Publications by authors named "Thao Phan"

12 Publications

  • Page 1 of 1

Green Tea Extract Enhances the Oxidative Stability of DHA-Rich Oil.

Antioxidants (Basel) 2021 Jun 19;10(6). Epub 2021 Jun 19.

Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, L7.07.03, B-1348 Louvain-la-Neuve, Belgium.

Docosahexaenoic acid (DHA) is one of the most important omega-3 polyunsaturated fatty acids, with proven health-promoting properties. However, oils with a very high content in DHA (DHAO) are extremely susceptible to oxidation, which affects shelf stability and limits incorporation in food products. Green tea extracts (GTE) are potential candidates for the protection of these oils, but their use in such oils has not been previously reported. This study investigated the effect of GTE (160 ppm, 400 ppm, 1000 ppm) and α-tocopherol (80 ppm, 200 ppm, 500 ppm) on the oxidative stability of a DHAO over a 9-week storage at 30 °C. The oxidative status was monitored during storage by the measurement of peroxide value (PV) and -anisidine value (-AV). Changes in eicosapentaenoic acid (EPA) and DHA content, as well as in catechins and tocopherol contents, were also evaluated. The addition of GTE enhanced the oxidative stability of DHAO by reducing the formation of peroxides and secondary oxidation products, whereas α-tocopherol had no significant effect on the PV of oil during storage but led to a significantly higher -AV. The EPA and DHA content of DHAO was stable in GTE-supplemented samples whereas a decrease was observed in the control and α-tocopherol-supplemented samples. GTE also delayed the degradation of tocopherols initially present in the oil, while catechins resulting from the addition of GTE decreased progressively during the storage period.
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http://dx.doi.org/10.3390/antiox10060982DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8235633PMC
June 2021

Development of a Cell Suspension Culture System for Promoting Alkaloid and Vinca Alkaloid Biosynthesis Using Endophytic Fungi Isolated from Local .

Plants (Basel) 2021 Mar 31;10(4). Epub 2021 Mar 31.

Institute of Biotechnology, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi 100000, Vietnam.

Cell and tissue cultures of have been studied extensively as an alternative strategy to improve the production of valuable secondary metabolites. The purpose of this study was to produce callus and suspension cell biomass of good quality and quantity to improve the total alkaloids and bis-indole alkaloids. The young stem derived-callus of variety Quang Ninh (QN) was grown on MS medium supplemented with 1.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) plus 1.5 mg/L kinetin, and the growth rate increased by 67-fold after 20 days. The optimal conditions for maintaining the cell suspension culture were 150 mg/50 mL cell inoculum, a medium pH of 5.5 and a culture temperature of 25 °C. The low alkaloid content in the culture was compensated for by using endophytic fungi isolated from local . Cell extracts of endophytic fungi-identified as RN1 and RN3-were found to significantly promote alkaloid accumulation. This elicitation also stimulated the accumulation of a tested bis-indole alkaloid, vinblastine. The findings are important for investigating the effects of fungal elicitors on the biosynthesis of vinblastine and vincristine, as well as other terpenoid indole alkaloids (TIAs), in QN cell suspension cultures.
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http://dx.doi.org/10.3390/plants10040672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066771PMC
March 2021

Centrosome defects cause microcephaly by activating the 53BP1-USP28-TP53 mitotic surveillance pathway.

EMBO J 2021 01 23;40(1):e106118. Epub 2020 Nov 23.

Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Mutations in centrosome genes deplete neural progenitor cells (NPCs) during brain development, causing microcephaly. While NPC attrition is linked to TP53-mediated cell death in several microcephaly models, how TP53 is activated remains unclear. In cultured cells, mitotic delays resulting from centrosome loss prevent the growth of unfit daughter cells by activating a pathway involving 53BP1, USP28, and TP53, termed the mitotic surveillance pathway. Whether this pathway is active in the developing brain is unknown. Here, we show that the depletion of centrosome proteins in NPCs prolongs mitosis and increases TP53-mediated apoptosis. Cell death after a delayed mitosis was rescued by inactivation of the mitotic surveillance pathway. Moreover, 53BP1 or USP28 deletion restored NPC proliferation and brain size without correcting the upstream centrosome defects or extended mitosis. By contrast, microcephaly caused by the loss of the non-centrosomal protein SMC5 is also TP53-dependent but is not rescued by loss of 53BP1 or USP28. Thus, we propose that mutations in centrosome genes cause microcephaly by delaying mitosis and pathologically activating the mitotic surveillance pathway in the developing brain.
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http://dx.doi.org/10.15252/embj.2020106118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780150PMC
January 2021

Targeting TRIM37-driven centrosome dysfunction in 17q23-amplified breast cancer.

Nature 2020 09 9;585(7825):447-452. Epub 2020 Sep 9.

Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Genomic instability is a hallmark of cancer, and has a central role in the initiation and development of breast cancer. The success of poly-ADP ribose polymerase inhibitors in the treatment of breast cancers that are deficient in homologous recombination exemplifies the utility of synthetically lethal genetic interactions in the treatment of breast cancers that are driven by genomic instability. Given that defects in homologous recombination are present in only a subset of breast cancers, there is a need to identify additional driver mechanisms for genomic instability and targeted strategies to exploit these defects in the treatment of cancer. Here we show that centrosome depletion induces synthetic lethality in cancer cells that contain the 17q23 amplicon, a recurrent copy number aberration that defines about 9% of all primary breast cancer tumours and is associated with high levels of genomic instability. Specifically, inhibition of polo-like kinase 4 (PLK4) using small molecules leads to centrosome depletion, which triggers mitotic catastrophe in cells that exhibit amplicon-directed overexpression of TRIM37. To explain this effect, we identify TRIM37 as a negative regulator of centrosomal pericentriolar material. In 17q23-amplified cells that lack centrosomes, increased levels of TRIM37 block the formation of foci that comprise pericentriolar material-these foci are structures with a microtubule-nucleating capacity that are required for successful cell division in the absence of centrosomes. Finally, we find that the overexpression of TRIM37 causes genomic instability by delaying centrosome maturation and separation at mitotic entry, and thereby increases the frequency of mitotic errors. Collectively, these findings highlight TRIM37-dependent genomic instability as a putative driver event in 17q23-amplified breast cancer and provide a rationale for the use of centrosome-targeting therapeutic agents in treating these cancers.
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http://dx.doi.org/10.1038/s41586-020-2690-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597367PMC
September 2020

PKCε Inhibits Neuronal Dendritic Spine Development through Dual Phosphorylation of Ephexin5.

Cell Rep 2018 11;25(9):2470-2483.e8

Department of Biological Chemistry, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA. Electronic address:

Protein kinase C (PKC)-dependent mechanisms promote synaptic function in the mature brain. However, the roles of PKC signaling during synapse development remain largely unknown. Investigating each brain-enriched PKC isoform in early neuronal development, we show that PKCε acutely and specifically reduces the number of dendritic spines, sites of eventual synapse formation on developing dendrites. This PKCε-mediated spine suppression is temporally restricted to immature neurons and mediated through the phosphorylation and activation of Ephexin5, a RhoA guanine nucleotide exchange factor (GEF) and inhibitor of hippocampal synapse formation. Our data suggest that PKCε acts as an early developmental inhibitor of dendritic spine formation, in contrast to its emerging pro-synaptic roles in mature brain function. Moreover, we identify a substrate of PKCε, Ephexin5, whose early-elevated expression in developing neurons may in part explain the mechanism by which PKCε plays seemingly opposing roles that depend on neuronal maturity.
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http://dx.doi.org/10.1016/j.celrep.2018.11.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6371982PMC
November 2018

Current and future economic burden of diabetes among working-age adults in Asia: conservative estimates for Singapore from 2010-2050.

BMC Public Health 2016 Feb 16;16:153. Epub 2016 Feb 16.

Department of Pharmacy, National University of Singapore, Singapore, Singapore.

Background: Diabetes not only imposes a huge health burden but also a large economic burden worldwide. In the working-age population, cost of lost productivity can far exceed diabetes-related medical cost. In this study, we aimed to estimate the current and future indirect and excess direct costs of diagnosed type 2 diabetes among the working-age population in Singapore.

Methods: A previously-published epidemiological model of diabetes was adapted to forecast prevalence among working-age patients with diagnosed type 2 diabetes in the absence of interventions. The current methodology of the American Diabetes Association was adopted to estimate the costs of diabetes for this population. Diabetes-related excess direct medical costs were obtained from a local cost study while indirect costs were calculated using the human capital approach applied to local labor force statistics. These cost were estimated conservatively from a societal perspective on a per patient basis and projected to the overall Singapore population from 2010 to 2050.

Results: In 2010, total economic costs per working-age patient were estimated to be US$5,646 (US$4,432-US$10,612), of which 42% were excess direct medical costs and 58% indirect productivity-related losses. Total cost is projected to rise to US$7,791 (US$5,741-US$12,756) in 2050, with the share of indirect costs rising to 65%. Simultaneous increases in prevalence imply that the total economic costs of diabetes for the entire working-age population will increase by 2.4 fold from US$787 million in 2010 to US$1,867 million in 2050.

Conclusions: By current projections, diabetes in Singapore represents a growing economic burden. Among the working-age population, the impact of productivity loss will become increasingly significant. Prevention efforts to reduce overall prevalence should also engage stakeholders outside the health sector who ultimately bear the indirect burden of disease.
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http://dx.doi.org/10.1186/s12889-016-2827-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4754926PMC
February 2016

Forecasting the burden of type 2 diabetes in Singapore using a demographic epidemiological model of Singapore.

BMJ Open Diabetes Res Care 2014 11;2(1):e000012. Epub 2014 Jun 11.

Saw Swee Hock School of Public Health, National University of Singapore and National University Health System , Singapore ; Department of Statistics and Applied Probability , Faculty of Science, National University of Singapore , Singapore ; Program in Health Services and Systems Research, Duke-NUS Graduate Medical School , Singapore ; Yale-NUS College , Singapore.

Objective: Singapore is a microcosm of Asia as a whole, and its rapidly ageing, increasingly sedentary population heralds the chronic health problems other Asian countries are starting to face and will likely face in the decades ahead. Forecasting the changing burden of chronic diseases such as type 2 diabetes in Singapore is vital to plan the resources needed and motivate preventive efforts.

Methods: This paper describes an individual-level simulation model that uses evidence synthesis from multiple data streams-national statistics, national health surveys, and four cohort studies, and known risk factors-aging, obesity, ethnicity, and genetics-to forecast the prevalence of type 2 diabetes in Singapore. This comprises submodels for mortality, fertility, migration, body mass index trajectories, genetics, and workforce participation, parameterized using Markov chain Monte Carlo methods, and permits forecasts by ethnicity and employment status.

Results: We forecast that the obesity prevalence will quadruple from 4.3% in 1990 to 15.9% in 2050, while the prevalence of type 2 diabetes (diagnosed and undiagnosed) among Singapore adults aged 18-69 will double from 7.3% in 1990 to 15% in 2050, that ethnic Indians and Malays will bear a disproportionate burden compared with the Chinese majority, and that the number of patients with diabetes in the workforce will grow markedly.

Conclusions: If the recent rise in obesity prevalence continues, the lifetime risk of type 2 diabetes in Singapore will be one in two by 2050 with concomitant implications for greater healthcare expenditure, productivity losses, and the targeting of health promotion programmes.
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http://dx.doi.org/10.1136/bmjdrc-2013-000012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4212579PMC
December 2014

Improving HIV/AIDS Knowledge Management Using EHRs.

Online J Public Health Inform 2012 19;4(3). Epub 2012 Dec 19.

School of Information, The University of Texas at Austin.

Background: A primary goal for the development of EHRs and EHR-related technologies should be to facilitate greater knowledge management for improving individual and community health outcomes associated with HIV / AIDS. Most of the current developments of EHR have focused on providing data for research, patient care and prioritization of healthcare provider resources in other areas. More attention should be paid to using information from EHRs to assist local, state, national, and international entities engaged in HIV / AIDS care, research and prevention strategies. Unfortunately the technology and standards for HIV-specific reporting modules are still being developed.

Methods: A literature search and review supplemented by the author's own experiences with electronic health records and HIV / AIDS prevention strategies will be used. This data was used to identify both opportunities and challenges for improving public health informatics primarily through the use of latest innovations in EHRs. Qualitative analysis and suggestions are offered for how EHRs can support knowledge management and prevention strategies associated with HIV infection.

Results: EHR information, including demographics, medical history, medication and allergies, immunization status, and other vital statistics can help public health practitioners to more quickly identify at-risk populations or environments; allocate scarce resources in the most efficient way; share information about successful, evidenced-based prevention strategies; and increase longevity and quality of life.

Conclusion: Local, state, and federal entities need to work more collaboratively with NGOs, community-based organizations, and the private sector to eliminate barriers to implementation including cost, interoperability, accessibility, and information security.
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http://dx.doi.org/10.5210/ojphi.v4i3.4267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3615825PMC
April 2013

Molecular epidemiology of rabies virus in Vietnam (2006-2009).

Jpn J Infect Dis 2011 ;64(5):391-6

Department of Virology, National Institute of Hygiene and Epidemiology, Hanoi, Vietnam. nkanhhp@yahoo.com

This study was aimed at determining the molecular epidemiology of rabies virus (RABV) circulating in Vietnam. Intra vitam samples (saliva and cerebrospinal fluid) were collected from 31 patients who were believed to have rabies and were admitted to hospitals in northern provinces of Vietnam. Brain samples were collected from 176 sick or furious rabid dogs from all over the country. The human and canine samples were subjected to reverse transcription-polymerase chain reaction analysis. The findings showed that 23 patients tested positive for RABV. Interestingly, 5 rabies patients did not have any history of dog or cat bites, but they had an experience of butchering dogs or cats, or consuming their meat. RABV was also detected in 2 of the 100 sick dogs from slaughterhouses. Molecular epidemiological analysis of 27 RABV strains showed that these viruses could be classified into two groups. The RABVs classified into Group 1 were distributed throughout Vietnam and had sequence similarity with the strains from China, Thailand, Malaysia, and the Philippines. However, the RABVs classified into Group 2 were only found in the northern provinces of Vietnam and showed high sequence similarity with the strain from southern China. This finding suggested the recent influx of Group 2 RABVs between Vietnam and China across the border. Although the incidence of rabies due to circulating RABVs in slaughterhouses is less common than that due to dog bite, the national program for rabies control and prevention in Vietnam should include monitoring of the health of dogs meant for human consumption and vaccination for workers at dog slaughterhouses. Further, monitoring of and research on the circulating RABVs in dog markets may help to determine the cause of rabies and control the spread of rabies in slaughterhouses in Vietnam.
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January 2012

Use of ovotransferrin as an antimicrobial in turkeys naturally infected with Chlamydia psittaci, avian metapneumovirus and Ornithobacterium rhinotracheale.

Vet Microbiol 2011 Dec 19;153(3-4):257-63. Epub 2011 May 19.

Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, BE-9000 Ghent, Belgium.

Respiratory pathogens are difficult to control in large-scale turkey production. This report describes a clinical trial of antimicrobial ovoTF aerosol on a large Belgian turkey farm. ovoTF was administered to reduce Chlamydia psittaci (C. psittaci) infections and to study the impact of this action on the occurrence of Ornithobacterium rhinotracheale (O. rhinotracheale) and avian metapneumovirus (aMPV) infections. Two subsequent broods were included; (i) a control brood receiving no ovoTF and (ii) an ovoTF brood receiving ovoTF aerosol (5mg/animal) at the age of 2 weeks, continuing daily for 12 days. Twenty-four one-day-old toms of the control and ovoTF brood were tagged and monitored for 15 weeks. The control brood experienced two periods of respiratory disease, the first (2-3 weeks of age) due to C. psittaci and the second (8-17 weeks of age) in the presence of C. psittaci, O. rhinotracheale and maybe aMPV. Extensive antibiotic treatment was needed in 2, 8 and 9 week-old toms. In the ovoTF brood, toms stayed healthy until the age of 9 weeks, whereafter respiratory disease occurred in the presence of C. psittaci, O rhinotracheale and aMPV. OvoTF administration: (i) reduced the amount of C. psittaci in the air as demonstrated by bioaerosol monitoring, (ii) prevented respiratory disease during the first half of the brood period, (iii) was associated with 46% reduction of mortality, and (iv) reduced the antibiotic cost. Our results justify additional clinical trials to explore the use of this innovative antimicrobial strategy for poultry.
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http://dx.doi.org/10.1016/j.vetmic.2011.05.016DOI Listing
December 2011

Ecological factors associated with dengue fever in a Central Highlands province, Vietnam.

BMC Infect Dis 2011 Jun 16;11:172. Epub 2011 Jun 16.

Institute of Hygiene and Epidemiology of Tay Nguyen, Dak Lak, Vietnam.

Background: Dengue is a leading cause of severe illness and hospitalization in Vietnam. This study sought to elucidate the linkage between climate factors, mosquito indices and dengue incidence.

Methods: Monthly data on dengue cases and mosquito larval indices were ascertained between 2004 and 2008 in the Dak Lak province (Vietnam). Temperature, sunshine, rainfall and humidity were also recorded as monthly averages. The association between these ecological factors and dengue was assessed by the Poisson regression model with adjustment for seasonality.

Results: During the study period, 3,502 cases of dengue fever were reported. Approximately 72% of cases were reported from July to October. After adjusting for seasonality, the incidence of dengue fever was significantly associated with the following factors: higher household index (risk ratio [RR]: 1.66; 95% confidence interval [CI]: 1.62-1.70 per 5% increase), higher container index (RR: 1.78; 95% CI: 1.73-1.83 per 5% increase), and higher Breteau index (RR: 1.57; 95% CI: 1.53-1.60 per 5 unit increase). The risk of dengue was also associated with elevated temperature (RR: 1.39; 95% CI: 1.25-1.55 per 2 °C increase), higher humidity (RR: 1.59; 95% CI: 1.51-1.67 per 5% increase), and higher rainfall (RR: 1.13; 95% CI: 1.21-1.74 per 50 mm increase). The risk of dengue was inversely associated with duration of sunshine, the number of dengue cases being lower as the sunshine increases (RR: 0.76; 95% CI: 0.73-0.79 per 50 hours increase).

Conclusions: These data suggest that indices of mosquito and climate factors are main determinants of dengue fever in Vietnam. This finding suggests that the global climate change will likely increase the burden of dengue fever infection in Vietnam, and that intensified surveillance and control of mosquito during high temperature and rainfall seasons may be an important strategy for containing the burden of dengue fever.
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http://dx.doi.org/10.1186/1471-2334-11-172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126728PMC
June 2011
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