A volume-averaged model for acoustic streaming induced by focused ultrasound in soft porous media.

Equations describing acoustic streaming in soft, porous media driven by focused ultrasound are derived based on the assumption that acoustic waves pass through the porous material as if it were homogeneous. From these equations, a model that predicts the time-averaged flow on the macroscopic scale, as well as the advective transport of the trace components, is created. The model is used to perform simulations for different shapes of the focused ultrasound beam. For a given shape, and using the paraxial approximation for the ultrasound, the acoustic streaming is found to be linearly proportional to the applied ultrasound intensity, to the permeability of the porous material and to the attenuation coefficient, and inversely proportional to the liquid viscosity. Results from simulations are compared to a simplified expression stating that the dimensionless volumetric liquid flux is equal to the dimensionless acoustic radiation force. This approximation for the acoustic streaming is found to be reasonable near the beam axis for focused ultrasound beam shapes that are long in the axial direction, compared to their width. Finally, a comparison is made between the model and experimental results on acoustic streaming in a gel, and good agreement is found.

Estimation of fat content in soft tissues using dual frequency ultrasound-A phantom study.

This paper presents an initial investigation into the use of dual frequency pulse-echo ultrasound, second order ultrasound field (SURF) imaging, to measure the fat content of soft tissues. The SURF imaging method was used to measure the non-linear bulk elasticity (NBE) of several fatty phantoms that were created by mixing different mass fractions of soybean oil uniformly into agar phantoms. The median of the measured NBE within the estimation region was found to increase linearly with fat mass fraction (R2 = 0.99), from 1.7 GPa-1 at 9.6% fat to 2.52 GPa-1 at 63.6% fat, thus, showing promise as a sensitive parameter for fat content measurement. Comparisons to mixture laws in earlier literature are made, and the most important error sources that need to be considered for the in vivo applications of the method are discussed.

Company-sponsored egg freezing: an offer you can't refuse?

The aim of this article is to argue that one of the central arguments against company-sponsored non-medical egg freezing, namely that this practice is contrary to the reproductive autonomy of women, can be difficult to sustain under certain conditions. More specifically, we argue that company-sponsored egg freezing is not necessarily in conflict with the most common requirements for autonomous choice. That is, there is no reason to assume that employees cannot be adequately informed beforehand about what is scientifically known about the practice, and/or that they lack the required capacity to understand and process this information. Although they may feel a certain pressure to comply with the wishes of their employer, this concern can plausibly be alleviated through privacy regulations. In any event, such pressure is arguably not stronger than or relevantly different from other types of pressure on the labour market that most people readily accept as being ethically acceptable. Finally, we argue that company-sponsored non-medical egg freezing may mitigate certain types of oppressive socialization, although it may well perpetuate others, and should in any case arguably be dealt with through guidelines and counselling, which would ensure that women make autonomous choices when companies offer egg freezing.

Cardiac Alarmins as Residual Risk Markers of Atherosclerosis under Hypolipidemic Therapy.

Increased levels of low-density lipoproteins are the main risk factor in the initiation and progression of atherosclerosis. Although statin treatment can effectively lower these levels, there is still a residual risk of cardiovascular events. We hypothesize that a specific panel of stress-sensing molecules (alarmins) could indicate the persistence of silent atherosclerosis residual risk. New Zealand White rabbits were divided into: control group (C), a group that received a high-fat diet for twelve weeks (Au), and a treated hyperlipidemic group with a lipid diet for eight weeks followed by a standard diet and hypolipidemic treatment (atorvastatin and PCSK9 siRNA-inhibitor) for four weeks (Asi). Mass spectrometry experiments of left ventricle lysates were complemented by immunologic and genomic studies to corroborate the data. The hyperlipidemic diet determined a general alarmin up-regulation tendency over the C group. A significant spectral abundance increase was measured for specific heat shock proteins, S100 family members, HMGB1, and Annexin A1. The hypolipidemic treatment demonstrated a reversed regulation trend with non-significant spectral alteration over the C group for some of the identified alarmins. Our study highlights the discriminating potential of alarmins in hyperlipidemia or following hypolipidemic treatment. Data are available via ProteomeXchange with identifier PXD035692.

Density calibrated cone beam CT as a tool for adaptive radiotherapy.

BACKGROUND: Visual inspections of anatomical changes observed on daily cone-beam CT (CBCT) images are often used as triggers for radiotherapy plan adaptation to avoid unacceptable dose levels to the target or OARs. Direct CBCT dose calculations would improve the ability to adapt only those plans where dosimetric changes are observed. This study investigates the accuracy of dose calculations on CBCTs. MATERIALS AND METHODS: Calibration curves were obtained for CBCT imagers at nine identical accelerators. CBCT scans of a phantom with different density inserts were recorded for two scan modes (Head-Neck and Pelvis) and mean calibration curves were calculated. Subsequently, CBCT scans of the phantom with six different density inserts were recorded, the dose distributions on the CBCTs were calculated and compared to dose on the planning CT (pCT). The uncertainty was quantified by the dosimetric difference between the pCT and the CBCT. The two mean calibration curves were used to calculate the daily delivered CBCT dose for ten Head-Neck-, eleven Lung-, and ten pelvic patients. Additional patient calculations were performed using low-HU empirically corrected calibration curves. Patient doses were compared on target coverage and mean dose, and D1cc for OARs. RESULTS: The dose differences between pCT and CBCT for phantom data were small for all DVH parameters, with mean deviations below ±0.6% for both CBCT modes. For patient data, it was found that low-HU corrected calibration curves performed the best. The mean deviations for the mean dose and coverage of the target were 0.2%±0.7% and 0.1%±0.6%, across all patient groups. CONCLUSION: Dose calculation on CBCT images results in target coverage and mean dose with an accuracy of the order of 1%, which makes this acceptable for clinical use. The CBCT mode specific calibration curves can be used at all identical imaging devices and for all patient groups.

Targeted molecular genetic testing in young sudden cardiac death victims from Western Denmark.

Sudden unexpected death in the young continues to be an important unsolved challenge. A significant proportion of the deaths are suspected to be caused by inherited cardiac diseases and are referred to as sudden cardiac deaths (SCD). We performed targeted molecular testing of 70 deceased individuals under 40 years of age that after forensic autopsy were suspected to have died of SCD. The individuals were previously genetically investigated using smaller numbers of genes associated with specific cardiac diseases. In our previous studies, seven (10%) individuals had pathogenic or likely pathogenic variants according to the 2015 ACMG guidelines. In order to investigate the value of expanding the panel to 100 genes associated with cardiac diseases, we histopathologically re-examined the 70 suspected SCD cases and grouped them according to phenotypes into suspected cardiomyopathy (the cardiomyopathy group), left ventricular hypertrophy (the hypertrophy group) and structural normal hearts (the SUD group). DNA was captured with the Haloplex target enrichment system and sequenced using an Illumina MiSeq. We found that 11 (16%) individuals harboured pathogenic or likely pathogenic variants. In the cardiomyopathy, hypertrophy and SUD groups, 22%, 6% and 17% of the individuals, respectively, harboured pathogenic or likely pathogenic variants. Our findings show that testing of a broad panel of genes associated with cardiac diseases identify potential pathogenic variants of cardiac diseases in a significant proportion of SCD cases, and this may have important implications in family screening to prevent future deaths.

Northern bottlenose whales in a pristine environment respond strongly to close and distant navy sonar signals.

Impact assessments for sonar operations typically use received sound levels to predict behavioural disturbance in marine mammals. However, there are indications that cetaceans may learn to associate exposures from distant sound sources with lower perceived risk. To investigate the roles of source distance and received level in an area without frequent sonar activity, we conducted multi-scale controlled exposure experiments ( n = 3) with 12 northern bottlenose whales near Jan Mayen, Norway. Animals were tagged with high-resolution archival tags ( n = 1 per experiment) or medium-resolution satellite tags ( n = 9 in total) and subsequently exposed to sonar. We also deployed bottom-moored recorders to acoustically monitor for whales in the exposed area. Tagged whales initiated avoidance of the sound source over a wide range of distances (0.8-28 km), with responses characteristic of beaked whales. Both onset and intensity of response were better predicted by received sound pressure level (SPL) than by source distance. Avoidance threshold SPLs estimated for each whale ranged from 117-126 dB re 1 µPa, comparable to those of other tagged beaked whales. In this pristine underwater acoustic environment, we found no indication that the source distances tested in our experiments modulated the behavioural effects of sonar, as has been suggested for locations where whales are frequently exposed to sonar.

A comparison of genetic findings in sudden cardiac death victims and cardiac patients: the importance of phenotypic classification.

Sudden cardiac death (SCD) is responsible for a large proportion of non-traumatic, sudden and unexpected deaths in young individuals. Sudden cardiac death is a known manifestation of several inherited cardiac diseases. In post-mortem examinations, about two-thirds of the SCD cases show structural abnormalities at autopsy. The remaining cases stay unexplained after thorough investigations and are referred to as sudden unexplained deaths. A routine forensic investigation of the SCD victims in combination with genetic testing makes it possible to establish a likely diagnosis in some of the deaths previously characterized as unexplained. Additionally, a genetic diagnose in a SCD victim with a structural disease may not only add to the differential diagnosis, but also be of importance for pre-symptomatic family screening. In the case of SCD, the optimal establishment of the cause of death and management of the family call for standardized post-mortem procedures, genetic screening, and family screening. Studies of genetic testing in patients with primary arrhythmia disorders or cardiomyopathies and of victims of SCD presumed to be due to primary arrhythmia disorders or cardiomyopathies, were systematically identified and reviewed. The frequencies of disease-causing mutation were on average between 16 and 48% in the cardiac patient studies, compared with ∼10% in the post-mortem studies. The frequency of pathogenic mutations in heart genes in cardiac patients is up to four-fold higher than that in SCD victims in a forensic setting. Still, genetic investigation of SCD victims is important for the diagnosis and the possible investigation of relatives at risk.

Respiratory gating based on internal electromagnetic motion monitoring during stereotactic liver radiation therapy: First results.

BACKGROUND: Intrafraction motion may compromise the target dose in stereotactic body radiation therapy (SBRT) of tumors in the liver. Respiratory gating can improve the treatment delivery, but gating based on an external surrogate signal may be inaccurate. This is the first paper reporting on respiratory gating based on internal electromagnetic monitoring during liver SBRT. MATERIAL AND METHODS: Two patients with solitary liver metastases were treated with respiratory-gated SBRT guided by three implanted electromagnetic transponders. The treatment was delivered in end-exhale with beam-on when the centroid of the three transponders deviated less than 3 mm [left-right (LR) and anterior-posterior (AP) directions] and 4mm [cranio-caudal (CC)] from the planned position. For each treatment fraction, log files were used to determine the transponder motion during beam-on in the actual gated treatments and in simulated treatments without gating. The motion was used to reconstruct the dose to the clinical target volume (CTV) with and without gating. The reduction in D95 (minimum dose to 95% of the CTV) relative to the plan was calculated for both treatment courses. RESULTS: With gating the maximum course mean (standard deviation) geometrical error in any direction was 1.2 mm (1.8 mm). Without gating the course mean error would mainly increase for Patient 1 [to -2.8 mm (1.6 mm) (LR), 7.1 mm (5.8 mm) (CC), -2.6 mm (2.8mm) (AP)] due to a large systematic cranial baseline drift at each fraction. The errors without gating increased only slightly for Patient 2. The reduction in CTV D95 was 0.5% (gating) and 12.1% (non-gating) for Patient 1 and 0.3% (gating) and 1.7% (non-gating) for Patient 2. The mean duty cycle was 55%. CONCLUSION: Respiratory gating based on internal electromagnetic motion monitoring was performed for two liver SBRT patients. The gating added robustness to the dose delivery and ensured a high CTV dose even in the presence of large intrafraction motion.

Pulse-Echo Ultrasound for Quantitative Measurements of Two Uncorrelated Elastic Parameters.

OBJECTIVE: This paper describes the relationship between elastic tissue properties and strain and presents an initial investigation of pulse-echo ultrasound to measure two uncorrelated elastic parameters in tissue-mimicking phantoms. The two elastic parameters are the shear modulus, related to deformation of shape, and what we in the paper define as the nonlinear compressibility, related to deformation of volume. METHODS: We prepared tissue-mimicking phantoms containing lesions of variable shear modulus and variable nonlinear compressibility. An in-house framework for shear wave imaging was developed using ultrasound radiation force at 4.5 MHz to induce shear waves and plane wave imaging with pulses in a frequency band centered around 12.5 MHz to track the shear waves. For measurements of nonlinear compressibility, co-propagating dual-frequency pulse complexes at 0.7 MHz and 14 MHz were applied. Algorithms were implemented on a Verasonics Vantage ultrasound scanner and a custom-made multi-frequency ultrasound transducer was used. Mechanical indentation measurements were performed to validate ultrasound measurements of the shear modulus. For the nonlinear compressibility, ultrasound measurements were compared to results derived from the literature. RESULTS: We found good agreement in elasticity results from ultrasound measurements and mechanical indentation as well as when comparing with results derived from the literature. CONCLUSION: Results of the current investigation were promising. We plan patient studies involving thyroid lesions and liver steatosis to explore whether measurements of elastic parameters related both to shape deformation and volume deformation are useful in clinical practice.

Accuracy of four models and update strategies to estimate liver tumor motion from external respiratory motion.

Background: This study investigates different strategies for estimating internal liver tumor motion during radiotherapy based on continuous monitoring of external respiratory motion combined with sparse internal imaging. Methods: Fifteen patients underwent three-fraction stereotactic liver radiotherapy. The 3D internal tumor motion (INT) was monitored by electromagnetic transponders while a camera monitored the external marker block motion (EXT). The ability of four external-internal correlation models (ECM) to estimate INT as function of EXT was investigated: a simple linear model (ECM1), an augmented linear model (ECM2), an augmented quadratic model (ECM3), and an extended quadratic model (ECM4). Each ECM was constructed by fitting INT and EXT during the first 60s of each fraction. The fit accuracy was calculated as the root-mean-square error (RMSE) between ECM-estimated and actual tumor motion. Next, the RMSE of the ECM-estimated tumor motion throughout the fractions was calculated for four simulated ECM update strategies: (A) no update, 0.33Hz internal sampling with continuous update of either (B) all ECM parameters based on the last 2 minutes samples or (C) only the baseline term based on the last 5 samples, (D) full ECM update every minute using 20s continuous internal sampling. Results: The augmented quadratic ECM3 had best fit accuracy with mean (± SD)) RMSEs of 0.32 ± 0.11mm (left-right, LR), 0.79 ± 0.30mm (cranio-caudal, CC) and 0.56 ± 0.31mm (anterior-posterior, AP). However, the simpler augmented linear ECM2 combined with frequent baseline updates (update strategy C) gave best motion estimations with mean RMSEs of 0.41 ± 0.14mm (LR), 1.02 ± 0.33mm (CC) and 0.78 ± 0.48mm (AP). This was significantly better than all other ECM-update strategy combinations for CC motion (Wilcoxon signed rank p<0.05). Conclusion: The augmented linear ECM2 combined with frequent baseline updates provided the best compromise between fit accuracy and robustness towards irregular motion. It allows accurate internal motion monitoring by combining external motioning with sparse 0.33Hz kV imaging, which is available at conventional linacs.

An array of Zymoseptoria tritici effectors suppress plant immune responses.

Zymoseptoria tritici is the most economically significant fungal pathogen of wheat in Europe. However, despite the importance of this pathogen, the molecular interactions between pathogen and host during infection are not well understood. Herein, we describe the use of two libraries of cloned Z. tritici effectors that were screened to identify effector candidates with putative pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI)-suppressing activity. The effectors from each library were transiently expressed in Nicotiana benthamiana, and expressing leaves were treated with bacterial or fungal PAMPs to assess the effectors' ability to suppress reactive oxygen species (ROS) production. From these screens, numerous effectors were identified with PTI-suppressing activity. In addition, some effectors were able to suppress cell death responses induced by other Z. tritici secreted proteins. We used structural prediction tools to predict the putative structures of all of the Z. tritici effectors and used these predictions to examine whether there was enrichment of specific structural signatures among the PTI-suppressing effectors. From among the libraries, multiple members of the killer protein-like 4 (KP4) and killer protein-like 6 (KP6) effector families were identified as PTI suppressors. This observation is intriguing, as these protein families were previously associated with antimicrobial activity rather than virulence or host manipulation. This data provides mechanistic insight into immune suppression by Z. tritici during infection and suggests that, similar to biotrophic pathogens, this fungus relies on a battery of secreted effectors to suppress host immunity during early phases of colonization.

Methods for reverberation suppression utilizing dual frequency band imaging.

Reverberations impair the contrast resolution of diagnostic ultrasound images. Tissue harmonic imaging is a common method to reduce these artifacts, but does not remove all reverberations. Dual frequency band imaging (DBI), utilizing a low frequency pulse which manipulates propagation of the high frequency imaging pulse, has been proposed earlier for reverberation suppression. This article adds two different methods for reverberation suppression with DBI: the delay corrected subtraction (DCS) and the first order content weighting (FOCW) method. Both methods utilize the propagation delay of the imaging pulse of two transmissions with alternating manipulation pressure to extract information about its depth of first scattering. FOCW further utilizes this information to estimate the content of first order scattering in the received signal. Initial evaluation is presented where both methods are applied to simulated and in vivo data. Both methods yield visual and measurable substantial improvement in image contrast. Comparing DCS with FOCW, DCS produces sharper images and retains more details while FOCW achieves best suppression levels and, thus, highest image contrast. The measured improvement in contrast ranges from 8 to 27 dB for DCS and from 4 dB up to the dynamic range for FOCW.

Treatment of Liver Metastases With Focused Ultrasound and Microbubbles in Patients With Colorectal Cancer Receiving Chemotherapy.

OBJECTIVE: Pre-clinical trials have obtained promising results that focused ultrasound (FUS) combined with microbubbles (MBs) increases tumor uptake and the therapeutic effect of drugs. The aims of the study described here were to investigate whether FUS and MBs could improve the effect of chemotherapy in patients with liver metastases from colorectal cancer and to investigate the safety and feasibility of using FUS + MBs. METHODS: We included 17 patients with liver metastases from colorectal cancer, selected two lesions in each patient's liver and randomized the lesions for, respectively, treatment with FUS + MBs or control. After chemotherapy (FOLFIRI or FOLFOXIRI), the lesions were treated with FUS (frequency = 1.67 MHz, mechanical index = 0.5, pulse repetition frequency = 0.33 Hz, 33 oscillations, duty cycle = 0.2%-0.4% and MBs (SonoVue) for 35 min). Nine boluses of MBs were injected intravenously at 3.5 min intervals. Patients were scheduled for four cycles of treatment. Changes in the size of metastases were determined from computed tomography images. RESULTS: Treatment with FUS + MBs is safe at the settings used. There was considerable variation in treatment response between lesions and mixed response between lesions receiving only chemotherapy. There is a tendency toward larger-volume reduction in lesions treated with FUS + MBs compared with control lesions, but a mixed response to chemotherapy and lesion heterogeneity make it difficult to interpret the results. CONCLUSION: The combination of FUS and MBs is a safe, feasible and available strategy for improving the effect of chemotherapy in cancer patients. Therapeutic effect was not demonstrated in this trial. Multicenter trials with standardized protocols should be performed.

Nanoparticle Dynamics in Composite Hydrogels Exposed to Low-Frequency Focused Ultrasound.

Pulsed focused ultrasound (FUS) in combination with microbubbles has been shown to improve delivery and penetration of nanoparticles in tumors. To understand the mechanisms behind this treatment, it is important to evaluate the contribution of FUS without microbubbles on increased nanoparticle penetration and transport in the tumor extracellular matrix (ECM). A composite agarose hydrogel was made to model the porous structure, the acoustic attenuation and the hydraulic conductivity of the tumor ECM. Single-particle tracking was used as a novel method to monitor nanoparticle dynamics in the hydrogel during FUS exposure. FUS exposure at 1 MHz and 1 MPa was performed to detect any increase in nanoparticle diffusion or particle streaming at acoustic parameters relevant for FUS in combination with microbubbles. Results were compared to a model of acoustic streaming. The nanoparticles displayed anomalous diffusion in the hydrogel, and FUS with a duty cycle of 20% increased the nanoparticle diffusion coefficient by 23%. No increase in diffusion was found for lower duty cycles. FUS displaced the hydrogel itself at duty cycles above 10%; however, acoustic streaming was found to be negligible. In conclusion, pulsed FUS alone cannot explain the enhanced penetration of nanoparticles seen when using FUS and microbubbles for nanoparticle delivery, but it could be used as a tool to enhance diffusion of particles in the tumor ECM.

Hepatic Alarmins and Mitochondrial Dysfunction under Residual Hyperlipidemic Stress Lead to Irreversible NAFLD.

Background and Aims: Nonalcoholic fatty liver disease (NAFLD) includes a range of progressive disorders generated by excess lipid accumulation in the liver leading to hepatic steatosis and eventually fibrosis. We aimed to identify by high performance mass spectrometry-based proteomics the main signaling pathways and liver proteome changes induced by hypercholesterolemia in a rabbit atherosclerotic model that induced high accumulation of lipids in the liver. Methods: The effect of combined lipid-lowering drugs (statins and anti-PCSK9 monoclonal antibody) were used after the interruption of the hypercholesterolemic diet to identify also the potential mediators, such as alarmins, responsible for the irreversible NAFLD build up under the hyperlipidemic sustained stress. Results: Proteomic analysis revealed a number of proteins whose abundance was altered. They were components of metabolic pathways including fatty-acid degradation, glycolysis/gluconeogenesis, and nonalcoholic fatty liver disease. Mitochondrial dysfunction indicated alteration at the mitochondrial respiratory chain level and down-regulation of NADH: ubiquinone oxidoreductase. The expression of a majority of cytochromes (P4502E1, b5, and c) were up-regulated by lipid-lowering treatment. Long-term hyperlipidemic stress, even with a low-fat diet and lipid-lowering treatment, was accompanied by alarmin release (annexins, galectins, HSPs, HMGB1, S100 proteins, calreticulin, and fibronectin) that generated local inflammation and induced liver steatosis and aggressive fibrosis (by high abundance of galectin 3, fibronectin, and calreticulin). Conclusions: The novel findings of this study were related to the residual effects of hyperlipidemic stress with consistent, combined lipid-lowering treatment with statin and inhibitor of PCSK9.

Intravascular targets for molecular contrast-enhanced ultrasound imaging.

Molecular targeting of contrast agents for ultrasound imaging is emerging as a new medical imaging modality. It combines advances in ultrasound technology with principles of molecular imaging, thereby allowing non-invasive assessment of biological processes in vivo. Preclinical studies have shown that microbubbles, which provide contrast during ultrasound imaging, can be targeted to specific molecular markers. These microbubbles accumulate in tissue with target (over) expression, thereby significantly increasing the ultrasound signal. This concept offers safe and low-cost imaging with high spatial resolution and sensitivity. It is therefore considered to have great potential in cancer imaging, and early-phase clinical trials are ongoing. In this review, we summarize the current literature on targets that have been successfully imaged in preclinical models using molecularly targeted ultrasound contrast agents. Based on preclinical experience, we discuss the potential clinical utility of targeted microbubbles.

A multi-pulse ultrasound technique for imaging of thick-shelled microbubbles demonstrated in vitro and in vivo.

Contrast enhanced ultrasound is a powerful diagnostic tool and ultrasound contrast media are based on microbubbles (MBs). The use of MBs in drug delivery applications and molecular imaging is a relatively new field of research which has gained significant interest during the last decade. MBs available for clinical use are fragile with short circulation half-lives due to the use of a thin encapsulating shell for stabilization of the gas core. Thick-shelled MBs can have improved circulation half-lives, incorporate larger amounts of drugs for enhanced drug delivery or facilitate targeting for use in molecular ultrasound imaging. However, methods for robust imaging of thick-shelled MBs are currently not available. We propose a simple multi-pulse imaging technique which is able to visualize thick-shelled polymeric MBs with a superior contrast-to-tissue ratio (CTR) compared to commercially available harmonic techniques. The method is implemented on a high-end ultrasound scanner and in-vitro imaging in a tissue mimicking flow phantom results in a CTR of up to 23 dB. A proof-of-concept study of molecular ultrasound imaging in a soft tissue inflammation model in rabbit is then presented where the new imaging technique showed an enhanced accumulation of targeted MBs in the inflamed tissue region compared to non-targeted MBs and a mean CTR of 13.3 dB for stationary MBs. The presence of fluorescently labelled MBs was verified by confocal microscopy imaging of tissue sections post-mortem.

Regulated cell death joins in atherosclerotic plaque silent progression.

Non-apoptotic regulated cell death (ferroptosis and necroptosis) leads to the release of damage-associated molecular patterns (DAMPs), which initiate and perpetuate a non-infectious inflammatory response. We hypothesize that DAMPs and non-apoptotic regulated cell death are critical players of atherosclerotic plaque progression with inadequate response to lipid-lowering treatment. We aimed to uncover the silent mechanisms that govern the existing residual risk of cardiovascular-related mortality in experimental atherosclerosis. Proteomic and genomic approaches were applied on the ascending aorta of hyperlipidemic rabbits and controls with and without lipid-lowering treatment. The hyperlipidemic animals, which presented numerous heterogeneous atherosclerotic lesions, exhibited high concentrations of serum lipids and increased lipid peroxidation oxidative stress markers. The analyses revealed the significant upregulation of DAMPs and proteins implicated in ferroptosis and necroptosis by hyperlipidemia. Some of them did not respond to lipid-lowering treatment. Dysregulation of five proteins involved in non-apoptotic regulated cell death proteins (VDAC1, VDAC3, FTL, TF and PCBP1) and nine associated DAMPs (HSP90AA1, HSP90AB1, ANXA1, LGALS3, HSP90B1, S100A11, FN, CALR, H3-3A) was not corrected by the treatment. These proteins could play a key role in the atherosclerotic silent evolution and may possess an unexplored therapeutic potential. Mass spectrometry data are available via ProteomeXchange with identifier PXD026379.

Experimental investigation of dynamic real-time rotation-including dose reconstruction during prostate tracking radiotherapy.

BACKGROUND: Hypofractionation in prostate radiotherapy is of increasing interest. Steep dose gradients and a large weight on each individual fraction emphasize the need for motion management. Real-time motion management techniques such as multileaf collimator (MLC) tracking or couch tracking typically adjust for translational motion while rotations remain uncompensated with unknown dosimetric impact. PURPOSE: The purpose of this study is to demonstrate and validate dynamic real-time rotation-including dose reconstruction during radiotherapy experiments with and without MLC and couch tracking. METHODS: Real-time dose reconstruction was performed using the in-house developed software DoseTracker. DoseTracker receives streamed target positions and accelerator parameters during treatment delivery and uses a pencil beam algorithm with water density assumption to reconstruct the dose in a moving target. DoseTracker's ability to reconstruct motion-induced dose errors in a dynamically rotating and translating target was investigated during three different scenarios: (1) no motion compensation and translational motion correction with (2) MLC tracking and (3) couch tracking. In each scenario, dose reconstruction was performed online and in real time during delivery of two dual-arc volumetric-modulated arc therapy prostate plans with a prescribed fraction dose of 7 Gy to the prostate and simultaneous intraprostatic lesion boosts with doses of at least 8 Gy, but up to 10 Gy as long as the organs at risk dose constraints were fulfilled. The plans were delivered to a pelvis phantom that replicated three patient-measured motion traces using a rotational insert with 21 layers of EBT3 film spaced 2.5 mm apart. DoseTracker repeatedly calculated the actual motion-including dose increment and the planned static dose increment since the last calculation in 84 500 points in the film stack. The experiments were performed with a TrueBeam accelerator with MLC and couch tracking based on electromagnetic transponders embedded in the film stack. The motion-induced dose error was quantified as the difference between the final cumulative dose with motion and without motion using the 2D 2%/2 mm γ-failure rate and the difference in dose to 95% of the clinical target volume (CTV ΔD95% ) and the gross target volume (GTV ΔD95% ) as well as the difference in dose to 0.1 cm3 of the urethra, bladder, and rectum (ΔD0.1CC ). The motion-induced errors were compared between dose reconstructions and film measurements. RESULTS: The dose was reconstructed in all calculation points at a mean frequency of 4.7 Hz. The root-mean-square difference between real-time reconstructed and film-measured motion-induced errors was 3.1%-points (γ-failure rate), 0.13 Gy (CTV ΔD95% ), 0.23 Gy (GTV ΔD95% ), 0.19 Gy (urethra ΔD0.1CC ), 0.09 Gy (bladder ΔD0.1CC ), and 0.07 Gy (rectum ΔD0.1CC ). CONCLUSIONS: In a series of phantom experiments, online real-time rotation-including dose reconstruction was performed for the first time. The calculated motion-induced errors agreed well with film measurements. The dose reconstruction provides a valuable tool for monitoring dose delivery and investigating the efficacy of advanced motion-compensation techniques in the presence of translational and rotational motion.