Decomposing the Mutual Information Rate of Heart Period and Respiration Variability Series to Assess Cardiorespiratory Interactions.

Heart rate variability results from the coupled activity of the cardiovascular and cardiorespiratory systems, which have their own internal regulation mechanisms but also interact with each other and with the autonomic nervous system to maintain homeostasis. In this work, the assessment of these physiological mechanisms is carried out decomposing the Mutual Information Rate (MIR), an information-theoretic measure of the interdependence between coupled processes, into terms of entropy rate or conditional mutual information related respectively to complexity and causality measures. These measures are computed using a non-parametric approach based on nearest-neighbors. The proposed framework is first tested on simulated autoregressive processes and then applied to experimental data consisting of heart period and respiratory time series measured in healthy subjects monitored at rest and during head-up tilt. Our results evidence that MIR decomposition is able to highlight the interdependence of short-term physiological mechanisms of cardiorespiratory interactions during postural stress.

Testing phylogenetic signal with categorical traits and tree uncertainty.

SUMMARY: The phylogenetic signal, frequently used to identify signatures of adaptive evolution or important associations between genes and phenotypes, measures the tendency for recently diverged species to resemble each other more than distantly related species. An example of such a measure is the δ statistic, which uses Shannon entropy to measure the degree of phylogenetic signal between a categorical trait and a phylogeny. In this study, we refined this statistic to account for tree uncertainty, resulting in more accurate assessments of phylogenetic associations. In addition, we provided a more accessible and computationally efficient implementation of the δ statistic that will facilitate its use by the evolutionary community. AVAILABILITY AND IMPLEMENTATION: github.com/diogo-s-ribeiro/delta-statistic.

Should the Preference-Based Index Set of Values Be Country or Disease Specific? An Analysis Using Data From Women With Symptoms of Overactive Bladder.

OBJECTIVES: Overactive bladder (OAB) and urinary incontinence (UI) are common conditions among women. We aimed to verify the difference between the preference-based index extracted from short-form six-dimension version one (SF-6Dv1) in women with OAB using different country-specific value sets, translate and cross-culturally adapt the King's Health Questionnaire Five Dimension (KHQ-5D) into Brazilian Portuguese, and examine the association between preference-based index obtained by the SF-6Dv1 and KHQ-5D. METHODS: This cross-sectional study included 387 women with OAB, divided into groups with and without UI. The participants answered the sociodemographic questionnaire, KHQ, KHQ-5D, and SF-6Dv1. A two-way mixed analysis of variance, with post hoc to multiple comparisons were applied and a Spearman's test was applied to verify the correlation between the preference-based index of SF-6Dv1 and KHQ-5D. RESULTS: The main analysis showed a statistically significant interaction between the presence of UI and the value set obtained from the different countries (P = .005, Cohen's d = 0.02). The post hoc analyses showed that there was a statistically significant main effect of the value sets obtained from different countries (P < .001, d = 0.63) and in the presence of UI (P = .012, d = 0.02). The correlations between the preference-based index obtained from different countries using the SF-6Dv1 and KHQ-5D were significant. CONCLUSIONS: Differences were observed between the preference-based index obtained in different countries and presence of UI, although positive and significant results were observed in the correlation between preference-based index from different countries. The correlation between general and specifics preference-based index was small; the SF-6Dv1 could be used in cost-utility studies for this population.

Optimization of Extraction Method of Anthocyanins from Red Cabbage.

Among the vegetables that stand out for their high concentration of anthocyanins, red cabbage appears as one of the most-used sources of these pigments in food production and it is considered a suitable raw material for the extraction of natural dye. Therefore, the objective was to carry out the production of natural extracts from red cabbage, under different conditions, varying the solvent, type of pre-treatment, pH range, and processing temperature during the concentration of the extracts. The anthocyanins were extracted from red cabbage using the following solvents: distilled water, 25% ethyl alcohol, and 70% ethyl alcohol. The raw material was divided into two groups, the first was subjected to a drying pre-treatment at 70 °C for 1 h and for the second group, the extraction was performed with the raw material in natura. Two pH ranges of 4.0 and 6.0 and extraction temperatures of 25 °C and 75 °C were used in the extracts, resulting in 24 formulations. The extracts obtained were analyzed for colorimetric parameters and anthocyanins. The results of anthocyanins show that the methodology that uses 25% alcohol, pH 4.0, and processing temperature of 25 °C produces a reddish extract and better results in the extraction, presenting average values of 191.37 mg/100 g of anthocyanins, being 74% higher compared to the highest values obtained in the other extracts where the same raw material was used and the solvents differed.

Evolution of the occurrence of Tityus serrulatus (LUTZ & MELLO, 1992) in the state of Santa Catarina.

BACKGROUND: Scorpions are a leading cause of envenomation in Brazil. The species Tityus serrulatus is associated with the most severe cases, especially in children. Despite not being endemic to the state of Santa Catarina, such occurrences have increased more than 500% in the state recently. Therefore, this study aimed to analyze the occurrence of envenomation by T. serrulatus, attended by the Center for Toxicological Information and Assistance of Santa Catarina. METHODS: This was a retrospective and descriptive study of the occurrence of T. serrulatus, identified by the agency, from 2014 to 2021 in Santa Catarina, using data obtained by the BI-DATATOX system. RESULTS: A total of 112 occurrences were classified as envenomation. Of these cases, 48.2% were recorded in the Itajaí Valley region and 33% in Greater Florianópolis. Men were involved in 59.8% of these, and the most common age group was 20-39 years (39.3%). Most envenomation occurred in urban areas (89.3%) under non-occupational circumstances (83%). Stings were more frequent on the hands (50.9%). Care was sought within 1 h after the event in 75.9% of the cases, and 94.6% were classified as mild. CONCLUSIONS: Occurrence of envenomation involving T. serrulatus in Santa Catarina increased significantly during the study period. Most cases occurred in urbanized areas, which suggests that they might have been transported from other states, and it must be considered that, in the urban environment, scorpions find a large supply of food and shelter and a reduced number of specific predators, allied to parthenogenesis.

Pelvic floor dysfunctions in women with fibromyalgia: A cross-sectional study.

BACKGROUND: Fibromyalgia (FM) is a rheumatic syndrome that causes musculoskeletal disorders and is associated with several problems that affect quality of life. As the musculoskeletal system is affected, it can have an impact on the pelvic floor muscles, leading to pelvic floor dysfunction (PFD). OBJECTIVE: Investigate the occurrence of PFD, such as urinary incontinence (UI) and anal incontinence (AI), sexual problems, and pelvic organ prolapse (POP), in women with FM compared to a control group composed of women without FM; and investigate the association between FM and PFD. STUDY DESIGN: This was an online cross-sectional survey. Demographic and anthropometric data, the description of PFD (UI, nocturia, AI, genital-pelvic pain/penetration disorder, and POP), and previous obstetric history were collected through a web-based questionnaire. The groups were compared using the independent t-test for quantitative variables and the chi-square test for categorical variables. The association between FM and PFD was tested using logistic regression analysis. RESULTS: A total of 175 women answered the questionnaire (97 with FM and 78 healthy controls). The women with FM reported significantly more UI, mixed urinary incontinence, AI, POP, and vaginismus than the healthy controls (p ≤ 0.05). FM was associated with mixed urinary incontinence (OR: 2.6; 95 % CI: 1.1-6.4; p = 0.04), anal incontinence (OR: 2.9; 95 % CI: 1.3-6.1; p = 0.01), and flatus incontinence (OR: 2.6; 95 % CI: 1.2-5.4; p = 0.01). CONCLUSION: The prevalence of PFD was significantly higher in women with FM compared to healthy women. Indeed, the women with FM were 2.6-fold to 2.9-fold more likely to report mixed urinary incontinence, anal and flatus incontinence than those in the control group. The present findings show possible impairment of the pelvic floor musculature in women with FM.

Pelvic floor dysfunctions in women with systemic lupus erythematosus: A cross-sectional study.

INTRODUCTION AND HYPOTHESIS: As a result of the impairment of the musculoskeletal system, the pelvic floor muscles are likely compromised in women with systemic lupus erythematosus (SLE). We hypothesized that women with SLE would report more symptoms of pelvic floor dysfunction (PFD) and there will be an association between SLE and PFD. METHODS: An online cross-sectional survey was conducted. Data were collected on demographic and anthropometric characteristics, PFD (urinary incontinence, nocturia, anal incontinence, genital-pelvic pain/penetration disorder and pelvic organ prolapse) and obstetric history using a web-based questionnaire. The groups were compared using the Mann-Whitney test for quantitative variables and the chi-squared test for categorical variables. The association between SLE and PFD was tested using logistic regression analysis. RESULTS: A total of 196 women answered the questionnaire (102 with SLE and 94 healthy controls). Women with SLE reported significantly more urinary incontinence, nocturia, anal incontinence, pelvic organ prolapse and genital-pelvic pain/penetration disorder than the healthy controls (p ≤ 0.05). Women with SLE were 2.8- to 3.0-fold more likely to report genital-pelvic pain/penetration disorder than healthy women. CONCLUSIONS: The prevalence of PFD was significantly higher in women with SLE compared to healthy women. Thus, PFD seems to be an important problem in women with this disease. An in-depth investigation of these disorders could contribute to the understanding of how SLE impacts pelvic floor function.

Evolution of the occurrence of Tityus serrulatus (LUTZ & MELLO, 1992) in the state of Santa Catarina

ABSTRACT Background: Scorpions are a leading cause of envenomation in Brazil. The species Tityus serrulatus is associated with the most severe cases, especially in children. Despite not being endemic to the state of Santa Catarina, such occurrences have increased more than 500% in the state recently. Therefore, this study aimed to analyze the occurrence of envenomation by T. serrulatus, attended by the Center for Toxicological Information and Assistance of Santa Catarina. Methods: This was a retrospective and descriptive study of the occurrence of T. serrulatus, identified by the agency, from 2014 to 2021 in Santa Catarina, using data obtained by the BI-DATATOX system. Results: A total of 112 occurrences were classified as envenomation. Of these cases, 48.2% were recorded in the Itajaí Valley region and 33% in Greater Florianópolis. Men were involved in 59.8% of these, and the most common age group was 20-39 years (39.3%). Most envenomation occurred in urban areas (89.3%) under non-occupational circumstances (83%). Stings were more frequent on the hands (50.9%). Care was sought within 1 h after the event in 75.9% of the cases, and 94.6% were classified as mild. Conclusions: Occurrence of envenomation involving T. serrulatus in Santa Catarina increased significantly during the study period. Most cases occurred in urbanized areas, which suggests that they might have been transported from other states, and it must be considered that, in the urban environment, scorpions find a large supply of food and shelter and a reduced number of specific predators, allied to parthenogenesis.

Multiscale Information Decomposition of Long Memory Processes: Application to Plateau Waves of Intracranial Pressure.

Traumatic Brain Injury (TBI) patients present high levels of physical stress, which in some situations can manifest as Plateau Wave (PW) episodes. This intense stress phenomenon can be evidenced by Heart Rate Variability (HRV). Thus, the multivariate and simultaneous analysis of cardio-cerebrovascular oscillations, involving the RR intervals, mean arterial pressure (MAP) and the amplitude of intracranial pressure (AMP), will be useful to understand the interconnections between body signals, allowing the interpretation of the combined activity of pathophysiological mechanisms. In this work, the multiscale representation of the Transfer Entropy (TE) and of its decomposition in the network of these three interacting processes is obtained, based on a Vector AutoRegressive Fractionally Integrated (VARFI) framework for Gaussian processes. This method allows to assess directed interactions and to quantify the information flow accounting for the simultaneous presence of short-term dynamics and long-range correlations. The results show that the baseline RR, but not MAP can provide information about the possibility of a PW arising. During PW, the long-term correlations highlight synergistic interactions between MAP and AMP processes on RR. The multiscale decomposition of the information along with the incorporation of the long term correlations allowed a better description of HRV during PW, highlighting the fact that the HRV mirrors this cerebrovascular phenomena.

Multiscale partial information decomposition of dynamic processes with short and long-range correlations: theory and application to cardiovascular control.

Objective.In this work, an analytical framework for the multiscale analysis of multivariate Gaussian processes is presented, whereby the computation of Partial Information Decomposition measures is achieved accounting for the simultaneous presence of short-term dynamics and long-range correlations.Approach.We consider physiological time series mapping the activity of the cardiac, vascular and respiratory systems in the field of Network Physiology. In this context, the multiscale representation of transfer entropy within the network of interactions among Systolic arterial pressure (S), respiration (R) and heart period (H), as well as the decomposition into unique, redundant and synergistic contributions, is obtained using a Vector AutoRegressive Fractionally Integrated (VARFI) framework for Gaussian processes. This novel approach allows to quantify the directed information flow accounting for the simultaneous presence of short-term dynamics and long-range correlations among the analyzed processes. Additionally, it provides analytical expressions for the computation of the information measures, by exploiting the theory of state space models. The approach is first illustrated in simulated VARFI processes and then applied to H, S and R time series measured in healthy subjects monitored at rest and during mental and postural stress.Main Results.We demonstrate the ability of the VARFI modeling approach to account for the coexistence of short-term and long-range correlations in the study of multivariate processes. Physiologically, we show that postural stress induces larger redundant and synergistic effects from S and R to H at short time scales, while mental stress induces larger information transfer from S to H at longer time scales, thus evidencing the different nature of the two stressors.Significance.The proposed methodology allows to extract useful information about the dependence of the information transfer on the balance between short-term and long-range correlations in coupled dynamical systems, which cannot be observed using standard methods that do not consider long-range correlations.

Production and Shelf-Life Study of Probiotic Caja (Spondias mombin L.) Pulp Using Bifidobacterium animalis ssp. Lactis B94.

The highly nutritional caja fruit (Spondias mombin L.) is an accessible source of vitamins and antioxidants that are indispensable for the human diet. The objective of the present work was to study the production of a probiotic caja pulp using Bifidobacterium animalis ssp. lactis B94. Firstly, a kinetic study was performed on the fermentation of the caja pulp with Bifidobacterium animalis ssp. lactis B94 to determine the optimum conditions of the process. Growth kinetics revealed that the ideal time for ending the fermentation would be at 22 h because it corresponds to the end of the exponential phase. Both the whole pulp and the probiotic pulp were characterized for pH, acidity, total soluble solids, water content, phenolic content, reducing carbohydrates, ascorbic acid, and total carotenoids. Physicochemical characterization revealed similar results between the whole and the probiotic pulp. The stability test demonstrated that the probiotic pulp is stable and preserved the probiotic attributes of the final product. In conclusion, our results reveal that caja pulp can be considered a favorable medium for the Bifidobacterium animalis ssp. lactis B94 growth and consequently can be explored biotechnologically for new food products.

Brazilian version of the King's Health Questionnaire: assessment of the structural validity and internal consistency in female urinary incontinence.

INTRODUCTION AND HYPOTHESIS: The use of valid patient-reported outcome measurements is essential in clinical and research settings. The structure of the Brazilian version of the King's Health Questionnaire (Br-KHQ) has not been evaluated. Thus, this study sought to evaluate the structural validity and internal consistency of the multi-item domains of the Br-KHQ in women with urinary incontinence (UI). METHODS: A total of 462 Brazilian Portuguese speakers with UI aged 18 years or older were included in this study. Participants answered the Br-KHQ, and a questionnaire containing demographic and personal information. The structure of the Br-KHQ was examined through Exploratory Factor Analysis (EFA) with the implementation of parallel analysis and evaluated using confirmatory factor analysis (CFA). For the latter, several goodness-of-fit indices were considered to evaluate the model fit of the structures tested in this study. Internal consistency was assessed using Cronbach's alpha, composite reliability, and coefficient omega. RESULTS: The EFA showed that the questionnaire has a five-factor structure, i.e., limitations of daily life, personal relationship, emotions, sleep/energy, and severity measures. The CFA demonstrated that this structure presented the most adequate goodness-of-fit indices and the lowest values of Akaike information criterion and Bayesian information criterion, compared with the original and Portuguese structure. High values (>0.70) of internal consistency were found. CONCLUSIONS: The Brazilian version of the KHQ is composed of a five-factor structure. Further studies should evaluate other measurement properties of the Br-KHQ to ensure reliable interpretation of this patient-reported outcome measure in clinical practice.

Are seizures associated with neuroschistosomiasis mansoni? An exploratory survey in an endemic area of Brazil.

BACKGROUND: Deposition of Schistosoma mansoni eggs in the brain of patients with hepatosplenic schistosomiasis (HS-SM) is frequent and usually asymptomatic. However, it is questioned whether it could cause seizures. Thus, we investigated the occurrence of seizures in these patients and also searched for parameters associated with this disorder. METHODS: In a cross-sectional survey, we compared 128 patients with HS-SM with 102 patients with portal hypertension due to compensated chronic hepatic disease of other etiologies. A standardized questionnaire, emphasizing epilepsy-related parameters, was applied to all participants. RESULTS: Eight (6.3%) patients with HS-SM had a history of seizures, whereas this condition was reported by three (2.9%) individuals from the comparison group (p=0.354). None of the variables were associated with the occurrence of seizures, either in univariate or in multivariate analysis. CONCLUSIONS: The frequency of seizures was similar in both study groups. However, it was higher than that described in population-based studies. Thus, we hypothesize that HS-SM individuals may have a higher frequency of seizure. The lack of difference between the two study groups may be explained by the inclusion of cases of HS-MS overlapping other chronic liver diseases in the comparison group, because this finding is relatively common in schistosome-endemic areas.

[Pediatric Tuberculosis: 12 Years of Experience in a Tertiary Referral Center in Portugal]. / Tuberculose em Idade Pediátrica: Experiência de 12 Anos num Centro Terciário de Referência em Portugal.

INTRODUCTION: The diagnosis of tuberculosis in children is a challenge namely because extrapulmonary tuberculosis and severe disease are more frequent in this age group. The aim of this study was to evaluate and reflect about severe tuberculosis in pediatric age, in a metropolitan area of Lisbon. MATERIAL AND METHODS: Descriptive study about patients under 18 years of age admitted with tuberculosis disease in a tertiary pediatric hospital, from 2008 to 2019 (12 years). RESULTS: We report 145 patients, average of 12 cases/year, with an increase in the last three years. Median age of 12.9 years, 42.8% born in Portuguese-speaking African countries and 20% had a chronic disease. The diagnosis was pulmonary tuberculosis in 52.4% (n = 76) and extrapulmonary tuberculosis in 47.6%: lymphatic (n = 26), skeletal (n = 15), miliary (n = 8), meningeal (n = 7), peritoneal/ intestinal (n = 6), pleural (n = 4), renal (n = 1), cutaneous (n = 1), thoracic wall (n = 1) and salivary glands (n = 1). The tuberculin test was positive in 78/99 (78.8%) and Interferon Gamma Release Assay in 61/90 (67.8%). In 20.7% (n = 30) acid-fast bacilli were identified in gastric aspirate/sputum and the agent was identified in 59.3% (n = 86). Tuberculosis was resistant in 11% (n = 16). Patients with extrapulmonary tuberculosis were younger (p = 0.006) and had more prolonged therapy (p < 0.001). Therapy-related complications occurred in 11% (n = 16). One patient died (with terminal cancer). CONCLUSION: This study highlights the need for screening of tuberculosis in children from endemic countries, patients with immunosuppression and chronic disease.

Introdução: Em Pediatria, o diagnóstico de tuberculose constitui um desafio, pois a doença pode frequentemente manifestar-se através de formas graves e extrapulmonares. O objetivo deste estudo foi avaliar e refletir sobre a tuberculose grave com necessidade de internamento, em idade pediátrica, numa área metropolitana de Lisboa.Material e Métodos: Estudo descritivo de doentes com idade inferior a 18 anos, internados com o diagnóstico de tuberculose num hospital pediátrico terciário, de 2008 a 2019 (12 anos).Resultados: Identificados 145 doentes, numa média de 12 casos por ano, e um aumento do número de casos nos últimos três anos. A mediana de idades dos doentes era de 12,9 anos, 42,8% nascidos em países africanos de língua oficial portuguesa e 20% tinham doença crónica. Diagnosticou-se tuberculose pulmonar em 52,4% (n = 76) e tuberculose extrapulmonar em 47,6%: ganglionar (n = 26), óssea (n = 15), miliar (n = 8), meníngea (n = 7), peritoneal/intestinal (n = 6), pleural (n = 4), renal (n = 1), cutânea (n = 1), da parede torácica (n = 1) e glândulas salivares (n = 1). A prova tuberculínica foi positiva em 78/99 (78,8%) e o Interferon Gamma Release Assay em 61/90 (67,8%). Em 20,7% (n = 30) identificaram-se bacilos ácido-álcool resistentes no exame direto do suco gástrico/expetoração e o agente foi identificado em 59,3% (n = 86). A tuberculose resistente ocorreu em 11% (n = 16). Os doentes com tuberculose extrapulmonar eram mais jovens (p = 0,006) e fizeram tratamentos mais prolongados (p < 0,001). Ocorreram complicações da terapêutica em 11% (n = 16). Registou-se um óbito numa doente com neoplasia avançada.Conclusão: Este estudo alerta para a necessidade do rastreio da infeção em crianças de países endémicos, imunossuprimidos e com doença crónica.

Assessing Transfer Entropy in cardiovascular and respiratory time series under long-range correlations.

Heart Period (H) results from the activity of several coexisting control mechanisms, involving Systolic Arterial Pressure (S) and Respiration (R), which operate across multiple time scales encompassing not only short-term dynamics but also long-range correlations. In this work, multiscale representation of Transfer Entropy (TE) and of its decomposition in the network of these three interacting processes is obtained by extending the multivariate approach based on linear parametric VAR models to the Vector AutoRegressive Fractionally Integrated (VARFI) framework for Gaussian processes. This approach allows to dissect the different contributions to cardiac dynamics accounting for the simultaneous presence of short and long term dynamics. The proposed method is first tested on simulations of a benchmark VARFI model and then applied to experimental data consisting of H, S and R time series measured in healthy subjects monitored at rest and during mental and postural stress. The results reveal that the proposed method can highlight the dependence of the information transfer on the balance between short-term and long-range correlations in coupled dynamical systems.

Characterization of upper limb movement-related EEG dynamics through fractional integrated autoregressive modeling.

The analysis of electroencephalographic (EEG) series associated with movement performance is important for understanding the cortical neural control on motor tasks. While the existence of long-range correlations in physiological dynamics has been reported in previous studies, such a characterization in EEG series gathered during upper-limb movements has not been performed yet. To this end, here we report on a fractional integrated autoregressive analysis of EEG series during different functional classes of motor actions and resting phase, and data were gathered from 33 healthy volunteers. Results show significant differences in EEG long-range correlations on EEG series from characteristic topography.

Intravaginal electrical stimulation associated with pelvic floor muscle training for women with stress urinary incontinence: study protocol for a randomized controlled trial with economic evaluation.

INTRODUCTION: Pelvic floor muscle training (PFMT) exercises and neuromuscular electrical stimulation (NMES) are described as conservative interventions to prevent or treat female stress urinary incontinence (SUI). However, it has not been described yet the effect of PFMT associated to intravaginal NMES which evaluated the cost-effectiveness and cost-utility of treating. AIMS: To evaluate the effects of intravaginal NMES associated with the PFMT protocol on urinary loss and quality of life in women with SUI and to evaluate the cost-effectiveness and cost-utility and pelvic floor muscle in women with SUI. METHODS: Randomized controlled trial study with economic evaluation. Inclusion criteria are woman (biological), aged ≥ 18 years old and with a report of SUI ≥ once/week. Exclusion criteria are presence of vaginal or urinary infection, virginity, being in the gestational or puerperium period, or neurological disease. Participants will undergo physical therapy assessment and intervention: anamnesis, pelvic floor muscle assessment by vaginal palpation and manometry (PeritronTM), questionnaires (Short-Form 6 Dimensions-Brazil (SF-6D), King's Health Questionnaire (KHQ) and King´s Health Questionnaire for Scoring Algorithm), health costs, and voiding diary. Participants will be randomly allocated into 3 groups: CG (control group), IG 1 (intervention group 1, PFMT), and IG2 (intervention group 2, PFMT + NMES). The statistical analysis will be performed by intention to treat, and multivariate analysis of mixed effects will be used to compare outcomes. Effect size measurements will be calculated and will be provided by Cohen's d test. A significance level of 5% will be adopted. Additionally, the incremental cost-effectiveness and incremental cost-utility ratios will be used. DISCUSSION: This protocol can corroborate with the literature in order to identify the effect of techniques, based on the possibility of confirming the hypothesis that the NMES associated with PFMT performed concurrently will be the best treatment option; considering the effectiveness, cost-effectiveness, and cost-utility analysis, it will be used as an option for optimization of the treatment of SUI. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (ReBEC) ID: RBR-6gtzg4 . Registered on September 3, 2019.

Acaricide activity of extract and an isolated compound of Lithraea brasiliensis on Rhipicephalus microplus and selectivity actions against a non-target organism.

Rhipicephalus microplus, known as the cattle tick, is a cause of great economic losses for dairy cattle farming because of its high frequency of occurrence and the difficulty in controlling it. This research characterized the chemical profile and evaluated the in vitro toxicity of crude Lithraea brasiliensis extract and its isolated compound against acaricide-resistant and acaricide-susceptible R. microplus strains. Acaricidal activity was evaluated using a larval immersion test and the selectivity against non-target organisms was assessed on Artemia salina assay. The chemical investigation by high-performance liquid chromatography coupled with mass spectrometry (i.e., HPLC-MS) analysis showed the presence of hydrolysable tannins as well as urushiol derivatives. Column chromatography (CC) was carried out on the extract to obtain fractions and an isolated compound. The extract exhibited significant activity against acaricide-resistant (LC50 0.64 mg/mL) and acaricide-susceptible (LC50 0.76 mg/mL) strains of R. microplus larvae. The isolated compound from the extract (urushiol II), exhibited LC50 of 1.11 mg/mL for acaricide-resistant larvae. For acute toxicity in A. salina, the extract showed LC50>100 µg/mL. Thus, our findings represent the first effort to demonstrate the potential of L. brasiliensis extract and urushiol II as potential natural acaricides to replace or to be integrated into the conventional control of R. microplus larvae.