Case Report: Risk Factors Associated with Mortality in Adults with Burkholderia Pseudomallei Bacteremia: A Retrospective Case Series of Melioidosis in Cambodia.

In resource-scarce settings, melioidosis is associated with up to 80% mortality. Studies of melioidosis in Cambodia report primarily on pediatric populations with localized infection; however, literature describing Cambodian adults with severe melioidosis is lacking. We present a case series of 35 adults with sequence-confirmed Burkholderia pseudomallei bacteremia presenting to a provincial referral hospital in rural Cambodia. More than 90% of the patients had diabetes, an important risk factor for developing melioidosis. Inappropriate antimicrobial therapy was significantly associated with lower odds of survival. Improved diagnostic testing and greater access to first-line antibiotics for acute melioidosis treatment present potential targets for intervention to reduce mortality associated with this disease in resource-limited settings.

Screening and Retaining Adolescents Recruited Through Social Media: Secondary Analysis from a Longitudinal Clinical Trial.

BACKGROUND: Social media has become a popular method to recruit participants, particularly for studies with hard-to-reach populations. These studies still face challenges in data quality and, for longitudinal studies, sample retention. However, in addition to aiding in recruitment, social media platforms can help researchers with participant verification and tracking procedures during the study. There is limited previous research describing how longitudinal studies can use social media to screen and retain participants. OBJECTIVE: This paper describes strategies implemented to screen and retain a nationwide sample of sexual minority youth who were recruited through social media platforms for a longitudinal study testing a drug abuse prevention program. METHODS: Our screening strategies for participants included collecting necessary demographic information (name, phone, email, and social media accounts), verifying this information using publicly available web-based records, and sending confirmation emails to ensure working email addresses and correct dates of birth. Retention strategies included communications designed to develop positive participant relationships, incentives for survey completion, regular updating of participant contact information, targeting hard-to-reach participants, and using social media as an alternative means of contacting participants. RESULTS: During enrollment, although the only demographic data required were a phone number and an email address, 87.58% (1065/1216) of participants provided their Instagram as an alternative means of contact. This form of alternative communication remains the most preferred with 87.40% (1047/1198) of participants continuing to provide an Instagram username as of January 2023, about 3 years after recruitment began. In comparison, other alternative means of contact (eg, Facebook and alternative email) were provided by only 6.43% (77/1198) to 56.18% (673/1198) of participants. Direct messaging on Instagram was used to successfully confirm participant identity, remind participants to take annual follow-up surveys, and update lost participant contact information. Screening and retention strategies used in the study have helped achieve 96.30% (1171/1216) to 96.79% (1177/1216) sample retention across 3 waves of data collection. CONCLUSIONS: Though social media can be a helpful tool to recruit participants, attrition and participant authenticity difficulties may be associated with this method. Screening and retention strategies can be implemented to improve retention. Internet searches are effective for screening youth to ensure they meet eligibility requirements. Additionally, social media-Instagram in this study-can help to track and locate participants who do not respond to traditional contact methods. TRIAL REGISTRATION: ClinicalTrials.gov NCT03954535; https://clinicaltrials.gov/study/NCT03954535.

Ibero-Panamerican Federation of Periodontology Delphi study on the trends of periodontology and periodontics by the year 2030. A Latin American consensus.

BACKGROUND AND OBJECTIVE: As elsewhere in the world, the prevalence of periodontitis in stages I-II is high in the Latin American population, this scenario emphasizes the need for identification of urgent needs for allocating adequate resources to provide diagnosis, prevention, and treatment of these diseases. The aim of this Delphi study was to predict the trends in periodontology/periodontics in the Latin American region by the year 2030. METHODS: A steering committee and an advisory group of experts in periodontology/periodontics were selected from 16 countries. An open questionnaire of 60 questions was validated and used following the Delphi methodology. RESULTS: Two hundred and twenty-five experts from Latin America answered the two rounds of the questionnaire. Moderate to strong consensus was reached on 45 questions (75%). The prediction was that the prevalence of gingivitis and periodontitis in stages I and II will be maintained, the importance of the link with systemic diseases will increase, and the impact of prevention and periodontal treatment will also increase, mainly in the private sector. There was a strong consensus that plastic and regenerative surgical procedures will increase, as well as the demand for training in the specialty of periodontology. CONCLUSIONS: The present study has provided relevant and useful information on predictions in periodontology/periodontics in Latin America, with important level of consensus among experts. It has been predicted that periodontitis will still be a highly prevalent disease, and its links with other medical conditions should demand more attention by health authorities to develop adequate prevention and management policies and strategies.

Laser absorption spectroscopy measurements of different pulmonary oxygen gas concentrations in transmittance and remittance geometry: phantom study.

Significance: The gas in scattering media absorption spectroscopy (GASMAS) technique has the potential for continuous, clinical monitoring of preterm infant lung function, removing the need for X-ray diagnosis and reliance on indirect and relatively slow measurement of blood oxygenation. Aim: We aim to determine the optimal source-detector configuration for reliable pathlength calculation and to estimate the oxygen gas concentration inside the lung cavities filled with humidified gas with four different oxygen gas concentrations ranging between 21% and 100%. Approach: Anthropomorphic optical phantoms of neonatal thorax with two different geometries were used to acquire GASMAS signals, for 30 source-detector configurations in transmittance and remittance geometry of phantoms in two sizes. Results: The results show that an internal light administration is more likely to provide a high GASMAS signal-to-noise ratio (SNR). In general, better SNRs were obtained with the smaller set of phantoms. The values of pathlength and O2 concentrations calculated with signals from the phantoms with optical properties at 820 nm exhibit higher variations than signals from the phantoms with optical properties at 764 nm. Conclusion: Our study shows that, by moving the source and detector over the thorax, most of the lung volumes can potentially be assessed using the GASMAS technique.

National dengue surveillance, Cambodia 2002-2020.

Global dengue incidence has increased dramatically over the past few decades from approximately 500 000 reported cases in 2000 to over 5 million in 2019. This trend has been attributed to population growth in endemic areas, rapid unplanned urbanization, increasing global connectivity, and climate change expanding the geographic range of the Aedes spp. mosquito, among other factors. Reporting dengue surveillance data is key to understanding the scale of the problem, identifying important changes in the landscape of disease, and developing policies for clinical management, vector control and vaccine rollout. However, surveillance practices are not standardized, and data may be difficult to interpret particularly in low- and middle-income countries with fragmented health-care systems. The latest national dengue surveillance data for Cambodia was published in 2010. Since its publication, the country experienced marked changes in health policies, population demographics, climate and urbanization. How these changes affected dengue control remains unknown. In this article, we summarize two decades of policy changes, published literature, country statistics, and dengue case data collected by the Cambodia National Dengue Control Programme to: (i) identify important changes in the disease landscape; and (ii) derive lessons to inform future surveillance and disease control strategies. We report that while dengue case morbidity and mortality rates in Cambodia fell between 2002 and 2020, dengue incidence doubled and age at infection increased. Future national surveillance, disease prevention and treatment, and vector control policies will have to account for these changes to optimize disease control.

Le taux d'incidence de la dengue dans le monde a considérablement augmenté au cours des dernières décennies, passant d'environ 500 000 cas notifiés en 2000 à plus de 5 millions en 2019. Cette tendance est attribuée à la croissance démographique dans les zones d'endémie, à l'urbanisation rapide non planifiée, au développement de la connectivité à l'échelle internationale, ainsi qu'au changement climatique, qui agrandit le territoire géographique du moustique Aedes spp., entre autres. La communication des données de surveillance de la dengue est essentielle pour comprendre l'étendue du problème, identifier les principales variations de contexte entourant la maladie et mettre au point des politiques pour la prise en charge clinique, la lutte contre les vecteurs et le déploiement des vaccins. Les pratiques en matière de surveillance ne sont toutefois pas standardisées et les données peuvent être difficiles à interpréter, surtout dans les pays à revenu faible et intermédiaire où les systèmes de soins de santé sont fragmentés. Les données de surveillance les plus récentes concernant la dengue au Cambodge ont été publiées en 2010. Depuis leur publication, le pays a subi de profondes mutations au niveau des politiques de santé, de l'évolution démographique, du climat et de l'urbanisation. L'impact de ces mutations sur la lutte contre la dengue reste à établir. Dans le présent article, nous résumons deux décennies d'amendements politiques, de documentation, de statistiques nationales et d'informations collectées sur les cas par le programme cambodgien de lutte contre la dengue afin de: (i) définir les changements importants survenus dans le contexte entourant la maladie; mais aussi (ii) tirer des leçons en vue d'élaborer, à l'avenir, des stratégies de surveillance et de lutte contre la maladie. Nous signalons qu'en dépit d'une baisse des taux de morbidité et de mortalité liés aux cas de dengue entre 2002 et 2020 au Cambodge, son incidence a doublé et l'âge des patients au moment de l'infection a augmenté. Les futures politiques nationales de surveillance, de prévention et de traitement de la dengue, mais aussi de lutte contre ses vecteurs, devront tenir compte de ces changements de façon à mieux maîtriser la maladie.

La incidencia del dengue a nivel mundial ha aumentado considerablemente en las últimas décadas, desde aproximadamente 500 000 casos notificados en el año 2000 a más de 5 millones en 2019. Esta tendencia se ha atribuido al crecimiento de la población en zonas endémicas, a una urbanización rápida y no planificada, al aumento de la conectividad a nivel mundial y al cambio climático, que está permitiendo una distribución geográfica más amplia del mosquito Aedes spp., entre otros factores. Para comprender la magnitud del problema resulta clave la notificación de datos sobre vigilancia del dengue, la identificación de cambios importantes dentro del escenario de la enfermedad, la creación de políticas enfocadas a la gestión clínica, así como el control de vectores y la implantación de la vacuna. Sin embargo, las prácticas sobre vigilancia no están estandarizadas y es posible que sea difícil interpretar los datos, especialmente en países con ingresos medios y bajos, que cuentan con sistemas fragmentados de atención sanitaria. Los datos nacionales más recientes sobre vigilancia del dengue en Camboya se publicaron en 2010. Desde su publicación, el país experimentó cambios significativos en las políticas sanitarias, la demografía de la población, el clima y la urbanización. Aún no se sabe cómo afectaron dichos cambios al control del dengue. En el presente artículo, resumimos dos décadas de cambios políticos, de bibliografía publicada, de datos estadísticos a nivel nacional y datos sobre casos de dengue recopilados por el programa nacional de control de dengue en Camboya, con el fin de: (i) identificar cambios importantes en el escenario de la enfermedad; y (ii) extraer conclusiones para orientar futuras estrategias sobre vigilancia y control de la enfermedad. Informamos de que, aunque las tasas de morbilidad y mortalidad de los casos de dengue en Camboya descendieron entre 2002 y 2020, la incidencia del dengue se duplicó y la edad de infección aumentó. Las futuras políticas nacionales sobre vigilancia, prevención y tratamiento de la enfermedad y control de vectores deberán tener en cuenta estos cambios para optimizar el control de la enfermedad.

Dengue in Cambodia 2002-2020: Cases, Characteristics and Capture by National Surveillance.

Objective: Data from 19 years of national dengue surveillance in Cambodia (2002-2020) were analyzed to describe trends in dengue case characteristics and incidence. Methods: Generalized additive models were fitted to dengue case incidence and characteristics (mean age, case phenotype, fatality) over time. Dengue incidence in a pediatric cohort study (2018-2020) was compared to national data during the same period to evaluate disease under-estimation by national surveillance. Findings: During 2002-2020, there were 353,270 cases of dengue (average age-adjusted incidence 1.75 cases/1,000 persons/year) recorded in Cambodia, with an estimated 2.1-fold increase in case incidence between 2002 and 2020 (slope = 0.0058, SE = 0.0021, p = 0.006). Mean age of infected individuals increased from 5.8 years in 2002 to 9.1 years in 2020 (slope = 0.18, SE = 0.088, p <0.001); case fatality rates decreased from 1.77% in 2002 to 0.10% in 2020 (slope = -0.16, SE = 0.0050, p <0.001). When compared to cohort data, national data under-estimated clinically apparent dengue case incidence by 5.0-fold (95% CI 0.2 - 26.5), and overall dengue case incidence (both apparent and inapparent cases) by 33.6-fold (range: 18.7- 53.6). Conclusion: Dengue incidence in Cambodia is increasing and disease is shifting to older pediatric populations. National surveillance continues to under-estimate case numbers. Future interventions should account for disease under-estimation and shifting demographics for scaling and to target appropriate age groups.

Consistency of recommendations of clinical practice guidelines in periodontology: a systematic review.

The aim of this systematic review was to evaluate the methodological quality and the consistency of recommendations of clinical practice guidelines (CPGs) in Periodontology. An electronic search was conducted in two databases, MEDLINE and EMBASE, eight CPGs databases, and home pages of scientific societies in Periodontology up to April 2022. Three reviewers independently assessed methodological quality using the AGREE II instrument. In addition, we evaluated the consistency of the recommendations. Eleven CPGs were included, and the topics developed focused on prevention, diagnosis, risk factors, surgical and non-surgical periodontal treatment, antimicrobial therapy, root coverage, and maintenance. We found that the AGREE domains 2 (Stakeholder involvement) and 5 (Applicability) obtained the lowest scores. Domains 1 (Scope and purpose), 3 (Rigor of development) and 4 (Clarity of presentation) obtained the highest scores among the evaluated CPGs. The clinical recommendations for treatment of periodontal diseases were mostly consistent. Overall, the quality of CPGs used in periodontics was high. There was consistency of recommendations in specific fields. These findings may help researchers to promote CPGs focused on different fields of periodontics that have not yet been developed. Furthermore, the clinician will be able to make better clinical decisions.

Consistency of recommendations of clinical practice guidelines in periodontology: a systematic review

Abstract The aim of this systematic review was to evaluate the methodological quality and the consistency of recommendations of clinical practice guidelines (CPGs) in Periodontology. An electronic search was conducted in two databases, MEDLINE and EMBASE, eight CPGs databases, and home pages of scientific societies in Periodontology up to April 2022. Three reviewers independently assessed methodological quality using the AGREE II instrument. In addition, we evaluated the consistency of the recommendations. Eleven CPGs were included, and the topics developed focused on prevention, diagnosis, risk factors, surgical and non-surgical periodontal treatment, antimicrobial therapy, root coverage, and maintenance. We found that the AGREE domains 2 (Stakeholder involvement) and 5 (Applicability) obtained the lowest scores. Domains 1 (Scope and purpose), 3 (Rigor of development) and 4 (Clarity of presentation) obtained the highest scores among the evaluated CPGs. The clinical recommendations for treatment of periodontal diseases were mostly consistent. Overall, the quality of CPGs used in periodontics was high. There was consistency of recommendations in specific fields. These findings may help researchers to promote CPGs focused on different fields of periodontics that have not yet been developed. Furthermore, the clinician will be able to make better clinical decisions.

Factores de riesgo relacionados con la depresión postparto / Risk factors related to postpartum depression / Fatores de risco relacionados à depressão pós-parto

El puerperio se considera una de las etapas más importantes del término del embarazo que atraviesan el cuerpo de la una mujer, donde puede ocasionar un estado de fragilidad psicológica, con la presentación de trastornos psiquiátricos, que puede aparecer de forma leve a grave en todas las mujeres posterior al parto, y hasta un año del mismo, se caracteriza por tener efectos a corto, mediano y largo plazo, en la madre, en el recién nacido y en la familia. El objetivo del presente estudio fue analizar los factores de riesgo de mayor impacto y relevancia en la depresión postparto en Ecuador. Se realizó una revisión bibliográfica narrativa de la literatura científica, de factores de riesgo relacionados a depresión postparto. Se concluyó que la depresión en la etapa postparto ha ido en aumento en los últimos años, al igual que los factores de riesgo de mayor prevalencia, destacando; el estado civil, nivel socio económico, y antecedentes de depresión previos. Los presentes hallazgos ponen de manifiesto la magnitud del problema de la depresión postparto, así como la relevancia de continuar con esta línea de investigación, formular y proponer estrategias de prevención frente a los principales factores de riesgos mencionados con anterioridad.

The puerperium is considered one of the most important stages of the term of pregnancy that a woman's body goes through, where it can cause a state of psychological fragility, with the presentation of psychiatric disorders, which can appear from mild to severe in all women after childbirth, and up to a year of it, is characterized by having short, medium and long-term effects on the mother, the newborn and the family. The objective of this study was to analyze the risk factors with the greatest impact and relevance in postpartum depression in Ecuador. A narrative bibliographic review of the scientific literature on risk factors related to postpartum depression was carried out. It was concluded that depression in the postpartum stage has been increasing in recent years, as well as the most prevalent risk factors, highlighting; marital status, socioeconomic status, and previous history of depression. These findings highlight the magnitude of the problem of postpartum depression, as well as the relevance of continuing with this line of research, formulating and proposing prevention strategies against the main risk factors mentioned above.

O puerpério é considerado uma das fases mais importantes do termo gestacional por que passa o corpo da mulher, onde pode causar um estado de fragilidade psicológica, com a apresentação de transtornos psiquiátricos, que podem se apresentar de leve a grave em todas as mulheres após parto, e até um ano dele, caracteriza-se por ter efeitos a curto, médio e longo prazo sobre a mãe, o recém-nascido e a família. O objetivo deste estudo foi analisar os fatores de risco com maior impacto e relevância na depressão pós-parto no Equador. Foi realizada uma revisão bibliográfica narrativa da literatura científica sobre fatores de risco relacionados à depressão pós-parto. Concluiu-se que a depressão na fase puerperal vem aumentando nos últimos anos, assim como os fatores de risco mais prevalentes, destacando; estado civil, situação socioeconômica e história prévia de depressão. Esses achados destacam a magnitude do problema da depressão pós-parto, bem como a relevância de continuar com essa linha de pesquisa, formulando e propondo estratégias de prevenção contra os principais fatores de risco citados acima.

Evaluation of cutaneous immune response in a controlled human in vivo model of mosquito bites.

Mosquito-borne viruses are a growing global threat. Initial viral inoculation occurs in the skin via the mosquito 'bite', eliciting immune responses that shape the establishment of infection and pathogenesis. Here we assess the cutaneous innate and adaptive immune responses to controlled Aedes aegypti feedings in humans living in Aedes-endemic areas. In this single-arm, cross-sectional interventional study (trial registration #NCT04350905), we enroll 30 healthy adult participants aged 18 to 45 years of age from Cambodia between October 2020 and January 2021. We perform 3-mm skin biopsies at baseline as well as 30 min, 4 h, and 48 h after a controlled feeding by uninfected Aedes aegypti mosquitos. The primary endpoints are measurement of changes in early and late innate responses in bitten vs unbitten skin by gene expression profiling, immunophenotyping, and cytokine profiling. The results reveal induction of neutrophil degranulation and recruitment of skin-resident dendritic cells and M2 macrophages. As the immune reaction progresses T cell priming and regulatory pathways are upregulated along with a shift to Th2-driven responses and CD8+ T cell activation. Stimulation of participants' bitten skin cells with Aedes aegypti salivary gland extract results in reduced pro-inflammatory cytokine production. These results identify key immune genes, cell types, and pathways in the human response to mosquito bites and can be leveraged to inform and develop novel therapeutics and vector-targeted vaccine candidates to interfere with vector-mediated disease.

Metagenomic Pathogen Sequencing in Resource-Scarce Settings: Lessons Learned and the Road Ahead.

Metagenomic next-generation sequencing (mNGS) is the process of sequencing all genetic material in a biological sample. The technique is growing in popularity with myriad applications including outbreak investigation, biosurveillance, and pathogen detection in clinical samples. However, mNGS programs are costly to build and maintain, and additional obstacles faced by low- and middle-income countries (LMICs) may further widen global inequities in mNGS capacity. Over the past two decades, several important infectious disease outbreaks have highlighted the importance of establishing widespread sequencing capacity to support rapid disease detection and containment at the source. Using lessons learned from the COVID-19 pandemic, LMICs can leverage current momentum to design and build sustainable mNGS programs, which would form part of a global surveillance network crucial to the elimination of infectious diseases.

Land tenure drives Brazil's deforestation rates across socio-environmental contexts.

Many tropical forestlands are experiencing changes in land-tenure regimes, but how these changes may affect deforestation rates remains ambiguous. Here, we use Brazil's land-tenure and deforestation data and quasi-experimental methods to analyze how six land-tenure regimes (undesignated/untitled, private, strictly-protected and sustainable-use protected areas, indigenous, and quilombola lands) affect deforestation across 49 spatiotemporal scales. We find that undesignated/untitled public regimes with poorly defined tenure rights increase deforestation relative to any alternative regime in most contexts. The privatization of these undesignated/untitled lands often reduces this deforestation, particularly when private regimes are subject to strict environmental regulations such as the Forest Code in Amazonia. However, private regimes decrease deforestation less effectively and less reliably than alternative well-defined regimes, and directly privatizing either conservation regimes or indigenous lands would most likely increase deforestation. This study informs the ongoing political debate around land privatization/protection in tropical landscapes and can be used to envisage policy aligned with sustainable development goals.

Púrpura de Schönlein Henoch en paciente adulto

RESUMEN La púrpura de Schönlein-Henoch es una vasculitis por fragmentación de leucocitos inmunomediada que afecta a pequeños vasos sanguíneos. Los cuatro componentes clínicos esenciales son púrpuras, dolor abdominal, artralgia y afectación renal. El caso trata de una mujer de 50 años que ingresa por dolor abdominal y hematoquecia de 72 horas de evolución, posterior a laparotomía exploratoria. Al examen físico presenta lesiones purpúricas en tronco y extremidades inferiores de 2 meses de aparición. En paraclínicos se observa hemograma con plaquetas normales, proteínas en orina 500 mg/dL, proteinuria 2,4 g/24 hs. Ante sospecha de vasculitis con plausible inclusión cutáneo-renal, se pide anticuerpos antinucleares, ANCA y se realiza biopsia cutánea evidenciándose una vasculitis neutrofílica necrotizante de pequeños vasos. En la biopsia renal se observa en inmunofluorescencia directa depósito de IgA, C3 positivo. En relación clínica de la proteinuria y compromiso cutáneo junto con la confirmación de biopsia renal se concluye en diagnóstico de púrpura de Schönlein Henoch. El interés de este caso radica en la inconsistencia de esta patología en los adultos, a pesar de que bien podría ser de una gravedad más notable dado que existe un mayor peligro de falla renal persistente.

ABSTRACT Schönlein-Henoch purpura is an immune-mediated leukocyte fragmentation vasculitis that affects small blood vessels. The four essential clinical components are purpura, abdominal pain, arthralgia, and renal involvement. This case concerns a 50-year-old woman who is admitted due to abdominal pain and hematochezia of 72 hours of evolution, after an exploratory laparotomy. On physical examination, she presents purpuric lesions on the trunk and lower extremities of 2 months of appearance. In paraclinical tests, a blood count with normal platelets, urine protein 500 mg/dL, and proteinuria 2.4 g/24 hours are observed. Suspecting vasculitis with plausible cutaneous-renal inclusion, antinuclear antibodies and ANCA are requested, and a skin biopsy is performed, showing necrotizing neutrophilic vasculitis of small vessels. In the renal biopsy, IgA deposit, C3 positive is observed in the direct immunofluorescence. In the clinical relationship of proteinuria and skin involvement together with the confirmation of renal biopsy, the diagnosis of Schönlein-Henoch purpura is concluded. The interest of this case lies in the inconsistency of this pathology in adults, despite the fact that it could be more serious given that there is a greater risk of persistent renal failure.

Gas in scattering media absorption spectroscopy as a potential tool in neonatal respiratory care.

Gas in scattering media absorption spectroscopy (GASMAS) is a novel optical technology employing near-infrared light. It has a potential use in the medical setting as a monitoring and diagnostic tool by detecting molecular oxygen within gas pockets and thus may be a useful adjunct in respiratory monitoring. GASMAS has potential advantages over other monitoring devices currently used in clinical practice. It is a non-invasive, continuous, non-ionising technology and provides unique information about molecular oxygen content inside the lungs. GASMAS may have a future role in optimising respiratory management of neonates in different clinical scenarios such as monitoring cardiorespiratory transition in the delivery room, assessing surfactant deficiency, and optimising endotracheal tube positioning. This article aims to summarise current evidence exploring GASMAS application in a neonate, discuss possible clinical benefits, and compare with other devices that are currently used in neonatal care. IMPACT: This article presents a novel optical technique to measure lung oxygen concentrations that may have important clinical uses. This review summarises the current literature investigating the concept of optical lung oxygen measurement. Information from this review can guide researchers in future studies.

Numerical investigation of the influence of the source and detector position for optical measurement of lung volume and oxygen content in preterm infants.

There is an urgent need for improved respiratory surveillance of preterm infants. Gas in scattering media absorption spectroscopy (GASMAS) is emerging as a potential clinical cutaneous monitoring tool of lung functions in neonates. A challenge in the clinical translation of GASMAS is to obtain sufficiently high signal-to-noise ratios in the measurements, since the light attenuation is high in human tissue. Previous GASMAS studies on piglets have shown higher signal quality with an internal source, as more light propagates through the lung and the loss due to scattering and absorption is less. In this article we simulated light propagation with an intratracheal and a dermal source, and investigated the signal quality and lung volume probed. The results suggest that GASMAS has the potential to measure respiratory volumes; and the sensitivity is higher for an intratracheal source which also enables to probe most of the lung.

Lung tissue phantom mimicking pulmonary optical properties, relative humidity, and temperature: a tool to analyze the changes in oxygen gas absorption for different inflated volumes.

SIGNIFICANCE: Gas in scattering media absorption spectroscopy (GASMAS) enables noninvasive gas sensing in the body. It is developing as a tool for diagnosis and monitoring of respiratory conditions in neonates. Phantom models with relevant features to the clinical translation of GASMAS technology are necessary to understand technical challenges and potential applications of this technique. State-of-the-art phantoms designed for this purpose have focused on the optical properties and anthropomorphic geometry of the thorax, contributing to the source-detector placement, design, and optimization. Lung phantom mimicking the alveolar anatomy has not been included in the existent models due to the inherent complexity of the tissue. We present a simplified model that recreates inflated alveoli embedded in lung phantom. AIM: The goal of this study was to build a lung model with air-filled structures mimicking inflated alveoli surrounded by optical phantom with accurate optical properties (µa = 0.50 cm - 1 and µs'=5.4 cm-1) and physiological parameters [37°C and 100% relative humidity (RH)], and to control the air volume within the phantom to demonstrate the feasibility of GASMAS in sensing changes in pulmonary air volume. APPROACH: The lung model was built using a capillary structure with analogous size to alveolar units. Part of the capillaries were filled with liquid lung optical phantom to recreate scattering and absorption, whereas empty capillaries mimicked air filled alveoli. The capillary array was placed inside a custom-made chamber that maintained pulmonary temperature and RH. The geometry of the chamber permitted the placement of the laser head and detector of a GASMAS bench top system (MicroLab Dual O2 / H2O), to test the changes in volume of the lung model in transmittance geometry. RESULTS: The lung tissue model with air volume range from 6.89 × 10 - 7 m3 to 1.80 × 10 - 3 m3 was built. Two measurement sets, with 10 different capillary configurations each, were arranged to increase or decrease progressively (in steps of 3.93 × 10 - 8 m3) the air volume in the lung model. The respective GASMAS data acquisition was performed for both data sets. The maximum absorption signal was obtained for configurations with the highest number of air-filled capillaries and decreased progressively when the air spaces were replaced by capillaries filled with liquid optical phantom. Further studies are necessary to define the minimum and maximum volume of air that can be measured with GASMAS-based devices for different source-detector geometries. CONCLUSIONS: The optical properties and the structure of tissue from the respiratory zone have been modeled using a simplified capillary array immersed in a controlled environment chamber at pulmonary temperature and RH. The feasibility of measuring volume changes with GASMAS technique has been proven, stating a new possible application of GASMAS technology in respiratory treatment and diagnostics.

Longitudinal Outcomes of a Smartphone Application to Prevent Drug Use Among Hispanic Youth.

OBJECTIVE: This trial tested the efficacy of a smartphone application (app) designed to prevent drug use among Hispanic youth. METHOD: Participants were recruited through online advertising and youth service agencies. The baseline sample (N = 644) had a mean age of 14.1 years, was primarily female (60%), and resided in 31 U.S. states and Puerto Rico. Youth assented to study participation and received parental permission to participate. Youth were randomly assigned to an intervention arm or a measurement-only control arm. Intervention-arm youth completed 10 prevention program sessions via a smartphone app. Following intervention delivery, all youth completed posttest and 1-, 2-, and 3-year follow-up measures. RESULTS: Analyzed within an Arm by Time interaction model, follow-up data showed that compared with control-arm youth, intervention-arm youth reported (a) less increase in alcohol use from baseline to 2-year follow-up; (b) less increase in marijuana use from baseline to 2- and 3-year follow-ups; and (c) less increase in polydrug use from baseline to 1-, 2-, and 3-year follow-ups. Compared with youth in the control arm, intervention-arm youth reported (a) less depressed mood and improved skills for refusing offers of alcohol and tobacco at posttest; (b) higher self-efficacy and social self-efficacy at 1-, 2-, and 3-year follow-ups; (c) improved skills for refusing offers of marijuana at 2- and 3-year follow-ups; (d) higher media literacy at 2- and 3-year follow-ups; and (e) better coping skills at 3-year follow-up. CONCLUSIONS: These longitudinal findings suggest that Hispanic youth can profit from tailored, skills-based content delivered via a smartphone app to prevent drug use.