Multi-Class Analysis of 57 Drugs Quantitatively in Blood and Qualitatively in Urine by LC-MS/MS to Complement Comprehensive DFC, DUID and Postmortem Testing.

A streamlined LC-MS/MS method utilizing protein precipitation and filtration extraction was developed to consolidate analyses for drug-facilitated crime (DFC), postmortem investigations, and driving under the influence of drugs (DUID) testing. Fifty-seven target drug and metabolite analytes eluted in under 6-minutes and compromised of GHB precursors (1), hallucinogens (3), muscle relaxants (3), anticonvulsants (7), antidepressants (20), antihistamines (5), antipsychotics (11), antihypertensives and alpha-adrenergics (3), analgesics and anesthetics (3), and miscellaneous (1) in blood (quantitatively) and urine (qualitatively). Limits of detection were set to meet the more challenging sensitivity requirements for DFC, and are therefore also suitable for postmortem investigations, and other forensic casework, including DUID. Comprehensive ASB/ANSI validation was performed, and applicability studies examined 72 proficiency test blood and urine samples, along with 9,206 unique blood and urines samples from 5,192 authentic forensic cases that resulted in 11,961 positive analytes in samples. By expanding the analytical reach across multiple drug classes through a unified approach and screening a wider number of drugs, the technique can identify substances that might have previously evaded detection, thereby enhancing laboratory efficiency by minimizing the need for multiple tests. When combined with a recently developed in-house method, this integrated testing strategy meets the testing requirements outlined in ASB/ANSI standards and recommendations for DFC, postmortem, and Tier 1 DUID analyses.

Exercise and Heat Stress in Well-Healed Burn Survivors: Effects of Cooling Modalities on Thermal and Perceptual Responses.

PURPOSE: Burn injuries that require grafting impair thermoregulation, which may dissuade individuals with such injuries from being physically active. We tested the hypothesis that cooling modalities attenuate core temperature elevations and perceptions of heat stress during physical activity in the heat among adults with well-healed burn injuries. METHODS: Adults with no burn injuries (non-burned), 20-40% body surface area burn injuries (moderate burn), and > 40% body surface area burn injuries (large burn) performed 1 hour of moderate intensity exercise (2.5 ± 0.2 mph and 2% grade) on four different occasions in two environmental conditions (30 °C & 39 °C, 40% relative humidity). Within each environmental condition, we applied one of the following cooling modalities, random assigned, for each visit: no cooling (control), fan at 4 m/s (fan), water spray every 5 min (water spray; scaled to burn area size), or a combination of water spray + fan. RESULTS: In 30 °C, perceptual strain index (PeSI) was reduced in the non-burned and moderate burn groups with water spray + fan, whereas PeSI was reduced with all cooling modalities in the large burn group. The cooling modalities did not affect core temperature responses. In the 39 °C environment, water spray and water spray + fan attenuated the elevation in core temperature (p ≤ 0.007) only in the large burn group. In the moderate burn group, PeSI was decreased with water spray + fan (p = 0.017). In the large burn group, both water spray alone and water spray + fan (p ≤ 0.041) lowered PeSI. CONCLUSIONS: For both environments across burn groups, the applied cooling modalities were generally more effective at reducing indices of perceptual strain relative to indices of thermal strain (e.g., core temperature).

Assessment of postmortem urine fentanyl detection by autopsy dipstick testing in accidental overdose deaths.

Accidental overdose cases continue to rise due to the opioid epidemic in the USA, namely, the widespread availability and use of fentanyl. Medical examiners and coroners across the country have been subsequently burdened, and with limited resources, some seek alternative triaging processes to identify overdoses. Point-of-care urine dipstick testing at autopsy is one such idea that may be used in various ways to instigate or negate the need for an autopsy or regular forensic toxicology laboratory testing. This study investigated the frequency and estimated quantitative fentanyl and norfentanyl concentrations in the postmortem urine of fentanyl-related accidental overdose deaths, as well as the effectiveness of commercially available point-of-care urine dipstick tests based on such concentrations. A total of 1550 fentanyl-related accidental overdose cases, where both the postmortem peripheral femoral blood and urine were tested, were reviewed. Of these, using sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) laboratory testing, 82 cases (5%) had a positive fentanyl or norfentanyl detection in the blood, while fentanyl or norfentanyl remained undetected in the urine. Furthermore, a comparison of commercially available urine dipstick test cut-offs and authentic casework with estimated urine concentrations revealed that at a fentanyl/norfentanyl cut-off level of 5 ng/mL, 19% of these fentanyl-related accidental overdoses would result in a false negative, 24% at 10 ng/mL, 25% at 20 ng/mL, 51% at 50 ng/mL, and 61% at 100 ng/mL. The study found that the use of urine dipstick tests, as a decision-maker for the initiation of further comprehensive routine toxicology laboratory testing, or to support cause and manner of death determination, leads to both false-positive and false-negative predictions in fentanyl accidental overdoses.

The frequency and chemical phenotype of neighboring plants determine the effects of intraspecific plant diversity.

Associational effects, whereby plants influence the biotic interactions of their neighbors, are an important component of plant-insect interactions. Plant chemistry has been hypothesized to mediate these interactions. The role of chemistry in associational effects, however, has been unclear in part because the diversity of plant chemistry makes it difficult to tease apart the importance and roles of particular classes of compounds. We examined the chemical ecology of associational effects using backcross-bred plants of the Solanum pennellii introgression lines. We used eight genotypes from the introgression line system to establish 14 unique neighborhood treatments that maximized differences in acyl sugars, proteinase inhibitor, and terpene chemical diversity. We found that the chemical traits of the neighboring plant, rather than simply the number of introgression lines within a neighborhood, influenced insect abundance on focal plants. Furthermore, within-chemical class diversity had contrasting effects on herbivore and predator abundances, and depended on the frequency of neighboring plant chemotypes. Notably, we found insect mobility-flying versus crawling-played a key role in insect response to phytochemistry. We highlight that the frequency and chemical phenotype of plant neighbors underlie associational effects and suggest this may be an important mechanism in maintaining intraspecific phytochemical variation within plant populations.

Fluorofentanyl and Novel Synthetic Opioids in Accidental Overdose Deaths.

One of the quickest-growing subclasses of novel psychoactive substances is novel synthetic opioids (NSO), which are categorized as fentanyl analogs (fentalogs) or non-fentanyl opioids that bind to the mu-opioid receptor. Increased detections of NSO have been observed in the United States. However, limited information on their prevalence outside of the East Coast is available. This study details the prevalence of NSO, specifically fluorofentanyl, in the biological and drug paraphernalia specimens of accidental overdose deaths in San Francisco in 2022. A recently developed and validated LC-MS-MS method was utilized for the analysis of over 250 NSO. Out of the 649 accidental overdose deaths in 2022, 617 cases were available for blood analysis, with at least one NSO detected in 48 cases (7.8%). Fentalogs were detected in all 48 cases, with fluorofentanyl being detected in 40 cases. In postmortem femoral blood, estimated concentrations of fluorofentanyl ranged from 0.1 to 8.9 ng/mL, and 0.05 to 85 ng/mL in urine. Polysubstance use with NSO was seen with fentanyl (89.6%), methamphetamine (70.8%), cocaine (33.3%), and heroin (18.8%). NSO, mainly, fluorofentanyl were observed in matched drug paraphernalia. This report documents the migration of fluorofentanyl to the West Coast, specifically California.

Access to community-based eye services in Meru, Kenya: a cross-sectional equity analysis.

BACKGROUND: Over 80% of blindness in Kenya is due to curable or preventable causes and 7.5 m Kenyans currently need eye services. Embedding sociodemographic data collection into screening programmes could help identify the groups facing systematic barriers to care. We aimed to determine the sociodemographic characteristics that were associated with access among patients diagnosed with an eye problem and referred for treatment in the Vision Impact Programme, currently operating in Meru County. METHOD: We used an embedded, pragmatic, cross-sectional design. A list of sociodemographic questions was developed with input from key stakeholders. The final question set included the following domains: age, gender, religion, marital status, disability, education, occupation, income, housing, assets, and health insurance. These were integrated into an app that is used to screen, refer, and check-in (register) participants within a major eye screening programme. We gathered data from 4,240 people who screened positive and were referred to their local outreach treatment clinic. We used logistic regression to identify which groups were facing the greatest barriers to accessing care. RESULTS: A quarter of those screened between April - July 2023 were found to have an eye problem and were referred, however only 46% of these people were able to access care. In our fully adjusted model, at the 0.05 level there were no statistically significant differences in the odds of attendance within the domains of disability, health insurance, housing, income, or religion. Strong evidence (p < 0.001) was found of an association between access and age, gender, and occupation; with males, younger adults, and those working in sales, services and manual jobs the least likely to receive care. CONCLUSIONS: Access to essential eye services is low and unequal in Meru, with less than a third of those aged 18-44 receiving the care they need. Future work should explore the specific barriers faced by this group.

Perianal Fistulizing Crohn's Disease: Utilizing the TOpClass Classification in Clinical Practice to Provide Targeted Individualized Care.

BACKGROUND & AIMS: Perianal fistulation is a challenging phenotype of Crohn's disease, with significant impact on quality of life. Historically, fistulae have been classified anatomically in relation to the sphincter complex, and management guidelines have been generalized, with lack of attention to the clinical heterogenicity seen. The recent 'TOpClass classification system' for perianal fistulizing Crohn's disease (PFCD) addresses this issue, and classifies patients into defined groups, which provide a focus for fistula management that aligns with disease characteristics and patient goals. In this article, we discuss the clinical applicability of the TOpClass model and provide direction on its use in clinical practice. METHODS: An international group of perianal clinicians participated in an expert consensus to define how the TOpClass system can be incorporated into real-life practice. This included gastroenterologists, inflammatory bowel disease surgeons, and radiologists specialized in PFCD. The process was informed by the multi-disciplinary team management of 8 high-volume fistula centres in North America, Europe, and Australia. RESULTS: The process produced position statements to accompany the classification system and guide PFCD management. The statements range from the management of patients with quiescent perianal disease to those with severe PFCD requiring diverting-ostomy and/or proctectomy. The optimization of medical therapies, as well as the use of surgery, in fistula closure and symptom management is explored across each classification group. CONCLUSION: This article provides an overview of the system's use in clinical practice. It aims to enable clinicians to have a pragmatic and patient goal-centered approach to medical and surgical management options for individual patients with PFCD.

Guidance for estimating penetrance of monogenic disease-causing variants in population cohorts.

Penetrance is the probability that an individual with a pathogenic genetic variant develops a specific disease. Knowing the penetrance of variants for monogenic disorders is important for counseling of individuals. Until recently, estimates of penetrance have largely relied on affected individuals and their at-risk family members being clinically referred for genetic testing, a 'phenotype-first' approach. This approach substantially overestimates the penetrance of variants because of ascertainment bias. The recent availability of whole-genome sequencing data in individuals from very-large-scale population-based cohorts now allows 'genotype-first' estimates of penetrance for many conditions. Although this type of population-based study can underestimate penetrance owing to recruitment biases, it provides more accurate estimates of penetrance for secondary or incidental findings. Here, we provide guidance for the conduct of penetrance studies to ensure that robust genotypes and phenotypes are used to accurately estimate penetrance of variants and groups of similarly annotated variants from population-based studies.

In situ via Contact to hBN-Encapsulated Air-Sensitive Atomically Thin Semiconductors.

Establishing reliable electrical contacts to atomically thin materials is a prerequisite for both fundamental studies and applications yet remains a challenge. In particular, the development of contact techniques for air-sensitive monolayers has lagged behind, despite their unique properties and significant potential for applications. Here, we present a robust method to create contacts to device layers encapsulated within hexagonal boron nitride (hBN). This method uses plasma etching and metal deposition to create 'vias' in the hBN with graphene forming an atomically thin etch-stop. The resulting partially fluorinated graphene (PFG) protects the underlying device layer from air-induced degradation and damage during metal deposition. PFG is resistive in-plane but maintains high out-of-plane conductivity. The work function of the PFG/metal contact is tunable through the degree of fluorination, offering opportunities for contact engineering. Using the in situ via technique, we achieve ambipolar contact to air-sensitive monolayer 2H-molybdenum ditelluride (MoTe2) with more than 1 order of magnitude improvement in on-current density compared to previous literature. The complete encapsulation provides high reproducibility and long-term stability. The technique can be extended to other air-sensitive materials as well as air-stable materials, offering highly competitive device performance.

Kidney Function Biomarkers During Extreme Heat Exposure in Young and Older Adults.

This study investigates the effects of extreme heat exposure on kidney function using plasma-based biomarkers in young and older adults.

ACR Appropriateness Criteria® Dizziness and Ataxia: 2023 Update.

Diagnostic evaluation of a patient with dizziness or vertigo is complicated by a lack of standardized nomenclature, significant overlap in symptom descriptions, and the subjective nature of the patient's symptoms. Although dizziness is an imprecise term often used by patients to describe a feeling of being off-balance, in many cases dizziness can be subcategorized based on symptomatology as vertigo (false sense of motion or spinning), disequilibrium (imbalance with gait instability), presyncope (nearly fainting or blacking out), or lightheadedness (nonspecific). As such, current diagnostic paradigms focus on timing, triggers, and associated symptoms rather than subjective descriptions of dizziness type. Regardless, these factors complicate the selection of appropriate diagnostic imaging in patients presenting with dizziness or vertigo. This document serves to aid providers in this selection by using a framework of definable clinical variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

A rapid mixed-methods assessment of Libya's primary care system.

BACKGROUND: Libya has experienced decades of violent conflict that have severely disrupted health service delivery. The Government of National Unity is committed to rebuilding a resilient health system built on a platform of strong primary care. AIM: Commissioned by the government, we set out to perform a rapid assessment of the system as it stands and identify areas for improvement. DESIGN AND SETTING: We used a rapid applied policy explanatory-sequential mixed-methods design, working with Libyan data and Libyan policymakers, with supporting interview data from other primary care policymakers working across the Middle East and North Africa region. METHOD: We used the Primary Health Care Performance Initiative framework to structure our assessment. Review of policy documents and secondary analysis of WHO and World Bank survey data informed a series of targeted policymaker interviews. We used deductive framework analysis to synthesise our findings. RESULTS: We identified 11 key documents and six key policymakers to interview. Libya has strong policy commitments to providing good quality primary care, and a high number of health staff and facilities. Access to services and trust in providers is high. However, a third of facilities are non-operational; there is a marked skew towards axillary and administrative staff; and structural challenges with financing, logistics, and standards has led to highly variable provision of care. CONCLUSION: In reforming the primary care system, the government should consolidate leadership, clarify governance structures and systems, and focus on setting national standards for human resources for health, facilities, stocks, and clinical care.

The use of sequential window acquisition of all theoretical fragment ion spectra (SWATH), a data-independent acquisition high-resolution mass spectrometry approach, in forensic toxicological regimes: A review.

Sequential window acquisition of all theoretical fragment ion spectra (SWATH) is a type of high-resolution mass spectrometry that uses data-independent acquisition. Compared with more targeted acquisition schemes, the power behind this data-independent acquisition technique comes from its ability to mitigate interferences via the use of SWATH acquisition windows (Q1 quadrupole isolation windows) while still obtaining all accurate mass information. However, consistent with high-resolution mass spectrometry techniques, its routine and high throughput implementation in forensic toxicology is limited due to the complex processing power required to effectively manage the large amount of acquired data. It is therefore pivotal to create an efficient and validated identification criterion that confidently reports suspected positive detections as a confirmational technique for final reporting. This review examines all publications that implemented SWATH in a forensic toxicological framework with suggestive best practices and commonly used criteria. Seventeen publications were reviewed for extraction, liquid chromatography and mass spectrometry parameters, and more specifically for all SWATH applicable characteristics including spray voltages, collision energies and spreads, mass error, isotopic ratio difference, retention time error, and library score thresholds. Notwithstanding the challenges SWATH implementation faces for a laboratory, the technique demonstrates its potential to be utilized in routine forensic toxicology testing regimes and aids in the detection of both common and emerging novel drugs simultaneously.

Frontline health workers' experiences of providing care for people living with non-communicable diseases during the COVID-19 pandemic in Ghana: a qualitative study.

BACKGROUND: The COVID-19 pandemic has significantly impacted frontline health workers. However, a neglected dimension of this discourse was the extent to which the pandemic impacted frontline healthcare workers providing non-communicable diseases (NCDs) care. This study aims to understand the experiences of healthcare workers with no prior exposure to pandemics who provided care to people living with NCDs (PLWNCDs). METHODS: A qualitative study design was employed, using a face-to-face in-depth interviews. Interviews were conducted in primary healthcare facilities in three administrative regions of Ghana, representing the Northern, Southern and Middle Belts. Only frontline health workers with roles in providing care for PLWNCDs were included. Purposive snowballing and convenience sampling methods were employed to select frontline health workers. An open-ended interview guide was used to facilitate data collection, and thematic content analysis was used to analyse the data. RESULTS: A total of 47 frontline health workers were interviewed. Overall, these workers experienced diverse patient-driven and organisational challenges. Patient-level challenges included a decline in healthcare utilisation, non-adherence to treatment, a lack of continuity, fear and stigma. At the organisational levels, there was a lack of medical logistics, increased infection of workers and absenteeism, increased workload and burnout, limited motivational packages and inadequate guidelines and protocols. Workers coped and responded to the pandemic by postponing reviews and consultations, reducing inpatient and outpatient visits, changing their prescription practices, using teleconsultation and moving to long-shift systems. CONCLUSION: This study has brought to the fore the experiences that adversely affected frontline health workers and, in many ways, affected the care provided to PLWNCDs. Policymakers and health managers should take these experiences into account in plans to mitigate the impact of future pandemics.

The surge of bromazolam-related fatalities replacing other novel designer benzodiazepines-related fatalities in San Francisco.

BACKGROUND AND AIM: Bromazolam, a novel designer benzodiazepine (NBD), exhibits potent sedative, hypnotic and anxiolytic effects, raising concerns regarding its potential for misuse and fatal outcomes, particularly when combined with opioids such as fentanyl. Despite limited documented fatalities globally, its use poses a significant threat, exacerbated by under-reporting and a lack of routine testing. This study analysed NBD-related deaths in a major US city over a 4-year period. METHODS: Analysis of accidental overdose deaths involving NBDs in San Francisco, CA, USA from 2020 to 2023, was performed utilizing medico-legal death investigations including comprehensive forensic toxicology, pathology and demographic information. San Francisco conducts thorough investigations into all non-natural and sudden unexpected deaths, including routine alcohol and drug testing of decedents under its jurisdiction, including etizolam, flualprazolam, flubromazolam and bromazolam analysis. RESULTS: There was a sudden surge in bromazolam-related deaths, with 44 fatalities documented in 2023, contrasting with relatively fewer deaths related to other NBDs. Bromazolam fatalities frequently involved co-ingestion with opioids, primarily fentanyl, and stimulants such as methamphetamine and cocaine. Demographic characteristics indicated a predominance of males, with a significant proportion lacking fixed addresses. Blood concentrations of bromazolam increased during the study period, suggesting heightened availability and/or purity in the community. CONCLUSION: There was a surge in bromazolam-related deaths during 2023 in San Francisco, CA, USA, contrasting with relatively stable numbers of deaths associated with other NBDs over the preceding years. The findings underscore the urgency for enhanced death investigation, testing and reporting to facilitate targeted harm reduction strategies for individuals at risk of bromazolam-related morbidity and mortality.

Barriers and Opportunities for WHO "Best Buys" Non-communicable Disease Policy Adoption and Implementation From a Political Economy Perspective: A Complexity Systematic Review.

BACKGROUND: Improving the adoption and implementation of policies to curb non-communicable diseases (NCDs) is a major challenge for better global health. The adoption and implementation of such policies remain deficient in various contexts, with limited insights into the facilitating and inhibiting factors. These policies have traditionally been treated as technical solutions, neglecting the critical influence of political economy dynamics. Moreover, the complex nature of these interventions is often not adequately incorporated into evidence for policy-makers. This study aims to systematically review and evaluate the factors affecting NCD policy adoption and implementation. METHODS: We conducted a complex systematic review of articles discussing the adoption and implementation of World Health Organization's (WHO's) "best buys" NCD policies. We identified political economy factors and constructed a causal loop diagram (CLD) program theory to elucidate the interplay between factors influencing NCD policy adoption and implementation. A total of 157 papers met the inclusion criteria. RESULTS: Our CLD highlights a central feedback loop encompassing three vital variables: (1) the ability to define, (re)shape, and pass appropriate policy into law; (2) the ability to implement the policy (linked to the enforceability of the policy and to addressing NCD local burden); and (3) ability to monitor progress, evaluate and correct the course. Insufficient context-specific data impedes the formulation and enactment of suitable policies, particularly in areas facing multiple disease burdens. Multisectoral collaboration plays a pivotal role in both policy adoption and implementation. Effective monitoring and accountability systems significantly impact policy implementation. The commercial determinants of health (CDoH) serve as a major barrier to defining, adopting, and implementing tobacco, alcohol, and diet-related policies. CONCLUSION: To advance global efforts, we recommend focusing on the development of robust accountability, monitoring, and evaluation systems, ensuring transparency in private sector engagement, supporting context-specific data collection, and effectively managing the CDoH. A system thinking approach can enhance the implementation of complex public health interventions.

Rare variant associations with birth weight identify genes involved in adipose tissue regulation, placental function and insulin-like growth factor signalling.

Investigating the genetic factors influencing human birth weight may lead to biological insights into fetal growth and long-term health. Genome-wide association studies of birth weight have highlighted associated variants in more than 200 regions of the genome, but the causal genes are mostly unknown. Rare genetic variants with robust evidence of association are more likely to point to causal genes, but to date, only a few rare variants are known to influence birth weight. We aimed to identify genes that harbour rare variants that impact birth weight when carried by either the fetus or the mother, by analysing whole exome sequence data in UK Biobank participants. We annotated rare (minor allele frequency <0.1%) protein-truncating or high impact missense variants on whole exome sequence data in up to 234,675 participants with data on their own birth weight (fetal variants), and up to 181,883 mothers who reported the birth weight of their first child (maternal variants). Variants within each gene were collapsed to perform gene burden tests and for each associated gene, we compared the observed fetal and maternal effects. We identified 8 genes with evidence of rare fetal variant effects on birth weight, of which 2 also showed maternal effects. One additional gene showed evidence of maternal effects only. We observed 10/11 directionally concordant associations in an independent sample of up to 45,622 individuals (sign test P=0.01). Of the genes identified, IGF1R and PAPPA2 (fetal and maternal-acting) have known roles in insulin-like growth factor bioavailability and signalling. PPARG, INHBE and ACVR1C (all fetal-acting) have known roles in adipose tissue regulation and rare variants in the latter two also showed associations with favourable adiposity patterns in adults. We highlight the dual role of PPARG in both adipocyte differentiation and placental angiogenesis. NOS3, NRK, and ADAMTS8 (fetal and maternal-acting) have been implicated in both placental function and hypertension. Analysis of rare coding variants has identified regulators of fetal adipose tissue and fetoplacental angiogenesis as determinants of birth weight, as well as further evidence for the role of insulin-like growth factors.

Mutant FOXO1 controls an oncogenic network via enhancer accessibility.

Transcriptional dysregulation is a hallmark of diffuse large B cell lymphoma (DLBCL), as transcriptional regulators are frequently mutated. However, our mechanistic understanding of how normal transcriptional programs are co-opted in DLBCL has been hindered by a lack of methodologies that provide the temporal resolution required to separate direct and indirect effects on transcriptional control. We applied a chemical-genetic approach to engineer the inducible degradation of the transcription factor FOXO1, which is recurrently mutated (mFOXO1) in DLBCL. The combination of rapid degradation of mFOXO1, nascent transcript detection, and assessment of chromatin accessibility allowed us to identify the direct targets of mFOXO1. mFOXO1 was required to maintain accessibility at specific enhancers associated with multiple oncogenes, and mFOXO1 degradation impaired RNA polymerase pause-release at some targets. Wild-type FOXO1 appeared to weakly regulate many of the same targets as mFOXO1 and was able to complement the degradation of mFOXO1 in the context of AKT inhibition.

A genetic screen identifies a role for oprF in Pseudomonas aeruginosa biofilm stimulation by subinhibitory antibiotics.

Biofilms are surface-associated communities of bacteria that grow in a self-produced matrix of polysaccharides, proteins, and extracellular DNA (eDNA). Sub-minimal inhibitory concentrations (sub-MIC) of antibiotics induce biofilm formation, potentially as a defensive response to antibiotic stress. However, the mechanisms behind sub-MIC antibiotic-induced biofilm formation are unclear. We show that treatment of Pseudomonas aeruginosa with multiple classes of sub-MIC antibiotics with distinct targets induces biofilm formation. Further, addition of exogenous eDNA or cell lysate failed to increase biofilm formation to the same extent as antibiotics, suggesting that the release of cellular contents by antibiotic-driven bacteriolysis is insufficient. Using a genetic screen for stimulation-deficient mutants, we identified the outer membrane porin OprF and the ECF sigma factor SigX as important. Similarly, loss of OmpA - the Escherichia coli OprF homolog - prevented sub-MIC antibiotic stimulation of E. coli biofilms. Our screen also identified the periplasmic disulfide bond-forming enzyme DsbA and a predicted cyclic-di-GMP phosphodiesterase encoded by PA2200 as essential for biofilm stimulation. The phosphodiesterase activity of PA2200 is likely controlled by a disulfide bond in its regulatory domain, and folding of OprF is influenced by disulfide bond formation, connecting the mutant phenotypes. Addition of reducing agent dithiothreitol prevented sub-MIC antibiotic biofilm stimulation. Finally, activation of a c-di-GMP-responsive promoter follows treatment with sub-MIC antibiotics in the wild-type but not an oprF mutant. Together, these results show that antibiotic-induced biofilm formation is likely driven by a signaling pathway that translates changes in periplasmic redox state into elevated biofilm formation through increases in c-di-GMP.

Analysis of over 250 novel synthetic opioids and xylazine by LC-MS-MS in blood and urine.

Novel Synthetic Opioids (NSO) are frequently found in postmortem (PM) and human performance (HP) forensic toxicology casework, resulting in impairment and fatal overdoses. Developing a broad NSO method benefits public health, as it can be used to identify trends in potent opioid use to develop risk management programs. This project aimed to design a comprehensive, rapid and routine method for the selective analysis of over 250 novel synthetic opioids in blood and urine. This method rapidly extracted 150 µL of blood or urine via protein precipitation followed by size-exclusion filtration, evaporation and reconstitution. Separation and data acquisition were achieved on a 12 min LC-MS-MS method using an F5 column. Data processing was expedited with a custom built-in query created in-house that automated processing and enhanced quality assurance. Validation according to ASB/ANSI Standard 036 was performed and applicability of the method was assessed using proficiency test and authentic casework samples. Assessed in blood and urine qualitatively were 261 unique analytes including fentanyl analogs (fentalogs), nitazenes and other miscellaneous synthetic opioids. As 59 isomeric target analytes were placed into groups due to co-elution, there were 202 distinct acquired targets or target - groups. To demonstrate applicability, 27 proficiency test blood samples received over an approximate 4-year period were analyzed with 126 expected results assessed comprising 25 unique target analytes. Additionally, 617 fatal accidental overdoses within San Francisco in 2022 were retroactively analyzed by this method with almost 10% of cases containing a new NSO substance(s). Such trends and NSO substances were previously unknown in this community.