A Neurostimulator Design for Long-term Animal Experiments

This article reports on a neural prosthesis stimulation system for long-term use in animal electrical stimulation experiments. The presented system consists of an implantable stimulator which provides continuous electrical stimulation, and an external component which provides preset stimulation parameters and power to the implanted stimulator via a paired RF (radio frequency) coil. A rechargeable internal battery and a parameter memory component were introduced to the implanted neural stimulator. As a result, the external component was not necessary during the stimulation cycles. The implantable stimulator was implemented with IC chips and the electronics, except for the stimulation electrodes, were hermetically packaged in a biocompatible metal case. A polyimide-based gold electrode array was used for realization of the animal implantation test using retinal prosthesis approach.This work was supported by the Korean Science and Engineering Foundation (KOSEF) through the Nano Bioelectronics and Systems Research Center (NBS-ERC) of Seoul National University under Grant R11-2000-075-01001-0 and by the Ministry of Health & Welfare, Republic of Korea through the Nano Artificial Vision Research Center under Grant of the Korea Health 21 R&D Project (A050251)

Ovarian Cancer Prognostic Prediction Model Using RNA Sequencing Data

Ovarian cancer is one of the leading causes of cancer-related deaths in gynecological malignancies. Over 70% of ovarian cancer cases are high-grade serous ovarian cancers and have high death rates due to their resistance to chemotherapy. Despite advances in surgical and pharmaceutical therapies, overall survival rates are not good, and making an accurate prediction of the prognosis is not easy because of the highly heterogeneous nature of ovarian cancer. To improve the patient’s prognosis through proper treatment, we present a prognostic prediction model by integrating high-dimensional RNA sequencing data with their clinical data through the following steps: gene filtration, pre-screening, gene marker selection, integrated study of selected gene markers and prediction model building. These steps of the prognostic prediction model can be applied to other types of cancer besides ovarian cancer

Effect of BRCA mutational status on survival outcome in advanced-stage high-grade serous ovarian cancer

Objective To evaluate impact of germline BRCA mutational status on prognosis in patients with advanced ovarian cancer. Methods A total of 128 patients diagnosed with FIGO stage III-IV high-grade serous ovarian cancer (HGSOC) between 2008 and 2017 and underwent BRCA1/2 gene testing at the time of or within two years from cancer diagnosis were included in this study. We compared patients clinicopathological characteristics and survival outcomes after primary treatment according to germline BRCA mutational status. Treatment-related factors that might affect patients survival outcome were also investigated. Results Germline BRCA1/2 mutations were observed in 51 women (39.8%). There were no differences in age and serum CA-125 levels at the time of HGSOC diagnosis, use of neoadjuvant chemotherapy (NAC), extent of debulking surgery, and overall survival (OS) between the BRCA mutation and wild-type BRCA groups. In contrast, the BRCA mutation group displayed longer progression-free survival (PFS) (median, 22.9 vs. 16.9 months, P = 0.001). Multivariate analyses identified germline BRCA1/2 mutation as an independent favorable prognostic factor for PFS (adjusted HR, 0.502; 95% CI, 0.318–0.795; P = 0.003). In the wild-type BRCA group, patients who received NAC as the primary treatment had shorter PFS compared to those who received primary debulking surgery (PDS) (median, 14.2 vs. 16.9 months, P = 0.003). However, in the BRCA mutation group, PFS did not differ between the NAC and PDS groups (P = 0.082). Conclusions In advanced-stage HGSOC, patients with germline BRCA1/2 mutations have better prognosis with longer PFS than those lacking BRCA mutations. Prognosis after NAC was different according to the BRCA mutational status

A highly efficient wide-band-gap host material for blue electrophosphorescent light-emitting devices

We report on an efficient wide-band-gap host material for blue electrophosphorescence devices, namely, 1,2-trans-di-9-carbazolylcyclobutane (DCz). Photophysical studies show that lower-energy excimer formation between the carbazole units can be efficiently suppressed in a DCz film, thus maintaining its high triplet-state energy and inducing an exothermic energy transfer from DCz to iridium(III)bis[(4,6-difluorophenyl)-pyridinato-N,C2]picolinate (FIrpic). Electrophosphorescent devices comprising a FIrpic:DCz emitting layer exhibit a superior performance with a maximum external quantum efficiency of 9.8%, a maximum luminance efficiency of 21.5 cd/A, and a maximum power efficiency of 15.0 lm/W at 0.01 mA/cm2.This work was partly supported by the Korea Science and Engineering Foundation (KOSEF) through the National Research Laboratory Program funded by the Ministry of Science and Technology (No. 2006-03246), and by Dongwoo FineChem Co

Clinical implications of neoadjuvant chemotherapy in advanced endometrial cancer: a multi-center retrospective cohort study

Background : The mainstay of endometrial cancer treatment is surgical resection of tumors and postoperative adjuvant treatment is recommended if necessary. However, there is no consensus on the management of unresectable metastatic endometrial cancer. This study aimed to assess the feasibility and effectiveness of neoadjuvant chemotherapy followed by interval debulking surgery (NAC-IDS) in unresectable, metastatic endometrial cancer. Methods : From the endometrial cancer cohorts of four institutions in Korea, we identified patients with International Federation of Gynecology and Obstetrics stages IIIC–IVB endometrial cancer who received NAC-IDS between January 2008 and December 2020. Through a medical record review, we collected patients’ clinicopathological data. Progression-free survival (PFS), overall survival (OS), and the factors affecting survival outcomes were analyzed. Results : Overall, 32 patients were included with endometrioid (n = 18), serous (n = 5), carcinosarcoma (n = 6), and other histological types (n = 3). Among them, 28 (87.5%) patients had stage IVB disease. The most common neoadjuvant chemotherapy (NAC) regimen was paclitaxel-carboplatin (n = 25, 78.1%), which was administered for a median of six cycles. While 26 (81.3%) patients showed an objective response, two (6.3%) progressed despite NAC. At the time of interval debulking surgery (IDS), 23 (71.9%) patients achieved complete cytoreduction. During 31.0 months of the median follow-up, there were 23 recurrences and 11 deaths, corresponding to a median PFS of 19.7 months and a 3-year OS rate of 69.7%. In multivariate analyses, non-endometrioid histology and residual tumor after IDS were identified as independent poor prognostic factors for PFS (adjusted hazard ratio [HR], 7.322; P < 0.001 and 5.934; P = 0.001, respectively). Multivariate analysis for OS could not be conducted because of the small number of events, although non-endometrioid histology was the only factor associated with worse OS in univariate analysis (adjusted HR, 4.523; P = 0.032). Conclusions : NAC-IDS may be a treatment option for unresectable metastatic endometrial cancer. Tumor histology and the possibility of complete cytoreduction are the primary considerations for NAC-IDS

Simulation study of dose enhancement in a cell due to nearby carbon and oxygen in particle radiotherapy

The aim of this study is to investigate the dose-deposition enhancement by alpha-particle irradiation in a cellular model using carbon and oxygen chemical compositions.A simulation study was performed to study dose enhancement due to carbon and oxygen for a human cell where Geant4 code used for the alpha-particle irradiation to the cellular phantom. The characteristic of dose enhancement in the nucleus and cytoplasm by the alpha-particle radiation was investigated based on concentrations of the carbon and oxygen compositions and was compared with those by gold and gadolinium.The results show that both the carbon and oxygen-induced dose enhancement was found to be more effective than those of gold and gadolinium. We found that the dose-enhancement effect was more dominant in the nucleus than in the cytoplasm if carbon or oxygen is uniformly distributed in a whole cell. In the condition that the added chemical composition was inserted only into the cytoplasm, the effect of the dose enhancement in nucleus becomes weak.We showed that high-stopping-power materials offer a more effective dose-enhancement efficacy and suggest that the carbon nanotubes and oxygenation are promising candidates for dose utilization as dose enhancement tools in particle therapy.Comment: 19 pages, 6 figures, 4 tables. presented to 7th KOREA-JAPAN Joint Meeting on Medical Physics (2014.09.25) accepted to Journal of the Korean Physical Society (2015.03.10

LYL1 gene amplification predicts poor survival of patients with uterine corpus endometrial carcinoma: analysis of the Cancer genome atlas data

Background Somatic amplifications of the LYL1 gene are relatively common occurrences in patients who develop uterine corpus endometrial carcinoma (UCEC) as opposed to other cancers. This study was undertaken to determine whether such genetic alterations affect survival outcomes of UCEC. Methods In 370 patients with UCEC, we analysed clinicopathologic characteristics and corresponding genomic data from The Cancer Genome Atlas database. Patients were stratified according to LYL1 gene status, grouped as amplification or non-amplification. Heightened levels of cancer-related genes expressed in concert with LYL1 amplification were similarly investigated through differentially expressed gene and gene set enrichment analyses. Factors associated with survival outcomes were also identified. Results Somatic LYL1 gene amplification was observed in 22 patients (5.9%) with UCEC. Patients displaying amplification (vs. non-amplification) were significantly older at the time of diagnosis and more often were marked by non-endometrioid, high-grade, or advanced disease. In survival analysis, the amplification subset showed poorer progression-free survival (PFS) and overall survival (OS) rates (3-year PFS: 34.4% vs. 79.9%, P = 0.031; 5-year OS: 25.1% vs. 84.9%, P = 0.014). However, multivariate analyses adjusted for tumor histologic type, grade, and stage did not confirm LYL1 gene amplification as an independent prognostic factor for either PFS or OS. Nevertheless, MAPK, WNT, and cell cycle pathways were significantly enriched by LYL1 gene amplification (P < 0.001, P = 0.002, and P = 0.004, respectively). Conclusions Despite not being identified as an independent prognostic factor in UCEC, LYL1 gene amplification is associated with other poor prognostic factors and correlated with upregulation of cancer-related pathways