IL-6 signaling in acute exercise and chronic training: Potential consequences for health and athletic performance.

The cytokine interleukin-6 (IL-6) is involved in a diverse set of physiological processes. Traditionally, IL-6 has been thought of in terms of its inflammatory actions during the acute phase response and in chronic conditions such as rheumatoid arthritis and obesity. However, IL-6 is also an important signaling molecule during exercise, being acutely released from working muscle fibers with increased exercise duration, intensity, and muscle glycogen depletion. In this context, IL-6 enables muscle-organ crosstalk, facilitating a coordinated response to help maintain muscle energy homeostasis, while also having anti-inflammatory actions. The range of actions of IL-6 can be explained by its dichotomous signaling pathways. Classical signaling involves IL-6 binding to a cell-surface receptor (mbIL-6R; present on only a small number of cell types) and is the predominant signaling mechanism during exercise. Trans-signaling involves IL-6 binding to a soluble version of its receptor (sIL-6R), with the resulting complex having a much greater half-life and the ability to signal in all cell types. Trans-signaling drives the inflammatory actions of IL-6 and is the predominant pathway in disease. A single nucleotide polymorphism (rs2228145) on the IL-6R gene can modify the classical/trans-signaling balance through increasing the levels of sIL-6R. This SNP has clinical significance, having been linked to inflammatory conditions such as rheumatoid arthritis and type 1 diabetes, as well as to the severity of symptoms experienced with COVID-19. This review will describe how acute exercise, chronic training and the rs2228145 SNP can modify the IL-6 signaling pathway and the consequent implications for health and athletic performance.

Attrition and reenlistment in the Army: Using the Tailored Adaptive Personality Assessment System (TAPAS) to improve retention.

Attrition and reenlistment are critical outcomes that continually shape the Army's workforce. However, relatively little is known about factors that reliably predict which Soldiers will ultimately complete their first term of service or reenlist after their first term has concluded. The present study evaluated the efficacy of a noncognitive measure, the Tailored Adaptive Personality Assessment System (TAPAS), as well as a traditional cognitive test, the Armed Forces Qualification Test (AFQT), as predictors of attrition and reenlistment. Specific categories of attrition were examined based on the reasons Soldiers separated from the Army, both during training and while the Soldiers were in their units. Additionally, analyses were conducted to model attrition over time, and reenlistment was examined both Army-wide and for specific MOS. The paper concludes with a discussion of the findings and needs for future research concerning the potential value of cognitive and noncognitive measures for better understanding and predicting Army attrition and reenlistment.

Improved recovery of human islets from young donor pancreases utilizing increased protease dose to collagenase for digesting peri-islet extracellular matrix.

Human islet isolation from young donor pancreases (YDP) utilizing the current purified standard dose of collagenase-protease enzyme mixtures often results in the release of a high percentage of mantled islets. Mantled islets are those surrounded by exocrine tissue and are difficult to purify by density gradient centrifugation, leading to poor islet recovery. Based on difference in extracellular matrix, and total collagen content between YDP and old donor pancreas (ODP, > 35 Y) led us to compare results from islet isolation using increased collagenase combination (ICC) or increased protease combination (IPC), to the standard enzyme combination (SEC) in a "trisected" pancreas model to overcome the donor-to-donor variability. These results showed a reduced percentage of mantled islets (17% ± 7.5%) and higher postpurification islet recovery (83.8% ± 5.6%) with IPC. Furthermore, these results were confirmed in 13 consecutive whole pancreas islet isolations utilizing IPC from VitaCyte, Roche, or SERVA collagenase-protease enzyme mixtures. Results obtained from in vitro and in vivo islet functional assessment indicated that islets isolated using IPC retained normal islet morphology, insulin secretion, and the ability to reverse diabetes after transplantation in diabetic nude mice. This is the first report utilizing trisected pancreas to assess the effectiveness of different enzyme combinations to improve islet recovery from young donor pancreases.

Lower-Limb Stiffness and Maximal Sprint Speed in 11-16-Year-Old Boys.

Meyers, RW, Moeskops, S, Oliver, JL, Hughes, MG, Cronin, JB, and Lloyd, RS. Lower-limb stiffness and maximal sprint speed in 11-16-year-old boys. J Strength Cond Res 33(7): 1987-1995, 2019-The purpose of the study was to examine the relationship between vertical stiffness, leg stiffness, and maximal sprint speed in a large cohort of 11-16-year-old boys. Three-hundred thirty-six boys undertook a 30-m sprint test using a floor-level optical measurement system, positioned in the final 15-m section. Measures of speed, step length, step frequency, contact time, and flight time were directly measured while force, displacement, vertical stiffness, and leg stiffness, were modeled from contact and flight times, from the 2 fastest consecutive steps for each participant over 2 trials. All force, displacement, and stiffness variables were significantly correlated with maximal sprint speed (p ≤ 0.05). Relative vertical stiffness had a very large (r > 0.7) relationship with sprint speed, whereas vertical center of mass displacement, absolute vertical stiffness, relative peak force, and maximal leg spring displacement had large (r > 0.5) relationships. Relative vertical stiffness and relative peak force did not significantly change with advancing age (p > 0.05), but together with maximal leg spring displacement accounted for 96% of the variance in maximal speed. It seems that relative vertical stiffness and relative peak force are important determinants of sprint speed in boys aged 11-16 years, but are qualities that may need to be trained because of no apparent increases from natural development. Practitioners may wish to use training modalities such as plyometrics and resistance training to enable adaptation to these qualities because of their importance as predictors of speed in youth.

Beneficial effect of recombinant rC1rC2 collagenases on human islet function: Efficacy of low-dose enzymes on pancreas digestion and yield.

A high number of human islets can be isolated by using modern purified tissue dissociation enzymes; however, this requires the use of >20 Wunsch units (WU)/g of pancreas for digestion. Attempts to reduce this dose have resulted in pancreas underdigestion and poor islet recovery but improved islet function. In this study, we achieved a high number of functional islets using a low dose of recombinant collagenase enzyme mixture (RCEM-1200 WU rC2 and 10 million collagen-degrading activity [CDA] U of rC1 containing about 209 mg of collagenase to digest a 100-g pancreas). The collagenase dose used in these isolations is about 42% of the natural collagenase enzyme mixture (NCEM) dose commonly used to digest a 100-g pancreas. Low-dose RCEM was efficient in digesting entire pancreases to obtain higher yield (5535 ± 830 and 2582 ± 925 islet equivalent/g, P < .05) and less undigested tissue (16.7 ± 5% and 37.8 ± 3%, P < .05) compared with low-dose NCEM (12WU/g). Additionally, low-dose RCEM islets retained better morphology (confirmed with scanning electron microscopy) and higher in vitro basal insulin release (2391 ± 1342 and 1778 ± 978 µU/mL; P < .05) compared with standard-dose NCEM. Nude mouse bioassay demonstrated better islet function for low-dose RCEM (area under the curve [AUC] 24 968) compared with low-dose (AUC-38 225) or standard-dose NCEM (AUC-38 685), P < .05. This is the first report indicating that islet function can be improved by using low-dose rC1rC2 (RCEM).

Asymmetry During Maximal Sprint Performance in 11- to 16-Year-Old Boys.

PURPOSE: The aim of this study was to examine the influence of age and maturation upon magnitude of asymmetry in the force, stiffness and the spatiotemporal determinants of maximal sprint speed in a large cohort of boys. METHODS: 344 boys between the ages of 11 and 16 years completed an anthropometric assessment and a 35 m sprint test, during which sprint performance was recorded via a ground-level optical measurement system. Maximal sprint velocity, as well as asymmetry in spatiotemporal variables, modeled force and stiffness data were established for each participant. For analysis, participants were grouped into chronological age, maturation and percentile groups. RESULTS: The range of mean asymmetry across age groups and variables was 2.3-12.6%. The magnitude of asymmetry in all the sprint variables was not significantly different across age and maturation groups (p > .05), except relative leg stiffness (p < .05). No strong relationships between asymmetry in sprint variables and maximal sprint velocity were evident (rs < .39). CONCLUSION: These results provide a novel benchmark for the expected magnitude of asymmetry in a large cohort of uninjured boys during maximal sprint performance. Asymmetry in sprint performance is largely unaffected by age or maturation and no strong relationships exist between the magnitude of asymmetry and maximal sprint velocity.

Influence of Age, Maturity, and Body Size on the Spatiotemporal Determinants of Maximal Sprint Speed in Boys.

Meyers, RW, Oliver, JL, Hughes, MG, Lloyd, RS, and Cronin, JB. Influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. J Strength Cond Res 31(4): 1009-1016, 2017-The aim of this study was to investigate the influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. Three-hundred and seventy-five boys (age: 13.0 ± 1.3 years) completed a 30-m sprint test, during which maximal speed, step length, step frequency, contact time, and flight time were recorded using an optical measurement system. Body mass, height, leg length, and a maturity offset represented somatic variables. Step frequency accounted for the highest proportion of variance in speed (∼58%) in the pre-peak height velocity (pre-PHV) group, whereas step length explained the majority of the variance in speed (∼54%) in the post-PHV group. In the pre-PHV group, mass was negatively related to speed, step length, step frequency, and contact time; however, measures of stature had a positive influence on speed and step length yet a negative influence on step frequency. Speed and step length were also negatively influence by mass in the post-PHV group, whereas leg length continued to positively influence step length. The results highlighted that pre-PHV boys may be deemed step frequency reliant, whereas those post-PHV boys may be marginally step length reliant. Furthermore, the negative influence of body mass, both pre-PHV and post-PHV, suggests that training to optimize sprint performance in youth should include methods such as plyometric and strength training, where a high neuromuscular focus and the development force production relative to body weight are key foci.

Pig islet xenotransplantation.

PURPOSE OF REVIEW: The current article reviews the rationale, sources and preparation of pig islets for xenotransplantation, and presents current progress in solving the problems associated with establishing pig islet transplant as a clinical treatment for type 1 diabetes. SUMMARY: Islet transplantation is an effective treatment option for type 1 diabetes, but the available supply of human pancreases is insufficient to meet the need and demand for obtaining islets. Pig islets provide a readily available source for islet transplantation, with trials in non-human primates demonstrating their potential to reverse diabetes. The risk of zoonosis can be reduced by designated pathogen-free breeding of the donor pigs, but porcine endogenous retroviruses (PERVs) that are integrated into the genome of all pigs are especially difficult to eliminate. However, clinical trials have demonstrated an absence of PERV transmission with a significant reduction in the number of severe hypoglycemic episodes and up to 30% reduction in exogenous insulin doses. A number of methods such as production of various transgenic pigs to better xenotransplantation efficiency and the encapsulation of islets to isolate them from the host immune system are currently being tested to overcome the xenograft immune rejection. Furthermore, ongoing research is also shedding light on factors such as the age and breed of the donor pig to determine the optimal islet quantity and function.

Cardiac structure and function in adolescent Sherpa; effect of habitual altitude and developmental stage.

The purpose of this study was to examine ventricular structure and function in Sherpa adolescents to determine whether age-specific differences in oxygen saturation (SpO2 ) and pulmonary artery systolic pressure (PASP) influence cardiac adaptation to chronic hypoxia early in life. Two-dimensional, Doppler, and speckle-tracking echocardiography were performed on adolescent (9-16 yr) highland Sherpa (HLS; 3,840 m; n = 26) and compared with age-matched lowland Sherpa (LLS; 1,400 m; n = 10) and lowland Caucasian controls (LLC; sea level; n = 30). The HLS were subdivided into pre- and postadolescence; SpO2 was also recorded. Only HLS exhibited a smaller relative left ventricular (LV) end-diastolic volume; however, both HLS and LLS demonstrated a lower peak LV untwisting velocity compared with LLC (92 ± 26 and 100 ± 45 vs. 130 ± 43°/s, P < 0.05). Although SpO2 was similar between groups, PASP was higher in post- vs. preadolescent HLS (30 ± 5 vs. 25 ± 5 mmHg, P < 0.05), which negatively correlated with right ventricular strain rate (r = 0.50, P < 0.01). Much like their adult counterparts, HLS and LLS adolescents exhibit slower LV diastolic relaxation, despite residing at different altitudes. These findings suggest fundamental differences exist in the diastolic function of Sherpa that are present at an early age and may be retained after migration to lower altitudes. The higher PASP in postadolescent Sherpa is in contrast to previous reports of lowland children at high altitude and, unlike that in lowlanders, was not explained by differences in SpO2 ; thus different regulatory mechanisms seem to exist between these two distinct populations.

Maximal sprint speed in boys of increasing maturity.

The purpose of this study was to examine the natural development of the mechanical features of sprint performance in relation to maturation within a large cohort of boys. Three hundred and thirty-six boys (11-15 years) were analyzed for sprint performance and maturation. Maximal speed, stride length (SL), stride frequency (SF), flight time (FT) and contact time (CT) were assessed during a 30m sprint. Five maturation groups (G1-5) were established based on age from peak height velocity (PHV) where G1=>2.5years pre-PHV, G2 = 2.49-1.5years pre-PHV, G3 = 1.49-0.5years pre-PHV, G4 = 0.49years pre- to 0.5years post-PHV and G5 = 0.51-1.5years post-PHV. There was no difference in maximal speed between G1, G2 and G3 but those in G4 and G5 were significantly faster (p < .05) than G1-3. Significant increases (p < .05) in SL were observed between groups with advancing maturation, except G4 and G5 (p > .05). SF decreased while CT increased (both p < .05) between G1, G2 and G3, but no further significant changes (p > .05) were observed for either variable between G3, G4 and G5. While G1-3 increased their SL, concomitant decreases in SF and increases in CT prevented them from improving maximal speed. Maximal sprint speed appears to develop around and post-PHV as SF and CT begin to stabilize, with increases in maximal sprint speed in maturing boys being underpinned by increasing SL.

Reliability of the Spatiotemporal Determinants of Maximal Sprint Speed in Adolescent Boys Over Single and Multiple Steps.

The purpose of this study was to examine the reliability of the spatiotemporal determinants of maximal sprinting speed in boys over single and multiple steps. Fifty-four adolescent boys (age = 14.1 ± 0.7 years [range = 12.9-15.7 years]; height = 1.63 ± 0.09 m; body mass = 55.3 ± 13.3 kg; -0.31 ± 0.90 age from Peak Height Velocity (PHV) in years; mean ± s) volunteered to complete a 30 m sprint test on 3 occasions over a 2-week period. Speed, step length, step frequency, contact time, and flight time were assessed via an optical measurement system. Speed and step characteristics were obtained from the single-fastest step and average of the 2 and 4 fastest consecutive steps. Pairwise comparison of consecutive trials revealed the coefficient of variation (CV) for speed was greater in 4-step (CV = 7.3 & 7.5%) compared with 2-step (CV = 4.2 & 4.1%) and 1-step (CV = 4.8 & 4.6%) analysis. The CV of step length, step frequency and contact time ranged from 4.8 to 7.5% for 1-step, 3.8-5.0% for 2-step and 4.2-7.5% for 4-step analyses across all trials. An acceptable degree of reliability was achieved for the spatiotemporal and performance variables assessed in this study. Two-step analysis demonstrated the highest degree of reliability for the key spatiotemporal variables, and therefore may be the most suitable approach to monitor the spatiotemporal characteristics of maximal sprint speed in boys.

Association of MCAT scores obtained with standard vs extra administration time with medical school admission, medical student performance, and time to graduation.

IMPORTANCE: Individuals with documented disabilities may receive accommodations on the Medical College Admission Test (MCAT). Whether such accommodations are associated with MCAT scores, medical school admission, and medical school performance is unclear. OBJECTIVE: To determine the comparability of MCAT scores obtained with standard vs extra administration time with respect to likelihood of acceptance to medical school and future medical student performance. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of applicants to US medical schools for the 2011-2013 entering classes who reported MCAT scores obtained with standard time (n = 133,962) vs extra time (n = 435), and of students who matriculated in US medical schools from 2000-2004 who reported MCAT scores obtained with standard time (n = 76,262) vs extra time (n = 449). EXPOSURES: Standard or extra administration time during MCAT. MAIN OUTCOMES AND MEASURES: Primary outcome measures were acceptance rates at US medical schools and graduation rates within 4 or 5 years after matriculation. Secondary outcome measures were pass rates on the United States Medical Licensing Examination (USMLE) Step examinations and graduation rates within 6 to 8 years after matriculation. RESULTS: Acceptance rates were not significantly different for applicants who had MCAT scores obtained with standard vs extra time (44.5% [59,585/133,962] vs 43.9% [191/435]; difference, 0.6% [95% CI, -4.1 to 5.3]). Students who tested with extra time passed the Step examinations on first attempt at significantly lower rates (Step 1, 82.1% [344/419] vs 94.0% [70,188/74,668]; difference, 11.9% [95% CI, 9.6% to 14.2%]; Step 2 CK, 85.5% [349/408] vs 95.4% [70,476/73,866]; difference, 9.9% [95% CI, 7.8% to 11.9%]; Step 2 CS, 92.0% [288/313] vs 97.0% [60,039/61,882]; difference, 5.0% [95% CI, 3.1% to 6.9%]). They also graduated from medical school at significantly lower rates at different times (4 years, 67.2% [285/424] vs 86.1% [60,547/70,305]; difference, 18.9% [95% CI, 15.6% to 22.2%]; 5 years, 81.6% [346/424] vs 94.4% [66,369/70,305]; difference, 12.8% [95% CI, 10.6% to 15.0%]; 6 years, 85.4% [362/424] vs 95.8% [67,351/70,305]; difference, 10.4% [95% CI, 8.5% to 12.4%]; 7 years, 88.0% [373/424] vs 96.2% [67,639/70,305]; difference, 8.2% [95% CI, 6.4% to 10.1%]; 8 years, 88.4% [375/424] vs 96.5% [67,847/70,305]; difference, 8.1% [95% CI, 6.3% to 9.8%]). These differences remained after controlling for MCAT scores and undergraduate grade point averages. CONCLUSIONS AND RELEVANCE: Among applicants to US medical schools, those with MCAT scores obtained with extra test administration time, compared with standard administration time, had no significant difference in rate of medical school admission but had lower rates of passing the USMLE Step examinations and of medical school graduation within 4 to 8 years after matriculation. These findings raise questions about the types of learning environments and support systems needed by students who test with extra time on the MCAT to enable them to succeed in medical school.

The impact of recipient obesity on outcomes after renal transplantation.

BACKGROUND: The benefit of renal transplantation in obese patients is controversial, with many centers setting upper limits on body mass index (BMI) in consideration for listing patients for transplant. This study was undertaken to determine the effect of recipient obesity on delayed graft function (DGF) and graft survival after renal transplantation. METHODS: Retrospective review of all renal transplant recipients in the United Network for Organ Sharing database from January 1, 2004, through December 31, 2009, was performed. Primary endpoints were DGF and non-death-censored graft survival. Comparisons were made on the basis of the following weight classes: nonobese (BMI < 30), class I obese (30 ≤ BMI < 35), class II obese (35 ≤ BMI < 40), and class III obese (BMI ≥ 40). RESULTS: Multivariable logistic regression indicated a significantly increased risk for DGF in obese patients. The odds ratios for DGF compared with nonobese patients were 1.34 [95% confidence interval (CI) 1.27-1.42; P < 0.001], 1.68 (95% CI 1.56-1.82; P < 0.001), and 2.68 (95% CI 2.34-3.07; P < 0.001) for the class I obese, class II obese, and class III obese groups, respectively. Class I obesity was not a significant risk for non-death-censored graft failure [hazard ratio (HR) 1.00, 95% CI 0.95-1.05; P = 0.901] compared with nonobese patients. Patients in the class II obese (HR 1.15, 95% CI 1.07-1.24; P < 0.001) and class III obese (HR 1.26, 95% CI 1.11-1.43; P < 0.001) groups were at a significantly increased risk for graft failure than their nonobese counterparts. CONCLUSIONS: Obese patients in all weight classes are at an increased risk for DGF after renal transplantation, although differences in non-death-censored graft survival are such that transplantation should not be denied on the basis of BMI criteria alone.

Effects of playing surface on physiological responses and performance variables in a controlled football simulation.

In spite of the increased acceptance of artificial turf in football, few studies have investigated if matches are altered by the type of surface used and no research has compared physiological responses to football activity on artificial and natural surfaces. In the present study, participants performed a football match simulation on high-quality artificial and natural surfaces. Neither mean heart rate (171 ± 9 beats · min(-1) vs. 171 ± 9 beats · min(-1); P > 0.05) nor blood lactate (4.8 ± 1.6 mM vs. 5.3 ± 1.8 mM; P > 0.05) differed between the artificial and natural surface, respectively. Measures of sprint, jumping and agility performance declined through the match simulation but surface type did not affect the decrease in performance. For example, the fatigue index of repeated sprints did not differ (P > 0.05) between the artificial, (6.9 ± 2.1%) and natural surface (7.4 ± 2.4%). The ability to turn after sprinting was affected by surface type but this difference was dependent on the type of turn. Although there were small differences in the ability to perform certain movements between artificial and natural surfaces, the results suggest that fatigue and physiological responses to football activity do not differ markedly between surface-type using the high-quality pitches of the present study.

The race for space: Modelling the landward migration of coastal wetlands under sea level rise at regional scale.

Globally, sea-level rise (SLR) is a major environmental challenge for coastal ecosystems. Of particular concern are the impacts on intertidal wetlands, the loss of which would have detrimental consequences for both human and ecological communities. On the south-east Australian coast, case studies suggest that the future of intertidal wetlands will greatly depend on landward migration as surface accretion may not keep up with the predicted SLR in many estuaries. However, due to differences in geomorphological settings and land-use, estuaries vary in their capacity to accommodate lateral migration. Regional scale assessment of the lateral accommodation space is therefore critical for pre-emptive planning to conserve these valuable coastal ecosystems. In this study, we analysed wetland lateral accommodation space distribution within 110 estuaries under three SLR scenarios and three land management options on the New South Wales coast, south-east Australia. From the wetland distribution predictions, we calculated and mapped the lateral accommodation space in each estuary associated with each sea level and land use scenario. We further investigated the relationships between wetland migration capacity, intertidal hypsometry represented by elevation skewness, and estuary type within a Bayesian analysis framework. Our results showed that while a few large riverine estuaries dominated the state's total accommodation space, saline wetlands were at risk of disappearing from most intermittently closed-open estuaries if they cannot vertically accrete at the pace of SLR. These distinct responses to SLR are due to different elevation distributions. Furthermore, our assessment of land use adaptation options suggested that the promotion of landward migration without impairing other important ecosystems could be achieved by making low intensity land uses available within several riverine estuaries and barrier (open entrance) estuaries. Through identifying migration opportunities and barriers, the findings of the study could support regional scale adaptation strategies to ensure the sustainability of wetland-associated ecosystem goods and services.

Transduction of human T cells with a novel T-cell receptor confers anti-HCV reactivity.

Hepatitis C Virus (HCV) is a major public health concern, with no effective vaccines currently available and 3% of the world's population being infected. Despite the existence of both B- and T-cell immunity in HCV-infected patients, chronic viral infection and HCV-related malignancies progress. Here we report the identification of a novel HCV TCR from an HLA-A2-restricted, HCV NS3:1073-1081-reactive CTL clone isolated from a patient with chronic HCV infection. We characterized this HCV TCR by expressing it in human T cells and analyzed the function of the resulting HCV TCR-transduced cells. Our results indicate that both the HCV TCR-transduced CD4(+) and CD8(+) T cells recognized the HCV NS3:1073-1081 peptide-loaded targets and HCV(+) hepatocellular carcinoma cells (HCC) in a polyfunctional manner with cytokine (IFN-gamma, IL-2, and TNF-alpha) production as well as cytotoxicity. Tumor cell recognition by HCV TCR transduced CD8(-) Jurkat cells and CD4(+) PBL-derived T cells indicated this TCR was CD8-independent, a property consistent with other high affinity TCRs. HCV TCR-transduced T cells may be promising for the treatment of patients with chronic HCV infections.

A review of the United States experience with combined heart-liver transplantation.

Since first described by Starzl, combined heart and liver transplantation (CHLT) has been a relatively rare event, although utilization has increased in the past decade. This study was undertaken to review the United States experience with this procedure; UNOS data on CHLT was reviewed. CHLT was compared with liver transplantation alone and heart transplantation alone in terms of acute rejection within 12 months, graft survival, and patient survival. Survival was calculated according to Kaplan-Meier and Cox proportional hazards. Continuous variables were compared using Student's t-test and categorical variables with chi-squared. Between 1987 and 2010, there were 97 reported cases of CHLT in the United States. Amyloidosis was the most common indication for both heart (n = 26, 26.8%) and liver (n = 27, 27.8%) transplantation in this cohort. Liver graft survival in the CHLT cohort at 1, 5, and 10 years was 83.4%, 72.8%, and 71.0%, whereas survival of the cardiac allograft was 83.5%, 73.2%, and 71.5%. This was similar to graft survival in liver alone transplantation (79.4%, 71.0%, 65.1%; P = 0.894) and heart transplantation alone (82.6%, 71.9%, 63.2%; P = 0.341). CHLT is a safe and effective procedure, with graft survival rates similar to isolated heart and isolated liver transplantation.

The reliability of jump kinematics and kinetics in children of different maturity status.

The purpose of this study was to determine the reliability of eccentric (ECC) and concentric (CON) kinematic and kinetic variables thought to be critical to jump performance during bilateral vertical countermovement jump (VCMJ) and horizontal countermovement jump (HCMJ) across children of different maturity status. Forty-two athletic male and female participants between 9 and 16 years of age were divided into 3 maturity groups according to peak height velocity (PHV) offset (Post-PHV, At-PHV, and Pre-PHV) and percent of predicted adult stature. All the participants performed 3 VCMJ and HCMJ trials and the kinematics, and kinetics of these jumps were measured via a force plate over 3 testing sessions. In both jumps, vertical CON mean and peak power and jump height or distance were the most reliable measures across all groups (change in the mean [CM] = -5.4 to 6.2%; coefficient of variation [CV] = 2.1-9.4%; Intraclass correlation coefficient [ICC] = 0.82-0.98), whereas vertical ECC mean power was the only ECC variable with acceptable reliability for both jumps (CM = -0.7 to 10.1%; CV = 5.2-15.6%; ICC = 0.74-0.97). A less mature state was "likely" to "very likely" to reduce the reliability of the HCMJ ECC kinetics and kinematics. These findings suggested that movement variability is associated with the ECC phase of CMJs, especially in Pre-PHV during the HCMJ. Vertical CON mean and peak power and ECC mean power were deemed reliable and appropriate to be used in children as indicators of jump and stretch-shortening cycle performance.

The effects of 4-weeks of plyometric training on reactive strength index and leg stiffness in male youths.

Although previous pediatric research has reported performance improvements in muscular power, agility, speed, and rate-of-force development after exposure to plyometric training, the effects on reactive strength index (RSI) and leg stiffness remain unclear. One hundred and twenty-nine boys from 3 different age groups (9, 12, and 15 years) participated and were divided into either an experimental (EXP) or control (CON) group within their respective age groups. The EXP groups followed a twice-weekly, 4-week plyometric training program, whereas the CON groups participated in their normal physical education lessons. Preintervention and postintervention measures were collected for RSI (during maximal hopping) and leg stiffness (during submaximal hopping). Both 12- and 15-year-old EXP groups made significant improvements in both absolute and relative leg stiffness (p < 0.05). The 9-year-old EXP group and CON groups for all ages did not make significant changes in leg stiffness. The 12-year-old EXP cohort also made significant improvements in RSI (p < 0.05). Both 15- and 9-year-old EXP cohorts, and CON groups for all ages, failed to show any significant improvements in RSI. The study concludes that improvements in RSI and leg stiffness after a 4-week plyometric training program are age dependent during childhood.

Baseline predictive factors for foregut and hindgut response to long-term gastric electrical stimulation using augmented energy.

INTRODUCTION: Gastric electrical stimulation (GES) has been recommended for drug refractory patients with gastroparesis, but no clear baseline predictors of symptom response exist. We hypothesized that long-term predictors to GES for foregut and hindgut symptoms exist, particularly when using augmented energies. PATIENTS: We evaluated 307 patients at baseline, 1 week post temporary GES, and one year after permanent GES. Baseline measures included upper and lower symptoms by patient-reported outcomes (PRO), solid and liquid gastric emptying (GET), cutaneous, mucosal, and serosal electrophysiology (EGG, m/s EG), BMI, and response to temporary stimulation. METHODS: Foregut and hindgut PRO symptoms were analyzed for 12-month patient outcomes. All patients utilized a standardized energy algorithm with the majority of patients receiving medium energy at 12 months. Patients were categorized based on change in average GI symptom scores at the time of permanent GES compared to baseline using a 10% decrease over time as the cutoff between improvers versus non-improvers. RESULTS: By permanent GES implant, average foregut and hindgut GI symptom scores reduced 42% in improved patients (n = 199) and increased 27% in non-improved patients (n = 108). Low BMI, baseline infrequent urination score, mucosal EG ratio, and proximal mucosal EG low-resolution amplitude remained significant factors for improvement status. CONCLUSIONS: GES, for patients responding positively, improved both upper/foregut and lower/hindgut symptoms with most patients utilizing higher than nominal energies. Low baseline BMI and the presence of infrequent urination along with baseline gastric electrophysiology may help identify those patients with the best response to GES/bio-electric neuromodulation.