Metastatic organotropism: a brief overview.

Organotropism has been known since 1889, yet this vital component of metastasis has predominantly stayed elusive. This mini-review gives an overview of the current understanding of the underlying mechanisms of organotropism and metastases development by focusing on the formation of the pre-metastatic niche, immune defenses against metastases, and genomic alterations associated with organotropism. The particular case of brain metastases is also addressed, as well as the impact of organotropism in cancer therapy. The limited comprehension of the factors behind organotropism underscores the necessity for efficient strategies and treatments to manage metastases.

Association of Weight Change, Inflammation Markers and Disease Staging with Survival of Patients Undergoing Chemotherapy for Pancreatic Adenocarcinoma.

INTRODUCTION: Cancer-associated-cachexia represents a systemic syndrome of unintended weight-loss (WL) and systemic inflammation, affecting >80% patients with pancreatic adenocarcinoma (PA). We aimed to evaluate the association of weight change (WC) with survival of patients treated with chemotherapy (ChT) for PA and the influence of disease staging. We also studied the prognostic and predictive value of inflammation-based scores. METHODS: Observational, retrospective cohort study. Individuals were divided into two cohorts, according to WC (WL ≥5% vs. non-WL <5%) after ChT. Main endpoints were weight change and survival time. Statistical analysis was performed using Stata software. RESULTS: Sixty-five patients were included (median age 69; 48% female), 60% with advanced disease. At 3 months after ChT start, 54% experienced WL. Advanced disease independently predicted WL (OR 2.10; 95% CI, 1.11-19.6; p = 0.041). With median follow-up of 14.8 mo, median survival time of patients with WL was 18.5 mo, vs. 33.2 vs. for non-WL (HR 2.28; 95% CI, 1.15-4.52; p = 0.019). In patients with early-stage disease, WL was associated with decreased survival time (21.9 vs. 67.6 mo; HR 23.68; 95% CI 2.39-234.75; p = 0.007), while the association of WL on survival time in advanced disease was not significant (HR 0.74; 95% CI, 0.34-1.60; p = 0.449). The multivariate survival model showed that WL (HR 1.11, 95% CI 1.03-1.20, p = 0.005) and cachexia (HR 3.76, 95% CI 1.07-13-18), p = 0.041) were associated with survival time, as well as location in body or tail (HR 3.05; 95% CI, 1.75-5.31; p < 0.001) and high Neutrophil-to-lymphocyte ratio (NLR) at 3 months (HR 6.20; 95% CI, 2.59-14.87; p < 0.001). CONCLUSION: WL was an independent prognostic factor for survival. Particularly in early stage disease, interventions targeting this modifiable factor may translate into better outcomes for PA patients. NLR may be a surrogate marker of systemic inflammatory status in this setting.

Survival and preference of cotton boll weevil adults for alternative food sources / Sobrevivência e preferência para exploração de recursos de adultos do bicudo do algodoeiro

Abstract Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus’ flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Resumo Plantas que podem ser uma fonte potencial de recursos alimentares (néctar floral, pólen e tecidos vegetais) para o bicudo do algodoeiro durante a entressafra foram avaliadas, considerando as condições ambientais prevalentes na região de Cerrado do Brasil Central. Primeiro, testamos a adequação nutricional dos recursos (pólen e néctar) fornecidos por oito espécies de plantas (erva-doce, margaridão, mamona, quiabo, hibisco, sorgo, feijão guandu e crotalária) como único recurso alimentar para a sobrevivência do inseto. Posteriormente, nós avaliamos se os recursos fornecidos pelas plantas selecionadas continuaram a serem explorados pelo bicudo na presença do algodoeiro, seu recurso alimentar principal. A longevidade média do bicudo do algodoeiro foi significativamente maior quando eles foram alimentados com flores de hibisco (166,6 ± 74,4) e quiabo (34,7 ± 28,9) do que quando alimentados com flores das outras seis espécies. Em seguida, a preferência do bicudo no uso de recursos foi comparada contrastando o quiabo e o hibisco com o algodão, em experimentos de dupla escolha. Os bicudos preferiram as plantas das três espécies na fase reprodutiva em relação àquelas em estádios vegetativos. Embora a preferência por plantas de algodão na fase reprodutiva tenha sido maior, os bicudos preferiram plantas em floração de quiabo e hibisco quando estas foram contrastadas com o algodão na fase vegetativa.

Survival and preference of cotton boll weevil adults for alternative food sources.

Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus' flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Output relations of humeral circumflex arteries and its variations / Relaciones de las arterias circunflejas humerales y sus variaciones

A large range of variability marks the branching pattern of the axillary artery. The knowledge of the anatomical variations and this pattern is essential to diagnostic and therapeutic approaches, including surgery, of the axillary region. The aim of this study was to observe the different possible origins of circumflex humeral arteries and to measure the length and diameter of each vessel. In our study, 24 armpits from adult cadavers (fixed in tamponed formalin 10%) were dissected. The data were analyzed with a digital caliper and the results expressed as Mean ± SD. In majority of specimens, posterior circumflex humeral artery (PCHA) arose from subscapular artery (SSA) (54.16%) and had an average diameter of 3.92±0.41 mm. The anterior circumflex humeral artery was a branch from axillary artery (AA) in the majority of the specimens (62.5%) with an average diameter of 1.83±0.68 mm. Circumflex humeral arteries can arise from SSA, deep brachial artery and AA. The result of this study is an interesting data for origin, length and diameter of these vessels, contributing to the knowledge of these variations occurrence.

Una amplia gama de variabilidad marca el patrón de ramificación de la arteria axilar. El conocimiento de las variaciones anatómicas de este patrón es esencial para enfoques de diagnóstico y terapéuticos, incluyendo la cirugía de la región axilar. El objetivo fue observar los diferentes orígenes posibles de arterias circunflejas humerales y medir la longitud y el diámetro de cada vaso. En el estudio se disecaron 24 axilas de cadáveres adultos (fijados en formalina tamponada al 10%). Los datos se analizaron con un calibrador digital y los resultados se expresaron como Media ± DS. En la mayoría de los especímenes, la arteria circunfleja humeral posterior surgió de la arteria subescapular (ASE) (54,16%) con un diámetro medio de 0,41±3,92 mm. En la mayoría de los especímenes (62,5%), la arteria circunfleja humeral anterior era una rama de la arteria axilar (AA) con un diámetro medio de 0,68±1,83 mm. Las arterias circunflejas humerales pueden surgir de la ASE, de la arteria braquial profunda y AA. El resultado de este estudio es un dato interesante para el origen, la longitud y el diámetro de los vasos, lo que contribuye al conocimiento de la ocurrencia de estas variaciones.

Can information on remaining time modulate psychophysiological parameters during an intermittent exercise?

AIM: The purpose of the present study was to verify the effect of information on remaining time on physiological and perceptual responses during an intermittent exercise. METHODS: Ten trained cyclists participated in this study (176 ± 0.4 cm; 78.5 ± 10.4 kg; 32.5 ± 6 years; peak power output: 369.8 ± 37.8 W; VO(2peak): 51.90 ± 10.37 mL/kg/min). An intermittent cycling protocol consisting of four minutes at low-intensity (50% PPO) intervals followed by one-minute high-intensity bouts (100% PPO) under three different conditions were performed: OL40=40 min open-loop with no information on remaining time; CLI40=40 min closed-loop with information on remaining time; and CLI20=20 min closed-loop with information on remaining time. Ventilatory data (VO2) and electromyographic signals (EMG) were continuously recorded, and rating of perceived exertion (RPE) was acquired at the end of the high-intensity periods. RESULTS: Results indicated that the oxygen consumption and muscle activity during OL40 were lower than CLI40. OL40 also demonstrated significantly lower VO2values compared to CLI20 during high-intensity periods at 10 and 20 min. Root mean square values from EMG data for OL40 during high-intensity periods were significantly lower at 40 min compared with CLI40, and when the high-intensity period median frequencies among protocols were compared, CLI40 presented significantly higher values than the other conditions at 5 and 10 min. CONCLUSION: Even when power output is maintained, information on remaining time may alter peripheral responses through a complex saving component to prevent higher energy expenditure during physical exercise.

Evaluation of mortadella formulated with carbon monoxide-treated porcine blood.

The proximate composition and color of mortadellas containing carbon monoxide-treated (COTB), untreated (UNTB), or CO-treated dried blood (CODB) were compared to that of control mortadella. Blood addition did not affect (P>0.05) the proximate composition and TBARS. The mortadella containing 10% UNTB were brown and those containing COTB or CODB were red. Residual nitrite level, L*, a*, b* and c* values of the mortadella decreased (P<0.05) with an increase in the amount of blood; TBARs did not vary (P>0.05). Increasing the amount of blood increased (P<0.05) the hue angle (h*) and browning index (BI) of the mortadella containing UNTB. Increasing blood addition decreased (P<0.05) h* and did not affect (P>0.05) BI. Increasing storage length decreased (P<0.05) residual nitrite, affected BI and color coordinates and did not affect TBARS (P>0.05). Addition of CO-treated blood allows the production of better-colored sausages having lower residual nitrite levels.

Does prefrontal cortex transcranial direct current stimulation influence the oxygen uptake at rest and post-exercise?

The study evaluated the effect of transcranial direct current stimulation (tDCS) applied over prefrontal cortex on the oxygen uptake (V˙ O2) at rest and during post-exercise recovery. The V˙ O2 was assessed in eleven healthy subjects before, during tDCS (sham or anodal tDCS, 2 mA, 20 min), and 30-min following isocaloric aerobic exercise (~200 kcal). During tDCS, no changes were observed on V˙ O2 compared to baseline (P=0.95) and sham condition (P=0.85). The association between isocaloric exercise and anodal tDCS increased the V˙ O2 throughout 30-min recovery compared to sham condition (P<0.001). Therefore, the energy expenditure within the excess post-exercise oxygen consumption (EPOC) period, after anodal tDCS was approximately 19% higher compared to the sham condition (P<0.05). In conclusion, anodal tDCS applied on the prefrontal cortex combined with submaximal aerobic exercise increased the EPOC, enhancing the V˙ O2 and energy expenditure at least for 30-min of recovery.

Uranium deposition in bones of Wistar rats associated with skeleton development.

Sixty female Wistar rats were submitted to a daily intake of ration doped with uranium from weaning to adulthood. Uranium in bone was quantified by the SSNTD (solid state nuclear track detection) technique, and bone mineral density (BMD) analysis performed. Uranium concentration as a function of age exhibited a sharp rise during the first week of the experiment and a drastic drop of 70% in the following weeks. Data interpretation indicates that uranium mimics calcium. Results from BMD suggest that radiation emitted by the incorporated Uranium could induce death of bone cells.

Field evaluation of Bt cotton crop impact on nontarget pests: cotton aphid and boll weevil.

Bt cotton plants expressing Cry1Ac protein have high specificity for the control of lepidopteran larvae. However, studies conducted in several countries have shown these plants have a differential impact on nontarget herbivores. The aim of this study was to compare the colonization rates and population abundance of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) and the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), in plots of Bt (Nuopal) and non-Bt cotton (Delta Opal) in an experimental field in Brasilia, DF, Brazil. No difference was observed in the preference and colonization by winged aphids to plants from the two treatments. There was no significant difference in abundance of wingless aphids or in the production of winged aphids between treatments. Apparently, the parameters that control factors such as fecundity, survival, and dispersal were similar on both Bt and non-Bt plants. Monitoring of plants for coccinellids, a specialist predator of aphids, and ants that act on the dispersal of aphids among plants showed no significant difference between Bt and non-Bt plants, supporting the inference above. Regarding the effect on boll weevil, there was also no significant difference between treatments in the total number of fruiting structures attacked in each plot, the percentage of fruiting structures attacked per plant or on the number of weevils emerging from fruits with boll weevil damage from egg-laying, when damaged fruit samples were held in the laboratory. Based on these results, we conclude that there is no impact of Bt cotton crop expressing Cry1Ac on the nontarget herbivores tested under field conditions.

Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.

The boll weevil (Anthonomus grandis Boheman) (Coleoptera: Curculionidae) is an introduced pest in Brazil, which in 30 yr has successfully expanded to various eco-regions and became the most important pest of cotton (Gossypium hirsutum, Malvaceae). Given the limited knowledge about the adaptive mechanisms that allowed successful establishment of the pest population in a tropical region, in this work we studied the potential of the Midwest population of boll weevils to enter a reproductive dormancy and identified the importance of the feeding source for induction of dormancy. We investigated morphological and physiological characters as indicators of the dormancy. We also investigated the occurrence of reproductive dormancy in boll weevils populations from cotton farms of the Midwestern region of Brazil during the cotton and noncotton seasons of 2009 and 2010. The studies revealed that boll weevils entered facultative reproductive dormancy; however, unlike what has been observed for boll weevils from temperate and subtropical regions, the hypertrophy of fat body and hexamerin levels did not straightly correlated to reproductive dormancy. The food source and field conditions during early adult development were decisive factor for the induction of reproductive dormancy. The incidence of reproductive dormancy increased progressively as the phenology of cotton plant advanced, reaching approximately 90% at the end of the crop season. During the noncotton season, the boll weevil was predominantly found in reproductive dormancy, especially females; however, there is evidence of use of multiple adaptive strategies to colonize the next harvest.

Conservação de inimigos naturais (Insecta) em tomateiro orgânico / Conservation of natural enemies (Insecta) in the organic tomato crop

A adoção de práticas culturais como o consórcio de culturas e o tipo de irrigação podem beneficiar a comunidade de inimigos naturais no agroecossistema ao disponibilizar micro-habitas mais favoráveis e recursos alternativos, principalmente em períodos de baixa precipitação pluviométrica. O objetivo deste trabalho foi avaliar como o consórcio tomate + coentro e o tipo de irrigação (gotejamento e aspersão) podem beneficiar a comunidade de inimigos naturais no agroecossistema do tomateiro. O trabalho foi realizado no campo experimental da Embrapa Hortaliças, Gama, DF, de setembro a novembro de 2008. Os tomateiros foram plantados em monocultura ou consorciados com o coentro e irrigados por gotejamento e por aspersão (três repetições por tratamento), formando dois conjuntos de parcelas experimentais de acordo com o tipo de irrigação. A comunidade de inimigos naturais foi amostrada por observações diretas em 20 plantas de tomate por parcela e nas plantas de coentro sacudindo-se as plantas em cima de uma bandeja onde eram coletados os insetos. A abundância, riqueza e diversidade das espécies de inimigos naturais foram maiores nas parcelas cultivadas com coentro, independente do sistema de irrigação. Nas parcelas plantadas em monocultura foram encontradas mais espécies quando o tomateiro foi irrigado por aspersão. No entanto, a resposta de cada espécie de inimigo natural ou grupo de espécies foi distinta para o consórcio ou o tipo de irrigação. Portanto, em períodos de baixa precipitação, o consórcio tomate + coentro e a irrigação por aspersão podem favorecer a conservação de inimigos naturais no agroecossistema do tomateiro orgânico.

The adoption of cultural practices such as companion plants and the kind of irrigation system can benefit the community of natural enemies in the agroecosystem due to the increase of more favorable microhabitats available and as a source of alternative resources, mainly in periods of low precipitation. This study evaluated how the tomato + coriander intercrop and the kind of irrigation (drip and sprinkler) could benefit the community of natural enemies in the tomato agroecosystem. This work was carried out in the experimental field of Embrapa Hortaliças, Gama, DF, from September to November 2008. The tomatoes were planted in monoculture or with coriander (companion plant) and irrigated by drip and sprinkler irrigation (three replicates per treatment), forming two groups of experimental plots according to the kind of irrigation. The community of natural enemies was sampled by the direct observation of specimens on 20 tomatoes plants per plot and in the treatments. Coriander plants were shaken over a plastic tray for collection of insects. The abundance, richness and diversity of natural enemies were higher in tomato + coriander plots, regardless of the irrigation system. We observed more species of natural enemies in tomato monoculture plots when it was irrigated by sprinkler irrigation. However, the cultural practices adopted had a different effect on each species or group of species. Therefore, in periods of low precipitation, the tomato + coriander consortium associated with sprinkler irrigation can enhance the conservation of natural enemies in the organic tomato agroecosystem.

The relationship between rating of perceived exertion and muscle activity during exhaustive constant-load cycling.

The aims of this study were to verify the relationship between rating of perceived exertion (RPE) and electromyography (EMG) increases during exhaustive constant-load cycling bouts and, to compare and to correlate the power outputs corresponding to perceived exertion threshold (PET) and neuromuscular fatigue threshold (NFT). 11 men completed 3-4 different exhaustive constant-load cycling bouts on a cycle ergometer, being RPE and EMG measured throughout the bouts. The linear regression of the RPEslope and EMGslope against the power output identified the PET and NFT intensity, respectively. There was a significant relationship between RPEslope and EMGslope (R(2)=0.69; P<0.01). However, the linearity of RPEslope (R(2)=0.93±0.07) was significantly higher (P<0.001) than EMGslope (R(2)=0.63±0.25). In addition, the RPEslope and EMGslope were related to time to exhaustion (r=-0.59 and r=-0.60; P<0.001). There was no significant difference (P=0.42) between PET (201.5±27.9W) and NFT (210.3±22.6W) and they were significantly correlated (r=0.78; P=0.005). Therefore, the RPE and EMG increases during exhaustive constant-load cycling bouts are related and, PET and NFT intensities are similar and closely associated.

Pattern of use of emergency oral contraception among Portuguese women.

OBJECTIVE: This study describes the purchasers' profile and characterizes the pattern of use of emergency oral contraception among pharmacy users. SETTING: The study was carried out in 455 Portuguese pharmacies. METHOD: A cross-sectional study was undertaken in which pharmacists selected the first six purchasers of emergency oral contraception between May and June of 2006. Only user-purchasers were eligible to answer the questions about emergency oral contraception use. Participants completed a questionnaire on sociodemographic data and variables concerning contraceptive methods (including the emergency oral contraceptive acquired, the source of information about the availability of this emergency contraceptive method, prior use of emergency oral contraception, the frequency of use in the current cycle, the frequency of use in the preceding year, the time elapsed between unprotected sexual intercourse and the acquisition of emergency oral contraception, the reason for use and the regular method of contraception used). Although these drugs are available outside pharmacies--in some shops and supermarkets--their pattern of use was only assessed among pharmacy users. Descriptive statistics were used to characterize data. MAIN OUTCOME MEASURE: Prevalence of correct use, which was defined as the proportion of user-purchasers who acquired emergency oral contraception up to 72 h after unprotected sexual intercourse and had never used it in the current cycle. RESULTS: The sample comprised 1466 user-purchasers (72.6%) and 552 purchasers for another person's use (27.4%). Levonorgestrel-only contraceptives represented 96.1% of the emergency oral contraception acquired. User-purchasers aged between 18 and 30 represented 65.2% and 42.3% had attended secondary school. The majority of them (79.5%) were using a regular method of contraception and 62.6% were first-time users of emergency oral contraception. In 59.0% of the situations the reason for use was failure of the contraceptive used. CONCLUSION: Emergency oral contraception was used correctly by 96.9% of user-purchasers.

Comparison of electromyography fatigue threshold in lower limb muscles in trained cyclists and untrained non-cyclists.

The purpose of this study was to identify and compare the Electromyographic Fatigue Threshold (EMG(FT)) determined in the Vastus Lateralis (VL), Rectus Femoris (RF), Biceps Femoris (BF), Semitendinosus (ST) and Tibialis Anterior (TA) during stationary cycling in trained cyclists and non-cyclists. Using a cycle ergometer, 13 cyclists (28.4 +/- 6.9 years; 70.3 +/- 13 kg; 176.1 +/- 8.5 cm) and 11 non-cyclists (25.8 +/- 4 years; 73 +/- 9.1 kg; 175 +/- 6.4 cm), performed a maximum incremental test (ITmax) (90 rpm) to determine the (EMG(FT)). Maximal power output (W(PEAK)) reached by cyclists was higher than for non-cyclists (372.6 W and 248.9 W respectively) (P < 0.01). For the five muscles analyzed in cyclists, EMG(FT) occurred at 85.7% of cases in the VL, 92.9% in RE 78.6% in BE 78.6% in ST and 50% in TA, while in the non-cyclists group, this occurrence was 100% to muscle VL, 100% to RF, 92.6% to BF, 78.6% to ST, and 78.6% to TA. Analyzing the percentage corresponding to the power at EMG(FT) in relation to W(PEAK) reached, no differences between groups were observed for RF, BF and ST, however VL and TA, as well as the mean from all muscles were lower for cyclists than non-cyclists (P < 0.05). The present results showed that EMG(FT) is more easily identified in RF and VL muscles for both groups, and it may be an interesting method to evaluate the adaptive responses from aerobic and anaerobic metabolisms during cycling training programs.

Composition and color stability of carbon monoxide treated dried porcine blood.

Color stability of swine blood was studied over 12 weeks of storage in plastic bags, after pH (7.40, 6.70, or 6.00) adjustment, saturation with carbon monoxide (CO) and spray-drying. CO-treated dried blood presented a redder color and higher reflectance between 610 and 700 nm, compared to a brownish-red color and lower reflectance of untreated samples. As indicated by reflectance spectra, blood pH adjustment did not influence (P>0.05) the initial color of dried blood but influenced (P<0.05) its color stability (browning index). During storage, CO-treated blood showed a reduction in reflectance percentages as well as in CIE L(*) and a(*) values, which was more pronounced in polyethylene (OTR=4130 cm(3)/m(2)/day/atm) packaged samples. After 12 weeks of storage, CO-treated samples packaged in high OTR bags presented color indexes similar to those of the untreated dried samples. CO-treated samples packaged in nylon-polyethylene (OTR=30-60 cm(3)/m(2)/day/atm) bags showed a smaller rate of discoloration and color difference (DeltaE(*)) between the CO-treated and untreated samples. Even with some darkening, packaging CO-treated dry blood in low OTR bags still gives an acceptable reddish color after 12 weeks of storage while untreated dry blood has a brownish color just after drying.

Association between the electromyographic fatigue threshold and ventilatory threshold.

The objective of this study is to verify the coincidence between the occurrence of the electromyographic fatigue threshold (EMGth) and the ventilatory threshold (Vth) in an incremental test in the cyclosimulator, as well as to compare the calculation of the RMS from the EMG signal using different time windows. Thirteen male cyclists (73.7 +/- 12.4 kg and 174.3 +/- 6.2 cm) performed a ramp incremental test (TI) in a cyclosimulator until voluntary exhaustion. Before the start of each TI subjects had the active bipolar electrodes placed over the superficial muscles of the quadriceps femoris (QF) of the right leg: rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL). The paired student's t test, pearson's correlation coefficient and the analysis method described by Bland and Altman for the determination of the concordance level were used for statistical analysis. The significance level adopted was P < 0.05. Although no significant differences were found between Vth and the EMGth calculated from windows of 2, 5, 10, 30 and 60 seconds in the studied muscles, it is suggested that the EMGth values determined from the calculation of the RMS curve with windows of 5 and 10 seconds seem to be more appropriate for the calculation of the RMS curve and determination of EMGth from visual inspection.