German S3 guideline "actinic keratosis and cutaneous squamous cell carcinoma" – long version of the update 2023

Actinic keratosis (AK) are common lesions in light-skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence-based framework for clinical decision making, the guideline “actinic keratosis and cutaneous squamous cell carcinoma” was updated and expanded by the topics cutanepus squamous cell carcinoma in situ (Bowen’s disease) and actinic cheilitis. This guideline was developed at the highest evidence level (S3) and is aimed at dermatologists, general practitioners, ear nose and throat specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office-based settings, as well as other medical specialties, policy makers and insurance funds involved in the diagnosis and treatment of patients with AK and cSCC

New experimental methods of charge density determination

# Inhaltsverzeichnis Titel i Inhaltsverzeichnis iii I Grundlagen 1 1 Einleitung 3 2 Theoretische Grundlagen 7 3 Experimentelle Grundlagen 29 II Aminosäuren 37 4 Präparation und Messung 39 5 Asparagin 43 6 Glutaminsäure 59 7 Lysin 73 8 Prolin 87 9 Serin 103 10 Valin 121 11 Vergleichende Diskussion der Aminosäuren 133 III Das Antithrombotikum Terbogrel 145 12 Terbogrel 147 Zusammenfassung 171 Summary 173 Literaturverzeichnis 175 Publikationen 183 A Parametertabellen 187# Zusammenfassung Im Rahmen der vorliegenden Dissertation konnten wichtige methodische experimentelle Aspekte zur Entwicklung der Ladungsdichtebestimmung beigetragen werden. Erstmalig konnte der Nachweis erbracht werden, daß mit der Kombination Synchrotronprimärstrahlung/CCD-Flächendetektion elektronische Eigenschaften einer Verbindung in kurzer Zeit zugänglich sind, deren Genauigkeit vergleichbar oder höher ist als jene, die mit Punktdetektion erhalten wurden und wochenlange Meßzeiten erforderten, was bis zu diesem Zeitpunkt in Frage gestellt wurde. Dieses Ergebnis eröffnete die Perspektive, einerseits vergleichende Studien an einer Reihe von Verbindungen einer verwandten Klasse von Molekülen vorzunehmen, andererseits erschien es möglich, Ladungsdichtebestimmungen auch an größeren biologisch relevanten Verbindungen durchzuführen. In der vorliegenden Arbeit wurden beide Perspektiven verfolgt. An sechs Aminosäuren wurden umfangreiche Ladungsdichtestudien durchgeführt, die eine vollständige topologische Analyse der Elektronendichte unter Einbeziehung intra- und intermolekularer Wechselwirkungen beinhalteten. Für diese Verbindungsklasse wurde ein hoher Grad an Reproduzierbarkeit und Transferierbarkeit von atomaren und Gruppeneigenschaften gefunden deren Varianz sogar noch geringer ist, als jene aus ab initio-Rechnungen mit unterschiedlichen Methoden und Basissätzen. Somit wurde ein experimenteller Beitrag zur Unterstützung der Quantentheorie "Atoms in Molecules" geleistet. Zudem konnten erstmalig am Beispiel der experimentellen dreidimensionalen Laplacefunktion feine Ladungsdichtereorganisationen aufgrund schwacher intermolekularer Wechselwirkungen visualisiert werden und somit Richtungen, in denen chemische Wechselwirkungen und intermolekulare Erkennungsprozesse favorisiert sind, bestimmt und charakterisiert werden. Mit dem Antithrombotikum Terbogrel konnte eine größere biologisch und pharmakologisch relevante Verbindung ebenfalls mit hoher Genauigkeit elektronisch charakterisiert werden. Zudem konnte am Beispiel dieses Wirkstoffes gezeigt werden, daß sogar eine konventionelle Röntgenquelle zusammen mit flächenhafter Detektion, wie sie heutzutage zunehmend zur Standardausstattung von Forschungslaboratorien gehört, für die genaue experimentelle Ladungsdichtebestimmung größerer Moleküle geeignet ist und somit diese Methode einem größeren Nutzerkreis zugänglich wird. So konnten dank schneller Experimente, deren Zeitbedarf erheblich unter demjenigen von vergleichbaren ab initio-Rechnungen liegen, quantitative Ergebnisse auf elektronischem Niveau erhalten werden, wobei eine Zunahme an Auflösung und Genauigkeit erzielt werden konnte. Neben den hier eingeführten experimentellen Beiträgen zur Entwicklung der Ladungsdichtebestimmung trägt die vorliegende Arbeit somit auch zum Molecular Modelling und Drug Design bei.# Summary Within the framework of the present dissertation important methodological and experimental aspects could be contributed to the development of charge density determination. For the first time it could be proven that with the combination of synchrotron primary radiation/CCD area detection electronic properties are accessible in a short time and that the accuracy of these properties is comparable or even superior to that obtained with point detection, requiring measurement times of several weeks. This has been doubted so far. This result opened the perspective on the one hand to do comparable studies on a class of related compounds, on the other hand it seemed possible to perform charge density studies on larger systems of biological importance. In this thesis both perspectives were followed. On six amino acids extensive charge density studies were performed including a complete topological analysis of the charge density of all the intra- and intermolecular interactions. For this class of compounds a high degree of reproducability and transferability of atomic and group properties could be found. The variance of these properties is even less than the one found when using ab initio calculations with different methods and basis sets. Therefore an experimental contribution to support the quantum theory of "Atoms in Molecules" was given. For the first time fine charge density reorganizations due to weak intermolecular interactions could be visualized with the help of the threedimensional experimental Laplacian function and therefore directions in which chemical interactions are favoured could be located and characterized. With the antithrombotic drug Terbogrel it was shown that a larger compound of biological relevance could be characterized electronically with high accuracy. In addition, taking the example of this drug, it could be shown that even a conventional X-ray source combined with area detection, which is getting nowadays common laboratory equipment, is suitable for charge density determination of larger molecules und thus opens the method for a larger community. Quantitative results on the electronic level could be obtained due to fast experiments, whose time consumption is far less than that of comparable ab initio calculations. An enhancement of resolution and accuracy could be reached. Besides the experimental contribution to the development in charge density determination introduced here this work also contributes to the fields of molecular modelling and drug design

Charge Density and Experimental Electrostatic Potentials of Two Penicillin Derivatives

International audienceTwo penicillin derivatives, the active penamecillin and the inactive penamecillin-1beta-sulfoxide, were used to study the relationship between their charge density and their activity. Single crystals of both compounds were measured at the synchrotron beamline F1 at the HASYLAB/DESY, at 100 K and up to resolutions of around 0.4 A. Experimental charge densities were obtained by using the Hansen-Coppens multipole formalism. The cleavage of the amide bond in the beta-lactam ring is of paramount importance in the mechanism of action of penicillins. Topological analysis of this bond in terms of Bader's AIM theory showed that its strength is equal in both compounds; therefore a direct influence of bond strength on the activity can be ruled out. However, the two derivatives differ significantly in their experimental electrostatic potentials. These differences are discussed and provide further insight into the chemistry and activity of penicillins

Topological Properties of the Peptide Bond in Glycyl-L-threonine Dihydrate Based on a Fast Synchrotron/CCD-Diffraction Experiment at 100 K

The charge density of glycyl-L-threonine dihydrate is extracted from a synchrotron data set of 98 405 reflections collected at 100 K with a Bruker CCD area detector up to a resolution of d=0.38 Å (sinθ/λ=1.32 Å−1). The data are interpreted in terms of the “rigid pseudoatom” model. The topology of the experimental density is analyzed and compared with the topology obtained experimentally for the constituting amino acids and to that derived from Hartree-Fock calculations for the isolated molecule. All critical points of the electron density at the covalent and hydrogen bonds, as well as those of the Laplacian, were located, thereby deriving quantitative topological data for the peptide and side chain bonds. Bond topological indices in the dipeptide compare well with those of the corresponding bonds in the building amino acids, thus suggesting transferability of electronic properties of atoms and functional groups when these are derived by Bader's partitioning. Discrepancies between theoretical and experimental results could be attributed to crystal field effects

Schnelle Experimente zur Ladungsdichtebestimmung: topologische Analyse und elektrostatisches Potential der Aminosäuren L-Asn, DL-Glu, DL-Ser und L-Thr

Synchrotronstrahlung und CCD-Detektion ermöglichten schnelle Beugungsexperimente, mit denen genaue Ladungsdichteverteilungen von Aminosäuren hergeleitet werden konnten. Ihre topologische Analyse (das Bild zeigt die negative Laplace-Funktion von DL-Serin in der Ebene der Carboxylatgruppe) liefert für die Aminosäuren nicht nur vergleichbare Informationen über intramolekulare, sondern auch über schwache intermolekulare Wechselwirkungen

Validation of X-ray Wavefunction Refinement

In this work, the quality of the electron density in crystals reconstructed by the multipolar model (MM) and by X-ray wavefunction refinement (XWR) is tested on a set of high-resolution X-ray diffraction data sets of four amino acids and six tripeptides. It results in the first thorough validation of XWR. Agreement statistics, figures of merit, residual- and deformation-density maps, as well as atomic displacement parameters are used to measure the quality of the reconstruction relative to the measured structure factors. Topological analysis of the reconstructed density is carried out to obtain atomic and bond-topological properties, which are subsequently compared to the values derived from benchmarking periodic DFT geometry optimizations. XWR is simultaneously in better agreement than the MM with both benchmarking theory and the measured diffraction pattern. In particular, the obvious problems with the description of polar bonds in the MM are significantly reduced by using XWR. Similarly, modeling of electron density in the vicinity of hydrogen atoms with XWR is visibly improved

Communication between the ERRalpha homodimer interface and the PGC-1alpha binding surface via the helix 8-9 loop.

International audienceAlthough structural studies on the ligand-binding domain (LBD) have established the general mode of nuclear receptor (NR)/coactivator interaction, determinants of binding specificity are only partially understood. The LBD of estrogen receptor-alpha (ERalpha), for example, interacts only with a region of peroxisome proliferator-activated receptor coactivator (PGC)-1alpha, which contains the canonical LXXLL motif (NR box2), whereas the LBD of estrogen-related receptor-alpha (ERRalpha) also binds efficiently an untypical, LXXYL-containing region (NR box3) of PGC-1alpha. Surprisingly, in a previous structural study, the ERalpha LBD has been observed to bind NR box3 of transcriptional intermediary factor (TIF)-2 untypically via LXXYL, whereas the ERRalpha LBD binds this region of TIF-2 only poorly. Here we present a new crystal structure of the ERRalpha LBD in complex with a PGC-1alpha box3 peptide. In this structure, residues N-terminal of the PGC-1alpha LXXYL motif formed contacts with helix 4, the loop connecting helices 8 and 9, and with the C terminus of the ERRalpha LBD. Interaction studies using wild-type and mutant PGC-1alpha and ERRalpha showed that these contacts are functionally relevant and are required for efficient ERRalpha/PGC-1alpha interaction. Furthermore, a structure comparison between ERRalpha and ERalpha and mutation analyses provided evidence that the helix 8-9 loop, which differs significantly in both nuclear receptors, is a major determinant of coactivator binding specificity. Finally, our results revealed that in ERRalpha the helix 8-9 loop allosterically links the LBD homodimer interface with the coactivator cleft, thus providing a plausible explanation for distinct PGC-1alpha binding to ERRalpha monomers and homodimers

S3 guideline for actinic keratosis and cutaneous squamous cell carcinoma – short version, part 1: diagnosis, interventions for actinic keratoses, care structures and quality‐of‐care indicators

Actinic keratoses (AK) are common lesions in light‐skinned individuals that can potentially progress to cutaneous squamous cell carcinoma (cSCC). Both conditions may be associated with significant morbidity and constitute a major disease burden, especially among the elderly. To establish an evidence‐based framework for clinical decision making, the guideline “actinic keratosis and cutaneous squamous cell carcinoma” was developed using the highest level of methodology (S3) according to regulations issued by the Association of Scientific Medical Societies in Germany (AWMF). The guideline is aimed at dermatologists, general practitioners, ENT specialists, surgeons, oncologists, radiologists and radiation oncologists in hospitals and office‐based settings as well as other medical specialties involved in the diagnosis and treatment of patients with AK and cSCC. The guideline is also aimed at affected patients, their relatives, policy makers and insurance funds. In the first part, we will address aspects relating to diagnosis, interventions for AK, care structures and quality‐of‐care indicators.Peer Reviewe