accepted alternative biological matrix for drug treatment, workplace, and DUID (driving under the influence of drugs) investigations, but establishing the cannabinoid OF detection window and concentration cutoff criteria are important. METHODS Cannabinoid concentrations were quantified in OF from chronic, daily cannabis smokers during monitored abstinence. Δ(9)-tetrahydrocannabinol (THC)(3), cannabidiol (CBD), cannabinol (CBN), and 11-nor-9-carboxy-THC (THCCOOH) were determined in daily OF samples collected with the Quantisal™ device. GC-MS limits of quantification (LOQ) were 0.5 μg/L for THC and CBD, 1 μg/L for CBN, and 7.5 ng/L for THCCOOH. RESULTS After providing written informed consent for this institutional review board-approved study, 28 participants resided from 4 to 33 days on the secure research unit and provided 577 OF specimens. At the LOQ, THC was generally quantifiable for 48 h, whereas CBD and CBN were detected only at admission. Median THCCOOH detection time was 13 days (CI 6.4-19.6 days). Mean THC detection rates decreased from 89.3% at admission to 17.9% after 48 h, whereas THCCOOH gradually decreased from 89.3% to 64.3% within 4 days. Criteria of THC ≥2 μg/L and THCCOOH ≥20 ng/L reduced detection to <48 h in chronic cannabis smokers. An OF THCCOOH/THC ratio ≤4 ng/μg or presence of CBD or CBN may indicate more recent smoking. CONCLUSIONS THC, THCCOOH, CBD, and CBN quantification in confirmatory OF cannabinoid testing is recommended. Inclusion of multiple cannabinoid cutoffs accounted for residual cannabinoid excretion in OF from chronic, daily cannabis smokers and could reduce the potential for positive test results from passive cannabis smoke exposure and lead to greatly improved test interpretation.


Drug and Alcohol Dependence | 2013

The dose effects of short-term dronabinol (oral THC) maintenance in daily cannabis users.

Ryan Vandrey; Maxine L. Stitzer; Miriam Z. Mintzer; Marilyn A. Huestis; Jeannie A. Murray; Dayong Lee

BACKGROUND Prior studies have separately examined the effects of dronabinol (oral THC) on cannabis withdrawal, cognitive performance, and the acute effects of smoked cannabis. A single study examining these clinically relevant domains would benefit the continued evaluation of dronabinol as a potential medication for the treatment of cannabis use disorders. METHODS Thirteen daily cannabis smokers completed a within-subject crossover study and received 0, 30, 60 and 120mg dronabinol per day for 5 consecutive days. Vital signs and subjective ratings of cannabis withdrawal, craving and sleep were obtained daily; outcomes under active dose conditions were compared to those obtained under placebo dosing. On the 5th day of medication maintenance, participants completed a comprehensive cognitive performance battery and then smoked five puffs of cannabis for subjective effects evaluation. Each dronabinol maintenance period occurred in a counterbalanced order and was separated by 9 days of ad libitum cannabis use. RESULTS Dronabinol dose-dependently attenuated cannabis withdrawal and resulted in few adverse side effects or decrements in cognitive performance. Surprisingly, dronabinol did not alter the subjective effects of smoked cannabis, but cannabis-induced increases in heart rate were attenuated by the 60 and 120mg doses. CONCLUSIONS Dronabinols ability to dose-dependently suppress cannabis withdrawal may be therapeutically beneficial to individuals trying to stop cannabis use. The absence of gross cognitive impairment or side effects in this study supports safety of doses up to 120mg/day. Continued evaluation of dronabinol in targeted clinical studies of cannabis treatment, using an expanded range of doses, is warranted.


Clinical Chemistry | 2012

Cannabinoid Disposition in Oral Fluid after Controlled Smoked Cannabis

Dayong Lee; David M. Schwope; Garry Milman; Allan J. Barnes; David A. Gorelick; Marilyn A. Huestis

BACKGROUND We measured Δ(9)-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) disposition in oral fluid (OF) following controlled cannabis smoking to evaluate whether monitoring multiple cannabinoids in OF improved OF test interpretation. METHODS Cannabis smokers provided written informed consent for this institutional review board-approved study. OF was collected with the Quantisal™ device following ad libitum smoking of one 6.8% THC cigarette. Cannabinoids were quantified by 2-dimensional GC-MS. We evaluated 8 alternative cutoffs based on different drug testing program needs. RESULTS 10 participants provided 86 OF samples -0.5 h before and 0.25, 0.5, 1, 2, 3, 4, 6, and 22 h after initiation of smoking. Before smoking, OF samples of 4 and 9 participants were positive for THC and THCCOOH, respectively, but none were positive for CBD and CBN. Maximum THC, CBD, and CBN concentrations occurred within 0.5 h, with medians of 644, 30.4, and 49.0 μg/L, respectively. All samples were THC positive at 6 h (2.1-44.4 μg/L), and 4 of 6 were positive at 22 h. CBD and CBN were positive only up to 6 h in 3 (0.6-2.1 μg/L) and 4 (1.0-4.4 μg/L) participants, respectively. The median maximum THCCOOH OF concentration was 115 ng/L, with all samples positive to 6 h (14.8-263 ng/L) and 5 of 6 positive at 22 h. CONCLUSIONS By quantifying multiple cannabinoids and evaluating different analytical cutoffs after controlled cannabis smoking, we determined windows of drug detection, found suggested markers of recent smoking, and minimized the potential for passive contamination.


Clinical Chemistry | 2012

Cannabinoid Stability in Authentic Oral Fluid after Controlled Cannabis Smoking

Dayong Lee; Garry Milman; David M. Schwope; Allan J. Barnes; David A. Gorelick; Marilyn A. Huestis

BACKGROUND Defining cannabinoid stability in authentic oral fluid (OF) is critically important for result interpretation. There are few published OF stability data, and of those available, all employed fortified synthetic OF solutions or elution buffers; none included authentic OF following controlled cannabis smoking. METHODS An expectorated OF pool and a pool of OF collected with Quantisal™ devices were prepared for each of 10 participants. Δ⁹-tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), and cannabinol (CBN) stability in each of 10 authentic expectorated and Quantisal-collected OF pools were determined after storage at 4 °C for 1 and 4 weeks and at -20 °C for 4 and 24 weeks. Results within ±20% of baseline concentrations analyzed within 24 h of collection were considered stable. RESULTS All Quantisal OF cannabinoid concentrations were stable for 1 week at 4 °C. After 4 weeks at 4 °C, as well as 4 and 24 weeks at -20 °C, THC was stable in 90%, 80%, and 80% and THCCOOH in 89%, 40%, and 50% of Quantisal samples, respectively. Cannabinoids in expectorated OF were less stable than in Quantisal samples when refrigerated or frozen. After 4 weeks at 4 and -20 °C, CBD and CBN were stable in 33%-100% of Quantisal and expectorated samples; by 24 weeks at -20 °C, CBD and CBN were stable in ≤ 44%. CONCLUSIONS Cannabinoid OF stability varied by analyte, collection method, and storage duration and temperature, and across participants. OF collection with a device containing an elution/stabilization buffer, sample storage at 4 °C, and analysis within 4 weeks is preferred to maximize result accuracy.


Drug Testing and Analysis | 2014

Current knowledge on cannabinoids in oral fluid

Dayong Lee; Marilyn A. Huestis

Oral fluid (OF) is a new biological matrix for clinical and forensic drug testing, offering non-invasive and directly observable sample collection reducing adulteration potential, ease of multiple sample collections, lower biohazard risk during collection, recent exposure identification, and stronger correlation with blood than urine concentrations. Because cannabinoids are usually the most prevalent analytes in illicit drug testing, application of OF drug testing requires sufficient scientific data to support sensitive and specific OF cannabinoid detection. This review presents current knowledge of OF cannabinoids, evaluating pharmacokinetic properties, detection windows, and correlation with other biological matrices and impairment from field applications and controlled drug administration studies. In addition, onsite screening technologies, confirmatory analytical methods, drug stability, and effects of sample collection procedure, adulterants, and passive environmental exposure are reviewed. Delta-9-tetrahydrocannabinol OF concentrations could be >1000 µg/L shortly after smoking, whereas minor cannabinoids are detected at 10-fold and metabolites at 1000-fold lower concentrations. OF research over the past decade demonstrated that appropriate interpretation of test results requires a comprehensive understanding of distinct elimination profiles and detection windows for different cannabinoids, which are influenced by administration route, dose, and drug use history. Thus, each drug testing program should establish cut-off criteria, collection/analysis procedures, and storage conditions tailored to its purposes. Building a scientific basis for OF testing is ongoing, with continuing OF cannabinoids research on passive environmental exposure, drug use history, donor physiological conditions, and oral cavity metabolism needed to better understand mechanisms of cannabinoid OF disposition and expand OF drug testing applicability. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.


PLOS ONE | 2013

Psychomotor Function in Chronic Daily Cannabis Smokers during Sustained Abstinence

Wendy M. Bosker; Erin L. Karschner; Dayong Lee; Robert S. Goodwin; Jussi Hirvonen; Robert B. Innis; Eef L. Theunissen; Kim P. C. Kuypers; Marilyn A. Huestis; Johannes G. Ramaekers

Background The present study assessed psychomotor function in chronic, daily cannabis smokers during 3 weeks continuously monitored abstinence on a secure research unit. We hypothesized that psychomotor performance would improve during abstinence of chronic, daily cannabis smokers. Methodology/Principal Findings Performance on the critical tracking (CTT) and divided attention (DAT) tasks was assessed in 19 male chronic, daily cannabis smokers at baseline and after 8, 14–16 and 21–23 days of continuously monitored abstinence. Psychomotor performance was compared to a control group of non-intoxicated occasional drug users. Critical frequency (λc) of the CTT and tracking error and control losses of the DAT were the primary outcome measures. Results showed that chronic cannabis smokers’ performance on the CTT (p<0.001) and the DAT (p<0.001) was impaired during baseline relative to the comparison group. Psychomotor performance in the chronic cannabis smokers improved over 3 weeks of abstinence, but did not recover to equivalent control group performance. Conclusions/Significance Sustained cannabis abstinence moderately improved critical tracking and divided attention performance in chronic, daily cannabis smokers, but impairment was still observable compared to controls after 3 weeks of abstinence. Between group differences, however, need to be interpreted with caution as chronic smokers and controls were not matched for education, social economic status, life style and race.


Journal of Chromatography A | 2013

Simultaneous quantification of Δ9-tetrahydrocannabinol, 11-nor-9-carboxy-tetrahydrocannabinol, cannabidiol and cannabinol in oral fluid by microflow-liquid chromatography–high resolution mass spectrometry

Marta Concheiro; Dayong Lee; Elena Lendoiro; Marilyn A. Huestis

Δ(9)-Tetrahydrocannabinol (THC) is the primary target in oral fluid (OF) for detecting cannabis intake. However, additional biomarkers are needed to solve interpretation issues, such as the possibility of passive inhalation by identifying 11-nor-9-carboxy-THC (THCCOOH), and determining recent cannabis smoking by identifying cannabidiol (CBD) and/or cannabinol (CBN). We developed and comprehensively validated a microflow liquid chromatography (LC)-high resolution mass spectrometry method for simultaneous quantification of THC, THCCOOH, CBD and CBN in OF collected with the Oral-Eze(®) and Quantisal™ devices. One milliliter OF-buffer solution (0.25mL OF and 0.5mL of Oral-Eze buffer, 1:3 dilution, or 0.75mL Quantisal buffer, 1:4 dilution) had proteins precipitated, and the supernatant subjected to CEREX™ Polycrom™ THC solid-phase extraction (SPE). Microflow LC reverse-phase separation was achieved with a gradient mobile phase of 10mM ammonium acetate pH 6 and acetonitrile over 10min. We employed a Q Exactive high resolution mass spectrometer, with compounds identified and quantified by targeted-MSMS experiments. The assay was linear 0.5-50ng/mL for THC, CBD and CBN, and 15-500pg/mL for THCCOOH. Intra- and inter-day and total imprecision were <10.8%CV and bias 86.5-104.9%. Extraction efficiency was 52.4-109.2%, process efficiency 12.2-88.9% and matrix effect ranged from -86 to -6.9%. All analytes were stable for 24h at 5°C on the autosampler. The method was applied to authentic OF specimens collected with Quantisal and Oral-Eze devices. This method provides a rapid simultaneous quantification of THCCOOH and THC, CBD, CBN, with good selectivity and sensitivity, providing the opportunity to improve interpretation of cannabinoid OF results by eliminating the possibility of passive inhalation and providing markers of recent cannabis smoking.


American Journal on Addictions | 2014

Cannabis Withdrawal in Chronic, Frequent Cannabis Smokers during Sustained Abstinence within a Closed Residential Environment

Dayong Lee; Jennifer R. Schroeder; Erin L. Karschner; Robert S. Goodwin; Jussi Hirvonen; David A. Gorelick; Marilyn A. Huestis

OBJECTIVES Chronic, frequent cannabis smokers may experience residual and offset effects, withdrawal, and craving when abstaining from the drug. We characterized the prevalence, duration, and intensity of these effects in chronic frequent cannabis smokers during abstinence on a closed research unit. METHODS Non-treatment-seeking participants (N = 29 on admission, 66% and 34% remaining after 2 and 4 weeks) provided subjective effects data. A battery of five instruments was computer-administered daily to measure psychological, sensory, and physical symptoms associated with cannabinoid intoxication and withdrawal. Plasma and oral fluid specimens were concurrently collected and analyzed for cannabinoids. Outcome variables were evaluated as change from admission (Day 0) with regression models. RESULTS Most abstinence effects, including irritability and anxiety were greatest on Days 0-3 and decreased thereafter. Cannabis craving significantly decreased over time, whereas decreased appetite began to normalize on Day 4. Strange dreams and difficulty getting to sleep increased over time, suggesting intrinsic sleep problems in chronic cannabis smokers. Symptoms likely induced by residual drug effects were at maximum intensity on admission and positively correlated with plasma and oral fluid cannabinoid concentrations on admission but not afterward; these symptoms showed overall prevalence higher than cannabis withdrawal symptoms. CONCLUSIONS The combined influence of residual/offset drug effects, withdrawal, and craving was observed in chronic cannabis smokers during monitored abstinence. Abstinence symptoms were generally more intense in the initial phase, implying importance of early intervention in cannabis quit attempts. Sleep disturbance persisting for an extended period suggests that hypnotic medications could be beneficial in treating cannabis dependence.


Clinical Chemistry | 2013

Oral Fluid Cannabinoids in Chronic Cannabis Smokers during Oral Δ9-Tetrahydrocannabinol Therapy and Smoked Cannabis Challenge

Dayong Lee; Ryan Vandrey; Damodara R. Mendu; Sebastien Anizan; Garry Milman; Jeannie A. Murray; Allan J. Barnes; Marilyn A. Huestis

BACKGROUND Oral Δ(9)-tetrahydrocannabinol (THC) is effective for attenuating cannabis withdrawal and may benefit treatment of cannabis use disorders. Oral fluid (OF) cannabinoid testing, increasing in forensic and workplace settings, could be valuable for monitoring during cannabis treatment. METHODS Eleven cannabis smokers resided on a closed research unit for 51 days and received daily 0, 30, 60, and 120 mg of oral THC in divided doses for 5 days. There was a 5-puff smoked cannabis challenge on the fifth day. Each medication session was separated by 9 days of ad libitum cannabis smoking. OF was collected the evening before and throughout oral THC sessions and analyzed by 2-dimensional GC-MS for THC, cannabidiol (CBD), cannabinol (CBN), 11-hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH). RESULTS During all oral THC administrations, THC OF concentrations decreased to ≤ 78.2, 33.2, and 1.4 μg/L by 24, 48, and 72 h, respectively. CBN also decreased over time, with concentrations 10-fold lower than THC, with none detected beyond 69 h. CBD and 11-OH-THC were rarely detected, only within 19 and 1.6 h after smoking, respectively. THCCOOH OF concentrations were dose dependent and increased over time during 120-mg THC dosing. After cannabis smoking, THC, CBN, and THCCOOH concentrations showed a significant dose effect and decreased significantly over time. CONCLUSIONS Oral THC dosing significantly affected OF THCCOOH but minimally contributed to THC OF concentrations; prior ad libitum smoking was the primary source of THC, CBD, and CBN. Higher cannabinoid concentrations following active oral THC administrations vs placebo suggest a compensatory effect of THC tolerance on smoking topography.


Drug Testing and Analysis | 2015

Oral fluid cannabinoids in chronic frequent cannabis smokers during ad libitum cannabis smoking

Dayong Lee; Ryan Vandrey; Damodara R. Mendu; Jeannie A. Murray; Allan J. Barnes; Marilyn A. Huestis

Oral fluid (OF) offers a simple, non-invasive, directly observable sample collection for clinical and forensic drug testing. Given that chronic cannabis smokers often engage in drug administration multiple times daily, evaluating OF cannabinoid pharmacokinetics during ad libitum smoking is important for practical development of analytical methods and informed interpretation of test results. Eleven cannabis smokers resided in a closed research unit for 51 days, and underwent four, 5-day oral delta-9-tetrahydrocannabinol (THC) treatments. Each medication period was separated by 9 days of ad libitum cannabis smoking from 12:00 to 23:00 h daily. Ten OF samples were collected from 9:00-22:00 h on each of the last ad libitum smoking days (Study Days 4, 18, 32, and 46). As the number of cannabis cigarettes smoked increased over the study days, OF THC, cannabinol (CBN), and 11-nor-9-carboxy-THC (THCCOOH) also increased with a significant effect of time since last smoking (Δtime; range, 0.0-17.4 h) and ≥88% detection rates; concentrations on Day 4 were significantly lower than those on Days 32 and 46 but not Day 18. Within 30 min of smoking, median THC, CBN, and THCCOOH concentrations were 689 µg/L, 116 µg/L, and 147 ng/L, respectively, decreasing to 19.4 µg/L, 2.4 µg/L, and 87.6 ng/L after 10 h. Cannabidiol and 11-hydroxy-THC showed overall lower detection rates of 29 and 8.6%, respectively. Cannabinoid disposition in OF was highly influenced by Δtime and composition of smoked cannabis. Furthermore, cannabinoid OF concentrations increased over ad libitum smoking days, in parallel with increased cannabis self-administration, possibly reflecting development of increased cannabis tolerance.

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Marilyn A. Huestis

National Institute on Drug Abuse

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Allan J. Barnes

National Institute on Drug Abuse

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Garry Milman

National Institute on Drug Abuse

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Robert S. Goodwin

National Institute on Drug Abuse

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Ryan Vandrey

Johns Hopkins University School of Medicine

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Damodara R. Mendu

National Institute on Drug Abuse

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David M. Schwope

National Institute on Drug Abuse

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Erin L. Karschner

National Institute on Drug Abuse

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