Valentin Djonov

Valentin Djonov
Universität Bern | UniBe · Institute of Anatomy

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372
Publications
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Publications

Publications (372)
Article
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Once considered a waste product of anaerobic cellular metabolism, lactate has been identified as a critical regulator of tumorigenesis, maintenance, and progression. The putative primary function of lactate dehydrogenase B (LDHB) is to catalyze the conversion of lactate to pyruvate; however, its role in regulating metabolism during tumorigenesis is...
Article
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Purpose: Synchrotron-generated microbeam radiotherapy (MRT) represents an innovative preclinical type of cancer radiotherapy with an excellent therapeutic ratio. Beyond local control, metastatic spread is another important endpoint to assess the effectiveness of radiotherapy treatment. Currently, no data exists on an association between MRT and met...
Article
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FLASH radiotherapy (FLASH-RT) and spatially fractionated radiation therapy (SFRT) are two new therapeutical strategies that use non-standard dose delivery methods to reduce normal tissue toxicity and increase the therapeutic index. Although likely based on different mechanisms, both FLASH-RT and SFRT have shown to elicit radiobiological effects tha...
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Acute liver failure (ALF) is a severe and life-threatening condition in which rapid deterioration of liver function develops in a patient who has no preexisting liver disease. Mesenchymal stem cells (MSCs) are immunoregulatory stem cells which are able to modulate phenotype and function of all immune cells that play pathogenic role in the developme...
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Breast cancer is considered refractory to immunotherapy. Accordingly, there is an urgent need for the therapeutic use of new immunostimulatory agents which would enhance antitumor immune response against breast cancer cells. "Derived Multiple Allogeneic Protein Paracrine Signaling (d-MAPPS)" is a biological product whose activity is based on chemok...
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Therapeutic agents that are able to prevent or attenuate inflammation and ischemia-induced injury of neural and retinal cells could be used for the treatment of neural and retinal diseases. Exosomes derived from adipose tissue-sourced mesenchymal stem cells (AT-MSC-Exos) are extracellular vesicles that contain neurotrophins, immunoregulatory and an...
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Radiation therapy (RT) is a vital component of multimodal cancer treatment, and its immunomodulatory effects are a major focus of current therapeutic strategies. Macrophages are some of the first cells recruited to sites of radiation-induced injury where they can aid in tissue repair, propagate radiation-induced fibrogenesis and influence tumour dy...
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Studies have been conducted at synchrotron facilities in Europe and Australia to explore a variety of applications of synchrotron X-rays in medicine and biology. We discuss the major technical aspects of the synchrotron irradiation setups, paying specific attention to the Australian Synchrotron (AS) and the European Synchrotron Radiation Facility (...
Preprint
Once considered a waste product of anaerobic cellular metabolism, lactate has been identified as a critical regulator of tumorigenesis, maintenance, and progression. The putative primary function of lactate dehydrogenase B (LDHB) is to catalyze the conversion of lactate to pyruvate; however, its role in regulating metabolism during tumorigenesis is...
Article
Full-text available
Introduction This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. Methods A temporal bone was used to verify the acc...
Article
Due to their immunoregulatory properties and capacity for multi-lineage differentiation, mesenchymal stem cells (MSCs) have been used as new therapeutic agents in regenerative medicine. Numerous lifestyle habits and behavioral risk factors may modulate metabolic and cell growth signaling pathways in MSCs, affecting their phenotype and function. Acc...
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Mesenchymal stem cells (MSCs) are self-renewable, multipotent stem cells that regulate the phenotype and function of all immune cells that participate in anti-tumor immunity. MSCs modulate the antigen-presenting properties of dendritic cells, affect chemokine and cytokine production in macrophages and CD4+ T helper cells, alter the cytotoxicity of...
Article
Microbeam radiation therapy, an alternative radiosurgical treatment under preclinical investigation, aims to safely treat muzzle tumors in pet animals. This will require data on the largely unknown radiation toxicity of microbeam arrays for bones and teeth. To this end, the muzzle of six young adult New Zealand rabbits was irradiated by a lateral a...
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Conventional radiotherapy is a widely used non-invasive form of treatment for many types of cancer. However, due to a low threshold in the lung for radiation-induced normal tissue damage, it is of less utility in treating lung cancer. For this reason, surgery is the preferred treatment for lung cancer, which has the detriment of being highly invasi...
Article
Full-text available
Mesenchymal stem cells (MSCs), due to their potential for differentiation into alveolar epithelial cells and their immunosuppressive characteristics, are considered a new therapeutic agent in cell-based therapy of inflammatory lung disorders, including chronic obstructive pulmonary disease (COPD). Since most of the MSC-mediated beneficent effects w...
Article
Purpose This study provides the first experimental application of multiscale three-dimensional (3D) X-ray Phase Contrast Imaging Computed Tomography (XPCI-CT) virtual histology for the inspection and quantitative assessment of the late stage effects of radio-induced lesions on lungs in a small animal model. Methods and Materials Healthy male Fisch...
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Although well investigated, the importance of collagen fibers in supporting angiogenesis is not well understood. In this study, we demonstrate that extracellular collagen fibers provide guidance cues for endothelial cell migration during regenerative angiogenesis in the caudal zebrafish fin. Inhibition of collagen cross-linking by β-Aminopropionitr...
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Purpose In the last three decades, Synchrotron Microbeam Radiation Therapy (S-MRT) has been shown to achieve both good tumour control and normal tissue sparing in a range of pre-clinical animal models. However, the use of S-MRT for the treatment of lung tumours has not yet been investigated. This study is the first to evaluate the therapeutic effic...
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More VEGF, more life—and health span Advanced aging is celebrated but its ill effects, deterioration at the cell, tissue, and organ levels, are not. Grunewald et al . provide evidence for the vascular theory of aging, which reports that age-related decrease of vascular function is a driver of organismal aging at large (see the Perspective by August...
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Melanoma is the deadliest type of skin cancer, due to its invasiveness and limited treatment efficacy. The main therapy for primary melanoma and solitary organ metastases is wide excision. Adjuvant therapy, such as chemotherapy and targeted therapies are mainly used for disseminated disease. Radiotherapy (RT) is a powerful treatment option used in...
Article
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Synchrotron radiation, especially microbeam radiotherapy (MRT), has a great potential to improve cancer radiotherapy, but non-targeted effects of synchrotron radiation have not yet been sufficiently explored. We have previously demonstrated that scattered synchrotron radiation induces measurable γ-H2AX foci, a biomarker of DNA double-strand breaks,...
Article
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Background: Microbeam Radiation Therapy (MRT) induces a transient vascular permeability window, which offers a novel drug-delivery system for the preferential accumulation of therapeutic compounds in tumors. MRT is a preclinical cancer treatment modality that spatially fractionates synchrotron X-rays into micrometer-wide planar microbeams which ca...
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Mesenchymal stem cells (MSCs) are adult, immunomodulatory stem cells which reside in almost all postnatal tissues. Viral antigens and damage-associated molecular patterns released from injured and infected cells activate MSCs, which elicit strong antiviral immune response. MSC-sourced interferons and inflammatory cytokines modulate the cytotoxicity...
Article
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Mesenchymal stem cells (MSCs) are self-renewable, rapidly proliferating, multipotent stem cells which reside in almost all post-natal tissues. MSCs possess potent immunoregulatory properties and, in juxtacrine and paracrine manner, modulate phenotype and function of all immune cells that participate in tissue repair and regeneration. Additionally,...
Article
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Mesenchymal stem cell (MSC)-derived exosomes (MSC-Exo) are nano-sized extracellular vesicles enriched with MSC-sourced neuroprotective and immunomodulatory microRNAs, neural growth factors, and anti-inflammatory cytokines, which attenuate neuro-inflammation, promote neo-vascularization, induce neurogenesis, and reduce apoptotic loss of neural cells...
Preprint
Full-text available
OBJECTIVE The following study investigates whether human Thiel-embalmed temporal bones are suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and the effect of solid iodine staining for improved visualization and facilitated segmentation of middle ear structures. METHODS One temporal bone was used t...
Article
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Analysis of the angioarchitecture and quantification of the conduit vessels and microvasculature is of paramount importance for understanding the physiological and pathological processes within the central nervous system (CNS). Most of the available in vivo imaging methods lack penetration depth and/or resolution. Some ex vivo methods may provide b...
Article
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Purpose Radiotherapy is an important treatment component for patients with lung cancer. However, the survival time gained with clinical radiotherapy techniques is relatively short. Data from pre-clinical experiments suggest that synchrotron microbeam radiotherapy (MRT) could be much better suited to control malignant brain tumours than current clin...
Article
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent responsible for the development of a new coronavirus disease (COVID-19), is a highly transmittable virus which, in just ten months, infected more than 40 million people in 214 countries worldwide. After inhalation, aerosols containing SARS-CoV-2 penetrate to the dep...
Article
Background: Recent discoveries have indicated that, in the developing heart, sinus venosus and endocardium provide major sources of endothelium for coronary vessel growth that supports the expanding myocardium. Here we set out to study the origin of the coronary vessels that develop in response to vascular endothelial growth factor B (VEGF-B) in th...
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Introduction: In order to achieve a satisfactory functional and aesthetic result a thin skin flap is often required in surgical reconstruction of various body regions. Perforator flaps based on either the superficial or deep branch of the superficial circumflex iliac artery (SCIA) have been used for this purpose mainly in the Asian population. Rece...
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IVIG preparations consisting of pooled IgG are increasingly used for the treatment of autoimmune diseases. IVIG is known to regulate the viability of immune cells, including neutrophils. We report that plasma-derived IgA efficiently triggers death of neutrophils primed by cytokines or TLR agonists. IgA-mediated programmed neutrophil death was PI3K-...
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Background: Synchrotron Microbeam Radiotherapy (MRT) significantly improves local tumour control with minimal normal tissue toxicity. MRT delivers orthovoltage X-rays at an ultra-high "FLASH" dose rate in spatially fractionated beams, typically only few tens of micrometres wide. One of the biggest challenges in translating MRT to the clinic is its...
Article
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There is still a lively debate about whether mesenchymal stem cells (MSCs) promote or suppress antitumor immune response. Although several possible explanations have been proposed, including different numbers of injected and engrafted MSCs, heterogeneity in phenotype, and function of tumor cells, the exact molecular mechanisms responsible for oppos...
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Background Lateral sliding calcaneus osteotomies are common procedures to correct hindfoot varus deformities. Shifting the calcaneal tuberosity laterally (lateralization) can lead to tarsal tunnel pressure increase and tibial nerve palsy. The purpose of this cadaveric biomechanical study was to investigate the correlation of lateralization and pres...
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Endophilin B1, also known as BAX-interacting protein 1 (BIF-1), is part of the endophilin B protein family, and is a multifunctional protein involved in the regulation of apoptosis, autophagy, and mitochondrial morphology. The role of BIF-1 in cancer is controversial since previous reports indicated to both tumor-promoting and tumor-suppressive rol...
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Mesenchymal stem cells (MSC) are, due to their immunosuppressive and regenerative properties, used as new therapeutic agents in cell-based therapy of inflammatory and degenerative diseases. A large number of experimental and clinical studies revealed that most of MSC-mediated beneficial effects were attributed to the effects of MSC-sourced exosomes...
Article
The autonomic nerves of the lesser pelvis are particularly prone to iatrogenic lesions due to their exposed position during manifold surgical interventions. Nevertheless, the cause of rectal and urinary incontinence or sexual dysfunctions, for example after rectal cancer resection or hysterectomy, remains largely understudied, particularly with reg...
Article
Overview The National Cancer Institute’s Radiation Research Program in collaboration with the Radiosurgery Society hosted a workshop on Understanding High-Dose, Ultra-High Dose rate and Spatially Fractionated Radiotherapy on August 20-21, 2018 to bring together experts in experimental and clinical experience in these and related fields. Critically,...
Article
Full-text available
Mesenchymal stem cells (MSCs), due to their potential for differentiation into alveolar epithelial cells and their immunosuppressive characteristics, are considered a new therapeutic agent in cell-based therapy of inflammatory lung disorders, including chronic obstructive pulmonary disease (COPD). Since most of the MSC-mediated beneficent effects w...
Article
Full-text available
Background: Microbeam Radiation Therapy (MRT) is an innovative approach in radiation oncology where a collimator subdivides the homogeneous radiation field into an array of co-planar, high-dose beams which are tens of micrometres wide and separated by a few hundred micrometres. Objective: This scoping review was conducted to map the available ev...
Article
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In order to study the adaptation scope of the fish respiratory organ and the O2 metabolism due to endurance training, we subjected adult zebrafish (Danio rerio) to endurance exercise for 5 weeks. After the training period, the swimmer group showed a significant increase in swimming performance, body weight and length. In scanning electron microscop...
Article
Purpose: Synchrotron microbeam radiation therapy (MRT) is based on the spatial fractionation of the incident, highly collimated synchrotron beam into arrays of parallel microbeams depositing several hundred grays. It appears relevant to combine MRT with a conventional treatment course, preparing a treatment scheme for future patients in clinical t...
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Objective: To study two major molecular alterations in spontaneous abortions (SA) with unexplained etiology - fetal genomic anomalies and the endometrial expression of main angiogenic factors VEGFA/VEGFR2 and chemokines SDF-1/CXCR4. Materials and methods: Whole genome copy number analysis by arrayCGH or Next Generation Sequencing (NGS) was appli...
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Glaucoma represents a group of progressive optic neuropathies characterized by gradual loss of retinal ganglion cells (RGCs), the neurons that conduct visual information from the retina to the brain. Elevated intraocular pressure (IOP) is considered the main reason for enhanced apoptosis of RGCs in glaucoma. Currently used therapeutic agents are no...
Article
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There is growing evidence that mesenchymal stem cell (MSC)-based immunosuppression was mainly attributed to the effects of MSC-derived extracellular vesicles (MSC-EVs). MSC-EVs are enriched with MSC-sourced bioactive molecules (messenger RNA (mRNA), microRNAs (miRNAs), cytokines, chemokines, immunomodulatory factors) that regulate phenotype, functi...
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Background Cisplatin (cis-diamminedichloroplatinum II, CDDP) is one of the most effective chemotherapeutic agents. However, its clinical use is limited due to the severe side effects, including nephrotoxicity and acute kidney injury (AKI) which develop due to renal accumulation and biotransformation of CDDP. The alleviation or prevention of CDDP-ca...
Article
In contrast to the “Warburg effect” or aerobic glycolysis earlier generalized as a phenomenon in cancer cells, more and more recent evidence indicates that functional mitochondria are pivotal for ensuring the energy supply of cancer cells. Here, we report that cancer cells with reduced autophagy-related protein 12 (ATG12) expression undergo an onco...