Anabolic steroids after total knee arthroplasty. A double blinded prospective pilot study

Background: Total knee arthroplasty is reported to improve the patient’s quality of life and mobility. However loss of mobility and pain prior to surgery often results in disuse atrophy of muscle. As a consequence the baseline functional state prior to surgery may result in poorer outcome “post surgery” and extended rehabilitation may be required. The use of anabolic steroids for performance enhancement and to influence muscle mass is well established. The positive effects of such treatment on bone and muscle could therefore be beneficial in the rehabilitation of elderly patients. The purpose of this study was to investigate the effects of small doses of Nandrolone decanoate on recovery and muscle strength after total knee replacement and to establish the safety of this drug in multimorbid patients. Methods: This study was designed as a prospective double blind randomized investigation. Five patients (treatment group) with a mean age of 66.2 (58-72), average BMI of 30.76 (24.3-35.3) received 50 mg nandrolone decanoate intramuscular bi-weekly for 6 months. The control group (five patients; mean age 65.2, range 59-72; average BMI 31.7, range 21.2-35.2) was injected with saline solution. “Pre-operatively” and “post-operatively” (6 weeks, 3,6,9 and 12 months) all patients were assessed using the knee society score (KSS), isokinetic strength testing and functional tests (a sit-to-stand and timed walking tests). In addition, a bone density scan was used preoperatively and 6 month postoperatively to assess bone mineral density. Results: Whilst the steroid group generally performed better than the placebo group for all of the functional tests, ANOVA failed to reveal any significant differences. The steroid group demonstrated higher levels of quadriceps muscle strength across the postoperative period which reached significance at 3 (p = 0.02), 6 (p = 0.01), and 12 months (p = 0.02). There was a significant difference for the KSS at 6 weeks (p = 0.02), 6 (p = 0.02) and 12 month (p = 0.01). The steroid group demonstrated a reduction in the amount of bone mineral density at both the femur and lumbar spine from “pre-” to “post-surgery”, however, these results did not reach significance (p < 0.05) using one-way ANOVA. Conclusions: This project strongly suggests that the use of anabolic steroids result in an improved outcome as assessed by the KSS and significantly increases extensor strength. No side effects were seen in either the study or control group. Trial Registration Number: Regional Health District: Register No. 03.05 Human Research Ethics Committee University: Clearance Number: 04/03-1

Phase locking below rate threshold in noisy model neurons

The property of a neuron to phase-lock to an oscillatory stimulus before adapting its spike rate to the stimulus frequency plays an important role for the auditory system. We investigate under which conditions neurons exhibit this phase locking below rate threshold. To this end, we simulate neurons employing the widely used leaky integrate-and-fire (LIF) model. Tuning parameters, we can arrange either an irregular spontaneous or a tonic spiking mode. When the neuron is stimulated in both modes, a significant rise of vector strength prior to a noticeable change of the spike rate can be observed. Combining analytic reasoning with numerical simulations, we trace this observation back to a modulation of interspike intervals, which itself requires spikes to be only loosely coupled. We test the limits of this conception by simulating an LIF model with threshold fatigue, which generates pronounced anticorrelations between subsequent interspike intervals. In addition we evaluate the LIF response for harmonic stimuli of various frequencies and discuss the extension to more complex stimuli. It seems that phase locking below rate threshold occurs generically for all zero mean stimuli. Finally, we discuss our findings in the context of stimulus detection

Auditory reafferences: The influence of real-time feedback on movement control

© 2015 Kennel, Streese, Pizzera, Justen, Hohmann and Raab. Auditory reafferences are real-time auditory products created by a person's own movements. Whereas the interdependency of action and perception is generally well studied, the auditory feedback channel and the influence of perceptual processes during movement execution remain largely unconsidered. We argue that movements have a rhythmic character that is closely connected to sound, making it possible to manipulate auditory reafferences online to understand their role in motor control. We examined if step sounds, occurring as a by-product of running, have an influence on the performance of a complex movement task. Twenty participants completed a hurdling task in three auditory feedback conditions: a control condition with normal auditory feedback, a white noise condition in which sound was masked, and a delayed auditory feedback condition. Overall time and kinematic data were collected. Results show that delayed auditory feedback led to a significantly slower overall time and changed kinematic parameters. Our findings complement previous investigations in a natural movement situation with non-artificial auditory cues. Our results support the existing theoretical understanding of action-perception coupling and hold potential for applied work, where naturally occurring movement sounds can be implemented in the motor learning processes

Dominance or tolerance? Causes and consequences of a period of increased intercommunity encounters among bonobos (Pan paniscus) at LuiKotale

Group-living primates exhibit variable reactions to intergroup encounters (or IGEs), reflecting species-specific strategies and individual motivations. In chimpanzees (Pan troglodytes), dominating in IGEs provides fitness benefits. Less is known about responses to IGEs in bonobos (Pan paniscus) despite their equal relevance for understanding the origins of human intergroup relations. We observed the Bompusa West (WBp) bonobo community at LuiKotale during a 2-month shift in ranging resulting in frequent IGEs with the smaller Bompusa East (EBp) community. We tested whether incursions provided ecological benefits, and whether responses to IGEs were consistent with inter-community dominance or tolerance. We measured fruit availability and collected activity scans from 26 mature WBp community members when in their core ranging area, during incursions into the EBp ranging area, and during IGEs. We collected data on sexual interactions and aggression with in-group and out-group members during 19 independent IGEs. During their shift in ranging, fruit availability was greater in the EBp ranging area, and WBp bonobos consumed more fruit during incursions than when in their core ranging area. Coalitionary intergroup aggression occurred during nine IGEs, and outcomes were consistent with imbalances in fighting power, in that larger WBp parties supplanted smaller EBp parties from the immediate area. However, communities reformed associations following 70% of coalitionary conflicts, and prolonged IGEs facilitated out-group sexual interactions and female transfers. The WBp community shift in ranging was likely motivated by ecological factors and responses to increased IGEs reflected a mixture of competitive and tolerant strategies

Solution Sets for Inverse Non-Cooperative Linear-Quadratic Differential Games

This letter addresses the inverse problem of differential games, where the aim is to compute cost functions which lead to observed Nash equilibrium trajectories. The solution of this problem allows the generation of a model for inferring the intent of several agents interacting with each other. We present a method to find all cost functions which lead to the same Nash equilibrium in an infinite-horizon LQ differential game. The approach relies on a reformulation of the coupled matrix Riccati equations which arise out of necessary and sufficient conditions for Nash equilibria. Furthermore, based on our findings, we present an approach to compute a solution given a set of observed state and control trajectories. Our results highlight properties of feedback Nash equilibria in LQ differential games and provide an efficient approach for the estimation of cost function matrices in such a scenario

Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle

The time-frequency uncertainty principle states that the product of the temporal and frequency extents of a signal cannot be smaller than $1/(4\pi)$. We study human ability to simultaneously judge the frequency and the timing of a sound. Our subjects often exceeded the uncertainty limit, sometimes by more than tenfold, mostly through remarkable timing acuity. Our results establish a lower bound for the nonlinearity and complexity of the algorithms employed by our brains in parsing transient sounds, rule out simple "linear filter" models of early auditory processing, and highlight timing acuity as a central feature in auditory object processing.Comment: 4 pages, 2 figures; Accepted at PR

Editorial: Molecular intricacies of Trichoderma-plant-pathogen interactions

Trichoderma spp. are widely used as plant disease biocontrol agents around the world (Guzmán-Guzmán, 2019). Initial research on Trichoderma focused on their biocontrol ability mediated by mycoparasitism and antibiosis. Trichoderma spp. are known for direct antagonistic action on plant pathogenic fungi, and more recently for indirect suppression via induced defense. Thus, with the discovery that Trichoderma spp. can internally colonize roots and invoke defense responses in plants, attention of the research community largely shifted toward understanding how the plants and Trichoderma communicate with each other leading to a symbiosis-like relationship (Harman et al., 2004; Hohmann, 2012). At the initial attachment stage, Trichoderma spp. are known to secrete hydrophobins that could aid in adhesion to the root surface (Viterbo and Chet, 2006). Following attachment, secretion of plant cell wall degrading enzymes like pectate lyase (Morán Diez et al., 2009) and swollenin (Brotman et al., 2008; Andberg et al., 2015; Cosgrove, 2017) could facilitate penetration. It is important to note that penetration into the root is limited, and indeed genes encoding plant cell wall degrading enyzymes are downregulated early in root colonization (Estrada-Rivera et al., 2020). This occurs along with high representation of glycosyl hydrolases in the secretome (Nogueira-Lopez et al., 2018). Soluble enzymes may still be present in the secretome after the corresponding transcripts decrease, highlighting the need for obtaining well-resolved time course experiments for both gene expression and protein abundance during early colonization events. Trichoderma fungi are known to secrete a large number of small secreted cysteine-rich proteins (SSCPs) that might be involved in modulation of plant defense, fine tuning of which may be responsible for the outcome of this association. Though not clearly established, it seems possible that Trichoderma SSCPs initially suppress plant defense, and once the colonization is complete, induces plant defense to enter into a symbiosis-like relationship. Unlike mycorrhiza, there seems to exist no specificity in Trichoderma-plant association, which appears to be quite universal. For example, AM mycorrhizal fungi cannot colonize cruciferous roots exhibiting a level of specificity, but Trichoderma can effectively colonize such roots, indicating a generalist type of lifestyle

Inverse Open-Loop Noncooperative Differential Games and Inverse Optimal Control

We consider the problem of computing parameters of player cost functionals such that given state and control trajectories constitute an open-loop Nash equilibrium for a noncooperative differential game. We propose two methods for solving this inverse differential game problem and novel conditions under which our methods compute unique cost-functional parameters. Our conditions are analogous to persistence of excitation conditions in adaptive control and parameter estimation. The efficacy of our methods is illustrated in simulations