Search

Your search keyword '"Zimmermann, Stefan"' showing total 1,778 results
Start Over Author "Zimmermann, Stefan" Publication Year Range Last 50 years
1,778 results on '"Zimmermann, Stefan"'

1. Advisory opinion of the AWMF Ad hoc Commission In-vitro Diagnostic Medical Devices regarding in-vitro diagnostic medical devices manufactured and used only within health institutions established in the Union according to Regulation (EU) 2017/746 (IVDR)

Author

Hoffmüller, Petra, Brüggemann, Monika, Eggermann, Thomas, Ghoreschi, Kamran, Haase, Detlef, Hofmann, Jörg, Hunfeld, Klaus-Peter, Koch, Katharina, Meisel, Christian, Michl, Patrick, Müller, Jens, Müller, Carsten, Rabenau, Holger F., Reinhardt, Dirk, Riemenschneider, Markus J., Sachs, Ulrich J., Sack, Ulrich, Stenzinger, Albrecht, Streichert, Thomas, von Neuhoff, Nils, Weichert, Wilko, Weinstock, Christof, Zimmermann, Stefan, Spitzenberger, Folker, and AWMF Ad hoc Commision In-vitro Diagnostic Medical Devices

Subjects
ivdr, laboratory-developed tests, in-house ivd, validation, performance evaluation, quality management, Medicine
Abstract

In view of the approaching application date of Regulation (EU) 2017/746 („IVDR“) and the resulting EU-wide, harmonized requirements for in-vitro diagnostic medical devices (IVD) manufactured and used within European health institutions, the Ad hoc Commission IVD of the German Association of the Scientific Medical Societies (AWMF) takes a national position on the details of the requirements and conditions related to the use of these IVD products.The Ad hoc Commission IVD emphasizes the relevance of examination procedures developed in medical laboratories, especially in the field of orphan diseases and new diagnostic markers. The IVDR sets an adequate regulatory framework for IVD manufactured and used within health institutions as long as these requirements are fulfilled with reliability and in accordance with the current state of the art in medical laboratory sciences. At the same time, the IVDR requirements have to be regarded under a pragmatic view and in accordance with the quality management systems approved within the different EU Member States. On the one hand, the mandatory requirements of the RiLiBÄK play an essential role in Germany. On the other hand, elements of voluntarily applicable international standards may support the fulfilment of product requirements for safety and performance according to Annex I of the IVDR. Both the complexity and possible solutions for the implementation of the IVDR requirements are discussed on the basis of examples such as the required documentation, performance evaluation and software validation.The Ad hoc Commission IVD recommends that, while aiming at a preferably EU-wide harmonized interpretation of the IVDR requirements, the flexibility in medical laboratory diagnostics necessary for patient care, including the use of IVD from in-house production, should be emphasized.

Published
2021
Full Text
View/download PDF

3. Gas Chromatography and Ion Mobility Spectrometry: A Perfect Match?

Author

Kirk, Ansgar T., Kobelt, Tim, Kueddelsmann, Maximilian J., and Zimmermann, Stefan

Subjects
Chemistry
Abstract

Over the past few decades, their outstanding sensitivity and quick response times have allowed ion mobility spectrometers (IMS) to become increasingly popular detectors for gas chromatographs (GC). In this manuscript, we discuss the basic operating principle of IMS, its resulting strengths and weaknesses, and why both perfectly align with the capabilities and requirements of gas chromatographs. This is combined with basic advice for setting up GC-IMS couplings and an outlook on some future developments., I ON MOBILITY SPECTROMETERS (IMS) separate and characterize ions based on their motion through a neutral gas under the influence of an electric field. Thus, one could shrewdly argue that [...]

Published
2024

6. Filmlandschaft

Author

Zimmermann, Stefan, Kühne, Olaf, Series Editor, Kinder, Sebastian, Series Editor, Schnur, Olaf, Series Editor, Weber, Florian, editor, Berr, Karsten, editor, and Jenal, Corinna, editor

Published
2024
Full Text
View/download PDF

11. Tumor-reactive T cell clonotype dynamics underlying clinical response to TIL therapy in melanoma

Author

Chiffelle, Johanna, Barras, David, Pétremand, Rémy, Orcurto, Angela, Bobisse, Sara, Arnaud, Marion, Auger, Aymeric, Rodrigo, Blanca Navarro, Ghisoni, Eleonora, Sauvage, Christophe, Saugy, Damien, Michel, Alexandra, Murgues, Baptiste, Fahr, Noémie, Imbimbo, Martina, Ochoa de Olza, Maria, Latifyan, Sofiya, Crespo, Isaac, Benedetti, Fabrizio, Genolet, Raphael, Queiroz, Lise, Schmidt, Julien, Homicsko, Krisztian, Zimmermann, Stefan, Michielin, Olivier, Bassani-Sternberg, Michal, Kandalaft, Lana E., Dafni, Urania, Corria-Osorio, Jesus, Trueb, Lionel, Dangaj Laniti, Denarda, Harari, Alexandre, and Coukos, George

Published
2024
Full Text
View/download PDF

40. High-Resolution Drift Tube Ion Mobility Spectrometer with Ultra-Fast Polarity Switching

Author

Hitzemann, Moritz, Kirk, Ansgar T., Lippmann, Martin, Nitschke, Alexander, Burckhardt, Olaf, Winkelholz, Jonas, and Zimmermann, Stefan

Abstract

Besides safety and security applications, ion mobility spectrometry (IMS) is increasingly used in other fields such as medicine, environmental monitoring and food quality analysis. However, some applications require gas chromatographic separation before analysis by IMS. Furthermore, different compounds in the sample may form positive or negative ions during ionization and therefore simultaneous detection of both ion polarities is highly beneficial to avoid two chromatographic runs of the same sample. This can be achieved by ultra-fast polarity switching of a single drift tube IMS, allowing for quasi-simultaneous detection of both ion polarities. By using a ramped aperture voltage during the switching process, we overcome the issue of excessive displacement currents at the detector during polarity switching, which usually lead to overdriving the output signal of the high-gain transimpedance amplifier. Furthermore, mechanical aperture grid oscillations caused by polarity switching were also reduced through the ramped aperture voltage. This enables a polarity switching time of only 7 ms at a drift voltage of 8 kV and a drift length of 103 mm, leading to a high resolving power of RP= 117. Requiring 50 ms to acquire a pair of positive and negative spectrum, the IMS achieves an acquisition rate of 20 Hz. It reaches limits of detection of 20 pptvfor dimethyl methylphosphonate and 40 pptvfor methyl salicylate. For demonstration, different hop varieties were investigated and could be clearly differentiated by considering both, the positive and negative spectra.

Published
2024
Full Text
View/download PDF

42. Coated Blade Spray Ion Mobility Spectrometry

Author

Thoben, Christian, Stadtler, Jannie J., Simon, Paul R., Raddatz, Christian-Robert, Sehlmeyer, Merle, Zimmermann, Stefan, Thoben, Christian, Stadtler, Jannie J., Simon, Paul R., Raddatz, Christian-Robert, Sehlmeyer, Merle, and Zimmermann, Stefan

Abstract

Coated blade spray (CBS) is a microextraction technology with blades that serve as both the extraction device and the electrospray ionization (ESI) emitter. CBS is designed for easy and rapid extraction of analytes in complex matrices as well as ESI directly from the blade. The technology selectively enriches the components of interest on a coated metal blade. The coating consists of a selective polymer. So far, CBS has only been coupled with mass spectrometry but never with ion mobility spectrometry (IMS), where ions are separated and detected based on their ion mobility in a drift gas under the influence of an electric field, while instrumentation is compact and easy to operate so that the advantages of CBS can be particularly well exploited. Therefore, this work focuses on coupling CBS with our previously described ESI-IMS. The ion mobility spectrometer has a drift length of only 75 mm and provides a high resolving power of RP = 100. In this work, preliminary measurements of CBS-IMS are presented. In particular, the detection of benzodiazepines and ketamine in drinks and the pesticide isoproturon in water samples is shown to demonstrate the feasibility of CBS-IMS.

Published
2024

43. Ten-Year Minimum Follow-up Study of First Metatarsophalangeal Joint Fusion in Young vs Old Patients

Author

Scheurer, Fabrice; https://orcid.org/0000-0002-8789-4486, Zimmermann, Stefan M; https://orcid.org/0000-0002-1892-6624, Fischer, Philipp, Wirth, Stephan H; https://orcid.org/0000-0002-6356-5338, Beeler, Silvan; https://orcid.org/0000-0002-0928-7795, Viehöfer, Arnd F; https://orcid.org/0000-0003-3448-8625, Scheurer, Fabrice; https://orcid.org/0000-0002-8789-4486, Zimmermann, Stefan M; https://orcid.org/0000-0002-1892-6624, Fischer, Philipp, Wirth, Stephan H; https://orcid.org/0000-0002-6356-5338, Beeler, Silvan; https://orcid.org/0000-0002-0928-7795, and Viehöfer, Arnd F; https://orcid.org/0000-0003-3448-8625

Abstract

BACKGROUND Painful degenerative joint disease (DJD) of the first metatarsophalangeal joint (MTP I), or hallux rigidus, mainly occurs in later stages of life. For end-stage hallux rigidus, MTP I arthrodesis is considered the gold standard. As young and active patients are affected considerably less frequently, it currently remains unclear, whether they benefit to the same extent. We hypothesized that MTP I arthrodesis in younger patients would lead to an inferior outcome with decreased rates of overall with lower rates of patient postoperative pain and function compared to an older cohort. METHODS All patients aged <50 y ears who underwent MTP I arthrodesis at our institution between 1995 and 2012 were included in this study. This group was then matched and compared with a group of patients aged >60 years. Minimum follow-up was 10 years. Outcome measures were Tegner activity score (TAS), a "Virtual Tegner activity score" (VTAS), the visual analog scale (VAS), and the Foot Function index (FFI). RESULTS Sixty-one MTP I fusions (n = 28 young, n = 33 old) in 46 patients were included in our study at an average of 14 years after surgery. Younger patients experienced significantly more pain relief as reflected by changes in VAS and FFI Pain subscale scores. No difference in functional outcomes was found with change in the FFI function subscale or in the ability to have desired functional outcomes using the ratio of TAS to VTAS. Revision rate did not differ between the two groups apart from hardware removal, which was significantly more likely in the younger group. CONCLUSION In patients below the age of 50 years with end-stage DJD of the first metatarsal joint, MTP I arthrodesis not only yielded highly satisfactory postoperative results at least equal outcome compared to an older cohort of patients aged >60 years at an average 14 years' follow-up. Based on these findings, we consider first metatarsal joint fusion even for young patients is a valid option to treat end-stage

Published
2024

50. Clinical and genomic features of Mycobacterium avium complex: a multi-national European study.

Author

Wetzstein, Nils, Diricks, Margo, Anton, Thomas B., Andres, Sönke, Kuhns, Martin, Kohl, Thomas A., Schwarz, Carsten, Lewin, Astrid, Kehrmann, Jan, Kahl, Barbara C., Schmidt, Annika, Zimmermann, Stefan, Jansson, Moritz K., Baron, Sophie A., Schulthess, Bettina, Hogardt, Michael, Friesen, Inna, Niemann, Stefan, and Wichelhaus, Thomas A.

Subjects
MYCOBACTERIUM avium, WHOLE genome sequencing, MYCOBACTERIA, PLASMIDS, ARACHNOID cysts
Abstract

Background: The Mycobacterium avium complex (MAC) comprises the most frequent non-tuberculous mycobacteria (NTM) in Central Europe and currently includes twelve species. M. avium (MAV), M. intracellulare subsp. intracellulare (MINT), and M. intracellulare subsp. chimaera (MCH) are clinically most relevant. However, the population structure and genomic landscape of MAC linked with potential pathobiological differences remain little investigated. Methods: Whole genome sequencing (WGS) was performed on a multi-national set of MAC isolates from Germany, France, and Switzerland. Phylogenetic analysis was conducted, as well as plasmids, resistance, and virulence genes predicted from WGS data. Data was set into a global context with publicly available sequences. Finally, detailed clinical characteristics were associated with genomic data in a subset of the cohort. Results: Overall, 610 isolates from 465 patients were included. The majority could be assigned to MAV (n = 386), MCH (n = 111), and MINT (n = 77). We demonstrate clustering with less than 12 SNPs distance of isolates obtained from different patients in all major MAC species and the identification of trans-European or even trans-continental clusters when set into relation with 1307 public sequences. However, none of our MCH isolates clustered closely with the heater-cooler unit outbreak strain Zuerich-1. Known plasmids were detected in MAV (325/1076, 30.2%), MINT (62/327, 19.0%), and almost all MCH-isolates (457/463, 98.7%). Predicted resistance to aminoglycosides or macrolides was rare. Overall, there was no direct link between phylogenomic grouping and clinical manifestations, but MCH and MINT were rarely found in patients with extra-pulmonary disease (OR 0.12 95% CI 0.04–0.28, p < 0.001 and OR 0.11 95% CI 0.02–0.4, p = 0.004, respectively) and MCH was negatively associated with fulfillment of the ATS criteria when isolated from respiratory samples (OR 0.28 95% CI 0.09-0.7, p = 0.011). With 14 out of 43 patients with available serial isolates, co-infections or co-colonizations with different strains or even species of the MAC were frequent (32.6%). Conclusions: This study demonstrates clustering and the presence of plasmids in a large proportion of MAC isolates in Europe and in a global context. Future studies need to urgently define potential ways of transmission of MAC isolates and the potential involvement of plasmids in virulence. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results