186 research outputs found
Observational Evidence of EHP Effects on the Melting of Snowpack over the Tibetan Plateau
Observational evidences are presented showing that the Indo-Gangetic Plain (IGP) regions, bounded by the high altitude Himalayan mountains, are subject to heavy loading of absorbing aerosols, i.e., black carbon and dust, which can lead to widespread enhancement warming over the Tibetan Plateau and accelerated snowmelt in the western Tibetan Plateau (WTP) and Himalayas. The two pre-monsoon seasons of 2004 and 2005 were strikingly contrasting in terms of the aerosol loading over IGP. The warming of the TP in 2004 relative to 2005 was widespread, covering most of the WTP and Himalayas. This warming is closely linked to patterns of the snow melt. Consistent with the Elevated Heat Pump hypothesis, we find that increased loading of absorbing aerosols over IGP in the pre-monsoon season is associated with increased heating of the upper troposphere by dynamical feedback induced by aerosol heating, and enhances the rate of snowmelt over Himalayas and the WTP in April-May. Composite analysis with more contrasting years also shows that the heating of the troposphere by elevated dust and black carbon aerosols in the boreal spring can lead to widespread enhanced land-atmosphere warming, and accelerated snow melt in the Himalayas and Tibetan Plateau
Synergistic nanoarchitecture of mesoporous carbon and carbon nanotubes for lithium-oxygen batteries
A rechargeable lithiumโoxygen battery (LOB) operates via the electrochemical formation and decomposition of solid-state Li2O2 on the cathode. The rational design of the cathode nanoarchitectures is thus required to realize high-energy-density and long-cycling LOBs. Here, we propose a cathode nanoarchitecture for LOBs, which is composed of mesoporous carbon (MPC) integrated with carbon nanotubes (CNTs). The proposed design has the advantages of the two components. MPC provides sufficient active sites for the electrochemical reactions and free space for Li2O2 storage, while CNT forests serve as conductive pathways for electron and offer additional reaction sites. Results show that the synergistic architecture of MPC and CNTs leads to improvements in the capacity (~ 18,400 mAh gโ 1), rate capability, and cyclability (~ 200 cycles) of the CNT-integrated MPC cathode in comparison with MPC. ยฉ 2021, The Author(s).1
Primary Polymorphous Low-Grade Adenocarcinoma of Lung Treated by Sleeve Bronchial Resection : A Case Report
We report a surgical case of primary polymorphous low-grade adenocarcinoma (PLGA) of the minor salivary gland-type of the lung. A PLGA originating from the right upper lobar bronchial inlet was successfully treated by sleeve right upper lobectomy. PLGAs are thought to be indolent tumors that are preferentially localized to the palate, and they affect the minor salivary glands almost exclusively. Until now, two cases of distant metastases to the lung have been reported in the English literature. To the best of our knowledge, only one case of PLGA of minor salivary gland-type of the lung without evidence of a previous oropharyngeal primary tumor has been reported in the English literature. But the case was not a single lesion; it was bilateral tumors accompanied by tumors of the cervical lymph nodes. We report here the first case of a single primary PLGA of the minor salivary gland-type of the lung, which was successfully treated by sleeve bronchial resection of right upper lobe
Characteristics, Outcomes and Predictors of Long-Term Mortality for Patients Hospitalized for Acute Heart Failure: A Report From the Korean Heart Failure Registry
BACKGROUND AND OBJECTIVES: Acute heart failure (AHF) is associated with a poor prognosis and it requires repeated hospitalizations. However, there are few studies on the characteristics, treatment and prognostic factors of AHF. The aims of this study were to describe the clinical characteristics, management and outcomes of the patients hospitalized for AHF in Korea.
SUBJECTS AND METHODS: We analyzed the clinical data of 3,200 hospitalization episodes that were recorded between June 2004 and April 2009 from the Korean Heart Failure (KorHF) Registry database. The mean age was 67.6ยฑ14.3 years and 50% of the patients were female.
RESULTS: Twenty-nine point six percent (29.6%) of the patients had a history of previous HF and 52.3% of the patients had ischemic heart disease. Left ventricular ejection fraction (LVEF) was reported for 89% of the patients. The mean LVEF was 38.5ยฑ15.7% and 26.1% of the patients had preserved systolic function (LVEF โฅ50%), which was more prevalent in the females (34.0% vs. 18.4%, respectively, p<0.001). At discharge, 58.6% of the patients received beta-blockers (BB), 53.7% received either angiotensin converting enzyme-inhibitors or angiotensin receptor blockers (ACEi/ARB), and 58.4% received both BB and ACEi/ARB. The 1-, 2-, 3- and 4-year mortality rates were 15%, 21%, 26% and 30%, respectively. Multivariate analysis revealed that advanced age {hazard ratio: 1.023 (95% confidence interval: 1.004-1.042); p=0.020}, a previous history of heart failure {1.735 (1.150-2.618); p=0.009}, anemia {1.973 (1.271-3.063); p=0.002}, hyponatremia {1.861 (1.184-2.926); p=0.007}, a high level of serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) {3.152 (1.450-6.849); p=0.004} and the use of BB at discharge {0.599 (0.360-0.997); p=0.490} were significantly associated with total death.
CONCLUSION: We present here the characteristics and prognosis of an unselected population of AHF patients in Korea. The long-term mortality rate was comparable to that reported in other countries. The independent clinical risk factors included age, a previous history of heart failure, anemia, hyponatremia, a high NT-proBNP level and taking BB at discharge.ope
Mesenchymal Stem Cells Transfer Mitochondria to the Cells with Virtually No Mitochondrial Function but Not with Pathogenic mtDNA Mutations
It has been reported that human mesenchymal stem cells (MSCs) can transfer mitochondria to the cells with severely compromised mitochondrial function. We tested whether the reported intercellular mitochondrial transfer could be replicated in different types of cells or under different experimental conditions, and tried to elucidate possible mechanism. Using biochemical selection methods, we found exponentially growing cells in restrictive media (uridineโ and bromodeoxyuridine [BrdU]+) during the coculture of MSCs (uridine-independent and BrdU-sensitive) and 143B-derived cells with severe mitochondrial dysfunction induced by either long-term ethidium bromide treatment or short-term rhodamine 6G (R6G) treatment (uridine-dependent but BrdU-resistant). The exponentially growing cells had nuclear DNA fingerprint patterns identical to 143B, and a sequence of mitochondrial DNA (mtDNA) identical to the MSCs. Since R6G causes rapid and irreversible damage to mitochondria without the removal of mtDNA, the mitochondrial function appears to be restored through a direct transfer of mitochondria rather than mtDNA alone. Conditioned media, which were prepared by treating mtDNA-less 143B ฯ0 cells under uridine-free condition, induced increased chemotaxis in MSC, which was also supported by transcriptome analysis. Cytochalasin B, an inhibitor of chemotaxis and cytoskeletal assembly, blocked mitochondrial transfer phenomenon in the above condition. However, we could not find any evidence of mitochondrial transfer to the cells harboring human pathogenic mtDNA mutations (A3243G mutation or 4,977 bp deletion). Thus, the mitochondrial transfer is limited to the condition of a near total absence of mitochondrial function. Elucidation of the mechanism of mitochondrial transfer will help us create a potential cell therapy-based mitochondrial restoration or mitochondrial gene therapy for human diseases caused by mitochondrial dysfunction
Efficacy of High-dose Chemotherapy and Autologous Stem Cell Transplantation in Patients with Relapsed Medulloblastoma: A Report on The Korean Society for Pediatric Neuro-Oncology (KSPNO)-S-053 Study
The efficacy and toxicity of high-dose chemotherapy and autologous stem cell transplantation (HDCT/ASCT) were investigated for improving the outcomes of patients with relapsed medulloblastoma. A total of 15 patients with relapsed medulloblastoma were enrolled in the KSPNO-S-053 study from May 2005 to May 2007. All patients received approximately 4 cycles of salvage chemotherapy after relapse. Thirteen underwent HDCT/ASCT; CTE and CM regimen were employed for the first HDCT (HDCT1) and second HDCT (HDCT2), respectively, and 7 underwent HDCT2. One transplant related mortality (TRM) due to veno-occlusive disease (VOD) occurred during HDCT1 but HDCT2 was tolerable with no further TRM. The 3-yr overall survival probability and event-free survival rates ยฑ95% confidence intervals (CI) were 33.3ยฑ12.2% and 26.7% ยฑ11.4%, respectively. When analysis was confined to only patients who had a complete response (CR) or partial response (PR) prior to HDCT, the probability of 3-yr overall survival rates ยฑ95% CI was 40.0ยฑ15.5%. No patients with stable disease (SD) or progressive disease (PD) survived. Survival rates from protocol KSPNO-S-053 are encouraging and show that tumor status prior to HDCT/ASCT is an important factor to consider for improving survival rates of patients with relapsed medulloblastoma
Molecular diagnosis of hereditary spherocytosis by multi-gene target sequencing in Korea: matching with osmotic fragility test and presence of spherocyte
Background
Current diagnostic tests for hereditary spherocytosis (HS) focus on the detection of hemolysis or indirectly assessing defects of membrane protein, whereas direct methods to detect protein defects are complicated and difficult to implement. In the present study, we investigated the patterns of genetic variation associated with HS among patients clinically diagnosed with HS.
Methods
Multi-gene targeted sequencing of 43 genes (17 RBC membrane protein-encoding genes, 20 RBC enzyme-encoding genes, and six additional genes for the differential diagnosis) was performed using the Illumina HiSeq platform.
Results
Among 59 patients with HS, 50 (84.7%) had one or more significant variants in a RBC membrane protein-encoding genes. A total of 54 significant variants including 46 novel mutations were detected in six RBC membrane protein-encoding genes, with the highest number of variants found in SPTB (nโ=โ28), and followed by ANK1 (nโ=โ19), SLC4A1 (nโ=โ3), SPTA1 (nโ=โ2), EPB41 (nโ=โ1), and EPB42 (nโ=โ1). Concurrent mutations of genes encoding RBC enzymes (ALDOB, GAPDH, and GSR) were detected in three patients. UGT1A1 mutations were present in 24 patients (40.7%). Positive rate of osmotic fragility test was 86.8% among patients harboring HS-related gene mutations.
Conclusions
This constitutes the first large-scaled genetic study of Korean patients with HS. We demonstrated that multi-gene target sequencing is sensitive and feasible that can be used as a powerful tool for diagnosing HS. Considering the discrepancies of clinical and molecular diagnoses of HS, our findings suggest that molecular genetic analysis is required for accurate diagnosis of HS.Support was provided by: the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIT) (NRF-2017R1A2A1A17069780) http://www.nrf.re.kr/
- โฆ