Vergleichende Untersuchung zur muskulären Aktivität im Oberflächenelektromyogramm von Patienten nach konservativer, offen chirurgischer und minimalinvasiv-chirurgischer Behandlung von Wirbelsäulenverletzungen

Die Behandlung traumatischer Wirbelfrakturen kann chirurgisch oder konservativ erfolgen. Die chirurgische Behandlung wiederum kann mittels offener oder minimalinvasiver Instrumentierung durchgeführt werden. Die muskuläre Gewebealteration fällt bei der offenen Instrumentierung stärker aus als bei der minimalinvasiven Instrumentierung. Bei konservativ behandelten Patienten wird die Muskulatur durch die Behandlung nicht geschädigt. Patienten nach Wirbelfrakturen schilderten starke Einschränkung hinsichtlich ausdauernden Gehens mit muskulären Ermüdungserscheinungen und Schmerzen im Rücken. Ursache hierfür könnte eine schlechte intramuskuläre Koordination sein, deren zu hoher Grad an Aktivität mit zu Phasen geringer Aktivität zu schnellerer Ermüdung führt. Die muskuläre Aktivität der paravertebralen Muskulatur wurde mittels Oberflächenelektromyographie (EMG) erfasst. Die intramuskuläre Koordination wurde anhand des Variationskoeffizienten (CV) parametrisiert. Ziel war es, einen einfachen und praktikablen Parameter zu verwenden, der sowohl das mittlere Amplitudenniveau als auch die Kurvigkeit oder eine Schwankungsbreite der EMG-Verläufe während des zeitnormierten Schrittes berücksichtigt. Signifikante Einflüsse durch die Intervention ließen sich nicht finden. Die ermittelten Effektstärken unterstreichen dies. Insofern kann zu diesem mittelfristigen Zeitpunkt keine Überlegenheit einer der Interventionen hinsichtlich einer besseren intramuskulären Koordination attestiert werden. Um die Ursache der geschilderten Einschränkungen der Patienten besser zu verstehen, wären langfristige Untersuchungen der paravertebralen muskulären Ermüdung wünschenswert, um die Wahl der Intervention am muskelfunktionellen Outcome zu orientieren

Acute exercise impacts AhR and PD-1 levels of CD8+ T-cells

Purpose: The programmed cell death protein 1 (PD-1) has become a promising target in cancer immunotherapy. PD-1 expression of CD8+ T-cells may be increased via the exploitation of aryl hydrocarbon receptor (AhR) signaling with kynurenine (KYN) as a ligand. Since exercise affects KYN metabolism, we exploratory investigated the influence of acute exercise bouts on AhR and PD-1 levels of CD8+ T-cells. Method: In this study, 24 healthy males (age: 24.6 ± 3.9 years; weight 83.9 ± 10.5 kg; height: 182.4 ± 6.2 cm) completed a single bout of endurance (EE) and resistance exercise (RE) in a randomly assigned order on separate days. Blood samples were drawn before (t0), after (t1), and 1 h after (t2) both conditions. T-cell populations, the level of cytoplasmic AhR, and surface PD-1 were assessed by flow cytometry. Results: T-cell populations changed over time, indicated by an increase in the absolute numbers of CD3+ lymphocytes after EE (p < .001) and RE (p = .036) and in PD-1+ CD8+ T-cells after EE (p = .021). Proportions of T-cell populations changed only after EE (t0–t2: p = .029; t1-t2: p = .006). The level of cytoplasmic AhR decreased immediately after exercise in both exercise conditions (EE: p = .009; RE: p = .036). The level of surface PD-1 decreased 1 h after EE (p = .005). Conclusion: We analyzed the level of surface PD-1 and cytoplasmic AhR following acute physical exercise for the first time. Especially EE was observed to impact both AhR and PD-1 levels, undermining its role as the AhR-PD-1 axis modulator. These results provide new insights into the impact of exercise on AhR-signaling, which could potentially be relevant for various chronic diseases

Registration based assessment of femoral torsion for rotational osteotomies based on the contralateral anatomy

BACKGROUND Computer-assisted techniques for surgical treatment of femoral deformities have become increasingly important. In state-of-the-art 3D deformity assessments, the contralateral side is used as template for correction as it commonly represents normal anatomy. Contributing to this, an iterative closest point (ICP) algorithm is used for registration. However, the anatomical sections of the femur with idiosyncratic features, which allow for a consistent deformity assessment with ICP algorithms being unknown. Furthermore, if there is a side-to-side difference, this is not considered in error quantification. The aim of this study was to analyze the influence and value of the different sections of the femur in 3D assessment of femoral deformities based on the contralateral anatomy. MATERIAL AND METHODS 3D triangular surface models were created from CT of 100 paired femurs (50 cadavers) without pathological anatomy. The femurs were divided into sections of eponymous anatomy of a predefined percentage of the whole femoral length. A surface registration algorithm was applied to superimpose the ipsilateral on the contralateral side. We evaluated 3D femoral contralateral registration (FCR) errors, defined as difference in 3D rotation of the respective femoral section before and after registration to the contralateral side. To compare this method, we quantified the landmark-based femoral torsion (LB FT). This was defined as the intra-individual difference in overall femoral torsion using with a landmark-based method. RESULTS Contralateral rotational deviation ranged from 0° to 9.3° of the assessed femoral sections, depending on the section. Among the sections, the FCR error using the proximal diaphyseal area for registration was larger than any other sectional error. A combination of the lesser trochanter and the proximal diaphyseal area showed the smallest error. The LB FT error was significantly larger than any sectional error (p < 0.001). CONCLUSION We demonstrated that if the contralateral femur is used as reconstruction template, the built-in errors with the registration-based approach are smaller than the intraindividual difference of the femoral torsion between both sides. The errors are depending on the section and their idiosyncratic features used for registration. For rotational osteotomies a combination of the lesser trochanter and the proximal diaphyseal area sections seems to allow for a reconstruction with a minimal error

Acute hypertrophic but not maximal strength loading transiently enhances the kynurenine pathway towards kynurenic acid

Purpose Due to distinct immuno- and neuro-modulatory properties, growing research interest focuses on exercise-induced alterations of the kynurenine (KYN) pathway in healthy and clinical populations. To date, knowledge about the impact of different acute strength exercise modalities on the KYN pathway is scarce. Therefore, we investigated the acute effects of hypertrophic (HYP) compared to maximal (MAX) strength loadings on the KYN pathway regulation. Methods Blood samples of twelve healthy males (mean age and weight: 23.5 ± 3.2 years; 77.5 ± 7.5 kg) were collected before (T0), immediately after (T1), and 1 h after completion (T2) of HYP (5 sets with 10 repetitions at 80% of 1RM) and MAX (15 sets with 1RM) loadings performed in a randomized cross-over design. Serum concentrations of tryptophan (TRP), KYN, kynurenic acid (KA), and quinolinic acid (QA) were assessed using high-performance liquid chromatography. Results The KA/KYN ratio increased from T0 to T1 (p = 0.01) and decreased from T1 to T2 (p = 0.011) in HYP, while it was maintained within MAX. Compared to MAX, serum concentrations of KA were greater in HYP at T1 (p = 0.014). Moreover, the QA/KA ratio was significantly lower in HYP than in MAX at T1 (p = 0.002). Conclusion Acute HYP loading led to increases in the metabolic flux yielding KA, thereby possibly promoting immunosuppression and neuroprotection. Our findings emphasize the potential of acute HYP exercise as short-term modulator of KYN pathway downstream to KA in healthy males and need to be proven in other samples

Sleep problems and their interaction with physical activity and fatigue in hematological cancer patients during onset of high dose chemotherapy

Purpose Sleep problems reported by hematological cancer patients are usually linked to higher levels of cancer-related fatigue. Although the awareness of sleep problems in solid cancer patients is rising, there has been less attention to the issue in hematological cancer patients. The present study assesses the differences in sleep by comparing physical activity and fatigue levels among hematological cancer patients during the onset of chemotherapy. Furthermore, it investigates the relationship between sleep, physical activity, and fatigue through mediation analysis. Methods The recruited sample consists of 58 newly diagnosed hematological cancer patients (47.1 ± 15.4 yrs; 51.7% males). Subjects completed questionnaires assessing sleep (PSQI), physical activity (visual analogue scale), fatigue (MFI-20), anxiety, depression (HADS), and quality of life (EORTC QLQ-C30) within two weeks from starting treatment. Results The sample reported more sleep problems in comparison to the German population norm. The classification as good (ca 25%) or bad sleepers (ca 75%) showed less frequent physical activity (p = .04), higher fatigue (p = .032), anxiety (p = .003), depression (p = .011) and pain (p = .011) in bad sleepers. The mediation analysis revealed significant indirect effects of sleep on fatigue through physical activity habits. Conclusions This study highlights the combined action of sleep problems and physical activity on fatigue during the onset of induction chemotherapy. These two parameters could represent meaningful intervention targets to improve a patient’s status during chemotherapy. Trial registration The study was registered on the WHO trial register (DRKS00007824)

How the Direction of Screws Affects the Primary Stability of a Posterior Malleolus Osteosynthesis under Torsional Loading: A Biomechanical Study

Insufficient fixation of a posterior malleolus fracture (PM) can lead to posttraumatic complications such as osteoarthritis and chronic pain. The purpose of this biomechanical study was to test the hypothesis of whether the direction of PM screw fixation has an impact on the primary stability of osteosynthesis of a PM under torsional loading. PM fractures of 7 pairs human cadaveric lower leg specimens were stabilized with posterior to anterior (p.a.) or anterior to posterior (a.p.) screw fixation. Stability of the osteosynthesis was biomechanically tested using cyclic external torsional loading levels, in 2 Nm steps from 2 Nm up to 12 Nm, under constant monitoring with 3D ultrasonic marker (Zebris). The primary stability does not differ between both stabilizations ( p = 0.378) with a medium effect size (η 2 p = 0.065). The movement of the PM tends to be marginally greater for the osteosynthesis with a.p. screws than with p.a. screws. Whether a.p. screws or the alternative p.a. screw fixation is performed does not seem to have an influence on the primary stability of the osteosynthesis of the PM fixation under torsional loading. Although osteosynthesis from posterior seems to be more stable, the biomechanical results in the torsional test show quite equivalent stabilities. If there is no significant dislocation of the PM, a.p. screw fixation could be a minimally invasive but stable surgical strategy

Cellular immune response to acute exercise

Objectives: Exercise‐induced cellular mobilization might play a role in treatment and prevention of several diseases. However, little is known about the impact of different exercise modalities on immune cell mobilization and clinical cellular inflammation markers. Therefore, the present study aimed to investigate differences between acute endurance exercise (EE) and resistance exercise (RE) on cellular immune alterations. Methods: Twenty‐four healthy men conducted an acute EE (cycling at 60% of peak power output) and RE (five exercise machines at 70% of the one‐repetition maximum) session lasting 50 minutes in randomized order. Blood samples were collected before, after and one hour after exercise cessation. Outcomes included counts and proportions of leukocytes, neutrophils (NEUT), lymphocytes (LYM), LYM subsets, CD4/CD8 ratio, and the clinical cellular inflammation markers NEUT/LYM ratio (NLR), platelets/LYM ratio (PLR), and systemic immune inflammation index (SII). Results: Alterations in all outcomes were revealed except for CD8+ T cells, CD4/CD8 ratio, NLR, and PLR. EE induced a stronger cellular immune response and provoked alterations in more immune cell populations than RE. SII was altered only after EE. Conclusion: An acute EE session causes a stronger mobilization of immune cells than RE. Additionally, SII represents an integrative marker to depict immunological alterations

12-week combined strength and endurance exercise attenuates CD8+ T-cell differentiation and affects the kynurenine pathway in the elderly: a randomized controlled trial

Background: Age-related accumulation of highly differentiated CD8+ effector memory re-expressing CD45RA (EMRA) T-cells and disruption of the kynurenine (KYN) pathway are associated with chronic inflammation and the development of insulin resistance. In this study the aim was to investigate the effects of 12-week combined strength and endurance exercise on CD8+ T-cell differentiation and KYN pathway metabolites. Ninety-six elderly subjects (f/m, aged 50—70) were randomized to a control (CON) or exercise (EX) group. The EX group completed combined strength and endurance training twice weekly for one hour each time at an intensity of 60% of the one-repetition maximum for strength exercises and a perceived exertion of 15/20 for endurance exercises. The EX group was also randomly subdivided into two groups with or without a concomitant balanced diet intervention in order to examine additional effects besides exercise alone. Before and after the intervention phase, the proportions of CD8+ T-cell subsets and levels of KYN pathway metabolites in peripheral blood were determined. Results: The CD8+ EMRA T-cell subsets increased in the CON group but remained almost unchanged in the EX group (p =.02). Plasma levels of kynurenic acid (KA) increased in the EX group and decreased in the CON group (p =.03). Concomitant nutritional intervention resulted in lower levels of quinolinic acid (QA) compared with exercise alone (p =.03). Overall, there was a slight increase in the QA/KA ratio in the CON group, whereas it decreased in the EX group (p >.05). Conclusions: Combined strength and endurance training seems to be a suitable approach to attenuate CD8+ T-cell differentiation in the elderly and to redirect the KYN pathway towards KA. The clinical relevance of these effects needs further investigation

A mock circulation loop to test extracorporeal CO2 elimination setups

Background: Extracorporeal carbon dioxide removal (ECCO2R) is a promising yet limited researched therapy for hypercapnic respiratory failure in acute respiratory distress syndrome and exacerbated chronic obstructive pulmonary disease. Herein, we describe a new mock circuit that enables experimental ECCO2R research without animal models. In a second step, we use this model to investigate three experimental scenarios of ECCO2R: (I) the influence of hemoglobin concentration on CO2 removal. (II) a potentially portable ECCO2R that uses air instead of oxygen, (III) a low-flow ECCO2R that achieves effective CO2 clearance by recirculation and acidification of the limited blood volume of a small dual lumen cannula (such as a dialysis catheter). Results: With the presented ECCO2R mock, CO2 removal rates comparable to previous studies were obtained. The mock works with either fresh porcine blood or diluted expired human packed red blood cells. However, fresh porcine blood was preferred because of better handling and availability. In the second step of this work, hemoglobin concentration was identified as an important factor for CO2 removal. In the second scenario, an air-driven ECCO2R setup showed only a slightly lower CO2 wash-out than the same setup with pure oxygen as sweep gas. In the last scenario, the low-flow ECCO2R, the blood flow at the test membrane lung was successfully raised with a recirculation channel without the need to increase cannula flow. Low recirculation ratios resulted in increased efficiency, while high recirculation ratios caused slightly reduced CO2 removal rates. Acidification of the CO2 depleted blood in the recirculation channel caused an increase in CO2 removal rate. Conclusions: We demonstrate a simple and cost effective, yet powerful, “in-vitro” ECCO2R model that can be used as an alternative to animal experiments for many research scenarios. Moreover, in our approach parameters such as hemoglobin level can be modified more easily than in animal models

Influence of combined functional resistance and endurance exercise over 12 weeks on matrix metalloproteinase-2 serum concentration in persons with relapsing-remitting multiple sclerosis-a community-based randomized controlled trial

Background: The relevance of regular moderate to intense exercise for ameliorating psychomotor symptoms in persons with multiple sclerosis (pwMS) is becoming increasingly evident. Over the last two decades, emerging evidence from clinical studies and animal models indicate immune regulatory mechanisms in both periphery and the central nervous system that may underlie these beneficial effects. The integrity of the blood-brain barrier as the main structural interface between periphery and brain seems to play an important role in MS. Reducing the secretion of proteolytic matrix metalloproteinases (MMP), i.e. MMP-2, as disruptors of blood-brain barrier integrity could have profound implications for MS. Methods: In this two-Armed randomized controlled trial 64 participants with relapsing-remitting MS (RRMS) (EDSS 0-4.0) will be allocated to either an intervention group or a passive wait list control group. The intervention group will perform 60 min of combined functional resistance and endurance exercises 3x per week over a period of 12 weeks in a community-based and publicly available setting. Changes in serum concentration of MMP-2 will be the primary outcome. Secondary outcomes are numbers of immune cell subsets, soluble (anti-) inflammatory factors, physical capacity, cognitive performance, physical activity behavior, gait performance, and patient-reported outcomes. All outcome measures will be assessed at baseline and after week 12 with an additional blood sampling before, during and immediately after a single training session in week 6. Discussion: To our knowledge, this will be the first RCT to investigate both the acute and chronic effects of a community-based intense functional resistance and endurance exercise regimen in persons with RRMS. Combining analysis of biological and cognitive or psychological outcomes may provide a better understanding of the MS-specific symptomology. Trial registration: DRKS00017091; 05th of April, 2019; International Clinical Trials Registry Platform