@article{DeutschmannRoggenbuckSchieracketal.2020, author = {Deutschmann, Claudia and Roggenbuck, Dirk and Schierack, Peter and R{\"o}diger, Stefan}, title = {Autoantibody testing by enzyme-linked immunosorbent assay-a case in which the solid phase decides on success and failure}, series = {Heliyon}, volume = {6}, journal = {Heliyon}, number = {1}, publisher = {Elsevier}, address = {London [u.a.]}, issn = {2405-8440}, doi = {10.1016/j.heliyon.2020.e03270}, pages = {6}, year = {2020}, abstract = {Background: The enzyme-linked immunosorbent assay (ELISA) is an indispensable tool for clinical diagnostics to identify or differentiate diseases such as autoimmune illnesses, but also to monitor their progression or control the efficacy of drugs. One use case of ELISA is to differentiate between different states (e.g. healthy vs. diseased). Another goal is to quantitatively assess the biomarker in question, like autoantibodies. Thus, the ELISA technology is used for the discovery and verification of new autoantibodies, too. Of key interest, however, is the development of immunoassays for the sensitive and specific detection of such biomarkers at early disease stages. Therefore, users have to deal with many parameters, such as buffer systems or antigen-autoantibody interactions, to successfully establish an ELISA. Often, fine-tuning like testing of several blocking substances is performed to yield high signal-to-noise ratios.
Methods: We developed an ELISA to detect IgA and IgG autoantibodies against chitinase-3-like protein 1 (CHI3L1), a newly identified autoantigen in inflammatory bowel disease (IBD), in the serum of control and disease groups (n = 23, respectively). Microwell plates with different surface modifications (PolySorp and MaxiSorp coating) were tested to detect reproducibility problems.
Results: We found a significant impact of the surface properties of the microwell plates. IgA antibody reactivity was significantly lower, since it was in the range of background noise, when measured on MaxiSorp coated plates (p < 0.0001). The IgG antibody reactivity did not differ on the diverse plates, but the plate surface had a significant influence on the test result (p = 0.0005).
Conclusion: With this report, we want to draw readers' attention to the properties of solid phases and their effects on the detection of autoantibodies by ELISA. We want to sensitize the reader to the fact that the choice of the wrong plate can lead to a false negative test result, which in turn has serious consequences for the discovery of autoantibodies.}, language = {en} } @phdthesis{Mueller2008, author = {M{\"u}ller, Steffen}, title = {Die belastungsspezifische neuromuskul{\"a}re Antwort bei Athleten mit Tendinopathie der Achilles- oder Patellarsehne : Analysen der funktionalen und therapeutischen Effekte eines sensomotorischen Trainings}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-940793-18-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16454}, school = {Universit{\"a}t Potsdam}, pages = {II, 137}, year = {2008}, abstract = {Tendinopathien der Achilles- oder Patellarsehne sind h{\"a}ufig in Sportarten mit zahlreichen repetitiven Belastungen im Dehnungs-Verk{\"u}rzungs-Zyklus der unteren Extremit{\"a}t zu finden. Sowohl eine m{\"o}glicherweise alterierte belastungsspezifische neuromuskul{\"a}re Antwort (NMA), als auch funktional begr{\"u}ndete Therapiemaßnahmen mit m{\"o}glichen positiven Effekten sind aktuell ungekl{\"a}rt. Ziel der Arbeit war deshalb die Untersuchung der belastungsspezifischen neuromuskul{\"a}ren Antwort bei Athleten mit Tendinopathie der Achilles- oder Patellarsehne im Vergleich zu beschwerdefreien Athleten. Zus{\"a}tzlich sollten m{\"o}gliche funktionale und therapeutische Effekte eines sensomotorischen Trainings im randomisierten, kontrollierten und prospektiven Studiendesign {\"u}berpr{\"u}ft werden. 51 Sportler mit unilateraler Tendinopathie (Achilles-/Patellarsehne n = 35/16) und 33 gesunde Sportler wurden zur Beurteilung der belastungsspezifischen neuromuskul{\"a}ren Antwort eingeschlossen. Zur Kl{\"a}rung der Effekte eines sensomotorischen Trainings im L{\"a}ngsschnitt konnten 26 Sportler mit Tendinopathie randomisiert zu einer Kontrollgruppe (n = 14) und einer Therapiegruppe mit sensomotorischem Training (n = 12) zugeordnet werden. Nach einer ersten biomechanischen Messung M1 (Belastungssituationen: Lauf-, Stabilisations-, Kraftbelastung) und der Erhebung der subjektiven Schmerzsymptomatik folgte eine 8-w{\"o}chige Therapiephase mit einer abschließenden Re-Test-Messung M2 identisch zu M1. Das sensomotorische Training war auf die gesamte untere Extremit{\"a}t ausgerichtet und wurde nach Einweisung regelm{\"a}ßig kontrolliert. Die Erfassung der NMA erfolgte {\"u}ber die Quantifizierung der muskul{\"a}ren Aktivit{\"a}t (EMG). Zus{\"a}tzlich wurde die Kinetik (z.B. Maximalkraft) belastungsspezifisch erfasst. Eine reduzierte NMA konnte f{\"u}r die Sportler mit Tendinopathie {\"u}ber ver{\"a}nderte EMG-Zeit- und Amplitudenmessgr{\"o}ßen, eine reduzierte aktive Stabilisationsf{\"a}higkeit und Maximalkraft (p < 0,05) nachgewiesen werden. In Abh{\"a}ngigkeit der Lokalisation (Achilles-/Patellarsehen) bzw. der Seite (Beschwerdeseite/gesunde Seite) ergaben sich keine relevanten Differenzen. Das sensomotorische Training zeigte eine Optimierung der NMA (z.B. erh{\"o}hte Maximalkraft) bei Tendinopathie der Achilles- oder Patellarsehne. Die {\"U}berpr{\"u}fung der Beschwerdesymptomatik wies in allen Schmerz-Scores nach der Therapie reduzierte Werte und damit einen positiven therapeutischen Effekt gegen{\"u}ber der Kontrollgruppe auf. Zusammenfassend kann eine systematisch reduzierte NMA bei Lauf-, Stabilisations- und Kraftbelastung der Sportler mit Tendinopathie nachgewiesen werden. Das sensomotorische Training ist funktional und therapeutisch als effiziente Therapiemaßnahme zu erachten.}, language = {de} } @misc{BittmannDechAehleetal.2020, author = {Bittmann, Frank and Dech, Silas and Aehle, Markus and Schaefer, Laura}, title = {Manual Muscle Testing—Force Profiles and Their Reproducibility}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {671}, issn = {1866-8364}, doi = {10.25932/publishup-48561}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-485612}, pages = {32}, year = {2020}, abstract = {The manual muscle test (MMT) is a flexible diagnostic tool, which is used in many disciplines, applied in several ways. The main problem is the subjectivity of the test. The MMT in the version of a "break test" depends on the tester's force rise and the patient's ability to resist the applied force. As a first step, the investigation of the reproducibility of the testers' force profile is required for valid application. The study examined the force profiles of n = 29 testers (n = 9 experiences (Exp), n = 8 little experienced (LitExp), n = 12 beginners (Beg)). The testers performed 10 MMTs according to the test of hip flexors, but against a fixed leg to exclude the patient's reaction. A handheld device recorded the temporal course of the applied force. The results show significant differences between Exp and Beg concerning the starting force (padj = 0.029), the ratio of starting to maximum force (padj = 0.005) and the normalized mean Euclidean distances between the 10 trials (padj = 0.015). The slope is significantly higher in Exp vs. LitExp (p = 0.006) and Beg (p = 0.005). The results also indicate that experienced testers show inter-tester differences and partly even a low intra-tester reproducibility. This highlights the necessity of an objective MMT-assessment. Furthermore, an agreement on a standardized force profile is required. A suggestion for this is given.}, language = {en} } @article{BittmannDechAehleetal.2020, author = {Bittmann, Frank and Dech, Silas and Aehle, Markus and Schaefer, Laura}, title = {Manual Muscle Testing—Force Profiles and Their Reproducibility}, series = {Diagnostics}, volume = {10}, journal = {Diagnostics}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {2075-4418}, doi = {10.3390/diagnostics10120996}, pages = {30}, year = {2020}, abstract = {The manual muscle test (MMT) is a flexible diagnostic tool, which is used in many disciplines, applied in several ways. The main problem is the subjectivity of the test. The MMT in the version of a "break test" depends on the tester's force rise and the patient's ability to resist the applied force. As a first step, the investigation of the reproducibility of the testers' force profile is required for valid application. The study examined the force profiles of n = 29 testers (n = 9 experiences (Exp), n = 8 little experienced (LitExp), n = 12 beginners (Beg)). The testers performed 10 MMTs according to the test of hip flexors, but against a fixed leg to exclude the patient's reaction. A handheld device recorded the temporal course of the applied force. The results show significant differences between Exp and Beg concerning the starting force (padj = 0.029), the ratio of starting to maximum force (padj = 0.005) and the normalized mean Euclidean distances between the 10 trials (padj = 0.015). The slope is significantly higher in Exp vs. LitExp (p = 0.006) and Beg (p = 0.005). The results also indicate that experienced testers show inter-tester differences and partly even a low intra-tester reproducibility. This highlights the necessity of an objective MMT-assessment. Furthermore, an agreement on a standardized force profile is required. A suggestion for this is given.}, language = {en} } @article{RectorIntziegianniMuelleretal.2017, author = {Rector, Michael V. and Intziegianni, Konstantina and M{\"u}ller, Steffen and Mayer, Frank and Cassel, Michael}, title = {Reproducibility of an ankle joint rotation correction method for assessment of Achilles tendon elongation}, series = {Isokinetics and exercise science : official journal of the European Isokinetic Society}, volume = {25}, journal = {Isokinetics and exercise science : official journal of the European Isokinetic Society}, number = {1}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0959-3020}, doi = {10.3233/IES-160644}, pages = {47 -- 52}, year = {2017}, abstract = {BACKGROUND: The Achilles tendon (AT) requires optimal material and mechanical properties to function properly. Calculation of these properties depends on accurate measurement of input parameters (i.e. tendon elongation). However, the measurement of AT elongation with ultrasound during maximum voluntary isometric contraction (MVIC) is overestimated by ankle joint rotation (AJR). Methods to correct the influence of this rotation on AT elongation exist, yet their reproducibility in clinical settings is unknown. OBJECTIVE: To evaluate the test-retest reproducibility of AT elongation during MVIC after AJR correction. METHODS: Ten participants attended test and retest measurements where they performed plantar-flexion MVIC on a dynamometer. Simultaneously, ultrasound recorded AT elongation as the displacement of the medial gastrocnemius-myotendinous junction, while an electrogoniometer measured AJR. The ankle was then passively rotated to the AJR achieved during MVIC and AT elongation again determined. Elongation was corrected by subtracting this passive AT elongation from the total AT elongation during MVIC. Reproducibility was evaluated using ICC (2.1), test-retest variability (TRV, \%), Bland-Altman analyses (Bias +/- LoA [1.96*SD]) and standard error of the measurement (SEM). RESULTS: Corrected AT elongation reproducibility exhibited an ICC = 0.79, SEM = 0.2 cm and TRV = 20 +/- 19\%. Bias +/- LoA were determined to be 0.0 +/- 0.8 cm. CONCLUSIONS: Using this ultrasound and electrogoniometer-based method, corrected AT elongation can be assessed reproducibly.}, language = {en} } @article{SchenkEichelmannSchulzeetal.2019, author = {Schenk, Matthew and Eichelmann, Fabian and Schulze, Matthias Bernd and Rudovich, Natalia and Pfeiffer, Andreas F. H. and di Giuseppe, Romina and B{\"o}ing, Heiner and Aleksandrova, Krasimira}, title = {Reproducibility of novel immune-inflammatory biomarkers over 4 months}, series = {Biomarkers in medicine}, volume = {13}, journal = {Biomarkers in medicine}, number = {8}, publisher = {Future Medicine}, address = {London}, issn = {1752-0363}, doi = {10.2217/bmm-2018-0351}, pages = {639 -- 648}, year = {2019}, abstract = {Aim: Assessment of the feasibility and reliability of immune-inflammatory biomarker measurements. Methods: The following biomarkers were assessed in 207 predominantly healthy participants at baseline and after 4 months: MMF, TGF-beta, suPAR and clusterin. Results: Intraclass correlation coefficients (95\% CIs) ranged from good for TGF-beta (0.75 [95\% CI: 0.33-0.90]) to excellent for MMF (0.81 [95\% CI: 0.64-0.90]), clusterin (0.83 [95\% CI: 0.78-0.87]) and suPAR (0.91 [95\% CI: 0.88-0.93]). Measurement of TGF-beta was challenged by the large number of values below the detection limit. Conclusion: Single measurements of suPAR, clusterin and MMF could serve as feasible and reliable biomarkers of immune-inflammatory pathways in biomedical research.}, language = {en} } @article{ReineckeTrautmannWageneretal.2022, author = {Reinecke, Robert and Trautmann, Tim and Wagener, Thorsten and Sch{\"u}ler, Katja}, title = {The critical need to foster computational reproducibility}, series = {Environmental research letters}, volume = {17}, journal = {Environmental research letters}, number = {4}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1748-9326}, doi = {10.1088/1748-9326/ac5cf8}, pages = {5}, year = {2022}, language = {en} } @article{IntziegianniCasselKoenigetal.2015, author = {Intziegianni, Konstantina and Cassel, Michael and K{\"o}nig, Niklas and M{\"u}ller, Steffen and Fr{\"o}hlich, Katja and Mayer, Frank}, title = {Ultrasonography for the assessment of the structural properties of the Achilles tendon in asymptomatic individuals: An intra-rater reproducibility study}, series = {Isokinetics and exercise science : official journal of the European Isokinetic Society}, volume = {23}, journal = {Isokinetics and exercise science : official journal of the European Isokinetic Society}, number = {4}, publisher = {IOS Press}, address = {Amsterdam}, issn = {0959-3020}, doi = {10.3233/IES-150586}, pages = {263 -- 270}, year = {2015}, abstract = {BACKGROUND: Reproducible measurements of tendon structural properties are a prerequisite for accurate diagnosis of tendon disorders and for determination of their mechanical properties. Despite the widely used application of Ultrasonography (US) in musculoskeletal assessment, its operator dependency and lack of standardization influences the consistency of the measurement. OBJECTIVE: To evaluate the intra-rater reproducibility of a standardized US method assessing the structural properties of the Achilles tendon (AT). METHODS: Sixteen asymptomatic participants were positioned prone on an isokinetic dynamometer with the knee extended and ankle at 90. flexion. US was used to assess AT-length, cross-sectional area (CSA), and AT-elongation during isometric plantarflexion contraction. The intra-rater reproducibility was assessed by ICC (2.1), Test-Retest Variability (TRV, \%), Bland-Altman analyses (Bias +/- LoA [1.96*SD]), and Standard-Error of Measurement (SEM). RESULTS: Measurements of AT-length demonstrated an ICC of 0.93, TRV of 4.5 +/- 3.9\%, Bias +/- LoA of -2.8 +/- 25.0 mm and SEM of 6.6 mm. AT-CSA showed an ICC of 0.79, TRV of 8.7 +/- 9.6\%, Bias +/- LoA of 1.7 +/- 19.4 mm(2) and SEM of 5.3 mm(2). AT-elongation revealed an ICC of 0.92, TRV of 12.9 +/- 8.9\%, Bias +/- LoA of 0.3 +/- 5.7 mm and SEM of 1.5 mm. CONCLUSIONS: The presented methodology allows a reproducible assessment of Achilles tendon structural properties when performed by a single rater.}, language = {en} }