752 research outputs found
Lifetime Risks, Projected Numbers, and Adverse Outcomes in Asian Patients With Atrial Fibrillation::A Report From the Taiwan Nationwide AF Cohort Study
AGE-BSA down-regulates endothelial connexin43 gap junctions
<p>Abstract</p> <p>Background</p> <p>Advanced glycation end products generated in the circulation of diabetic patients were reported to affect the function of vascular wall. We examined the effects of advanced glycation end products-bovine serum albumin (AGE-BSA) on endothelial connexin43 (Cx43) expression and gap-junction communication.</p> <p>Results</p> <p>In human aortic endothelial cells (HAEC) treated with a series concentrations of AGE-BSA (0-500 μg/ml) for 24 and 48 hours, Cx43 transcript and Cx43 protein were reduced in a dose dependent manner. In addition, gap-junction communication was reduced. To clarify the mechanisms underlying the down-regulation, MAPKs pathways in HAEC were examined. Both a MEK1 inhibitor (PD98059) and a p38 MAPK inhibitor (SB203580) significantly reversed the reductions of Cx43 mRNA and protein induced by AGE-BSA. Consistently, phosphorylation of ERK and p38 MAPK was enhanced in response to exposure to AGE-BSA. However, all reversions of down-regulated Cx43 by inhibitors did not restore the functional gap-junction communication.</p> <p>Conclusions</p> <p>AGE-BSA down-regulated Cx43 expression in HAEC, mainly through reduced Cx43 transcription, and the process involved activation of ERK and p38 MAPK.</p
Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study
An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1°C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31 ± 2.07% and 82.81 ± .98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis
Secondary Metabolites from the Leaves of Aquilaria agallocha
Twelve compounds, including three flavonoids, 5-hydroxy-4¢,7- dimethoxyflavone (1) [22], luteolin-7,3¢,4¢-trimethyl ether (2) and 5,3¢- dihydroxy-7,4¢-dimethoxyflavone (3), five benzenoids, methylparaben (4), vanillic acid (5), p-hydroxybenzoic acid (6), syringic acid (7), and isovanillic acid (8) and four steroids, b-sitosterol (9), stigmasterol (10), b-sitostenone (11) and stigmasta-4,22-dien-3- one (12) were isolated from the leaves of Aquilaria agallocha (Thymelaeaceae). All of these compounds (1-12) were obtained for the first time from the leaves of this plant
Evaluation of prognostic factors and the role of chemotherapy in unfavorable carcinoma of unknown primary site: a 10-year cohort study
<p>Abstract</p> <p>Background</p> <p>Carcinoma of unknown primary site (CUP) has a poor prognosis and the prognostic factors in these patients are not well established. Furthermore, there are no selection criteria for patients who should benefit from chemotherapy.</p> <p>Methods</p> <p>The medical records of 179 CUP patients who were treated at Taipei Veterans General Hospital from 2000 to 2009 were reviewed. Factors associated with survival were determined by Kaplan-Meier analysis. Differences between the groups with and without palliative chemotherapy were analyzed.</p> <p>Results</p> <p>Univariate analysis revealed multiple prognostic factors, including performance status, lung metastasis, number of metastatic organs, serum albumin, corrected serum calcium, lactate dehydrogenase (LDH), sodium, and cholesterol levels, palliative chemotherapy, and white blood cell and lymphocyte counts. Multivariate analysis showed that performance status < 2, serum albumin level ≥ 3.5 g/dl, corrected serum calcium level < 10.7 mg/dl, single metastatic organ, and palliative chemotherapy were independent factors of better prognosis. Patients with better performance status, higher serum albumin, and lower serum LDH levels had significantly greater benefit from palliative chemotherapy.</p> <p>Conclusions</p> <p>Certain patients with unfavorable CUP will have better survival. Identification of patients with unfavorable CUP who could benefit from palliative chemotherapy warrants future prospective studies.</p
Prevalence of PIK3CA mutations in Taiwanese patients with breast cancer: a retrospective next-generation sequencing database analysis
BackgroundBreast cancer is the most common cancer type that affects women. In hormone receptor–positive (HR+), human epidermal growth factor receptor 2−negative (HER2–) advanced breast cancer (ABC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) is the most frequently mutated gene associated with poor prognosis. This study evaluated the frequency of PIK3CA mutations in the Taiwanese breast cancer population.MethodologyThis is a retrospective study; patient data were collected for 2 years from a next-generation sequencing database linked to electronic health records (EHRs). The primary endpoint was the regional prevalence of PIK3CA mutation. The secondary endpoints were to decipher the mutation types across breast cancer subtype, menopausal status, and time to treatment failure after everolimus (an mTOR inhibitor) or cyclin-dependent kinase 4/6 (CDK4/6) inhibitor treatment.ResultsPIK3CA mutations were identified in 278 of 728 patients (38%). PIK3CA mutations were reported in 43% of patients with HR−/HER2+ subtype and 42% of patients with HR+/HER2– postmenopausal status. A lower prevalence of PIK3CA mutations was observed in triple-negative (27%) and HR+/HER2– premenopausal patients (29%). The most common mutation was at exon 20 (H1047R mutation, 41.6%), followed by exon 9 (E545K mutation, 18.9% and E542K mutation, 10.3%). Among patients treated with CDK4/6 inhibitors, the median time to treatment failure was 12 months (95% CI: 7-21 months) in the PIK3CA mutation cohort and 16 months (95% CI: 11-23 months) in the PIK3CA wild-type cohort, whereas patients receiving an mTOR inhibitor reported a median time to treatment failure of 20.5 months (95% CI: 8-33 months) in the PIK3CA mutation cohort and 6 months (95% CI: 2-9 months) in the PIK3CA wild-type cohort.ConclusionA high frequency of PIK3CA mutations was detected in Taiwanese patients with breast cancer, which was consistent with previous studies. Early detection of PIK3CA mutations might influence therapeutic decisions, leading to better treatment outcomes
MJ-66 induces malignant glioma cells G2/M phase arrest and mitotic catastrophe through regulation of cyclin B1/Cdk1 complex
Malignant gliomas are among the most devastating cancers as they are resistant to many kinds of treatment. Despite recent advances in the diagnosis and treatment, the prognosis of patients remains very poor and the development of new drug is urgently needed. Here, we report that a synthetic quinazolinone analog 2-(naphthalene-1-yl)-6-pyrrolidinyl-4-quinazolinone (MJ-66) induced glioma cell death. Immunofluorescence staining showed that MJ-66-induced cell death was associated with multinucleated phenotype and multipolar spindles that were typical characteristics of mitotic catastrophe. Flow cytometry analysis revealed that MJ-66 caused glioma cell cycle arrest at G2/M phase and increased the proportion of polyploidy cells. Western blotting indicated that the expression of cyclin B1, Cdk1 pY15 and Cdk1 increased after treatment with MJ-66. MJ-66 effectively inhibited tumor growth and induced apoptosis in the xenograft animal model of U87 human glioma cells. Together, these results suggest that MJ-66 inhibited malignant gliomas growth through inducing mitotic catastrophe by interference with G2/M cell cycle checkpoint which may open a new avenue for the treatment of malignant gliomas
Aberrant Sensory Gating of the Primary Somatosensory Cortex Contributes to the Motor Circuit Dysfunction in Paroxysmal Kinesigenic Dyskinesia
Paroxysmal kinesigenic dyskinesia (PKD) is conventionally regarded as a movement disorder (MD) and characterized by episodic hyperkinesia by sudden movements. However, patients of PKD often have sensory aura and respond excellently to antiepileptic agents. PRRT2 mutations, the most common genetic etiology of PKD, could cause epilepsy syndromes as well. Standing in the twilight zone between MDs and epilepsy, the pathogenesis of PKD is unclear. Gamma oscillations arise from the inhibitory interneurons which are crucial in the thalamocortical circuits. The role of synchronized gamma oscillations in sensory gating is an important mechanism of automatic cortical inhibition. The patterns of gamma oscillations have been used to characterize neurophysiological features of many neurological diseases, including epilepsy and MDs. This study was aimed to investigate the features of gamma synchronizations in PKD. In the paired-pulse electrical-stimulation task, we recorded the magnetoencephalographic data with distributed source modeling and time-frequency analysis in 19 patients of newly-diagnosed PKD without receiving pharmacotherapy and 18 healthy controls. In combination with the magnetic resonance imaging, the source of gamma oscillations was localized in the primary somatosensory cortex. Somatosensory evoked fields of PKD patients had a reduced peak frequency (p < 0.001 for the first and the second response) and a prolonged peak latency (the first response p = 0.02, the second response p = 0.002), indicating the synchronization of gamma oscillation is significantly attenuated. The power ratio between two responses was much higher in the PKD group (p = 0.013), indicating the incompetence of activity suppression. Aberrant gamma synchronizations revealed the defective sensory gating of the somatosensory area contributes the pathogenesis of PKD. Our findings documented disinhibited cortical function is a pathomechanism common to PKD and epilepsy, thus rationalized the clinical overlaps of these two diseases and the therapeutic effect of antiepileptic agents for PKD. There is a greater reduction of the peak gamma frequency in PRRT2-related PKD than the non-PRRT PKD group (p = 0.028 for the first response, p = 0.004 for the second response). Loss-of-function PRRT2 mutations could lead to synaptic dysfunction. The disinhibiton change on neurophysiology reflected the impacts of PRRT2 mutations on human neurophysiology
Statins and the risk of dementia in patients with atrial fibrillation:a nationwide population-based cohort study
Empirical vs Bayesian approach for estimating haplotypes from genotypes of unrelated individuals
BACKGROUND: The completion of the HapMap project has stimulated further development of haplotype-based methodologies for disease associations. A key aspect of such development is the statistical inference of individual diplotypes from unphased genotypes. Several methodologies for inferring haplotypes have been developed, but they have not been evaluated extensively to determine which method not only performs well, but also can be easily incorporated in downstream haplotype-based association analyses. In this paper, we attempt to do so. Our evaluation was carried out by comparing the two leading Bayesian methods, implemented in PHASE and HAPLOTYPER, and the two leading empirical methods, implemented in PL-EM and HPlus. We used these methods to analyze real data, namely the dense genotypes on X-chromosome of 30 European and 30 African trios provided by the International HapMap Project, and simulated genotype data. Our conclusions are based on these analyses. RESULTS: All programs performed very well on X-chromosome data, with an average similarity index of 0.99 and an average prediction rate of 0.99 for both European and African trios. On simulated data with approximation of coalescence, PHASE implementing the Bayesian method based on the coalescence approximation outperformed other programs on small sample sizes. When the sample size increased, other programs performed as well as PHASE. PL-EM and HPlus implementing empirical methods required much less running time than the programs implementing the Bayesian methods. They required only one hundredth or thousandth of the running time required by PHASE, particularly when analyzing large sample sizes and large umber of SNPs. CONCLUSION: For large sample sizes (hundreds or more), which most association studies require, the two empirical methods might be used since they infer the haplotypes as accurately as any Bayesian methods and can be incorporated easily into downstream haplotype-based analyses such as haplotype-association analyses
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