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BACKGROUND: Suggested anaesthetic dose ranges do not differ by sex, likely because of limited studies comparing sexes. Our objective was to systematically synthesise studies with outcomes of unintended anaesthesia awareness under anaesthesia, intraoperative connected consciousness, time to emergence from anaesthesia, and dosing to achieve adequate depth of anaesthesia, and to compare between females and males. METHODS: Studies were identified from MEDLINE, Embase, and the Cochrane library databases until August 2, 2022. Controlled clinical trials (randomised/non-randomised) and prospective cohort studies that reported outcomes by sex were included. Results were synthesised by random effects meta-analysis where possible, or narrative form. RESULTS: Of the 19 749 studies identified, 64 (98 243 participants; 53 143 females and 45 100 males) were eligible for inclusion, and 44 citations contributed to meta-analysis. Females had a higher incidence of awareness with postoperative recall (33 studies, odds ratio 1.38, 95% confidence interval [CI] 1.09-1.75) and connected consciousness during anaesthesia (three studies, OR 2.09, 95% CI 1.04-4.23) than males. Time to emergence was faster in females, including time to eye-opening (10 studies, mean difference -2.28 min, 95% CI -3.58 to -0.98), and time to response to command (six studies, mean difference -2.84 min, 95% CI -4.07 to -1.62). Data on depth of anaesthesia were heterogenous, limiting synthesis to a qualitative review which did not identify sex differences. CONCLUSIONS: Female sex was associated with a greater incidence of awareness under general anaesthesia, and faster emergence from anaesthesia. These data suggest reappraisal of anaesthetic care, including whether similar drug dosing for females and males represents best care. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022336087.
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Anestesiologia , Anestésicos , Feminino , Humanos , Masculino , Estudos Prospectivos , Anestesia Geral , Anestesiologia/métodosRESUMO
Optical microscopy has vastly expanded the frontiers of structural and functional biology, due to the non-invasive probing of dynamic volumes in vivo. However, traditional widefield microscopy illuminating the entire field of view (FOV) is adversely affected by out-of-focus light scatter. Consequently, standard upright or inverted microscopes are inept in sampling diffraction-limited volumes smaller than the optical system's point spread function (PSF). Over the last few decades, several planar and structured (sinusoidal) illumination modalities have offered unprecedented access to sub-cellular organelles and 4D (3D + time) image acquisition. Furthermore, these optical sectioning systems remain unaffected by the size of biological samples, providing high signal-to-noise (SNR) ratios for objective lenses (OLs) with long working distances (WDs). This review aims to guide biologists regarding planar illumination strategies, capable of harnessing sub-micron spatial resolution with a millimeter depth of penetration.
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Imageamento Tridimensional/instrumentação , Imagem Individual de Molécula/instrumentação , Imagem com Lapso de Tempo/instrumentação , Iluminação , Microscopia de Fluorescência , Razão Sinal-RuídoRESUMO
Papua New Guinea (PNG) is a low-resource country in the South-West Pacific with considerable health care challenges, including a high burden of painful disease. The Essential Pain Management (EPM) educational program was developed to address the challenge of inadequate pain education in PNG and the first workshop was held in 2010. The aims of EPM are to improve pain knowledge, teach a simple system for managing pain, and address local pain management barriers. It is usually delivered as an interactive, multidisciplinary 1-day workshop with an emphasis on developing local solutions to local problems. The program includes an instructor workshop to encourage early handover to local health care workers. Between 2010 and 2018, a total of 42 one-day workshops and 6 instructor workshops were held throughout PNG, and 783 health care workers were trained, as well as 60 instructors. Over two-thirds of the 1-day workshops were taught entirely by local instructors. A shorter version of the workshop, called EPM Lite, was used to train 109 medical and nursing students. Program evaluation has included participant feedback (reaction) and preworkshop and postworkshop tests (knowledge) since inception. Evaluation of behavioral and organizational change has proved more challenging; however, a survey of past participants suggests some important behavioral changes and points to areas for formal research. The uptake of the EPM program in PNG is encouraging and suggests that there is a need for a pain management education program that is simple and easily adopted by local health care workers. There are still significant challenges, including a lack of funding, limited uptake at undergraduate level, the need for more formal evaluation of clinical impact, and the requirement for an all-of-system approach to improve pain management in PNG. Worldwide, EPM has now been taught in more than 60 countries. Our priorities for coming years include support for embedding EPM into health care systems and teaching programs, increased mentorship for instructors, assistance with overcoming local pain management barriers, and development of specific projects that will assess the impact of EPM education on patient outcomes.
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Pessoal de Saúde/educação , Manejo da Dor/métodos , Características Culturais , Atenção à Saúde , Educação Médica , Educação Médica Continuada , Educação em Enfermagem , Geografia , Humanos , Comunicação Interdisciplinar , Aprendizagem , Papua Nova Guiné , Projetos Piloto , Pobreza , Estudantes de Medicina , Estudantes de Enfermagem , EnsinoRESUMO
BACKGROUND: Pelvic exenterations are extensive surgical procedures for locally advanced or recurrent malignancies of the pelvis. However, this is often at the cost of significant morbidity due to perioperative pain, which has been poorly studied. OBJECTIVE: This study aims to review perioperative pain management in patients undergoing pelvic exenteration. DESIGN: This is a retrospective review of patients undergoing pelvic exenteration between January 2013 and December 2014. Data were gathered from medical records and a prospectively maintained database. SETTING: This study was conducted at a single quaternary referral center for pelvic exenteration. PATIENTS: Consecutive patients underwent pelvic exenteration at a single center. INTERVENTIONS: Pelvic exenteration was performed in consecutive patients. MAIN OUTCOMES MEASURES: Primary outcomes were the prevalence of preoperative pain, preoperative opiate use (type, dosage), and postoperative pain (verbal numerical rating scale). Secondary outcomes included the number of pain consultations and correlations between preoperative opiate use, length of stay, and extent of resection (en bloc sacrectomy and nerve excision). RESULTS: Ninety-nine patients underwent pelvic exenteration. Sixty-one patients (61.6%) underwent major nerve resection and/or sacrectomy. Thirty patients (30%) required opiates preoperatively, with a mean daily morphine equivalent of 72.9 mg (SD 65.0 mg). Patients on preoperative opiates were more likely to have worse pain postoperatively and to require higher opiate doses and more pain consultations (9.3 vs 4.8; p < 0.001). Major nerve excision and sacrectomy were not associated with worse postoperative pain. By discharge, 60% still required opiate analgesia. LIMITATIONS: Retrospective study design, the subjective nature of pain assessment because of a lack of valid methods to objectively quantify pain, and the lack of long-term follow-up were limitations of this study. CONCLUSIONS: Perioperative pain is a significant issue among patients undergoing pelvic exenteration. One in three patients require high-dose opiates preoperatively that is associated with worse pain outcomes. Potential areas to improve pain outcomes in these complex patients could include increased use of regional anesthesia, antineuropathic agents, and opiate-sparing techniques. See Video Abstract at http://links.lww.com/DCR/A572.
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Manejo da Dor/métodos , Dor Pós-Operatória/epidemiologia , Exenteração Pélvica/efeitos adversos , Neoplasias Pélvicas/cirurgia , Adulto , Idoso , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Morbidade , Alcaloides Opiáceos/administração & dosagem , Dor Pós-Operatória/terapia , Prevalência , Estudos RetrospectivosRESUMO
Humans communicate through a combination of linguistic and emotional channels, including propositional speech, writing, sign language, music, but also prosodic, facial, and gestural expression. These channels can be interpreted separately or they can be integrated to multimodally convey complex meanings. Neural models of the perception of semantics and emotion include nodes for both functions in the inferior frontal gyrus pars orbitalis (IFGorb). However, it is not known whether this convergence involves a common functional zone or instead specialized subregions that process semantics and emotion separately. To address this, we performed Kernel Density Estimation meta-analyses of published neuroimaging studies of the perception of semantics or emotion that reported activation in the IFGorb. The results demonstrated that the IFGorb contains two zones with distinct functional profiles. A lateral zone, situated immediately ventral to Broca's area, was implicated in both semantics and emotion. Another zone, deep within the ventral frontal operculum, was engaged almost exclusively by studies of emotion. Follow-up analysis using Meta-Analytic Connectivity Modeling demonstrated that both zones were frequently co-activated with a common network of sensory, motor, and limbic structures, although the lateral zone had a greater association with prefrontal cortical areas involved in executive function. The status of the lateral IFGorb as a point of convergence between the networks for processing semantic and emotional content across modalities of communication is intriguing since this structure is preserved across primates with limited semantic abilities. Hence, the IFGorb may have initially evolved to support the comprehension of emotional signals, being later co-opted to support semantic communication in humans by forming new connections with brain regions that formed the human semantic network.
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Área de Broca/fisiologia , Emoções/fisiologia , Vias Neurais/fisiologia , Semântica , Percepção da Fala/fisiologia , Área de Broca/anatomia & histologia , Humanos , Imageamento por Ressonância Magnética , Vias Neurais/anatomia & histologiaAssuntos
Colite Ulcerativa/tratamento farmacológico , Doença de Crohn/tratamento farmacológico , Fármacos Gastrointestinais/uso terapêutico , Infliximab/uso terapêutico , Exposição Materna , Complicações na Gravidez/tratamento farmacológico , Adolescente , Adulto , Criança , Pré-Escolar , Colite Ulcerativa/sangue , Colite Ulcerativa/diagnóstico , Colite Ulcerativa/imunologia , Colonoscopia , Doença de Crohn/imunologia , Quimioterapia Combinada , Feminino , Fármacos Gastrointestinais/imunologia , Fármacos Gastrointestinais/farmacocinética , Humanos , Infliximab/imunologia , Infliximab/farmacocinética , Masculino , Anamnese , Gravidez , Complicações na Gravidez/imunologia , Indução de Remissão/métodos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND AIMS: Cartilage tissue engineering with human mesenchymal stromal cells (hMSC) is promising for allogeneic cell therapy. To achieve large-scale hMSC propagation, scalable microcarrier-based cultures are preferred over conventional static cultures on tissue culture plastic. Yet it remains unclear how microcarrier cultures affect hMSC chondrogenic potential, and how this potential is distinguished from that of tissue culture plastic. Hence, our study aims to compare the chondrogenic potential of human early MSC (heMSC) between microcarrier-spinner and tissue culture plastic cultures. METHODS: heMSC expanded on either collagen-coated Cytodex 3 microcarriers in spinner cultures or tissue culture plastic were harvested for chondrogenic pellet differentiation with empirically determined chondrogenic inducer bone morphogenetic protein 2 (BMP2). Pellet diameter, DNA content, glycosaminoglycan (GAG) and collagen II production, histological staining and gene expression of chondrogenic markers including SOX9, S100ß, MMP13 and ALPL, were investigated and compared in both conditions. RESULTS: BMP2 was the most effective chondrogenic inducer for heMSC. Chondrogenic pellets generated from microcarrier cultures developed larger pellet diameters, and produced more DNA, GAG and collagen II per pellet with greater GAG/DNA and collagen II/DNA ratios compared with that of tissue culture plastic. Moreover, they induced higher expression of chondrogenic genes (e.g., S100ß) but not of hypertrophic genes (e.g., MMP13 and ALPL). A similar trend showing enhanced chondrogenic potential was achieved with another microcarrier type, suggesting that the mechanism is due to the agitated nature of microcarrier cultures. CONCLUSIONS: This is the first study demonstrating that scalable microcarrier-spinner cultures enhance the chondrogenic potential of heMSC, supporting their use for large-scale cell expansion in cartilage cell therapy.
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Cartilagem/metabolismo , Técnicas de Cultura de Células , Terapia Baseada em Transplante de Células e Tecidos/métodos , Condrogênese/fisiologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Engenharia Tecidual/métodos , Fosfatase Alcalina/biossíntese , Proteína Morfogenética Óssea 2/farmacologia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Condrócitos/citologia , Colágeno/metabolismo , DNA/análise , DNA/metabolismo , Glicosaminoglicanos/metabolismo , Humanos , Metaloproteinase 13 da Matriz/biossíntese , Subunidade beta da Proteína Ligante de Cálcio S100/biossíntese , Fatores de Transcrição SOX9/biossíntese , Transplante HomólogoRESUMO
BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) are being investigated as potential cell therapies for many different indications. Current methods of production rely on traditional monolayer culture on tissue-culture plastic, usually with the use of serum-supplemented growth media. However, the monolayer culturing system has scale-up limitations and may not meet the projected hundreds of billions to trillions batches of cells needed for therapy. Furthermore, serum-free medium offers several advantages over serum-supplemented medium, which may have supply and contaminant issues, leading to many serum-free medium formulations being developed. METHODS: We cultured seven MSC lines in six different serum-free media and compared their growth between monolayer and microcarrier culture. RESULTS: We show that (i) expansion levels of MSCs in serum-free monolayer cultures may not correlate with expansion in serum-containing media; (ii) optimal culture conditions (serum-free media for monolayer or microcarrier culture) differ for each cell line; (iii) growth in static microcarrier culture does not correlate with growth in stirred spinner culture; (iv) and that early cell attachment and spreading onto microcarriers does not necessarily predict efficiency of cell expansion in agitated microcarrier culture. CONCLUSIONS: Current serum-free media developed for monolayer cultures of MSCs may not support MSC proliferation in microcarrier cultures. Further optimization in medium composition will be required for microcarrier suspension culture for each cell line.
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Técnicas de Cultura de Células , Terapia Baseada em Transplante de Células e Tecidos/métodos , Meios de Cultura Livres de Soro , Células-Tronco Mesenquimais/citologia , Linhagem Celular , Proliferação de Células , HumanosAssuntos
Extubação/métodos , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/terapia , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Pneumonia Viral/terapia , Aerossóis , Betacoronavirus , COVID-19 , Humanos , Guias de Prática Clínica como Assunto , SARS-CoV-2RESUMO
BACKGROUND: Combination therapy with an inhaled corticosteroid (ICS) and long-acting ß2 agonist (LABA) is recommended for patients with asthma symptomatic on ICS alone. However, there is ongoing debate regarding the risk-benefit ratio of using LABA in asthma. OBJECTIVE: To evaluate the effect of the addition of a novel LABA, vilanterol (VI), to a once-daily ICS, fluticasone furoate (FF), on the risk of severe asthma exacerbations in patients with uncontrolled asthma. METHODS: This randomised double-blind comparative study of variable duration (≥ 24-78 weeks) was designed to finish after 330 events (each patient's first on-treatment severe asthma exacerbation). 2019 patients with asthma aged ≥ 12 years with ≥ 1 recorded exacerbation within 1 year were randomised and received FF/VI 100/25 µg or FF 100 µg, administered once daily in the evening. The primary endpoint was time to first severe exacerbation; secondary endpoints were rate of severe asthma exacerbations per patient per year and change in trough evening forced expiratory volume in 1 s (FEV1) from baseline. RESULTS: Compared with FF, FF/VI delayed the time to first severe exacerbation (HR 0.795, 95% CI 0.642 to 0.985) and reduced the annualised rate of severe exacerbations (rate reduction 25%, 95% CI 5% to 40%). Significantly greater improvements in trough FEV1 (p<0.001) were observed with FF/VI than with FF at weeks 12, 36, 52 and at endpoint. Both treatments were well tolerated with similar rates of treatment-related adverse events and on-treatment serious adverse events. CONCLUSIONS: Once-daily FF/VI reduced the risk of severe asthma exacerbations and improved lung function compared with FF alone, with good tolerability and safety profile in adolescents and adults with asthma currently receiving ICS. CLINICALTRIALSGOV NO: NCT01086384.
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Androstadienos/administração & dosagem , Antiasmáticos/administração & dosagem , Asma/tratamento farmacológico , Álcoois Benzílicos/administração & dosagem , Clorobenzenos/administração & dosagem , Glucocorticoides/administração & dosagem , Administração por Inalação , Adolescente , Adulto , Androstadienos/efeitos adversos , Androstadienos/uso terapêutico , Antiasmáticos/efeitos adversos , Antiasmáticos/uso terapêutico , Álcoois Benzílicos/efeitos adversos , Álcoois Benzílicos/uso terapêutico , Criança , Clorobenzenos/efeitos adversos , Clorobenzenos/uso terapêutico , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Volume Expiratório Forçado/efeitos dos fármacos , Glucocorticoides/efeitos adversos , Glucocorticoides/uso terapêutico , Humanos , Masculino , Risco , Resultado do TratamentoRESUMO
INTRODUCTION: An ST-elevation myocardial infarction (STEMI) can portend significant morbidity and mortality to the patient and therefore must be rapidly diagnosed by an emergency medicine (EM) physician. The primary aim of this study is to determine whether EM physicians are more or less likely to accurately diagnose STEMI on an electrocardiogram (ECG) if they are blinded to the ECG machine interpretation as opposed to if they are provided the ECG machine interpretation. METHODS: We performed a retrospective chart review of adult patients over 18 years of age admitted to our large, urban tertiary care center with a diagnosis of STEMI from January 1, 2016, to December 31, 2017. From these patients' charts, we selected 31 ECGs to create a quiz that was presented twice to a group of emergency physicians. The first quiz contained the 31 ECGs without the computer interpretations revealed. The second quiz, presented to the same physicians 2 weeks later, contained the same set of ECGs with the computer interpretations revealed. Physicians were asked "Based on the ECG above, is there a blocked coronary artery present causing a STEMI?" RESULTS: Twenty-five EM physicians completed two 31-question ECG quizzes for a total of 1550 ECG interpretations. On the first quiz with computer interpretations blinded, the overall sensitivity in identifying a "true STEMI" was 67.2% with an overall accuracy of 65.6%. On the second quiz in which the ECG machine interpretation was revealed, the overall sensitivity was 66.4% with an accuracy of 65.8 % in correctly identifying a STEMI. The differences in sensitivity and accuracy were not statistically significant. CONCLUSION: This study demonstrated no significant difference in physicians blinded versus those unblinded to computer interpretations of possible STEMI.
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Oclusão Coronária , Serviços Médicos de Emergência , Médicos , Infarto do Miocárdio com Supradesnível do Segmento ST , Adulto , Humanos , Adolescente , Infarto do Miocárdio com Supradesnível do Segmento ST/diagnóstico , Estudos Retrospectivos , EletrocardiografiaRESUMO
Circulating melatonin is elevated in women with polycystic ovary syndrome (PCOS); whether circadian disruptions coincide with sleep disturbances in women with PCOS or their symptom severity is unclear. The objective of this observational pilot study was to determine whether altered patterns of melatonin excretion are associated with reduced sleep quality in women with versus without PCOS. Participants underwent a clinical assessment, transvaginal ultrasound, and reproductive hormone testing. Morning and evening urine samples were assayed for urinary 6-sulfatoxymelatonin (MEL) as a proxy for melatonin production. The night (morning MEL)-to-day (evening MEL) ratio, or N:D ratio, was determined to approximate the rhythm of MEL production. Sleep quality and duration were assessed using the Pittsburgh Sleep Quality Index (PSQI) and wrist actigraphy. No differences were detected in overnight MEL, daytime MEL, or the N:D ratio in participants with PCOS versus controls. The PCOS group experienced reduced weekend sleep efficiency vs. controls (81% vs. 88% p < 0.05). The number of follicles per ovary (FNPO) was positively associated with overnight MEL (r = 0.359, p < 0.05). Weekend sleep time and overnight MEL concentrations were dependent on PCOS status. Therefore, diagnostic features of PCOS were associated with MEL production and sleep disturbances, suggesting that women with a more severe clinical presentation of PCOS may be more likely to experience altered MEL production or sleep disturbances.
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Current guidelines recommend adding a long-acting inhaled ß(2)-agonist (LABA) to inhaled corticosteroids (ICS) in patients with uncontrolled asthma. This study evaluated the novel, once-daily LABA vilanterol trifenatate (VI) in asthma patients who remained symptomatic despite existing ICS therapy. The study involved a randomised, double-blind, placebo-controlled trial of VI (3, 6.25, 12.5, 25 and 50 µg), administered once daily in the evening by dry powder inhaler for 28 days, in asthma patients aged ≥ 12 yrs symptomatic on current ICS therapy. The primary end-point was trough (24 h post-dose) forced expiratory volume in 1 s (FEV(1)); secondary end-points were weighted mean FEV(1), peak expiratory flow (PEF), symptom-/rescue-free 24-h periods, and safety. A significant relationship was observed between VI dose and improvements in trough FEV(1) (p=0.037). Statistically significant increases in mean trough FEV(1), relative to placebo, were documented for VI 12.5-50 µg (121-162 mL; p ≤ 0.016). Dose-related effects of VI were observed on weighted mean (0-24 h) FEV(1), morning/evening PEF, and symptom-/rescue-free 24-h periods. All doses of VI were well tolerated with low incidences of recognised LABA-related adverse events (tremor 0-2%; palpitations 0-2%; glucose effects 0-1%; potassium effects 0-<1%). Once-daily VI 12.5-50 µg resulted in prolonged bronchodilation of at least 24 h with good tolerability in asthma patients receiving ICS. Based on the overall efficacy and adverse event profile from this study, the optimum dose of VI appears to be 25 µg.
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Corticosteroides/uso terapêutico , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Álcoois Benzílicos/uso terapêutico , Clorobenzenos/uso terapêutico , Administração por Inalação , Adulto , Asma/fisiopatologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Função Respiratória , Adulto JovemRESUMO
The underwater adhesive prowess of aquatic mussels has been largely attributed to the abundant post-translationally modified amino acid l-3,4-dihydroxyphenylalanine (Dopa) in mussel foot proteins (MFPs) that make up their adhesive threads. More recently, it has been suggested that during thread fabrication, MFPs form intermediate fluidic phases such as liquid crystals or coacervates regulated by a liquid-liquid phase separation (LLPS) process. Here, it is shown that Dopa plays another central role during mussel fiber formation, by enabling LLPS of Pvfp-5ß, a main MFP of the green mussel Perna viridis. Using residue-specific substitution of Tyrosine (Tyr) for Dopa during recombinant expression, Dopa-substituted Pvfp-5ß is shown to exhibit LLPS under seawater-like conditions, whereas the Tyr-only version forms insoluble aggregates. Combining quantum chemistry calculations and solution NMR, a transient H-bonding network requiring the two hydroxyl groups of Dopa is found to be critical to enable LLPS in Dopa-mutated Pvfp-5ß. Overall, the study suggests that Dopa plays an important role in regulating LLPS of MFPs, which may be critical to concentrate the adhesive proteins at the plaque/substrate interface and therefore produce a more robust adhesive. The findings also provide molecular-level lessons to guide biomanufacturing of protein-based materials such as bioadhesives and load-bearing fibers.
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Bivalves , Di-Hidroxifenilalanina , Adesivos/química , Aminoácidos , Animais , Bivalves/química , Bivalves/genética , Di-Hidroxifenilalanina/metabolismo , Proteínas/químicaRESUMO
In vivo quantitative assessment of structural and functional biomarkers is essential for characterizing the pathophysiology of congenital disorders. In this regard, fixed tissue analysis has offered revolutionary insights into the underlying cellular architecture. However, histological analysis faces major drawbacks with respect to lack of spatiotemporal sampling and tissue artifacts during sample preparation. This study demonstrates the potential of light sheet fluorescence microscopy (LSFM) as a non-invasive, 4D (3days + time) optical sectioning tool for revealing cardiac mechano-transduction in zebrafish. Furthermore, we have described the utility of a scale and size-invariant feature detector, for analyzing individual morphology of fused cardiomyocyte nuclei and characterizing zebrafish ventricular contractility.
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BACKGROUND: Antimicrobial resistance is a significant global public health threat. However, the impact of sourcing potentially substandard and falsified antibiotics via the internet remains understudied, particularly in the context of access to and quality of common antibiotics. In response, this study conducted a multifactor quality and safety analysis of antibiotics sold and purchased via online pharmacies that did not require a prescription. OBJECTIVE: The aim of this paper is to identify and characterize "no prescription" online pharmacies selling 5 common antibiotics and to assess the quality characteristics of samples through controlled test buys. METHODS: We first used structured search queries associated with the international nonproprietary names of amoxicillin, azithromycin, amoxicillin and clavulanic acid, cephalexin, and ciprofloxacin to detect and characterize online pharmacies offering the sale of antibiotics without a prescription. Next, we conducted controlled test buys of antibiotics and conducted a visual inspection of packaging and contents for risk evaluation. Antibiotics were then analyzed using untargeted mass spectrometry (MS). MS data were used to determine if the claimed active pharmaceutical ingredient was present, and molecular networking was used to analyze MS data to detect drug analogs as well as possible adulterants and contaminants. RESULTS: A total of 109 unique websites were identified that actively advertised direct-to-consumer sale of antibiotics without a prescription. From these websites, we successfully placed 27 orders, received 11 packages, and collected 1373 antibiotic product samples. Visual inspection resulted in all product packaging consisting of pill packs or blister packs and some concerning indicators of potential poor quality, falsification, and improper dispensing. Though all samples had the presence of stated active pharmaceutical ingredient, molecular networking revealed a number of drug analogs of unknown identity, as well as known impurities and contaminants. CONCLUSIONS: Our study used a multifactor approach, including web surveillance, test purchasing, and analytical chemistry, to assess risk factors associated with purchasing antibiotics online. Results provide evidence of possible safety risks, including substandard packaging and shipment, falsification of product information and markings, detection of undeclared chemicals, high variability of quality across samples, and payment for orders being defrauded. Beyond immediate patient safety risks, these falsified and substandard products could exacerbate the ongoing public health threat of antimicrobial resistance by circulating substandard product to patients.