Thu Ha Nguyen Thi - Academia.edu (original) (raw)

Papers by Thu Ha Nguyen Thi

PLOS One, 2008

Background: Drug resistant typhoid fever is a major clinical problem globally. Many of the first ... more Background: Drug resistant typhoid fever is a major clinical problem globally. Many of the first line antibiotics, including the older generation fluoroquinolones, ciprofloxacin and ofloxacin, are failing.

European Journal of Organic Chemistry, 2009

Four new neo-clerodane diterpenoids, barbatines A–D (1–4), have been isolated from the whole plan... more Four new neo-clerodane diterpenoids, barbatines A–D (1–4), have been isolated from the whole plant of Scutellariabarbata (Lamiaceae), along with the known scutebarbatine A (5), and their structures determined by spectral analysis, including mass spectrometry and 2D NMR spectroscopy. The absolute configurations of 2 and 5 were established from their CD spectra by using the exciton chirality rule. A biogenetic pathway for these compounds is proposed based on their structures. Barbatine A (1) and scutebarbatine A (5) showed a significant ability to protect cells against H2O2 with ED50 values of 16.8 and 5.0 μM, respectively.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Microbial Cell Factories, 2011

Background Two sets of overlapping genes, lacLMReu and lacLMAci, encoding heterodimeric β-galacto... more Background Two sets of overlapping genes, lacLMReu and lacLMAci, encoding heterodimeric β-galactosidases from Lactobacillus reuteri and Lactobacillus acidophilus, respectively, have previously been cloned and expressed using the pSIP vector system and Lactobacillus plantarum WCSF1 as host. Despite the high similarity between these lacLM genes and the use of identical cloning and expression strategies, strains harboring lacLMReu produced about twenty-fold more β-galactosidase than strains containing lacLMAci. Results In this study, the plasmid copy numbers (PCN) of expression vectors pEH9R (lacLMReu) and pEH9A (lacLMAci) as well as the transcription levels of both lacLM genes were compared using quantitative PCR methods. Analyses of parallel fermentations of L. plantarum harboring either pEH9R or pEH9A showed that the expression plasmids were present in similar copy numbers. However, transcript levels of lacLM from L. reuteri (pEH9R) were up to 18 times higher than those of lacLM from L. acidophilus (pEH9A). As a control, it was shown that the expression levels of regulatory genes involved in pheromone-induced promoter activation were similar in both strains. Conclusion The use of identical expression strategies for highly similar genes led to very different mRNA levels. The data indicate that this difference is primarily caused by translational effects that are likely to affect both mRNA synthesis rates and mRNA stability. These translational effects thus seem to be a dominant determinant for the success of gene expression efforts in lactobacilli.

Carbohydrate Research, 2008

Galacto-oligosaccharides, complex mixtures of various sugars, are produced by transgalactosylatio... more Galacto-oligosaccharides, complex mixtures of various sugars, are produced by transgalactosylation from lactose using b-galactosidase and are of great interest for food and feed applications because of their prebiotic properties. Most galacto-oligosaccharide preparations currently available in the market contain a significant amount of monosaccharides and lactose. The mixture of galacto-oligosaccharides (GalOS) in this study produced from lactose using recombinant b-galactosidase from Lactobacillus reuteri contains 48% monosaccharides, 26.5% lactose and 25.5% GalOS. To remove efficiently both monosaccharides and lactose from this GalOS mixture containing significant amounts of prebiotic non-lactose disaccharides, a biocatalytic approach coupled with subsequent chromatographic steps was used. Lactose was first oxidised to lactobionic acid using fungal cellobiose dehydrogenases, and then lactobionic acid and monosaccharides were removed by ion-exchange and size-exclusion chromatography. Two different cellobiose dehydrogenases (CDH), originating from Sclerotium rolfsii and Myriococcum thermophilum, were compared with respect to their applicability for this process. CDH from S. rolfsii showed higher specificity for the substrate lactose, and only few other components of the GalOS mixture were oxidised during prolonged incubation. Since these sugars were only converted once lactose oxidation was almost complete, careful control of the CDH-catalysed reaction will significantly reduce the undesired oxidation, and hence subsequent removal, of any GalOS components. Removal of ions and monosaccharides by the chromatographic steps gave an essentially pure GalOS product, containing less than 0.3% lactose and monosaccharides, in a yield of 60.3%.

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1997

Severe malaria remains a major cause of mortality and morbidity for children living in many tropi... more Severe malaria remains a major cause of mortality and morbidity for children living in many tropical regions. With the emergence of strains of Plasmodium falciparum resistant to both chloroquine and quinine, alternative antimalarial agents are required. The artemisinin group of compounds are rapidly effective in severe disease when given by intramuscular or intravenous injection. However, these routes of administration are not always available in rural areas. In an open, randomized comparison 109 Vietnamese children, aged between 3 months and 14 years, with severeRfalciparum malaria, were allocated at random to receive artemisinin suppositories followed by mefloquine (n=37), intramuscular artesunate followed by mefloquine (n=37), or intravenous quinine followed by pyrimethamine/sulfadoxine (n=35).There were 9 deaths: 2 artemisinin, 4 artesunate and 5 quinine-treated children. There was no difference in fever clearance time, coma recovery, or length of hospital stay among the 3 groups. However, parasite clearance times were significantly faster in artemisinin and artesunate-treated patients than in those who received quinine (PCO.0001). Both artemisinin and artesunate were very well tolerated, but children receiving these drugs had lower peripheral reticulocyte counts by day 5 of treatment than those in the quinine group (-0.01 1). No other adverse effect or toxicity was found. There was no treatment failure in these 2 groups, but 4 patients in the quinine group failed to clear their parasites within 7 d of starting treatment and required alternative antimalarial therapy. Artemisinin suppositories are easy to administer, cheap, and very effective for treating children with severe malaria. In rural areas where medical facilities are lacking these drugs will allow antimalarial therapy to be instituted earlier in the course of the disease and may therefore save lives.

Journal of Physics: Conference Series, 2009

... Huynh Thi Ha1, Cao Tuan Anh2, Nguyen Thi Thu Ha1, Phan Viet Phong1, Dao Tran Cao1, Le Quang H... more ... Huynh Thi Ha1, Cao Tuan Anh2, Nguyen Thi Thu Ha1, Phan Viet Phong1, Dao Tran Cao1, Le Quang Huy1 and Nguyen The Quynh1 1 Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi, Vietnam 2 ...

Nephron Clinical Practice, 2008

The prevalence of chronic kidney disease (CKD) in Asia is expected to increase along with increas... more The prevalence of chronic kidney disease (CKD) in Asia is expected to increase along with increases of hypertension and diabetes. Most cases are not treated and progress to end-stage renal disease (ESRD) with an increased risk for cardiovascular complications. Renal replacement therapies are so expensive that most ESRD patients die without treatment. Thus, countermeasures against early stages of CKD are urgently needed. Nevertheless, basic information for CKD has not been reported in Vietnam. We conducted a survey of CKD in 8,505 inhabitants aged >40 years in Vietnam. Subjects with abnormal urinary findings were further examined, including serum creatinine levels. In this study, CKD was defined as…

Journal of Veterinary Medical Science, 2006

Blue eye disease'' is a viral infection of swine endemic in Mexico, which produces fatal encephal... more Blue eye disease'' is a viral infection of swine endemic in Mexico, which produces fatal encephalitis accompanied by respiratory signs and corneal opacity in suckling piglets. An atypical blue eye disease outbreak presented high rates of neurological signs in fattening and adult pigs from 2000 to 2003. In order to identify the basis of increased neurovirulence, the hemagglutinin-neuraminidase (HN) gene of several porcine rubulavirus isolates were sequenced and compared with that of La Piedad Michoacan virus and other isolates that did not produce neurological disorders in weaned pigs. Nine amino acid mutations distinguished the high neurovirulent PAC6-PAC9 viruses, whereas five mutations characterized the low neurovirulent PAC2 and PAC3 viruses. HN protein three-dimensional models showed that the main conformation and functional domains were preserved, although substitutions A 223 T and A 291 D occurred in PAC2 and PAC3 viruses, as well as A 511 K and E 514 K presented in PAC6-PAC9 viruses considerably modified the properties of the HN protein surface. The increased positive charge of the HN protein of PAC6-PAC9 viruses seems to be associated with their increased neurovirulence.

PLOS Neglected Tropical Diseases, 2011

gender. MCI participants spoke longer (p¼0.037) by 105 minutes on average per day during daily li... more gender. MCI participants spoke longer (p¼0.037) by 105 minutes on average per day during daily life than normal subjects in GEE models controlling for age, education, gender and living arrangement. Conclusions: MCI subjects may exhibit subtle language processing deficits that affect social cognitive abilities required for smooth social interactions, leading to more words spoken during conversations or longer daily talking time. The assessment approach used here may provide an ecologically valid behavioral marker sensitive to transitions to MCI.

Agricultural Systems, 2005

This study tests a method to identify and map the spatial distribution of general farming system ... more This study tests a method to identify and map the spatial distribution of general farming system types in five districts of the northern mountain region (NMR) of Vietnam. Over the last 50 years the NMR has suffered from a large loss of forest cover, often blamed on the swidden farming systems that are found in the mountains. As a result different programs have been put forward to change local land use practices: to decrease the amount of swidden land, ''sedentarize'' farmers responsible for practicing swidden agriculture, and introduce new farming systems. However, some researchers have identified one type of swidden farming system, composite swiddening, as ecologically more stable, causing little net deforestation and less environmental degradation than other farming systems in the NMR. To date no study has identified how widespread this or other types of farming systems are in the NMR. This study makes use of geographic data for five districts in the NMR within a GIS, combined with field checking, to characterize, identify and map the spatial distribution of the general farming system types, including composite swiddening, by commune for these districts. The results of the mapping indicate that there are few communes where a single farming system type is found. As these districts are spread over five provinces, the results reinforce the view that in VietnamÕs 0308-521X/$ -see front matter Ó (S.J. Leisz).

Căn cứ vào phương hướng nhiệm vụ năm học của trường THCS NGÔ QUYỀN, nay Tổ VĂN xây dựng kế hoạch ... more Căn cứ vào phương hướng nhiệm vụ năm học của trường THCS NGÔ QUYỀN, nay Tổ VĂN xây dựng kế hoạch hoạt động năm học 2012-2013 như sau: I/-ĐẶC ĐIỂM TÌNH HÌNH : 1) Tình hình đội ngũ giáo viên trong tổ: -Tổng số 13 / 12(nöõ) -Trình độ văn hóa 12/12: 10

PLOS One, 2008

Background: Drug resistant typhoid fever is a major clinical problem globally. Many of the first ... more Background: Drug resistant typhoid fever is a major clinical problem globally. Many of the first line antibiotics, including the older generation fluoroquinolones, ciprofloxacin and ofloxacin, are failing.

European Journal of Organic Chemistry, 2009

Four new neo-clerodane diterpenoids, barbatines A–D (1–4), have been isolated from the whole plan... more Four new neo-clerodane diterpenoids, barbatines A–D (1–4), have been isolated from the whole plant of Scutellariabarbata (Lamiaceae), along with the known scutebarbatine A (5), and their structures determined by spectral analysis, including mass spectrometry and 2D NMR spectroscopy. The absolute configurations of 2 and 5 were established from their CD spectra by using the exciton chirality rule. A biogenetic pathway for these compounds is proposed based on their structures. Barbatine A (1) and scutebarbatine A (5) showed a significant ability to protect cells against H2O2 with ED50 values of 16.8 and 5.0 μM, respectively.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Microbial Cell Factories, 2011

Background Two sets of overlapping genes, lacLMReu and lacLMAci, encoding heterodimeric β-galacto... more Background Two sets of overlapping genes, lacLMReu and lacLMAci, encoding heterodimeric β-galactosidases from Lactobacillus reuteri and Lactobacillus acidophilus, respectively, have previously been cloned and expressed using the pSIP vector system and Lactobacillus plantarum WCSF1 as host. Despite the high similarity between these lacLM genes and the use of identical cloning and expression strategies, strains harboring lacLMReu produced about twenty-fold more β-galactosidase than strains containing lacLMAci. Results In this study, the plasmid copy numbers (PCN) of expression vectors pEH9R (lacLMReu) and pEH9A (lacLMAci) as well as the transcription levels of both lacLM genes were compared using quantitative PCR methods. Analyses of parallel fermentations of L. plantarum harboring either pEH9R or pEH9A showed that the expression plasmids were present in similar copy numbers. However, transcript levels of lacLM from L. reuteri (pEH9R) were up to 18 times higher than those of lacLM from L. acidophilus (pEH9A). As a control, it was shown that the expression levels of regulatory genes involved in pheromone-induced promoter activation were similar in both strains. Conclusion The use of identical expression strategies for highly similar genes led to very different mRNA levels. The data indicate that this difference is primarily caused by translational effects that are likely to affect both mRNA synthesis rates and mRNA stability. These translational effects thus seem to be a dominant determinant for the success of gene expression efforts in lactobacilli.

Carbohydrate Research, 2008

Galacto-oligosaccharides, complex mixtures of various sugars, are produced by transgalactosylatio... more Galacto-oligosaccharides, complex mixtures of various sugars, are produced by transgalactosylation from lactose using b-galactosidase and are of great interest for food and feed applications because of their prebiotic properties. Most galacto-oligosaccharide preparations currently available in the market contain a significant amount of monosaccharides and lactose. The mixture of galacto-oligosaccharides (GalOS) in this study produced from lactose using recombinant b-galactosidase from Lactobacillus reuteri contains 48% monosaccharides, 26.5% lactose and 25.5% GalOS. To remove efficiently both monosaccharides and lactose from this GalOS mixture containing significant amounts of prebiotic non-lactose disaccharides, a biocatalytic approach coupled with subsequent chromatographic steps was used. Lactose was first oxidised to lactobionic acid using fungal cellobiose dehydrogenases, and then lactobionic acid and monosaccharides were removed by ion-exchange and size-exclusion chromatography. Two different cellobiose dehydrogenases (CDH), originating from Sclerotium rolfsii and Myriococcum thermophilum, were compared with respect to their applicability for this process. CDH from S. rolfsii showed higher specificity for the substrate lactose, and only few other components of the GalOS mixture were oxidised during prolonged incubation. Since these sugars were only converted once lactose oxidation was almost complete, careful control of the CDH-catalysed reaction will significantly reduce the undesired oxidation, and hence subsequent removal, of any GalOS components. Removal of ions and monosaccharides by the chromatographic steps gave an essentially pure GalOS product, containing less than 0.3% lactose and monosaccharides, in a yield of 60.3%.

Transactions of The Royal Society of Tropical Medicine and Hygiene, 1997

Severe malaria remains a major cause of mortality and morbidity for children living in many tropi... more Severe malaria remains a major cause of mortality and morbidity for children living in many tropical regions. With the emergence of strains of Plasmodium falciparum resistant to both chloroquine and quinine, alternative antimalarial agents are required. The artemisinin group of compounds are rapidly effective in severe disease when given by intramuscular or intravenous injection. However, these routes of administration are not always available in rural areas. In an open, randomized comparison 109 Vietnamese children, aged between 3 months and 14 years, with severeRfalciparum malaria, were allocated at random to receive artemisinin suppositories followed by mefloquine (n=37), intramuscular artesunate followed by mefloquine (n=37), or intravenous quinine followed by pyrimethamine/sulfadoxine (n=35).There were 9 deaths: 2 artemisinin, 4 artesunate and 5 quinine-treated children. There was no difference in fever clearance time, coma recovery, or length of hospital stay among the 3 groups. However, parasite clearance times were significantly faster in artemisinin and artesunate-treated patients than in those who received quinine (PCO.0001). Both artemisinin and artesunate were very well tolerated, but children receiving these drugs had lower peripheral reticulocyte counts by day 5 of treatment than those in the quinine group (-0.01 1). No other adverse effect or toxicity was found. There was no treatment failure in these 2 groups, but 4 patients in the quinine group failed to clear their parasites within 7 d of starting treatment and required alternative antimalarial therapy. Artemisinin suppositories are easy to administer, cheap, and very effective for treating children with severe malaria. In rural areas where medical facilities are lacking these drugs will allow antimalarial therapy to be instituted earlier in the course of the disease and may therefore save lives.

Journal of Physics: Conference Series, 2009

... Huynh Thi Ha1, Cao Tuan Anh2, Nguyen Thi Thu Ha1, Phan Viet Phong1, Dao Tran Cao1, Le Quang H... more ... Huynh Thi Ha1, Cao Tuan Anh2, Nguyen Thi Thu Ha1, Phan Viet Phong1, Dao Tran Cao1, Le Quang Huy1 and Nguyen The Quynh1 1 Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi, Vietnam 2 ...

Nephron Clinical Practice, 2008

The prevalence of chronic kidney disease (CKD) in Asia is expected to increase along with increas... more The prevalence of chronic kidney disease (CKD) in Asia is expected to increase along with increases of hypertension and diabetes. Most cases are not treated and progress to end-stage renal disease (ESRD) with an increased risk for cardiovascular complications. Renal replacement therapies are so expensive that most ESRD patients die without treatment. Thus, countermeasures against early stages of CKD are urgently needed. Nevertheless, basic information for CKD has not been reported in Vietnam. We conducted a survey of CKD in 8,505 inhabitants aged >40 years in Vietnam. Subjects with abnormal urinary findings were further examined, including serum creatinine levels. In this study, CKD was defined as…

Journal of Veterinary Medical Science, 2006

Blue eye disease'' is a viral infection of swine endemic in Mexico, which produces fatal encephal... more Blue eye disease'' is a viral infection of swine endemic in Mexico, which produces fatal encephalitis accompanied by respiratory signs and corneal opacity in suckling piglets. An atypical blue eye disease outbreak presented high rates of neurological signs in fattening and adult pigs from 2000 to 2003. In order to identify the basis of increased neurovirulence, the hemagglutinin-neuraminidase (HN) gene of several porcine rubulavirus isolates were sequenced and compared with that of La Piedad Michoacan virus and other isolates that did not produce neurological disorders in weaned pigs. Nine amino acid mutations distinguished the high neurovirulent PAC6-PAC9 viruses, whereas five mutations characterized the low neurovirulent PAC2 and PAC3 viruses. HN protein three-dimensional models showed that the main conformation and functional domains were preserved, although substitutions A 223 T and A 291 D occurred in PAC2 and PAC3 viruses, as well as A 511 K and E 514 K presented in PAC6-PAC9 viruses considerably modified the properties of the HN protein surface. The increased positive charge of the HN protein of PAC6-PAC9 viruses seems to be associated with their increased neurovirulence.

PLOS Neglected Tropical Diseases, 2011

gender. MCI participants spoke longer (p¼0.037) by 105 minutes on average per day during daily li... more gender. MCI participants spoke longer (p¼0.037) by 105 minutes on average per day during daily life than normal subjects in GEE models controlling for age, education, gender and living arrangement. Conclusions: MCI subjects may exhibit subtle language processing deficits that affect social cognitive abilities required for smooth social interactions, leading to more words spoken during conversations or longer daily talking time. The assessment approach used here may provide an ecologically valid behavioral marker sensitive to transitions to MCI.

Agricultural Systems, 2005

This study tests a method to identify and map the spatial distribution of general farming system ... more This study tests a method to identify and map the spatial distribution of general farming system types in five districts of the northern mountain region (NMR) of Vietnam. Over the last 50 years the NMR has suffered from a large loss of forest cover, often blamed on the swidden farming systems that are found in the mountains. As a result different programs have been put forward to change local land use practices: to decrease the amount of swidden land, ''sedentarize'' farmers responsible for practicing swidden agriculture, and introduce new farming systems. However, some researchers have identified one type of swidden farming system, composite swiddening, as ecologically more stable, causing little net deforestation and less environmental degradation than other farming systems in the NMR. To date no study has identified how widespread this or other types of farming systems are in the NMR. This study makes use of geographic data for five districts in the NMR within a GIS, combined with field checking, to characterize, identify and map the spatial distribution of the general farming system types, including composite swiddening, by commune for these districts. The results of the mapping indicate that there are few communes where a single farming system type is found. As these districts are spread over five provinces, the results reinforce the view that in VietnamÕs 0308-521X/$ -see front matter Ó (S.J. Leisz).

Căn cứ vào phương hướng nhiệm vụ năm học của trường THCS NGÔ QUYỀN, nay Tổ VĂN xây dựng kế hoạch ... more Căn cứ vào phương hướng nhiệm vụ năm học của trường THCS NGÔ QUYỀN, nay Tổ VĂN xây dựng kế hoạch hoạt động năm học 2012-2013 như sau: I/-ĐẶC ĐIỂM TÌNH HÌNH : 1) Tình hình đội ngũ giáo viên trong tổ: -Tổng số 13 / 12(nöõ) -Trình độ văn hóa 12/12: 10