https://ediss.sub.uni-hamburg.de:443/handle/ediss/2 2026-09-12T00:59:15Z https://ediss.sub.uni-hamburg.de:443/handle/ediss/12581 Title: Invasive Ventilation and Mortality in Critically Ill Nonagenarians: A Retrospective Cohort Study Authors: Haar, Markus Abstract: In dieser retrospektiven Kohorte von 1.422 ICU-Patient:innen ≥90 Jahre war invasive Beatmung (IV) häufig und mit deutlich höherer ICU- und Krankenhausmortalität assoziiert. Die Gesamtsterblichkeit war hoch (kumulative Sterblichkeitswahrscheinlichkeit 50,4% nach 6 Monaten und 59,4% nach 12 Monaten) und lag bei Patient:innen mit IV höher als ohne IV (12 Monate: 73,2% vs. 53,4%). Entscheidend war jedoch die Dauer der IV: Eine Beatmung >72 Stunden identifizierte konsistent eine Hochrisikogruppe mit sehr ungünstiger Prognose. Zusammen mit erhöhtem Laktat, hohen SOFA-Scores und hoher Komorbidität ergeben sich pragmatische Marker, die früh im Verlauf verfügbar sind. Klinisch unterstützen die Daten, IV – insbesondere fehlende Entwöhnung innerhalb von 72 Stunden – als Anlass für frühe, strukturierte und patientenzentrierte Therapiezielgespräche und ggf. zeitlich begrenzte ICU-Therapieversuche zu nutzen. Aufgrund des Beobachtungsdesigns und fehlender geriatrischer Kernvariablen sind die Befunde als Prognosesignale zu verstehen und belegen keine Kausalität der IV für Mortalität.; In this retrospective cohort of 1,422 ICU patients aged ≥90 years, invasive ventilation (IV) was common and associated with substantially higher ICU and hospi-tal mortality. Overall mortality was high (cumulative mortality risk 50.4% at 6 months and 59.4% at 12 months) and was higher in patients who received IV than in those never ventilated (12 months: 73.2% vs 53.4%). The key discriminator, however, was duration: IV persisting beyond 72 hours consistently identified a subgroup with very poor prognosis. Together with elevated lactate, high SOFA scores, and greater comorbidity burden, these findings provide pragmatic early markers that can support clinical decision-making. Clinically, the results support using IV – particularly failure to achieve liberation within 72 hours – as a trigger for early, structured, patient-centred goals-of-care discussions and consideration of time-limited ICU trials. Given the observational design and missing geriatric variables, these associations should be interpreted as prognostic signals rather than evidence that IV itself causes excess mortality. 2026-09-11T12:20:09Z https://ediss.sub.uni-hamburg.de:443/handle/ediss/12588 Title: Reduktion der Strahlendosis im Verlauf bei einem neuen interventionellen Verfahren am Beispiel der Prostataarterienembolisation (PAE) Authors: Wentz, Rabea Maria 2026-09-11T11:40:42Z https://ediss.sub.uni-hamburg.de:443/handle/ediss/12574 Title: Investigation on insect-specific viruses - West Nile virus interactions: focus on European Culex pipiens mosquitoes Authors: Gothe Esteves Viegas, Sarah Abstract: Arboviruses such as West Nile virus (WNV) and Usutu virus (USUV) represent an increasing public health concern in Europe, where mosquitoes of the Culex pipiens complex and Culex torrentium serve as principal vectors. Despite their epidemiological relevance, the molecular determinants underlying arbovirus infection and vector competence in Culex mosquitoes remain insufficiently understood. In parallel, insect-specific viruses (ISVs), which are restricted to insect hosts, have emerged as important components of the mosquito virome with the potential to modulate arbovirus replication and transmission. Using a combination of in vitro infection assays, small RNA sequencing, virome analysis, and in vivo mosquito infection experiments, this study evaluated viral replication kinetics, antiviral RNA interference (RNAi) responses, and potential interference effects between ISVs and medically relevant arboviruses. Two newly established Cx. pipiens-derived cell lines (CPE/LULS50 and CPL/LULS56) were characterized using representative viruses from the families Flaviviridae, Togaviridae, and Peribunyaviridae. Both cell lines supported replication of a broad range of arboviruses and ISVs and exhibited robust virus-derived siRNA responses, confirming functional RNAi activity. In contrast to many established mosquito cell lines, no evidence of persistent ISV infections was detected, highlighting their suitability as controlled experimental systems. Co-infection experiments in cell culture using the insect-specific viruses Eilat virus (EILV) and Niénokoué virus (NIEV) revealed no consistent modulation of arbovirus replication, including WNV and USUV, under both acute and persistent infection conditions. Similarly, in vivo experiments demonstrated that prior infection with the insect-specific Agua Salud alphavirus (ASALV) did not significantly alter WNV infection or transmission dynamics in Cx. pipiens biotype pipiens mosquitoes. Infection studies further indicated that ISV susceptibility is highly dependent on infection route, with efficient infection following intrathoracic injection but limited infection via oral exposure, suggesting midgut-associated barriers. Collectively, these findings demonstrate that ISV-arbovirus interactions are highly complex and context-dependent, influenced by factors such as virus strain, infection timing, and host background. While ISVs remain promising candidates for innovative vector control strategies, the lack of consistent interference observed in this study highlights the need for comprehensive evaluation across diverse experimental and ecological settings. Furthermore, this work characterized Cx. pipiens sensu stricto cell lines as valuable tools for advancing research on arbovirus-vector interactions in temperate mosquito species. 2026-09-11T10:51:57Z https://ediss.sub.uni-hamburg.de:443/handle/ediss/12594 Title: From Infection to Transmission: Determinants of Arbovirus Vector Competence in Mosquitoes Authors: Höller, Patrick Abstract: Arthropod-borne viruses (arboviruses), specifically those transmitted by mosquitoes, are an increasing public health threat. This trend is amplified by globalization and climate change, which enable their spread into new regions. However, the transmission dynamics and vector competence of many arboviruses remain poorly understood, with more than 90% of potential virus-mosquito combinations remaining untested. This lack of knowledge limits accurate risk assessment and preparedness. Understanding how key determinants shape the transmission of arboviruses by mosquitoes is therefore of increasing importance. In this dissertation, the transmission dynamics of arboviruses endemic to (West Nile virus, Tahyna virus) and exotic to Europe (Snowshoe hare virus, Oropouche virus, Barmah Forest virus) were assessed, including a comparison of the two major West Nile virus lineages. Across the 29 virus-mosquito combinations tested, infection was observed in 97% of combinations, whereas transmission occurred in only 41%, demonstrating that infection does not necessarily lead to transmission. Vector competence varied substantially across mosquito taxa, with Aedes albopictus exhibiting the broadest transmission profile, and differed between viruses and viral lineages. All three exotic viruses were able to be transmitted by mosquitoes from Europe, highlighting the potential threat of those viruses. Effects of temperature on vector competence were heterogeneous and dependent on the specific virus-mosquito combinations. The minimum infectious dose was lower for West Nile virus lineage 2, compared with lineage 1. Overall, this dissertation demonstrates that vector competence is highly context-dependent and shaped by interactions between mosquito species, virus, temperature, and viral dose. These findings enable a more realistic assessment of arbovirus risk and highlight the need for context-specific evaluations of vector competence, as results cannot be generalized even across closely related mosquitoes or viruses. 2026-09-11T10:18:43Z