Publications by authors named "Rjp Musters"

Purpose: Intra-arterial administration of microbubbles (MBs) through an ultrasound (US) catheter increases the local concentration of MBs into the thrombus and may further enhance outcomes of contrast-enhanced sonothrombolysis (CEST). The objective of this study was to evaluate the feasibility and lytic efficacy of intra-arterial infusion of MBs during US-enhanced thrombolysis in both in vitro and in vivo peripheral arterial occluded models.

Materials And Methods: SonoVue and Luminity MBs were infused at a flow rate of 20 mL/h through either the drug delivery lumen of the US catheter (DDC, n=20) or through the tube lumen of the vascular phantom (systematic infusion, n=20) during thrombolysis with a low-dose urokinase (UK) protocol (50 000 IU/h) with(out) US application to assess MB survivability and size by pre-treatment and post-treatment measurements.

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Immunoglobulin A (IgA) is generally considered as a non-inflammatory regulator of mucosal immunity, and its importance in diversifying the gut microbiota is increasingly appreciated. IgA autoantibodies have been found in several autoimmune or chronic inflammatory diseases, but their role in pathophysiology is ill-understood. IgA can interact with the Fc receptor FcαRI on immune cells.

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Aging-associated muscle wasting and impaired regeneration are caused by deficiencies in muscle stem cell (MuSC) number and function. We postulated that aged MuSCs are intrinsically impaired in their responsiveness to omnipresent mechanical cues through alterations in MuSC morphology, mechanical properties, and number of integrins, culminating in impaired proliferative capacity. Here we show that aged MuSCs exhibited significantly lower growth rate and reduced integrin-α7 expression as well as lower number of phospho-paxillin clusters than young MuSCs.

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Catheter-directed thrombolysis (CDT) for acute peripheral arterial occlusion is time consuming and carries a risk of major hemorrhage. Contrast-enhanced sonothrombolysis (CEST) might enhance outcomes compared with standard CDT. In the study described here, we systematically reviewed all in vivo studies on contrast-enhanced sonothrombolysis in a setting of arterial thrombosis.

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Synucleinopathies such as Parkinson's disease (PD) are hallmarked by α-synuclein (α-syn) pathology and neuroinflammation. This neuroinflammation involves activated microglia with increased secretion of interleukin-1β (IL-1β). The main driver of IL-1β secretion from microglia is the NLRP3 inflammasome.

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In non-small cell lung cancer, sensitizing mutations in epidermal growth factor receptor (EGFR) or cMET amplification serve as good biomarkers for targeted therapies against EGFR or cMET, respectively. Here we aimed to determine how this different genetic background would affect the interaction between the EGFR-inhibitor erlotinib and the cMET-inhibitor crizotinib. To unravel the mechanism of synergy we investigated the effect of the drugs on various parameters, including cell cycle arrest, migration, protein phosphorylation, kinase activity, the expression of drug efflux pumps, intracellular drug concentrations, and live-cell microscopy.

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Objectives: Juxtarenal aortic surgery induces renal ischaemia reperfusion, which contributes to systemic inflammatory tissue injury and remote organ damage. Renal cooling during suprarenal cross clamping has been shown to reduce renal damage. It is hypothesised that renal cooling during suprarenal cross clamping also has systemic effects and could decrease damage to other organs, like the sigmoid colon.

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The positive findings of the EMPA-REG OUTCOME trial (Randomized, Placebo-Controlled Cardiovascular Outcome Trial of Empagliflozin) on heart failure (HF) outcome in patients with type 2 diabetes mellitus suggest a direct effect of empagliflozin on the heart. These patients frequently have HF with preserved ejection fraction (HFpEF), in which a metabolic risk-related pro-inflammatory state induces cardiac microvascular endothelial cell (CMEC) dysfunction with subsequent cardiomyocyte (CM) contractility impairment. This study showed that CMECs confer a direct positive effect on contraction and relaxation of CMs, an effect that requires nitric oxide, is diminished after CMEC stimulation with tumor necrosis factor-α, and is restored by empagliflozin.

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Herpesviruses can rewire cellular signaling in host cells by expressing viral G protein-coupled receptors (GPCRs). These viral receptors exhibit homology to human chemokine receptors, but some display constitutive activity and promiscuous G protein coupling. Human cytomegalovirus (HCMV) has been detected in multiple cancers, including glioblastoma, and its genome encodes four GPCRs.

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Granulovacuolar degeneration bodies (GVBs) are membrane-bound vacuolar structures harboring a dense core that accumulate in the brains of patients with neurodegenerative disorders, including Alzheimer's disease and other tauopathies. Insight into the origin of GVBs and their connection to tau pathology has been limited by the lack of suitable experimental models for GVB formation. Here, we used confocal, automated, super-resolution and electron microscopy to demonstrate that the seeding of tau pathology triggers the formation of GVBs in different mouse models in vivo and in primary mouse neurons in vitro.

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Purpose: We previously found that homocysteine (Hcy)-induced apoptosis in endothelial cells coincided with increased NADPH oxidase (NOX) activity. In addition, in ischemic endothelial cells present in the heart, we showed that loss of serine protease dipeptidyl peptidase IV (DPP4) expression was correlated with induction of tissue factor (TF) expression. Since Hcy can initiate thrombosis through the induction of TF expression, in this study, we evaluated whether the inverse relation of TF and DPP4 is also Hcy-dependent and whether NOX-mediated reactive oxygen species (ROS) is playing a role herein.

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Background: In abdominal aortic aneurysm (AAA), pathophysiology deterioration of the medial aortic layer plays a critical role. Key players in vessel wall degeneration are reactive oxygen species (ROS), smooth muscle cell apoptosis, and extracellular matrix degeneration by matrix metalloproteinase-9 (MMP-9). Lipocalin-2, also neutrophil gelatinase-associated lipocalin (NGAL), is suggested to be involved in these degenerative processes in other cardiovascular diseases.

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Article Synopsis
  • The study explores a new treatment using a modified antibody fragment (F8) to deliver interleukin 10 (IL10) specifically to inflamed joints in rheumatoid arthritis (RA) patients.
  • It was found that F8-IL10 rapidly clears from the bloodstream and exhibits significant targeting to arthritic joints, with notable uptake in PET-CT imaging.
  • Additionally, the biodistribution studies in arthritic animals revealed a dramatic increase in radioactivity in joints, liver, and spleen, suggesting that monitoring F8-IL10 could help visualize inflammation and improve therapeutic targeting in RA.
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The indoleamine 2,3-dioxygenase (IDO) enzyme can act as an immunoregulator by inhibiting T cell function the degradation of the essential amino acid tryptophan (trp) into kynurenine (kyn) and its derivates. The kyn/trp ratio in serum is a prognostic factor for cervical cancer patients; however, information about the relationship between serum levels and IDO expression in the tumor is lacking. IDO expression was studied in 71 primary and 14 paired metastatic cervical cancer samples by various immunohistochemical (IHC) techniques, including 7-color fluorescent multiparameter IHC, and the link between the concentration of IDO metabolites in serum, clinicopathological characteristics, and the presence of (proliferating) T cells (CD8, Ki67, and FoxP3) was examined.

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Reactive oxygen species (ROS) control forkhead box O (FOXO) transcription factor activity by influencing their nuclear translocation. However, knowledge of the ROS cellular source(s) involved herein remains scarce. Recently, we have shown p47-dependent activation of ROS-producing NADPH oxidase (NOX) at the nuclear pore in H9c2 rat cardiomyoblasts in response to ischemia.

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Alkaline phosphatase (AP) is a gate-keeper of innate immune system responses by detoxifying inflammation triggering moieties released from endogenous and external sources. We examined whether AP's broad mechanism of action constitutes a safe therapeutic, either as single agent or combined with methotrexate (MTX), for chronic inflammatory disorders, for example, rheumatoid arthritis (RA). A rat model for RA was used with repeated intra-articular methylated bovine serum albumin (mBSA) injections in 1 knee ("arthritic" knee), with the contralateral knee serving as internal control.

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The pathophysiology of aortic aneurysms (AA) is far from being understood. One reason for this lack of understanding is basic research being constrained to fixated cells or isolated cell cultures, by which cell-to-cell and cell-to-matrix communications are missed. We present a new, in vitro method for extended preservation of aortic wall sections to study pathophysiological processes.

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Rationale: Diaphragm weakness in critically ill patients prolongs ventilator dependency and duration of hospital stay and increases mortality and healthcare costs. The mechanisms underlying diaphragm weakness include cross-sectional fiber atrophy and contractile protein dysfunction, but whether additional mechanisms are at play is unknown.

Objectives: To test the hypothesis that mechanical ventilation with positive end-expiratory pressure (PEEP) induces longitudinal atrophy by displacing the diaphragm in the caudal direction and reducing the length of fibers.

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Background: Marfan syndrome (MFS), a congenital connective tissue disorder leading to aortic aneurysm development, is caused by fibrillin-1 (FBN1) gene mutations. Transforming growth factor beta (TGF-β) might play a role in the pathogenesis. It is still a matter of discussion if and how TGF-β up-regulates the intracellular downstream pathway, although TGF-β receptor 3 (TGFBR3 or Betaglycan) is thought to be involved.

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Article Synopsis
  • - Daratumumab significantly lowers CD38 expression on multiple myeloma cells within hours, and this effect happens regardless of the treatment's depth or duration as seen in the GEN501 and GEN503 studies.
  • - The reduction in CD38 levels was also noted in nontumor immune cells like natural killer cells and T cells, suggesting a broader impact of the treatment beyond just tumor cells.
  • - Mechanistically, the decrease in CD38 expression is linked to a process called trogocytosis, where daratumumab-CD38 complexes are transferred to other immune cells, which may contribute to the drug's effectiveness in treating multiple myeloma.
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Objectives: Extensive reactive oxygen and nitrogen species (also reactive species) production is a mechanism involved in abdominal aortic aneurysm (AAA) development. White blood cells (WBCs) are a known source of reactive species. Their production may be decreased by statins, thereby reducing the AAA growth rate.

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Background: Three-dimensional visualization of the brain vasculature and its interactions with surrounding cells may shed light on diseases where aberrant microvascular organization is involved, including glioblastoma (GBM). Intravital confocal imaging allows 3D visualization of microvascular structures and migration of cells in the brain of mice, however, with limited imaging depth. To enable comprehensive analysis of GBM and the brain microenvironment, in-depth 3D imaging methods are needed.

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Background: Standard therapy in acute peripheral arterial occlusion consists of intra-arterial catheter-guided thrombolysis. As microbubbles may be used as a carrier for fibrinolytic agents and targeted to adhere to the thrombus, we can theoretically deliver the thrombolytic medication locally following simple intravenous injection. In this intervention-controlled feasibility study, we compared intravenously administered targeted microbubbles incorporating urokinase and locally applied ultrasound, with intravenous urokinase and ultrasound alone.

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Mutations in genes encoding proteins of the smooth muscle cell (SMC) contractile apparatus contribute to familial aortic aneurysms. To investigate the pathogenicity of these mutations, SMC are required. We demonstrate a novel method to generate SMC-like cells from human dermal fibroblasts by transdifferentiation to study the effect of variants in genes encoding proteins of the SMC contractile apparatus (ACTA2 and MYH11) in patients with aortic aneurysms.

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Key Points: Calcium ions regulate mitochondrial ATP production and contractile activity and thus play a pivotal role in matching energy supply and demand in cardiac muscle. The magnitude and kinetics of the changes in free mitochondrial calcium concentration in cardiac myocytes are largely unknown. Rapid stimulation frequency-dependent increases but relatively slow decreases in free mitochondrial calcium concentration were observed in rat cardiac myocytes.

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