Partial Nicotine Reduction and E-Cigarette Users' Puffing Behaviors Among Adults Aged 21 to 35 Years: A Randomized Crossover Clinical Trial.

Importance: The advent of salt-based, high-nicotine electronic nicotine delivery systems [e-cigarettes] has contributed to their epidemic use among young people in the US, necessitating the need for policies to address the addictiveness of these products.

Objective: To evaluate the effect of partial nicotine reduction on new-generation e-cigarette users' puffing behaviors.

Design, Setting, And Participants: This randomized crossover clinical trial was conducted at the Clinical Research Lab for Tobacco Smoking at Florida International University in Miami between April 15, 2022, and October 17, 2023.

Development and validation of a method for analysis of 25 cannabinoids in oral fluid and exhaled breath condensate.

Currently, there is a significant demand in forensic toxicology for biomarkers of cannabis exposure that, unlike ∆-tetrahydrocannabinol, can reliably indicate time and frequency of use, be sampled with relative ease, and correlate with impairment. Oral fluid (OF) and exhaled breath condensate (EBC) are alternative, non-invasive sample matrices that hold promise for identifying cannabis exposure biomarkers. OF, produced by salivary glands, is increasingly utilized in drug screening due to its non-invasive collection and is being explored as an alternative matrix for cannabinoid analysis.

Ferrate(VI) mediated degradation of the potent cyanotoxin, cylindrospermopsin: Kinetics, products, and toxicity.

The presence of cylindrospermopsin (CYN), a potent cyanotoxin, in drinking water sources poses a tremendous risk to humans and the environment. Detailed kinetic studies herein demonstrate ferrate(VI) (FeO, Fe(VI)) mediated oxidation of CYN and the model compound 6-hydroxymethyl uracil (6-HOMU) lead to their effective degradation under neutral and alkaline solution pH. A transformation product analysis indicated oxidation of the uracil ring, which has functionality critical to the toxicity of CYN.

A culturally appropriate method for validating self-reported drug administration among indigenous people who use injection drugs.

Compared with other racial/ethnic groups in the United States (US), American Indians/Alaska Natives have one of the fastest climbing rates of drug overdose deaths involving stimulants. Validating the substances self-reported by Indigenous people who use injection drugs (IPWIDs) can present logistical and cultural challenges. While the collection of biospecimens (e.

Evaluation of Pretreatment and Extraction Parameters for the Analysis of Fentanyl in Hair Using Statistical Design of Experiments (DoE).

Optimal methods for hair analysis are often debated. Previous work in this laboratory demonstrated that the statistical technique known as Design of Experiments (DoE) is useful for such optimization. DoE evaluates both the individual roles and the combinatorial associations among multiple independent variables (i.

Evaluation of extraction parameters in authentic hair reference material using statistical design of experiments.

Optimal methods for forensic hair analysis are often debated, especially regarding extraction parameters that include incubation time, temperature, and size of extracted hair particles. To assess hair pretreatment parameters for analysis of drugs of abuse, the statistical technique known as Design of Experiments (DoE) is useful. DoE evaluates both the individual roles and the combinatorial associations between multiple variables and overall drug extraction efficiency.

DNA Aptamer-Cyanine Complexes as Generic Colorimetric Small-Molecule Sensors.

Aptamers are promising biorecognition elements for sensors. However, aptamer-based assays often lack the requisite levels of sensitivity and/or selectivity because they typically employ structure-switching aptamers with attenuated affinity and/or utilize reporters that require aptamer labeling or which are susceptible to false positives. Dye-displacement assays offer a label-free, sensitive means for overcoming these issues, wherein target binding liberates a dye that is complexed with the aptamer, producing an optical readout.

Comprehensive analysis of synthetic cannabinoids and metabolites in oral fluid by online solid-phase extraction coupled to liquid chromatography-triple quadrupole-mass spectrometry.

The class of novel psychoactive substances known as synthetic cannabinoids (SC) includes illicit compounds that are sprayed on plant material and smoked or sold as liquids to be vaporized in e-cigarettes. In toxicological analysis of SC, fast analytical methods are needed for the detection and confirmation of parent drugs and metabolites at very low levels. While various analytical methods have been developed for SC in blood and urine, few are available for alternative matrices such as oral fluid (OF).

Assessing Hair Decontamination Protocols for Diazepam, Heroin, Cocaine and Δ9-Tetrahydrocannabinol by Statistical Design of Experiments.

Prior to toxicological analysis, hair as a matrix requires pre-treatment measures including decontamination, homogenization and extraction. Decontamination is performed to differentiate between drug present from superficial deposition and drug incorporated from systemic distribution following ingestion. There are many methods for decontamination of hair samples, mostly developed by empirically using a traditional "one factor at a time" approach, in which one independent variable at a time is changed to observe the effect on the dependent variable.

Development of a DNA Adductome Mass Spectral Database.

Mass spectrometry-based DNA adductomics is an emerging approach for the human biomonitoring of hazardous chemicals. A mass spectral database of DNA adducts will be created for the scientific community to investigate the associations between chemical exposures, DNA damage, and disease risk.

Conodipine-P1-3, the First Phospholipases A Characterized from Injected Cone Snail Venom.

The phospholipase A (PLAs) superfamily are ubiquitous small enzymes that catalyze the hydrolysis of phospholipids at the sn-2 ester bond. PLAs in the venom of cone snails (conodipines, Cdpi) are composed of two chains termed as alpha and beta subunits. Conodipines are categorized within the group IX of PLAs.

Separation and Identification of Isomeric and Structurally Related Synthetic Cannabinoids Using 2D Liquid Chromatography and High Resolution Mass Spectrometry.

Novel psychoactive substances (NPS) are emerging drugs of abuse that are variations of existing compounds intended to cause a CNS psychotropic effect. Some NPS are so comparable in structure and physicochemical properties that they co-elute using traditional single column chromatographic techniques and therefore will not be detected as individual compounds. 2D liquid chromatography (2D-LC) has demonstrated applicability in difficult separations of small molecules and compounds in complex mixtures.

LC-MS/MS based detection and characterization of covalent glutathione modifications formed by reactive drug of abuse metabolites.

Conjugation with the tripeptide glutathione (GSH) is a common mechanism of detoxification of many endogenous and exogenous compounds. This phenomenon typically occurs through the formation of a covalent bond between the nucleophilic free thiol moiety of GSH and an electrophilic site on the compound of interest. While GSH adducts have been identified for many licit drugs, there is a lack of information on the ability of drugs of abuse to adduct GSH.

Fundamental study of the ultrasonic induced degradation of the popular antihistamine, diphenhydramine (DPH).

Diphenhydramine (DPH) the active ingredient in Benadryl, has been detected in streams, rivers and other surface water sources. As a bioactive compound, DPH impacts human health even at low concentrations. Ultrasonic irradiation at 640 kHz leads to the rapid degradation of DPH in aqueous solution.

Rapid quantitative analysis of methylphenidate and ritalinic acid in oral fluid by liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS).

Methylphenidate (MPH), which is metabolized into ritalinic acid (RA), is an amphetamine derivative largely used in the treatment of attention-deficit hyperactivity disorder, a neurological condition commonly diagnosed in early childhood. Ensuring that patients comply with clinical treatment is crucial and compliance is generally monitored in blood or urine specimens which, especially in the case of children, can be challenging to obtain on a repetitive basis. Here we report validation of a specific, non-invasive, and rapid dilute-and-shoot analytical method for the detection and quantitation of MPH and RA in oral fluid (OF).

Proteomic Analysis of Thiol Modifications and Assessment of Structural Changes in Hemoglobin Induced by the Aniline Metabolites N-Phenylhydroxylamine and Nitrosobenzene.

MS-based proteomic analysis was combined with in silico quantum mechanical calculations to improve understanding of protein adduction by N-phenylhydroxylamine (PhNHOH) and nitrosobenzene (NOB), metabolic products of aniline. In vitro adduction of model peptides containing nucleophilic sidechains (Cys, His, and Lys) and selected proteins (bovine and human hemoglobin and β-lactoglobulin-A) were characterized. Peptide studies identified the Cys thiolate as the most reactive nucleophile for these metabolites, a result consistent with in silico calculations of reactivity parameters.

Isolation and characterization of Conohyal-P1, a hyaluronidase from the injected venom of Conus purpurascens.

Unlabelled: Hyaluronidases are ubiquitous enzymes commonly found in venom and their main function is to degrade hyaluran, which is the major glycosaminoglycan of the extracellular matrix in animal tissues. Here we describe the purification and characterization of a 60kDa hyaluronidase found in the injected venom from Conus purpurascens, Conohyal-P1. Using a combined strategy based on transcriptomic and proteomic analysis, we determined the Conohyal-P1 sequence.

Diabetes Prevalence in Relation to Serum Concentrations of Polychlorinated Biphenyl (PCB) Congener Groups and Three Chlorinated Pesticides in a Native American Population.

Background: Exposure to persistent organic pollutants (POPs) is known to increase risk of diabetes.

Objective: To determine which POPs are most associated with prevalence of diabetes in 601 Akwesasne Native Americans.

Methods: Multiple logistic regression analysis was used to assess associations between quartiles of concentrations of 101 polychlorinated biphenyl (PCBs) congeners, congener groups and three chlorinated pesticides [dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and mirex] with diabetes.

Changes in persistent organic pollutant levels from adolescence to young adulthood.

Elimination rates and their corresponding half-lives are conceptually important and intuitively accessible pharmacokinetic measures of toxicant elimination, but regression-based estimates are biased proportional to the degree of continuing (background) exposure. We propose an alternative estimator, the censored normal regression model, which uses all observations, but treats individuals whose initial level failed to exceed their follow-up level as censored observations to weight the regression estimates from those that declined between blood draws. In this manner, we derive the intrinsic elimination rate, the elimination rate free from ongoing exposure, as a parameter in a regression with an unobserved, latent dependent variable.

Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.

Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (OH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.

Relationships of polychlorinated biphenyls and dichlorodiphenyldichloroethylene (p,p'-DDE) with testosterone levels in adolescent males.

Background: Concern persists over endocrine-disrupting effects of persistent organic pollutants (POPs) on human growth and sexual maturation. Potential effects of toxicant exposures on testosterone levels during puberty are not well characterized.

Objectives: In this study we evaluated the relationship between toxicants [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p´-DDE), hexachlorobenzene (HCB), and lead] and testosterone levels among 127 Akwesasne Mohawk males 10 to < 17 years of age with documented toxicant exposures.

Covalent thiol adducts arising from reactive intermediates of cocaine biotransformation.

Exposure to cocaine results in the depletion of hepatocellular glutathione and macromolecular protein binding in humans. Such cocaine-induced responses have generally been attributed to oxidative stress and reactive metabolites resulting from oxidative activation of the cocaine tropane nitrogen. However, little conclusive data exists on the mechanistic pathways leading to protein modification or the structure and specificity of cocaine-derived adduction products.

Covalent adduction of nitrogen mustards to model protein nucleophiles.

Protein adducts have the potential to serve as unique biomarkers of exposure to compounds of interest. Many xenobiotics (or their metabolites) are electrophilic and therefore reactive with nucleophilic amino acid residues on proteins. Nitrogen mustards are reactive xenobiotics with potential use as chemical warfare agents (CWA) or agents of terrorist attack, in addition to being employed as chemotherapeutic agents.