Jiwoong Kwon

Direct decompressive surgery followed by radiotherapy versus radiotherapy alone for metastatic epidural spinal cord compression: a meta-analysis.

Study Design. A systemic review and meta-analysis. Objective. To compare the ambulatory status and survival for metastatic epidural spinal cord compression (MESCC) in patients treated with direct decompressive surgical resection (DDSR) followed by radiotherapy (RTx) with those in patients treated with RTx alone. Summary of Background Data. Surgical techniques have remarkably evolved from decompressive laminectomy without ventral tumor excision to DDSR, which has displayed favorable outcomes since the 2000s. RTx alone has also evolved and is regarded to have accomplished outcome comparable with that of the surgery. The optimal treatment of MESCC has not been clearly defined yet. Methods. We searched MEDLINE, EMBASE, and the Cochrane library in July 2013. Comparative studies enrolled patients with similar performance, primary cancer, age, and sex at the baseline state were included. Outcome measures included ambulatory status and overall survival rate. We did a fixed-effects meta-analysis of the ambulatory status and survival in patients with MESCC compared with DDSR+RTx and RTx alone. Results. Five studies were used to obtain data from 238 and 1137 patients treated with DDSR+RTx and RTx alone, respectively. The DDSR+RTx group displayed substantial improvement in ambulatory status after the treatment that was superior to the improvement in the RTx-alone group (relative risk [RR], 1.43; 95% confidence interval [CI], 1.14–1.78) in a fixed-effects model and significantly lower deterioration after treatment than the RTx group (RR, 0.35; 95% CI, 0.19–0.63). The DDSR+RTx group showed significant improvement in the survival rate at 6 months post-treatment (RR, 1.21; 95% CI, 1.09–1.33). Similar findings were observed at 12 months post-treatment (RR, 1.32; 95% CI, 1.12–1.56). Conclusion. The meta-analysis indicates that DDSR+RTx may produce better clinical improvement of ambulation status and survival than RTx alone in the treatment of MESCC. Additional prospective studies are warranted to better address this question. Level of Evidence: 1

RESOLFT nanoscopy with photoswitchable organic fluorophores.

Far-field optical nanoscopy has been widely used to image small objects with sub-diffraction-limit spatial resolution. Particularly, reversible saturable optical fluorescence transition (RESOLFT) nanoscopy with photoswitchable fluorescent proteins is a powerful method for super-resolution imaging of living cells with low light intensity. Here we demonstrate for the first time the implementation of RESOLFT nanoscopy for a biological system using organic fluorophores, which are smaller in size and easier to be chemically modified. With a covalently-linked dye pair of Cy3 and Alexa647 to label subcellular structures in fixed cells and by optimizing the imaging buffer and optical parameters, our RESOLFT nanoscopy achieved a spatial resolution of ~74 nm in the focal plane. This method provides a powerful alternative for low light intensity RESOLFT nanoscopy, which enables biological imaging with small organic probes at nanoscale resolution.

Pyogenic Vertebral Osteomyelitis: Clinical Features, Diagnosis, and Treatment

Pyogenic vertebral osteomyelitis (PVO) may result in neurological deficits and sequelae, so early diagnosis and appropriate treatment are critical. Many previous studies on PVO exist, but our paper has aimed to comprehensively summarize the clinical aspects of PVO. Through review of the vast literature on the clinical research of PVO an overview of the clinical characteristics, diagnostic methods, treatment and prognosis is provided.

New sub-diffraction-limit microscopy technique: dual-point illumination AND-gate microscopy on nanodiamonds (DIAMOND).

We introduce a new, easily implementable sub-diffraction-limit microscopy technique utilizing the optical AND-gate property of fluorescent nanodiamond (FND). We demonstrate that when FND is illuminated by two spatially-offset lights of different wavelengths, emission comes only from the region of their overlap, which is used to reduce the effective point spread function from ~300 nm to ~130 nm in lateral plane, well below the diffraction limit.

Health Care Burden of Spinal Diseases in the Republic of Korea: Analysis of a Nationwide Database From 2012 Through 2016

Objective This study aimed to determine the incidence and analyze trends related to spinal diseases based on a national database in the Republic of Korea (ROK) and to elucidate the healthcare burden that will serve as a useful resource for researchers, clinicians, and patients. Methods This study was a retrospective analysis of data obtained from Healthcare Bigdata Hub, the Korean Statistical Information Service, and Open Data Portal from 2012 through 2016. The main disease codes for spinal diseases (M40–M54) were used for identification of these conditions. Results The overall annual incidence rates for spinal disease in the ROK was median 15,877 (men, 13,181; women, 18,588) per 100,000 population, and sex ratio was 1:1.41 (p<0.01). The incidence rate and annual costs per patient increased by 7.6% and 14.7% over 5 years continuously, respectively. The age-adjusted incidence rate increased with age; the highest rates were 42.6% in the 75–79 years group. Patients older than 65 years old accounted for median 31.0% of number of patients and 40.1% of medical expenses over 5 years. Lumbar disc herniation (M51) and spinal stenosis (M48) might accounted for both the highest incidence and medical expenses in patients under the age of 60 and over 60 years, respectively. Conclusion The incidence and medical expenditures of spinal disease increased continuously. As the population of ROK in aging, the incidence and medical expenditures due to spondylosis and stenosis (M48) for the old are also increasing. The social burden of spinal diseases in elder patients needs to be prudently considered in health policy makers.

Leucine-induced localization of Leucyl-tRNA synthetase in lysosome membrane

Leucyl-tRNA synthetase (LRS) plays major roles in providing leucine-tRNA and activating mechanistic target of rapamycin complex 1 (mTORC1) through intracellular leucine sensing. mTORC1 activated by amino acids affects the influence on physiology functions including cell proliferation, protein synthesis and autophagy in various organisms. Biochemical results demonstrating leucine sensing have been published, but visual results are lacking. Therefore, we observed the location of LRS with and without leucine using stimulated emission depletion (STED) microscopy one of the super-resolution microscopy and transmission electron microscopy (TEM). This revealed that LRS was translocated to the lysosome on addition of leucine. The translocation was inhibited by treatment with compound BC-LI-0186, disrupting the interaction between RagD and LRS. Immuno-TEM revealed a clear decrease in LRS translocation to the lysosome on addition of the inhibitor. This direct visualization of leucine sensing and LRS translocation to the lysosome was related to mTORC1 activation. To study the relationship between mTORC1 activation and LRS translocation, we monitored the change in autophagy for each condition using TEM and CLSM. The results showed a decrease in autophagy on addition of leucine, demonstrating crosstalk between leucine sensing, LRS translocation, RagD interaction, and mTORC1 activation.

Possible electric field induced indirect to direct band gap transition in MoSe 2

Direct band-gap semiconductors play the central role in optoelectronics. In this regard, monolayer (ML) MX2 (M = Mo, W; X = S, Se) has drawn increasing attention due to its novel optoelectronic properties stemming from the direct band-gap and valley degeneracy. Unfortunately, the more practically usable bulk and multilayer MX2 have indirect-gaps. It is thus highly desired to turn bulk and multilayer MX2 into direct band-gap semiconductors by controlling external parameters. Here, we report angle-resolved photoemission spectroscopy (ARPES) results from Rb dosed MoSe2 that suggest possibility for electric field induced indirect to direct band-gap transition in bulk MoSe2. The Rb concentration dependent data show detailed evolution of the band-gap, approaching a direct band-gap state. As ionized Rb layer on the surface provides a strong electric field perpendicular to the surface within a few surface layers of MoSe2, our data suggest that direct band-gap in MoSe2 can be achieved if a strong electric field is applied, which is a step towards optoelectronic application of bulk materials.