Workloads in Collegiate Women's Lacrosse Athletes During a Division II National Championship Season.

ABSTRACT: Sutton, PJ, Mumford, PW, and Sunderland, KL. Workloads in collegiate women's lacrosse athletes during a Division II national championship season. J Strength Cond Res 38(9): 1651-1657, 2024-A comprehensive examination of the external and internal workloads in collegiate women's lacrosse athletes has yet to be reported. Thus, the primary purpose of this study was to determine the absolute and relative external and internal training and game workloads of National Collegiate Athletic Association (NCAA) Division II women's lacrosse athletes throughout an entire season. Data from 19 Division II women's lacrosse athletes were analyzed, encompassing each training session and game across an entire competitive season (February-May). External workloads were assessed using a wearable global positioning system, whereas internal workloads were determined through heart rate (HR) variables and session rating of perceived exertion. Game days were associated with significantly ( p < 0.05) greater absolute external and internal workloads. However, when comparing workloads relative to session duration, relative workloads between training and games were no longer significant ( p > 0.05) for total distance, high-speed running (≥15 km·h -1 ), HR-derived training impulse, or caloric expenditure. Nonetheless, relative sprint distance (>19 km·h -1 ) was significantly lower during games, whereas high-intensity accelerations (>2 m·s -2 ) and decelerations (<-2 m·s -2 ) were significantly greater during training compared with games ( p < 0.05). Practical applications of these findings suggest that coaches can better prepare athletes for game day conditions by adjusting training plans to replicate the duration and intensity of games. Overall, this comprehensive examination of internal and external workloads provides valuable data for coaches and practitioners to support performance comparisons, rehabilitation protocols, and workload analyses in collegiate women's lacrosse athletes.

Effects of an external pneumatic compression device vs static compression garment on peripheral circulation and markers of sports performance and recovery.

PURPOSE: To identify the effects of a single 30 min partial lower leg external pneumatic compression (EPC) treatment compared to a static compression (SC) garment or a no treatment control (CTL) on markers of recovery and performance following a muscle damaging protocol. METHODS: Thirty healthy, active males (23 ± 3 years; 180.2 ± 9.0 cm; 81.6 ± 11.3 kg) performed 100 drop jumps from a 0.6 m box followed by a randomized, single 30 min treatment of either a partial lower leg EPC device worn below the knee and above the ankle (110 mmHg), SC garment (20-30 mmHg) covering the foot and calf just below the knee, or no treatment CTL, and then returned 24 and 48 h later. Participants were assessed for measures of muscle soreness, fatigue, hemodynamics, blood lactate, muscle thickness, circumferences, and performance assessments. RESULTS: The drop jump protocol significantly increased muscle soreness (p < 0.001), fatigue (p < 0.001), blood flow (p < 0.001), hemoglobin (p < 0.001), and muscle oxygen saturation (SMO2; p < 0.001). Countermovement jump and squat jump testing completed after treatment with either EPC, SC, or CTL revealed no differences for jump height between any condition. However, EPC treatment maintained consistent braking force and propulsive power measures across all timepoints for countermovement jump testing. EPC and SC treatment also led to better maintenance of squat jump performance for average relative propulsive force and power variables at 24 and 48 h compared to CTL. CONCLUSIONS: A single 30 min partial leg EPC treatment may lead to more consistent jump performance following a damaging bout of exercise.

Effect of valine on myotube insulin sensitivity and metabolism with and without insulin resistance.

Population data have consistently demonstrated a correlation between circulating branched-chain amino acids (BCAA) and insulin resistance. Most recently valine catabolite, 3-hydroxyisobutyrate, has emerged as a potential cause of BCAA-mediated insulin resistance; however, it is unclear if valine independently promotes insulin resistance. It is also unclear if excess valine influences the ability of cells to degrade BCAA. Therefore, this study investigated the effect of valine on muscle insulin signaling and related metabolism in vitro. C2C12 myotubes were treated with varying concentrations (0.5 mM-2 mM) of valine for up to 48 h. qRT-PCR and western blot were used to measure metabolic gene and protein expression, respectively. Insulin sensitivity (indicated by pAkt:Akt), metabolic gene and protein expression, and cell metabolism were also measured following valine treatment both with and without varying levels of insulin resistance. Mitochondrial and glycolytic metabolism were measured via oxygen consumption and extracellular acidification rate, respectively. Valine did not alter regulators of mitochondrial biogenesis or glycolysis; however, valine reduced branched-chain alpha-keto acid dehydrogenase a (Bckdha) mRNA (but not protein) expression which was exacerbated by insulin resistance. Valine treatment had no effect on pAkt:Akt following either acute or 48-h treatment, regardless of insulin stimulation or varying levels of insulin resistance. In conclusion, despite consistent population data demonstrating a relationship between circulating BCAA (and related metabolites) and insulin resistance, valine does not appear to independently alter insulin sensitivity or worsen insulin resistance in the myotube model of skeletal muscle.

Intramuscular phosphagen status and the relationship to muscle performance across the age spectrum.

PURPOSE: To examine age-related differences in intramuscular concentrations of adenosine triphosphate (ATP), free creatine (FCr), phosphocreatine (PCr) and total creatine (TCr) and if these differences were related to muscle performance. METHODS: Forty-two healthy, non-sedentary, males between 20 and 76 years provided muscle samples to determine [ATP], [FCr], [PCr], and [TCr]. Maximal strength and endurance were assessed and correlated with intramuscular variables. RESULTS: Intramuscular [ATP] decreased by 13.5% (p = 0.013) in the older cohort (18.0 ± 0.6 mmol/kg dry wt) vs. the young cohort (20.8 ± 0.9 mmol/kg dry wt) and was significantly correlated to age (r = -0.38, p = 0.008). No other differences were observed between age groups for intramuscular [PCr], [FCr], [TCr], or [PCr]:[TCr] (p > 0.05). The older cohort consumed significantly less (p < 0.05) dietary protein when compared to the young cohort. Bivariate correlations were found for intramuscular [ATP] and lower body 1RM (r = 0.24, p = 0.066), leg press volume and free creatine (r = 0.325, p = 0.036) and leg press repetitions and free creatine (r = 0.373, p = 0.015). Partial correlations controlling for age eliminated the relationship between [ATP] and 1RM while intramuscular free creatine and leg press repetitions remained significant (p < 0.05) and leg press volume approached significance (p = 0.095). CONCLUSION: These results expand upon previous observations indicative of age-related reductions in intramuscular [ATP] and dietary protein intake. The lack of change in other intramuscular PCr system markers are suggestive of dysfunctions at the mitochondrial level while the impact of neuromuscular changes, lean mass cross-sectional area and differences in physical activity are also important.

Milk or Kefir, in Comparison to Water, Do Not Enhance Running Time-Trial Performance in Endurance Master Athletes.

This study compared flavored kefir (KFR) and flavored milk (MLK) as a recovery drink in endurance master athletes. Using a randomized, placebo-controlled, non-blinded crossover design, 11 males and females completed three testing visits whilst acutely ingesting either KFR, MLK, or water as a placebo (PLA). KFR supplementation occurred for 14 days before the KFR-testing day, followed by a 3-week washout period. Testing visits consisted of an exhausting-exercise (EE) bout, a 4-h rest period where additional carbohydrate feeding was provided, and a treadmill 5 km time trial (TT). The Gastrointestinal Symptom Rating Scale (GSRS) survey was assessed at four timepoints. Blood was collected at baseline and after the TT and was analyzed for I-FABP levels. No significant difference (PLA: 33:39.1 ± 6:29.0 min, KFR: 33:41.1 ± 5:44.4 min, and MLK: 33:36.2 ± 6:40.5 min, p = 0.99) was found between the groups in TT performance. The KFR GSRS total score was significantly lower than the PLA after EE (p = 0.005). No differences in I-FABP were observed between conditions. In conclusion, acute KFR supplementation did not impact TT performance or I-FABP levels but may have reduced subjective GI symptoms surrounding exercise when compared to MLK or PLA.

Aging and sequential resistance exercise bout effects on housekeeping gene messenger RNA expression in human skeletal muscle.

The purpose of this study was to investigate how age and 1 week of conventional resistance exercise affects commonly used housekeeping gene (HKG) messenger RNAs (mRNAs) in skeletal muscle. Ten college-aged (18-25 years) and 10 older (60-76 years) men completed 3 lower-body resistance exercise bouts on Monday, Wednesday, and Friday, and muscle samples were obtained before bout 1 (T1), 48 hours after the first (T2) and second bouts (T3), and 24 hours after the third bout (T4). Raw Ct values indicated that ß-actin and cyclophilin were more highly expressed in older vs. younger males (p < 0.01) at T1. When normalizing each HKG mRNA to the other 4 HKG mRNAs, CYC increased at T3 and glyceraldehyde-3-phosphate dehydrogenase decreased at T2 (p < 0.05) in younger men. This is one of the few studies to suggest that explicit HKG mRNAs should be used depending upon age group and resistance exercise intervention.

Naturally Bicarbonated Water Supplementation Does Not Improve Anaerobic Cycling Performance or Blood Gas Parameters in Active Men and Women.

The completion of high-intensity exercise results in robust perturbations to physiologic homeostasis, challenging the body's natural buffering systems to mitigate the accumulation of metabolic by-products. Supplementation with bicarbonate has previously been used to offset metabolic acidosis, leading to improvements in anaerobic exercise performance. PURPOSE: The purpose of this study was to investigate the presence of ergogenic properties in naturally occurring low-dose bicarbonated water and their effects on anaerobic cycling performance and blood gas kinetics in recreationally active men and women. METHODS: Thirty-nine healthy, recreationally active men and women (28.1 ± 8.0 years, 169.8 ± 11.7 cm, 68.9 ± 10.8 kg, 20.1 ± 7.9% fat, V˙O2peak: 42.8 ± 7.6 mL/kg/min) completed two separate testing sessions consisting of 15 cycling sprints (10 s sprint, 20 s active rest) against 7.5% of their body mass. Using a randomized, double-blind, placebo-controlled, parallel group study design, study participants consumed a 10 mL/kg dose of either spring water (SW) or bicarbonated mineral water (BMW) (delivering ~3 g/day of bicarbonate) for 7 days. Venous blood was collected before, immediately after, and 5 and 10 min after the sprint protocol and was analyzed for lactate and a series of blood gas components. After the completion of 15 cycling sprints, averages of peak and mean power for bouts 1-5, 6-10, and 11-15, along with total work for the entire cycling protocol, were calculated. All performance and blood gas parameters were analyzed using a mixed-factorial ANOVA. RESULTS: pH was found to be significantly higher in the BMW group immediately after (7.17 ± 0.09 vs. 7.20 ± 0.11; p = 0.05) and 10 min post exercise (7.21 ± 0.11 vs. 7.24 ± 0.09; p = 0.04). A similar pattern of change was observed 5 min post exercise wherein pH levels in the SW group were lower than those observed in the BMW group; however, this difference did not achieve statistical significance (p = 0.09). A statistical trend (p = 0.06) was observed wherein lactate in the BMW group tended to be lower than in the SW group 5 min post exercise. No significant main effect for time (p > 0.05) or group × time interactions (p > 0.05) for the total work, average values of peak power, or average values of mean power were observed, indicating performance was unchanged. CONCLUSION: One week of consuming water with increased bicarbonate (10 mL/kg; ~3 g/day bicarbonate) showed no effect on anaerobic cycling performance. BMW decreased blood lactate concentrations 5 min after exercise and increased blood pH immediately and 10 min after exercise.

Electrophoretic separation of myosin heavy chain isoforms using a modified mini gel system.

The electrophoretic separation of myosin heavy chain isoforms from muscle biopsy homogenates has been widely practiced in the field of exercise physiology to examine how intrinsic (i.e., aging) and extrinsic (i.e., training) factors affect muscle phenotype. In the past, various research groups have used large and mini polyacrylamide gel systems to perform this delicate methodology. As technology has progressed, additional gel formats have been introduced, but available methodologies appear to be lacking. In this investigation, we successfully separated 3 distinct myosin heavy chain isoforms from various muscle samples using a modified mini gel system that can load up to 26 samples per gel. This article will outline our allocated protocol and discuss potential troubleshooting considerations for other researchers performing this intricate methodology. The outlined methodology has resulted in an ability to clearly resolute 3 distinct bands at molecular weights attributed to the myosin heavy chain isoforms in human skeletal muscle at a wide range of human ages (20-78 years). As additional technologies become available, the need to modify and adapt existing electrophoretic protocols for myosin heavy chain isoform separation and other protocols will continue to be evident.

SlicerHeart: An open-source computing platform for cardiac image analysis and modeling.

Cardiovascular disease is a significant cause of morbidity and mortality in the developed world. 3D imaging of the heart's structure is critical to the understanding and treatment of cardiovascular disease. However, open-source tools for image analysis of cardiac images, particularly 3D echocardiographic (3DE) data, are limited. We describe the rationale, development, implementation, and application of SlicerHeart, a cardiac-focused toolkit for image analysis built upon 3D Slicer, an open-source image computing platform. We designed and implemented multiple Python scripted modules within 3D Slicer to import, register, and view 3DE data, including new code to volume render and crop 3DE. In addition, we developed dedicated workflows for the modeling and quantitative analysis of multi-modality image-derived heart models, including heart valves. Finally, we created and integrated new functionality to facilitate the planning of cardiac interventions and surgery. We demonstrate application of SlicerHeart to a diverse range of cardiovascular modeling and simulation including volume rendering of 3DE images, mitral valve modeling, transcatheter device modeling, and planning of complex surgical intervention such as cardiac baffle creation. SlicerHeart is an evolving open-source image processing platform based on 3D Slicer initiated to support the investigation and treatment of congenital heart disease. The technology in SlicerHeart provides a robust foundation for 3D image-based investigation in cardiovascular medicine.

Anatomically curated segmentation of human subcortical structures in high resolution magnetic resonance imaging: An open science approach.

Magnetic resonance imaging (MRI)-based brain segmentation has recently been revolutionized by deep learning methods. These methods use large numbers of annotated segmentations to train algorithms that have the potential to perform brain segmentations reliably and quickly. However, training data for these algorithms are frequently obtained from automated brain segmentation systems, which may contain inaccurate neuroanatomy. Thus, the neuroimaging community would benefit from an open source database of high quality, neuroanatomically curated and manually edited MRI brain images, as well as the publicly available tools and detailed procedures for generating these curated data. Manual segmentation approaches are regarded as the gold standard for brain segmentation and parcellation. These approaches underpin the construction of neuroanatomically accurate human brain atlases. In addition, neuroanatomically precise definitions of MRI-based regions of interest (ROIs) derived from manual brain segmentation are essential for accuracy in structural connectivity studies and in surgical planning for procedures such as deep brain stimulation. However, manual segmentation procedures are time and labor intensive, and not practical in studies utilizing very large datasets, large cohorts, or multimodal imaging. Automated segmentation methods were developed to overcome these issues, and provide high data throughput, increased reliability, and multimodal imaging capability. These methods utilize manually labeled brain atlases to automatically parcellate the brain into different ROIs, but do not have the anatomical accuracy of skilled manual segmentation approaches. In the present study, we developed a custom software module for manual editing of brain structures in the freely available 3D Slicer software platform that employs principles and tools based on pioneering work from the Center for Morphometric Analysis (CMA) at Massachusetts General Hospital. We used these novel 3D Slicer segmentation tools and techniques in conjunction with well-established neuroanatomical definitions of subcortical brain structures to manually segment 50 high resolution T1w MRI brains from the Human Connectome Project (HCP) Young Adult database. The structural definitions used herein are associated with specific neuroanatomical ontologies to systematically interrelate histological and MRI-based morphometric definitions. The resulting brain datasets are publicly available and will provide the basis for a larger database of anatomically curated brains as an open science resource.

Metabolic impact of feeding prior to a 60-min bout of moderate-intensity exercise in females in a fasted state.

Background: The metabolic impact of pre-exercise feeding of protein or carbohydrate on fat oxidation and energy expenditure rates, especially, in females, is poorly understood. Methods: Recreationally active females (n = 15, 32 ± 10 years, 164.8 ± 5.6 cm, 63.5 ± 9.3 kg, 23.4 ± 3.2 kg/m2) completed four testing sessions in a randomized, double-blind, crossover fashion after fasting overnight. Participants ingested isovolumetric and isoenergetic solutions containing either 25 g of whey protein, casein protein, carbohydrate (CHO), or a non-caloric placebo (PLA). Participants then completed 60 min of treadmill exercise at 15% below ventilatory threshold 30 min after ingestion. Respiratory exchange ratio (RER) was evaluated throughout exercise and resting energy expenditure (REE) was assessed pre-exercise, and 0-, 60-, and 120-min post-exercise. Results: A significant condition x time interaction was observed for RER (p = 0.008) during exercise, with CHO exhibiting higher RER values (vs. PLA) at four time points. A significant main effect for condition was observed for carbohydrate (p = 0.001) and fat (p = 0.02) oxidation rates during exercise, with fat oxidation rates being higher in PLA vs. CHO (p = 0.01). When total fat oxidized was calculated across the entire exercise bout, a significant main effect for condition was observed (p = 0.01), with PLA being greater than CHO (p = 0.04). A significant condition x time interaction (p = 0.02) was found for both absolute and normalized REE, with casein and whey protein having significantly higher values than CHO (p < 0.05) immediately post-exercise. Conclusion: When compared to a fasted control (PLA), consuming CHO, but not protein, decreased total fat oxidation prior to a 60-min bout of moderate-intensity exercise in females.

VO2max and ventilatory threshold of trained cyclists are not affected by 28-day L-arginine supplementation.

The ergogenic effect of L-arginine on an endurance-trained population is not well studied. The few studies that have investigated L-arginine on this population have not been conducted in a laboratory setting or measured aerobic variables. The purpose of the current study is to determine if 28 days of L-arginine supplementation in trained male cyclists affects VO2max and ventilatory threshold (VT). Eighteen (18) endurance-trained male cyclists (mean ± SD, age: 36.3 ± 7.9 years; height: 182.4 ± 4.6 cm; and body mass: 79.5 ± 4.7 kg) performed a graded exercise test (GXT; 50 W + 25 W·min) before and after 28 days of supplementation with L-arginine (ARG; 2 × 6 g·d) or placebo (PLA; cornstarch). The GXT was conducted on the subject's own bicycle using the RacerMate CompuTrainer (Seattle, WA, USA). VO2 was continuously recorded using the ParvoMedics TrueOne 2400 metabolic cart (Salt Lake City, UT, USA) and VT was established by plotting the ventilatory equivalent for O2 (VE/VO2) and the ventilatory equivalent for CO2 (VE/VCO2) and identifying the point at which VE/VO2 increases with no substantial changes in VE/VCO2. L-arginine supplementation had no effect from initial VO2max (PL, 58.7 ± 7.1 ml·kg·min; ARG, 63.5 ± 7.3 ml·kg·min) to postsupplement VO2max (PL, 58.9 ± 6.0 ml·kg·min; ARG, 63.2 ± 7.2 ml·kg·min). Also, no effect was seen from initial VT (PL, 75.7 ± 4.6% VO2max; ARG, 76.0 ± 5.3% VO2max) to postsupplement VT (PL, 74.3 ± 8.1% VO2max; ARG, 74.2 ± 6.4% VO2max). These results indicate that L-arginine does not impact VO2max or VT in trained male cyclists.

Megalin and androgen receptor gene expression in young and old human skeletal muscle before and after three sequential exercise bouts.

Androgen signaling occurs primarily via the androgen receptor. Megalin, a low-density lipoprotein endocytic receptor located in various mammalian tissues, has been recently shown to facilitate sex hormone­binding globulin (SHBG) steroid complexes across cell membranes. The purpose of this investigation is to determine if the megalin gene is expressed in human skeletal muscle and if present to determine how megalin and androgen receptor mRNA expression change in response to sequential exercise bouts with respect to aging. Ten younger (age: 18-25 years) and 10 older (age: 60-75 years) men completed 3 workouts (M, W, F) each consisting of 9 sets of lower-body exercises with 10 repetitions per set at 80% 1 repetition maximum. Vastus lateralis muscle biopsies were extracted at baseline (T1), 48 hours after workout 1 (T2) and 2 (T3), and 24 hours after workout 3 (T4), and blood samples were collected before and 5 minutes after each workout. Muscle was analyzed for megalin and androgen receptor expression using gene-specific primers and SYBR green chemistry, and blood was analyzed for serum testosterone, SHBG, and the free androgen index. Megalin was expressed in both young and old subjects across all time points, although no between- or within-group mean differences were detected at any time point. Androgen receptor was expressed higher in young men at all time points compared to in old men (p < 0.05), and a significant correlation (p < 0.05; r = 0.506) was found between serum testosterone and androgen receptor after workout 1. Based on our data, the gene coding for megalin is expressed inside skeletal muscle, but its role, if any, in steroid cellular transport cannot be determined. This finding could lay the groundwork for more mechanistic investigations to better delineate its functional role and its potential as a therapeutic adjunct for androgen-related disorders in healthy and aged populations.

The combined effects of exercise and ingestion of a meal replacement in conjunction with a weight loss supplement on body composition and fitness parameters in college-aged men and women.

This study was performed to evaluate the combined effect of a meal replacement and an alleged weight loss supplement (WLS) on body composition, fitness parameters, and clinical health in moderately overweight college-aged men and women. Body mass, bench press 1 repetition maximum (1RM), leg press 1RM, body composition, V(O2)max, fasting glucose (GLU), and lipid panels were evaluated before (T1) and after (T2) 8 weeks of combined resistance training (RT) and cardiovascular training (CVT). After T1, subjects were randomly assigned in a double-blind fashion to either the WLS (6 men, 7 women; 21 ± 5 years, 168 ± 8 cm, 75.4 ± 12.7 kg, 31.6 ± 7.7%BFAT) or placebo (PLA: 6 men, 6 women; 22 ± 4 years, 174 ± 9 cm, 84.1 ± 8.8 kg, 30.2 ± 5.6%BFAT) group. Both groups performed 3 d · wk(-1) of combined progressive RT (2 × 12 reps of 8 exercises at 75-80% 1RM) and CVT (30 minutes on a cycle ergometer at 70-85% heart rate reserve). Subjects consumed 4 capsules per day and a once-daily meal replacement throughout the protocol. Percent body fat, bench press 1RM, and leg press 1RM significantly improved (p < 0.05) in both groups. Blood GLU (G × T; p = 0.048) improved in WLS and systolic blood pressure (SBP) approached significance (G × T; p = 0.06) in the WLS group. Follow-up analysis of SBP revealed a significant within-group decrease in the WLS group, whereas no within-group changes were found for either group for GLU. Practically speaking, daily supplementation with a meal replacement and a thrice weekly exercise program can increase fitness levels and improve body composition, whereas adding a thermogenic substance provides no additional benefit over fitness or body composition changes but may favorably alter serum markers of clinical health.

IGF-1 splice variant and IGF-1 peptide expression patterns in young and old human skeletal muscle prior to and following sequential exercise bouts.

Genes and proteins involved in insulin-like growth factor (IGF)-1 signaling are thought to be differentially expressed in older versus younger mammalian skeletal muscle following acute exercise. The purpose of this study was to examine how multiple bouts of conventional resistance training meant to elicit hypertrophy affect the mRNA expression of IGF-1EA and IGF-1EC (MGF) as well as the expression of total IGF-1 peptides in human skeletal muscle. Ten younger (18-25 years) and 10 older (60-75 years) males completed three sequential workouts (M, W, F) consisting of nine sets of lower body exercises with ten repetitions per set at an intensity of 80% of one repetition maximum. Vastus lateralis muscle biopsies were collected prior to intervention (T1), 48 h following workout 1 (T2), 48 h following workout 2 (T3), and 24 h following workout 3 (T4). RT-PCR was performed to assess baseline and changes in MGF and IGF-IEA mRNA. Samples were also assayed for total muscle IGF-1 peptides using ELISA-based methods. There were no baseline differences in MGF or IGF-1EA mRNA expression and IGF-1 peptides between age groups. Interestingly, MGF expression increased at T2-T4 in the older group relative to baseline values (p < 0.05), albeit muscle IGF-1EA mRNA and IGF-1 peptides remained stably expressed throughout the intervention in both age groups. Repeated conventional exercise bouts resulted in a summative increase in MGF mRNA expression only in older individuals which is contrary to previous research examining this gene at different post-exercise time points, albeit the physiological consequences of these findings remain unknown.

Uncarboxylated osteocalcin decreases insulin-stimulated glucose uptake without affecting insulin signaling and regulators of mitochondrial biogenesis in myotubes.

Uncarboxylated osteocalcin (uOC) is a circulating bone matrix protein, which has previously been shown to regulate glucose uptake and systemic metabolism. However, the cellular mechanism by which uOC acts has yet to be elucidated. C2C12 mouse myotubes were treated for 72 h with uOC (1-100 ng/mL). Cellular metabolism was analyzed using oxygen consumption and extracellular acidification rate. Metabolic gene and protein expression were measured via quantitative real-time polymerase chain reaction and Western blot, respectively. Additionally, C2C12 myotubes were treated with 10 ng/mL uOC to examine glucose uptake and activation of insulin signaling with or without insulin resistance. Finally, cellular lipid content was measured via Oil Red O and Nile Red staining. uOC treatment resulted in dose-dependent alterations of oxygen consumption with little effect on regulators of mitochondrial metabolism. Basal expression of regulators of glucose uptake were unaffected by uOC treatment. However, insulin-stimulated glucose uptake was blunted by uOC treatment with no concurrent alterations in insulin signaling. While chronic insulin treatment resulted in suppressed activation of Akt, concurrent uOC treatment was unable to prevent these detrimental effects on insulin signaling. uOC treatment had no effect on markers of lipogenesis and cellular lipid content. These findings suggest that 72-h uOC treatment may alter oxygen consumption without effect on regulators of mitochondrial biogenesis. Additionally, uOC treatment suppressed insulin-stimulated glucose uptake in cultured myotubes but had little effect on insulin signaling or regulators of cellular metabolism and was unable to mitigate insulin resistance.

Automatic Spine Ultrasound Segmentation for Scoliosis Visualization and Measurement.

OBJECTIVE: Integrate tracked ultrasound and AI methods to provide a safer and more accessible alternative to X-ray for scoliosis measurement. We propose automatic ultrasound segmentation for 3-dimensional spine visualization and scoliosis measurement to address difficulties in using ultrasound for spine imaging. METHODS: We trained a convolutional neural network for spine segmentation on ultrasound scans using data from eight healthy adult volunteers. We tested the trained network on eight pediatric patients. We evaluated image segmentation and 3-dimensional volume reconstruction for scoliosis measurement. RESULTS: As expected, fuzzy segmentation metrics reduced when trained networks were translated from healthy volunteers to patients. Recall decreased from 0.72 to 0.64 (8.2% decrease), and precision from 0.31 to 0.27 (3.7% decrease). However, after finding optimal thresholds for prediction maps, binary segmentation metrics performed better on patient data. Recall decreased from 0.98 to 0.97 (1.6% decrease), and precision from 0.10 to 0.06 (4.5% decrease). Segmentation prediction maps were reconstructed to 3-dimensional volumes and scoliosis was measured in all patients. Measurement in these reconstructions took less than 1 minute and had a maximum error of 2.2° compared to X-ray. CONCLUSION: automatic spine segmentation makes scoliosis measurement both efficient and accurate in tracked ultrasound scans. SIGNIFICANCE: Automatic segmentation may overcome the limitations of tracked ultrasound that so far prevented its use as an alternative of X-ray in scoliosis measurement.

Actions of chronic physiological 3-hydroxyisobuterate treatment on mitochondrial metabolism and insulin signaling in myotubes.

Branched-chain amino acids (BCAAs) are essential in the diet and may provide benefit for those who partake in regular physical activity and resistance training, yet circulating BCAAs have been repeatedly shown to correlate with severity of insulin resistance in obese/diseased populations. Recently, the valine catabolite 3-hydroxyisobuterate (3HIB) was shown to promote insulin resistance in skeletal muscle by increasing lipid content in vivo. The purpose of this study was to investigate the mechanistic effects of 3HIB on skeletal muscle insulin signaling, metabolism, and related gene expression in vitro. Given these previous observations, we hypothesized that 3HIB would depress skeletal muscle metabolism and insulin sensitivity. C2C12 myotubes were treated with 3HIB for up to 48 hours using both physiological (25-100 µmol/L) and supraphysiological (5 mmol/L) concentrations. Metabolic gene expression was measured via quantitative real-time polymerase chain reaction, mitochondrial metabolism was measured via O2 consumption, and glycolytic metabolism was quantified using extracellular acidification rate. Western blot was used to assess insulin sensitivity following insulin stimulation (indicated by phospho-AKT expression). 3HIB did not alter expressional indicators of mitochondrial biogenesis, glycolysis, BCAA catabolism, or lipogenesis. Chronic physiological 3HIB treatment significantly increased peak oxygen consumption, whereas supraphysiological 3HIB treatment suppressed basal and peak mitochondrial and glycolytic metabolism. Both physiological and supraphysiological 3HIB reduced pAkt expression during insulin stimulation. These findings suggest that 3HIB may reduce muscle insulin sensitivity in cultured myotubes, supporting a potentially causal role of 3HIB in the development of insulin resistance in highly metabolic cell types.

Leucine, Palmitate, or Leucine/Palmitate Cotreatment Enhances Myotube Lipid Content and Oxidative Preference.

Branched-chain amino acids (BCAA) such as leucine stimulate favorable metabolic processes involved in lean tissue preservation and skeletal muscle metabolism. However, higher levels of circulating BCAA correlate with severity of metabolic disease (including diabetes/insulin resistance), and may result from dysregulated BCAA catabolism. Past observations have demonstrated potential interaction between BCAA and dietary fat; however, much of this relationship remains underexplored. This study investigated the effect of leucine both with and without palmitate on oxidative and glycolytic metabolism, as well as indicators of BCAA catabolism using cultured skeletal muscle cells. Specifically, C2C12 myotubes were treated with or without varying concentrations of leucine both with and without palmitate for 24 h. Leucine treatment significantly elevated mRNA expression of metabolic regulators including peroxisome proliferator-activated receptor-gamma coactivator 1-alpha versus leucine with concurrent palmitate treatment. Interestingly, leucine-only, palmitate-only, and leucine with palmitate all significantly increased cellular lipid content, which translated into significantly increased oxidative capacity under substrate-limited conditions. However, upon the addition of excess substrate and carnitine, discrepancies in peak metabolic capacities between various treatments were no longer observed, suggesting leucine, palmitate, or the combination thereof causes a shift in metabolic preference from glycolytic to oxidative. These data also suggest leucine's effect on mitochondrial metabolism may result in part from increased lipid stores in addition to other previously documented pathways.