anh hoang - Academia.edu (original) (raw)

Papers by anh hoang

International Journal of Science and Research (IJSR), 2016

An experimental analysis was carried out to investigate two types of non edible oils (Hazelnut an... more An experimental analysis was carried out to investigate two types of non edible oils (Hazelnut and Corn) blended with conventional diesel fuel approximately with proportions of 5%, 10 % , 15%, 20% and 25% by volume in a 4-stroke single cylinder, vertical, water cooled, Compression Ignition engine. Number of experimental trials were conducted with the above bio-diesel blends as fuel operated in the engine working at all loads from minimum to maximum. An analysis was made to compare the results such as exhaust emission characteristics like NOx emissions, CO emissions, smoke density, and total and partially unburned hydrocarbons. Performance parameters like brake specific fuel consumption(BSFC), brake Thermal efficiency(BTHE), and exhaust gas temperatures(EGT) for all blends prepared by blending the bio-diesels mentioned above with conventional diesel fuel separately with different proportions listed in the work. In this work CI engine is giving better performance with blend B20 for both diesels used as fuel when compare with remaining blends of both bio-diesels. But when compare with these B20 blends are showing marginal decrease in the performance parameters. Engine working with bio-diesel blends as fuel are showing noticeable reduction in exhaust emissions like carbon monoxides (CO), hydro carbons(HC) and slight increase in oxides of nitrogen(NOx) when compared with conventional neat diesel fuel.. Bio-diesel blend prepared from hazelnut bio-diesel showing better properties next to diesel fuel when compared with remaining bio-diesels used in the present work. This blend is showing better engine performance and decreased engine emissions when compared with Corn bio-diesel blends. After hazel nut oil immediately corn is giving better performance.

European heart journal, Jan 26, 2017

The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL... more The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL biology. Therefore there is an urgent need to comprehensively investigate HDL metabolism to enable the development of effective HDL-centric therapies. To identify novel regulators of HDL metabolism, we performed a joint analysis of human genetic, transcriptomic, and plasma HDL-cholesterol (HDL-C) concentration data and identified a novel association between trafficking protein, kinesin binding 2 (TRAK2) and HDL-C concentration. Here we characterize the molecular basis of the novel association between TRAK2 and HDL-cholesterol concentration. Analysis of lymphocyte transcriptomic data together with plasma HDL from the San Antonio Family Heart Study (n = 1240) revealed a significant negative correlation between TRAK2 mRNA levels and HDL-C concentration, HDL particle diameter and HDL subspecies heterogeneity. TRAK2 siRNA-mediated knockdown significantly increased cholesterol efflux to apoli...

Journal of Visualized Experiments, 2012

Cholesterol content of cells must be maintained within the very tight limits, too much or too lit... more Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of cellular membranes, apoptosis and necrosis 1. Cells can source cholesterol from intracellular synthesis and from plasma lipoproteins, both sources are sufficient to fully satisfy cells' requirements for cholesterol. The processes of cholesterol synthesis and uptake are tightly regulated and deficiencies of cholesterol are rare 2. Excessive cholesterol is more common problem 3. With the exception of hepatocytes and to some degree adrenocortical cells, cells are unable to degrade cholesterol. Cells have two options to reduce their cholesterol content: to convert cholesterol into cholesteryl esters, an option with limited capacity as overloading cells with cholesteryl esters is also toxic, and cholesterol efflux, an option with potentially unlimited capacity. Cholesterol efflux is a specific process that is regulated by a number of intracellular transporters, such as ATP binding cassette transporter proteins A1 (ABCA1) and G1 (ABCG1) and scavenger receptor type B1. The natural acceptor of cholesterol in plasma is high density lipoprotein (HDL) and apolipoprotein A-I. The cholesterol efflux assay is designed to quantitate the rate of cholesterol efflux from cultured cells. It measures the capacity of cells to maintain cholesterol efflux and/or the capacity of plasma acceptors to accept cholesterol released from cells. The assay consists of the following steps. Step 1: labelling cellular cholesterol by adding labelled cholesterol to serum-containing medium and incubating with cells for 24-48 h. This step may be combined with loading of cells with cholesterol. Step 2: incubation of cells in serum-free medium to equilibrate labelled cholesterol among all intracellular cholesterol pools. This stage may be combined with activation of cellular cholesterol transporters. Step 3: incubation of cells with extracellular acceptor and quantitation of movement of labelled cholesterol from cells to the acceptor. If cholesterol precursors were used to label newly synthesized cholesterol, a fourth step, purification of cholesterol, may be required. The assay delivers the following information: (i) how a particular treatment (a mutation, a knock-down, an overexpression or a treatment) affects the capacity of cell to efflux cholesterol and (ii) how the capacity of plasma acceptors to accept cholesterol is affected by a disease or a treatment. This method is often used in context of cardiovascular research, metabolic and neurodegenerative disorders, infectious and reproductive diseases.

Journal of Pharmacology and Experimental Therapeutics, 2012

Raising high-density lipoprotein (HDL) levels is proposed as an attractive target to treat cardio... more Raising high-density lipoprotein (HDL) levels is proposed as an attractive target to treat cardiovascular disease. However, a number of clinical studies examining the effect of HDL-raising therapies have been prematurely halted due to futility. Therefore there is a need for alternative therapies. Infusion of reconstituted HDL (rHDL) particles is still considered as a viable approach to increasing HDL levels. In this study we have profiled the antiinflammatory effects of a trimeric-HDL particle. We show that trimeric apoA-I and rHDL particles promote cholesterol efflux to a similar rate as native apoA-I particles in both ABCA1-dependent and-independent pathways. Trimeric particles inhibited ICAM-1 and VCAM-1 expression and the ability of the endothelium to capture monocytes under shear flow. Monocyte activation, CD11bdependent adhesion, and monocyte recruitment under shear flow conditions were perturbed by the trimeric particles. Our data suggest that trimeric rHDL particles can be constructed without any loss of function, preserving the anti-inflammatory effects of HDL that are key to its in vivo actions.

Journal of Lipid Research, 2004

This study was aimed at developing a method for high-efficiency transient transfection of macroph... more This study was aimed at developing a method for high-efficiency transient transfection of macrophages. Seven methods were evaluated for transient transfection of murine macrophage RAW 264.7 cells. The highest transfection efficiency was achieved with DEAE-dextran, although the proportion of cells expressing the reporter gene did not exceed 20%. It was subsequently found that the cytomegalovirus plasmid promoter in these cells becomes methylated. When cells were treated with the methylation inhibitor 5-azacytidine, methylation of the plasmid promoter was abolished and a dose-dependent stimulation of reporter gene expression was observed with expression achieved in more than 80% of cells. Treatment of cells with 5-azacytidine also caused increased efficiency of transfection of macrophages with plasmids driven by RSV, SV40, and EF-1 ␣ promoters and transient transfection of human HepG2 cells. Inhibition of methylation also increased the amount and activity of sterol 27-hydroxylase (CYP27A1) detected in RAW 264.7 cells transfected with a CYP27A1 expression plasmid. Treatment of cells with 5-azacytidine alone did not affect either cholesterol efflux from nontransfected cells or expression of ABCA1 and CYP27A1. However, transfection with CYP27A1 led to a 2-to 4-fold increase of cholesterol efflux. We conclude that treatment with 5-azacytidine can be used for high-efficiency transient transfection of macrophages.-Escher, G.

Journal of Lipid Research, 2002

Physical activity can raise the level of circulating HDL cholesterol. Pre ␤ 1-HDL is thought to b... more Physical activity can raise the level of circulating HDL cholesterol. Pre ␤ 1-HDL is thought to be either the initial acceptor of cellular cholesterol or virtually the first particle in the pathway of the formation of HDL from apolipoprotein A-I and cellular lipids. We have therefore sought to identify pre ␤ 1-HDL in arterial and venous circulations of exercising legs in healthy individuals and in subjects with stable Type 2 diabetes mellitus. Blood samples were taken simultaneously from the femoral artery and vein before and after 25 min cycling exercise. The major findings were, first, that exercise significantly increased plasma concentration of pre ␤ 1-HDL (20% increase, P Ͻ 0.05) and second, that the pre ␤ 1-HDL concentration was significantly higher in the venous compared with the arterial blood both before and after exercise in both diabetics and controls. In the combined population, formation of pre ␤ 1-HDL at rest was 9.9 ؎ 5.2 mg/min and exercise enhanced pre ␤ 1-HDL formation 6.6-fold in both groups.-Sviridov, D., B. Kingwell, A. Hoang, A. Dart, and P. Nestel. Single session exercise stimulates formation of pre ␤ 1-HDL in leg muscle.

The Journal of Clinical Endocrinology & Metabolism, 2008

Background: Low plasma concentration of high-density lipoprotein (HDL) cholesterol is a risk fact... more Background: Low plasma concentration of high-density lipoprotein (HDL) cholesterol is a risk factor for cardiovascular disease and a feature of the metabolic syndrome. Rosuvastatin has been shown to increase HDL cholesterol concentration, but the mechanisms remain unclear.Methods and Results: Twelve men with the metabolic syndrome were studied in a randomized, double-blind, crossover trial of 5-wk therapeutic periods with placebo, 10 mg/d rosuvastatin, or 40 mg/d rosuvastatin, with 2-wk placebo washout between each period. Compared with placebo, there was a significant dose-dependent increase in HDL cholesterol, HDL particle size, and concentration of HDL particles that contain apolipoprotein A-I (LpA-I). The increase in LpA-I concentration was associated with significant dose-dependent reductions in triglyceride concentration and LpA-I fractional catabolic rate, with no changes in LpA-I production rate. There was a significant dose-dependent reduction in the fractional catabolic ra...

Arteriosclerosis, Thrombosis, and Vascular Biology, 2008

Objective—Whereas the anti–inflammatory effects of high-density lipoprotein (HDL) on endothelial ... more Objective—Whereas the anti–inflammatory effects of high-density lipoprotein (HDL) on endothelial cells are well described, such effects on monocytes are less studied.Methods and Results—Human monocytes were isolated from whole blood followed by assessment of CD11b activation/expression and cell adhesion under shear-flow. HDL caused a dose-dependent reduction in the activation of CD11b induced by PMA or receptor-dependent agonists. The constituent of HDL responsible for the antiinflammatory effects on CD11b activation was found to be apolipoprotein A-I (apoA-I). Cyclodextrin, but not cyclodextrin/cholesterol complex, also inhibited PMA-induced CD11b activation implicating cholesterol efflux as the main mechanism. This was further confirmed with the demonstration that cholesterol content of lipid rafts diminished after treatment with the cholesterol acceptors. Blocking ABCA1 with an anti-ABCA1 antibody abolished the effect of apoA-I. Furthermore, monocytes derived from a Tangier disea...

Arteriosclerosis, Thrombosis, and Vascular Biology, 2004

Background— Physical exercise is associated with a decreased risk of cardiovascular disease, whic... more Background— Physical exercise is associated with a decreased risk of cardiovascular disease, which may be partly caused by the effect of exercise on the lipoprotein profile. The most consistent effect of exercise on lipoprotein metabolism is an increase in high-density lipoprotein (HDL). Methods and Results— Parameters of reverse cholesterol transport (RCT) in 25 endurance-trained male athletes were compared with 33 age-matched males enjoying an active lifestyle. V o 2 max was higher in athletes than in controls (53.4±1.2 versus 38.8±1.0 mL/min per kg; P <0.01). The following differences in parameters of RCT were found: (1) plasma HDL cholesterol and apoA-I levels were higher in athletes compared with controls (1.7±0.1 versus 1.4±0.1 mmol/L; P <0.001; and 145±2 versus 128±3 mg/dL; P <0.001, respectively). Both correlated with V o 2 max up to the value of 51 mL/min per kg; (2) preβ 1 -HDL was higher in athletes than in controls (54±4 versus 37±3 μg/mL; P <0.001) and corre...

Tạp chí Y Dược học Cần Thơ

Đặt vấn đề: Kháng sinh là một nhóm thuốc đặc biệt vì việc sử dụng kháng sinh không chỉ ảnh hưởng ... more Đặt vấn đề: Kháng sinh là một nhóm thuốc đặc biệt vì việc sử dụng kháng sinh không chỉ ảnh hưởng đến người bệnh mà còn ảnh hưởng đến cộng đồng. Ở Việt Nam, đây là một nhóm thuốc quan trọng vì bệnh lý nhiễm khuẩn nằm trong số những bệnh đứng hàng đầu cả về tỷ lệ mắc bệnh và tỷ lệ tử vong. MRSA chiếm 82,1 % trong tổng số các chủng S. aureus phân lập là nguyên nhân gây tử vong liên quan viêm phổi bệnh viện. Mục tiêu nghiên cứu: Xác định công thức hợp lực của các cao phân đoạn Trâm Tròn, Xăng Mã, Cò Ke trên hoạt tính kháng MRSA. Đối tượng và phương pháp nghiên cứu: Sử dụng phương pháp khuếch tán đĩa, phương pháp vi pha loãng để xác định hoạt tính kháng MRSA của cao ethanol toàn phần Trâm Tròn, Xăng Mã, Cò Ke và các cao phân đoạn, thử nghiệm SRB chứng minh tính an toàn của cao ethanol toàn phần thực vật trên hai dòng tế bào nguyên bào sợi và tế bào ung thư gan. Chỉ số FIC được tính toán dựa vào phương pháp bàn cờ, xác định khả năng hợp lực của các cao phân đoạn ethyl acetate với nhau trê...

Chemical engineering transactions, 2020

Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly spreading in hospitals. ... more Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly spreading in hospitals. The discovery of a new antibiotic is increasingly difficult due to its huge amount of time and money requirements. Medicinal herbs were used in the treatment of infectious diseases for a long time. Binh Duong province has a rich source of indigenous plants. Traditional remedies of these plants have been used in treating infectious diseases. However, there are very few studies on natural antibiotics in the area. The main purpose of this study is to investigate antibacterial activity of Syzygium glomerulatum collected in Binh Duong on methicillin-resistant Staphylococcus aureus. Agar disc diffusion and micro dilution methods were performed to determine antibacterial activity against MRSA of Syzygium glomerulatum and its ability to combine with vancomycin antibiotic. In addition, the cell toxicity of Syzygium glomerulatum was determined by SRB (Sulforhodamine B). Results showed that the min...

Urban Science, 2019

In Ho Chi Minh City (HCMC, Vietnam), there is now an urgent need for evaluating access to parks i... more In Ho Chi Minh City (HCMC, Vietnam), there is now an urgent need for evaluating access to parks in an effort to ensure better planning within the context of rapid and increasingly privatized urbanization. In this article, we analyze the provision and accessibility to parks in HCMC. To achieve this, the information gathered was then integrated into the geographical information systems (GISs). Based on an Ascending Hierarchical Classification, we were able to identify five different types ranging in their intrinsic characteristics. The accessibility measurements calculated in the GISs show that communities are located an average of at least 879 meters away from parks, which is a relatively short distance. Children have a level of accessibility comparable to that of the overall population. Accessibility also seems to vary greatly throughout the City—populations residing in central districts (planned before 1996) enjoy better accessibility compared to those in peripheral neighborhoods (...

Journal of Lipid Research, 2002

Five mutants of apolipoprotein A-I (apoA-I), apoA-I(Δ63–73), apoA-I(Δ140–150), apoA-I(63–73@140–1... more Five mutants of apolipoprotein A-I (apoA-I), apoA-I(Δ63–73), apoA-I(Δ140–150), apoA-I(63–73@140–150), apoA-I(R149V), and apoA-I(P143A) were compared with human plasma apoA-I for their ability to promote cholesterol and phospholipid efflux from HepG2 cells. A significantly lower capacity to promote cholesterol and phospholipid efflux was observed with lipid-free apoA-I(Δ63–73), while mutations apoA-I(Δ140–150) and apoA-I(P143A) affected phospholipid efflux only. When added as apoA-I/palmitoyloleoyl phosphatidylcholine (POPC) complex, mutations apoA-I(63–73@140–150) and apoA-I(Δ140–150) affected cholesterol efflux. None of the mutations affected α-helicity of the lipid-free mutants or their self-association. Five natural mutations of apoA-I, apoA-I(A95D), apoA-I (Y100H), apoA-I(E110K), apoA-I(V156E), and apoA-I (H162Q) were studied for their ability to bind lipids and promote cholesterol efflux. None of the mutations affected lipid-binding properties, cholesterol efflux, or α-helicity...

International Journal on Advanced Science, Engineering and Information Technology, 2019

Pollution in the maritime field is considered as such a serious problem that scientists, policyma... more Pollution in the maritime field is considered as such a serious problem that scientists, policymakers, and managers are always urged with a desire to find solutions and strategies one way or another to minimize its negative impacts on the environment and the life. Among the effective solutions, the use of fuels with limited-sulfur content or bio-based fuels has been paid much attention to due to their advantages in the use of marine diesel engines. In the current study, a type of fossil diesel fuel with ultra-low sulfur content (ULSD) was mixed with coconut oil (CO) through the ultrasonic treatment under the changes in volume fraction of as-used fuels, the correlation on viscosity selected the rate mixing between ULSD and coconut oil. After 12 minutes of ultrasound treatment, the highest stability of the ULSD-CO emulsion was achieved correspondingly to 97.8% for a mixing rate of 76%(ULSD):24%(CO) along with the distance of 85mm from the containing-vessel bottom to the ultrasound horn tip. Moreover, the spray characteristics including penetration length and a cone angle of ULSD, CO, and ULSD-CO emulsion were also examined and compared to diesel fuel. The similarity of spray characteristics to diesel fuel, containing ultra-low sulfur content and oxygen content, renewability are considered as some advantages of ULSD-CO emulsion as used for diesel engines aiming to meet the stricter requirements of IMO regulations about the strategies of environmental protection.

Biofuel Research Journal, 2019

HIGHLIGHTS Preheated and unpreheated straight Jatropha oil, and fossil diesel fuel were experime... more HIGHLIGHTS Preheated and unpreheated straight Jatropha oil, and fossil diesel fuel were experimentally compared. Spray characteristics, i.e., cone angle and penetration length were investigated. Thermal efficiency and emission parameters were tested at 0 h and after 300 h of engine operation. Trilateral correlation of spray characteristics, combustion parameters, and deposit accumulation in injector orifices was analyzed. Unpreheated straight Jatropha oil cannot be recommended for long term use in diesel engines.

International Journal on Advanced Science, Engineering and Information Technology, 2018

Alternative fuels need to satisfy the strict requirements of the use for diesel engines aiming at... more Alternative fuels need to satisfy the strict requirements of the use for diesel engines aiming at enhancing the performance and reducing pollutant emissions. The use of straight bio-oils for diesel engines entails improving their disadvantages such as high density, high surface tension and kinematic viscosity (tri-physical parameters). There have been some as-used methods for reduction of the above-mentioned negative effects related to straight bio-oil disadvantage, however, the adequately-heating method may be considered as a simple one helping the physical parameters of straight bio-oils to reach stable and highly-confident values which are close to those of traditional diesel fuel. As a consequence, the spray and atomization, combustion, performance, and emissions of diesel engines fueled with preheated bio-oils are improved. In this work, a study of the dependence of the density, surface tension and kinematic viscosity of coconut oil (a type of bio-oils) on temperatures (from 40-110 o C) within a wide variety are conducted. In the first stage, the influence study of temperature on tri-physical parameters is carried out on the basis of experimental correlation and asdescribed mathematical equation. In the second stage, the influence study of tri-physical parameters on spray and atomization parameters including penetration length (L b) and Sauter mean diameter (SMD), and the influence of tri-physical parameters on fuel supply system are investigated. The optimal range of temperature for the as-used bio-oils is found after analyzing and evaluating the obtained results regarding the physical properties and spray characteristics, as well as compared with those of diesel fuel. The confident level over 95% from the regression correlation equation between the above-mentioned tri-physical parameters and temperature is presented. Additionally, the measured spray parameters, the calculated values of frictional head loss and fuel flow rate are thoroughly reported.

Antimicrobial Agents and Chemotherapy, 1999

In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolo... more In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolones, (trovafloxacin, sparfloxacin, clinafloxacin, levofloxacin, and ciprofloxacin) against Bacteroides fragilis ATCC 23745 were conducted. The times required to reduce the viable counts by 3 log units were as follows: clinafloxacin, 2.9 h; levofloxacin, 4.6 h; trovafloxacin, 6 h; and sparfloxacin, 10 h. Exposure to ciprofloxacin did not achieve a 3-log decrease in viable counts. The susceptibility of B. fragilis was determined both prior to exposure and following 24 h of exposure to each of the five fluoroquinolones tested. The MICs of clinafloxacin, levofloxacin, trovafloxacin, sparfloxacin, ciprofloxacin, metronidazole, cefoxitin, chloramphenicol, and clindamycin were determined by the broth microdilution method. The MICs for B. fragilis preexposure were as follows: clinafloxacin, 0.25 μg/ml; trovafloxacin, 0.5 μg/ml; sparfloxacin, 2 μg/ml; levofloxacin, 2 μg/ml; and ciprofloxacin, 8 μ...

Applied Thermal Engineering, 2017

Currently, atmospheric pollution and increased energy needs delineate the importance of alternate... more Currently, atmospheric pollution and increased energy needs delineate the importance of alternate sources of fuels. In this current study, the performance and emission characteristics of papaya seed methyl ester (PSME) blended with diesel are studied at varying loads. PSME is blended at 5, 10 and 15% into the fuel and, in addition to that, a 10% concentration of nbutanol is also blended. The blends showed promising results where the CO, HC and smoke emissions were reduced significantly by addition of n-butanol despite the higher viscosity of papaya seed oil. Also, the effect of n-butanol addition was high in blends with lower concentration of biodiesels. Their effect was found to be predominant at medium operating loads rather than at lower and higher loads. In addition to that, PSME increased the brake thermal efficiency (BTE), exhaust gas temperature (EGT) and NO x emissions.

Proceedings of the National Academy of Sciences, 2015

Significance Prostate cancer has an unpredictable natural history: While most tumors are clinical... more Significance Prostate cancer has an unpredictable natural history: While most tumors are clinically indolent, some patients display lethal phenotypes. Serum prostate-specific antigen is the most often used test in prostate cancer but screening is controversial. Treatment options are limited for metastatic disease, hence the need for early diagnosis. Prostate cancer antigen 3 ( PCA3 ), a long noncoding RNA, is the most specific biomarker identified and approved as a diagnostic test. However, its inherent biological function (if any) has remained elusive. We uncovered a negative transdominant oncogenic role for PCA3 that down-regulates an unrecognized tumor suppressor gene, PRUNE2 (a human homolog of the Drosophila prune gene) thereby promoting malignant cell growth. This work defines a unique biological function for PCA3 in prostate cancer.

International Journal of Science and Research (IJSR), 2016

An experimental analysis was carried out to investigate two types of non edible oils (Hazelnut an... more An experimental analysis was carried out to investigate two types of non edible oils (Hazelnut and Corn) blended with conventional diesel fuel approximately with proportions of 5%, 10 % , 15%, 20% and 25% by volume in a 4-stroke single cylinder, vertical, water cooled, Compression Ignition engine. Number of experimental trials were conducted with the above bio-diesel blends as fuel operated in the engine working at all loads from minimum to maximum. An analysis was made to compare the results such as exhaust emission characteristics like NOx emissions, CO emissions, smoke density, and total and partially unburned hydrocarbons. Performance parameters like brake specific fuel consumption(BSFC), brake Thermal efficiency(BTHE), and exhaust gas temperatures(EGT) for all blends prepared by blending the bio-diesels mentioned above with conventional diesel fuel separately with different proportions listed in the work. In this work CI engine is giving better performance with blend B20 for both diesels used as fuel when compare with remaining blends of both bio-diesels. But when compare with these B20 blends are showing marginal decrease in the performance parameters. Engine working with bio-diesel blends as fuel are showing noticeable reduction in exhaust emissions like carbon monoxides (CO), hydro carbons(HC) and slight increase in oxides of nitrogen(NOx) when compared with conventional neat diesel fuel.. Bio-diesel blend prepared from hazelnut bio-diesel showing better properties next to diesel fuel when compared with remaining bio-diesels used in the present work. This blend is showing better engine performance and decreased engine emissions when compared with Corn bio-diesel blends. After hazel nut oil immediately corn is giving better performance.

European heart journal, Jan 26, 2017

The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL... more The recent failures of HDL-raising therapies have underscored our incomplete understanding of HDL biology. Therefore there is an urgent need to comprehensively investigate HDL metabolism to enable the development of effective HDL-centric therapies. To identify novel regulators of HDL metabolism, we performed a joint analysis of human genetic, transcriptomic, and plasma HDL-cholesterol (HDL-C) concentration data and identified a novel association between trafficking protein, kinesin binding 2 (TRAK2) and HDL-C concentration. Here we characterize the molecular basis of the novel association between TRAK2 and HDL-cholesterol concentration. Analysis of lymphocyte transcriptomic data together with plasma HDL from the San Antonio Family Heart Study (n = 1240) revealed a significant negative correlation between TRAK2 mRNA levels and HDL-C concentration, HDL particle diameter and HDL subspecies heterogeneity. TRAK2 siRNA-mediated knockdown significantly increased cholesterol efflux to apoli...

Journal of Visualized Experiments, 2012

Cholesterol content of cells must be maintained within the very tight limits, too much or too lit... more Cholesterol content of cells must be maintained within the very tight limits, too much or too little cholesterol in a cell results in disruption of cellular membranes, apoptosis and necrosis 1. Cells can source cholesterol from intracellular synthesis and from plasma lipoproteins, both sources are sufficient to fully satisfy cells' requirements for cholesterol. The processes of cholesterol synthesis and uptake are tightly regulated and deficiencies of cholesterol are rare 2. Excessive cholesterol is more common problem 3. With the exception of hepatocytes and to some degree adrenocortical cells, cells are unable to degrade cholesterol. Cells have two options to reduce their cholesterol content: to convert cholesterol into cholesteryl esters, an option with limited capacity as overloading cells with cholesteryl esters is also toxic, and cholesterol efflux, an option with potentially unlimited capacity. Cholesterol efflux is a specific process that is regulated by a number of intracellular transporters, such as ATP binding cassette transporter proteins A1 (ABCA1) and G1 (ABCG1) and scavenger receptor type B1. The natural acceptor of cholesterol in plasma is high density lipoprotein (HDL) and apolipoprotein A-I. The cholesterol efflux assay is designed to quantitate the rate of cholesterol efflux from cultured cells. It measures the capacity of cells to maintain cholesterol efflux and/or the capacity of plasma acceptors to accept cholesterol released from cells. The assay consists of the following steps. Step 1: labelling cellular cholesterol by adding labelled cholesterol to serum-containing medium and incubating with cells for 24-48 h. This step may be combined with loading of cells with cholesterol. Step 2: incubation of cells in serum-free medium to equilibrate labelled cholesterol among all intracellular cholesterol pools. This stage may be combined with activation of cellular cholesterol transporters. Step 3: incubation of cells with extracellular acceptor and quantitation of movement of labelled cholesterol from cells to the acceptor. If cholesterol precursors were used to label newly synthesized cholesterol, a fourth step, purification of cholesterol, may be required. The assay delivers the following information: (i) how a particular treatment (a mutation, a knock-down, an overexpression or a treatment) affects the capacity of cell to efflux cholesterol and (ii) how the capacity of plasma acceptors to accept cholesterol is affected by a disease or a treatment. This method is often used in context of cardiovascular research, metabolic and neurodegenerative disorders, infectious and reproductive diseases.

Journal of Pharmacology and Experimental Therapeutics, 2012

Raising high-density lipoprotein (HDL) levels is proposed as an attractive target to treat cardio... more Raising high-density lipoprotein (HDL) levels is proposed as an attractive target to treat cardiovascular disease. However, a number of clinical studies examining the effect of HDL-raising therapies have been prematurely halted due to futility. Therefore there is a need for alternative therapies. Infusion of reconstituted HDL (rHDL) particles is still considered as a viable approach to increasing HDL levels. In this study we have profiled the antiinflammatory effects of a trimeric-HDL particle. We show that trimeric apoA-I and rHDL particles promote cholesterol efflux to a similar rate as native apoA-I particles in both ABCA1-dependent and-independent pathways. Trimeric particles inhibited ICAM-1 and VCAM-1 expression and the ability of the endothelium to capture monocytes under shear flow. Monocyte activation, CD11bdependent adhesion, and monocyte recruitment under shear flow conditions were perturbed by the trimeric particles. Our data suggest that trimeric rHDL particles can be constructed without any loss of function, preserving the anti-inflammatory effects of HDL that are key to its in vivo actions.

Journal of Lipid Research, 2004

This study was aimed at developing a method for high-efficiency transient transfection of macroph... more This study was aimed at developing a method for high-efficiency transient transfection of macrophages. Seven methods were evaluated for transient transfection of murine macrophage RAW 264.7 cells. The highest transfection efficiency was achieved with DEAE-dextran, although the proportion of cells expressing the reporter gene did not exceed 20%. It was subsequently found that the cytomegalovirus plasmid promoter in these cells becomes methylated. When cells were treated with the methylation inhibitor 5-azacytidine, methylation of the plasmid promoter was abolished and a dose-dependent stimulation of reporter gene expression was observed with expression achieved in more than 80% of cells. Treatment of cells with 5-azacytidine also caused increased efficiency of transfection of macrophages with plasmids driven by RSV, SV40, and EF-1 ␣ promoters and transient transfection of human HepG2 cells. Inhibition of methylation also increased the amount and activity of sterol 27-hydroxylase (CYP27A1) detected in RAW 264.7 cells transfected with a CYP27A1 expression plasmid. Treatment of cells with 5-azacytidine alone did not affect either cholesterol efflux from nontransfected cells or expression of ABCA1 and CYP27A1. However, transfection with CYP27A1 led to a 2-to 4-fold increase of cholesterol efflux. We conclude that treatment with 5-azacytidine can be used for high-efficiency transient transfection of macrophages.-Escher, G.

Journal of Lipid Research, 2002

Physical activity can raise the level of circulating HDL cholesterol. Pre ␤ 1-HDL is thought to b... more Physical activity can raise the level of circulating HDL cholesterol. Pre ␤ 1-HDL is thought to be either the initial acceptor of cellular cholesterol or virtually the first particle in the pathway of the formation of HDL from apolipoprotein A-I and cellular lipids. We have therefore sought to identify pre ␤ 1-HDL in arterial and venous circulations of exercising legs in healthy individuals and in subjects with stable Type 2 diabetes mellitus. Blood samples were taken simultaneously from the femoral artery and vein before and after 25 min cycling exercise. The major findings were, first, that exercise significantly increased plasma concentration of pre ␤ 1-HDL (20% increase, P Ͻ 0.05) and second, that the pre ␤ 1-HDL concentration was significantly higher in the venous compared with the arterial blood both before and after exercise in both diabetics and controls. In the combined population, formation of pre ␤ 1-HDL at rest was 9.9 ؎ 5.2 mg/min and exercise enhanced pre ␤ 1-HDL formation 6.6-fold in both groups.-Sviridov, D., B. Kingwell, A. Hoang, A. Dart, and P. Nestel. Single session exercise stimulates formation of pre ␤ 1-HDL in leg muscle.

The Journal of Clinical Endocrinology & Metabolism, 2008

Background: Low plasma concentration of high-density lipoprotein (HDL) cholesterol is a risk fact... more Background: Low plasma concentration of high-density lipoprotein (HDL) cholesterol is a risk factor for cardiovascular disease and a feature of the metabolic syndrome. Rosuvastatin has been shown to increase HDL cholesterol concentration, but the mechanisms remain unclear.Methods and Results: Twelve men with the metabolic syndrome were studied in a randomized, double-blind, crossover trial of 5-wk therapeutic periods with placebo, 10 mg/d rosuvastatin, or 40 mg/d rosuvastatin, with 2-wk placebo washout between each period. Compared with placebo, there was a significant dose-dependent increase in HDL cholesterol, HDL particle size, and concentration of HDL particles that contain apolipoprotein A-I (LpA-I). The increase in LpA-I concentration was associated with significant dose-dependent reductions in triglyceride concentration and LpA-I fractional catabolic rate, with no changes in LpA-I production rate. There was a significant dose-dependent reduction in the fractional catabolic ra...

Arteriosclerosis, Thrombosis, and Vascular Biology, 2008

Objective—Whereas the anti–inflammatory effects of high-density lipoprotein (HDL) on endothelial ... more Objective—Whereas the anti–inflammatory effects of high-density lipoprotein (HDL) on endothelial cells are well described, such effects on monocytes are less studied.Methods and Results—Human monocytes were isolated from whole blood followed by assessment of CD11b activation/expression and cell adhesion under shear-flow. HDL caused a dose-dependent reduction in the activation of CD11b induced by PMA or receptor-dependent agonists. The constituent of HDL responsible for the antiinflammatory effects on CD11b activation was found to be apolipoprotein A-I (apoA-I). Cyclodextrin, but not cyclodextrin/cholesterol complex, also inhibited PMA-induced CD11b activation implicating cholesterol efflux as the main mechanism. This was further confirmed with the demonstration that cholesterol content of lipid rafts diminished after treatment with the cholesterol acceptors. Blocking ABCA1 with an anti-ABCA1 antibody abolished the effect of apoA-I. Furthermore, monocytes derived from a Tangier disea...

Arteriosclerosis, Thrombosis, and Vascular Biology, 2004

Background— Physical exercise is associated with a decreased risk of cardiovascular disease, whic... more Background— Physical exercise is associated with a decreased risk of cardiovascular disease, which may be partly caused by the effect of exercise on the lipoprotein profile. The most consistent effect of exercise on lipoprotein metabolism is an increase in high-density lipoprotein (HDL). Methods and Results— Parameters of reverse cholesterol transport (RCT) in 25 endurance-trained male athletes were compared with 33 age-matched males enjoying an active lifestyle. V o 2 max was higher in athletes than in controls (53.4±1.2 versus 38.8±1.0 mL/min per kg; P <0.01). The following differences in parameters of RCT were found: (1) plasma HDL cholesterol and apoA-I levels were higher in athletes compared with controls (1.7±0.1 versus 1.4±0.1 mmol/L; P <0.001; and 145±2 versus 128±3 mg/dL; P <0.001, respectively). Both correlated with V o 2 max up to the value of 51 mL/min per kg; (2) preβ 1 -HDL was higher in athletes than in controls (54±4 versus 37±3 μg/mL; P <0.001) and corre...

Tạp chí Y Dược học Cần Thơ

Đặt vấn đề: Kháng sinh là một nhóm thuốc đặc biệt vì việc sử dụng kháng sinh không chỉ ảnh hưởng ... more Đặt vấn đề: Kháng sinh là một nhóm thuốc đặc biệt vì việc sử dụng kháng sinh không chỉ ảnh hưởng đến người bệnh mà còn ảnh hưởng đến cộng đồng. Ở Việt Nam, đây là một nhóm thuốc quan trọng vì bệnh lý nhiễm khuẩn nằm trong số những bệnh đứng hàng đầu cả về tỷ lệ mắc bệnh và tỷ lệ tử vong. MRSA chiếm 82,1 % trong tổng số các chủng S. aureus phân lập là nguyên nhân gây tử vong liên quan viêm phổi bệnh viện. Mục tiêu nghiên cứu: Xác định công thức hợp lực của các cao phân đoạn Trâm Tròn, Xăng Mã, Cò Ke trên hoạt tính kháng MRSA. Đối tượng và phương pháp nghiên cứu: Sử dụng phương pháp khuếch tán đĩa, phương pháp vi pha loãng để xác định hoạt tính kháng MRSA của cao ethanol toàn phần Trâm Tròn, Xăng Mã, Cò Ke và các cao phân đoạn, thử nghiệm SRB chứng minh tính an toàn của cao ethanol toàn phần thực vật trên hai dòng tế bào nguyên bào sợi và tế bào ung thư gan. Chỉ số FIC được tính toán dựa vào phương pháp bàn cờ, xác định khả năng hợp lực của các cao phân đoạn ethyl acetate với nhau trê...

Chemical engineering transactions, 2020

Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly spreading in hospitals. ... more Methicillin-resistant Staphylococcus aureus (MRSA) has been increasingly spreading in hospitals. The discovery of a new antibiotic is increasingly difficult due to its huge amount of time and money requirements. Medicinal herbs were used in the treatment of infectious diseases for a long time. Binh Duong province has a rich source of indigenous plants. Traditional remedies of these plants have been used in treating infectious diseases. However, there are very few studies on natural antibiotics in the area. The main purpose of this study is to investigate antibacterial activity of Syzygium glomerulatum collected in Binh Duong on methicillin-resistant Staphylococcus aureus. Agar disc diffusion and micro dilution methods were performed to determine antibacterial activity against MRSA of Syzygium glomerulatum and its ability to combine with vancomycin antibiotic. In addition, the cell toxicity of Syzygium glomerulatum was determined by SRB (Sulforhodamine B). Results showed that the min...

Urban Science, 2019

In Ho Chi Minh City (HCMC, Vietnam), there is now an urgent need for evaluating access to parks i... more In Ho Chi Minh City (HCMC, Vietnam), there is now an urgent need for evaluating access to parks in an effort to ensure better planning within the context of rapid and increasingly privatized urbanization. In this article, we analyze the provision and accessibility to parks in HCMC. To achieve this, the information gathered was then integrated into the geographical information systems (GISs). Based on an Ascending Hierarchical Classification, we were able to identify five different types ranging in their intrinsic characteristics. The accessibility measurements calculated in the GISs show that communities are located an average of at least 879 meters away from parks, which is a relatively short distance. Children have a level of accessibility comparable to that of the overall population. Accessibility also seems to vary greatly throughout the City—populations residing in central districts (planned before 1996) enjoy better accessibility compared to those in peripheral neighborhoods (...

Journal of Lipid Research, 2002

Five mutants of apolipoprotein A-I (apoA-I), apoA-I(Δ63–73), apoA-I(Δ140–150), apoA-I(63–73@140–1... more Five mutants of apolipoprotein A-I (apoA-I), apoA-I(Δ63–73), apoA-I(Δ140–150), apoA-I(63–73@140–150), apoA-I(R149V), and apoA-I(P143A) were compared with human plasma apoA-I for their ability to promote cholesterol and phospholipid efflux from HepG2 cells. A significantly lower capacity to promote cholesterol and phospholipid efflux was observed with lipid-free apoA-I(Δ63–73), while mutations apoA-I(Δ140–150) and apoA-I(P143A) affected phospholipid efflux only. When added as apoA-I/palmitoyloleoyl phosphatidylcholine (POPC) complex, mutations apoA-I(63–73@140–150) and apoA-I(Δ140–150) affected cholesterol efflux. None of the mutations affected α-helicity of the lipid-free mutants or their self-association. Five natural mutations of apoA-I, apoA-I(A95D), apoA-I (Y100H), apoA-I(E110K), apoA-I(V156E), and apoA-I (H162Q) were studied for their ability to bind lipids and promote cholesterol efflux. None of the mutations affected lipid-binding properties, cholesterol efflux, or α-helicity...

International Journal on Advanced Science, Engineering and Information Technology, 2019

Pollution in the maritime field is considered as such a serious problem that scientists, policyma... more Pollution in the maritime field is considered as such a serious problem that scientists, policymakers, and managers are always urged with a desire to find solutions and strategies one way or another to minimize its negative impacts on the environment and the life. Among the effective solutions, the use of fuels with limited-sulfur content or bio-based fuels has been paid much attention to due to their advantages in the use of marine diesel engines. In the current study, a type of fossil diesel fuel with ultra-low sulfur content (ULSD) was mixed with coconut oil (CO) through the ultrasonic treatment under the changes in volume fraction of as-used fuels, the correlation on viscosity selected the rate mixing between ULSD and coconut oil. After 12 minutes of ultrasound treatment, the highest stability of the ULSD-CO emulsion was achieved correspondingly to 97.8% for a mixing rate of 76%(ULSD):24%(CO) along with the distance of 85mm from the containing-vessel bottom to the ultrasound horn tip. Moreover, the spray characteristics including penetration length and a cone angle of ULSD, CO, and ULSD-CO emulsion were also examined and compared to diesel fuel. The similarity of spray characteristics to diesel fuel, containing ultra-low sulfur content and oxygen content, renewability are considered as some advantages of ULSD-CO emulsion as used for diesel engines aiming to meet the stricter requirements of IMO regulations about the strategies of environmental protection.

Biofuel Research Journal, 2019

HIGHLIGHTS Preheated and unpreheated straight Jatropha oil, and fossil diesel fuel were experime... more HIGHLIGHTS Preheated and unpreheated straight Jatropha oil, and fossil diesel fuel were experimentally compared. Spray characteristics, i.e., cone angle and penetration length were investigated. Thermal efficiency and emission parameters were tested at 0 h and after 300 h of engine operation. Trilateral correlation of spray characteristics, combustion parameters, and deposit accumulation in injector orifices was analyzed. Unpreheated straight Jatropha oil cannot be recommended for long term use in diesel engines.

International Journal on Advanced Science, Engineering and Information Technology, 2018

Alternative fuels need to satisfy the strict requirements of the use for diesel engines aiming at... more Alternative fuels need to satisfy the strict requirements of the use for diesel engines aiming at enhancing the performance and reducing pollutant emissions. The use of straight bio-oils for diesel engines entails improving their disadvantages such as high density, high surface tension and kinematic viscosity (tri-physical parameters). There have been some as-used methods for reduction of the above-mentioned negative effects related to straight bio-oil disadvantage, however, the adequately-heating method may be considered as a simple one helping the physical parameters of straight bio-oils to reach stable and highly-confident values which are close to those of traditional diesel fuel. As a consequence, the spray and atomization, combustion, performance, and emissions of diesel engines fueled with preheated bio-oils are improved. In this work, a study of the dependence of the density, surface tension and kinematic viscosity of coconut oil (a type of bio-oils) on temperatures (from 40-110 o C) within a wide variety are conducted. In the first stage, the influence study of temperature on tri-physical parameters is carried out on the basis of experimental correlation and asdescribed mathematical equation. In the second stage, the influence study of tri-physical parameters on spray and atomization parameters including penetration length (L b) and Sauter mean diameter (SMD), and the influence of tri-physical parameters on fuel supply system are investigated. The optimal range of temperature for the as-used bio-oils is found after analyzing and evaluating the obtained results regarding the physical properties and spray characteristics, as well as compared with those of diesel fuel. The confident level over 95% from the regression correlation equation between the above-mentioned tri-physical parameters and temperature is presented. Additionally, the measured spray parameters, the calculated values of frictional head loss and fuel flow rate are thoroughly reported.

Antimicrobial Agents and Chemotherapy, 1999

In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolo... more In vitro pharmacodynamic studies investigating the antimicrobial properties of five fluoroquinolones, (trovafloxacin, sparfloxacin, clinafloxacin, levofloxacin, and ciprofloxacin) against Bacteroides fragilis ATCC 23745 were conducted. The times required to reduce the viable counts by 3 log units were as follows: clinafloxacin, 2.9 h; levofloxacin, 4.6 h; trovafloxacin, 6 h; and sparfloxacin, 10 h. Exposure to ciprofloxacin did not achieve a 3-log decrease in viable counts. The susceptibility of B. fragilis was determined both prior to exposure and following 24 h of exposure to each of the five fluoroquinolones tested. The MICs of clinafloxacin, levofloxacin, trovafloxacin, sparfloxacin, ciprofloxacin, metronidazole, cefoxitin, chloramphenicol, and clindamycin were determined by the broth microdilution method. The MICs for B. fragilis preexposure were as follows: clinafloxacin, 0.25 μg/ml; trovafloxacin, 0.5 μg/ml; sparfloxacin, 2 μg/ml; levofloxacin, 2 μg/ml; and ciprofloxacin, 8 μ...

Applied Thermal Engineering, 2017

Currently, atmospheric pollution and increased energy needs delineate the importance of alternate... more Currently, atmospheric pollution and increased energy needs delineate the importance of alternate sources of fuels. In this current study, the performance and emission characteristics of papaya seed methyl ester (PSME) blended with diesel are studied at varying loads. PSME is blended at 5, 10 and 15% into the fuel and, in addition to that, a 10% concentration of nbutanol is also blended. The blends showed promising results where the CO, HC and smoke emissions were reduced significantly by addition of n-butanol despite the higher viscosity of papaya seed oil. Also, the effect of n-butanol addition was high in blends with lower concentration of biodiesels. Their effect was found to be predominant at medium operating loads rather than at lower and higher loads. In addition to that, PSME increased the brake thermal efficiency (BTE), exhaust gas temperature (EGT) and NO x emissions.

Proceedings of the National Academy of Sciences, 2015

Significance Prostate cancer has an unpredictable natural history: While most tumors are clinical... more Significance Prostate cancer has an unpredictable natural history: While most tumors are clinically indolent, some patients display lethal phenotypes. Serum prostate-specific antigen is the most often used test in prostate cancer but screening is controversial. Treatment options are limited for metastatic disease, hence the need for early diagnosis. Prostate cancer antigen 3 ( PCA3 ), a long noncoding RNA, is the most specific biomarker identified and approved as a diagnostic test. However, its inherent biological function (if any) has remained elusive. We uncovered a negative transdominant oncogenic role for PCA3 that down-regulates an unrecognized tumor suppressor gene, PRUNE2 (a human homolog of the Drosophila prune gene) thereby promoting malignant cell growth. This work defines a unique biological function for PCA3 in prostate cancer.