Pneumococci isolated from children in community-based practice differ from isolates identified by population and laboratory-based invasive disease surveillance.

BACKGROUND: Characterizing strains causing noninvasive and invasive pneumococcal disease (IPD) may inform the impact of new pneumococcal conjugate vaccines (PCVs). METHODS: During 2011-2019, among children aged 6-36 months, pneumococcal serotype distribution and antibiotic non-susceptibility of nasopharyngeal and middle ear fluid (MEF) isolates collected at onset of acute otitis media (AOM) in Rochester, New York were compared with IPD isolates from Active Bacterial Core surveillance (ABCs) across 10 U.S. sites. RESULTS: From Rochester, 400 (nasopharyngeal) and 156 (MEF) pneumococcal isolates were collected from 259 children. From ABCs, 907 sterile-site isolates were collected from 896 children. Non-PCV serotypes 35B and 21 were more frequent among the Rochester AOM cases, while serotypes 3, 19A, 22F, 33F, 10A, and 12F contained in PCVs were more frequent among ABCs IPD cases. The proportion of antibiotic non-susceptible pneumococcal isolates was generally more common among IPD cases. In 2015-2019, serotype 35B emerged as the most common serotype associated with multiclass antibiotic non-susceptibility for both the Rochester AOM and ABCs IPD cases. CONCLUSIONS: Pneumococcal isolates from children in Rochester with AOM differ in serotype distribution and antibiotic susceptibility compared to IPD cases identified through U.S. surveillance. Non-PCV serotype 35B emerged as a common cause of AOM and IPD.

Surviving the Shocks: A Contemporary of Short-coupled Ventricular Fibrillation.

A young man presented following successful cardiac resuscitation after an out-of-hospital cardiac arrest. During his admission, he had multiple runs of short-coupled ventricular fibrillation with a similar morphology premature ventricular complex (PVC) trigger. He was brought to the electrophysiology laboratory, and, with a high dose of isoprenaline, the PVC was localised to the moderator band. Ablation induced short runs of ventricular tachycardia before elimination of the PVC. He subsequently underwent subcutaneous implantable cardiac defibrillator implantation before his discharge.

Enhancing Image-Guided Radiation Therapy for Pancreatic Cancer: Utilizing Aligned Peak Response Beamforming in Flexible Array Transducers.

To develop ultrasound-guided radiotherapy, we proposed an assistant structure with embedded markers along with a novel alternative method, the Aligned Peak Response (APR) method, to alter the conventional delay-and-sum (DAS) beamformer for reconstructing ultrasound images obtained from a flexible array. We simulated imaging targets in Field-II using point target phantoms with point targets at different locations. In the experimental phantom ultrasound images, image RF data were acquired with a flexible transducer with in-house assistant structures embedded with needle targets for testing the accuracy of the APR method. The lateral full width at half maximum (FWHM) values of the objective point target (OPT) in ground truth ultrasound images, APR-delayed ultrasound images with a flat shape, and images acquired with curved transducer radii of 500 mm and 700 mm were 3.96 mm, 4.95 mm, 4.96 mm, and 4.95 mm. The corresponding axial FWHM values were 1.52 mm, 4.08 mm, 5.84 mm, and 5.92 mm, respectively. These results demonstrate that the proposed assistant structure and the APR method have the potential to construct accurate delay curves without external shape sensing, thereby enabling a flexible ultrasound array for tracking pancreatic tumor targets in real time for radiotherapy.

Process Development and Scale-Up of a Novel Atypical DAT Inhibitor (S)-CE-123.

Large-scale syntheses of small molecules and kilo laboratories are crucial steps in drug development, especially in advanced stages. (S)-5-((Benzhydrylsulfinyl)methyl)thiazole, (S)-CE-123, a potent, selective, and novel atypical DAT inhibitor, has undergone iterative testing as part of the preclinical evaluation step. This required the process transfer, scale-up, and synthesis of a 1 kg preclinical batch. The Kagan protocol for asymmetric sulfide to sulfoxide oxidation was successfully applied within a four-step synthetic process for the successful upscaling of (S)-CE-123. During the scale-up of the last step, several changes were made to the original synthetic procedure, as with every increase in batch size, new problems had to be overcome. These include, among others, the workup optimization of the last step, the simplification of chromatographic purification, elution modification to improve the purity of the product and saving of workup time. Two washing steps were added to the original procedure to enhance both the yield and the enantiomeric excess value of the final product. The modifications introduced allowed access to a 1 kg (S)-CE-123 batch with a purity >99% and an enantiomeric excess value of 95%.

Pupil reflex as a marker of activity and prognosis in heart failure: a longitudinal and prospective study.

AIMS: Compensatory mechanisms in heart failure (HF) are triggered to maintain adequate cardiac output. Among them, hyperactivation of the sympathetic nervous system (SNS) is one of the main ones and carries a worse prognosis. The pupillary reflex depends on the SNS, and we can evaluate it through pupillometry. The aim of the study was to compare the differences in pupillary reflex between patients with acute HF and controls and to analyse whether these differences in pupillary reflex may offer a new and easy prognostic factor in such patients. METHODS AND RESULTS: We prospectively and consecutively included 107 patients admitted with decompensated HF. Quantitative pupillometry was performed with the NeuroOptics pupillometry during the first 24 h after admission and prior to discharge. The results were compared with those of a group of 100 healthy volunteers who also underwent pupillometry. The maximum baseline pupil size (MBPS) and the minimum pupil diameter (MPD) were measured. Patients with decompensated HF have a higher MBPS (3.64 ± 0.81) and higher MPD (2.60 ± 0.58) than HF patients at discharge and in the control group (P-value = 0.01 and 0.01, respectively). Also, HF patients presented an improvement in pupillometric values at discharge [MBPS (3.47 ± 0.79) and MPD (2.51 ± 0.58)] and showed no differences compared with the control group [MBPS (3.34 ± 0.82) and MPD (2.40 ± 0.53)] (P-value = 0.19 and 0.14, respectively). In addition, MBPS provides a good independent predictor of in-hospital and 1 month mortality in patients admitted with HF. Six patients (5.61%) died during hospital admission, and 11 patients (10.2%) died in the first month after discharge. Also, four patients (3.74%) were readmitted within 1 month of discharge. The receiver operating characteristic (ROC) curve for predicting in-hospital mortality through MBPS was 0.823. No patient with an MBPS < 3.7 mm died. The ROC curve for predicting combined mortality or readmission within the first month for MBPS was 0.698. CONCLUSIONS: Pupillometry may be a new, non-invasive, and simple tool to determine the status of SNS, help in the prognostic stratification of acute HF patients, and improve therapeutic management.

Stereotactic radiosurgery for the treatment of a distant recurrence of ependymoma on the optic nerve: illustrative case.

BACKGROUND: Ependymomas rarely disseminate to other central nervous system areas distant from the original site. Stereotactic radiosurgery (SRS) provides high control rates for recurring ependymomas. The treatment of optic nerve tumors carries high morbidity, but SRS is an acceptable option to manage these cases to reduce risks. OBSERVATIONS: The authors report the case of a 31-year-old male with a cervical spinal ependymoma who had a disseminated pattern of recurrence including the optic nerve after initial resection of the cervical lesion. The optic nerve tumor was treated with SRS, and the authors discuss the technical aspects of the treatment and its outcomes. At the last follow-up, the optic nerve tumor was controlled with SRS, and visual function was preserved. LESSONS: High-grade ependymomas such as the one in the presented case can have unpredictable patterns of recurrence. SRS provides excellent control of the distant recurring ependymoma with a low complication profile given the location of the tumor in this case.

Stereotactic radiosurgery for brain arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia.

OBJECTIVE: Brain arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HHT) present different characteristics from sporadic AVMs, and they have lower initial bleeding rates. Conservative management is usually preferred for the treatment of these lesions. In this case study, we present the largest series of HHT patients treated with stereotactic radiosurgery to date. METHODS: We identified eight patients with HHT and 14 AVMs. We retrospectively collected clinical, radiographic, and treatment characteristics of the patients and each AVM. RESULTS: Most patients in our sample presented with small AVMs. The median volume of these AVMs was 0.22 cm3 (IQR 0.08-0.59). Three out of eight patients presented with initial intracerebral hemorrhage (ICH). The majority of lesions had low (12/14) Spetzler-Martin grades (I-II). Median maximum and margin doses used for treatment were 36.2 (IQR 35.25-44.4) and 20 (IQR 18-22.5) Gy, respectively. The overall obliteration rate after SRS was 11/14, and the median time to obliteration across all 11 obliterated AVMs was 35.83 months (IQR, 17-39.99). Neurological status was favorable with all patients having a mRS of 0 or 1 at the last follow-up. Symptomatic radiation-induced changes (RIC) after SRS were low (7.1%), and there were no permanent RIC. CONCLUSIONS: Patients with HHT who present with multiple brain AVMs are generally well served by SRS. Obliteration can be achieved in the majority of HHT patients and with a low complication rate. In the current study, initial hemorrhage rates prior to SRS were noticeable which supports the decision to treat these AVMs. Future studies are needed to better address the role of SRS for HHT patients harboring ruptured and unruptured AVMs.

Physiological and molecular predictors of cycling sprint performance.

The study aimed to identify novel muscle phenotypic factors that could determine sprint performance using linear regression models including the lean mass of the lower extremities (LLM), myosin heavy chain composition (MHC), and proteins and enzymes implicated in glycolytic and aerobic energy generation (citrate synthase, OXPHOS proteins), oxygen transport and diffusion (myoglobin), ROS sensing (Nrf2/Keap1), antioxidant enzymes, and proteins implicated in calcium handling. For this purpose, body composition (dual-energy X-ray absorptiometry) and sprint performance (isokinetic 30-s Wingate test: peak and mean power output, Wpeak and Wmean ) were measured in young physically active adults (51 males and 10 females), from which a resting muscle biopsy was obtained from the musculus vastus lateralis. Although females had a higher percentage of MHC I, SERCA2, pSer16 /Thr17 -phospholamban, and Calsequestrin 2 protein expressions (all p < 0.05), and 18.4% lower phosphofructokinase 1 protein expression than males (p < 0.05), both sexes had similar sprint performance when it was normalized to body weight or LLM. Multiple regression analysis showed that Wpeak could be predicted from LLM, SDHB, Keap1, and MHC II % (R 2 = 0.62, p < 0.001), each variable contributing to explain 46.4%, 6.3%, 4.4%, and 4.3% of the variance in Wpeak , respectively. LLM and MHC II % explained 67.5% and 2.1% of the variance in Wmean , respectively (R 2 = 0.70, p < 0.001). The present investigation shows that SDHB and Keap1, in addition to MHC II %, are relevant determinants of peak power output during sprinting.

Solubility and Thermodynamic Parameters of H2S/CH4 in Ionic Liquids Determined by 1H NMR.

Natural gas remains an important global source of energy. Usually, sour gas from the well or refinery stream contains H2S among other contaminants that should be removed to fulfill permissible standards of use. Despite the use of different gas-liquid sour gas upgrading technologies, ionic liquids (ILs) have been recognized as promising materials to remove H2S from sour gas. However, data concerned with thermodynamic solution functions of H2S in ILs have scarcely been reported in the literature. In this work, solution 1H NMR spectroscopy was employed for quantifying H2S soluble in [BMIM][Cl] and for gaining a better understanding of the H2S-IL interaction. Experiments were carried out in a Young-Tap NMR tube containing a saturated solution of H2S/CH4/[BMIM][Cl] and recording spectra from 298 to 333 K. The thermodynamic solution functions, determined from the Van't Hoff equation, showed that solubility of the H2S in the [BMIM][Cl] is an exothermic gas-liquid physisorption process (ΔsolH° = -66.13 kJmol-1) with a negative entropy change (ΔsolS° = -168.19 JK-1 mol-1). 1H NMR spectra of the H2S/[BMIM][Cl] solution show a feature of strong solute-solvent interactions. However, solubility enthalpy is a fifth of the H-S bond energy value. Results from 1H NMR spectroscopy also agree with those from the bench dynamic experiments.

Social determinants of hypertensive disorders of pregnancy trends in Mexican municipalities.

OBJECTIVES: To analyze the hypertensive disorders of pregnancy (HDP) trends in the 2000-2020 period and its association with social determinants of health (SDH) in Mexican municipalities. STUDY DESIGN: This was a retrospective longitudinal study analyzing data from routine information systems on 21,493,076 hospital discharges due to maternal causes and SDH data of 2,439-2,450 municipalities between 2000 and 2020. MAIN OUTCOMES MEASURES: We used joinpoint regression models to analyze HDP trends and hybrid negative binomial regression models to examine the association between SDH and HDP rates at intra- and inter-municipality levels. RESULTS: HDP rate increased from 0.54 in 2000 to 2.42 cases per 100 live births in 2020 (annual average percent change of 7.7 %, 95 % CI 6.6-8.9). Municipalities with higher marginalization index had higher HDP rates (IRR 1.12, 95 % CI 1.01-1.24; 1.36, 95 % CI 1.25-1.47; 1.30, 95 % CI 1.23-1.37, and 1.06, 95 % CI 1.00-1.12, in 2000-2004, 2005-2009, 2010-2014, 2015-2020, respectively). Municipal increases in the percentage of population with high schooling were associated with decreases in HDP rates in 2000-2009. Meanwhile, the role of socioeconomic status at the state level was less consistent, yet the HDP rates were lower in most socially advantaged regions. CONCLUSION: During 21 years, HDP rates increased overall in Mexican municipalities, suggesting an increased maternal morbidity burden due to HDP. The association of municipal marginalization and socioeconomic level with HDP trends indicates a need to ensure equitable interventions to improve maternal health in Mexican municipalities.

Evaluation of the Abdala Vaccine: Antibody and Cellular Response to the RBD Domain of SARS-CoV-2.

Abdala is a recently released RBD protein subunit vaccine against SARS-CoV-2. A few countries, including Mexico, have adopted Abdala as a booster dose in their COVID-19 vaccination schemes. Despite that, most of the Mexican population has received full-scheme vaccination with platforms other than Abdala; little is known regarding Abdala's immunological features, such as its antibody production and T- and B-cell-specific response induction. This work aimed to study antibody production and the adaptive cellular response in the Mexican population that received the Abdala vaccine as a booster. We recruited 25 volunteers and evaluated their RBD-specific antibody production, T- and B-cell-activating profiles, and cytokine production. Our results showed that the Abdala vaccine increases the concentration of RBD IgG-specific antibodies. Regarding the cellular response, after challenging peripheral blood cultures with RBD, the plasmablast (CD19+CD27+CD38High) and transitional B-cell (CD19+CD21+CD38High) percentages increased significantly, while T cells showed an increased activated phenotype (CD3+CD4+CD25+CD69+ and CD3+CD4+CD25+HLA-DR+). Also, IL-2 and IFN-γ increased significantly in the supernatant of the RBD-stimulated cells. Our results suggest that Abdala vaccination, used as a booster, evokes antibody production and the activation of previously generated memory against the SARS-CoV-2 RBD domain.

Ginkgo biloba: Antioxidant Activity and In Silico Central Nervous System Potential.

Ginkgo biloba (GB) extracts have been used in clinical studies as an alternative therapy for Alzheimer's disease (AD), but the exact bioaction mechanism has not yet been elucidated. In this work, an in silico study on GB metabolites was carried out using SwissTargetPrediction to determine the proteins associated with AD. The resulting proteins, AChE, MAO-A, MAO-B, ß-secretase and γ-secretase, were studied by molecular docking, resulting in the finding that kaempferol, quercetin, and luteolin have multitarget potential against AD. These compounds also exhibit antioxidant activity towards reactive oxygen species (ROS), so antioxidant tests were performed on the extracts using the DPPH and ABTS techniques. The ethanol and ethyl acetate GB extracts showed an important inhibition percentage, higher than 80%, at a dose of 0.01 mg/mL. The effect of GB extracts on AD resulted in multitarget action through two pathways: firstly, inhibiting enzymes responsible for degrading neurotransmitters and forming amyloid plaques; secondly, decreasing ROS in the central nervous system (CNS), reducing its deterioration, and promoting the formation of amyloid plaques. The results of this work demonstrate the great potential of GB as a medicinal plant.

Cirugía de Ross en Chile: Tasa libre de reoperación y supervivencia global en una cohorte de más de 10 años de seguimiento

Antecedentes: El autoinjerto de válvula pulmonar (VP) u operación de Ross (OpR) tiene excelentes resultados a largo plazo. Es superior a otros tipos de reemplazo valvular en jóvenes adultos, aunque no el estándar de primera línea. Un tiempo quirúrgico prolongado o alta morbimortalidad son importantes preocupaciones. Objetivos: Establecer la morbimortalidad asociada a la OpR por un período >10 años, considerando el tiempo quirúrgico, tasa de reoperación y supervivencia global (SG). Métodos: Cohorte prospectiva (1996-2012), en seguimiento hasta agosto-2023. La SG fue estimada desde la OpR hasta la última consulta o deceso. Mediante regresión de Cox (Hazard Ratio, HR) se estimaron factores asociados a la SG. Resultados: La serie consta de 161 pacientes: 118 de etiología congénita (73.3%), 17 infecciosa (10.6%), 26 reumática (16.1%). La lesión fue estenótica en 79 (49.1%), insuficiencia en 40 (24.8%), mixta en 42 (26.1%). La OpR fue urgente en 11 (6.8%). The median time of ECC and the operation was 149 y 232 minutos, respectivamente. Veintisiete pacientes requirieron reoperación (16.8%). Con una mediana de 19.7 años (17.2-22.2), 23 pacientes fallecieron (14.3%): 1/23 asociado a OpR, 17/23 por causa cardiovascular y 5/23 por causas no cardiovasculares. La lesión mixta se asoció a mayor mortalidad (HR 3.07; IC 95% 1.11-8.47; p=.029). Conclusiones: La OpR es un procedimiento con baja morbimortalidad. La lesión mixta es un factor de riesgo independiente de mayor mortalidad. Sin embargo, la mediana de tiempo de CEC y quirúrgico es prolongado frente a otras técnicas de reemplazo valvular.

Background: Pulmonary valve (PV) autograftor reoperation or Ross surgery (RS), presents excellent long-term results. It is superior to other types of PV replacement in young adults, although it is not the first-line gold standard. A longer operative time or high morbidity and mortality rates are important concerns. Aim: To establish the morbidity and mortality associated with RS for >10 years, considering operative time, reoperation rate and overall survival (OS). Methods: Prospective cohort (1996-2012), with a follow-up until August/2023. The OS was estimated from RS to the last consultation/death. Factors associated to OS were estimated using Cox regression (Hazard Ratio, HR) Results: 161 patients were included: the etiology was congenital (118, 73%), infectious (17, 10.6%), and rheumatic (26,16.1%). The lesion was stenotic in 79 (49.1%), heart failure in 40 (24.8%), mixed in 42 (26.1%). RS was urgent in 11 (6.8%). Extracorporeal circulation (ECC) and operative times were 149 and 232 minutes, respectively. Twenty-seven patients required reoperation (16.8%). With a median follow up of 19.7 years (17.2-22.2), 23 patients died (14.3%): 1/23 associated with RS, 17/23 due to cardiovascular causes, and 5/23 due to non-cardiovascular causes. Mixed injury was associated with higher mortality (HR 3.07; 95% CI 1.11-8.47; p=.029). Conclusions: RS is a procedure with low morbidity and mortality. Mixed injury is an independent risk factor for increased mortality. However, the median ECC and operative times were higher compared to other valvular replacement techniques.

Geothermal food dehydrator system, operation and sensory analysis, and dehydrated pineapple quality.

Food dehydration is a preservation technique that guarantees its supply. Food like vegetables and fruits are traditionally dehydrated with natural gas or solar energy, however, this work demonstrates the feasibility of doing it with energy from a geothermal power plant in Nayarit, Mexico. Different species of pineapple (Miel, Cayenne, and Esmeralda) were dehydrated at different temperatures from 64 to 80°C and the safety of the product was subsequently verified, for these aerobic mesophiles (<230 ufc/g), total coliforms (<0.3 s.m.), molds and yeasts (<120 v.e.), and salmonella spp (Absent in 25 g), and results were obtained within the proposed specifications, which were generated taking as reference the national and international guidance standards. A sensory evaluation, a modified Flash Profile (mFP), was carried out with a group of judges trained in descriptive methodology, since a better consensus of responses was obtained, thus demonstrating the usability of mFP for food dehydration. The studies of pineapple allowed the evaluation of production with the DGA 200 technology, and the microbiological standards, as well as sensory and physicochemical parameters, were considering just to verify that product is suitable for human consumption. The technology is a system that takes advantage of the heat of the earth, with which it is possible to work 7 days a week or the entire pineapple season. Physicochemical changes caused by its dehydration with respect to the content of vitamin C, carbohydrates, and dietary fiber in the three species of dehydrated pineapple were measured. In the fresh samples, an average concentration of vitamin C 9 mg/100 g, carbohydrates 11.6 g sugar/100 g, and dietary fiber 0.96% were measured. The dehydrated samples presented an average value of vitamin C of 95 mg/100 g, carbohydrates 72.6 g sugar/100 g, and dietary fiber 8.6%, these results were similar to Mühlbauer and Müller, 2020, Drying atlas, drying kinetics and quality of agricultural products, Elsevier.

Variability of Vaccine Responsiveness in Young Children.

BACKGROUND: Variability in vaccine responsiveness among young children is poorly understood. METHODS: Nasopharyngeal secretions were collected in the first weeks of life for measurement of cytokines/chemokines seeking a biomarker, and blood samples collected at age one year to identify vaccine responsiveness status, defined as low vaccine responder (LVR), normal (NVR) and high (HVR), to test for vaccine antigen-induced immune memory, and for antigen presenting cell (APC) function. RESULTS: Significantly lower specific cytokine/chemokine levels as biosignatures, measurable in nasopharyngeal secretions at infant age 1-3 weeks old, predicted LVR status compared to NVR and HVR children. Antibiotic exposures were correlated with increased occurrence of LVR. At age 1 year old, LVRs had fewer CD4+ T-helper-1 and T-helper-2 memory cells responsive to specific vaccine antigens. APC responses observed among LVRs, both at rest and in response to TLR7/8 stimulation by R848 were suboptimal, suggesting that altered innate immunity may contribute to immune deficiency in LVRs. CONCLUSION: Cytokine biosignatures in the first weeks of life may predict vaccine responsiveness in children during the first year of life. Antibiotic exposure associates with LVR in children. CD4+ T-cell memory induction and APC deficiencies occur in LVR children.

Naturally-induced serum antibody levels in children to pneumococcal polysaccharide 15B that correlate with protection from nasopharyngeal colonization but anti-serotype 15B antibody has low functional cross-reactivity with serotype 15C.

BACKGROUND: Serotypes 15B and 15C have been added to new different pneumococcal-conjugate vaccines (PCV20 and V116, respectively). We determined a serum anti-15B antibody level that would be a correlate of protection (COP) against nasopharyngeal colonization and assessed functional cross-reactivity against serotype 15B and 15C in children following natural immunization. METHOD: IgG-antibody to serotype 15B polysaccharide was measured by ELISA in 341 sera from 6 to 36 month old children collected before, at the time of, and after pneumococcal colonization caused by serotypes 15B and 15C. 155 age-matched controls who had no detected colonization caused by serotype 15B or 15C strains were used as controls. A two-step method was used for construction of COP models: a generalized estimating equation followed by logistic-regression. Opsonophagocytic (OPA) assays assessed functional cross-reactivity between serotypes 15B and 15C. RESULTS: The derived COP for prevention of colonization was 1.18 µg/ml for serotype 15B and 0.63 µg/ml for serotype 15C, with a predictive probability of 80 %. Antibody levels did not correlate with OPA titers. 30 % of child samples, with moderate to high amounts of ELISA-measured antibody, showed no OPA titer against either serotype 15B or 15C. For remaining samples, very low or no functional cross-reactivity between serotypes 15B and 15C was measured. CONCLUSIONS: A COP for prevention of colonization in young children based on naturally-induced antibody levels was derived for serotypes 15B and 15C that differed. Antibody levels correlated poorly with OPA titers and low functional cross-reactivity between serotypes 15B and 15C in child sera was observed.

Antioxidant enzymes and Nrf2/Keap1 in human skeletal muscle: Influence of age, sex, adiposity and aerobic fitness.

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO2max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO2max, age and adiposity differences. Multiple regression analysis indicates that the VO2max in mL.kg LLM-1.min-1can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO2max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO2max and body fat percentage. Overweight and obesity were associated with increased pSer40-Nrf2, pSer40-Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO2max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise.