Drug Testing Research Articles

Simple and Rapid Method of Microwell Array Fabrication for Drug Testing on 3D Cancer Spheroids.

Three-dimensional (3D) cell culture systems are becoming increasingly popular due to their ability to mimic the complex process of angiogenesis in cancer, providing more accurate and physiologically relevant data than traditional two-dimensional (2D) cell culture systems. Microwell systems are particularly useful in this context as they provide a microenvironment that more closely resembles the in vivo environment than traditional microwells. Poly(ethylene glycol) (PEG) microwells are particularly advantageous due to their bio-inertness and the ability to tailor their material characteristics depending on the PEG molecular weight. Although there are several methods available for microwell fabrication, most of them are time-consuming and expensive. The current study utilizes a low-cost laser etching technique on poly(methyl methacrylate) materials followed by molding with PDMS to produce microwells. The optimal conditions for making concave microwells are an engraving parameter speed of 600 mm/s, power of 20%, and a design diameter of the microwell of 0.4 mm. The artificial tumor achieved its full size after 7 days of cell growth in a microwell system, and the cells developed drugs through a live/dead assay test. The results of the drug testing revealed that the IC50 value of zerumbone-loaded liposomes in HepG2 was 4.53 pM, which is greater than the IC50 value of zerumbone. The HepG2 cancer sphere's 3D platform for medication testing revealed that zerumbone-loaded liposomes were very effective at high doses. These findings generally imply that zerumbone-loaded liposomes have the capacity to target the liver and maintain medication delivery.

Abstract LB435: Large panel organoid drug testing combined with biomarker analysis: Unveiling prospects for mechanism of action identification and preclinical patient stratification

Abstract Introduction The development of oncology drugs has a persistently high attrition rate of greater than 95%, requiring the development and implementation of novel models and technologies aimed at better predictive abilities during the preclinical phase. Among these, organoid technologies, which involve propagating tumor stem cells in a near-native state, have proven to markedly advance drug testing with enhanced precision. Our previously developed assay-ready organoid technology has paved the way for large panel organoid screening, allowing organoids to augment the efficiency of drug development pipelines, boost patient-derived model usage in preclinical studies, and facilitate accurate predictions of drug action mechanisms. Here, we present a proof-of-concept (POC) large scale organoid experiment, studying the responses of 50 models to the cytotoxic agent paclitaxel, using next generation sequencing data to analyze the drug mechanism of action (MOA) and identify biomarkers that predict drug responses. Methods A panel of 50 organoid models was characterized for paclitaxel response in 9-dose-response curves by measuring ATP levels after a 5-day exposure. Models were genomically profiled by whole-exome sequencing (n = 47) and whole-transcriptome sequencing (n = 44) to analyze the association between organoid pharmacology data and genomic information and elucidate genes and pathways that may be related with, or predictive of, the treatment responses. We performed biomarker analysis on gene expression, mutation, and copy number alteration levels. Results By assessing organoid sensitivity to paclitaxel, we observed no significant indication-specific difference in organoid responses across 7 cancer types. The 50 models were then categorized into responders (AUC < 1.5; n=15) and non-responders (AUC > 2.6; n=14) for biomarker discovery. Differential expression analysis and pathway activation analysis revealed genes and pathways involved in the cell cycle and DNA replication. DNA recombination differentiates responders from non-responders, while genes involved in epithelial cell proliferation, differentiation, and wound healing are associated with drug resistance. Mutation of proto-oncogene RB Transcriptional Corepressor 1, RB1 (a negative regulator of the cell cycle), was found to be a biomarker enriched in non-responders to paclitaxel, corroborating earlier clinical findings. Using the identified profile, we predicted responses for non-tested models in our biobank and validated our approach. Conclusion Large panel organoid drug screening in combination with biomarker analysis brings great opportunities for increasing drug pipeline efficiency. The POC here presented highlights how such a screen can identify MOAs and identify relevant biomarker profiles to be used in clinical trial patient stratification. Citation Format: Linda Xue, Liza Wijler, Marten Hornsveld, Sheng Guo, Leo Price, Marrit Putker, Ludovic Bourre. Large panel organoid drug testing combined with biomarker analysis: Unveiling prospects for mechanism of action identification and preclinical patient stratification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB435.

Abstract LB437: Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells

Abstract Goals: The primary goal of this study was to develop a 3D functional bioassay to assess the relative invasiveness of bladder cancer cells. This model will support the testing of migrastatic drugs and investigation of the molecular mechanisms which allow for bladder cancer cell invasion to occur. Methods: Our model uses an organ-on-a-chip platform to assess bladder cancer cell invasiveness. This platform supports 3D culture of cells as well as pharmacokinetic studies. Our chips were designed to have a center channel to hold cells supported in Matrigel®, 2 adjacent side channels filled with Matrigel® only, and 2 outer media channels. Total cell and Matrigel® side channel length is 3 cm, channel height is 150 µm, and each channel width is 1 mm. Four bladder cancer cell lines (MB49, T24, J82, RT4) and cells isolated from a mouse bladder were used to develop our model. Cells were mixed with 1:1 media and Matrigel® and a total of 5,000 cells/µl introduced into the center channel. The 2 adjacent side channels were then filled with Matrigel®. The upper media channel was filled with 10% FBS cell culture media while the lower media channel was filled with 1% charcoal stripped cell culture media to thereby create a nutrient and growth factor gradient. Invasion of cells into the Matrigel®-containing side channels was assessed every 24 hours. Using the ImageXpress machine (Molecular Dynamics), we measured the furthest distance travelled by the cells. The chips were then fixed in 4% paraformaldehyde and stained using FITC-phalloidin and DAPI. Results: J82 and T24 cell lines, derived from patients with muscle invasive bladder cancer, and the MB49 cell line, a highly invasive mouse bladder cancer cell line, started invading into the Matrigel® side channels within 24 hours. T24, J82, and MB49 cells moved a maximum of 110, 87, and 170 µm by 48 hours, respectively. In contrast, RT4 cells, derived from a patient with non-invasive bladder cancer, took 48 hours to invade the Matrigel® channels and only invaded a maximum of 3 µm. Cells isolated from a mouse bladder did not invade into the Matrigel® side channels but survived within the chips for over 20 days. Staining of chips with DAPI and FITC-phalloidin allowed for clear visualization of cells and the actin cytoskeleton and demonstrated that immunostaining of cells within chips is possible. Conclusions: Our chip model allows for studying the invasiveness of bladder cancer cells and immunostaining experiments which can be used to assess the molecular mechanisms which drive invasion. It can also support the growth and assessment of primary cells. This model has the potential to improve bladder cancer patient treatments and outcomes by providing a physiologically relevant system to test new and existing drug combinations and to better understand the molecular mechanisms which drive bladder cancer cell invasion. Citation Format: Desiree Ewell, Nita Vue, Sakib Moinuddin, Tanoy Sarkar, Fakhrul Ahsan, Ruth L. Vinall. Development of a bladder cancer-on-a-chip assay to assess the invasive potential of bladder cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB437.

Smartphone swabs as an emerging tool for toxicology testing: a proof-of-concept study in a nightclub.

Smartphones have become everyday objects on which the accumulation of fingerprints is significant. In addition, a large proportion of the population regularly uses a smartphone, especially younger people. The objective of this study was to evaluate smartphones as a new matrix for toxico-epidemiology. This study was conducted during two separate events (techno and trance) at an electronic music nightclub in Grenoble, France. Data on reported drug use and whether drugs were snorted directly from the surface of the smartphone were collected using an anonymous questionnaire completed voluntarily by drug users. Then, a dry swab was rubbed for 20 s on all sides of the smartphone. The extract was analyzed by liquid chromatography coupled to tandem mass spectrometry on a Xevo TQ-XS system (Waters). In total, 122 swabs from 122 drug users were collected. The three main drugs identified were MDMA (n=83), cocaine (n=59), and THC (n=51). Based on declarative data, sensitivity ranged from 73 to 97.2 % and specificity from 71.8 to 88.1 % for MDMA, cocaine, and THC. Other substances were identified such as cocaine adulterants, ketamine, amphetamine, LSD, methamphetamine, CBD, DMT, heroin, mescaline, and several NPS. Numerous medications were also identified, such as antidepressants, anxiolytics, hypnotics, and painkillers. Different use patterns were identified between the two events. This proof-of-concept study on 122 subjects shows that smartphone swab analysis could provide a useful and complementary tool for drug testing, especially for harm-reduction programs and toxico-epidemiolgy studies, with acceptable test performance, despite declarative data.

Abstract LB088: CANCollaborate: Transforming rare cancer research through cooperation and collaboration

Abstract CANCollaborate is a groundbreaking initiative focused on revolutionizing rare cancer research through global cooperation and was founded upon the realization that collective action is crucial for effectively addressing the myriad rare forms of cancer. Rare cancers typically have outdated treatment guidelines, a lack of targeted therapy options due to insufficient research into their biology, and consequently, a failure to keep pace with the advancements in survival outcomes seen in more common cancers over the past few decades. The initiative is rooted in five core premises: the shared goal of all stakeholders to improve rare cancer care, the prevalence of rare cancers constituting a substantial global burden, the scattered nature of rare cancer researchers and resources, existing disincentives hindering collaboration, and the untapped potential of coordinated efforts. CANCollaborate addresses these challenges by fostering open communication, encouraging cooperation, and creating collaborations among researchers, institutions, pharmaceutical and biotech companies, patient advocacy groups, financiers, and regulators. The first focus is on appendiceal cancer (AC). AC is exceedingly rare, affecting 1 to 2 people per million, but incidence has been increasing with one study seeing a 232% increase in the U.S. between 2000 and 2016. For some subtypes of AC, management is extrapolated from colorectal cancer (CRC) guidelines, even though it was established that AC is molecularly distinct from CRC. Coordinated collaboration is essential in advancing the field, given that many physicians involved in treating and researching appendiceal cancer often have it as a secondary focus, rather than being their primary area of concentration. In our brief existence, we've successfully facilitated collaborations for appendiceal organoid generation and testing by connecting a leading organoid scientist with a physician who sees AC patients. Additionally, we have established collaborations with a biotech company with an ex-vivo drug testing platform to surgical oncologists for commencing AC susceptibility testing to potential therapeutics. Key components of CANCollaborate include regular communication, frequent workshops, promoting transparency, and sharing research developments, challenges, and results. By forming collaborations among diverse stakeholders, CANCollaborate seeks to diversify and de-risk rare cancer research by eliminating existing disincentives by rewarding collaborative efforts and fostering new forms of incentives, transforming high-risk, low-return efforts into high-return, low-risk endeavors. CANCollaborate invites all stakeholders in the field of cancer research to join by working together, sharing knowledge, and creating a global network. Together we can accelerate progress, eliminate redundancy, and ultimately contribute to the eradication of cancer. Citation Format: Jamie Barber, Kyra Itskowitz, Jane Wilkinson. CANCollaborate: Transforming rare cancer research through cooperation and collaboration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB088.

Human Dermal Decellularized ECM Hydrogels as Scaffolds for 3D In Vitro Skin Aging Models.

Biomaterials play an important role in the development of advancing three dimensional (3D) in vitro skin models, providing valuable insights for drug testing and tissue-specific modeling. Commercial materials, such as collagen, fibrin or alginate, have been widely used in skin modeling. However, they do not adequately represent the molecular complexity of skin components. On this regard, the development of novel biomaterials that represent the complexity of tissues is becoming more important in the design of advanced models. In this study, we have obtained aged human decellularized dermal extracellular matrix (dECM) hydrogels extracted from cadaveric human skin and demonstrated their potential as scaffold for advanced skin models. These dECM hydrogels effectively reproduce the complex fibrillar structure of other common scaffolds, exhibiting similar mechanical properties, while preserving the molecular composition of the native dermis. It is worth noting that fibroblasts embedded within human dECM hydrogels exhibit a behavior more representative of natural skin compared to commercial collagen hydrogels, where uncontrolled cell proliferation leads to material shrinkage. The described human dECM hydrogel is able to be used as scaffold for dermal fibroblasts in a skin aging-on-a-chip model. These results demonstrate that dECM hydrogels preserve essential components of the native human dermis making them a suitable option for the development of 3D skin aging models that accurately represent the cellular microenvironment, improving existing in vitro skin models and allowing for more reliable results in dermatopathological studies.

Drug Screenings in Practice

This research article will contextualize drug testing and conditions of supervision by analyzing eight original in-depth interview and survey narratives provided by persons are in treatment for substance use disorder. We identify a gap in the literature surrounding drug testing as part of community supervision. Specifically, the practice of drug testing from the perspective of the person ordered to test is not well documented. We consider how these experiences diverge from the intention of drug testing by supervising agencies as described in the prior scholarship. This cleavage between the expectations, experiences, and understanding of persons being tested relative to those of supervision agencies presents an avenue for the government to improve community relations, and specifically, improve trust among formerly incarcerated persons towards the supervision process, thereby increasing its legitimacy while enacting procedural justice. The persons under supervision describe broad criminal justice experiences and histories with illicit substances that resulted in drug screenings. The opinions from persons who use drugs towards drug testing and related conditions also vary and suggest evidence-based practices involving drug screening could be helpful to improve compliance with conditions and increase trust towards supervision agencies and courts. Opinions towards obligatory drug screens ranged from fear to one of gratitude. A common theme emerged: when drug tests were viewed as avoidable, respondents described changing their behavior to avoid testing—such as avoiding employers who may test for drug use; when screenings were understood as obligatory, like in the context of court ordered community-based addiction treatment, some respondents identified the broader context of the testing as helpful to their abstinence from drug use. Respondents described drug screenings as impacting their employment, economic well-being, and freedom—in particular, failed drug screens on community supervision, including drug court and other specialized supervision caseloads, could result in punitive action including incarceration and other adverse outcomes like job loss. The risk acknowledgement, however, of consequences of a failed drug screen, had not up to the point of our interview, resulted in long-term abstinence from substances for any of the respondents under community-based supervision.

General Practice or Evidence-Based? Exploring Drug Testing for People without a Substance Use Disorder

The criminal justice system is enthralled with drug testing. It is a billion dollar industry fueled by drug courts, swift certain, and fair strategies, and the idea that probation is a privilege. It has become so pervasive that even people without an identified drug problem are often tested on a regular basis. While the field has accepted drug testing as a key component, this paper suggests that the data, while limited, is not as pervasive as the practice itself. This paper will explore the current research on drug testing, how effective it is for people without an identified substance use issue, and what are some of the collateral consequences to testing that may offset any perceived or real benefit to the practice.

The Cost of Testing

An edited and condensed version of remarks delivered by LaTonya Myers as a panelist at the “Drug Testing and Community Supervision: Interrogating Policy, Practice, and Purpose” convening in Columbus, Ohio, in November 2023. Myers discusses her experiences—mostly negative—of probation and drug testing in Philadelphia, which began at age 12 after she intervened in a domestic violence incident involving her mother, and outlines a very different model of supervision. Myers is the founder of Above All Odds, an organization dedicated to supporting those harmed by mass supervision and incarceration in Philadelphia and to advocating for systemic change.

The Cost of Testing

My name is Randall McNeil. I currently work as a Policy Analyst at Arnold Ventures, and I was formerly incarcerated. Released in August 2022 under DC’s IRAA reform after spending 24 years and 4 months in prison, I expected support from my probation officer upon my return to society. However, I encountered unexpected challenges. Initially assigned a probation officer who was temporary, I was subjected to monthly drug testing. Before my first drug test, I was informed of yet another change in probation officers. This cycle continued until I finally received a permanent probation officer, who immediately increased the frequency of drug testing as a means for me to earn trust. Additionally, she insisted on office and home visits instead of accommodating my job schedule, providing no transitional support. Currently residing in Maryland with my wife, I recently faced an alarming situation when I received notice from my probation officer that the judge that released me contacted the Metropolitan Police Department (MPD) and reported me as non-compliant due to a change of address within Maryland, which I failed to notify. As a former DC prisoner with a prior gun charge, I am obligated to register as a gun offender with the MPD. Despite adhering to all other release requirements, my failure to update my address led to a judge authorizing an arrest warrant. Fortunately, the officer granted me an opportunity to rectify the oversight, which I promptly addressed. This experience highlighted the precariousness of one’s circumstances, where even a minor lapse in compliance could have severe consequences. I am relieved to report that I am now fully compliant with all regulations.

Comparing drug testing methods in the trucking industry: The drug and alcohol clearinghouse versus hair testing

AbstractThe Omnibus Transportation Employee Testing Act of 1991 mandated urine drug testing for U.S. truck drivers but some trucking companies prefer hair testing because it has a longer look back period and better detects lifestyle drug users. Previous research established that 276,500 current truck drivers may be disqualified if they submitted to hair drug tests instead of federally accepted urinalysis. This research compares hair and urine drug test results provided by eight U.S. trucking companies who are members of the alliance for driver safety and security (i.e., the trucking alliance) with urine test results drawn from the federal drug and alcohol clearinghouse to determine the differences in hair versus urine positivity rates and drugs detected. Results indicate that hair testing has a 6.00% positivity rate, 4.01% higher than urine. If this difference were generalized to the drivers who submitted urine tests to the drug and alcohol clearinghouse, hair testing would have likely disqualified 57,337 additional drivers in 2020. Results further indicate urine testing is better able to detect marijuana while hair testing is superior in detecting cocaine and opioids. This implies federal agencies should consider allowing hair test results to be submitted to the drug and alcohol clearinghouse to support a more drug‐free driver workforce.

The Utility of Drug Testing for Probation Risk Classification

Drug testing—either random, scheduled, or for-cause—is a common condition of community supervision. This study investigates the utility of drug testing measures in predicting arrest or revocation outcomes for individuals on probation. Results were generated during the development of a set of new risk classification algorithms for individuals on probation or parole in Georgia. Multiple analytic approaches and predictive factors were tested in the development of these models that were built using data for approximately 154,000 individuals who began probation or parole between January 1, 2016, and December 31, 2019. Accuracy at predicting rearrest was improved by implementing time-period-specific models; using recent rather than lifetime criminal history; and incorporating dynamic measures of both protective and risk factors, including drug test results and absence of testing. Models were estimated separately for men and women, for different supervision statuses (probation-only, split-sentence probation, and parole), and for three consecutive time periods (first quarter, next three quarters, one-plus years). Positive test results were predictive of future arrest or revocation, while negative results and absence of testing in latter-period models were associated with reduced risk. Results are presented for the probation-only models for men and women, but similar results obtained for the split-probation and parole models.

Drug War Dragnet

This paper examines the multilayered dynamics behind the drivers of overdose deaths, criminal legal-system involvement, and the drug war infiltration of people’s everyday lives—especially for people under community supervision. While incarceration receives more media and academic attention because of its particular cruelty, almost twice as many people—3.7 million, or one in every sixty-nine U.S. adults—are under community supervision. Probation and parole are commonly understood as “alternatives to incarceration” or “lenient sentences,” but people on supervision must endure constant monitoring, perpetually under the threat of incarceration. Drug war policies and practices have profoundly shaped probation and parole. Regardless of someone’s original sentence, abstinence from drugs, drug testing, submission to warrantless searches, and court-ordered treatment are routine features of supervision. The putative goal of community supervision is to ensure successful reintegration; yet drug war surveillance enacts extensive barriers, while not reducing drug use or drug-related harms like overdose. In order to ensure health, financial security, and overall well-being of those under supervision, policymakers, probation and parole officers, clinicians, service providers, and researchers must work to identify and remove barriers to care, including routine drug testing, substandard or forced substance use disorder treatment, and poor-quality services and support.

Missing the Mark

For several years, Arnold Ventures has been investing in supervision reform, supporting researchers, practitioners, advocates, and scholars who are seeking to achieve a fundamental shift in policy, practice, and outcomes. We envision systems that are grounded not in catching failure, but in facilitating and supporting success. Understanding and challenging current norms on condition setting and enforcement is a key piece of that, and drug testing conditions in particular warrant significant scrutiny and assessment. Ubiquitously imposed, potentially enormously harmful, and minimally supported by research and evidence, we are proud to support field leaders who are reexamining punitive drug testing and developing innovative solutions to help support all people on supervision, particularly people with substance use histories.

Practitioners for Change

Julie Rud is the community corrections field services area director for Hennepin County (Minneapolis). Only five states have more people on probation than Minnesota, yet Hennepin County is a leader in reforms to supervision, including eliminating fees and cutting the use of drug testing in half since 2017. Below is an edited and condensed version of remarks delivered by Rud as a panelist at the “Drug Testing and Community Supervision: Interrogating Policy, Practice, and Purpose” convening in Columbus, Ohio, in November 2023.

What Is Probation, Anyway? Reflections from a Decade of Research

Observers of the criminal legal system in the U.S. have increasingly looked beyond prisons to map the expansion and consequences of mass supervision, or the role of probation and parole in people’s lived experiences of correctional control. In this commentary, I reflect on the lessons learned from a decade of research on mass probation, focusing in particular on how drug testing helps us understand the risks and potential benefits of supervision. In light of the concerns about the harms of supervision, I argue that scholars and advocates should reconsider the fundamental purpose of probation and ask what it might look like to abolish supervision as we know it.

Appearance of hexahydrocannabinols as recreational drugs and implications for cannabis drug testing – focus on HHC, HHC-P, HHC-O and HHC-H

This study investigated the effects of hexahydrocannabinol (HHC) and other unclassified cannabinoids, which were recently introduced to the recreational drug market, on cannabis drug testing in urine and oral fluid samples. After the appearance of HHC in Sweden in 2022, the number of posts about HHC on an online drug discussion forum increased significantly in the spring of 2023, indicating increased interest and use. In parallel, the frequency of false positive screening tests for tetrahydrocannabinol (THC) in oral fluid, and for its carboxy metabolite (THC-COOH) in urine, rose from <2% to >10%. This suggested that HHC cross-reacted with the antibodies in the immunoassay screening, which was confirmed in spiking experiments with HHC, HHC-COOH, HHC acetate (HHC-O), hexahydrocannabihexol (HHC-H), hexahydrocannabiphorol (HHC-P), and THC-P. When HHC and HHC-P were classified as narcotics in Sweden on 11 July 2023, they disappeared from the online and street shops market and were replaced by other unregulated variants (e.g. HHC-O and THC-P). In urine samples submitted for routine cannabis drug testing, HHC-COOH concentrations up to 205 (mean 60, median 27) µg/L were observed. To conclude, cannabis drug testing cannot rely on results from immunoassay screening, as it cannot distinguish between different tetra- and hexahydrocannabinols, some being classified but others unregulated. The current trend for increased use of unregulated cannabinols will likely increase the proportion of positive cannabis screening results that need to be confirmed with mass spectrometric methods. However, the observed cross-reactivity also means a way to pick up use of new cannabinoids that otherwise risk going undetected.

Clinician Ordering and Management Patterns of Urine Toxicology Results at a Cancer Center

ContextOpioid therapy is a cornerstone for treatment of cancer-related pain, but standardized management practices for patients with cancer and aberrant urine drug test (UDT) results are lacking. ObjectivesTo identify the prevalence of UDT ordering (both screening and definitive testing) in the oncology setting and to examine clinician management practices for patients with cancer on opioid therapy with aberrant definitive UDT results. MethodsWe conducted a retrospective chart review of patients with cancer on opioid therapy at an academic cancer center in the United States. Outcomes included UDT ordering patterns and clinician management practices in response to aberrant definitive UDT results. ResultsOur study revealed an overall UDT ordering rate of 3.7% among 10,371 patients with cancer on opioid therapy. Among 143 patients for whom definitive UDTs were ordered, oncologists only ordered 14 (9.8%) UDTs, while palliative care ordered the majority (n = 129; 90.2%). Fifty-five (38.5%) patients had aberrant results, and the most common aberrancy was presence of illicit drugs 22 [15.4%]. Clinicians rarely made medication changes (20 [36.4%]) when UDT results were aberrant, and in the setting of possible fentanyl use (n = 8), only 3 (37.5%) patients were started/switched to methadone, and none were started/switched to buprenorphine. ConclusionOverall UDT ordering was infrequent for patients with cancer on opioid therapy, especially by oncologists, and clinicians rarely made prescribing changes when definitive UDT results were aberrant. More definitive guidance related to UDT ordering and opioid management are needed for patients with cancer and aberrant UDT results.

Workplace Drug Testing As A Drug Prevention Strategy for Public Transport Drivers: A Cross-sectional Study

Workplace Drug Testing As A Drug Prevention Strategy for Public Transport Drivers: A Cross-sectional Study

Influence of the internal structure of straight microchannels on inertial transport behavior of particles

The rapid advancement of Micro-Electro-Mechanical Systems (MEMS) technology has established microfluidics as a pivotal field. This technology marks the onset of a new era in various applications, including drug testing, cell culture, and disease monitoring, underscoring its extensive practicality and potential for future exploration. This research delves into the intricate behavior of particle inertial migration within microchannels, particularly focusing on the impact of different channel structures and Reynolds numbers (Re). Our studies reveal that particles in microchannels with one-sided sharp-cornered microstructures migrate towards the sharp corner at a relative position of 0.4 under low flow rates, and towards the straight wall side at a relative position of 0.8 under high flow rates. The migration pattern of equilibrium positions varies with different arrangements of sharp-corner structures, achieving stability at the channel's center only when the sharp corners are symmetrically arranged on both sides. Our investigation into the shape of microstructures indicates that sharp-cornered structures generate a more stable secondary flow compared to rectangular and semi-circular structures, preventing particle aggregation at the outlet. To address the challenges associated with handling variable cross-section geometries and solid-wall boundaries in dissipative particle dynamics methods effectively, we have developed a dissipative particle dynamics model specifically for analyzing such microchannels. Building upon our previous research, this model introduces a conservative force coefficient for particles within the microstructured region and an interaction zone that only involves repulsive forces, aligning well with experimental outcomes. Through the study of microstructures' geometric shapes, this paper offers guidance for designing microchannels for particle enrichment. Furthermore, the dissipative particle dynamics model established for the particle flow and solid structure interaction within microstructured channels provides insights into the mesoscale dynamics of liquid-solid two-phase flow and particle motion. In conclusion, this paper aims to enhance particle motion sample preparation techniques, thereby broadening the scope of microfluidic applications in the biomedical field.