Rate and predictors of insufficient sweat volume in very young infants after pilocarpine gel iontophoresis: prospective, population-based study.

OBJECTIVE: To verify the rate and predictors of 'quantity not sufficient' (QNS) among Brazilian infants younger than 3 months with positive newborn screening (NBS) for cystic fibrosis (CF). DESIGN: Prospective, population-based study. SETTING: Public Statewide Newborn Screening Programme where the incidence rate of CF is ≈1:11 000. PATIENTS: Subjects with positive two-tiered immunoreactive trypsinogen. INTERVENTIONS: Sweat induction and collection were performed in the same facility; one sweat sample was obtained per individual. MAIN OUTCOME MEASURES: The QNS rate and its predictors; analysis corresponded to the day of sweat collection. RESULTS: Among the 975 participants, QNS rates for 10 and 15 µL were 3.6% (95% CI 2.5% to 4.9%) and 8.3% (95% CI 6.6% to 10.2%). Infants weighing >3056 and >3845 g and with gestational age higher than 37 weeks had a greater likelihood (5.5 and 6.7, and 2.7 and 5.8 times more, respectively) of avoiding QNS than their peers. CONCLUSION: QNS rates fulfilled the requirements, but predictors differed from those recommended by the Cystic Fibrosis Foundations guidelines.

Sweat Rate, Sweat Sodium Losses, and Body Composition in Professional Male Soccer Players in Southwest Colombia.

Background and Objective: Dehydration and hyperhydration impact athletes' performance. Exploring the fluid balance concerning body composition might help estimate individual hydration requirements. This area of research, particularly regarding sodium losses, has been relatively understudied. We evaluated the sweat rate (SR), sweat sodium losses, and their relationship with body composition in professional soccer players in Cali, Colombia. Materials and Methods: Thirty-two male players, aged 24.3 (±5.2) years, from the Colombian main soccer league, underwent high-intensity training at 32 °C (with a relative humidity of 79%). The outcome variables included SR, calculated using weight loss and fluid intake; forearm sweat sodium concentration (FSCC), measured through the direct ion-selective electrode method; and estimated the predicted whole sweat sodium loss (PWSSL) in mmol. Predictor variables (body mass, fat, and muscle masses) were estimated using the Deborah Kerr anthropometry method. The association between predictors and outcomes was assessed using linear regression. Results: The mean FSCC, PWSSL, and SR were 26.7 ± 11.3 mmol/L, 43 ± 15.9 mmol/L, and 1.7 ± 0.5 L/h, respectively. Body mass positively predicted FSCC in unadjusted and age/fat-mass-adjusted models [Beta 1.28, 95% confidence interval (CI) 0.39-2.18, p = 0.006], and continued related to FSCC after adjustment for muscle mass with marginal significance [Beta 0.85, 95% CI -0.02 to 1.73, p = 0.056]. Muscle mass was associated with the PWSSL in unadjusted and age/fat-mass-adjusted models [Beta 2.42, 95% CI 0.58-4.26, p = 0.012] and sustained an association with marginal statistical significance after adjustment for body mass [Beta 1.86, 95% CI -0.35 to 4.09, p = 0.097]. Conclusions: Under hot tropical weather conditions, FSCC was relatively low among the players. Body mass was better associated with the FSSC, and muscle mass better related to the PWSSL. Body and muscle masses could be regarded as potential factors to be explored in the estimation of individual sodium needs. However, further studies are required to validate and contrast our findings.

Capillary electrophoresis with capacitively coupled contactless conductivity detection (C4 D) for rapid and simple determination of lactate in sweat.

An analytical method based on capillary electrophoresis (CE) using capacitively coupled contactless conductivity detection (C4 D) was developed and validated for fast, straightforward, and reliable determination of lactate in artificial and human sweat samples. The background electrolyte was composed of equimolar concentrations (10 mmol/L) of 2-(N-morpholino)ethanesulfonic acid and histidine, with 0.2 mmol/L of cetyltrimethylammonium bromide as electroosmotic flow inverter. The limit of detection and quantification were 3.1 and 10.3 µmol/L, respectively. Recoveries in the 97 to 118% range were obtained using sweat samples spiked with lactate at three concentration levels, indicating an acceptable accuracy. The intraday and interday precisions were 1.49 and 7.08%, respectively. The proposed CE-C4 D method can be a starting point for monitoring lactate concentrations in sweat samples for diagnostics, physiological studies, and sports performance assessment applications.

Sweat conductivity diagnostic accuracy for cystic fibrosis: a systematic review and meta-analysis.

OBJECTIVE: We conducted a systematic review and meta-analysis of diagnostic test accuracy studies to summarise the properties of sweat conductivity (SC) to rule in/out cystic fibrosis (CF). DATA SOURCE: We searched PubMed, Embase, Web of Science, Google Scholar, SciELO and LILACS up to 13 March 2023. STUDY SELECTION: We selected prospective and retrospective diagnostic test accuracy studies which compared SC, measured through two well-established and commercially available devices, that is, Nanoduct or Sweat-Chek Analyser, to quantitative measurement of sweat chloride. MAIN OUTCOME MEASURES: Pooled sensitivity, specificity, positive likelihood ratio (+LR) and negative likelihood ratio (-LR), and their corresponding 95% CIs. DATA EXTRACTION AND SYNTHESIS: The Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies guidelines were followed. Data were extracted by one reviewer and checked by another. The hierarchical summary receiver operating characteristics model was used to estimate diagnostic test accuracy. RESULTS: Ten studies involving 8286 participants were included. The pooled estimates of sensitivity, specificity, +LR and -LR were 0.97 (95% CI 0.94 to 0.98), 0.99 (95% CI 0.98 to 0.99), 171 (95% CI 58 to 500) and 0.02 (95% CI 0.01 to 0.05), respectively. Sensitivity analyses did not reveal a substantial impact of study-level factors on the results, such as study quality, cut-off values for a positive test, study sample size and participant age group. The quality of evidence was considered moderate. CONCLUSION: SC demonstrated excellent diagnostic performance. In addition, its accuracy parameters suggest its role as an alternative to the sweat test for CF diagnosis. PROSPERO REGISTRATION NUMBER: CRD42022284504.

Sweat conductivity for diagnosing cystic fibrosis after positive newborn screening: prospective, diagnostic test accuracy study.

OBJECTIVE: To assess the accuracy of sweat conductivity among newborns and very young infants. DESIGN: Prospective, population-based, diagnostic test accuracy study. SETTING: Public Statewide Newborn Screening Programme where the incidence rate of cystic fibrosis (CF) is ≈1:11 000. PATIENTS: Newborns and very young infants with positive two-tiered immunoreactive trypsinogen. INTERVENTIONS: Sweat conductivity and sweat chloride were performed simultaneously, on the same day and facility by independent technicians, with the cut-off values of 80 mmol/L and 60 mmol/L, respectively. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values (PPV and NPV), overall accuracy, positive and negative likelihood ratios (+LR, -LR) and post (sweat conductivity (SC)) test probability were calculated to assess SC performance. RESULTS: 1193 participants were included, 68 with and 1108 without CF, and 17 with intermediate values. The mean (SD) age was 48 (19.2) days, ranging from 15 to 90 days. SC yielded sensitivity of 98.5% (95% CI 95.7 to 100), specificity of 99.9% (95% CI 99.7 to 100), PPV of 98.5% (95% CI 95.7 to 100) and NPV of 99.9% (95% CI 99.7 to 100), overall accuracy of 99.8% (95% CI 99.6 to 100), +LR of 1091.7 (95% CI 153.8 to 7744.9) and -LR of 0.01 (95% CI 0.00 to 0.10). After a positive and negative sweat conductivity result, the patient's probability of CF increases around 350 times and drops to virtually zero, respectively. CONCLUSION: Sweat conductivity had excellent accuracy in ruling in or ruling out CF after positive two-tiered immunoreactive trypsinogen among newborns and very young infants.

Analysis of Stimulants in Sweat and Urine Using Disposable Pipette Extraction and Gas Chromatography Coupled to Mass Spectrometry in the Context of Doping Control.

Urine is initially collected from athletes to screen for the presence of illicit drugs. Sweat is an alternative sample matrix that provides advantages over urine including reduced opportunity for sample adulteration, longer detection-time window and non-invasive collection. Sweat is suitable for analysis of the parent drug and metabolites. In this study, a method was developed and validated to determine the presence of 13 amphetamine- and cocaine-related substances and their metabolites in sweat and urine using disposable pipette extraction (DPX) by gas chromatography coupled to mass spectrometry. The DPX extraction was performed using 0.1 M HCl and dichloromethane:isopropanol:ammonium hydroxide (78:20:2, v/v/v) followed by derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide at 90°C for 20 min. DPX extraction efficiencies ranged between 65.0% and 96.0% in urine and 68.0% and 101.0% in sweat. Method accuracy was from 90.0% to 104.0% in urine and from 89.0% to 105.0% in sweat. Intra-assay precision in urine and in sweat were <15.6% and <17.8%, respectively, and inter-assay precision ranged from 4.70% to 15.3% in urine and from 4.05% to 15.4% in sweat. Calibration curves presented a correlation coefficient -0.99 for all analytes in both matrices. The validated method was applied to urine and sweat samples collected from 40 professional athletes who knowingly took one or more of the target illicit drugs. Thirteen of 40 athletes were positive for at least one drug. All the drugs detected in the urine were also detected in sweat samples indicating that sweat is a viable matrix for screening or confirmatory drug testing.

Independent association between hypoxemia and night sweats in obstructive sleep apnea.

PURPOSE: To assess the relationship between hypoxemia during polysomnography (PSG) and patient-reported night sweats (NS). METHODS: This retrospective observational study included adult patients who completed a standardized sleep questionnaire and the Epworth Sleepiness Scale (ESS) before PSG. RESULTS: We included 1397 patients (41% women). The median age was 52 years, 80% had obstructive sleep apnea (OSA) defined as an apnea-hypopnea index (AHI) ≥ 5, and 35% were obese. A total of 245 patients (17.5%) reported NS. Their prevalence was higher among patients with OSA compared to controls (18.9% vs. 12.2%, p < 0.01). In the bivariate analysis, the variables associated with NS were BMI, AHI, hypoxemia (T90 ≥ 2.5% of total recording time plus minimum SO2 < 85%), frequent body movements or awakenings, nightmares, excessive daytime sleepiness (Epworth > 10), nocturia, cardiovascular events, and the use of sedatives or antidepressants. In the multivariate model, the independent predictors of NS were BMI (OR: 1.47, CI 95%: 1.07-2.01, p = 0.016), hypoxemia (OR: 1.87, CI 95%: 1.37-2.60, p = 0.0001), nightmares (OR: 2.60, CI 95%: 1.73-3.80, p < 0.0001), frequent body movements and awakenings (OR: 1.57, CI 95%: 1.16-2.11, p = 0.003 and OR: 1.54, CI 95%: 1.13-2.08, p = 0.005, respectively), and excessive daytime sleepiness (OR: 1.65, CI 95%: 1.24-2.20, p = 0.0007). CONCLUSIONS: In patients with OSA, night sweats were significantly and independently associated with a higher hypoxic burden.

Ampliação de uso da dosagem de cloreto no suor para pacientes com fibrose cística a partir de seis anos / Expansion of the use of sweat chloride measurement for patients with cystic fibrosis from six years

INTRODUÇÃO: A Fibrose Cística (FC) é uma doença genética em que se observa desequilíbrio na concentração de cloro e sódio nas células que produzem assecreções do corpo, como muco e suor. Como resultado do acúmulo demuco e consequente proliferação de patógenos, observa-se como principaissintomas:tosse crônica, pneumonia de repetição, diarreia, pólipos nasais, e déficits de peso e estatura. O diagnóstico é feito a partir da sintomatologia apresentada, teste do suor e testagem genética. O novo PCDT de FC encontra-se em fase de atualização. Nele é preconizado o uso do ivacaftor para o tratamento da FC em pacientes com idade ≥ 6 anos e ≥25 kg que apresentam uma das seguintes mutações no gene CFTR: G551D, G1244E, G1349D, G178R, G551S, S1251N, S1255P, S549N, S549R, já incorporado no Sistema Único de Saúde (SUS). CONSIDERAÇÕES FINAIS: Considerando que o medicamento ivacaftor é preconizado para pacientes a partir de seis anos de idade, verifica-se que o procedimento atualmente disponível no SUS não possibilita o atendimento desta população, uma vez que a idade máxima permitida é de dois anos. Ressalta-se que aqueles pacientes que não apresentarem melhora nos níveis de cloro no suor após exposição ao ivacaftor não devem continuar recebendo o medicamento pela baixa chance de apresentarresposta clínica. Portanto, a realização do exame é fundamental para que haja o uso racional domedicamento. Como apresentado sua inclusão possui um baixo impacto financeiro no orçamento total. Dessa forma, entende-se como um procedimento necessário para o completo tratamento da FC aos pacientes atendidos no SUS. RECOMENDAÇÃO PRELIMINAR: Os membros do Plenário presentes na 111ª Reunião Ordinária da Conitec, realizada no dia 04 de agosto de 2022, sem nenhuma declaração de conflito de interesse, deliberaram por unanimidade, encaminhar o tema para consulta pública com recomendação preliminar favorável ampliação de uso da dosagem de cloreto no suor para pacientes com fibrose cística a partir de seis anos. CONSULTA PÚBLICA: Consulta Pública (CP) nº62/2022: Disponibilizada no período de 13 de setembro a 03 de outubro de 2022, recebeu 7 (sete) contribuições ao todo, sendo uma contribuição técnico-científica e 6(seis) contribuições sobre experiência ou opinião. Todas as contribuições se mostraram favoráveis a ampliação do procedimento. Não houve mais ponderações. Todos os presentes declararam não possuir conflitos de interesse. RECOMENDAÇÃO FINAL DA CONITEC: Os membros do plenário, presentes na 113ª Reunião Ordinária, realizada no dia 06 de outubro de 2022, deliberaram por unanimidade recomendar a ampliação de uso, no SUS, da dosagem de cloreto no suor para pacientes com fibrose cística a partir de seis anos. Assim, foi assinado o Registro de Deliberação nº 776/2022. DECISÃO: ampliar o uso, no âmbito do Sistema Único de Saúde - SUS, da dosagem de cloreto no suor para pacientes com fibrose cística a partir de seis anos, conforme a Portaria nº 146, publicada no Diário Oficial da União nº 214, seção1, página 93, em 11 de novembro de 2022.

Foxa1 mediates eccrine sweat gland development through transcriptional regulation of Na-K-ATPase expression.

Eccrine sweat glands (ESGs) perform critical functions in temperature regulation in humans. Foxa1 plays an important role in ESG maturation and sweat secretion. Its molecular mechanism, however, remains unknown. This study investigated the expression of Foxa1 and Na-K-ATPase (NKA) in rat footpads at different development stages using immunofluorescence staining, qRT-PCR, and immunoblotting. Also, bioinformatics analysis and Foxa1 overexpression and silencing were employed to evaluate Foxa1 regulation of NKA. The results demonstrated that Foxa1 was consistently expressed during the late stages of ESGs and had a significant role in secretory coil maturation during sweat secretion. Furthermore, the mRNA abundance and protein expression of NKA had similar accumulation trends to those of Foxa1, confirming their underlying connections. Bioinformatics analysis revealed that Foxa1 may interact with these two proteins via binding to conserved motifs in their promoter regions. Foxa1 gain-of-function and loss-of-function experiments in Foxa1-modified cells demonstrated that the activities of NKA were dependent on the presence of Foxa1. Collectively, these data provided evidence that Foxa1 may influence ESG development through transcriptional regulation of NKA expression.

Wearable electrochemical biosensors to measure biomarkers with complex blood-to-sweat partition such as proteins and hormones.

Smart electronic devices based on micro-controllers, also referred to as fashion electronics, have raised wearable technology. These devices may process physiological information to facilitate the wearer's immediate biofeedback in close contact with the body surface. Standard market wearable devices detect observable features as gestures or skin conductivity. In contrast, the technology based on electrochemical biosensors requires a biomarker in close contact with both a biorecognition element and an electrode surface, where electron transfer phenomena occur. The noninvasiveness is pivotal for wearable technology; thus, one of the most common target tissues for real-time monitoring is the skin. Noninvasive biosensors formats may not be available for all analytes, such as several proteins and hormones, especially when devices are installed cutaneously to measure in the sweat. Processes like cutaneous transcytosis, the paracellular cell-cell unions, or even reuptake highly regulate the solutes content of the sweat. This review discusses recent advances on wearable devices based on electrochemical biosensors for biomarkers with a complex blood-to-sweat partition like proteins and some hormones, considering the commented release regulation mechanisms to the sweat. It highlights the challenges of wearable epidermal biosensors (WEBs) design and the possible solutions. Finally, it charts the path of future developments in the WEBs arena in converging/emerging digital technologies.

Additively manufactured carbon/black-integrated polylactic acid 3Dprintedsensor for simultaneous quantification of uric acid and zinc in sweat.

For the first time the development of an electrochemical method for simultaneous quantification of Zn2+ and uric acid (UA) in sweat is described using an electrochemically treated 3D-printed working electrode. Sweat analysis can provide important information about metabolites that are valuable indicators of biological processes. Improved performance of the 3D-printed electrode was achieved after electrochemical treatment of its surface in an alkaline medium. This treatment promotes the PLA removal (insulating layer) and exposes carbon black (CB) conductive sites. The pH and the square-wave anodic stripping voltammetry technique were carefully adjusted to optimize the method. The peaks for Zn2+ and UA were well-defined at around - 1.1 V and + 0.45 V (vs. CB/PLA pseudo-reference), respectively, using the treated surface under optimized conditions. The calibration curve showed a linear range of 1 to 70 µg L-1 and 1 to 70 µmol L-1 for Zn2+ and UA, respectively. Relative standard deviation values were estimated as 4.8% (n = 10, 30 µg L-1) and 6.1% (n = 10, 30 µmol L-1) for Zn2+ and UA, respectively. The detection limits for Zn2+ and UA were 0.10 µg L-1 and 0.28 µmol L-1, respectively. Both species were determined simultaneously in real sweat samples, and the achieved recovery percentages were between 95 and 106% for Zn2+ and 82 and 108% for UA.

Catalytic effects of magnetic and conductive nanoparticles on immobilized glucose oxidase in skin sensors.

Wearable skin sensors is a promising technology for real-time health care monitoring. They are of particular interest for monitoring glucose in diabetic patients. The concentration of glucose in sweat can be more than two orders of magnitude lower than in blood. In consequence, the scientific and technological efforts are focused in developing new concepts to enhance the sensitivity, decrease the limit of detection (LOD) and reduce the response time (RT) of glucose skin sensors. This work explores the effect of adsorbed superparamagnetic magnetite nanoparticles (MNPs) and conductive nanoparticles (CNPs) on carbon nanotube substrates (CNTs) used to immobilize glucose oxidase enzyme in the working electrode of skin sensors. MNPs and CNPs are made of magnetite and gold, respectively. The performance of the sensors was tested in standard buffer solution, artificial sweat, fresh sweat and on the skin of a healthy volunteer during an exercise session. In the case of artificial sweat, the presence of MNPs accelerated the RT from 7 to 5 s at the expense of increasing the LOD from 0.017 to 0.022 mM with slight increase of the sensitivity from 4.90 to 5.09µAm M-1cm-2. The presence of CNPs greatly accelerated the RT from 7 to 2 s and lowered the LOD from 0.017 to 0.014 mM at the expense of a great diminution of the sensitivity from 4.90 to 4.09µAm M-1cm-2. These effects were explained mechanistically by analyzing the changes in the concentration of free oxygen and electrons promoted by MNPs and CNPs in the CNTs and its consequences on the the glucose oxidation process.

Deodorants and antiperspirants: identification of new strategies and perspectives to prevent and control malodor and sweat of the body.

Excessive sweating and body odors in many cultures can cause negative perceptions of an individual and in many cases is related to poor hygiene. Personal hygiene products have been developed with the intention of preventing these undesirable issues. The aim of this paper is to review the main active ingredients used in marketed deodorant and antiperspirant formulations as well as to identify new strategies and future methods to optimize such products and prevent malodor. PubMed and ScienceDirect databases were used to search for studies reporting the use of deodorants and antiperspirants, the compounds used in the formulations, their mechanisms of action and associated controversies, as well as new trends and approaches in the area. Even today, we are still using well-known and established actives such as triclosan and aluminum salts, and these are still the most used compounds in deodorants with bactericidal and antiperspirant properties. These substances have been on the market for more than 40 years, and still there are many questions concerning the safety of both actives. There is a general increased interest globally for lifestyles that focus on sustainability and more natural products such as plant sources and the use of, for example, essential oils. The research that focuses in the area of antiperspirants and deodorants is now more focused on studies of the armpit biochemistry and function and control of the microbiota present in this area. Other possible areas of interest are biotechnological solutions and finding new compounds that will interfere with the biochemistry of the process of sweat decomposition. Further approaches include formulations with probiotics which would maintain the balance of axillary microbiota.

Zika virus RNA excretion in sweat with concomitant detection in other body fluid specimens.

We evaluated sweat, blood and urine specimens obtained from an ongoing cohort study in Brazil. Samples were collected at pre-established intervals after the initial rash presentation and tested for Zika virus (ZIKV) RNA presence by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 254 participants with confirmed infection, ZIKV RNA was detected in the sweat of 46 individuals (18.1%). Sweat presented a median cycle threshold (Ct) of 34.74 [interquartile range (IQR) 33.44-36.04], comparable to plasma (Ct 35.96 - IQR 33.29-36.69) and higher than urine (Ct 30.78 - IQR 28.72-33.22). Concomitant detection with other specimens was observed in 33 (72%) of 46 participants who had a positive result in sweat. These findings represent an unusual and not yet investigated virus shedding through eccrine glands.

A influência da idade e do genótipo sobre os níveis de cloreto do suor em uma população pediátrica com fibrose cística no estado da Bahia / The influence of age and genotype on sweat chloride levels in a pediatric population with cystic fibrosis in the state of Bahia

Introdução: a fibrose cística é a doença autossômica recessiva mais comum em populações caucasianas e a sua etiologia está associada a variantes patogênicas no gene CFTR. O teste do suor é considerado o padrão ouro para o diagnóstico dessa enfermidade. Estudos apontam que o genótipo do CFTR e a idade dos indivíduos influenciam as concentrações de cloreto no suor. Objetivos: pesquisar a correlação entre os níveis de cloreto no teste do suor e a idade ao diagnóstico de indivíduos com fibrose cística e comparar as concentrações iônicas do cloreto entre os sexos, diferentes faixas etárias e três grupos diversos de genótipos do CFTR. Metodologia: realizou-se um estudo de corte transversal, incluindo sujeitos de 0 a 20 anos, com diagnóstico confirmado de fibrose cística. Os indivíduos selecionados foram agrupados de acordo com as variáveis analisadas. Calcularam-se os valores descritivos das concentrações de íons cloreto de cada grupo. Utilizou-se o teste de Spearman para a análise da correlação entre a idade ao diagnóstico e os níveis de cloreto no suor. Resultados: 64 indivíduos foram incluídos no estudo, sendo 51,56% do sexo masculino. A mediana (Min ­ Max) da idade ao diagnóstico foi de 7 meses (1-206). Não foi observa da correlação entre a idade dos indivíduos ao diagnóstico e os níveis de cloreto no suor. As concentrações medianas de cloreto foram maiores nos escolares (106 mEq/l), no sexo feminino (102 mEq/l) e nos heterozigotos F508del/Classe I a III (108 mEq/l); e menores nos adolescentes (100 mEq/l) e nos heterozigotos F508del/Classes IV a VI (77 mEq/l). Conclusão: os níveis de cloreto no suor não apresentaram correlação com a idade dos indivíduos ao diagnóstico. A variação considerável dos níveis iônicos entre os grupos de diferentes genótipos corrobora que o teste do suor é um bom preditor da avaliação funcional do canal CFTR.

Introduction: cystic fibrosis is the most common autosomal recessive disorder in Caucasian populations and its etiology is associated with pathogenic variants in the CFTR gene. The sweat test is considered the gold standard for the diagnosis of the disease. Some studies suggest that CFTR genotype and age affect sweat chloride concentrations. Objectives: to investigate the correlation between sweat chloride levels and age at diagnosis of individuals with cystic fibrosis and to compare ionic chloride concentrations among sexes, different age groups and three distinct groups of CFTR genotypes. Methodology: a cross-sectional study was conducted, which included CF subjects from 0 to 20 years of age. The selected individuals were clustered on the variables in analysis. The description values for chloride ion concentrations in each group were calculated. The Spearman's test was used to analyze the correlation between the age at diagnosis and sweat chloride levels. Results: 64 individuals were included, 51,56% male. The median (Min ­ Max) age at diagnosis was 7 months (1-206). There was no correlation between the age at diagnosis and sweat chloride levels. The median of the chloride concentrations were higher for schoolchildren (106 mEq/l), females (102 mEq/l) and heterozygous F508del/Classes I to III (108 mEq/l), and reached the lowest values for teenagers (100 mEq/l) and heterozygous F508del/Classes IV to VI (77 mEq/l). Conclusion: sweat chloride levels did not correlate with the age of individuals at diagnosis. The substantial variation of ionic levels among groups of distinct genotypes corroborates that the sweat test is a good predictor for functional assessment of the CFTR channel.

Uric acid electrochemical sensing in biofluids based on Ni/Zn hydroxide nanocatalyst.

A highly sensitive sensor for quantification of uric acid (UA) directly in body fluids (saliva and sweat) is reported, working at a potential as low as 0.0 V vs Ag/AgCl. New mixed hydroxide materials exhibiting stable electrocatalytic responses from alkaline to acidic media were prepared, their structure was thoroughly characterized, and the electrochemical properties of the modified FTO (fluorine-doped tin oxide) electrodes were evaluated for UA determination by cyclic voltammetry, chronoamperometry, and batch injection analysis. A very low limit of detection (2.3 × 10-8 mol L-1) with good repeatability (RSD = 3.2% for 30 successive analyses) was achieved based on a fast and simple BIA procedure. Finally, α-Ni0.75Zn0.25(OH)2 screen-printed electrodes (SPE) were developed for the measurement of UA directly in real saliva and sweat samples, without interference of ascorbic acid, acetaminophen, lactate, and glucose at their typical concentrations present in those body fluids, revealing high potential for application as disposable sensors in biological systems. Graphical abstract.

Investigation of Ayahuasca ß-Carboline Alkaloids and Tryptamine in Sweat Samples from Religious Community Participants by GC-MS.

Ayahuasca, a hallucinogenic beverage used in religious rituals in South America, has become a global phenomenon. Its main active components are the ß-carbolines alkaloids, harmine (HRM) and harmaline (HRL), as well as the potent hallucinogen N,N-dimethyltryptamine (DMT). Despite its rising consumption, information regarding possible clinical applications and toxicological effects of ayahuasca is still limited. This study presents the first investigation of the use of sweat for the determination of DMT, HRM and HRL in ayahuasca users during a religious ritual. Sweat is an alternative matrix with advantages over many conventional biological samples, mainly because the collection procedure is non-invasive, easy and simple and samples can be collected without disturbing the religious ritual. In the study, solid-phase extraction was performed under basic conditions. Linearity was observed ranging from 20 to 1500 ng/patch with coefficients of determination (R2) higher than 0.99 for all analytes. The results indicated high selectivity for all investigated analytes, with extraction efficiency exceeding 70%, accuracy ranging from 87.5 to 102.4%, intra-assay precision of 1.85-9.44% and inter-assay precision between 3.34 and 9.85%. The limits of detection were 15 ng/patch for HRM and HRL and 10 ng/patch for DMT. The sweat proved to be a viable option to monitor ayahuasca use.

Investigation of sweat VOC profiles in assessment of cancer biomarkers using HS-GC-MS.

Volatile organic compounds (VOCs) have been studied in biological samples in order to be related to the presence of diseases. Sweat can represent substances existing in blood, has less complex composition (compared with other biological matrices) and can be obtained in a non-invasive way. In this work, sweat patches were collected from healthy controls and volunteers with cancer. Static Headspace was used for VOCs extraction, analysis was performed by gas chromatography coupled with mass spectrometry. Principal Components Analysis was used to investigate data distribution. Random Forest was employed to develop classificatory models. Controls and positive cases could be distinguished with maximum sensitivity and specificity (100% of accuracy) in a model based on the incidence of 2-ethyl-1-hexanol, hexanal and octanal. Discrimination between controls, primary tumors and metastasis was achieved using a panel with 11 VOCs. Balanced accuracy of more than 70% was obtained for the classification of a neoplasm site. Total n-aldehydes presented to be strongly correlated with staging of adenocarcinomas, while phenol and 2,6-dimethyl-7-octen-2-ol were correlated with Gleason score. These findings corroborate with the development of accessible screening tools based on VOC analysis and highlight sweat as a promising matrix to be studied in a clinical context for cancer diagnosis.