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Tetrodotoxin analogues (TTXs) used in research and development were originated from biological sources for the last decades. Among TTXs‐bearing aquatic animals, horseshoe crab Carcinoscorpius rotundicauda from Vietnam's Coast was reported to contain a high level of TTXs, indicating a promising source for extraction and purification of TTXs. In this work, horseshoe crab C. rotundicauda collected from Can Gio Coast, Vietnam was used for TTX extraction using homogenization‐assisted method with acetic acid solvent. The extraction process was analysed and optimized by single‐factor investigation and response surface methodology (RSM). Single‐factor investigation pointed out that the optimal conditions for TTX recovery yield from C. rotundicauda's soft tissues were homogenization time of 20 min, acetic acid concentration of 1.0%, solvent/matrix ratio of 4 mL/g, extraction temperature of 70°C, extraction time of 30 min and number of extraction of two times. The most significant factors including acetic acid concentration, solvent/matrix ratio and extraction temperature were utilized for constructing the RSM model to predict TTX recovery yield. The maximal TTX recovery yield predicted from RSM model was 97.3% under solvent/matrix ratio of 4 mL/g, extraction temperature of 70°C and acetic acid concentration of 1% (v/v). The RSM model displayed a high stability and precision for prediction of TTX recovery yield from experiments of 1–10 kg C. rotundicauda's soft tissues/batch extractions producing low errors (−1.95% to 1.85%). TTXs in C. rotundicauda's soft tissues were elucidated by HPLC‐MS/MS, revealing the presence of three analogues TTX, 4epi‐TTX and Anh‐TTX with their contents of 43.02, 22.54 and 45.07 μg/g, respectively. [ABSTRACT FROM AUTHOR]

Chromolaena odorata (C. odorata) (L.) R. King & H. Robinson is a perennial flowering shrub with diverse habitats, including crops, grasslands, and roadsides. This plant has been widely used in Vietnamese folk medicine for gastric ulcer treatment. Hence, the present study aimed to evaluate the acute toxicity and the anti-ulcer effect of the ethanol crude extract of C. odorata leaves and its fractions against the indomethacin-induced gastric ulcer model in mice, and investigate the chemical constituents of the most active fraction. According to in vivo results, the ethyl acetate residue with the highest anti-ulcer activity significantly reduced gastric lesions in the experimental mice model with an ulcer index of 0.73 ± 0.39 and a percentage inhibition of 26.92%. Thus, this fraction was chosen for further chemical investigation. Four pure compounds (1-4) were extracted and isolated by using chromatographic methods. Based on the nuclear magnetic resonance spectroscopy, melting temperature, mass spectrometry analysis, and compared with the published literature, their structures were elucidated as 1-(4-hydroxy-3-methoxyphenyl)propane- 1,2-diol (1), kaempferol-7-O-α-L-rhamnopyranoside (2), naringenin-5,7-di-O-β-Dglucopyranoside (3), and rubrosterone (4). To our best knowledge, all of these compounds were isolated for the first time from C. odorata leaves. These findings contribute to providing scientific evidence for the traditional use and phytochemicals of C. odorata leaves. [ABSTRACT FROM AUTHOR]

Breast and gynaecological cancer (BGC) patients receiving chemotherapy may experience high levels of stress during the COVID-19 pandemic. Music interventions may be effective in lowering their stress levels. This study explored stressors, coping strategies, and the feasibility of music interventions among BGC patients in Vietnam. An exploratory qualitative study with individual face-to-face semi-structured interviews was conducted. A convenience sample of BGC patients receiving chemotherapy was recruited from the oncology centre of a public hospital in Vietnam. Twenty patients were interviewed with open-ended questions developed based on the transactional model of stress and coping to explore stress-causing factors and coping strategies and based on guidelines for music therapy practice to explore their music preferences and perceptions. Field notes and interview transcripts were analysed following the qualitative content analysis approach. Two stressor themes were identified: undesirable experiences during treatment and patients' inability to fulfil their own roles and responsibilities. Our findings revealed a new coping strategy—self-realisation of responsibilities towards the family—that is not listed in the transactional model of stress and coping. Future psychological interventions for stress management among BGC patients should focus on raising the patients' awareness of their values and responsibilities towards their families. Three categories of preferred music genres for stress reduction were identified: religious, softly melodic, and revolutionary music. The patients were aware of the positive effects of music and had different musical preferences. This study also explored the acceptance of music interventions and facilitators and barriers to implementing them among BGC patients in Vietnam. The findings suggest that before implementing music interventions, the musical preferences, religions, and beliefs of each individual should be considered to achieve desirable results. Music interventions for BGC patients receiving chemotherapy in Vietnam are feasible. Further intervention studies are needed to evaluate their effectiveness. [ABSTRACT FROM AUTHOR]

Ophiocordyceps is a megagenus of entomopathogenic fungi belonging to Ophiocordycipitaceae of Hypocreales, Ascomycota. We report here the morphological and phylogenetic analyses of two Ophiocordyceps species from Bidoup Nui Ba National Park, Lam Dong Province, southern Vietnam. Our data showed that one of our studied Ophiocordyceps is a new intraspecies of O. sphecocephala and another is a new record of O. asiana from Vietnam. [ABSTRACT FROM AUTHOR]

We investigate the key predictors that influence the soil organic matter (SOM) content in higher altitude plantations. This is to study the potential of carbon sequestration for recapturing CO2 from the atmosphere, which is an important consideration in mitigating global climate change. This research applied distance-based linear models to evaluate and predict the influence of topography and types of land use on soil carbon storage in the tropical mountainous areas of Central Vietnam. Three predictors plantation, altitude, and slope together explained 73.8% of the SOM variation. We focused on four types of plantations including acacia, rubber tree, cassava plantations, and plantations with rotation system between acacia and cassava. We found that they had different carbon accumulation, which depended on various characteristics of the terrain. The acacia plantation forest stored the highest amount of SOM and was less sensitive to changes in altitude. The soil carbon content in cassava plantations was the lowest, and altered considerably with altitude. SOM content in rubber tree and acacia-cassava rotation plantations were similar to each other. Altitude was the most critical driver in affecting the capacity of soil carbon sequestration in each plantation. In higher elevation zones, soil carbon stock was greater, which was probably related to decreasing decomposability by microorganism, and increasing carbon content in foliage and leaf litter. The carbon retention tended to increase gradually over an elevation range of 133–300 m a.s.l. The effects of the terrain slope were observed, when considering certain types of land use, and ones with small altitude disparity. In the slope range of 0° to 20°, the carbon pool showed a tendency to increase its capacity. Higher slope gradients, however, could hinder carbon retention due to organic material loss through erosion. In particular, when the slope was above 30°, the soil organic matter content decreased substantially. [ABSTRACT FROM AUTHOR]

Background: The efficacy of Helicobacter pylori (H. pylori) eradication therapy for children is currently low, and antibiotic resistance is a significant cause of treatment failure. The purpose of this study was to evaluate the H. pylori eradication efficacy of therapy based on antimicrobial susceptibility in pediatric patients with gastritis and peptic ulcer. Methods: This study was conducted at Can Tho Children's Hospital and Can Tho University of Medicine and Pharmacy Hospital between March 2019 and April 2022. We performed an upper gastrointestinal endoscopy, cultured H. pylori from biopsies of gastric mucosa, determined antibiotic sensitivities to H. pylori by the E-test method, and treated eradication based on the antibiotic susceptibilities of bacteria. After at least 4 weeks of eradication therapy, we assessed the effectiveness of treatment with a breath test. Results: Among 237 children recruited in this study, 48.9% were boys and 51.1% were girls, and the mean age was 10.03 ± 2.53 years. We determined that 80.6% of H. pylori were resistant to clarithromycin, as well as amoxicillin, metronidazole, levofloxacin, and tetracycline, at 71.7%, 49.4%, 45.1%, and 11.4%, respectively. The overall eradication rate of H. pylori was 83.1% (172/207). Among therapies tailored to antimicrobial susceptibility, the bismuth quadruple regimen achieved the greatest success, but the efficacy of triple therapy with esomeprazole + AMX + CLR/MTZ was low. Conclusions: Tailored eradication therapy was highly successful in our study but did not achieve over 90%. We recommend that in countries with a high prevalence of antibiotic resistance in H. pylori strains, particularly where the amoxicillin-resistance rate of H. pylori is high, therapy tailored to antimicrobial susceptibility should be used as first-line therapy, and bismuth and tetracycline should be added to enhance the eradication efficacy in children. [ABSTRACT FROM AUTHOR]

BMI, waist circumference (WC) and waist-to-height ratio (WHtR) can be used for discriminating children and adolescents at risk of CVD. However, consensus on how to use these anthropometric indicators is lacking for children and adolescents in Asia. Discrete criteria are promoted internationally, but continuous variables could be used. Data from a survey of 10 949 Vietnamese school-aged children (6–18 years) were used to evaluate the performance of anthropometric indicators to identify elevated blood pressure (BP), dyslipidaemia or at least three cardiovascular risk factors (CVRF). Weight, height, WC and BP were measured using standardised protocols; 1009 participants who had blood lipids were analysed. AUC was used to assess the performance, and the Youden index to identify optimal cut-offs. The prevalence of elevated BP, dyslipidaemia and CVRF was 26·5, 49·3 and 12·2 %, respectively. BMI, WC and WHtR had low capacity to identify elevated BP and dyslipidaemia (AUC range 0·61–0·66) but moderate capacity to identify CVRF (0·72–0·74). Optimal BMIZ cut-offs to identify elevated BP, dyslipidaemia and CVRF were 0·40, 1·01 and 1·1 sd ; for WC z -score, they were 0·06, 0·49 and 0·62 sd ; for WHtR, optimal cut-offs were close to 0·5. A BMIZ cut-off of 1·0 sd and a WHtR cut-off of 0·5 would, therefore, be useful criteria to identify Vietnamese children who are likely to have CVRF. However, further validation of these criteria in other studies of Asian children and adolescents is needed. [ABSTRACT FROM AUTHOR]

This study examines the impact of economic development, trade openness, and energy usage on Vietnam's CO2 emissions from 1985 to 2013 by applying an Auto-regression Distributed Lag (ARDL) model. The empirical results show a long-run relationship between economic development and CO2 emissions in Vietnam that can be expressed in an inverted U-curved function. Trade liberalization exhibits a positive impact on CO2 emissions, as a 1% increase in trade openness leads to a 0.191% increase in CO2 emissions for long-run elasticity. Furthermore, trade liberalisation has lag effects on CO2 emissions, which are estimated to reverse from negative to positive after a two year period. A 1% increase in energy usage leads to a 1.391% increase in CO2 emissions for long-run elasticity. Thus, environmental quality improves with cleaner technology and stricter regulations on environmental protection incorporated into international economics at the policy level in Vietnam. [ABSTRACT FROM AUTHOR]

This study demonstrated the prevalence of Porcine circovirus type 2 ( PCV2) among pig farms in Vietnam. Analyses of the genome, capsid protein and phylogeny classified all 30 Vietnamese PCV2 strains as the PCV2b genotype, belonging to the clusters of 1 A, 1 B, 1 C and recombinant forms. Each viral genome was 1767 nucleotides long and shared 96.0-100% nucleotide sequence identity. The amino acid substitutions in the capsid protein of the Vietnamese PCV2 strains were in immunodominant regions, and the majority of strains (24/30) contained a lysine extension at the C-terminus. Bayesian phylogeographic analysis revealed epidemic links of the PCV2 recombinant cluster within and among countries, which supports a circulating recombinant form of PCV2. Further analysis by the Jameson- Wolf antigenic index indicated antigenic alterations at important sites in the capsid protein (sites 131-133) among the recombinant cluster and the other clusters of PCV2b. [ABSTRACT FROM AUTHOR]

Purpose:Realizing the existence of information asymmetry in export markets and the use of signals to distinguish high-qualified sellers from low-qualified sellers, this study investigates the effects of signal consistency and signal clarity on exporter credibility, and subsequently, importer relationship intention. Methodology:Using a survey data set collected from a systematic sample of 418 Vietnamese importers, the authors tested a model hypothesizing the impact of signal consistency and signal clarity on exporter credibility, and subsequently, on importer relationship intention. Findings:The authors found that signal consistency and clarity have a positive impact on exporter credibility. Signal consistency also enhances the level of signal clarity. They also found that exporter credibility underlies importer relationship intension. Research Implications:Under the condition of information asymmetry, importers face difficulties in identifying and evaluating the best supplier among available suppliers in order to make the most appropriate selection decision. The findings confirm that signal clarity and consistency can help exporters to overcome such problems. Exporters should ensure that all signals sent to importers are clear and consistent over time to encourage importers to build long-term business relationships with them. Contributions:The findings of this study add to the literature on signaling in exporter–importer relationships and can serve as an initiation for further research in the area in transitioning economies. [ABSTRACT FROM AUTHOR]

Background: Prior to 2007, highly pathogenic avian influenza (HPAI) H5N1 viruses isolated from poultry and humans in Vietnam were consistently reported to be clade 1 viruses, susceptible to oseltamivir but resistant to amantadine. Here we describe the re-emergence of human HPAI H5N1 virus infections in Vietnam in 2007 and the characteristics of the isolated viruses. Methods and Findings: Respiratory specimens from patients suspected to be infected with avian influenza in 2007 were screened by influenza and H5 subtype specific polymerase chain reaction. Isolated H5N1 strains were further characterized by genome sequencing and drug susceptibility testing. Eleven poultry outbreak isolates from 2007 were included in the sequence analysis. Eight patients, all of them from northern Vietnam, were diagnosed with H5N1 in 2007 and five of them died. Phylogenetic analysis of H5N1 viruses isolated from humans and poultry in 2007 showed that clade 2.3.4 H5N1 viruses replaced clade 1 viruses in northern Vietnam. Four human H5N1 strains had eight-fold reduced in-vitro susceptibility to oseltamivir as compared to clade 1 viruses. In two poultry isolates the I117V mutation was found in the neuraminidase gene, which is associated with reduced susceptibility to oseltamivir. No mutations in the M2 gene conferring amantadine resistance were found. Conclusion: In 2007, H5N1 clade 2.3.4 viruses replaced clade 1 viruses in northern Vietnam and were susceptible to amantadine but showed reduced susceptibility to oseltamivir. Combination antiviral therapy with oseltamivir and amantadine for human cases in Vietnam is recommended. [ABSTRACT FROM AUTHOR]

Background: Inappropriate antibiotic use among outpatients is recognized as the primary driver of antibiotic resistance. A proper understanding of appropriate antibiotic usage and associated factors helps to determine and limit inappropriateness. We aimed to identify the rate of appropriate use of antibiotics and identify factors associated with the inappropriate prescriptions. Methods: We conducted a cross-sectional descriptive study in outpatient antibiotic use at a hospital in Can Tho City, Vietnam, from August 1, 2019, to January 31, 2020. Data were extracted from all outpatient prescriptions at the Medical Examination Department and analyzed by SPSS 18 and Chi-squared tests, with 95% confidence intervals. The rationale for antibiotic use was evaluated through antibiotic selection, dose, dosing frequency, dosing time, interactions between antibiotics and other drugs, and general appropriate usage. Results: A total of 420 prescriptions were 51.7% for females, 61.7% with health insurance, and 44.0% for patients with one comorbid condition. The general appropriate antibiotic usage rate was 86.7%. Prescriptions showed that 11.0% and 9.5% had a higher dosing frequency and dose than recommended, respectively; 10.2% had an inappropriate dosing time; 3.1% had drug interactions; and only 1.7% had been prescribed inappropriate antibiotics. The risk of inappropriate antibiotic use increased in patients with comorbidities and antibiotic treatment lasting >7 days (p < 0.05). Conclusions: The study indicated a need for more consideration when prescribing antibiotics to patients with comorbidities or using more than 7 days of treatment. [ABSTRACT FROM AUTHOR]

BACKGROUND Many studies have shown the effects of parental migration on the psychological and daily life of left-behind children (LBC) of labor migrant parents, but the results on schoolrelated problems of LBC remain inconsistent. Additionally, there is a dearth of research on the factors affecting school problems among LBC, especially in the socio-cultural context of Vietnam. The purpose of this study was to confirm the school problems encountered by LBC in comparison with non-left-behind children (non-LBC). The study also aimed to examine variables of bonding of caregivers with children and resilience of children affecting school problems of LBC. PARTICIPANTS AND PROCEDURE The convenient sampling approach was used in the study. The study sample included 792 Vietnamese school students (Mage = 12.65, SD = 1.60), with 439 children of labor migrant parents and a control group of 353 children of non-migrant parents. The School Problem Questionnaire, Parental Bonding Instrument and the Resilience Scale were employed in this study. RESULTS There was no difference in school problems between the LBC and non-LBC groups. Resilience by goal planning (RGP), resilience by affect control (RAC), and resilience by family support (RFS) were identified as protective variables for children to overcome difficulties encountered in schools, with regression coefficients of -.21, -.33 and -.20, respectively. Meanwhile, bonding of caregivers with children by control (BCCo), and resilience by positive thinking (RPT) were found to be factors that increase school problems among LBC with the same regression coefficient of .12. CONCLUSIONS Activities to support LBC should pay attention to improving resilience, namely affect control, goal planning, and promoting the role of caregivers for LBC. [ABSTRACT FROM AUTHOR]

background With the influence of Confucian culture, sex is often considered a taboo subject in Vietnam. This study aimed to examine the prevalence of exposure to sexually explicit Internet material (SEIM) among adolescents in Vietnam, as well as the factors affecting exposure to SEIM. participants and procedure The sample consisted of 886 Vietnamese adolescents (58.10% female) aged 15 to 18 years (M = 16.72, SD = 0.72). The survey was adapted from the study of Van Ouytsel, Ponnet and Walrave to assess the frequency of exposure to SEIM. Several measurement scales of factors affecting exposure to SEIM among adolescents were used including the Perceived Realism of SEIM, the Sexual Sensation Seeking Scale, the Family Cohesion and the Parental Monitoring Scale. results The overall prevalence of exposure to SEIM was 84.10%, with a gender difference: 89.80% in males and 80.00% in females. The prevalence of passive exposure to SEIM was 58.30%, higher than 41.70% for active exposure. Perceived realism of SEIM, sexual sensation seeking and Internet usage time for entertainment are factors affecting frequencies of exposure to SEIM among adolescents, with ß coefficient values of .29, .18 and .16 respectively. conclusions The majority of children in this study reported SEIM exposure. Parents, schools and other stakeholders should pay attention to sex education for children early on, diversifying forms and subjects of sex education. The content of sex education should emphasize the responsibility in the decisions made by children related to sex. [ABSTRACT FROM AUTHOR]

H2 thresholds for microbial respiration of arsenate (As(V)) were investigated in a pure culture of Sulfurospirillum arsenophilum. H2 was consumed to threshold concentrations of 0.03–0.09 nmol/L with As(V) as terminal electron acceptor, allowing for a Gibbs free-energy yield of 36–41 kJ per mol of reaction. These thresholds are among the lowest measured for anaerobic respirers and fall into the range of denitrifiers or Fe(III)-reducers. In sediments from an arsenic-contaminated aquifer in the Red River flood plain, Vietnam, H2 levels decreased to 0.4–2 nmol/L when As(V) was added under anoxic conditions. When As(V) was depleted, H2 concentrations rebounded by a factor of 10, a level similar to that observed in arsenic-free controls. The sediment-associated microbial population completely reduced millimolar levels of As(V)to arsenite (As(III)) within a few days. The rate of As(V)-reduction was essentially the same in sediments amended with a pure culture of S. arsenophilum. These findings together with a review of observed H2 threshold and steady-state values suggest that microbial As(V)-respirers have a competitive advantage over several other anaerobic respirers through their ability to thrive at low H2 levels. [ABSTRACT FROM AUTHOR]

In our antioxidant screening of some Vietnamese plant extracts, the CHCl 3 -soluble fraction from Calotropis gigantea (L.) W.T.Aiton flowers showed moderate DPPH free radical scavenging activity with an IC 50 value of 55.8  μ g/mL. Thus, a further phytochemical study was carried out to obtain five alkaloids, including a new β -carboline-type alkaloid, caloside H ( 1 ). These known compounds were identified as 5-hydroxy-(2-methoxymethyl)pyridine ( 2 ), nicotinic acid ( 3 ), p -(acetylamino)phenol ( 4 ), and thymine ( 5 ). These structures were determined based on the NMR spectroscopic analysis. In antioxidant assay, caloside H at concentration of 100  μ M showed DPPH radical scavenging capacity with a percentage of inhibition of 40.2%. In addition, a plausible biosynthetic pathway for the formation of caloside H was proposed based on the Schiff base formation and Mannich-like reaction.

Multisystemic inflammatory syndrome in children (MIS-C) might manifest in a broad spectrum of clinical scenarios, ranging from mild features to multi-organ dysfunction and mortality. However, this novel entity has a heterogenicity of data regarding prognostic factors associated with severe outcomes. The present study aimed to identify independent predictors for severity by using multivariate regression models. A total of 391 patients (255 boys and 136 girls) were admitted to Vietnam National Children's Hospital from January 2022 to June 2023. The median age was 85 (range: 2-188) months, and only 12 (3.1%) patients had comorbidities. 161 (41.2%) patients required PICU admission, and the median PICU LOS was 4 (2-7) days. We observed independent factors related to PICU admission, including CRP ≥ 50 (mg/L) (OR 2.52, 95% CI 1.39-4.56, p = 0.002), albumin ≤ 30 (g/L) (OR 3.18, 95% CI 1.63-6.02, p = 0.001), absolute lymphocyte count ≤ 2 (× 10 9 /L) (OR 2.18, 95% CI 1.29-3.71, p = 0.004), ferritin ≥ 300 (ng/mL) (OR 2.35, 95% CI 1.38-4.01), p = 0.002), and LVEF < 60 (%) (OR 2.48, 95% CI 1.28-4.78, p = 0.007). Shock developed in 140 (35.8%) patients, especially for those decreased absolute lymphocyte ≤ 2 (× 10 9 /L) (OR 2.48, 95% CI 1.10-5.61, p = 0.029), albumin ≤ 30 (g/L) (OR 2.53, 95% CI 1.22-5.24, p = 0.013), or LVEF < 60 (%) (OR 2.24, 95% CI 1.12-4.51, p = 0.022). In conclusion, our study emphasized that absolute lymphocyte count, serum albumin, CRP, and LVEF were independent predictors for MIS-C severity. Further well-designed investigations are required to validate their efficacy in predicting MIS-C severe cases, especially compared to other parameters. As MIS-C is a new entity and severe courses may progress aggressively, identifying high-risk patients optimizes clinicians' follow-up and management to improve disease outcomes., (© 2024. The Author(s).)

Background: The highest burden of disease from hepatitis C virus (HCV) is found in Southeast Asia, but our understanding of the epidemiology of infection in many heavily burdened countries is still limited. In particular, there is relatively little data on acute HCV infection, the outcome of which can be influenced by both viral and host genetics which differ within the region. We studied HCV genotype and IL28B gene polymorphism in a cohort of acute HCV-infected patients in Southern Vietnam alongside two other cohorts of chronic HCV-infected patients to better understand the epidemiology of HCV infection locally and inform the development of programs for therapy with the increasing availability of directly acting antiviral therapy (DAAs)., Methods: We analysed plasma samples from patients with acute and chronic HCV infection, including chronic HCV mono-infection and chronic Human Immunodeficiency Virus (HIV)-HCV coinfection, who enrolled in four epidemiological or clinical research studies. HCV infection was confirmed with RNA testing. The 5' UTR, core and NSB5 regions of HCV RNA positive samples were sequenced, and the genotype and subtype of the viral strains were determined. Host DNA from all HCV positive patients and age- and sex-matched non-HCV-infected control individuals were analysed for IL28B single nucleotide polymorphism (SNP) (rs12979860 and rs8099917). Geolocation of the patients were mapped using QGIS., Results: 355 HCV antibody positive patients were analysed; 54.6% (194/355) and 46.4% (161/355) were acute and chronic infections, respectively. 50.4% (81/161) and 49.6.4% (80/161) of chronic infections had HCV mono-infection and HIV-HCV coinfection, respectively. 88.7% (315/355) and 10.1% (36/355) of the patients were from southern and central regions of Vietnam, respectively. 92.4% (328/355) of patients were HCV RNA positive, including 86.1% (167/194) acute and 100% (161/161) chronic infections. Genotype could be determined in 98.4% (322/328) patients. Genotypes 1 (56.5%; 182/322) and 6 (33.9%; 109/322) predominated. Genotype 1 including genotype 1a was significantly higher in HIV-HCV coinfected patients compared to acute HCV patients [43.8% (35/80) versus 20.5% (33/167)], (p = <0.001), while genotype 6 was significantly higher in chronic HCV mono-infected patients [(44.4% (36/81) versus 20.0% (16/80)] (p = < 0.004) compared to HIV-HCV coinfected patients. The prevalence of IL28B SNP (rs12979860) homozygous CC was 86.46% (83/96) in control individuals and was significantly higher in acutely-infected compared to chronically-infected patients [93.2 (82/88) versus 76.1% (35/46)] (p = < 0.005)., Conclusion: HCV genotype 6 is highly prevalent in Vietnam and the high prevalence in treatment naïve chronic HCV patients may results from poor spontaneous clearance of acute HCV infection with genotype 6., Competing Interests: This study was partly funded by Roche molecular diagnostics, the employer of Gabrielle M. Heilek. Two authors, Karen Saylors and Nathan Wolfe (part of the group authorship) are affiliated to Metabiota. There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Background: The burden of obesity in Vietnam has not been well defined because there is a lack of reference data for percent body fat (PBF) in Asians. This study sought to define the relationship between PBF and body mass index (BMI) in the Vietnamese population., Methods: The study was designed as a comparative cross-sectional investigation that involved 1217 individuals of Vietnamese background (862 women) aged 20 years and older (average age 47 yr) who were randomly selected from the general population in Ho Chi Minh City. Lean mass (LM) and fat mass (FM) were measured by DXA (Hologic QDR 4500). PBF was derived as FM over body weight., Results: Based on BMI ≥30, the prevalence of obesity was 1.1% and 1.3% for men and women, respectively. The prevalence of overweight and obesity combined (BMI ≥25) was ~24% and ~19% in men and women, respectively. Based on the quadratic relationship between BMI and PBF, the approximate PBF corresponding to the BMI threshold of 30 (obese) was 30.5 in men and 41 in women. Using the criteria of PBF >30 in men and PBF >40 in women, approximately 15% of men and women were considered obese., Conclusion: These data suggest that body mass index underestimates the prevalence of obesity. We suggest that a PBF >30 in men or PBF >40 in women is used as criteria for the diagnosis of obesity in Vietnamese adults. Using these criteria, 15% of Vietnamese adults in Ho Chi Minh City was considered obese.

Objectives: Male sex workers (MSW) in Vietnam face high levels of stigma related to sex work, which may be associated with depression and increased vulnerability to HIV., Methods: In 2010, 300 MSW completed a behavioral and psychosocial survey. Multivariable models assessed factors associated with sex work-related stigma and the association between stigma and depression., Results: Factors associated with increased stigma included having disclosed sexual orientation to healthcare workers (b 1.75, 95 % CI 0.69-2.80), meeting clients in the street/park (b 1.42, 95 % CI 0.32-2.52), and having been forced to have sex without a condom (b 2.36, 95 % CI 1.27-3.45). Factors associated with decreased stigma included meeting clients via the telephone or internet (b -1.26, 95 % CI -2.39 to -0.12) and receiving financial support from family or friends (b -1.31, 95 % CI -2.46 to -0.17). Stigma was significantly associated with increased odds of depression (AOR 1.07, 95 % CI 1.01-1.15)., Conclusions: Addressing stigma and depression in HIV prevention interventions is crucial for tailoring these programs to MSWs' needs, and may result in decreased HIV spread.

Background: Sporadic emergence of the highly pathogenic avian influenza (HPAI) H5N1 virus infection in humans is a serious concern because of the potential for a pandemic. Conventional or quantitative RT-PCR is the standard laboratory test to detect viral influenza infections. However, this technology requires well-equipped laboratories and highly trained personnel. A rapid, sensitive, and specific alternative screening method is needed., Methods: By a luminescence-linked enzyme immunoassay, we have developed a H5N1 HPAI virus detection kit using anti-H5 hemagglutinin monoclonal antibodies in combination with the detection of a universal NP antigen of the type A influenza virus. The process takes 15 minutes by use of the fully automated luminescence analyzer, POCube., Resutls: We tested this H5/A kit using 19 clinical specimens from 13 patients stored in Vietnam who were infected with clade 1.1 or clade 2.3.4 H5N1 HPAI virus. Approximately 80% of clinical specimens were H5-positive using the POCube system, whereas only 10% of the H5-positive samples were detected as influenza A-positive by an immunochromatography-based rapid diagnostic kit., Conclusions: This novel H5/A kit using POCube is served as a rapid and sensitive screening test for H5N1 HPAI virus infection in humans.

Influenza virus infections result in considerable morbidity and mortality both in the temperate and tropical world. Influenza surveillance over multiple years is important to determine the impact and epidemiology of influenza and to develop a national vaccine policy, especially in countries developing influenza vaccine manufacturing capacity, such as Vietnam. We conducted surveillance of influenza and influenza-like illness in Vietnam through the National Influenza Surveillance System during 2006-2010. At 15 sentinel sites, the first two patients presenting each weekday with influenza-like illness (ILI), defined as fever and cough and/or sore throat with illness onset within 3 days, were enrolled and throat specimens were collected and tested for influenza virus type and influenza A subtype by RT-PCR. De-identified demographic and provider reported subsequent hospitalization information was collected on each patient. Each site also collected information on the total number of patients with influenza-like illness evaluated per week. Of 29,804 enrolled patients presenting with influenza-like illness, 6516 (22%) were influenza positive. Of enrolled patients, 2737 (9.3%) were reported as subsequently hospitalized; of the 2737, 527 (19%) were influenza positive. Across all age groups with ILI, school-aged children had the highest percent of influenza infection (29%) and the highest percent of subsequent hospitalizations associated with influenza infection (28%). Influenza viruses co-circulated throughout most years in Vietnam during 2006-2010 and often reached peak levels multiple times during a year, when >20% of tests were influenza positive. Influenza is an important cause of all influenza-like illness and provider reported subsequent hospitalization among outpatients in Vietnam, especially among school-aged children. These findings may have important implications for influenza vaccine policy in Vietnam., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Major depression is increasing world-wide, and is the fourth leading cause of the global disease burden. Depression is rarely diagnosed in primary care settings in Vietnam, and those afflicted usually only seek professional care when the illness has become very severe. Depressive disorders affecting mothers are an important cause of low birth-weight, childhood stunting, under nutrition and adverse mental development, and a study has shown a 33% prevalence of postnatal depression symptoms in Ho Chi Minh City., Methods: The aim of this study was to elicit Illness Explanatory Models (EMs) of depression and postnatal depression from nine mothers and nine health workers. The study was conducted in a semi-rural area in Vietnam, and the EMs were elicited through semi-structured interviews where a case vignette of depression was used as the basis of questioning., Results: The EMs elicited were predominantly somatosocial in nature and the mothers assigned a strong personal responsibility for care. Psychiatric treatment and care was seldom recommended. Lack of communication was described as an important factor concealing depression, and together with the lack of care-seeking can be expected to impede effective treatment., Limitations: The results of this study cannot be generalised beyond the group studied, or the context of Ba Vi, though we believe that analytical generalisation to other contexts can be made. CONCLUSION (CLINICAL RELEVANCE): The results of this study highlight the importance of depression and postnatal depression being diagnosed in primary care, and of a cross-sectoral approach for the prevention of depression in Vietnam, which takes into account the social causation of depression in women.

Although universal access to quality health services is a primary policy goal of the Government of Vietnam (GOVN), economic restructuring and privatization of health services have been associated with emerging inequities in access to care. A GOVN programme for socio-economic development known as Program 135 (P135) designates communes known to be relatively poor as priority localities for development resources. Under this programme, basic curative and preventive health services, including some prescription drugs, are provided free of charge at commune health centres (CHCs). In an effort to improve the quality of care provided at CHCs, the national Ministry of Health (MOH) has implemented a set of national benchmarks for commune health care, which defines a minimum configuration of equipment, staff, training and other elements of service provision. This research examines the impact of P135 poverty reduction policy, achievement of MOH benchmark indicators and commune socio-economic characteristics on CHC utilization rates in Thai Nguyen Province, Vietnam. The analysis uses administrative data reported from 178 CHCs in Thai Nguyen Province for nine quarters, including 2004, 2005 and the first quarter of 2006. Mixed linear regression models are used to estimate the main and interaction effects on utilization rates of exposure to the P135 policies, achievement of MOH benchmarks, poverty, distance to the district hospital and ethnic composition. Communes that are poor and remote have comparatively high CHC utilization rates. Multivariate regression results suggest that communes exposed to the P135 policy have higher utilization rates, but these effects are conditional upon achievement of benchmark standards, thus perceived quality care enhances CHC utilization. Combining Program P135 with benchmark investment reduced the gap between primary health care utilization in poor communes versus those that are less poor. These commune-level findings suggest that CHC policies differentially benefit poor communities and reduce inequality in use of health care services.

There is a high incidence of pediatric asthma in Vietnam, but little lung function data are available. The aim of the study was to compare respiratory resistance (Rrs), reactance (Xrs), and responses to salbutamol between asthmatic and healthy primary school children in Hanoi. Because respiratory mechanics vary along the breathing cycle, measurements were assessed separately in inspiration (Rrsi, Xrsi) and expiration (Rrse, Xrse).Inpatients with doctor-diagnosed asthma were measured 2-3 days following admission using the forced oscillation technique (FOT) at a single frequency (8 Hz). Z-scores and responses to salbutamol were compared between 102 asthmatics and 98 controls, and accuracy of group classification by FOT parameters was assessed by Youden index, an indicator to the proportion of subjects correctly classified in each group.In asthmatics versus controls, Rrsi-but not Rrse-was significantly larger and both Xrsi and Xrse were significantly more negative (P < 0.01). Both Rrs and Xrs responses to salbutamol were significantly larger in asthmatics than controls (P < 0.001). Youden indexes indicated response to salbutamol generally had better diagnostic values than Z-scores and was best discriminative first with Rrsi, then with Xrse.It is concluded that different FOT characteristics may be described in asthmatic and healthy Vietnamese children. The diagnostic value of each parameter depends upon the breathing cycle. Most useful in practice probably is the response to salbutamol measured by Rrsi.

In 2006, national influenza surveillance was implemented in Vietnam. Epidemiologic and demographic data and a throat swab for influenza testing were collected from a subset of outpatients with influenza-like illness (ILI). During January 1, 2006 through December 31, 2007, of 184,521 ILI cases identified at surveillance sites, 11,082 were tested and 2112 (19%) were positive for influenza by reverse transcription polymerase chain reaction. Influenza viruses were detected year-round, and similar peaks in influenza activity were observed in all surveillance regions, coinciding with cooler and rainy periods. Studies are needed to ascertain the disease burden and impact of influenza in Vietnam.

A high incidence of childhood asthma has been reported in Ha Noi, Viet Nam, indicating a need to document lung function in these children. The degree of airway obstruction and reversibility may be evaluated from the forced oscillation assessment of respiratory resistance to reactance (Rrs, Xrs). Appropriate controls are necessary for a proper interpretation of patients. The aim of the study was to provide reference values on Rrs and Xrs and response to salbutamol in healthy Vietnamese children. One hundred seventy-five children aged 6-11 year recruited from one public school in Ha Noi were studied. Measurements were obtained at baseline and after 200 microg inhaled salbutamol. Significant correlations were disclosed between Rrs or Xrs and standing height (P < 0.0001). Salbutamol significantly decreased Rrs (from 7.1 +/- 1.9 hPa.sec/L to 6.2 +/- 1.8 hPa sec/L, P < 0.0001) and increased Xrs (from -1.22 +/- 0.64 to -0.91 +/- 0.61 hPa.sec/L, P < 0.0001). Rrs response to salbutamol lower limit of 95% confidence interval was -38% from baseline Rrs and, Xrs upper limit was +16% from baseline impedance. It is concluded that reference values for respiratory impedance (Zrs) and thresholds for clinically relevant response to bronchodilator are provided in primary school Vietnamese children. A smaller slope for the observed Rrs-body height relationship is suggested with reference to relevant studies in healthy Caucasians., ((c) 2008 Wiley-Liss, Inc.)

Influenza A virus has the ability to overcome immunity from previous infections through the acquisition of genetic changes. Thus, understanding the evolution of the viruses in humans is important for the surveillance and the selection of vaccine strains. A total of 30 influenza A/H3N2 viruses and 35 influenza A/H1N1 viruses that were collected in Vietnam from 2001 to 2006 were used to analyze the evolution of the hemagglutinin (HA), neuraminidase (NA), and matrix protein (M) genes. Phylogenetic analysis of individual gene segments revealed that the HA and the NA genes of the influenza A viruses evolved in a sequential way. However, the evolutionary pattern of the M gene proved to be nonlinear and was not linked with that of the HA and NA genes. Genetic drift in HA1 segments, especially in the antigenic sites of A/H3N2 viruses, occurred more frequently in A/H3N2 viruses than it did in A/H1N1 viruses. Two reassortants, one influenza A/H3N2 strain and one A/H1N1 strain, were found on the basis of the phylogenetic analysis of the three genes. While both genetic mutation and reassortment contributed to their evolution, the frequency of genetic changes and reassortment events differs between the two subtypes. As influenza viruses circulate throughout the year, we emphasize the importance of surveillance in tropical and subtropical zones, where the emergence of new strains may be detected earlier than it is in temperate zones.

Background: The reproducibilty of dengue IgM and IgG ELISA was studied in serum and filter paper blood spots from Vietnamese febrile patients., Methods: 781 pairs of acute (t0) and convalescent sera, obtained after three weeks (t3) and 161 corresponding pairs of filter paper blood spots were tested with ELISA for dengue IgG and IgM. 74 serum pairs were tested again in another laboratory with similar methods, after a mean of 252 days., Results: Cases were classified as no dengue (10 %), past dengue (55%) acute primary (7%) or secondary (28%) dengue. Significant differences between the two laboratories' results were found leading to different diagnostic classification (kappa 0.46, p < 0.001). Filter paper results correlated poorly to serum values, being more variable and lower with a mean (95% CI) difference of 0.82 (0.36 to 1.28) for IgMt3, 0.94 (0.51 to 1.37) for IgGt0 and 0.26 (-0.20 to 0.71) for IgGt3. This also led to differences in diagnostic classification (kappa value 0.44, p < 0.001) The duration of storage of frozen serum and dried filter papers, sealed in nylon bags in an air-conditioned room, had no significant effect on the ELISA results., Conclusion: Dengue virus IgG antibodies in serum and filter papers was not affected by duration of storage, but was subject to inter-laboratory variability. Dengue virus IgM antibodies measured in serum reconstituted from blood spots on filter papers were lower than in serum, in particular in the acute phase of disease. Therefore this method limits its value for diagnostic confirmation of individual patients with dengue virus infections. However the detection of dengue virus IgG antibodies eluted from filter paper can be used for sero-prevalence cross sectional studies.

Fallout 239+240Pu, 238Pu, 90Sr and 137Cs inventories in surface soils were measured for 20 locations in northern Vietnam yielding the mean values (+/- standard error) of 26.5+/-3.8 Bq m(-2) for 239+240Pu, 1048+/-143 Bq m(-2) for 137Cs and 212+/-28 Bq m(-2) for 90Sr. The concentrations of 137Cs and plutonium isotopes strongly correlate with each other resulting in a stable 239+240Pu/137Cs inventory ratio of 0.025+/-0.002. Among soil parameters, organic matter and fulvic acids strongly correlate with caesium and plutonium isotopes, especially in the 0-10 cm layer. 137Cs and 239+240Pu are distributed rather similarly over the 0-10 cm and 10-20 cm layers. At locations with high contents of sand (82-93%) along the South China Sea coast, the downward percolation by rainwater results in a higher accumulation of 239+240Pu and 137Cs in the 10-20 cm layer. The mean 137Cs/ 90Sr inventory ratio is 9.3+/-2.2, and the correlation is weak between these isotopes.

Aims: To obtain comprehensive pharmacokinetic and pharmacodynamic data for artesunate (ARTS) and its active metabolite dihydroartemisinin (DHA) following i.v. and oral administration of ARTS to patients with acute, uncomplicated falciparum malaria., Methods: Twenty-six Vietnamese patients with falciparum malaria were randomized to receive either i.v. ARTS (120 mg; group 1) or oral ARTS (100 mg; group 2), with the alternative preparation given 8 h later in an open crossover design. Mefloquine (750 mg) was administered at 24 h. Plasma concentrations of ARTS and DHA were determined by h.p.l.c. assay. Pharmacokinetic parameters were calculated by non-compartmental methods. The time to 50% parasite clearance (PCT50) was calculated by linear interpolation of parasite density determinations. Linear least squares and multiple linear regression analyses were used to evaluate pharmacokinetic-pharmacodynamic relationships., Results: Following i.v. bolus, ARTS had a peak concentration of 29.5 microM (11 mg l[-1]), elimination t1/2 = 2.7 min, CL = 2.33 l h(-1) kg(-1) and V = 0.14 l kg(-1). The Cmax for DHA was 9.3 microM (2.64 mg l[-1]), t1/2 = 40 min, CL =0.75 l h(-1) kg(-1) and V = 0.76 l kg(-1). Following oral ARTS, relative bioavailability of DHA was 82%, Cmax was 2.6 microM (0.74 mg l[-1]), t1/2 = 39 min, and MAT = 67 min. Overall, the PCT50 and fever clearance time (FCT) were 6.5 h and 24 h, respectively. There was no correlation between PCT50 or FCT and AUC, Cmax or MRT for DHA., Conclusions: Despite rapid clearance of ARTS and DHA in patients with uncomplicated falciparum malaria, prompt parasite and fever clearance were achieved. High relative bioavailability of DHA following oral ARTS administration, and clinical outcomes comparable with those after i.v. ARTS, support the use of the oral formulation in the primary care setting.

Situated in Southeast Asia, with a tropical monsoon climate, Vietnam is covered by tropical rain forests over one-quarter of its surface. Forests have been extremely important in the country's economy and they will be essential in its future development. Forests contribute directly to the economy through the provision of building materials and energy and indirectly through foreign exchange earnings, which amount to about US$200 million annually. Forests play a key role in the conservation of biodiversity. They protect watersheds and thus contribute to flood control and water management in the highly productive delta regions. In order for the forests to contribute to the national economy, strong forest management institutions and proper policies are necessary. Forest land use and exploitation should be strictly controlled, and effective programs must be developed. The potential of the forests can only be realized on a sustainable basis through significant changes in current practices.