Publications by authors named "Rix A"

Objectives: Inflammatory bowel disease (IBD) subdivides into Crohn disease (CD) and ulcerative colitis (UC), and is characterized by unpredictable periods of inflammation and results in significant patient suffering and even death. Conventional diagnostic methods, for example, colonoscopy, computed tomography, or magnetic resonance imaging, have limitations such as invasiveness, patient discomfort, and limited sensitivity and accuracy. Therefore, we propose ultrasound molecular imaging (USMI) to detect and characterize IBD.

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Background: Severe injuries caused by accidents, like traumatic brain injury (TBI) or thoracic trauma (TT) continue to be the leading cause of death in younger people with relevant socio-economic impact. Fast and targeted diagnostics is essential for further therapy decisions and prognosis. The following study investigates NSE as a potential biomarker for lung injury after blunt TT.

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Molecular ultrasound imaging with actively targeted microbubbles (MB) proved promising in preclinical studies but its clinical translation is limited. To achieve this, it is essential that the actively targeted MB can be produced with high batch-to-batch reproducibility with a controllable and defined number of binding ligands on the surface. In this regard, poly (n-butyl cyanoacrylate) (PBCA)-based polymeric MB have been used for US molecular imaging, however, ligand coupling was mostly done via hydrolysis and carbodiimide chemistry, which is a multi-step procedure with poor reproducibility and low MB yield.

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Microbubbles (MB) are widely used as contrast agents for ultrasound (US) imaging and US-enhanced drug delivery. Polymeric MB are highly suitable for these applications because of their acoustic responsiveness, high drug loading capability, and ease of surface functionalization. While many studies have focused on using polymeric MB for diagnostic and therapeutic purposes, relatively little attention has thus far been paid to improving their inherent imaging and drug delivery features.

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Biohybrid tissue-engineered vascular grafts (TEVGs) promise long-term durability due to their ability to adapt to hosts' needs. However, the latter calls for sensitive non-invasive imaging approaches to longitudinally monitor their functionality, integrity, and positioning. Here, we present an imaging approach comprising the labeling of non-degradable and degradable TEVGs' components for their in vitro and in vivo monitoring by hybrid H/F MRI.

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Ultrasound is widely used in the diagnosis and therapy of cancer. Tumors can be treated by thermal or mechanical tissue ablation. Furthermore, tumors can be manipulated by hyperthermia, sonodynamic therapy and sonoporation, e.

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Active targeting can enhance precision and efficacy of drug delivery systems (DDS) against cancers. Riboflavin (RF) is a promising ligand for active targeting due to its biocompatibility and high riboflavin-receptor expression in cancers. In this study, RF-targeted 4-arm polyethylene glycol (PEG) stars conjugated with Paclitaxel (PTX), named PEG PTX RF, were evaluated as a targeted DDS.

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Drug delivery to central nervous pathologies is compromised by the blood-brain barrier (BBB). A clinically explored strategy to promote drug delivery across the BBB is sonopermeation, which relies on the combined use of ultrasound (US) and microbubbles (MB) to induce temporally and spatially controlled opening of the BBB. We developed an advanced in vitro BBB model to study the impact of sonopermeation on the delivery of the prototypic polymeric drug carrier pHPMA as a larger molecule and the small molecule antiviral drug ribavirin.

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Antarctic notothenioid fishes, inhabiting the oxygen-rich Southern Ocean, possess a polyglutamine and glutamic acid (poly Q/E) insertion mutation in the master transcriptional regulator of oxygen homeostasis, hypoxia- inducible factor-1α (HIF-1α). To determine if this mutation impairs the ability of HIF-1 to regulate gene expression in response to hypoxia, we exposed Notothenia coriiceps, with a poly Q/E insertion mutation in HIF-1α that is 9 amino acids long, to hypoxia (2.3 mg L O) or normoxia (10 mg L O) for 12 h.

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Despite its high potential, non-viral gene therapy of cancer remains challenging due to inefficient nucleic acid delivery. Ultrasound (US) with microbubbles (MB) can open biological barriers and thus improve DNA and mRNA passage. Polymeric MB are an interesting alternative to clinically used lipid-coated MB because of their high stability, narrow size distribution, and easy functionalization.

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Objective: Ultrasound localization microscopy (ULM) has gained increasing attention in recent years because of its ability to visualize blood vessels at super-resolution. The field of oncology, in particular, could benefit from detailed vascular characterization, for example, for diagnosis and therapy monitoring. This study was aimed at refining ULM for breast cancer patients by optimizing the measurement protocol, identifying translational challenges and combining ULM and shear wave elastography.

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Acetylsalicylic acid (ASA) is a well-established drug for heart attack and stroke prophylaxis. Furthermore, numerous studies have reported an anti-carcinogenic effect, but its exact mechanism is still unknown. Here, we applied VEGFR-2-targeted molecular ultrasound to explore a potential inhibitory effect of ASA on tumor angiogenesis in vivo.

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Objectives: Computed tomography (CT) imaging is considered relatively safe and is often used in preclinical research to study physiological processes. However, the sum of low-dose radiation, anesthesia, and animal handling might impact animal welfare and physiological parameters. This is particularly relevant for longitudinal studies with repeated CT examinations.

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Microbubbles (MB) are used as ultrasound (US) contrast agents in clinical settings because of their ability to oscillate upon exposure to acoustic pulses and generate nonlinear responses with a stable cavitation profile. Polymeric MB have recently attracted increasing attention as molecular imaging probes and drug delivery agents based on their tailorable acoustic responses, high drug loading capacity, and surface functionalization capabilities. While many of these applications require MB to be functionalized with biological ligands, the impact of bioconjugation on polymeric MB cavitation and acoustic properties remains poorly understood.

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Objective: Hip fractures are common and significantly impact mobility and physical function. Measurement of patient progress post hip fracture in the acute hospital setting is important to monitor early recovery and outcomes. The objective of this systematic review was to assess the measurement properties (reliability, validity, responsiveness), interpretability, and clinical utility of instruments used to measure mobility and physical function in patients with hip fracture in the acute hospital setting.

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Decarbonisation of Africa's informal paratransit through electrification requires adequate data captured correctly. Field workers getting on-board as passengers with tracked phones are extensively used to measure flow rates and volumes of passengers and vehicles on sections of roads in transport planning applications. Although this method is acceptable for transport planning, it is inadequate for planning for electrification.

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Introduction: Ultrasound (US) imaging enables tissue visualization in high spatial resolution with short examination times. Thus, it is often applied in preclinical research. Diagnostic US, including contrast-enhanced US (CEUS), is considered to be well-tolerated by laboratory animals although no systematic study has been performed to confirm this claim.

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The outcomes of survivors of critical illness due to coronavirus disease (COVID-19) compared with non-COVID-19 are yet to be established. We aimed to investigate new disability at 6 months in mechanically ventilated patients admitted to Australian ICUs with COVID-19 compared with non-COVID-19. We included critically ill patients with COVID-19 and non-COVID-19 from two prospective observational studies.

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Tissue-engineered vascular grafts (TEVGs) with the ability to grow and remodel open new perspectives for cardiovascular surgery. Equipping TEVGs with synthetic polymers and biological components provides a good compromise between high structural stability and biological adaptability. However, imaging approaches to control grafts' structural integrity, physiological function, and remodeling during the entire transition between late in vitro maturation and early in vivo engraftment are mandatory for clinical implementation.

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Environmental health studies are increasingly measuring multiple pollutants to characterize the joint health effects attributable to exposure mixtures. However, the underlying dose-response relationship between toxicants and health outcomes of interest may be highly nonlinear, with possible nonlinear interaction effects. Existing penalized regression methods that account for exposure interactions either cannot accommodate nonlinear interactions while maintaining strong heredity or are computationally unstable in applications with limited sample size.

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Purpose: Publication numbers reporting that ultrasound can stimulate immune reactions in tumors steadily increase. However, the presented data are partially conflicting, and mechanisms are difficult to identify from single publications. These shortcomings can be addressed by a systematic review and meta-analysis of current literature.

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Background: There are few reports of new functional impairment following critical illness from COVID-19. We aimed to describe the incidence of death or new disability, functional impairment and changes in health-related quality of life of patients after COVID-19 critical illness at 6 months.

Methods: In a nationally representative, multicenter, prospective cohort study of COVID-19 critical illness, we determined the prevalence of death or new disability at 6 months, the primary outcome.

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Preclinical and clinical data indicate that contrast-enhanced ultrasound can enhance tumor perfusion and vessel permeability, thus, improving chemotherapy accumulation and therapeutic outcome. Therefore, we investigated the effects of high mechanical index (MI) contrast-enhanced Doppler ultrasound (CDUS) on tumor perfusion in breast cancer. In this prospective study, breast cancer patients were randomly assigned to receive either 18 minutes of high MI CDUS during chemotherapy infusion (n = 6) or chemotherapy alone (n = 5).

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Background: Patients with advanced colorectal cancer (CRC) have a poor prognosis. Combinations of immunotherapies and anti-angiogenic agents are currently being evaluated in clinical trials. In this study, the multikinase inhibitor regorafenib (REG) was combined with an anti-programmed cell death protein 1 (aPD1) antibody in syngeneic murine microsatellite-stable (MSS) CT26 and hypermutated MC38 colon cancer models to gain mechanistic insights into potential drug synergism.

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Microbubbles (MB) are used as ultrasound (US) contrast agents and can be efficiently targeted against markers of angiogenesis and inflammation. Due to their gas core, MB locally alter susceptibilities in magnetic resonance imaging (MRI), but unfortunately, the resulting contrast is low and not sufficient to generate powerful molecular MRI probes. Therefore, we investigated whether a potent molecular MR agent can be generated by encapsulating superparamagnetic iron oxide nanoparticles (SPION) in the polymeric shell of poly (n-butylcyanoacrylate) (PBCA) MB and targeted them against αβ integrins on the angiogenic vasculature of 4T1 murine breast carcinomas.

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