2,322 research outputs found
Retraction: Cortical Margining Capabilities of Fins Associated with Ventral Cervical Spine Instrumentation
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Fortnightly variability of horizontal salinity gradient affects exchange flow in the Sumjin River estuary
The horizontal salinity gradient has been reported to play a crucial role in fortnightly variability of estuarine exchange flow in short estuaries. However, spatiotemporal variations in the salinity gradient and exchange flow have not been examined over an entire short estuary, as only data observed only at specific points was available. We analyzed the variation in salinity gradient along the entire Sumjin River estuary and its effect on the exchange flow over fortnightly tidal cycles based on observations and numerical model experiments. The salinity gradient and exchange flow were in different phases between the lower and upper estuaries by 6–7 days. The maximum salinity gradient periodically reciprocated along the channel as a result of salt flux changes determined by vertical mixing. The stronger exchange flow (> 0.04 m s-1) changed location from mouth to head of estuary while the tidal range decreased, resulting from variability of the salinity gradient. The horizontal salinity gradient is large enough to overwhelm the vertical mixing effect on the exchange flow. The spatiotemporal changes of strong exchange flow correspond well with the horizontal Richardson number value (> 3). This study suggests that for the health of estuarine ecosystems, it is important to determine the spatiotemporal variation in exchange flow throughout the estuary
Carotid Endarterectomy for Symptomatic Complete Occlusion of the Internal Carotid Artery
We described 9 consecutive patients who underwent operative carotid artery exploration with attempted carotid endarterectomy (CEA) for symptomatic internal carotid artery (ICA) occlusion. Indications for this surgery based on vascular imaging included segmental occlusion of the proximal ICA and also extensive occlusion of the distal ICA in selected patients in whom color-flow duplex ultrasound showed a poorly echogenic or anechoic thrombus with a flow void, suggestive of an acute thrombus. CEA was performed successfully to restore blood flow in all 9 patients:CEA in 5 and CEA with Fogarty thrombectomy in 4. Postoperative magnetic resonance (MR) angiography confirmed that revascularization had been successful in all 9 patients, and MR imaging displayed improved perfusion in 4 patients. Despite the lack of a generalized efficacy of surgical revascularization for symptomatic ICA occlusion, our study demonstrated that preoperative vascular imaging allows the selection of patients who may benefit from CEA
Time-resolved pathogenic gene expression analysis of the plant pathogen Xanthomonas oryzae pv. oryzae
Virulence of wild-type and mutant Xoo strains on rice. (DOCX 16Â kb
Superparamagnetic Iron Oxide Nanoparticles Coated with Galactose-Carrying Polymer for Hepatocyte Targeting
Our goal is to develop the functionalized superparamagnetic
iron oxide nanoparticles (SPIONs) demonstrating the capacities
to be delivered in liver specifically and to be dispersed in
physiological environment stably. For this purpose, SPIONs
were coated with polyvinylbenzyl-O-β-D-galactopyranosyl-D-gluconamide (PVLA) having
galactose moieties to be recognized by asialoglycoprotein
receptors (ASGP-R) on hepatocytes. For use as a control, we also
prepared SPIONs coordinated with 2-pyrrolidone. The sizes, size
distribution, structure, and coating of the nanoparticles were
characterized by transmission electron microscopy (TEM),
electrophoretic light scattering spectrophotometer (ELS), X-ray
diffractometer (XRD), and Fourier transform infrared (FT-IR),
respectively. Intracellular uptake of the PVLA-coated SPIONs was
visualized by confocal laser scanning microscopy, and their
hepatocyte-specific delivery was also investigated through
magnetic resonance (MR) images of rat liver. MRI experimental
results indicated that the PVLA-coated SPIONs possess the more
specific accumulation property in liver compared with control,
which suggests their potential utility as liver-targeting MRI
contrast agent
Trichosanthes kirilowii
Trichosanthes kirilowii tuber is a traditional medicine which exhibits various medicinal effects including antidiabetic and anticancer activities in several cancer cells. Recently, it was reported that Cucurbitacin D (CuD) isolated from Trichosanthes kirilowii also induces apoptosis in several cancer cells. Constitutive signal transducer and activator of transcription 3 (STAT3), which is an oncogenic transcription factor, is often observed in many human malignant tumor, including breast cancer. In the present study, we tested whether Trichosanthes kirilowii ethanol extract (TKE) or CuD suppresses cell growth and induces apoptosis through inhibition of STAT3 activity in breast cancer cells. We found that both TKE and CuD suppressed proliferation and induced apoptosis and G2/M cell cycle arrest in MDA-MB-231 breast cancer cells by inhibiting STAT3 phosphorylation. In addition, both TKE and CuD inhibited nuclear translocation and transcriptional activity of STAT3. Taken together, our results indicate that TKE and its derived compound, CuD, could be potent therapeutic agents for breast cancer, blocking tumor cell proliferation and inducing apoptosis through suppression of STAT3 activity
cAMP signaling inhibits radiation-induced ATM phosphorylation leading to the augmentation of apoptosis in human lung cancer cells
Background: The ataxia–telangiectasia mutated (ATM) protein kinase plays a central role in coordinating the cellular response to radiation-induced DNA damage. cAMP signaling regulates various cellular responses including metabolism and gene expression. This study aimed to investigate the mechanism through which cAMP signaling regulates ATM activation and cellular responses to ionizing radiation in lung cancer cells.
Methods: Lung cancer cells were transfected with constitutively active stimulatory G protein (GαsQL), and irradiated with γ-rays. The phosphorylation of ATM and protein phosphatase 2A was analyzed by western blotting, and apoptosis was assessed by western blotting, flow cytometry, and TUNNEL staining. The promoter activity of NF-κB was determined by dual luciferase reporter assay. BALB/c mice were treated with forskolin to assess the effect in the lung tissue.
Results: Transient expression of GαsQL significantly inhibited radiation-induced ATM phosphorylation in H1299 human lung cancer cells. Treatment with okadaic acid or knock down of PP2A B56δ subunit abolished the
inhibitory effect of Gαs on radiation-induced ATM phosphorylation. Expression of GαsQL increased phosphorylation of the B56δ and PP2A activity, and inhibition of PKA blocked Gαs-induced PP2A activation. GαsQL enhanced radiation-induced cleavage of caspase-3 and PARP and increased the number of early apoptotic cells. The radiation-induced apoptosis was increased by inhibition of NF-κB using PDTC or inhibition of ATM using KU55933 or siRNA against ATM. Pretreatment of BALB/c mice with forskolin stimulated phosphorylation of PP2A B56δ,
inhibited the activation of ATM and NF-κB, and augmented radiation-induced apoptosis in the lung tissue. GαsQL
expression decreased the nuclear levels of the p50 and p65 subunits and NF-κB-dependent activity after γ-ray
irradiation in H1299 cells. Pretreatment with prostaglandin E2 or isoproterenol increased B56δ phosphorylation,
decreased radiation-induced ATM phosphorylation and increased apoptosis.
Conclusions: cAMP signaling inhibits radiation-induced ATM activation by PKA-dependent activation of PP2A, and this signaling mechanism augments radiation-induced apoptosis by reducing ATM-dependent activation of NF-κB in lung cancer cells.This study was supported by a National Research Foundation (NRF) grant funded by the Korea government (MEST) (No. 2007–2001258), by Basic Science Research Program through the NRF funded by the Ministry of Education, Science and Technology (2012R1A1A2044374), and a grant from the National R&D Program for Cancer Control, Ministry of Health and Welfare, Republic of Korea (0720540).Peer Reviewe
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