The pattern of growth hormone action in the mouse brain.

Growth hormone (GH) acts in numerous organs expressing the GH receptor (GHR), including the brain. However, the mechanisms behind the brain's permeability to GH and how this hormone accesses different brain regions remain unclear. It is well-known that an acute GH administration induces phosphorylation of the signal transducer and activator of transcription 5 (pSTAT5) in the mouse brain. Thus, the pattern of pSTAT5 immunoreactive cells was analyzed at different time points after intraperitoneal or intracerebroventricular GH injections. After a systemic GH injection, the first cells expressing pSTAT5 were those near circumventricular organs, such as arcuate nucleus neurons adjacent to the median eminence. Both systemic and central GH injections induced a medial-to-lateral pattern of pSTAT5 immunoreactivity over time, as GH-responsive cells were initially observed in periventricular areas and were progressively detected in lateral brain structures. Very few choroid plexus cells exhibited GH-induced pSTAT5. Additionally, Ghr mRNA was poorly expressed in the mouse choroid plexus. In contrast, some tanycytes lining the floor of the third ventricle expressed Ghr mRNA and exhibited GH-induced pSTAT5. The transport of radiolabeled GH into the hypothalamus did not differ between wild-type and dwarf Ghr knockout mice, indicating that GH transport into the mouse brain is GHR-independent. Also, single-photon emission computed tomography confirmed that radiolabeled GH rapidly reaches the ventral part of the tuberal hypothalamus. In conclusion, our study provides novel and valuable information about the pattern and mechanisms behind GH transport into the mouse brain.

Improved Perception of Aggression Under (un)Related Threat of Shock.

Anxiety shifts visual attention and perceptual mechanisms, preparing oneself to detect potentially threatening information more rapidly. Despite being demonstrated for threat-related social stimuli, such as fearful expressions, it remains unexplored if these effects encompass other social cues of danger, such as aggressive gestures/actions. To this end, we recruited a total of 65 participants and asked them to identify, as quickly and accurately as possible, potentially aggressive actions depicted by an agent. By introducing and manipulating the occurrence of electric shocks, we induced safe and threatening conditions. In addition, the association between electric shocks and aggression was also manipulated. Our result showed that participants have improved sensitivity, with no changes to criterion, when detecting aggressive gestures during threat compared to safe conditions. Furthermore, drift diffusion model analysis showed that under threat participants exhibited faster evidence accumulation toward the correct perceptual decision. Lastly, the relationship between threat source and aggression appeared to not impact any of the effects described above. Overall, our results indicate that the benefits gained from states of anxiety, such as increased sensitivity toward threat and greater evidence accumulation, are transposable to social stimuli capable of signaling danger other than facial expressions.

Cilia as Wnt signaling organelles.

Cilia and Wnt signaling have a complex relationship, wherein Wnt regulates cilia and, conversely, cilia may affect Wnt signaling. Recently, it was shown that Wnt receptors are present in flagella, primary cilia, and multicilia, where they transmit an intraciliary signal that is independent of ß-catenin. Intraciliary Wnt signaling promotes ciliogenesis, affecting male fertility, adipogenesis, and mucociliary clearance. Wnt also stimulates the beating of motile cilia, highlighting that these nanomotors, too, are chemosensory. Intraciliary Wnt signaling employs a Wnt-protein phosphatase 1 (PP1) signaling axis, involving the canonical Wnt pathway's inhibition of glycogen synthase kinase 3 (GSK3) to repress PP1 activity. Collectively, these findings support that cilia are Wnt signaling organelles, with implications for ciliopathies and cancer.

Oncology Education in Angola: Current Status and Recommendations for Improvement.

Angola, a country grappling with prevalent tropical diseases such as malaria, is witnessing an alarming rise in cancer-related deaths. Despite the escalating significance of cancer globally and in Angola, the nation's medical schools lack compulsory oncology disciplines in their curricula. This absence compromises the comprehensive training of medical students, preventing the development of integrated perspectives and skills crucial for addressing the growing cancer burden. This article, authored by the Angolan Oncology Research Group (AORG), proposes an oncology program for undergraduate medical students in Angola, aiming to bridge the educational gap. The program outlines discipline objectives, topics to be covered, class formats, and workload considerations.

Exploring the use of visual predictions in social scenarios while under anticipatory threat.

One of the less recognized effects of anxiety lies in perception alterations caused by how one weighs both sensory evidence and contextual cues. Here, we investigated how anxiety affects our ability to use social cues to anticipate the others' actions. We adapted a paradigm to assess expectations in social scenarios, whereby participants were asked to identify the presence of agents therein, while supported by contextual cues from another agent. Participants (N = 66) underwent this task under safe and threat-of-shock conditions. We extracted both criterion and sensitivity measures as well as gaze data. Our analysis showed that whilst the type of action had the expected effect, threat-of-shock had no effect over criterion and sensitivity. Although showing similar dwell times, gaze exploration of the contextual cue was associated with shorter fixation durations whilst participants were under threat. Our findings suggest that anxiety does not appear to influence the use of expectations in social scenarios.

Chromosome mapping of retrotransposon AviRTE in a Neotropical bird specie: Trogon surrucura (Trogoniformes; Trogonidae).

Avian genomes are characterized as being more compact than other amniotes, with less diversity and density of transposable elements (TEs). In addition, birds usually show bimodal karyotypes, exhibiting a great variation in diploid numbers. Some species present unusually large sex chromosomes, possibly due to the accumulation of repetitive sequences. AviRTE is a long interspersed nuclear element (LINE) recently discovered in the genomes of birds and nematodes, and it is still poorly characterized in terms of chromosomal mapping and phylogenetic relationships. In this study, we mapped AviRTE isolated from the Trogon surrucura genome into the T. surrucura (TSU) karyotype. Furthermore, we analyzed the phylogenetic relationships of this LINE in birds and other vertebrates. Our results showed that the distribution pattern of AviRTE is not restricted to heterochromatic regions, with accumulation on the W chromosome of TSU, yet another species with an atypical sex chromosome and TE hybridization. The phylogenetic analysis of AviRTE sequences in birds agreed with the proposed phylogeny of species in most clades, and allowed the detection of this sequence in other species, expanding the distribution of the element.

Frequent disturbances enhanced the resilience of past human populations.

The record of past human adaptations provides crucial lessons for guiding responses to crises in the future1-3. To date, there have been no systematic global comparisons of humans' ability to absorb and recover from disturbances through time4,5. Here we synthesized resilience across a broad sample of prehistoric population time-frequency data, spanning 30,000 years of human history. Cross-sectional and longitudinal analyses of population decline show that frequent disturbances enhance a population's capacity to resist and recover from later downturns. Land-use patterns are important mediators of the strength of this positive association: farming and herding societies are more vulnerable but also more resilient overall. The results show that important trade-offs exist when adopting new or alternative land-use strategies.

Evolution of bird sex chromosomes: a cytogenomic approach in Palaeognathae species.

BACKGROUND: Different patterns of sex chromosome differentiation are seen in Palaeognathae birds, a lineage that includes the ratites (Struthioniformes, Rheiformes, Apterygiformes, Casuariiformes, and the sister group Tinamiformes). While some Tinamiform species have well-differentiated W chromosomes, both Z and W of all the flightless ratites are still morphologically undifferentiated. Here, we conducted a comprehensive analysis of the ZW differentiation in birds using a combination of cytogenetic, genomic, and bioinformatic approaches. The whole set of satDNAs from the emu (Dromaius novaehollandiae) was described and characterized. Furthermore, we examined the in situ locations of these satDNAs alongside several microsatellite repeats and carried out Comparative Genomic Hybridizations in two related species: the greater rhea (Rhea americana) and the tataupa tinamou (Crypturellus tataupa). RESULTS: From the 24 satDNA families identified (which represent the greatest diversity of satDNAs ever uncovered in any bird species), only three of them were found to accumulate on the emu's sex chromosomes, with no discernible accumulation observed on the W chromosome. The W chromosomes of both the greater rhea and the emu did not exhibit a significant buildup of either C-positive heterochromatin or repetitive DNAs, indicating their large undifferentiation both at morphological and molecular levels. In contrast, the tataupa tinamou has a highly differentiated W chromosome that accumulates several DNA repeats. CONCLUSION: The findings provide new information on the architecture of the avian genome and an inside look at the starting points of sex chromosome differentiation in birds.

Validation of the Equidyn protocol for evaluation of dynamic balance in older adults through a smartphone application.

BACKGROUND: Different tasks and proxy measurements have been employed to evaluate dynamic balance in older individuals. However, due to inherent limitations, results from most evaluations could hardly be taken as valid measurements of dynamic balance. RESEARCH QUESTION: Is the Equidyn smartphone application-based protocol valid and sensitive for assessment of dynamic balance in older adults? METHODS: Dynamic balance was evaluated in 52 physically active individuals, age range 60-80 years (M = 69.36). The dynamic tasks were one-leg sway either in the mediolateral (ML) or anteroposterior (AP) direction while supported on the contralateral leg, and cyclic sit-to-stand with a narrow support base. These tasks were performed under standardized movement amplitude and rhythm. Outcomes were correlated with unipedal quiet standing. A smartphone was attached to the trunk backside, and a custom-made application (Equidyn) was employed to provide guidance throughout evaluation, timed beeps to pace the movements, and three-dimensional trunk acceleration measurement for balance evaluation. RESULTS: Our data showed (a) that both ML and AP leg sway tasks were sensitive to aging and to direction of leg sway movements; (b) referenced to quiet unipedal stance, moderate/strong correlations for the ML/AP leg sway tasks and moderate correlations for the sit-to-stand task; and (c) moderate/strong correlations between the ML and AP leg sway tasks, and moderate correlations between the sit-to-stand and the two unipedal dynamic tasks in the ML acceleration direction. SIGNIFICANCE: The current results support the conclusion that the Equidyn protocol is a sensitive and valid tool to evaluate dynamic balance in healthy older individuals. The protocol tasks standardized in amplitude and rhythm favor their reproducibility and trunk acceleration data interpretation. As the whole assessment is made through a smartphone application, this dynamic balance evaluation could be made in a low-cost simple way both in the laboratory and clinical settings.

Ilheus Virus (ILHV) Resistance in Culex quinquefasciatus from the Northern Region of Brazil.

BACKGROUND: Orthoflavivirus ilheusense (ILHV) is a member of the Flaviviridae family. It was first isolated in 1944 from pools of Aedes serratus and Psorophora ferox mosquitoes; however, it has also been detected in species of the genus Culex, such as Cx. portesi and Cx. coronator. The objective of this study was to examine the vector competence of Cx. quinquefasciatus mosquitoes to ILHV infection and the subsequent transmission of the virus through their saliva during feeding on blood. METHODS: F1 generation females of Cx. quinquefasciatus (Ananindeua/PA) were orally infected with goose blood infected with strain BeH7445, and body, head and saliva samples were analyzed at 7, 14, and 21 dpi using the techniques of virus isolation in cells and indirect immunofluorescence. RESULTS: The presence of ILHV was not detected in the body and head samples of Cx. quinquefasciatus females at any of the three dpi's analyzed, indicating that the lineage of mosquitoes analyzed was resistant to ILHV. CONCLUSIONS: According to the results obtained in this study, the species Cx. quinquefasciatus proved resistant to ILHV, regardless of the virus titers to which it was exposed, which suggests the possibility that this species does not act as a vector in the ILHV transmission cycle.

Individual and contextual factors associated with the survival of patients with severe acute respiratory syndrome by COVID-19 in Brazil.

OBJECTIVE: To analyze the influence of individual and contextual factors of the hospital and the municipality of care on the survival of patients with Severe Acute Respiratory Syndrome due to COVID-19. METHODS: Hospital cohort study with data from 159,948 adults and elderly with Severe Acute Respiratory Syndrome due to COVID-19 hospitalized from January 1 to December 31, 2022 and reported in the Influenza Epidemiological Surveillance Information System. The contextual variables were related to the structure, professionals and equipment of the hospital establishments and socioeconomic and health indicators of the municipalities. The outcome was hospital survival up to 90 days. Survival tree and Kaplan-Meier curves were used for survival analysis. RESULTS: Hospital lethality was 30.4%. Elderly patients who underwent invasive mechanical ventilation and were hospitalized in cities with low tax collection rates had lower survival rates compared to other groups identified in the survival tree (p<0.001). CONCLUSION: The study indicated the interaction of contextual factors with the individual ones, and it shows that hospital and municipal characteristics increase the risk of death, highlighting the attention to the organization, operation, and performance of the hospital network.

Effects of environmental exposure to iron powder on healthy and elastase-exposed mice.

Prolonged exposure to iron powder and other mineral dusts can threaten the health of individuals, especially those with COPD. The goal of this study was to determine how environmental exposure to metal dust from two different mining centers in Brazil affects lung mechanics, inflammation, remodeling and oxidative stress responses in healthy and elastase-exposed mice. This study divided 72 male C57Bl/6 mice into two groups, the summer group and the winter group. These groups were further divided into six groups: control, nonexposed (SAL); nonexposed, given elastase (ELA); exposed to metal powder at a mining company (SAL-L1 and ELA-L1); and exposed to a location three miles away from the mining company (SAL-L2 and ELA-L2) for four weeks. On the 29th day of the protocol, the researchers assessed lung mechanics, bronchoalveolar lavage fluid (BALF), inflammation, remodeling, oxidative stress, macrophage iron and alveolar wall alterations (mean linear intercept-Lm). The Lm was increased in the ELA, ELA-L1 and ELA-L2 groups compared to the SAL group (p < 0.05). There was an increase in the total number of cells and macrophages in the ELA-L1 and ELA-L2 groups compared to the other groups (p < 0.05). Compared to the ELA and SAL groups, the exposed groups (ELA-L1, ELA-L2, SAL-L1, and SAL-L2) exhibited increased expression of IL-1ß, IL-6, IL-10, IL-17, TNF-α, neutrophil elastase, TIMP-1, MMP-9, MMP-12, TGF-ß, collagen fibers, MUC5AC, iNOS, Gp91phox, NFkB and iron positive macrophages (p < 0.05). Although we did not find differences in lung mechanics across all groups, there were low to moderate correlations between inflammation remodeling, oxidative stress and NFkB with elastance, resistance of lung tissue and iron positive macrophages (p < 0.05). Environmental exposure to iron, confirmed by evaluation of iron in alveolar macrophages and in air, exacerbated inflammation, initiated remodeling, and induced oxidative stress responses in exposed mice with and without emphysema. Activation of the iNOS, Gp91phox and NFkB pathways play a role in these changes.

A novel hantavirus identified in bats (Carollia perspicillata) in Brazil.

Bats play an essential role in maintaining ecosystems. Their unique characteristics increase the likelihood of interactions with various species, making them a potential source for the emergence and spread of infectious diseases. Hantaviruses are continuously expanding their range of hosts. This study presents the identification of a partial genome associated with Hantavirus in samples collected from neotropical bats. We conducted a metagenomic study using samples from Carollia perspicillata in Maranhão, Brazil. Tissue fragments were used for RNA extraction and subsequent sequencing. The resulting data was subjected to bioinformatic analysis. A sequence showing an identity of 72.86% with the L gene in the reference genome was obtained. The phylogenetic analysis revealed the study sequence, denoted as Buritiense, clustering within the Mobatvirus clade. The intragroup analysis showed a broader dispersion and were markedly asymmetric. This observation suggests the possibility that Buritiense could potentially represent a new species within the bat-borne hantaviruses, but further analyses are needed to provide additional insights if bats plays a role as reservoirs and the potential for transmission to human populations.

Once upon a fly: The biogeographical odyssey of Labrundinia (Chironomidae, Tanypodinae), an aquatic non-biting midge towards diversification.

Labrundinia is a highly recognizable lineage in the Pentaneurini tribe (Diptera, Chironomidae). The distinct predatory free-swimming larvae of this genus are typically present in unpolluted aquatic environments, such as small streams, ponds, lakes, and bays. They can be found on the bottom mud, clinging to rocks and wood, and dwelling among aquatic vegetation. Labrundinia has been extensively studied in ecological research and comprises 39 species, all but one of which has been described from regions outside the Palearctic. Earlier phylogenetic studies have suggested that the initial diversification of the genus likely occurred in the Neotropical Region, with its current presence in the Nearctic Region and southern South America being the result of subsequent dispersal events. Through the integration of molecular and morphological data in a calibrated phylogeny, we reveal a complex and nuanced evolutionary history for Labrundinia, providing insights into its biogeographical and diversification patterns. In this comprehensive study, we analyze a dataset containing 46 Labrundinia species, totaling 10,662 characters, consisting of 10,616 nucleotide sites and 46 morphological characters. The molecular data was generated mainly by anchored enrichment hybrid methods. Using this comprehensive dataset, we inferred the phylogeny of the group based on a total evidence matrix. Subsequently, we employed the generated tree for time calibration and further analysis of biogeography and diversification patterns. Our findings reveal multiple dispersal events out of the Neotropics, where the group originated in the late Cretaceous approximately 72 million years ago (69-78 Ma). We further reveal that the genus experienced an early burst of diversification rates during the Paleocene, which gradually decelerated towards the present-day. We also find that the Neotropics have played a pivotal role in the evolution of Labrundinia by serving as both a cradle and a museum. By "cradle," we mean that the region has been a hotspot for the origin and diversification of new Labrundinia lineages, while "museum" refers to the region's ability to preserve ancestral lineages over extended periods. In summary, our findings indicate that the Neotropics have been a key source of genetic diversity for Labrundinia, resulting in the development of distinctive adaptations and characteristics within the genus. This evidence highlights the crucial role that these regions have played in shaping the evolutionary trajectory of Labrundinia.

Soluble guanylate cyclase stimulators and activators: new horizons in the treatment of priapism associated with sickle cell disease.

Priapism, defined as a prolonged and often painful penile erection occurring without sexual stimulation or desire, is a common complication in sickle cell disease (SCD), affecting up to 48% of male patients. This condition presents significant clinical challenges and can lead to erectile dysfunction if not properly managed. Current pharmacological treatments for SCD-related priapism are primarily reactive rather than preventative, highlighting a gap in effective medical intervention strategies. A critical factor in developing priapism is the reduced basal bioavailability of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in erectile tissues. New prevention strategies should ideally target the underlying pathophysiology of the disease. Compounds that stimulate and activate soluble guanylate cyclase (sGC) emerge as potential therapeutic candidates since these compounds have the property of inducing cGMP production by sGC. This review explores the potential of sGC stimulators and activators in treating priapism associated with SCD. We discuss the advantages of these agents in the face of the challenging pathophysiology of SCD. Additionally, the review underscores the impact of intravascular hemolysis and oxidative stress on priapism pathophysiology in SCD, areas in which sGC stimulators and activators may also have beneficial therapeutic effects.

Physicochemical and mechanical properties of preheated composite resins for luting ceramic laminates.

This study analyzed and compared the physicochemical and mechanical properties of preheated resin composite with light-cured resin cement for luting indirect restorations. 210 specimens of resin cement/resin composite were prepared according to preheating treatment heated (Htd) or not (NHtd). Light-cured resin cement (Variolink Veneer, Ivoclar), and resin composite (Microhybrid-Z100, 3 M; Nanohybrid-Empress direct, Ivoclar; and Bulk fill-Filtek One, 3 M) were used (n = 10). Resin cement specimens were not preheated. The response variables were (n = 10): film thickness, microhardness, liquid sorption and solubility. Data were analyzed by 2-way ANOVA and Tukey HSD post-test (α = 0.05). Bulk fill NHtd resin had the highest film thickness values (p < 0.001). Microhybrid and nanohybrid Htd resins had the smallest thicknesses and did not differ from the cement (p > 0.05). The highest microhardness values were found for Bulk fill NHtd and Bulk fill Htd resins. The nanohybrid and microhybrid Htd resins showed the lowest microhardness values, with no difference in cement (p > 0.05). For liquid sorption, there was no significant difference between the groups (p = 0.1941). The microhybrid Htd resin showed higher solubility values than the other materials (p = 0.0023), but it did not differ statistically from resin cement (p > 0.05). Preheating composite resins reduced the film thickness. After heating, nanohybrid and Bulk fill resins retained stable microhardness, sorption, and solubility values.

Responses of two Anastrepha species' immature stages infesting preferential hosts to different temperature exposures.

Anastrepha fraterculus (Wiedemann) and A. obliqua (Macquart) are important pests of fruit crops. In Brazil, these species cause damage to fruit growing in the South (annual average temperature of 20.9 °C) and Northeast (average yearly temperature of 24 °C). We evaluated the effect of temperature on the viability and development time of A. fraterculus and A. obliqua immature stages in their respective preferred hosts, guava (Psidium guajava L., Myrtaceae) and mango (Mangifera indica L., Anacardiaceae). The duration of egg and pupal stages, egg to pre-pupa, and viability of egg and pupal stages under different temperatures (15, 20, 25, 30, and 35 °C) were assessed. For both species, development time decreased with increasing temperature. Viability in the evaluated stages was only observed between 15 and 30 °C. However, the species responded differently to the exposure temperatures (15 and 30 °C), especially in the pupal stage and from egg to pre-pupa. Anastrepha fraterculus showed a lower tolerance to high temperatures, especially in the pupal stage and from egg to pre-pupa, which may explain its lower importance and economic impact in warmer Brazilian regions. Anastrepha obliqua had a lower tolerance at 15 °C, indicating greater adequacy for temperatures above 20 °C, characteristic of Northeast Brazil, suggesting the capacity to spread to cooler areas with rising temperatures.

First Report of Metadelphax propinqua (Fieber) (Hemiptera: Delphacidae) Feeding on Bermudagrass in Brazil.

Bermudagrass (Cynodon dactylon (L.) Pers., Poaceae) is one of the most important pasture grasses used in milk production systems in southern Brazil, with an increasing expansion of cultivated areas in recent years. Here, we report the first occurrence of the planthopper Metadelphax propinqua (Fieber) (Hemiptera: Delphacidae) feeding on bermudagrass in Brazil. Population outbreaks of this species were observed in January/February 2023 in a commercial hay production farm in the municipality of Chapecó, Santa Catarina State, southern Brazil. Metadelphax propinqua was found in association with three cultivars of C. dactylon (Tifton 85, Jiggs, and Vaquero). The infested plants showed leaf chlorosis and a reduced plant growth rate due to sap sucking and toxin injection as well as honeydew deposition on the leaves, which led to the development of sooty mold. In addition, this delphacid species has been reported as a vector of important pathogens to bermudagrass species and other row crops. Thus, M. propinqua is a potential pest of bermudagrass in Brazil and should be monitored to assess its establishment and behavior in Brazilian pasturelands.

Comparison between ultrasonography and computed tomography for measuring skeletal muscle mass in critically ill patients with different body mass index.

BACKGROUND & AIM: Among critical patients, there is an early onset of changes in both the quantity and quality of muscle mass. It is essential to find tools that promptly identify this muscle mass loss. The aim of this study was to compare the ultrasonography of the quadriceps femoris to the gold standard, thigh computed tomography (CT) for assessing the musculature of critically ill patients with different body mass index who have suffered traumatic brain injury. METHODS: This is a prospective validation study in an Intensive Care Unit (ICU) specialized in trauma care, located at a tertiary teaching hospital. Our study involved a convenience sample of patients. Sequential ultrasound and CT scans were performed at three distinct time intervals: upon admission, between 24 and 96 h' post-admission, and finally, between 96 and 168 h' post-admission. For all ultrasound measurements, we conducted simultaneous quadriceps CT measurements. The correlation between measurements obtained by ultrasound and computed tomography at three different times and in three BMI ranges was analyzed, in individuals with normal weight, overweight and obese. RESULTS: Results: We analyzed 252 images in 49 patients in time 1, 40 patients in time 2, and 37 in time 3 to compare the thickness quadriceps muscle using US and CT. Of these, 18 patients had a BMI ≤ 24.9 kg/m2 (normal weight), 18 patients from 25 to 29.9 kg/m2 (overweight), and 8 patients had a BMI ≥ 30 kg/m2 (obese). The mean age was 37 years, the majority (94%) were male and the main comorbidities were: hypertension 12%, diabetes 4% and 14% smoking. The results revealed minor discrepancies between measurements obtained through the two methods, these changes were not influenced by the body mass index, with these variations being practically insignificant in the context of clinical application. Thus, the correlation and concordance between the values obtained found a strong positive correlation with good limits of agreement. The Spearman's correlation coefficients obtained were r = 0.89, 0.91 and 0.88, p < 0.01 at T1, T2 and T3 respectively for normal weight, r = 0.91, 0.80 and 0.81, p < 0.01 at T1, T2 and T3 respectively for overweight and r = 0.89, 0.94 and 0.84, p < 0.01 at T1, T2 and T3 respectively for obesity. In addition to a positive correlation, we observed a high agreement between the methods. The Bland & Altman analysis at time 1 showed, respectively, the bias of 1.46, 2.03 and 0.76. At time 2, the bias was 0.42, 3.11 and 2.12. At time 3, the bias was 2.26, 3.38 and 2.11 mm. CONCLUSION: Our findings suggest that measure femoral quadriceps muscle thickness ultrasound-based exhibits a comparable performance to thigh CT. This conclusion stems from the excellent correlation and good agreement observed between ultrasound and CT, which is considered the gold standard for muscle assessment in critically ill patients. TRIAL REGISTRATION: This clinical trial is registered at REBEC https://ensaiosclinicos.gov.br/ identifier: RBR-2bzspnz. The protocol was approved, on July 30, 2019, by the Research Ethics Committee of the Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto - Trial Registration Number: 3,475,851.