Etablierung eines Nachweissystems zur Quantifizierung von Cytochrom P450 Enzymen in der menschlichen Leber

Den Abbauprozessen von Fremdstoffen kommt vor allem in der pharmazeutischen Industrie großes Interesse zu. Die größtenteils auf mRNA-Expressionsstudien und Enzymaktivitätstest beruhende Erforschung des Fremdstoffmetabolismus kann durch die in dieser Arbeit entwickelte Quantifizierungsstrategie um die Information des Proteingehalts ergänzt werden. Der Konzentrationen der Cytochrom P450 Enzyme stellen einen wichtigen Baustein für die Untersuchung pharmakokinetischer Prozesse dar. Die entwickelten CYP-TXP-Tests quantifizieren die im menschlichen Fremdstoffmetabolismus beteiligten Cytochrom P450 Enzyme spezifisch und sensitiv. Die Tests erlauben es, simultan in einem einzelnen LC-MS-Lauf mehrere Analyte zu vermessen. Die zwei entwickelten multiplexen Quantifizierungsaufbauten sind in der Lage, nach Immunopräzipitation die Quantifizierung aller 15 im Fremdstoffmetabolismus relevanten Cytochrom P450 Enzyme, sowie des ABC-Transporters MDR1 und der NADPH-Cytochrom-P450-Oxidoreduktase zu ermöglichen. Die verwendeten TXP-Antikörper wurden eingehend charakterisiert und validiert. Neben der Bestimmung der Dissoziationskonstanten und Bindekapazitäten wurde der lineare Messbereich der TXP-Tests bestimmt. Ein breiter linearer Messbereich ermöglicht es, stark variierende Konzentrationsspiegel ohne Anpassung des Probevolumens zu vermessen. Somit sind die TXP-Tests besonders für Induktionsstudien geeignet und werden gleichzeitig den in der Bevölkerung stark schwankenden Expressionsspiegeln der Cytochrom P450 Enzyme gerecht. In Induktionsexperimenten konnten hierbei in der Literatur beschriebene Induktionsprozesse bestätigt werden. In Adriamycin-resistenten Zellen wurde zudem eine gesteigerte Expression des MDR1-Transporters nachgewiesen. Die hohen Sensitivitäten der TXP-Tests erlauben es, Cytochrom P450 Enzyme aus Lebergewebe ohne vorhergehende Mikrosomenpräparation zu quantifizieren. Die Quantifizierung der Cytochrom P450-Enzyme kann hierbei sowohl aus mikrosomalen Präparationen, als auch aus Gewebe erfolgen. Kleinste Gewebe- oder Zelllysatmengen von weniger als 10 μg Gewebe reichen für eine robuste Quantifizierung aus. Die entwickelten CYP-TXP-Tests eignen sich somit für die Quantifizierung in miniaturisierten Zellkulturexperimenten im 96-Well-Format.The degradation processes of xenobiotics are primarily of interest to the pharmaceutical industry. The quantification strategy developed in this thesis completes the research of drug metabolism mostly based on mRNA expression studies and enzyme activity tests with the knowledge of the protein amount. The concentration levels of cytochrome P450 enzymes build an important component for the investigation of pharmacokinetic processes. The developed CYP-TXP-tests are able to quantify the cytochrome P450 enzymes in a specific and sensitive way. The tests permit the simultaneous quantification of several analytes in only one LC-MS run. Two quantification setups were developed which have the ability to quantify 15 cytochrome P450 enzymes as well as the abc-tansporter MDR1 and the NADPH-cytochrome-p450-oxidoreductase after immunoprecipitation. Employed TXP-antibodies were characterized and validated in-depth. In addition to dissociation constants and binding capacities the linear ranges of the TXP-tests were determined. A broad linear range affords to measure highly varying concentration levels without adapting sample volumes. Thus the TXP tests are particularly suitable to conduct induction studies and meet very fluctuating expression levels of cytochrome P450 enzymes in population. Induction experiments confirmed induction processes described in literature. Furthermore an increased expression of the transporter protein MDR1 was demonstrated in Adriamycin-resistant cells. The high sensitivities of the TXP-tests enable the quantification of cytochrome P450 enzymes in liver tissue without preparing microsomes. It is possible to quantify cytochrome P450 enzymes out of both microsomal preparation and tissue. Very small amounts of tissue or cell lysate are sufficient to quantify out of 10 µg tissue in a robust way. Therefore the developed CYP-TXP-tests are suited for the quantification in miniaturised cell culture experiments using the 96-well-format

Ambient UFP Measurements – Options & Limitations of current measurement techniques

Air pollution due to particulate matter, especially ultrafine particles, and the related negative effects (health problems, economic damage) has become one of the major problems our society is faced with today. In order to be able to investigate and to assess the real exposition of the general public in a comprehensive way, the performance of precise and accurate measurements of particulate matter is an essential part of air pollution control. For the monitoring of ultrafine and engineered nanoparticles, typically Condensation Particle Counters and Differential Electric Mobility Sprectrometers are used. Depending on the aim of research the requirements on the monitoring instruments might be significantly different. Whereas for a general approach a low time resolution and higher detection limit might be acceptable, a more detailed analysis and source appointment desire detection limits down to 1nm, 1s time resolution or differentiation between volatile and non-volatile components. This presentation will show and discuss the possibilities and limitations of currently available instruments based on the examples from airport measurements or ship emissions

Reducing infection risk and optimization of airing concepts for indoor air quality by accurate aerosol and CO2 measurement

Since the outbreak of the SARS-CoV-2 pandemic and the findings about the virus transmission route through aerosols, indoor air quality is a major topic when it comes to efforts to contain the spread of SARSCoV- 2 in the population. Most calculations of infection risk, however, still rely on CO2 as a proxy for exhaled aerosols. This assumption is no longer valid when air filtration devices are used, arising the need to include actual measured aerosol concentration into the calculation of indoor infection risk. To close this gab, a version of Wells-Riley equation, extended to include the effect of air filtration into determination of reproductive number, is introduced and applied to measurement data from indoor air quality during school lessons. The results show, that taking only CO2 into account will overestimate the real infection risk from aerosols by 20% in the cases without air filtration and by 60% in the cases with air filtration. Furthermore, measurement results varied strongly between different classrooms. This indicates that general airing recommendation, as applied during these tests, are not enough to assure a healthy environment and more individual measurements are necessary.publishedVersio

LuFo V-3 CORINNE - Schlussbericht Comfort Of Ride Improved eNgiNEering -Komfortverbesserung im niederfrequenten Bereich für Hubschrauber

Hubschrauberpiloten sind auch in aktuellen Hubschraubermustern einem hohen Vibrationsniveau ausgesetzt. Diese Vibrationen können negative Auswirkungen auf die Gesundheit und die Leistungsfähigkeit der Hubschrauberbesatzung und der Passagiere haben. Insbesondere Schwingungen im niederfrequenten Bereich standen dabei im Fokus des Verbundprojekts CORINNE. Diese Vibrationen werden u.a. durch Turbulenz angeregt und wirken verstärkt durch Flugregelungssysteme und Autopiloten auf die flugmechanischen Moden des Hubschraubers. Im DLR-Beitrag von CORINNE wurde hauptsächlich an drei Teilaspekten zur Reduzierung der niederfrequenten Vibrationen geforscht. Erstens wurde ein Turbulenzmodell für den Forschungshubschrauber ACT/FHS auf Basis von Flugversuchsdaten erstellt und validiert. Dieses sog. CETI-Modell wurde auch auf andere Hubschraubermuster skaliert. Zusätzlich ist es im ACT/FHS und AVES Simulator verfügbar, um Turbulenz zu simulieren. Zweitens wurde das Simulationsverfahren UPM in das Hubschraubersimulationsmodell von Airbus Helicopters integriert und validiert. Mit diesem Simulationsverfahren können flugmechanische Stabilitätseigenschaften wie die der Phygoide und des Dutch Rolls genauer vorhersagt und die Simulationsgüte im Manöverflug gesteigert werden. Drittens wurde ein Beobachter für die longitudinalen und lateralen Rotormastmomente des ACT/FHS auf Basis von Flugversuchsdaten entwickelt. Der Beobachter benötigt dabei lediglich Messgrößen aus dem stehenden Hubschraubersystem, welche auch auf Serienhubschraubern verfügbar sind. Durch die Integration des Beobachters in die Flugregelung soll der Komfort in turbulenter Luft gesteigert werden

A spinorial energy functional: critical points and gradient flow

On the universal bundle of unit spinors we study a natural energy functional whose critical points, if dim M \geq 3, are precisely the pairs (g, {\phi}) consisting of a Ricci-flat Riemannian metric g together with a parallel g-spinor {\phi}. We investigate the basic properties of this functional and study its negative gradient flow, the so-called spinor flow. In particular, we prove short-time existence and uniqueness for this flow.Comment: Small changes, final versio

Exhaled Aerosols in SARS-CoV-2 Polymerase Chain Reaction-Positive Children and Age-Matched-Negative Controls

BackgroundChildren and adolescents seem to be less affected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease in terms of severity, especially until the increasing spread of the omicron variant in December 2021. Anatomical structures and lower number of exhaled aerosols may in part explain this phenomenon. In a cohort of healthy and SARS-CoV-2 infected children, we compared exhaled particle counts to gain further insights about the spreading of SARS-CoV-2.Materials and MethodsIn this single-center prospective observational trial, a total of 162 children and adolescents (age 6–17 years), of whom 39 were polymerase chain reaction (PCR)-positive for SARS-CoV-2 and 123 PCR-negative, were included. The 39 PCR-positive children were compared to 39 PCR-negative age-matched controls. The data of all PCR-negative children were analyzed to determine baseline exhaled particle counts in children. In addition, medical and clinical history was obtained and spirometry was measured.ResultsBaseline exhaled particle counts were low in healthy children. Exhaled particle counts were significantly increased in SARS-CoV-2 PCR-positive children (median 355.0/L; range 81–6955/L), compared to age-matched -negative children (median 157.0/L; range 1–533/L; p < 0.001).ConclusionSARS-CoV-2 PCR-positive children exhaled significantly higher levels of aerosols than healthy children. Overall children had low levels of exhaled particle counts, possibly indicating that children are not the major driver of the SARS-CoV-2 pandemic.Trial Registration[ClinicalTrials.gov], Identifier [NCT04739020]

A heat flow for special metrics

On the space of positive 3–forms on a seven–manifold, we study the negative gradient flow of a natural functional and prove short–time existence and uniqueness

Reducing infection risk and optimization of airing concepts for indoor air quality by accurate aerosol and CO2 measurement

Since the outbreak of the SARS-CoV-2 pandemic and the findings about the virus transmission route through aerosols, indoor air quality is a major topic when it comes to efforts to contain the spread of SARSCoV- 2 in the population. Most calculations of infection risk, however, still rely on CO2 as a proxy for exhaled aerosols. This assumption is no longer valid when air filtration devices are used, arising the need to include actual measured aerosol concentration into the calculation of indoor infection risk. To close this gab, a version of Wells-Riley equation, extended to include the effect of air filtration into determination of reproductive number, is introduced and applied to measurement data from indoor air quality during school lessons. The results show, that taking only CO2 into account will overestimate the real infection risk from aerosols by 20% in the cases without air filtration and by 60% in the cases with air filtration. Furthermore, measurement results varied strongly between different classrooms. This indicates that general airing recommendation, as applied during these tests, are not enough to assure a healthy environment and more individual measurements are necessary