Clinical usability of 3D gradient-echo-based ultrashort echo time imaging: Is it enough to facilitate diagnostic decision in real-world practice?

BACKGROUND: With recent advances in magnetic resonance imaging (MRI) technology, the practical role of lung MRI is expanding despite the inherent challenges of the thorax. The purpose of our study was to evaluate the current status of the concurrent dephasing and excitation (CODE) ultrashort echo-time sequence and the T1-weighted volumetric interpolated breath-hold examination (VIBE) sequence in the evaluation of thoracic disease by comparing it with the gold standard computed tomography (CT). METHODS: Twenty-four patients with lung cancer and mediastinal masses underwent both CT and MRI including T1-weighted VIBE and CODE. For CODE images, data were acquired in free breathing and end-expiratory images were reconstructed using retrospective respiratory gating. All images were evaluated through qualitative and quantitative approaches regarding various anatomical structures and lesions (nodule, mediastinal mass, emphysema, reticulation, honeycombing, bronchiectasis, pleural plaque and lymphadenopathy) inside the thorax in terms of diagnostic performance in making specific decisions. RESULTS: Depiction of the lung parenchyma, mediastinal and pleural lesion was not significant different among the three modalities (p > 0.05). Intra-tumoral and peritumoral features of lung nodules were not significant different in the CT, VIBE or CODE images (p > 0.05). However, VIBE and CODE had significantly lower image quality and poorer depiction of airway, great vessels, and emphysema compared to CT (p < 0.05). Image quality of central airways and depiction of bronchi were significantly better in CODE than in VIBE (p < 0.001 and p = 0.005). In contrast, the depiction of the vasculature was better for VIBE than CODE images (p = 0.003). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were significant greater in VIBE than CODE except for SNRlung and SNRnodule (p < 0.05). CONCLUSIONS: Our study showed the potential of CODE and VIBE sequences in the evaluation of localized thoracic abnormalities including solid pulmonary nodules.

Novel rAAV vector mediated intrathecal HGF delivery has an impact on neuroimmune modulation in the ALS motor cortex with TDP-43 pathology.

Recombinant adeno-associated virus (rAAV)-based gene therapies offer an immense opportunity for rare diseases, such as amyotrophic lateral sclerosis (ALS), which is defined by the loss of the upper and the lower motor neurons. Here, we describe generation, characterization, and utilization of a novel vector system, which enables expression of the active form of hepatocyte growth factor (HGF) under EF-1α promoter with bovine growth hormone (bGH) poly(A) sequence and is effective with intrathecal injections. HGF's role in promoting motor neuron survival had been vastly reported. Therefore, we investigated whether intrathecal delivery of HGF would have an impact on one of the most common pathologies of ALS: the TDP-43 pathology. Increased astrogliosis, microgliosis and progressive upper motor neuron loss are important consequences of ALS in the motor cortex with TDP-43 pathology. We find that cortex can be modulated via intrathecal injection, and that expression of HGF reduces astrogliosis, microgliosis in the motor cortex, and help restore ongoing UMN degeneration. Our findings not only introduce a novel viral vector for the treatment of ALS, but also demonstrate modulation of motor cortex by intrathecal viral delivery, and that HGF treatment is effective in reducing astrogliosis and microgliosis in the motor cortex of ALS with TDP-43 pathology.

Lentivirus-Mediated VEGF Knockdown Suppresses Gastric Cancer Cell Proliferation and Tumor Growth in vitro and in vivo.

PURPOSE: Gastric cancer has a high mortality rate worldwide. Although treatments, such as molecular-targeted therapy, have been introduced, the resulting long-term survival and prognosis remain unsatisfactory. Downregulation of the target genes using lentivirus-mediated short hairpin RNA (shRNA) can be an effective therapeutic strategy for patients with gastric cancer. Overexpressed vascular endothelial growth factor A (VEGF) in human gastric cancer cells can be an effective novel therapeutic target for human gastric cancer. Thus, this study aimed to evaluate the therapeutic effects of lentivirus-mediated knockdown of VEGF gene expression in human gastric cancer growth. MATERIALS AND METHODS: Specific shRNA sequences targeting VEGF were designed to construct a lentiviral expression vector. After human gastric carcinoma cells (cell line NCI-N87) were infected with the lentiviral vector, the therapeutic effects of the lentivirus-mediated shRNA targeting VEGF were analyzed both in vitro and in vivo. RESULTS: Stable suppression of VEGF gene expression in NCI-N87 cells using shRNA (ShVEGF) showed significant inhibition of cell proliferation, clonogenicity, and cell motility. ShVEGF also showed increased G0/G1 cell cycle arrest and apoptosis. In addition, in vivo results from nude mice xenografted ShVEGF showed significant inhibition of tumor growth. Assessing the therapeutic effects of intratumoral injection of lentivirus-targeting VEGF (Virus_VEGF) revealed that it significantly inhibited tumor growth compared to that in the Virus_Scramble or saline injection control groups. CONCLUSION: The constructed ShVEGF showed significant inhibition of NCI-N87 gastric cancer cell growth both in vitro and in vivo. These experimental results suggest a novel therapeutic strategy for patients with gastric cancer using lentivirus-mediated shRNA targeting VEGF.

Radioprotective effect of newly synthesized toll-like receptor 5 agonist, KMRC011, in mice exposed to total-body irradiation.

Exposure to ionizing radiation leads to severe damages in radiosensitive organs and induces acute radiation syndrome, including effects on the hematopoietic system and gastrointestinal system. In this study, the radioprotective ability of KMRC011, a novel toll-like receptor 5 (TLR5) agonist, was investigated in C57BL6/N mice exposed to lethal total-body gamma-irradiation. In a 30-day survival study, KMRC011-treated mice had a significantly improved survival rate compared with control after 11 Gy total-body irradiation (TBI), and it was found that the radioprotective activity of KMRC011 depended on its dosage and repeated treatment. In a 5-day short-term study, we demonstrated that KMRC011 treatment stimulated cell proliferation and had an anti-apoptotic effect. Furthermore, KMRC011 increased the expressions of genes related to DNA repair, such as Rad21, Gadd45b, Sod2 and Irg1, in the small intestine of lethally irradiated mice. Interestingly, downregulation of NF-κB p65 in the mouse intestine by KMRC011 treatment was observed. This data indicated that KMRC011 exerted a radioprotective activity partially by regulating NF-κB signaling. Finally, peak expression levels of G-CSF, IL-6, IFN-γ, TNF-α and IP-10 induced by KMRC011 treatment were different depending on the route of administration and type of cytokine. These cytokines could be used as candidate biomarkers for the evaluation of KMRC011 clinical efficacy. Our data indicated that KMRC011 has radioprotective activity in lethally irradiated mice and may be developed as a therapeutic agent for radioprotection.

A murine colitis model developed using a combination of dextran sulfate sodium and Citrobacter rodentium.

Adult mice were treated with dextran sulfate sodium (DSS) and infected with Citrobacter rodentium for developing a novel murine colitis model. C57BL/6N mice (7-week-old) were divided into four groups. Each group composed of control, dextran sodium sulfate-treated (DSS), C. rodentium-infected (CT), and DSS-treated and C. rodentium-infected (DSS-CT) mice. The DSS group was administered 1% DSS in drinking water for 7 days. The CT group was supplied with normal drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The DSS-CT group was supplied with 1% DSS in drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The mice were sacrificed 10 days after the induction of C. rodentium infection. The DSS-CT group displayed significantly shorter colon length, higher spleen to body weight ratio, and higher histopathological score compared to the other three groups. The mRNA expression levels of tumor necrosis factor (TNF)-α and interferon (INF)-γ were significantly upregulated; however, those of interleukin (IL)-6 and IL-10 were significantly downregulated in the DSS-CT group than in the control group. These results demonstrated that a combination of low DSS concentration (1%) and C. rodentium infection could effectively induce inflammatory bowel disease (IBD) in mice. This may potentially be used as a novel IBD model, in which colitis is induced in mice by the combination of a chemical and a pathogen.

Gradient-echo-based 3D submillisecond echo time pulmonary MR imaging: a preliminary usability study on clinical and preclinical MR scanners.

OBJECTIVE: To preliminarily investigate a technical feasibility of a submillisecond echo time concurrent-dephasing-and-excitation (CODE) sequence for pulmonary MRI on clinical and preclinical MR scanners Methods: CODE imaging (echo time, 0.14 ~ 0.18 ms) was performed with American College of Radiology phantom at 3 T, 7 healthy volunteers at 1.5 and 3 T, 10 rabbits at 3 T, and 2 rodents at 9.4 T. Signal-to-noise ratio was compared in phantom. Image quality of human MRI was visually assessed on a 5-point scale for comparison between CODE and conventional lung MRI sequences. Visibility of bronchi, subcentimeter nodules, and MR air-bronchogram were assessed in animal studies. RESULTS: In phantom study, signal-to-noise ratio was higher with CODE than with original three-dimensional ultrashort-echo time sequence (106.71 ± 4.32 vs 91.66 ± 3.54; p < 0.001). Image quality of human MRI was better with CODE than with conventional MRI sequences (p ≤ 0.002). Bronchi remained traceable up to the fifth bronchial generation in CODE images in rabbits and rodents. 95.2% of metastatic nodules (diameter, 1.5 ± 0.4 mm) and 93.8% of MR air-bronchogram (diameter, 0.9 ± 0.2 mm) in rabbits. CONCLUSION: Submillisecond echo time pulmonary MRI was technically feasible by using CODE on various MR scanners. Advances in knowledge: CODE can be a practical alternative for lung MRI on both clinical and pre-clinical scanners, without challenges of free-induction-decay-based ultrashort-echo time sequences.

In-vivo Visualization of Iron Oxide Enhancement in Focal Pulmonary Inflammatory Lesions Using a Three-Dimensional Radial Gradient-Echo-Based Ultrashort Echo Time Sequence: A Preliminary Study.

Objective: To preliminarily evaluate technical feasibility of a dual-echo ultrashort echo time (UTE) subtraction MR imaging by using concurrent dephasing and excitation (CODE) sequence for visualization of iron-oxide enhancement in focal inflammatory pulmonary lesions. Materials and Methods: A UTE pulmonary MR imaging before and after the injection of clinically usable superparamagnetic iron-oxide nanoparticles, ferumoxytol, was conducted using CODE sequence with dual echo times of 0.14 ms for the first echo and 4.15 ms for the second echo on 3T scanner in two rabbits concurrently having granulomatous lung disease and lung cancer in separate lobes. A mean ratio of standardized signal intensity (SI) was calculated for comparison of granulomatous lesion and cancer at first echo, second echo, and subtracted images. Lesions were pathologically evaluated with Prussian blue and immunohistochemistry staining. Results: Post-contrast subtracted CODE images visualized exclusive enhancement of iron oxide in granulomatous disease, but not in the cancer (mean ratio of SI, 2.15 ± 0.68 for granulomatous lesion versus 1.00 ± 0.07 for cancer; p value = 0.002). Prussian blue and corresponding anti-rabbit macrophage IgG-staining suggested an intracellular uptake of iron-oxide nanoparticles in macrophages of granulomatous lesions. Conclusion: Dual-echo UTE subtraction MR imaging using CODE sequence depicts an exclusive positive enhancement of iron-oxide nanoparticle in rabbits in focal granulomatous inflammatory lesions.

Establishment of a mouse model of 70% lethal dose by total-body irradiation.

Whereas increasing concerns about radiation exposure to nuclear disasters or side effects of anticancer radiotherapy, relatively little research for radiation damages or remedy has been done. The purpose of this study was to establish level of LD70/30 (a lethal dose for 70% of mice within 30 days) by total-body γ irradiation (TBI) in a mouse model. For this purpose, at first, 8-week-old male ICR and C57BL/6N mice from A and B companies were received high dose (10, 11, 12 Gy) TBI. After irradiation, the body weight and survival rate were monitored for 30 days consecutively. In next experiment, 5-week-old male ICR and C57BL/6N mice from B company were received same dose irradiation. Results showed that survival rate and body weight change rate in inbred C57BL/6N mice were similar between A and B company. In ICR mice, however, survival rate and body weight change rate were completely different among the companies. Significant difference of survival rate both ICR and C57BL6N mice was not observed in between 5-week-old and 8-week-old groups receiving 10 or 12 Gy TBI. Our results indicate that the strain and age of mice, and even purchasing company (especially outbred), should be matched over experimental groups in TBI experiment. Based on our results, 8-week-old male ICR mice from B company subjected to 12 Gy of TBI showed LD70/30 and suitable as a mouse model for further development of new drug using the ideal total-body irradiation model.

The Probiotic Lactobacillus Prevents Citrobacter rodentium-Induced Murine Colitis in a TLR2-Dependent Manner.

The main objective of this study was to investigate whether Lactobacillus rhamnosus GG (LGG) ameliorated the effects of Citrobactor rodentium infection in Toll-like receptor 2 (TLR2) knockout (KO) and TLR4 KO mice, as well as in wild-type C57BL/6 (B6) mice. TLR2 KO, TLR4 KO, and B6 mice were divided into three groups per each strain. Each group had an uninfected control group (n = 5), C. rodentium-infected group (n = 8), and LGG-pretreated C. rodentium-infected group (n = 8). The survival rate of B6 mice infected with C. rodentium was higher when pretreated with LGG. Pretreatment with LGG ameliorated C. rodentium-induced mucosal hyperplasia in B6 and TLR4 KO mice. However, in C-rodentium-infected TLR2 KO mice, mucosal hyperplasia persisted, regardless of pretreatment with LGG. In addition, LGG-pretreated B6 and TLR4 KO mice showed a decrease in spleen weight and downregulation of tumor necrosis factor alpha, interferon gamma, and monocyte chemotactic protein 1 mRNA expression compared with the non-pretreated group. In contrast, such changes were not observed in TLR2 KO mice, regardless of pretreatment with LGG. From the above results, we conclude that pretreatment with LGG ameliorates C. rodentium-induced colitis in B6 and TLR4 KO mice, but not in TLR2 KO mice. Therefore, LGG protects mice from C. rodentium-induced colitis in a TLR2-dependent manner.

Anti-inflammatory effects of magnolol and honokiol are mediated through inhibition of the downstream pathway of MEKK-1 in NF-kappaB activation signaling.

Propionibacterium acnes, an anaerobic pathogen, plays an important role in the pathogenesis of acne and seems to initiate the inflammatory process by producing proinflammatory cytokines. In order to demonstrate the anti-inflammatory effects and action mechanisms of magnolol and honokiol, several methods were employed. Through DPPH and SOD activity assays, we found that although both magnolol and honokiol have antioxidant activities, honokiol has relatively stronger antioxidant activities than magnolol {[for DPPH assay, % of DPPH bleaching of magnolol and honokiol (500 microM magnolol: 19.8%; 500 microM honokiol: 67.3%)]; [for SOD assay, SOD activity (200 microM magnolol: 53.4%; 200 microM honokiol: 64.3%)]}. Moreover, the production of interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) induced by P. acnes in THP-1 cells, a human monocytic cell line, was reduced by magnolol and honokiol {[for IL-8 (10 microM magnolol: 42.7% inhibition; 10 microM honokiol: 51.4% inhibition)]; [for TNF-alpha (10 microM magnolol: 20.3% inhibition; 10 microM honokiol: 39.0% inhibition)]}. Cyclooxygenase-2 (Cox-2) activity was also suppressed by them [(15 microM magnolol: 45.8% inhibition), (15 microM honokiol: 66.3% inhibition)]. Using a nuclear factor-kappaB (NF-kappaB) luciferase reporter assay system and Western analysis, we identified that magnolol and honokiol exert their anti-inflammatory effects by inhibiting the NF-kappaB element, which exists in Cox-2, IL-8, and TNF-alpha promoters [(15 microM magnolol: 44.8% inhibition), (15 microM honokiol: 42.3% inhibition)]. Of particular note is that magnolol and honokiol operate downstream of the MEKK-1 molecule. Together with their previously known antibacterial activity against P. acnes and based on these results, we suggest that magnolol and honokiol may be introduced as possible acne-mitigating agents.

Glycyrrhizin induces melanogenesis by elevating a cAMP level in b16 melanoma cells.

In mammalian melanocytes, melanin synthesis is controlled by tyrosinase, the critical enzyme in the melanogenic pathway. A recent report showed that the stimulation of melanogenesis by glycyrrhizin (GR) is because of an increased tyrosinase expression at mRNA and protein levels. But, the molecular events of melanogenesis induced by GR remain to be elucidated. In this study, using B16 melanoma cells, we showed that GR activated activator protein-1 (AP-1) and cyclic response filament "CRE" promoters, but not the nuclear factor-kappaB promoter. In addition, although GR stimulated mitogen-activated protein (MAP) kinase, p42/44(mapk), consistent with GR-induced AP-1 promoter activation, GR-induced melanogenesis was not blocked by PD98059, an MEK1 inhibitor, suggesting that MAPkinase induced by GR does not have a direct effect on the level of melanin content. But, GR-induced melanogenesis was inhibited by an inhibitor of protein kinase A (H-89). This result was further confirmed by the fact that GR induced the phosphorylation of CRE binding protein (CREB) and inhibition of glycogen synthase kinase 3beta phosphorylation as well as the production of cAMP, indicating that GR induces melanogenesis through cAMP signaling. In addition, the fact that GR-induced CRE activation was blocked by H-89 but GR-induced increase of cAMP production was not suggests that GR operates upstream of protein kinase A.