ResearchPad - laboratory-investigation https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Spine Computed Tomography to Magnetic Resonance Image Synthesis Using Generative Adversarial Networks : A Preliminary Study]]> https://www.researchpad.co/article/elastic_article_11307 To generate synthetic spine magnetic resonance (MR) images from spine computed tomography (CT) using generative adversarial networks (GANs), as well as to determine the similarities between synthesized and real MR images. MethodsGANs were trained to transform spine CT image slices into spine magnetic resonance T2 weighted (MRT2) axial image slices by combining adversarial loss and voxel-wise loss. Experiments were performed using 280 pairs of lumbar spine CT scans and MRT2 images. The MRT2 images were then synthesized from 15 other spine CT scans. To evaluate whether the synthetic MR images were realistic, two radiologists, two spine surgeons, and two residents blindly classified the real and synthetic MRT2 images. Two experienced radiologists then evaluated the similarities between subdivisions of the real and synthetic MRT2 images. Quantitative analysis of the synthetic MRT2 images was performed using the mean absolute error (MAE) and peak signal-to-noise ratio (PSNR). ResultsThe mean overall similarity of the synthetic MRT2 images evaluated by radiologists was 80.2%. In the blind classification of the real MRT2 images, the failure rate ranged from 0% to 40%. The MAE value of each image ranged from 13.75 to 34.24 pixels (mean, 21.19 pixels), and the PSNR of each image ranged from 61.96 to 68.16 dB (mean, 64.92 dB). ConclusionThis was the first study to apply GANs to synthesize spine MR images from CT images. Despite the small dataset of 280 pairs, the synthetic MR images were relatively well implemented. Synthesis of medical images using GANs is a new paradigm of artificial intelligence application in medical imaging. We expect that synthesis of MR images from spine CT images using GANs will improve the diagnostic usefulness of CT. To better inform the clinical applications of this technique, further studies are needed involving a large dataset, a variety of pathologies, and other MR sequence of the lumbar spine. ]]> <![CDATA[<i>In-Vitro</i> Study of Urokinase Thrombolysis Following Stereotactic Aspiration of Intracerebral Hematoma]]> https://www.researchpad.co/article/elastic_article_11302 A consensus regarding the ideal regimen for urokinase (UK) thrombolysis subsequent to stereotactic spontaneous intracerebral hemorrhage aspiration has yet to be established. The purpose of this study is to evaluate the efficacy of UK thrombolysis relative to when the regimen is changed. MethodsVenous blood from 30 heathy volunteers was obtained for this in-vitro study. Various concentrations of UK solution were added to microcentrifuge tubes containing the clotted blood. The efficacy of UK thrombolysis was identified by checking the weight of lysed hematoma following various time intervals with different concentrations of UK solution. Group one, the “3×4” group involved four administrations every 3 hours over 12 hours, and group two, the “6×2” group involved two administrations every 6 hours over 12 hours. ResultsMore hematoma was lysed in the 3×4 group than the 6×2 group across all concentration levels (however, the differences were only significant between groups at the 500 and 1000 IU concentration levels, p<0.05). There were no significant differences of lysed hematoma among the various UK solution concentrations within groups. ConclusionThis study suggests that frequent administrations of UK thrombolysis may result in a greater degree of lysed hematoma in comparison to a higher concentration of UK. ]]> <![CDATA[Preclinical evaluation of binimetinib (MEK162) delivered via polymeric nanocarriers in combination with radiation and temozolomide in glioma]]> https://www.researchpad.co/article/Nba7b0369-1d79-4804-9b6a-a9b172dd871f

Background and purpose

Glioblastoma multiforme (GBM) is the most aggressive subtype of malignant gliomas, with an average survival rate of 15 months after diagnosis. More than 90% of all GBMs have activating mutations in the MAPK/ERK pathway. Recently, we showed the allosteric MEK1/2 inhibitor binimetinib (MEK162) to inhibit cell proliferation and to enhance the effect of radiation in preclinical human GBM models. Because the free drug cannot pass the blood–brain barrier (BBB), we investigated the use of nanocarriers for transport of the drug through the BBB and its efficacy when combined with radiotherapy and temozolomide (TMZ) in glioma spheroids.

Methods

In vitro studies were performed using multicellular U87 human GBM spheroids. Polymeric nanocarriers (polymersomes) were loaded with MEK162. The interaction between nanocarrier delivered MEK162, irradiation and TMZ was studied on the kinetics of spheroid growth and on protein expression in the MAPK/ERK pathway. BBB passaging was evaluated in a transwell system with human cerebral microvascular endothelial (hCMEC/D3) cells.

Results

MEK162 loaded polymersomes inhibited spheroid growth. A synergistic effect was found in combination with fractionated irradiation and an additive effect with TMZ on spheroid volume reduction. Fluorescent labeled polymersomes were taken up by human cerebral microvascular endothelial cells and passed the BBB in vitro.

Conclusion

MEK162 loaded polymersomes are taken up by multicellular spheroids. The nanocarrier delivered drug reduced spheroid growth and inhibited its molecular target. MEK162 delivered via polymersomes showed interaction with irradiation and TMZ. The polymersomes crossed the in vitro BBB model and therewith offer exciting challenges ahead for delivery of therapeutics agents to brain tumours.

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<![CDATA[Carnosic acid potentiates the anticancer effect of temozolomide by inducing apoptosis and autophagy in glioma]]> https://www.researchpad.co/article/5c6db113d5eed0c48450cc1c

Objective

Malignant glioma is a lethal brain tumor with a low survival rate and poor prognosis. New strategies are urgently needed to augment the chemotherapeutic effects of temozolomide (TMZ), the standard drug in glioma treatment. Carnosic acid (CA) has been reported to have anticancer, antioxidant and anti-infectious properties. In this study, we aimed to investigate the anticancer effects and the underlying mechanisms of CA in combination with TMZ in glioma cancer cells.

Methods

The glioma cancer cells were treated with TMZ, CA, or TMZ + CA. We evaluated cell survival by CCK-8 assay, cell anchorage-independent survival by colony formation assay, cell migration by wound-healing assay, cell cycle and cell apoptosis by flow cytometry, and protein expression by western blot.

Results

CA enhanced the cytotoxic effect of TMZ in glioma cancer cells. CA enhanced TMZ-induced inhibition of colony formation and cell migration and enhanced TMZ-induced cell cycle arrest and cellular apoptosis. Immunofluorescence suggested that CA in combination with TMZ triggered autophagy. Furthermore, CA promoted TMZ-induced cell cycle arrest and cellular apoptosis by Cyclin B1 inhibition and activation of PARP and Caspase-3, while CA promoted TMZ-induced cellular autophagy by p-AKT inhibition, p62 downregulation and LC3-I to LC3-II transition.

Conclusion

These data suggest that the combination therapy of CA and TMZ strengthens the anticancer effect of TMZ by enhancing apoptosis and autophagy.

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<![CDATA[Epithelial growth factor receptor expression influences 5-ALA induced glioblastoma fluorescence]]> https://www.researchpad.co/article/5b41f5c8463d7e0fad551d13

The extent of 5-aminolevulinic acid (5-ALA) guided tumor resection has a determining impact in high-grade glioma and glioblastoma surgery. Yet the intensity of the 5-ALA induced fluorescence may vary within the tumor. We aimed to correlate 5-ALA induced fluorescence with the expression of epithelial growth factor receptor (EGFR) and its constitutively active version EGFRvIII in different glioblastoma (GBM) cell lines. To elucidate the role of EGFR in the metabolism of 5-ALA in GBM cell lines with variable EGFR expression status, we analyzed the activation of EGFR by its primary ligand EGF, and its downstream effect on Heme oxygenase-1 (HO-1), a key enzyme regulating the metabolism of Protoporphyrin IX (PpIX), the fluorescent metabolite of 5-ALA. Effects of direct pharmacological inhibition by Tin(IV)-Protoporphyrin (SnPP) or gene knockdown by small interfering RNA (siRNA) on HO-1 enzyme were analyzed in respect to 5-ALA induced fluorescence. Furthermore, inhibition of EGFR by Gefitinib was tested. A significant difference in 5-ALA induced fluorescence was obtained in U87MG (low EGFR expression) and LN229EGFR cells (EGFR overexpression) compared to BS153 (EGFR overexpression/EGFRvIII+). Treatment of U87MG and LN229EGFR cells with EGF significantly reduced cellular fluorescence, by promoting HO-1 transcription and expression in a concentration-dependent manner. This effect could be reversed by EGFR-specific siRNA treatment, which reduced protein expression of about 80% in U87MG. Remarkably, inhibition of HO-1 activity by SnPP or reduction of HO-1 protein levels by siHO-1 treatment restored fluorescence in all cell lines, independently of EGFR quantitative and qualitative expression. Gefitinib treatment was able to restore fluorescence after EGF stimulation in U87MG cells but not in BS153 cells, overexpressing EGFR/EGFRvIII. In GBM cell lines, 5-ALA induced fluorescence is variable and influenced by EGF-induced downstream activation of HO-1. HO-1 protein expression was identified as a negative regulator of 5-ALA induced fluorescence in GBM cells. We further propose that co-expression of EGFRvIII but not quantitative EGFR expression influence HO-1 activity and therefore cellular fluorescence.

Electronic supplementary material

The online version of this article (doi:10.1007/s11060-017-2474-0) contains supplementary material, which is available to authorized users.

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