Nationwide Subjective and Objective Assessments of Potential Talent Predictors in Elite Youth Soccer: An Investigation of Prognostic Validity in a Prospective Study.

Recent studies have provided empirical evidence on the prognostic relevance of objective performance diagnostics in the soccer talent identification and development process. However, little is known about the prognostic validity of coaches' subjective evaluations of performance. This study evaluated objective and subjective assessments within a nationwide talent development program and addressed motor, perceptual skill, and personality-related performance factors. Male players (N = 13,869; M age = 12.59 ± 1.07 years) from the age groups U12 to U15 of the German soccer talent development program participated in this study. Participants completed an objective motor diagnostic (sprint, agility, dribbling, ball control, juggling) and were subjectively rated by their coaches (kicking skills, endurance, individual tactical skills, psychosocial skills). All nine predictors were assessed with sufficient psychometric properties (α ≥ 0.72; except dribbling and ball control: α ≥ 0.53). Players' success three seasons later was operationalized by achieving professional youth academy level or not (success rate, 9%). Independent-samples t-tests analyzed univariate mean group comparisons between future selected and non-selected players. Logistic regression models examined the multivariate prognostic validity of all assessments by predicting success with subjective (model 1), objective (model 2), and both groups of predictors (model 3). Confirming the univariate prognostic validity, future selected outperformed non-selected players regarding all predictors (each p < 0.001, except for agility in U15: p < 0.01). Tactical skills, kicking skills, and sprint were of highest predictive value (d ≥ 0.61 in each age group). Multivariate results provided empirical evidence for the subjective (7% ≤ Nagelkerke's R 2 ≤ 11%; each p < 0.001) and objective (8% ≤ Nagelkerke's R 2 ≤ 13%; each p < 0.001) assessments' prognostic validity. However, model 3 revealed the best statistical explanatory power in each age group (0.15 ≤ Nagelkerke's R 2 ≤ 0.20; p < 0.001). In this combined assessment model, sprint, tactical skills, and dribbling were found to be the most predictive variables. In conclusion, this study reinforces the call for multidimensional diagnostics integrating objective and subjective assessments. Future research is needed to address the demands for longitudinal analyses of subjective ratings, the integration of biological maturation, and empirical evidence for female soccer.

Relative Age-Related Biases in Objective and Subjective Assessments of Performance in Talented Youth Soccer Players.

Talent research has recommended that multidimensional assessments of performance are needed to improve the identification and development of talented young athletes. However, factors such as the relative age effect may cloud our ability to assess factors related to performance. The aim of this study was to determine the extent of any relationship between soccer players' chronological and relative age, and objective and subjective performance assessments. Data for highly talented male soccer players selected into the German Soccer Associations' talent promotion program (N = 16,138) for U12 to U15 age groups (M age = 12.62 ± 1.04 years) were examined. Besides anthropometric assessments, players completed a battery of five motor tests that objectively assessed speed abilities and technical skills (specifically sprint, agility, dribbling, ball control, and juggling). In addition, coaches subjectively rated players on their kicking, tactical, and psychosocial skills, as well as providing holistic evaluations of each player's current and future performance levels. Correlation analyses were used to investigate the extent of any relationships between the chronological and relative age of players and their results for each of the assessments. A strong linear decrease in the frequency of later-born players confirmed the overrepresentation of early-born players in all age groups (0.92 ≤ |r| ≤ 0.95, each p < 0.001). From U12 to U15, significant (each p < 0.001) correlations were found between the chronological age of players and their height (|r| = 0.70), weight (|r| = 0.69), speed abilities (|r| = 0.38), and technical skills (|r| = 0.43). When evaluating each age group separately, small effects were found when correlating relative age with the anthropometric assessments (0.18 ≤ |r| ≤ 0.26), and only trivial effects with speed abilities and technical skills (0.01 ≤ |r| ≤ 0.06). Similarly, low correlations were found for the subjective evaluations of kicking, tactical, and psychosocial skills with chronological age across age groups (0.03 ≤ |r| ≤ 0.07), and with relative age in each age group (0.01 ≤ |r| ≤ 0.11). The results show a skewed distribution toward early-born players and-in reference to their relative age-advanced performance in late-born athletes. However, trends toward a better holistic rating of early-born players for current and future performance levels were found. Coaches should be aware of these effects during talent selection, but also when interpreting results from subjective and objective assessments of performance.

17-beta estradiol promotion of herpes simplex virus type 1 reactivation is estrogen receptor dependent.

Correlations between estrogen and herpes simplex virus (HSV) reactivation from latency have been suggested by numerous clinical reports, but causal associations are not well delineated. In a murine HSV-1 corneal infection model, we establish 17-beta estradiol (17-betaE) treatment of latently infected ovariectomized mice induces viral reactivation, as demonstrated by increased viral load and increased immediate-early viral gene expression in the latently infected trigeminal ganglia (TG). Interestingly, the increased HSV reactivation occurred in the absence of inhibition of viral specific CD8(+) T-cell effector function. 17-betaE administration increased HSV reactivation in CD45(+) cell-depleted TG explant cultures, providing further support that leukocyte-independent effects on latently infected neurons were responsible for the increased reactivation. The drug-induced increases in HSV copy number were not recapitulated upon in vivo treatment of latently infected estrogen receptor alpha-deficient mice, evidence that HSV reactivation promoted by 17-betaE was estrogen receptor dependent. These findings provide additional framework for the emerging conceptualization of HSV latency as a dynamic process maintained by complex interactions among multiple cooperative and competing host, viral, and environmental forces. Additional research is needed to confirm whether pregnancy or hormonal contraceptives containing 17-betaE also promote HSV reactivation from latency in an estrogen receptor-dependent manner.

Microemboli detection and classification by innovative ultrasound technology during simulated neonatal cardiopulmonary bypass at different flow rates, perfusion modes, and perfusate temperatures.

The objective of this study was to detect and classify the number and size of gaseous microemboli in a simulated pediatric model of cardiopulmonary bypass. Tests were conducted at five different flow rates (400-1,200 ml/min in 200 ml/min increments), pulsatile versus nonpulsatile perfusion modes, and under normothermic, hypothermic, and deep hypothermic (35 degrees C, 25 degrees C, and 15 degrees C) conditions, yielding 180 total experiments. The circuit was primed with lactated Ringer's solution and filled with heparinized bovine blood. At the beginning of each experiment, 5 ml of air were injected into the venous line via the luer port of the oxygenator. Microemboli were quantified and classified by size for 5 minute segments at three transducer sites: postpump, postoxygenator, and postarterial filter. The purge line of the arterial filter was closed during all experiments. In all but one experiment, 90% of emboli at the postpump site were found to be smaller than 40 microm. At the postarterial filter site, nearly 99% of the emboli were smaller than 40 microm. Additionally, increasing microemboli counts were observed when the flow rate was increased and when the temperature was decreased. Lower temperatures, higher flow rates, and pulsatile perfusion were all associated with higher emboli counts. The majority of gaseous microemboli found in the simulated circuit was significantly below 40 microm; the smallest level detectable by traditional Doppler devices.

Pulsatile perfusion during cardiopulmonary bypass procedures in neonates, infants, and small children.

Multiple factors influence the outcome of cardiopulmonary bypass (CPB) procedures in pediatric patients with congenital heart defects. The benefit of pulsatile over nonpulsatile perfusion is one such factor that continues to be widely debated among researchers, perfusionists, and surgeons. However, by accurately measuring pulsatile flow in terms of energy equivalent pressure and surplus hemodynamic energy, pulsatile perfusion is clearly seen to replicate the physiologic heart in a manner unparalleled by nonpulsatile perfusion. Studied benefits of pulsatile perfusion in pediatric patients include increased vital organ blood flow and improvement in postoperative recovery. Also, the components of the extracorporeal circuit used in CPB are directly related to pulsatility and have a profound effect on hemodynamics in the circuit and the patient. Therefore, pulsatility and surplus hemodynamic energy delivery to the patient can be maximized by choosing the best performing heart-pumps, oxygenators, arterial filters, and cannulae. Furthermore, in using the most optimal circuit components available, the CPB procedure under pulsatile perfusion can proceed efficiently. Currently, the outcomes resulting from pulsatile perfusion in pediatric and adult patients, as well as animal models, are well documented. However, more multilaboratory efforts are necessary to understand and further validate the benefits of pulsatile perfusion in pediatric patients.

Survival of COPD patients using inhaled corticosteroids and long-acting beta agonists.

We conducted a historical cohort study to examine the relationship between survival and use of inhaled corticosteroids (ICS) and/or long-acting beta agonists (LABA) in patients with chronic obstructive pulmonary disease (COPD). All COPD patients aged 40 years who were enrolled in one of two regional managed care organizations during 1995-2000, and who had 90 days use of an ICS and/or LABA (N=1288) or of a short-acting bronchodilator (N=397), were identified. Of patients treated with ICS and/or LABA, 14.4% died during the follow-up period, as compared to 28.2% of comparison patients (P<0.01). In a Cox proportional hazards model that controlled for age, sex, comorbidities, COPD severity, and asthma status, a reduced risk of death was found for ICS treatment (HR 0.59 [95% CI 0.46-0.78]), LABA (HR 0.55 [0.34-0.89]), and ICS plus LABA treatment (HR 0.34 [0.21-0.56]). A second model that excluded any patient who also had an ICD-9 code for asthma (N=840) still found improved survival among those using the combination of ICS plus LABA (HR 0.35 [CI 0.17-0.71]). Additional analyses that varied the exposure criteria also found a consistent treatment benefit. Inclusion of ICS or bronchodilator treatment during the follow-up period as a time-dependent function appears to negate the survival benefit; however, the underlying assumptions for valid time-dependent modeling are clearly violated in this situation. In conclusion, we found that COPD patients who used ICS alone or in combination with LABA had substantially improved survival even after adjustment for asthma and other confounding factors.

A polymethylpentene fiber gas exchanger for long-term extracorporeal life support.

A polymethylpentene (PMP) fiber gas exchange device was evaluated in healthy sheep (35-42 kg) to characterize its performance and potential use in clinical extracorporeal life support (ECLS). Five PMP devices (1.3 m2) were compared with five silicone rubber membrane lung (SRML) devices (1.5 m2) that were supported on venovenous ECLS for 72 hours. The two device groups were compared for differences in gas exchange, device pressure gradient, hematology, blood biochemistry, and pathology. The results showed superiority in the PMP devices in both oxygen and CO2 exchange when compared at similar blood flow rates. Platelet consumption and the device pressure gradient were significantly less when using the PMP device. The device pressure gradient across the PMP devices was < 20 mm Hg as compared with > 150 mm Hg for the SRML devices at all blood flow rates. Changes in plasma hemoglobin levels, leukocyte counts, blood chemistry results, and pathologic findings were not significantly different between the two device groups. Plasma leakage or device failure did not occur in any of the test devices. These data support the use of the PMP device for extended circulatory support. Patients may fare better because of improved preservation of platelets, and the low resistance may allow for wider use of centrifugal-style pumps or the use of the device in a pumpless arteriovenous mode.

Improved planar amperometric nitric oxide sensor based on platinized platinum anode. 2. Direct real-time measurement of NO generated from porcine kidney slices in the presence of l-arginine, l-arginine polymers, and protamine.

Nitric oxide generation from porcine kidney slices is assessed using a new planar NO-selective amperometric sensor. The planar shape of the sensor allows for direct NO measurements near the surface (10 microm) of renal tissue slices in real time. Renal NO production may be modulated by the addition of L-arginine, arginine homopolymers (R2, R6, R10), and protamine, all of which can potentially transport across cellular membranes and provide a substrate for nitric oxide synthase within kidney parenchyma. Real-time amperometric measurements demonstrate that most L-arginine species can translocate across the cell membrane and rapidly increase NO production. However, no increase in NO generation is observed when the dimer of L-arginine (R2) is added to the solution bathing the tissue, suggesting that this species cannot permeate cell membranes. The degree of enhancement in NO generation observed for L-arginine and the larger peptides depends on the structure and follows the following sequence: R10 (decamer) > protamine > R6 (hexamer) > L-arginine. Protamine and the R10 decamer, especially, induce the largest increases in NO generation owing to their apparent rapid translocation into cells and subsequent cleavage by proteases to create high intracellular levels of L-arginine. The effect of sensor size (for sensor dimensions of 0.15- and 1-mm outer diameters) on the measured surface NO levels is also examined. The larger sensor traps more NO but hinders access of the L-arginine species to the tissue area between the flat distal plane of the sensor and the surface of the kidney slice. The use of such NO-generating peptides may be important in numerous biological systems that depend on NO production, such as ischemia-reperfusion injury and thrombogenesis.