233 research outputs found
Unenhanced helical computed tomography vs intravenous urography in patients with acute flank pain: accuracy and economic impact in a randomized prospective trial
Abstract.: Unenhanced helical computed tomography (UHCT) has evolved into a well-accepted alternative to intravenous urography (IVU) in patients with acute flank pain and suspected ureterolithiasis. The purpose of our randomized prospective study was to analyse the diagnostic accuracy of UHCT vs IVU in the normal clinical setting with special interest on economic impact, applied radiation dose and time savings in patient management. A total of 122 consecutive patients with acute flank pain suggestive of urolithiasis were randomized for UHCT (n=59) or IVU (n=63). Patient management (time, contrast media), costs and radiation dose were analysed. The films were independently interpreted by four radiologists, unaware of previous findings, clinical history and clinical outcome. Alternative diagnoses if present were assessed. Direct costs of UHCT and IVU are nearly identical (310/309 Euro). Indirect costs are much lower for UHCT because it saves examination time and when performed immediately initial abdominal plain film (KUB) and sonography are not necessary. Time delay between access to the emergency room and start of the imaging procedure was 32h 7min for UHCT and 36h 55min for IVU. The UHCT took an average in-room time of 23min vs 1h 21min for IVU. Mild to moderate adverse reactions for contrast material were seen in 3 (5%) patients. The UHCT was safe, as no contrast material was needed. The mean applied radiation dose was 3.3mSv for IVU and 6.5mSv for UHCT. Alternative diagnoses were identified in 4 (7%) UHCT patients and 3 (5%) IVU patients. Sensitivity and specificity of UHCT and IVU was 94.1 and 94.2%, and 85.2 and 90.4%, respectively. In patients with suspected renal colic KUB and US may be the least expensive and most easily accessable modalities; however, if needed and available, UHCT can be considered a better alternative than IVU because it has a higher diagnostic accuracy and a better economic impact since it is more effective, faster, less expensive and less risky than IVU. In addition, it also has the capability of detecting various additional renal and extrarenal pathologie
Redox signals at the ER-mitochondria interface control melanoma progression.
Reactive oxygen species (ROS) are emerging as important regulators of cancer growth and metastatic spread. However, how cells integrate redox signals to affect cancer progression is not fully understood. Mitochondria are cellular redox hubs, which are highly regulated by interactions with neighboring organelles. Here, we investigated how ROS at the endoplasmic reticulum (ER)-mitochondria interface are generated and translated to affect melanoma outcome. We show that TMX1 and TMX3 oxidoreductases, which promote ER-mitochondria communication, are upregulated in melanoma cells and patient samples. TMX knockdown altered mitochondrial organization, enhanced bioenergetics, and elevated mitochondrial- and NOX4-derived ROS. The TMX-knockdown-induced oxidative stress suppressed melanoma proliferation, migration, and xenograft tumor growth by inhibiting NFAT1. Furthermore, we identified NFAT1-positive and NFAT1-negative melanoma subgroups, wherein NFAT1 expression correlates with melanoma stage and metastatic potential. Integrative bioinformatics revealed that genes coding for mitochondrial- and redox-related proteins are under NFAT1 control and indicated that TMX1, TMX3, and NFAT1 are associated with poor disease outcome. Our study unravels a novel redox-controlled ER-mitochondria-NFAT1 signaling loop that regulates melanoma pathobiology and provides biomarkers indicative of aggressive disease
Protein Kinase CK2 Regulates Nerve/Glial Antigen (NG)2-Mediated Angiogenic Activity of Human Pericytes
Protein kinase CK2 is a crucial regulator of endothelial cell proliferation, migration and
sprouting during angiogenesis. However, it is still unknown whether this kinase additionally affects
the angiogenic activity of other vessel-associated cells. In this study, we investigated the effect of
CK2 inhibition on primary human pericytes. We found that CK2 inhibition reduces the expression of
nerve/glial antigen (NG)2, a crucial factor which is involved in angiogenic processes. Reporter gene
assays revealed a 114 bp transcriptional active region of the human NG2 promoter, whose activity
was decreased after CK2 inhibition. Functional analyses demonstrated that the pharmacological
inhibition of CK2 by CX-4945 suppresses pericyte proliferation, migration, spheroid sprouting and
the stabilization of endothelial tubes. Moreover, aortic rings of NG2â/â mice showed a significantly
reduced vascular sprouting when compared to rings of NG2+/+ mice, indicating that NG2 is an
important regulator of the angiogenic activity of pericytes. In vivo, implanted Matrigel plugs
containing CX-4945-treated pericytes exhibited a lower microvessel density when compared to
controls. These findings demonstrate that CK2 regulates the angiogenic activity of pericytes through
NG2 gene expression. Hence, the inhibition of CK2 represents a promising anti-angiogenic strategy,
because it does not only target endothelial cells, but also vessel-associated pericytes
CK2 Activity Mediates the Aggressive Molecular Signature of Glioblastoma Multiforme by Inducing Nerve/Glial Antigen (NG)2 Expression
Nerve/glial antigen (NG)2 expression crucially determines the aggressiveness of glioblastoma multiforme (GBM). Recent evidence suggests that protein kinase CK2 regulates NG2 expression.
Therefore, we investigated in the present study whether CK2 inhibition suppresses proliferation
and migration of NG2-positive GBM cells. For this purpose, CK2 activity was suppressed in the
NG2-positive cell lines A1207 and U87 by the pharmacological inhibitor CX-4945 and CRISPR/Cas9-
mediated knockout of CK2α. As shown by quantitative real-time PCR, luciferase-reporter assays,
flow cytometry and western blot, this significantly reduced NG2 gene and protein expression when
compared to vehicle-treated and wild type controls. In addition, CK2 inhibition markedly reduced
NG2-dependent A1207 and U87 cell proliferation and migration. The Cancer Genome Atlas (TCGA)-
based data further revealed not only a high expression of both NG2 and CK2 in GBM but also
a positive correlation between the mRNA expression of the two proteins. Finally, we verified a
decreased NG2 expression after CX-4945 treatment in patient-derived GBM cells. These findings
indicate that the inhibition of CK2 represents a promising approach to suppress the aggressive
molecular signature of NG2-positive GBM cells. Therefore, CX-4945 may be a suitable drug for the
future treatment of NG2-positive GBM
Inhibition of CK2 Reduces NG2 Expression in Juvenile Angiofibroma
Juvenile angiofibroma (JA) is a rare fibrovascular neoplasm predominately found within the
posterior nasal cavity of adolescent males. JA expresses the proteoglycan nerveâglial antigen (NG)2,
which crucially determines the migratory capacity of distinct cancer cells. Moreover, it is known that
the protein kinase CK2 regulates NG2 gene expression. Therefore, in the present study, we analyzed
whether the inhibition of CK2 suppresses NG2-dependent JA cell proliferation and migration. For
this purpose, we assessed the expression of NG2 and CK2 in patient-derived JA tissue samples, as
well as in patient-derived JA cell cultures by Western blot, immunohistochemistry, flow cytometry
and quantitative real-time PCR. The mitochondrial activity, proliferation and migratory capacity
of the JA cells were determined by water-soluble tetrazolium (WST)-1, 5-bromo-20
-deoxyuridine
(BrdU) and collagen sprouting assays. We found that NG2 and CK2 were expressed in both the JA
tissue samples and cell cultures. The treatment of the JA cells with the two CK2 inhibitors, CX-4945
and SGC-CK2-1, significantly reduced NG2 gene and protein expression when compared to the
vehicle-treated cells. In addition, the loss of CK2 activity suppressed the JA cell proliferation and
migration. These findings indicate that the inhibition of CK2 may represent a promising therapeutic
approach for the treatment of NG2-expressing JA
Local Application of Mineral-Coated Microparticles Loaded With VEGF and BMP-2 Induces the Healing of Murine Atrophic Non-Unions
Deficient angiogenesis and disturbed osteogenesis are key factors for the development of
nonunions. Mineral-coated microparticles (MCM) represent a sophisticated carrier system
for the delivery of vascular endothelial growth factor (VEGF) and bone morphogenetic
protein (BMP)-2. In this study, we investigated whether a combination of VEGF- and BMP2-loaded MCM (MCM + VB) with a ratio of 1:2 improves bone repair in non-unions. For this
purpose, we applied MCM + VB or unloaded MCM in a murine non-union model and
studied the process of bone healing by means of radiological, biomechanical,
histomorphometric, immunohistochemical and Western blot techniques after 14 and
70 days. MCM-free non-unions served as controls. Bone defects treated with MCM +
VB exhibited osseous bridging, an improved biomechanical stiffness, an increased bone
volume within the callus including ongoing mineralization, increased vascularization, and a
histologically larger total periosteal callus area consisting predominantly of osseous tissue
when compared to defects of the other groups. Western blot analyses on day 14 revealed
a higher expression of osteoprotegerin (OPG) and vice versa reduced expression of
receptor activator of NF-ÎșB ligand (RANKL) in bone defects treated with MCM + VB. On
day 70, these defects exhibited an increased expression of erythropoietin (EPO), EPOreceptor and BMP-4. These findings indicate that the use of MCM for spatiotemporal
controlled delivery of VEGF and BMP-2 shows great potential to improve bone healing in
atrophic non-unions by promoting angiogenesis and osteogenesis as well as reducing
early osteoclast activity
Antimargination of microparticles and platelets in the vicinity of branching vessels
We investigate the margination of microparticles/platelets in blood flow
through complex geometries typical for in vivo vessel networks: a vessel
confluence and a bifurcation. Using 3D Lattice-Boltzmann simulations, we
confirm that behind the confluence of two vessels a cell-free layer devoid of
red blood cells develops in the channel center. Despite its small size of
roughly one micrometer, this central cell-free layer persists for up to 100
m after the confluence. Most importantly, we show from simulations that
this layer also contains a significant amount of microparticles/platelets and
validate this result by in vivo microscopy in mouce venules. At bifurcations,
however, a similar effect does not appear and margination is largely unaffected
by the geometry. This anti-margination towards the vessel center after a
confluence may explain in vivo observations by Woldhuis et al. [Am. J. Physiol.
262, H1217 (1992)] where platelet concentrations near the vessel wall are seen
to be much higher on the arteriolar side (containing bifurcations) than on the
venular side (containing confluences) of the vascular system
Hypoxia-induced downregulation of microRNA-186-5p in endothelial cells promotes non-small cell lung cancer angiogenesis by upregulating protein kinase C alpha
The tumor microenvironment stimulates the angiogenic activity of endothelial cells (ECs) to facilitate tumor vascularization,
growth, and metastasis. The involvement of microRNA-186-5p
(miR-186) in regulating the aberrant activity of tumor-associated ECs has so far not been clarified. In the present study,
we demonstrated that miR-186 is significantly downregulated
in ECs microdissected from human non-small cell lung cancer
(NSCLC) tissues compared with matched non-malignant lung
tissues. In vitro analyses of primary human dermal microvascular ECs (HDMECs) exposed to different stimuli indicated
that this miR-186 downregulation is triggered by hypoxia
via activation of hypoxia-inducible factor 1 alpha (HIF1a).
Transfection of HDMECs with miR-186 mimic (miR-186m)
significantly inhibited their proliferation, migration, tube
formation, and spheroid sprouting. In contrast, miR-186
inhibitor (miR-186i) exerted pro-angiogenic effects. In vivo,
endothelial miR-186 overexpression inhibited the vascularization of Matrigel plugs and the initial growth of tumors
composed of NSCLC cells (NCI-H460) and HDMECs. Mechanistic analyses revealed that the gene encoding for protein
kinase C alpha (PKCa) is a bona fide target of miR-186. Activation of this kinase significantly reversed the miR-186mrepressed angiogenic activity of HDMECs. These findings
indicate that downregulation of miR-186 in ECs mediates hypoxia-stimulated NSCLC angiogenesis by upregulating PKCa
Improvement of islet transplantation by the fusion of islet cells with functional blood vessels
Pancreatic islet transplantation still represents a promising therapeutic strategy for curative treatment of type 1 diabetes mellitus. However, a limited number of organ donors and insufficient vascularization with islet engraftment failure restrict the successful transfer of this approach into clinical practice. To overcome these problems, we herein introduce a novel strategy for the generation of prevascularized islet organoids by the fusion of pancreatic islet cells with functional native microvessels. These insulin-secreting organoids exhibit a significantly higher angiogenic activity compared to freshly isolated islets, cultured islets, and non-prevascularized islet organoids. This is caused by paracrine signaling between the ÎČ-cells and the microvessels, mediated by insulin binding to its corresponding receptor on endothelial cells. In vivo, the prevascularized islet organoids are rapidly blood-perfused after transplantation by the interconnection of their autochthonous microvasculature with surrounding blood vessels. As a consequence, a lower number of islet grafts are required to restore normoglycemia in diabetic mice. Thus, prevascularized islet organoids may be used to improve the success rates of clinical islet transplantation
Transport of small anionic and neutral solutes through chitosan membranes: Dependence on cross-linking and chelation of divalent cations
Chitosan membranes were prepared by solvent casting and cross-linked with glutaraldehyde at several ratios
under homogeneous conditions. The cross-linking degree, varying from 0 to 20%, is defined as the ratio between
the total aldehyde groups and the amine groups of chitosan. Permeability experiments were conducted using a
side-by-side diffusion cell to determine the flux of small molecules of similar size but with different chemical
moieties, either ionized (benzoic acid, salicylic acid, and phthalic acid) or neutral (2-phenylethanol) at physiological
pH. The permeability of the different model molecules revealed to be dependent on the affinity of those structurally
similar molecules to chitosan. The permeability of the salicylate anion was significantly enhanced by the presence
of metal cations commonly present in biological fluids, such as calcium and magnesium, but remained unchanged
for the neutral 2-phenylethanol. This effect could be explained by the chelation of metal cations on the amine
groups of chitosan, which increased the partition coefficient. The cross-linking degree was also correlated with
the permeability and partition coefficient. The change in the permeation properties of chitosan to anionic solutes
in the presence of these metallic cations is an important result and should be taken into consideration when trying
to make in vitro predictions of the drug release from chitosan-based controlled release systems
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