During early viral infection, activation of natural killer (NK) cells elicits the effector functions of target cell lysis and cytokine production. However, the cellular and molecular mechanisms ...leading to NK cell activation during viral infections are incompletely understood. In this study, using a model of acute viral infection, we investigated the mechanisms controlling cytotoxic activity and cytokine production in response to influenza (flu) virus. Analysis of cytokine receptor deficient mice demonstrated that type I interferons (IFNs), but not IL-12 or IL-18, were critical for the NK cell expression of both IFN-γ and granzyme B in response to flu infection. Further, adoptive transfer experiments revealed that NK cell activation was mediated by type I IFNs acting directly on NK cells. Analysis of signal transduction molecules showed that during flu infection, STAT1 activation in NK cells was completely dependent on direct type I IFN signaling, whereas STAT4 activation was only partially dependent. In addition, granzyme B induction in NK cells was mediated by signaling primarily through STAT1, but not STAT4, while IFN-γ production was mediated by signaling through STAT4, but not STAT1. Therefore, our findings demonstrate the importance of direct action of type I IFNs on NK cells to mount effective NK cell responses in the context of flu infection and delineate NK cell signaling pathways responsible for controlling cytotoxic activity and cytokine production.
Retrospective comparative study.
To investigate the consequences and appropriate management of pseudarthrosis after anterior cervical discectomy and fusion (ACDF).
Pseudarthrosis is a frequent ...complication of ACDF and causes unsatisfactory results. Little is known about long-term prognosis of detecting pseudarthrosis 1 year after ACDF.
Eighty-nine patients with a minimum 2-year follow-up were included. ACDF surgery using allograft and plating was performed: single-level in 51 patients, two-level in 26 patients, and three-level in 12 patients. Presence of pseudarthrosis was evaluated 1 year postoperatively and then the nonunion segments were re-evaluated 2 years postoperatively. Demographic data were assessed to identify the risk factors associated with pseudarthrosis. A visual analogue scale for neck/arm pain and the Neck Disability Index were analyzed preoperatively and at 1 and 2 years postoperatively.
Pseudarthrosis was detected in 29 patients (32.6%) 1 year postoperatively: 15of 51 patients after single-level surgery, 9 of 26 patients after two-level surgery, and 5 of 12 patients after three-level surgery. Only eight patients showed persistent nonunion at 2 years: 3 of 15 patients after single-level surgery, 3 of 9 after two-level surgery, and 2 of 5 after three-level surgery. The remaining 21 patients (72.4%) achieved bony fusion 2 years postoperatively without any intervention. Patients who underwent two-level or three-level ACDF had a significantly higher pseudarthrosis rate than those who underwent single-level ACDF, with odds ratios of 1.844 and 3.147, respectively. The improvements in visual analogue scale for neck pain and Neck Disability Index scores in the persistent nonunion group were significantly lower than those in the final union group at 2 years.
Patients with pseudarthrosis detected 1 year postoperatively may be observed without any intervention because approximately 70% of them will eventually fuse by the 2-year point. Early revision could, however, be considered if the pseudarthrosis is associated with considerable neck pain after multilevel ACDF.
3.
Abstract
This study aimed to evaluate the subclinical gait abnormalities and the postoperative gait improvements in patients with degenerative cervical myelopathy using three-dimensional gait ...analysis. We reviewed the gait analysis of 62 patients who underwent surgical treatment for degenerative cervical myelopathy. The asymptomatic gait group included 30 patients and the gait disturbance group included 32 patients who can walk on their own slowly or need assistive device on stairs. The step width (17.2 cm vs. 15.9 cm,
P
= 0.003), stride length (105.2 cm vs. 109.1 cm,
P
= 0.015), and double-limb support duration (13.4% vs. 11.7%,
P
= 0.027) improved only in the asymptomatic gait group. Preoperatively, the asymptomatic gait group exhibited better maximum knee flexion angle (60.5° vs. 54.8°,
P
= 0.001) and ankle plantarflexion angle at push-off (− 12.2° vs. − 6.5°,
P
= 0.001) compared to the gait disturbance group. Postoperatively, maximum knee flexion angle (62.3° vs. 58.2°,
P
= 0.004) and ankle plantarflexion angle at push-off (− 12.8° vs. − 8.3°,
P
= 0.002) were still better in the asymptomatic gait group, although both parameters improved in the gait disturbance group (
P
= 0.005, 0.039, respectively). Kinematic parameters could improve in patients with gait disturbance. However, temporospatial parameters improvement may be expected when the operative treatment is performed before apparent gait disturbance.
Conventional laminoplasty is useful for expanding a stenotic spinal canal. However, it has limited use for the decompression of accompanying neural foraminal stenosis. As such, an additional ...posterior foraminotomy could be simultaneously applied, although this procedure carries a risk of segmental kyphosis and instability.
The aim of this study was to elucidate the long-term surgical outcomes of additional posterior foraminotomy with laminoplasty (LF) for cervical spondylotic myelopathy (CSM) with radiculopathy.
A retrospective comparative study was carried out.
Ninety-eight consecutive patients who underwent laminoplasty for CSM with radiculopathy between January 2006 and December 2012 were screened for eligibility. This study included 66 patients, who were treated with a laminoplasty of two or more levels and followed up for more than 2 years after surgery.
The Neck Disability Index (NDI), Japanese Orthopedic Association (JOA) scores, JOA recovery rates, and visual analog scale (VAS) were used to evaluate clinical outcomes. The C2–C7 sagittal vertical axis distance, cervical lordosis, range of motion (ROM), and angulation and vertebral slippage at the foraminotomy level were used to measure radiological outcomes using the whole spine anterioposterior or lateral and dynamic lateral radiographs.
Sixty-six patients with CSM with radiculopathy involving two or more levels were consecutively treated with laminoplasty and followed up for more than 2 years after surgery. The first 26 patients underwent laminoplasty alone (LA group), whereas the next 40 patients underwent an additional posterior foraminotomy at stenotic neural foramens with radiating symptoms in addition to laminoplasty (LF group). In the LF group, the foraminotomy with less resection than 50% of facet joint to avoid segmental kyphosis and instability was performed at 78 segments (unilateral-to-bilateral ratio=57:21) and 99 sites. Clinical and radiographic data were assessed preoperatively and at 2-year follow-up and compared between the groups.
The NDI, JOA scores, JOA recovery rates, and VAS for neck and arm pain were improved significantly in both groups after surgery. The improvement in the VAS for arm pain was significantly greater in the LF group (from 5.55±2.52 to 1.85±2.39) than the LA group (from 5.48±2.42 to 3.40±2.68) (p<.001). Although cervical lordosis and ROM decreased postoperatively in both groups, there were no significant differences in the degree of reduction between the LF and LA groups. Although the postoperative focal angulation and slippage were slightly increased in the LF group, this was not to a significant degree. Furthermore, segmental kyphosis and instability were not observed in the LF group, regardless of whether the patient underwent a unilateral or bilateral foraminotomy.
Additional posterior foraminotomy with laminoplasty is likely to improve arm pain more significantly than laminoplasty alone by decompressing nerve roots. Also, performing posterior foraminotomy via multiple levels or bilaterally did not significantly affect segmental malalignment and instability. Therefore, when a laminoplasty is performed for CSM with radiculopathy, an additional posterior foraminotomy could be an efficient and safe treatment that improves both myelopathy symptoms and radicular arm pain.
Bench- and pilot-scale membrane tests were performed to remove natural organic matter (NOM) originating from Paldang Lake in Korea. Membrane performance was demonstrated in terms of DOC, ...biodegradable organic carbon (BDOC), assimilable organic carbon (AOC), and transport parameters. Various membranes such as reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) were investigated for this study. Four different NF membranes were selected for pilot-scale filtration testing and investigated in terms of both flux decline and DOC removal. To demonstrate the effect of temperature on the source water seasonally, the flux of membranes was measured with pure water at different temperatures ranging from 25 to 7°C. Coagulation/sedimentation treated water was used as feed water without removing residual chlorine; related plants were located at the Suji water treatment plant of Yongin City. To investigate more rigorously the organic fouling for various NF membranes, mass transport behaviors of organic matter solutes were evaluated by an irreversible thermodynamic model. The pore sizes of the NF membranes tested in the pilot slightly increased due to the oxidation of the polymer structure of the membranes from residual chlorine during the 4-month tests. Periodic chemical cleaning with a caustic solution was made to prevent accumulation of foulants on the membrane surface. The NF membranes exhibited stable efficiencies in terms of DOC and AOC removal during the test for 4 months.
Recently rise in oil prices feet the burden on not only diesel vehicle driver but also LPG vehicle driver, and get interested in various way to reduce fuel costs. In this study discuss on exhaust ...emissions characteristics on driving cycle mode and ignition advance condition change of CNG/LPLI Bi-Fuel vehicle. Experimental test was performed by changing the conditions of fuel (LPG/CNG), spark advance (Base, 10oCA, 15oCA), and driving mode (FTP-75, HWFET, and NEDC). In case of CO emission, in the order of CNG Base, CNG S/A10, S/A15 condition are average reduced -21%, -35%, -29% respectively compared to LPG fuel. The active emission reduction from the initial engine start, spark retard is likely to be beneficial in catalyst warm-up and improve combustion stability rather than spark advance.
Due to persist of high oil prices, LPG price stabilization and CNG modification project will be conducted. Present study describes the fuel efficiency and $CO_2$ emission characteristics on driving ...cycle mode and ignition advance condition change of CNG/LPG Bi-Fuel vehicle. In case of LPG Base and CNG Base condition, considerable $CO_2$ emissions are generated within range of high acceleration on FTP-75 and HWFET driving mode. However previous phenomena does not appear in CNG fuel $10^{\circ}CA$ and $15^{\circ}CA$ spark advance condition. As a result of analyzing the experimental data CNG $S/A10^{\circ}CA$, CNG $S/A15^{\circ}CA$, CNG Base, and LPG Base sequentially measured high fuel economy and low $CO_2$ emission characteristics.
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