146 research outputs found
Increased ATP generation in the host cell is required for efficient vaccinia virus production
To search for cellular genes up-regulated by vaccinia virus (VV) infection, differential display-reverse transcription-polymerase chain reaction (ddRT-PCR) assays were used to examine the expression of mRNAs from mock-infected and VV-infected HeLa cells. Two mitochondrial genes for proteins that are part of the electron transport chain that generates ATP, ND4 and CO II, were up-regulated after VV infection. Up-regulation of ND4 level by VV infection was confirmed by Western blotting analysis. Up-regulation of ND4 was reduced by the MAPK inhibitor, apigenin, which has been demonstrated elsewhere to inhibit VV replication. The induction of ND4 expression occurred after viral DNA replication since ara C, an inhibitor of poxviral DNA replication, could block this induction. ATP production was increased in the host cells after VV infection. Moreover, 4.5 μM oligomycin, an inhibitor of ATP production, reduced the ATP level 13 hr after virus infection to that of mock-infected cells and inhibited viral protein expression and virus production, suggesting that increased ATP production is required for efficient VV production. Our results further suggest that induction of ND4 expression is through a Bcl-2 independent pathway
Recommended from our members
An Investigation of Factors Affecting Financial Performance of Taiwanese International Tourist Hotels
This study adopts moving average regression and panel data regression to explore the factors affecting the financial performance of international tourist hotels in Taiwan. First, we use the unit root test to examine the data in moving average regression and in panel data regression and then use the Hausman test to examine whether the fixed-effects or random-effects model is suitable for panel data regression. Second, we employ the Lagrangian multiplier (LM) test to confirm that panel data regression is better. The findings show that domestic visitors, occupancy rate, operation year, and joining a chain system are the four key factors affecting financial performance
Using T-cell repertoire profiles as predictor in a primary mucosal melanoma
Dear Editor, Primary mucosal melanoma is a rare subtype of melanoma that carries poor prognosis. Traditional treatment options of mucosal melanoma are surgery, radiation, and chemotherapy; but the overall survival remains low.1 Cytotoxic T‐lymphocyte associated protein 4 (CLTA‐4) and programmed cell death protein 1 (PD‐1), both inhibitory immune checkpoints commonly seen on activated T cells, have been found to be promising targets for treatment of advanced cancers.2 However, the efficacy and response to immunotherapy in mucosal melanoma remains unknown. Herein, we report a case involving a patient, who was a 70‐year‐old male and referred to Taipei Medical University Hospital with confirmed diagnosis of mucosa melanoma over hard plate of mouth. The patient was admitted and subjected to anti‐PD‐1 immunotherapy (pembrolizumab 200 mg every 3 weeks) (Figure 1A). Serial imaging of primary malignant melanoma of the hard palate showed that the tumor size gradually decreased after treatment with pembrolizumab, suggesting partial response/stable disease secondary to continuous immunotherapy (Figure 1B). However, after seventh cycle of treatment, magnetic resonance imaging (MRI) revealed enlarged previous known metastatic lesions and new tumor nodules in brain (Figure 1B). The patient received stereotactic radiation therapy before treatment cycle 14 (Figure 1A). Although the primary metastatic brain lesions were smaller and stationary after radiotherapy, the following brain MRI displayed several hyperdensity masses in the right frontal lobe with perifocal edema and mild mass effect (Figure 1B). Subsequently, patient suffered from infection and respiratory distress and died 2 months after 17th cycle of pembrolizumab therapy
Using T-cell repertoire profiles as predictor in a primary mucosal melanoma
Dear Editor, Primary mucosal melanoma is a rare subtype of melanoma that carries poor prognosis. Traditional treatment options of mucosal melanoma are surgery, radiation, and chemotherapy; but the overall survival remains low.1 Cytotoxic T‐lymphocyte associated protein 4 (CLTA‐4) and programmed cell death protein 1 (PD‐1), both inhibitory immune checkpoints commonly seen on activated T cells, have been found to be promising targets for treatment of advanced cancers.2 However, the efficacy and response to immunotherapy in mucosal melanoma remains unknown. Herein, we report a case involving a patient, who was a 70‐year‐old male and referred to Taipei Medical University Hospital with confirmed diagnosis of mucosa melanoma over hard plate of mouth. The patient was admitted and subjected to anti‐PD‐1 immunotherapy (pembrolizumab 200 mg every 3 weeks) (Figure 1A). Serial imaging of primary malignant melanoma of the hard palate showed that the tumor size gradually decreased after treatment with pembrolizumab, suggesting partial response/stable disease secondary to continuous immunotherapy (Figure 1B). However, after seventh cycle of treatment, magnetic resonance imaging (MRI) revealed enlarged previous known metastatic lesions and new tumor nodules in brain (Figure 1B). The patient received stereotactic radiation therapy before treatment cycle 14 (Figure 1A). Although the primary metastatic brain lesions were smaller and stationary after radiotherapy, the following brain MRI displayed several hyperdensity masses in the right frontal lobe with perifocal edema and mild mass effect (Figure 1B). Subsequently, patient suffered from infection and respiratory distress and died 2 months after 17th cycle of pembrolizumab therapy
Sustained Robust Exciton Emission in Suspended Monolayer WSe_2 within the Low Carrier Density Regime for Quantum Emitter Applications
The development of semiconductor optoelectronic devices is moving toward low
power consumption and miniaturization, especially for high-efficiency quantum
emitters. However, most of these quantum sources work at low carrier density
region, where the Shockley-Read-Hall recombination may dominant and seriously
reduce the emission efficiency. In order to diminish the affection of carrier
trapping and sustain a strong photoluminescence emission under low power
pumping condition, we investigated on the influence of Suspending to
monolayered tungsten diselenide, novel two-dimensional quantum material. Not
only the PL intensity, but also the fundamental photoluminescence quantum yield
has exhibited a huge, order-scale enhancement through suspending, even
surprisingly, we found the PLQY improvement revealed far significantly under
small pumping power and came out an exponential increase tendency toward even
lower carrier density region. With its strong excitonic effect, suspended WSe_2
offers a solution to reduce carrier trapping and participate in non-radiative
processes. Moreover, in the low-power range where SRH recombination dominates,
suspended WSe_2 exhibited remarkably higher percentage of excitonic radiation
compared to contacted WSe_2. Herein, we quantitatively demonstrate the
significance of suspended WSe_2 monolayer at low carrier density region,
highlighting its potential for developing compact, low-power quantum emitters
in the future
遊客生態旅遊認知對環境衝擊敏感度影響之研究
生態旅遊雖然將遊憩活動對生態環境之衝擊減至最低,仍會造成一些生態上的改變甚至環境的衝擊。遊憩衝擊是一種不滿意的體驗,遊客對旅遊地點內衝擊的不同認知將會影響遊客對地點的評價。經營者有必要瞭解遊客對環境衝擊的認知程度,作為經營管理的參考。
本研究欲瞭解生態旅遊遊客的生態旅遊認知是否會影響其對環境的衝擊敏感度,本研究選擇美國及台灣兩個不同文化的受訪者,分別於台灣的國家森林步道以及美國的阿帕拉契步道實際調查衝擊程度並訪問當地旅遊之遊客,並將所得之數據資料作整理與分析。主要研究結果如下: 1.台潛實質環境衝擊較美國嚴童。2.遊客對於生態旅遊之認知是正面的。3.生態旅遊認知對於環境衝擊會有部分影響。本研究希望根據分析的結果提出經營管理之策略,以提供未來在發展生態旅遊上有所貢獻。The concept of eco-tourism has reduced the recreational impacts compare to the mass tourism activities. However, the impact still happens during various kinds of eco-tourism areas. Recreational impact will induce negative experience to visitor's satisfaction. The cognition of the environmental impacts due to visitors' use will influences visitors' evaluation to the recreational site. There, recreational managers have to understand the impacts and their influential factors to build manaferial parameters. The purpose of this study to test the relationship between visitors' ecological concern and visitors' environmental impact sensitivity. With these test, this study tries to depict the effect of visitors' ecological concern on visitors' environmental impact sensitivity. Both visitors in Taiwan and in the US with different cultural backgrounds will be selected as study subjects. The National Forestry Trail in Taiwan and the Appalachian Trail in the US will be selected as testing sites. The impact type, level...and visitor' on-site cognition will be recorded for further analyses. Base on the study findings, three conclusions were drawn as following: 1. Recreational impact in Taiwan is more serious than in the US. 2. Visitor's ecological concern was positive. 3. Visitor's ecological concern had significant influences on visitors' environmental impact sensitivity. This proposal expects to propose suggestions by the study results to benefit the development of eco-tourism of Taiwan
Association of ORAI1 Haplotypes with the Risk of HLA-B27 Positive Ankylosing Spondylitis
Ankylosing spondylitis (AS) is a chronic inflammation of the sacroiliac joints, spine and peripheral joints. The aetiology of ankylosing spondylitis is still unclear. Previous studies have indicated that genetics factors such as human leukocyte antigen HLA-B27 associates to AS susceptibility. We carried out a case-control study to determine whether the genetic polymorphisms of ORAI1 gene, a major component of store-operated calcium channels that involved the regulation of immune system, is a susceptibility factor to AS in a Taiwanese population. We enrolled 361 AS patients fulfilled the modified New York criteria and 379 controls from community. Five tagging single nucleotides polymorphisms (tSNPs) at ORAI1 were selected from the data of Han Chinese population in HapMap project. Clinical statuses of AS were assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global Index (BAS-G). Our results indicated that subjects carrying the minor allele homozygote (CC) of the promoter SNP rs12313273 or TT homozygote of the SNP rs7135617 had an increased risk of HLA-B27 positive AS. The minor allele C of 3′UTR SNP rs712853 exerted a protective effect to HLA-B27 positive AS. Furthermore, the rs12313273/rs7135617 pairwise allele analysis found that C-G (OR 1.69, 95% CI 1.27, 2.25; p = 0.0003) and T-T (OR 1.75, 95% CI 1.36, 2.27; p<0.0001) haplotypes had a significantly association with the risk of HLA-B27-positive AS in comparison with the T-G carriers. This is the first study that indicate haplotypes of ORAI1 (rs12313273 and rs7135617) are associated with the risk of HLA-B27 positive AS
Cancer and mTOR inhibitors in kidney transplantation recipients
Background Previous studies show that mTOR inhibitors decrease the risk of cancer development after kidney transplantation. However, the effect of cumulative doses of mTOR inhibitors on cancer after kidney transplantation is not well known. Methods In the current study, patients were registered into a national database in Taiwan. Between year 2000 and 2013, 4,563 patients received kidney transplantation. They were divided into two groups, according to mTOR inhibitors usage. The cumulative dose of mTOR inhibitors was recorded. Patients were followed-up until de novo cancer development, death, or the end of 2014. Results Patients were divided into two groups: mTOR inhibitors users (study group, n = 828) and mTOR inhibitors non-users (control group, n = 3,735). The median follow-up duration was 7.8 years. The risk of de novo cancer (hazards ratio (HR) 0.80, 95% CI [0.60–1.09], p = 0.16) and risk of death (HR 1.14, 95% CI [0.82–1.60], p = 0.43) was not different between mTOR inhibitor user and non-user groups. Neither high- nor low-dose exposure to mTOR inhibitors was associated with increased risk of cancer or mortality. Analysis of cancer subtypes showed no influence by mTOR inhibitors. In addition, the cause of mortality was not significantly different between the two groups. Discussion We could not find the association of mTOR inhibitors use and risk of de novo cancer development or mortality in patients with kidney transplantation in Chinese patients. Cumulative exposure to mTOR inhibitors did not change the results
Design and synthesis of gambogic acid analogs as potent cytotoxic and anti-inflammatory agents
Prenyl- and pyrano-xanthones derived from 1,3,6-trihydroxy-9H-xanthen-9-one, a basic backbone of gambogic acid (GA), were synthesized and evaluated for in vitro cytotoxic effects against four human cancer cell lines (KB, KBvin, A549, and DU-145) and anti-inflammatory activity toward superoxide anion generation and elastase release by human neutrophils in response to fMLP/CB. Among them, prenylxanthones 7-13 were generally less active than pyranoxanthones 14-21 in both anticancer and anti-inflammatory assays. Furthermore, two angular 3,3-dimethypyranoxanthones (16 and 20) showed the greatest and selective activity against the KBvin multidrug resistant (MDR) cell line with IC50 values of 0.9 and 0.8 μ g/mL, respectively. An angular 3-methyl-3-prenylpyranoxanthone (17) selectively inhibited elastase release with 200 times more potency than phenylmethylsulfonyl fluoride (PMSF), the positive control
- …